diff options
Diffstat (limited to 'absl/flags/internal')
| -rw-r--r-- | absl/flags/internal/commandlineflag.cc | 383 | ||||
| -rw-r--r-- | absl/flags/internal/commandlineflag.h | 365 | ||||
| -rw-r--r-- | absl/flags/internal/commandlineflag_test.cc | 196 | ||||
| -rw-r--r-- | absl/flags/internal/flag.h | 103 | ||||
| -rw-r--r-- | absl/flags/internal/parse.h | 48 | ||||
| -rw-r--r-- | absl/flags/internal/path_util.h | 60 | ||||
| -rw-r--r-- | absl/flags/internal/path_util_test.cc | 46 | ||||
| -rw-r--r-- | absl/flags/internal/program_name.cc | 53 | ||||
| -rw-r--r-- | absl/flags/internal/program_name.h | 47 | ||||
| -rw-r--r-- | absl/flags/internal/program_name_test.cc | 60 | ||||
| -rw-r--r-- | absl/flags/internal/registry.cc | 529 | ||||
| -rw-r--r-- | absl/flags/internal/registry.h | 168 | ||||
| -rw-r--r-- | absl/flags/internal/type_erased.cc | 121 | ||||
| -rw-r--r-- | absl/flags/internal/type_erased.h | 97 | ||||
| -rw-r--r-- | absl/flags/internal/type_erased_test.cc | 147 | ||||
| -rw-r--r-- | absl/flags/internal/usage.cc | 392 | ||||
| -rw-r--r-- | absl/flags/internal/usage.h | 91 | ||||
| -rw-r--r-- | absl/flags/internal/usage_test.cc | 367 |
18 files changed, 3273 insertions, 0 deletions
diff --git a/absl/flags/internal/commandlineflag.cc b/absl/flags/internal/commandlineflag.cc new file mode 100644 index 000000000000..744447219c71 --- /dev/null +++ b/absl/flags/internal/commandlineflag.cc @@ -0,0 +1,383 @@ +// +// Copyright 2019 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#include "absl/flags/internal/commandlineflag.h" + +#include <cassert> + +#include "absl/base/internal/raw_logging.h" +#include "absl/base/optimization.h" +#include "absl/flags/config.h" +#include "absl/flags/usage_config.h" +#include "absl/strings/str_cat.h" +#include "absl/synchronization/mutex.h" + +namespace absl { +namespace flags_internal { + +// The help message indicating that the commandline flag has been +// 'stripped'. It will not show up when doing "-help" and its +// variants. The flag is stripped if ABSL_FLAGS_STRIP_HELP is set to 1 +// before including absl/flags/flag.h + +// This is used by this file, and also in commandlineflags_reporting.cc +const char kStrippedFlagHelp[] = "\001\002\003\004 (unknown) \004\003\002\001"; + +namespace { + +void StoreAtomic(CommandLineFlag* flag, const void* data, size_t size) { + int64_t t = 0; + assert(size <= sizeof(int64_t)); + memcpy(&t, data, size); + flag->atomic.store(t, std::memory_order_release); +} + +// If the flag has a mutation callback this function invokes it. While the +// callback is being invoked the primary flag's mutex is unlocked and it is +// re-locked back after call to callback is completed. Callback invocation is +// guarded by flag's secondary mutex instead which prevents concurrent callback +// invocation. Note that it is possible for other thread to grab the primary +// lock and update flag's value at any time during the callback invocation. +// This is by design. Callback can get a value of the flag if necessary, but it +// might be different from the value initiated the callback and it also can be +// different by the time the callback invocation is completed. +// Requires that *primary_lock be held in exclusive mode; it may be released +// and reacquired by the implementation. +void InvokeCallback(CommandLineFlag* flag, absl::Mutex* primary_lock) + EXCLUSIVE_LOCKS_REQUIRED(primary_lock) { + if (!flag->callback) return; + + // The callback lock is guaranteed initialized, because *primary_lock exists. + absl::Mutex* callback_mu = &flag->locks->callback_mu; + + // When executing the callback we need the primary flag's mutex to be unlocked + // so that callback can retrieve the flag's value. + primary_lock->Unlock(); + + { + absl::MutexLock lock(callback_mu); + + flag->callback(); + } + + primary_lock->Lock(); +} + +// Currently we only validate flag values for user-defined flag types. +bool ShouldValidateFlagValue(const CommandLineFlag& flag) { +#define DONT_VALIDATE(T) \ + if (flag.IsOfType<T>()) return false; + ABSL_FLAGS_INTERNAL_FOR_EACH_LOCK_FREE(DONT_VALIDATE) + DONT_VALIDATE(std::string) + DONT_VALIDATE(std::vector<std::string>) +#undef DONT_VALIDATE + + return true; +} + +} // namespace + +// Update any copy of the flag value that is stored in an atomic word. +// In addition if flag has a mutation callback this function invokes it. +void UpdateCopy(CommandLineFlag* flag, absl::Mutex* primary_lock) + EXCLUSIVE_LOCKS_REQUIRED(primary_lock) { +#define STORE_ATOMIC(T) \ + else if (flag->IsOfType<T>()) { \ + StoreAtomic(flag, flag->cur, sizeof(T)); \ + } + + if (false) { + } + ABSL_FLAGS_INTERNAL_FOR_EACH_LOCK_FREE(STORE_ATOMIC) +#undef STORE_ATOMIC + + InvokeCallback(flag, primary_lock); +} + +// Ensure that the lazily initialized fields of *flag have been initialized, +// and return &flag->locks->primary_mu. +absl::Mutex* InitFlagIfNecessary(CommandLineFlag* flag) + LOCK_RETURNED(flag->locks->primary_mu) { + absl::Mutex* mu; + if (!flag->inited.load(std::memory_order_acquire)) { + // Need to initialize lazily initialized fields. + ABSL_CONST_INIT static absl::Mutex init_lock(absl::kConstInit); + init_lock.Lock(); + if (flag->locks == nullptr) { // Must initialize Mutexes for this flag. + flag->locks = new flags_internal::CommandLineFlagLocks; + } + mu = &flag->locks->primary_mu; + init_lock.Unlock(); + mu->Lock(); + if (!flag->retired && + flag->def == nullptr) { // Need to initialize def and cur fields. + flag->def = (*flag->make_init_value)(); + flag->cur = Clone(flag->op, flag->def); + UpdateCopy(flag, mu); + } + mu->Unlock(); + flag->inited.store(true, std::memory_order_release); + } else { // All fields initialized; flag->locks is therefore safe to read. + mu = &flag->locks->primary_mu; + } + return mu; +} + +// Return true iff flag value was changed via direct-access. +bool ChangedDirectly(CommandLineFlag* flag, const void* a, const void* b) { + if (!flag->IsAbseilFlag()) { + // Need to compare values for direct-access flags. +#define CHANGED_FOR_TYPE(T) \ + if (flag->IsOfType<T>()) { \ + return *reinterpret_cast<const T*>(a) != *reinterpret_cast<const T*>(b); \ + } + + CHANGED_FOR_TYPE(bool); + CHANGED_FOR_TYPE(int32_t); + CHANGED_FOR_TYPE(int64_t); + CHANGED_FOR_TYPE(uint64_t); + CHANGED_FOR_TYPE(double); + CHANGED_FOR_TYPE(std::string); +#undef CHANGED_FOR_TYPE + } + return false; +} + +// Direct-access flags can be modified without going through the +// flag API. Detect such changes and updated the modified bit. +void UpdateModifiedBit(CommandLineFlag* flag) { + if (!flag->IsAbseilFlag()) { + absl::MutexLock l(InitFlagIfNecessary(flag)); + if (!flag->modified && ChangedDirectly(flag, flag->cur, flag->def)) { + flag->modified = true; + } + } +} + +bool Validate(CommandLineFlag*, const void*) { + return true; +} + +std::string HelpText::GetHelpText() const { + if (help_function_) return help_function_(); + if (help_message_) return help_message_; + + return {}; +} + +const int64_t CommandLineFlag::kAtomicInit; + +void CommandLineFlag::Read(void* dst, + const flags_internal::FlagOpFn dst_op) const { + absl::ReaderMutexLock l( + InitFlagIfNecessary(const_cast<CommandLineFlag*>(this))); + + // `dst_op` is the unmarshaling operation corresponding to the declaration + // visibile at the call site. `op` is the Flag's defined unmarshalling + // operation. They must match for this operation to be well-defined. + if (ABSL_PREDICT_FALSE(dst_op != op)) { + ABSL_INTERNAL_LOG( + ERROR, + absl::StrCat("Flag '", name, + "' is defined as one type and declared as another")); + } + CopyConstruct(op, cur, dst); +} + +void CommandLineFlag::Write(const void* src, + const flags_internal::FlagOpFn src_op) { + absl::Mutex* mu = InitFlagIfNecessary(this); + absl::MutexLock l(mu); + + // `src_op` is the marshalling operation corresponding to the declaration + // visible at the call site. `op` is the Flag's defined marshalling operation. + // They must match for this operation to be well-defined. + if (ABSL_PREDICT_FALSE(src_op != op)) { + ABSL_INTERNAL_LOG( + ERROR, + absl::StrCat("Flag '", name, + "' is defined as one type and declared as another")); + } + + if (ShouldValidateFlagValue(*this)) { + void* obj = Clone(op, src); + std::string ignored_error; + std::string src_as_str = Unparse(marshalling_op, src); + if (!Parse(marshalling_op, src_as_str, obj, &ignored_error) || + !Validate(this, obj)) { + ABSL_INTERNAL_LOG(ERROR, absl::StrCat("Attempt to set flag '", name, + "' to invalid value ", src_as_str)); + } + Delete(op, obj); + } + + modified = true; + counter++; + Copy(op, src, cur); + + UpdateCopy(this, mu); +} + +absl::string_view CommandLineFlag::Typename() const { + // We do not store/report type in Abseil Flags, so that user do not rely on in + // at runtime + if (IsAbseilFlag() || IsRetired()) return ""; + +#define HANDLE_V1_BUILTIN_TYPE(t) \ + if (IsOfType<t>()) { \ + return #t; \ + } + + HANDLE_V1_BUILTIN_TYPE(bool); + HANDLE_V1_BUILTIN_TYPE(int32_t); + HANDLE_V1_BUILTIN_TYPE(int64_t); + HANDLE_V1_BUILTIN_TYPE(uint64_t); + HANDLE_V1_BUILTIN_TYPE(double); +#undef HANDLE_V1_BUILTIN_TYPE + + if (IsOfType<std::string>()) { + return "string"; + } + + return ""; +} + +std::string CommandLineFlag::Filename() const { + return flags_internal::GetUsageConfig().normalize_filename(this->filename); +} + +std::string CommandLineFlag::DefaultValue() const { + return Unparse(this->marshalling_op, this->def); +} + +std::string CommandLineFlag::CurrentValue() const { + return Unparse(this->marshalling_op, this->cur); +} + +void CommandLineFlag::SetCallback( + const flags_internal::FlagCallback mutation_callback) { + absl::Mutex* mu = InitFlagIfNecessary(this); + absl::MutexLock l(mu); + + callback = mutation_callback; + + InvokeCallback(this, mu); +} + +// Attempts to parse supplied `value` string using parsing routine in the `flag` +// argument. If parsing is successful, it will try to validate that the parsed +// value is valid for the specified 'flag'. Finally this function stores the +// parsed value in 'dst' assuming it is a pointer to the flag's value type. In +// case if any error is encountered in either step, the error message is stored +// in 'err' +static bool TryParseLocked(CommandLineFlag* flag, void* dst, + absl::string_view value, std::string* err) { + void* tentative_value = Clone(flag->op, flag->def); + std::string parse_err; + if (!Parse(flag->marshalling_op, value, tentative_value, &parse_err)) { + auto type_name = flag->Typename(); + absl::string_view err_sep = parse_err.empty() ? "" : "; "; + absl::string_view typename_sep = type_name.empty() ? "" : " "; + *err = absl::StrCat("Illegal value '", value, "' specified for", + typename_sep, type_name, " flag '", flag->Name(), "'", + err_sep, parse_err); + Delete(flag->op, tentative_value); + return false; + } + + if (!Validate(flag, tentative_value)) { + *err = absl::StrCat("Failed validation of new value '", + Unparse(flag->marshalling_op, tentative_value), + "' for flag '", flag->Name(), "'"); + Delete(flag->op, tentative_value); + return false; + } + + flag->counter++; + Copy(flag->op, tentative_value, dst); + Delete(flag->op, tentative_value); + return true; +} + +// Sets the value of the flag based on specified string `value`. If the flag +// was successfully set to new value, it returns true. Otherwise, sets `err` +// to indicate the error, leaves the flag unchanged, and returns false. There +// are three ways to set the flag's value: +// * Update the current flag value +// * Update the flag's default value +// * Update the current flag value if it was never set before +// The mode is selected based on 'set_mode' parameter. +bool CommandLineFlag::SetFromString(absl::string_view value, + FlagSettingMode set_mode, + ValueSource source, std::string* err) { + if (IsRetired()) return false; + + UpdateModifiedBit(this); + + absl::Mutex* mu = InitFlagIfNecessary(this); + absl::MutexLock l(mu); + + switch (set_mode) { + case SET_FLAGS_VALUE: { + // set or modify the flag's value + if (!TryParseLocked(this, this->cur, value, err)) return false; + this->modified = true; + UpdateCopy(this, mu); + + if (source == kCommandLine) { + this->on_command_line = true; + } + break; + } + case SET_FLAG_IF_DEFAULT: { + // set the flag's value, but only if it hasn't been set by someone else + if (!this->modified) { + if (!TryParseLocked(this, this->cur, value, err)) return false; + this->modified = true; + UpdateCopy(this, mu); + } else { + // TODO(rogeeff): review and fix this semantic. Currently we do not fail + // in this case if flag is modified. This is misleading since the flag's + // value is not updated even though we return true. + // *err = absl::StrCat(this->Name(), " is already set to ", + // CurrentValue(), "\n"); + // return false; + return true; + } + break; + } + case SET_FLAGS_DEFAULT: { + // modify the flag's default-value + if (!TryParseLocked(this, this->def, value, err)) return false; + + if (!this->modified) { + // Need to set both defvalue *and* current, in this case + Copy(this->op, this->def, this->cur); + UpdateCopy(this, mu); + } + break; + } + default: { + // unknown set_mode + assert(false); + return false; + } + } + + return true; +} + +} // namespace flags_internal +} // namespace absl diff --git a/absl/flags/internal/commandlineflag.h b/absl/flags/internal/commandlineflag.h new file mode 100644 index 000000000000..4815cdc7c9a2 --- /dev/null +++ b/absl/flags/internal/commandlineflag.h @@ -0,0 +1,365 @@ +// +// Copyright 2019 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#ifndef ABSL_FLAGS_INTERNAL_COMMANDLINEFLAG_H_ +#define ABSL_FLAGS_INTERNAL_COMMANDLINEFLAG_H_ + +#include <atomic> + +#include "absl/base/macros.h" +#include "absl/flags/marshalling.h" +#include "absl/synchronization/mutex.h" +#include "absl/types/optional.h" + +namespace absl { +namespace flags_internal { + +// Type-specific operations, eg., parsing, copying, etc. are provided +// by function specific to that type with a signature matching FlagOpFn. +enum FlagOp { + kDelete, + kClone, + kCopy, + kCopyConstruct, + kSizeof, + kParse, + kUnparse +}; +using FlagOpFn = void* (*)(FlagOp, const void*, void*); +using FlagMarshallingOpFn = void* (*)(FlagOp, const void*, void*, void*); + +// Options that control SetCommandLineOptionWithMode. +enum FlagSettingMode { + // update the flag's value unconditionally (can call this multiple times). + SET_FLAGS_VALUE, + // update the flag's value, but *only if* it has not yet been updated + // with SET_FLAGS_VALUE, SET_FLAG_IF_DEFAULT, or "FLAGS_xxx = nondef". + SET_FLAG_IF_DEFAULT, + // set the flag's default value to this. If the flag has not been updated + // yet (via SET_FLAGS_VALUE, SET_FLAG_IF_DEFAULT, or "FLAGS_xxx = nondef") + // change the flag's current value to the new default value as well. + SET_FLAGS_DEFAULT +}; + +// Options that control SetFromString: Source of a value. +enum ValueSource { + // Flag is being set by value specified on a command line. + kCommandLine, + // Flag is being set by value specified in the code. + kProgrammaticChange, +}; + +// Signature for the help generation function used as an argument for the +// absl::Flag constructor. +using HelpGenFunc = std::string (*)(); + +// Signature for the function generating the initial flag value based (usually +// based on default value supplied in flag's definition) +using InitialValGenFunc = void* (*)(); + +// Signature for the mutation callback used by watched Flags +// The callback is noexcept. +// TODO(rogeeff): add noexcept after C++17 support is added. +using FlagCallback = void (*)(); + +extern const char kStrippedFlagHelp[]; + +// The per-type function +template <typename T> +void* FlagOps(FlagOp op, const void* v1, void* v2) { + switch (op) { + case kDelete: + delete static_cast<const T*>(v1); + return nullptr; + case kClone: + return new T(*static_cast<const T*>(v1)); + case kCopy: + *static_cast<T*>(v2) = *static_cast<const T*>(v1); + return nullptr; + case kCopyConstruct: + new (v2) T(*static_cast<const T*>(v1)); + return nullptr; + case kSizeof: + return reinterpret_cast<void*>(sizeof(T)); + default: + return nullptr; + } +} + +template <typename T> +void* FlagMarshallingOps(FlagOp op, const void* v1, void* v2, void* v3) { + switch (op) { + case kParse: { + // initialize the temporary instance of type T based on current value in + // destination (which is going to be flag's default value). + T temp(*static_cast<T*>(v2)); + if (!absl::ParseFlag<T>(*static_cast<const absl::string_view*>(v1), &temp, + static_cast<std::string*>(v3))) { + return nullptr; + } + *static_cast<T*>(v2) = std::move(temp); + return v2; + } + case kUnparse: + *static_cast<std::string*>(v2) = + absl::UnparseFlag<T>(*static_cast<const T*>(v1)); + return nullptr; + default: + return nullptr; + } +} + +// Functions that invoke flag-type-specific operations. +inline void Delete(FlagOpFn op, const void* obj) { + op(flags_internal::kDelete, obj, nullptr); +} + +inline void* Clone(FlagOpFn op, const void* obj) { + return op(flags_internal::kClone, obj, nullptr); +} + +inline void Copy(FlagOpFn op, const void* src, void* dst) { + op(flags_internal::kCopy, src, dst); +} + +inline void CopyConstruct(FlagOpFn op, const void* src, void* dst) { + op(flags_internal::kCopyConstruct, src, dst); +} + +inline bool Parse(FlagMarshallingOpFn op, absl::string_view text, void* dst, + std::string* error) { + return op(flags_internal::kParse, &text, dst, error) != nullptr; +} + +inline std::string Unparse(FlagMarshallingOpFn op, const void* val) { + std::string result; + op(flags_internal::kUnparse, val, &result, nullptr); + return result; +} + +inline size_t Sizeof(FlagOpFn op) { + // This sequence of casts reverses the sequence from base::internal::FlagOps() + return static_cast<size_t>(reinterpret_cast<intptr_t>( + op(flags_internal::kSizeof, nullptr, nullptr))); +} + +// The following struct contains the locks in a CommandLineFlag struct. +// They are in a separate struct that is lazily allocated to avoid problems +// with static initialization and to avoid multiple allocations. +struct CommandLineFlagLocks { + absl::Mutex primary_mu; // protects several fields in CommandLineFlag + absl::Mutex callback_mu; // used to serialize callbacks +}; + +// Holds either a pointer to help text or a function which produces it. This is +// needed for supporting both static initialization of Flags while supporting +// the legacy registration framework. We can't use absl::variant<const char*, +// const char*(*)()> since anybody passing 0 or nullptr in to a CommandLineFlag +// would find an ambiguity. +class HelpText { + public: + static constexpr HelpText FromFunctionPointer(const HelpGenFunc fn) { + return HelpText(fn, nullptr); + } + static constexpr HelpText FromStaticCString(const char* msg) { + return HelpText(nullptr, msg); + } + + std::string GetHelpText() const; + + HelpText() = delete; + HelpText(const HelpText&) = default; + HelpText(HelpText&&) = default; + + private: + explicit constexpr HelpText(const HelpGenFunc fn, const char* msg) + : help_function_(fn), help_message_(msg) {} + + HelpGenFunc help_function_; + const char* help_message_; +}; + +// Holds all information for a flag. +struct CommandLineFlag { + constexpr CommandLineFlag( + const char* name_arg, HelpText help_text, const char* filename_arg, + const flags_internal::FlagOpFn op_arg, + const flags_internal::FlagMarshallingOpFn marshalling_op_arg, + const flags_internal::InitialValGenFunc initial_value_gen, + const bool retired_arg, void* def_arg, void* cur_arg) + : name(name_arg), + help(help_text), + filename(filename_arg), + op(op_arg), + marshalling_op(marshalling_op_arg), + make_init_value(initial_value_gen), + retired(retired_arg), + inited(false), + modified(false), + on_command_line(false), + validator(nullptr), + callback(nullptr), + def(def_arg), + cur(cur_arg), + counter(0), + atomic(kAtomicInit), + locks(nullptr) {} + + // Not copyable/assignable. + CommandLineFlag(const CommandLineFlag&) = delete; + CommandLineFlag& operator=(const CommandLineFlag&) = delete; + + absl::string_view Name() const { return name; } + std::string Help() const { return help.GetHelpText(); } + bool IsRetired() const { return this->retired; } + bool IsSpecifiedOnCommandLine() const { return on_command_line; } + // Returns true iff this is a handle to an Abseil Flag. + bool IsAbseilFlag() const { + // Set to null for V1 flags + return this->make_init_value != nullptr; + } + + absl::string_view Typename() const; + std::string Filename() const; + std::string DefaultValue() const; + std::string CurrentValue() const; + + // Return true iff flag has type T. + template <typename T> + inline bool IsOfType() const { + return this->op == &flags_internal::FlagOps<T>; + } + + // Attempts to retrieve the flag value. Returns value on success, + // absl::nullopt otherwise. + template <typename T> + absl::optional<T> Get() { + if (IsRetired() || flags_internal::FlagOps<T> != this->op) + return absl::nullopt; + + T res; + Read(&res, flags_internal::FlagOps<T>); + + return res; + } + + void SetCallback(const flags_internal::FlagCallback mutation_callback); + + // Sets the value of the flag based on specified std::string `value`. If the flag + // was successfully set to new value, it returns true. Otherwise, sets `error` + // to indicate the error, leaves the flag unchanged, and returns false. There + // are three ways to set the flag's value: + // * Update the current flag value + // * Update the flag's default value + // * Update the current flag value if it was never set before + // The mode is selected based on `set_mode` parameter. + bool SetFromString(absl::string_view value, + flags_internal::FlagSettingMode set_mode, + flags_internal::ValueSource source, std::string* error); + + // Constant configuration for a particular flag. + private: + const char* const name; + const HelpText help; + const char* const filename; + + public: + const FlagOpFn op; // Type-specific handler + const FlagMarshallingOpFn marshalling_op; // Marshalling ops handler + const InitialValGenFunc make_init_value; // Makes initial value for the flag + const bool retired; // Is the flag retired? + std::atomic<bool> inited; // fields have been lazily initialized + + // Mutable state (guarded by locks->primary_mu). + bool modified; // Has flag value been modified? + bool on_command_line; // Specified on command line. + bool (*validator)(); // Validator function, or nullptr + FlagCallback callback; // Mutation callback, or nullptr + void* def; // Lazily initialized pointer to default value + void* cur; // Lazily initialized pointer to current value + int64_t counter; // Mutation counter + + // For some types, a copy of the current value is kept in an atomically + // accessible field. + static const int64_t kAtomicInit = 0xababababababababll; + std::atomic<int64_t> atomic; + + // Lazily initialized mutexes for this flag value. We cannot inline a + // SpinLock or Mutex here because those have non-constexpr constructors and + // so would prevent constant initialization of this type. + // TODO(rogeeff): fix it once Mutex has constexpr constructor + struct CommandLineFlagLocks* locks; // locks, laziliy allocated. + + // copy construct new value of flag's type in a memory referenced by dst + // based on current flag's value + void Read(void* dst, const flags_internal::FlagOpFn dst_op) const; + // updates flag's value to *src (locked) + void Write(const void* src, const flags_internal::FlagOpFn src_op); + + ABSL_DEPRECATED( + "temporary until FlagName call sites are migrated and validator API is " + "changed") + const char* NameAsCString() const { return name; } + + private: + friend class FlagRegistry; +}; + +// Ensure that the lazily initialized fields of *flag have been initialized, +// and return &flag->locks->primary_mu. +absl::Mutex* InitFlagIfNecessary(CommandLineFlag* flag); +// Update any copy of the flag value that is stored in an atomic word. +// In addition if flag has a mutation callback this function invokes it. While +// callback is being invoked the primary flag's mutex is unlocked and it is +// re-locked back after call to callback is completed. Callback invocation is +// guarded by flag's secondary mutex instead which prevents concurrent callback +// invocation. Note that it is possible for other thread to grab the primary +// lock and update flag's value at any time during the callback invocation. +// This is by design. Callback can get a value of the flag if necessary, but it +// might be different from the value initiated the callback and it also can be +// different by the time the callback invocation is completed. +// Requires that *primary_lock be held in exclusive mode; it may be released +// and reacquired by the implementation. +void UpdateCopy(CommandLineFlag* flag, absl::Mutex* primary_lock); +// Return true iff flag value was changed via direct-access. +bool ChangedDirectly(CommandLineFlag* flag, const void* a, const void* b); +// Direct-access flags can be modified without going through the +// flag API. Detect such changes and updated the modified bit. +void UpdateModifiedBit(CommandLineFlag* flag); +// Invoke the flag validators for old flags. +// TODO(rogeeff): implement proper validators for Abseil Flags +bool Validate(CommandLineFlag* flag, const void* value); + +// This macro is the "source of truth" for the list of supported flag types we +// expect to perform lock free operations on. Specifically it generates code, +// a one argument macro operating on a type, supplied as a macro argument, for +// each type in the list. +#define ABSL_FLAGS_INTERNAL_FOR_EACH_LOCK_FREE(A) \ + A(bool) \ + A(short) \ + A(unsigned short) \ + A(int) \ + A(unsigned int) \ + A(long) \ + A(unsigned long) \ + A(long long) \ + A(unsigned long long) \ + A(double) \ + A(float) + +} // namespace flags_internal +} // namespace absl + +#endif // ABSL_FLAGS_INTERNAL_COMMANDLINEFLAG_H_ diff --git a/absl/flags/internal/commandlineflag_test.cc b/absl/flags/internal/commandlineflag_test.cc new file mode 100644 index 000000000000..705f301ce7a0 --- /dev/null +++ b/absl/flags/internal/commandlineflag_test.cc @@ -0,0 +1,196 @@ +// +// Copyright 2019 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#include "absl/flags/internal/commandlineflag.h" + +#include "gtest/gtest.h" +#include "absl/flags/flag.h" +#include "absl/flags/internal/registry.h" +#include "absl/memory/memory.h" +#include "absl/strings/match.h" +#include "absl/strings/str_cat.h" + +ABSL_FLAG(int, int_flag, 201, "int_flag help"); +ABSL_FLAG(std::string, string_flag, "dflt", + absl::StrCat("string_flag", " help")); +ABSL_RETIRED_FLAG(bool, bool_retired_flag, false, "bool_retired_flag help"); + +namespace { + +namespace flags = absl::flags_internal; + +class CommandLineFlagTest : public testing::Test { + protected: + void SetUp() override { flag_saver_ = absl::make_unique<flags::FlagSaver>(); } + void TearDown() override { flag_saver_.reset(); } + + private: + std::unique_ptr<flags::FlagSaver> flag_saver_; +}; + +TEST_F(CommandLineFlagTest, TestAttributesAccessMethods) { + auto* flag_01 = flags::FindCommandLineFlag("int_flag"); + + ASSERT_TRUE(flag_01); + EXPECT_EQ(flag_01->Name(), "int_flag"); + EXPECT_EQ(flag_01->Help(), "int_flag help"); + EXPECT_EQ(flag_01->Typename(), ""); + EXPECT_TRUE(!flag_01->IsRetired()); + EXPECT_TRUE(flag_01->IsOfType<int>()); + EXPECT_TRUE(absl::EndsWith( + flag_01->Filename(), + "absl/flags/internal/commandlineflag_test.cc")); + + auto* flag_02 = flags::FindCommandLineFlag("string_flag"); + + ASSERT_TRUE(flag_02); + EXPECT_EQ(flag_02->Name(), "string_flag"); + EXPECT_EQ(flag_02->Help(), "string_flag help"); + EXPECT_EQ(flag_02->Typename(), ""); + EXPECT_TRUE(!flag_02->IsRetired()); + EXPECT_TRUE(flag_02->IsOfType<std::string>()); + EXPECT_TRUE(absl::EndsWith( + flag_02->Filename(), + "absl/flags/internal/commandlineflag_test.cc")); + + auto* flag_03 = flags::FindRetiredFlag("bool_retired_flag"); + + ASSERT_TRUE(flag_03); + EXPECT_EQ(flag_03->Name(), "bool_retired_flag"); + EXPECT_EQ(flag_03->Help(), ""); + EXPECT_EQ(flag_03->Typename(), ""); + EXPECT_TRUE(flag_03->IsRetired()); + EXPECT_TRUE(flag_03->IsOfType<bool>()); + EXPECT_EQ(flag_03->Filename(), "RETIRED"); +} + +// -------------------------------------------------------------------- + +TEST_F(CommandLineFlagTest, TestValueAccessMethods) { + absl::SetFlag(&FLAGS_int_flag, 301); + auto* flag_01 = flags::FindCommandLineFlag("int_flag"); + + ASSERT_TRUE(flag_01); + EXPECT_EQ(flag_01->CurrentValue(), "301"); + EXPECT_EQ(flag_01->DefaultValue(), "201"); + + absl::SetFlag(&FLAGS_string_flag, "new_str_value"); + auto* flag_02 = flags::FindCommandLineFlag("string_flag"); + + ASSERT_TRUE(flag_02); + EXPECT_EQ(flag_02->CurrentValue(), "new_str_value"); + EXPECT_EQ(flag_02->DefaultValue(), "dflt"); +} + +// -------------------------------------------------------------------- + +TEST_F(CommandLineFlagTest, TestSetFromStringCurrentValue) { + std::string err; + + auto* flag_01 = flags::FindCommandLineFlag("int_flag"); + EXPECT_FALSE(flag_01->on_command_line); + + EXPECT_TRUE(flag_01->SetFromString("11", flags::SET_FLAGS_VALUE, + flags::kProgrammaticChange, &err)); + EXPECT_EQ(absl::GetFlag(FLAGS_int_flag), 11); + EXPECT_FALSE(flag_01->on_command_line); + + EXPECT_TRUE(flag_01->SetFromString("-123", flags::SET_FLAGS_VALUE, + flags::kProgrammaticChange, &err)); + EXPECT_EQ(absl::GetFlag(FLAGS_int_flag), -123); + EXPECT_FALSE(flag_01->on_command_line); + + EXPECT_TRUE(!flag_01->SetFromString("xyz", flags::SET_FLAGS_VALUE, + flags::kProgrammaticChange, &err)); + EXPECT_EQ(absl::GetFlag(FLAGS_int_flag), -123); + EXPECT_EQ(err, "Illegal value 'xyz' specified for flag 'int_flag'"); + EXPECT_FALSE(flag_01->on_command_line); + + EXPECT_TRUE(!flag_01->SetFromString("A1", flags::SET_FLAGS_VALUE, + flags::kProgrammaticChange, &err)); + EXPECT_EQ(absl::GetFlag(FLAGS_int_flag), -123); + EXPECT_EQ(err, "Illegal value 'A1' specified for flag 'int_flag'"); + EXPECT_FALSE(flag_01->on_command_line); + + EXPECT_TRUE(flag_01->SetFromString("0x10", flags::SET_FLAGS_VALUE, + flags::kProgrammaticChange, &err)); + EXPECT_EQ(absl::GetFlag(FLAGS_int_flag), 16); + EXPECT_FALSE(flag_01->on_command_line); + + EXPECT_TRUE(flag_01->SetFromString("011", flags::SET_FLAGS_VALUE, + flags::kCommandLine, &err)); + EXPECT_EQ(absl::GetFlag(FLAGS_int_flag), 11); + EXPECT_TRUE(flag_01->on_command_line); + + EXPECT_TRUE(!flag_01->SetFromString("", flags::SET_FLAGS_VALUE, + flags::kProgrammaticChange, &err)); + EXPECT_EQ(err, "Illegal value '' specified for flag 'int_flag'"); + + auto* flag_02 = flags::FindCommandLineFlag("string_flag"); + EXPECT_TRUE(flag_02->SetFromString("xyz", flags::SET_FLAGS_VALUE, + flags::kProgrammaticChange, &err)); + EXPECT_EQ(absl::GetFlag(FLAGS_string_flag), "xyz"); + + EXPECT_TRUE(flag_02->SetFromString("", flags::SET_FLAGS_VALUE, + flags::kProgrammaticChange, &err)); + EXPECT_EQ(absl::GetFlag(FLAGS_string_flag), ""); +} + +// -------------------------------------------------------------------- + +TEST_F(CommandLineFlagTest, TestSetFromStringDefaultValue) { + std::string err; + + auto* flag_01 = flags::FindCommandLineFlag("int_flag"); + + EXPECT_TRUE(flag_01->SetFromString("111", flags::SET_FLAGS_DEFAULT, + flags::kProgrammaticChange, &err)); + EXPECT_EQ(flag_01->DefaultValue(), "111"); + + auto* flag_02 = flags::FindCommandLineFlag("string_flag"); + + EXPECT_TRUE(flag_02->SetFromString("abc", flags::SET_FLAGS_DEFAULT, + flags::kProgrammaticChange, &err)); + EXPECT_EQ(flag_02->DefaultValue(), "abc"); +} + +// -------------------------------------------------------------------- + +TEST_F(CommandLineFlagTest, TestSetFromStringIfDefault) { + std::string err; + + auto* flag_01 = flags::FindCommandLineFlag("int_flag"); + + EXPECT_TRUE(flag_01->SetFromString("22", flags::SET_FLAG_IF_DEFAULT, + flags::kProgrammaticChange, &err)) + << err; + EXPECT_EQ(absl::GetFlag(FLAGS_int_flag), 22); + + EXPECT_TRUE(flag_01->SetFromString("33", flags::SET_FLAG_IF_DEFAULT, + flags::kProgrammaticChange, &err)); + EXPECT_EQ(absl::GetFlag(FLAGS_int_flag), 22); + // EXPECT_EQ(err, "ERROR: int_flag is already set to 22"); + + // Reset back to default value + EXPECT_TRUE(flag_01->SetFromString("201", flags::SET_FLAGS_VALUE, + flags::kProgrammaticChange, &err)); + + EXPECT_TRUE(flag_01->SetFromString("33", flags::SET_FLAG_IF_DEFAULT, + flags::kProgrammaticChange, &err)); + EXPECT_EQ(absl::GetFlag(FLAGS_int_flag), 201); + // EXPECT_EQ(err, "ERROR: int_flag is already set to 201"); +} + +} // namespace diff --git a/absl/flags/internal/flag.h b/absl/flags/internal/flag.h new file mode 100644 index 000000000000..6402866f2249 --- /dev/null +++ b/absl/flags/internal/flag.h @@ -0,0 +1,103 @@ +// +// Copyright 2019 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#ifndef ABSL_FLAGS_INTERNAL_FLAG_H_ +#define ABSL_FLAGS_INTERNAL_FLAG_H_ + +#include "absl/flags/internal/commandlineflag.h" +#include "absl/flags/internal/registry.h" + +namespace absl { +namespace flags_internal { + +// This is "unspecified" implementation of absl::Flag<T> type. +template <typename T> +class Flag { + public: + constexpr Flag(const char* name, const flags_internal::HelpGenFunc help_gen, + const char* filename, + const flags_internal::FlagMarshallingOpFn marshalling_op, + const flags_internal::InitialValGenFunc initial_value_gen) + : internal(name, flags_internal::HelpText::FromFunctionPointer(help_gen), + filename, &flags_internal::FlagOps<T>, marshalling_op, + initial_value_gen, + /*retired_arg=*/false, /*def_arg=*/nullptr, + /*cur_arg=*/nullptr) {} + + // Not copyable/assignable. + Flag(const Flag<T>&) = delete; + Flag<T>& operator=(const Flag<T>&) = delete; + + absl::string_view Name() const { return internal.Name(); } + std::string Help() const { return internal.Help(); } + std::string Filename() const { return internal.Filename(); } + + absl::flags_internal::CommandLineFlag internal; + + void SetCallback(const flags_internal::FlagCallback mutation_callback) { + internal.SetCallback(mutation_callback); + } + + private: + // TODO(rogeeff): add these validations once UnparseFlag invocation is fixed + // for built-in types and when we cleanup existing code from operating on + // forward declared types. + // auto IsCopyConstructible(const T& v) -> decltype(T(v)); + // auto HasAbslParseFlag(absl::string_view in, T* dst, std::string* err) + // -> decltype(AbslParseFlag(in, dst, GlobalStringADLGuard(err))); + // auto HasAbslUnparseFlag(const T& v) -> decltype(AbslUnparseFlag(v)); +}; + +// This class facilitates Flag object registration and tail expression-based +// flag definition, for example: +// ABSL_FLAG(int, foo, 42, "Foo help").OnUpdate(NotifyFooWatcher); +template <typename T, bool do_register> +class FlagRegistrar { + public: + explicit FlagRegistrar(Flag<T>* flag) : flag_(flag) { + if (do_register) flags_internal::RegisterCommandLineFlag(&flag_->internal); + } + + FlagRegistrar& OnUpdate(flags_internal::FlagCallback cb) && { + flag_->SetCallback(cb); + return *this; + } + + // Make the registrar "die" gracefully as a bool on a line where registration + // happens. Registrar objects are intended to live only as temporary. + operator bool() const { return true; } // NOLINT + + private: + Flag<T>* flag_; // Flag being registered (not owned). +}; + +// This struct and corresponding overload to MakeDefaultValue are used to +// facilitate usage of {} as default value in ABSL_FLAG macro. +struct EmptyBraces {}; + +template <typename T> +T* MakeFromDefaultValue(T t) { + return new T(std::move(t)); +} + +template <typename T> +T* MakeFromDefaultValue(EmptyBraces) { + return new T; +} + +} // namespace flags_internal +} // namespace absl + +#endif // ABSL_FLAGS_INTERNAL_FLAG_H_ diff --git a/absl/flags/internal/parse.h b/absl/flags/internal/parse.h new file mode 100644 index 000000000000..fd3aca61f408 --- /dev/null +++ b/absl/flags/internal/parse.h @@ -0,0 +1,48 @@ +// +// Copyright 2019 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#ifndef ABSL_FLAGS_INTERNAL_PARSE_H_ +#define ABSL_FLAGS_INTERNAL_PARSE_H_ + +#include <string> +#include <vector> + +#include "absl/flags/declare.h" + +ABSL_DECLARE_FLAG(std::vector<std::string>, flagfile); +ABSL_DECLARE_FLAG(std::vector<std::string>, fromenv); +ABSL_DECLARE_FLAG(std::vector<std::string>, tryfromenv); +ABSL_DECLARE_FLAG(std::vector<std::string>, undefok); + +namespace absl { +namespace flags_internal { + +enum class ArgvListAction { kRemoveParsedArgs, kKeepParsedArgs }; +enum class UsageFlagsAction { kHandleUsage, kIgnoreUsage }; +enum class OnUndefinedFlag { + kIgnoreUndefined, + kReportUndefined, + kAbortIfUndefined +}; + +std::vector<char*> ParseCommandLineImpl(int argc, char* argv[], + ArgvListAction arg_list_act, + UsageFlagsAction usage_flag_act, + OnUndefinedFlag on_undef_flag); + +} // namespace flags_internal +} // namespace absl + +#endif // ABSL_FLAGS_INTERNAL_PARSE_H_ diff --git a/absl/flags/internal/path_util.h b/absl/flags/internal/path_util.h new file mode 100644 index 000000000000..5615c0e6c590 --- /dev/null +++ b/absl/flags/internal/path_util.h @@ -0,0 +1,60 @@ +// +// Copyright 2019 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#ifndef ABSL_FLAGS_INTERNAL_PATH_UTIL_H_ +#define ABSL_FLAGS_INTERNAL_PATH_UTIL_H_ + +#include "absl/strings/match.h" +#include "absl/strings/string_view.h" + +namespace absl { +namespace flags_internal { + +// A portable interface that returns the basename of the filename passed as an +// argument. It is similar to basename(3) +// <https://linux.die.net/man/3/basename>. +// For example: +// flags_internal::Basename("a/b/prog/file.cc") +// returns "file.cc" +// flags_internal::Basename("file.cc") +// returns "file.cc" +inline absl::string_view Basename(absl::string_view filename) { + auto last_slash_pos = filename.find_last_of("/\\"); + + return last_slash_pos == absl::string_view::npos + ? filename + : filename.substr(last_slash_pos + 1); +} + +// A portable interface that returns the directory name of the filename +// passed as an argument, including the trailing slash. +// Returns the empty string if a slash is not found in the input file name. +// For example: +// flags_internal::Package("a/b/prog/file.cc") +// returns "a/b/prog/" +// flags_internal::Package("file.cc") +// returns "" +inline absl::string_view Package(absl::string_view filename) { + auto last_slash_pos = filename.find_last_of("/\\"); + + return last_slash_pos == absl::string_view::npos + ? absl::string_view() + : filename.substr(0, last_slash_pos + 1); +} + +} // namespace flags_internal +} // namespace absl + +#endif // ABSL_FLAGS_INTERNAL_PATH_UTIL_H_ diff --git a/absl/flags/internal/path_util_test.cc b/absl/flags/internal/path_util_test.cc new file mode 100644 index 000000000000..2091373c88ea --- /dev/null +++ b/absl/flags/internal/path_util_test.cc @@ -0,0 +1,46 @@ +// +// Copyright 2019 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#include "absl/flags/internal/path_util.h" + +#include "gtest/gtest.h" + +namespace { + +namespace flags = absl::flags_internal; + +TEST(FlagsPathUtilTest, TestBasename) { + EXPECT_EQ(flags::Basename(""), ""); + EXPECT_EQ(flags::Basename("a.cc"), "a.cc"); + EXPECT_EQ(flags::Basename("dir/a.cc"), "a.cc"); + EXPECT_EQ(flags::Basename("dir1/dir2/a.cc"), "a.cc"); + EXPECT_EQ(flags::Basename("../dir1/dir2/a.cc"), "a.cc"); + EXPECT_EQ(flags::Basename("/dir1/dir2/a.cc"), "a.cc"); + EXPECT_EQ(flags::Basename("/dir1/dir2/../dir3/a.cc"), "a.cc"); +} + +// -------------------------------------------------------------------- + +TEST(FlagsPathUtilTest, TestPackage) { + EXPECT_EQ(flags::Package(""), ""); + EXPECT_EQ(flags::Package("a.cc"), ""); + EXPECT_EQ(flags::Package("dir/a.cc"), "dir/"); + EXPECT_EQ(flags::Package("dir1/dir2/a.cc"), "dir1/dir2/"); + EXPECT_EQ(flags::Package("../dir1/dir2/a.cc"), "../dir1/dir2/"); + EXPECT_EQ(flags::Package("/dir1/dir2/a.cc"), "/dir1/dir2/"); + EXPECT_EQ(flags::Package("/dir1/dir2/../dir3/a.cc"), "/dir1/dir2/../dir3/"); +} + +} // namespace diff --git a/absl/flags/internal/program_name.cc b/absl/flags/internal/program_name.cc new file mode 100644 index 000000000000..62be645a96ca --- /dev/null +++ b/absl/flags/internal/program_name.cc @@ -0,0 +1,53 @@ +// +// Copyright 2019 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#include "absl/flags/internal/program_name.h" + +#include <string> + +#include "absl/flags/internal/path_util.h" +#include "absl/synchronization/mutex.h" + +namespace absl { +namespace flags_internal { + +ABSL_CONST_INIT static absl::Mutex program_name_guard(absl::kConstInit); +ABSL_CONST_INIT static std::string* program_name + GUARDED_BY(program_name_guard) = nullptr; + +std::string ProgramInvocationName() { + absl::MutexLock l(&program_name_guard); + + return program_name ? *program_name : "UNKNOWN"; +} + +std::string ShortProgramInvocationName() { + absl::MutexLock l(&program_name_guard); + + return program_name ? std::string(flags_internal::Basename(*program_name)) + : "UNKNOWN"; +} + +void SetProgramInvocationName(absl::string_view prog_name_str) { + absl::MutexLock l(&program_name_guard); + + if (!program_name) + program_name = new std::string(prog_name_str); + else + program_name->assign(prog_name_str.data(), prog_name_str.size()); +} + +} // namespace flags_internal +} // namespace absl diff --git a/absl/flags/internal/program_name.h b/absl/flags/internal/program_name.h new file mode 100644 index 000000000000..326f24bb6533 --- /dev/null +++ b/absl/flags/internal/program_name.h @@ -0,0 +1,47 @@ +// +// Copyright 2019 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#ifndef ABSL_FLAGS_INTERNAL_PROGRAM_NAME_H_ +#define ABSL_FLAGS_INTERNAL_PROGRAM_NAME_H_ + +#include <string> + +#include "absl/strings/string_view.h" + +// -------------------------------------------------------------------- +// Program name + +namespace absl { +namespace flags_internal { + +// Returns program invocation name or "UNKNOWN" if `SetProgramInvocationName()` +// is never called. At the moment this is always set to argv[0] as part of +// library initialization. +std::string ProgramInvocationName(); + +// Returns base name for program invocation name. For example, if +// ProgramInvocationName() == "a/b/mybinary" +// then +// ShortProgramInvocationName() == "mybinary" +std::string ShortProgramInvocationName(); + +// Sets program invocation name to a new value. Should only be called once +// during program initialization, before any threads are spawned. +void SetProgramInvocationName(absl::string_view prog_name_str); + +} // namespace flags_internal +} // namespace absl + +#endif // ABSL_FLAGS_INTERNAL_PROGRAM_NAME_H_ diff --git a/absl/flags/internal/program_name_test.cc b/absl/flags/internal/program_name_test.cc new file mode 100644 index 000000000000..ed69218b8395 --- /dev/null +++ b/absl/flags/internal/program_name_test.cc @@ -0,0 +1,60 @@ +// +// Copyright 2019 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#include "absl/flags/internal/program_name.h" + +#include "gtest/gtest.h" +#include "absl/strings/match.h" + +namespace { + +namespace flags = absl::flags_internal; + +TEST(FlagsPathUtilTest, TestInitialProgamName) { + flags::SetProgramInvocationName("absl/flags/program_name_test"); + std::string program_name = flags::ProgramInvocationName(); + for (char& c : program_name) + if (c == '\\') c = '/'; + +#if !defined(__wasm__) && !defined(__asmjs__) + const std::string expect_name = "absl/flags/program_name_test"; + const std::string expect_basename = "program_name_test"; +#else + // For targets that generate javascript or webassembly the invocation name + // has the special value below. + const std::string expect_name = "this.program"; + const std::string expect_basename = "this.program"; +#endif + + EXPECT_TRUE(absl::EndsWith(program_name, expect_name)) << program_name; + EXPECT_EQ(flags::ShortProgramInvocationName(), expect_basename); +} + +TEST(FlagsPathUtilTest, TestProgamNameInterfaces) { + flags::SetProgramInvocationName("a/my_test"); + + EXPECT_EQ(flags::ProgramInvocationName(), "a/my_test"); + EXPECT_EQ(flags::ShortProgramInvocationName(), "my_test"); + + absl::string_view not_null_terminated("absl/aaa/bbb"); + not_null_terminated = not_null_terminated.substr(1, 10); + + flags::SetProgramInvocationName(not_null_terminated); + + EXPECT_EQ(flags::ProgramInvocationName(), "bsl/aaa/bb"); + EXPECT_EQ(flags::ShortProgramInvocationName(), "bb"); +} + +} // namespace diff --git a/absl/flags/internal/registry.cc b/absl/flags/internal/registry.cc new file mode 100644 index 000000000000..435c5b0be330 --- /dev/null +++ b/absl/flags/internal/registry.cc @@ -0,0 +1,529 @@ +// +// Copyright 2019 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#include "absl/flags/internal/registry.h" + +#include "absl/base/call_once.h" +#include "absl/base/dynamic_annotations.h" +#include "absl/base/internal/raw_logging.h" +#include "absl/flags/config.h" +#include "absl/flags/usage_config.h" +#include "absl/strings/str_cat.h" +#include "absl/strings/string_view.h" +#include "absl/synchronization/mutex.h" + +// -------------------------------------------------------------------- +// FlagRegistry implementation +// A FlagRegistry holds all flag objects indexed +// by their names so that if you know a flag's name you can access or +// set it. + +namespace absl { +namespace flags_internal { +namespace { + +void DestroyFlag(CommandLineFlag* flag) NO_THREAD_SAFETY_ANALYSIS { + // Values are heap allocated for retired and Abseil Flags. + if (flag->IsRetired() || flag->IsAbseilFlag()) { + if (flag->cur) Delete(flag->op, flag->cur); + if (flag->def) Delete(flag->op, flag->def); + } + + delete flag->locks; + + // CommandLineFlag handle object is heap allocated for non Abseil Flags. + if (!flag->IsAbseilFlag()) { + delete flag; + } +} + +// -------------------------------------------------------------------- +// FlagRegistry +// A FlagRegistry singleton object holds all flag objects indexed +// by their names so that if you know a flag's name (as a C +// string), you can access or set it. If the function is named +// FooLocked(), you must own the registry lock before calling +// the function; otherwise, you should *not* hold the lock, and +// the function will acquire it itself if needed. +// -------------------------------------------------------------------- + +// A map from flag pointer to CommandLineFlag*. Used when registering +// validators. +class FlagPtrMap { + public: + void Register(CommandLineFlag* flag) { + auto& vec = buckets_[BucketForFlag(flag->cur)]; + if (vec.size() == vec.capacity()) { + // Bypass default 2x growth factor with 1.25 so we have fuller vectors. + // This saves 4% memory compared to default growth. + vec.reserve(vec.size() * 1.25 + 0.5); + } + vec.push_back(flag); + } + + CommandLineFlag* FindByPtr(const void* flag_ptr) { + const auto& flag_vector = buckets_[BucketForFlag(flag_ptr)]; + for (CommandLineFlag* entry : flag_vector) { + if (entry->cur == flag_ptr) { + return entry; + } + } + return nullptr; + } + + private: + // Instead of std::map, we use a custom hash table where each bucket stores + // flags in a vector. This reduces memory usage 40% of the memory that would + // have been used by std::map. + // + // kNumBuckets was picked as a large enough prime. As of writing this code, a + // typical large binary has ~8k (old-style) flags, and this would gives + // buckets with roughly 50 elements each. + // + // Note that reads to this hash table are rare: exactly as many as we have + // flags with validators. As of writing, a typical binary only registers 52 + // validated flags. + static constexpr size_t kNumBuckets = 163; + std::vector<CommandLineFlag*> buckets_[kNumBuckets]; + + static int BucketForFlag(const void* ptr) { + // Modulo a prime is good enough here. On a real program, bucket size stddev + // after registering 8k flags is ~5 (mean size at 51). + return reinterpret_cast<uintptr_t>(ptr) % kNumBuckets; + } +}; +constexpr size_t FlagPtrMap::kNumBuckets; + +} // namespace + +class FlagRegistry { + public: + FlagRegistry() = default; + ~FlagRegistry() { + for (auto& p : flags_) { + DestroyFlag(p.second); + } + } + + // Store a flag in this registry. Takes ownership of *flag. + // If ptr is non-null, the flag can later be found by calling + // FindFlagViaPtrLocked(ptr). + void RegisterFlag(CommandLineFlag* flag, const void* ptr); + + void Lock() EXCLUSIVE_LOCK_FUNCTION(lock_) { lock_.Lock(); } + void Unlock() UNLOCK_FUNCTION(lock_) { lock_.Unlock(); } + + // Returns the flag object for the specified name, or nullptr if not found. + // Will emit a warning if a 'retired' flag is specified. + CommandLineFlag* FindFlagLocked(absl::string_view name); + + // Returns the retired flag object for the specified name, or nullptr if not + // found or not retired. Does not emit a warning. + CommandLineFlag* FindRetiredFlagLocked(absl::string_view name); + + // Returns the flag object whose current-value is stored at flag_ptr. + CommandLineFlag* FindFlagViaPtrLocked(const void* flag_ptr); + + static FlagRegistry* GlobalRegistry(); // returns a singleton registry + + private: + friend class FlagSaverImpl; // reads all the flags in order to copy them + friend void ForEachFlagUnlocked( + std::function<void(CommandLineFlag*)> visitor); + + // The map from name to flag, for FindFlagLocked(). + using FlagMap = std::map<absl::string_view, CommandLineFlag*>; + using FlagIterator = FlagMap::iterator; + using FlagConstIterator = FlagMap::const_iterator; + FlagMap flags_; + + FlagPtrMap flag_ptr_map_; + + static FlagRegistry* global_registry_; // a singleton registry + + static absl::once_flag global_registry_once_; + + static void InitGlobalRegistry(); + + absl::Mutex lock_; + + // Disallow + FlagRegistry(const FlagRegistry&); + FlagRegistry& operator=(const FlagRegistry&); +}; + +// Get the singleton FlagRegistry object +FlagRegistry* FlagRegistry::global_registry_ = nullptr; +absl::once_flag FlagRegistry::global_registry_once_; + +void FlagRegistry::InitGlobalRegistry() { global_registry_ = new FlagRegistry; } + +FlagRegistry* FlagRegistry::GlobalRegistry() { + absl::call_once(global_registry_once_, &InitGlobalRegistry); + + return global_registry_; +} + +namespace { + +class FlagRegistryLock { + public: + explicit FlagRegistryLock(FlagRegistry* fr) : fr_(fr) { fr_->Lock(); } + ~FlagRegistryLock() { fr_->Unlock(); } + + private: + FlagRegistry* const fr_; +}; + +} // namespace + +void FlagRegistry::RegisterFlag(CommandLineFlag* flag, const void* ptr) { + FlagRegistryLock registry_lock(this); + std::pair<FlagIterator, bool> ins = + flags_.insert(FlagMap::value_type(flag->Name(), flag)); + if (ins.second == false) { // means the name was already in the map + CommandLineFlag* old_flag = ins.first->second; + if (flag->IsRetired() != old_flag->IsRetired()) { + // All registrations must agree on the 'retired' flag. + flags_internal::ReportUsageError( + absl::StrCat( + "Retired flag '", flag->Name(), + "' was defined normally in file '", + (flag->IsRetired() ? old_flag->Filename() : flag->Filename()), + "'."), + true); + } else if (flag->op != old_flag->op) { + flags_internal::ReportUsageError( + absl::StrCat("Flag '", flag->Name(), + "' was defined more than once but with " + "differing types. Defined in files '", + old_flag->Filename(), "' and '", flag->Filename(), + "' with types '", old_flag->Typename(), "' and '", + flag->Typename(), "', respectively."), + true); + } else if (old_flag->IsRetired()) { + // Retired definitions are idempotent. Just keep the old one. + DestroyFlag(flag); + return; + } else if (old_flag->Filename() != flag->Filename()) { + flags_internal::ReportUsageError( + absl::StrCat("Flag '", flag->Name(), + "' was defined more than once (in files '", + old_flag->Filename(), "' and '", flag->Filename(), + "')."), + true); + } else { + flags_internal::ReportUsageError( + absl::StrCat( + "Something wrong with flag '", flag->Name(), "' in file '", + flag->Filename(), "'. One possibility: file '", flag->Filename(), + "' is being linked both statically and dynamically into this " + "executable. e.g. some files listed as srcs to a test and also " + "listed as srcs of some shared lib deps of the same test."), + true); + } + // All cases above are fatal, except for the retired flags. + std::exit(1); + } + + if (ptr != nullptr) { + // This must be the first time we're seeing this flag. + flag_ptr_map_.Register(flag); + } +} + +CommandLineFlag* FlagRegistry::FindFlagLocked(absl::string_view name) { + FlagConstIterator i = flags_.find(name); + if (i == flags_.end()) { + return nullptr; + } + + if (i->second->IsRetired()) { + flags_internal::ReportUsageError( + absl::StrCat("Accessing retired flag '", name, "'"), false); + } + + return i->second; +} + +CommandLineFlag* FlagRegistry::FindRetiredFlagLocked(absl::string_view name) { + FlagConstIterator i = flags_.find(name); + if (i == flags_.end() || !i->second->IsRetired()) { + return nullptr; + } + + return i->second; +} + +CommandLineFlag* FlagRegistry::FindFlagViaPtrLocked(const void* flag_ptr) { + return flag_ptr_map_.FindByPtr(flag_ptr); +} + +// -------------------------------------------------------------------- +// FlagSaver +// FlagSaverImpl +// This class stores the states of all flags at construct time, +// and restores all flags to that state at destruct time. +// Its major implementation challenge is that it never modifies +// pointers in the 'main' registry, so global FLAG_* vars always +// point to the right place. +// -------------------------------------------------------------------- + +class FlagSaverImpl { + public: + // Constructs an empty FlagSaverImpl object. + FlagSaverImpl() {} + ~FlagSaverImpl() { + // reclaim memory from each of our CommandLineFlags + for (const SavedFlag& src : backup_registry_) { + Delete(src.op, src.current); + Delete(src.op, src.default_value); + } + } + + // Saves the flag states from the flag registry into this object. + // It's an error to call this more than once. + // Must be called when the registry mutex is not held. + void SaveFromRegistry() { + assert(backup_registry_.empty()); // call only once! + SavedFlag saved; + flags_internal::ForEachFlag([&](flags_internal::CommandLineFlag* flag) { + if (flag->IsRetired()) return; + + saved.name = flag->Name(); + saved.op = flag->op; + saved.marshalling_op = flag->marshalling_op; + { + absl::MutexLock l(InitFlagIfNecessary(flag)); + saved.validator = flag->validator; + saved.modified = flag->modified; + saved.on_command_line = flag->IsSpecifiedOnCommandLine(); + saved.current = Clone(saved.op, flag->cur); + saved.default_value = Clone(saved.op, flag->def); + saved.counter = flag->counter; + } + backup_registry_.push_back(saved); + }); + } + + // Restores the saved flag states into the flag registry. We + // assume no flags were added or deleted from the registry since + // the SaveFromRegistry; if they were, that's trouble! Must be + // called when the registry mutex is not held. + void RestoreToRegistry() { + FlagRegistry* const global_registry = FlagRegistry::GlobalRegistry(); + FlagRegistryLock frl(global_registry); + for (const SavedFlag& src : backup_registry_) { + CommandLineFlag* flag = global_registry->FindFlagLocked(src.name); + // If null, flag got deleted from registry. + if (!flag) continue; + + bool restored = false; + { + absl::Mutex* mu = InitFlagIfNecessary(flag); + absl::MutexLock l(mu); + flag->validator = src.validator; + flag->modified = src.modified; + flag->on_command_line = src.on_command_line; + if (flag->counter != src.counter || + ChangedDirectly(flag, src.default_value, flag->def)) { + flag->counter++; + Copy(src.op, src.default_value, flag->def); + } + if (flag->counter != src.counter || + ChangedDirectly(flag, src.current, flag->cur)) { + restored = true; + flag->counter++; + Copy(src.op, src.current, flag->cur); + UpdateCopy(flag, mu); + + // Revalidate the flag because the validator might store state based + // on the flag's value, which just changed due to the restore. + // Failing validation is ignored because it's assumed that the flag + // was valid previously and there's little that can be done about it + // here, anyway. + Validate(flag, flag->cur); + } + } + + // Log statements must be done when no flag lock is held. + if (restored) { + ABSL_INTERNAL_LOG( + INFO, absl::StrCat("Restore saved value of ", flag->Name(), ": ", + Unparse(src.marshalling_op, src.current))); + } + } + } + + private: + struct SavedFlag { + absl::string_view name; + FlagOpFn op; + FlagMarshallingOpFn marshalling_op; + int64_t counter; + bool modified; + bool on_command_line; + bool (*validator)(); + const void* current; // nullptr after restore + const void* default_value; // nullptr after restore + }; + + std::vector<SavedFlag> backup_registry_; + + FlagSaverImpl(const FlagSaverImpl&); // no copying! + void operator=(const FlagSaverImpl&); +}; + +FlagSaver::FlagSaver() : impl_(new FlagSaverImpl()) { + impl_->SaveFromRegistry(); +} + +void FlagSaver::Ignore() { + delete impl_; + impl_ = nullptr; +} + +FlagSaver::~FlagSaver() { + if (!impl_) return; + + impl_->RestoreToRegistry(); + delete impl_; +} + +// -------------------------------------------------------------------- +// GetAllFlags() +// The main way the FlagRegistry class exposes its data. This +// returns, as strings, all the info about all the flags in +// the main registry, sorted first by filename they are defined +// in, and then by flagname. +// -------------------------------------------------------------------- + +struct FilenameFlagnameLess { + bool operator()(const CommandLineFlagInfo& a, + const CommandLineFlagInfo& b) const { + int cmp = absl::string_view(a.filename).compare(b.filename); + if (cmp != 0) return cmp < 0; + return a.name < b.name; + } +}; + +void FillCommandLineFlagInfo(CommandLineFlag* flag, + CommandLineFlagInfo* result) { + result->name = std::string(flag->Name()); + result->type = std::string(flag->Typename()); + result->description = flag->Help(); + result->filename = flag->Filename(); + + UpdateModifiedBit(flag); + + absl::MutexLock l(InitFlagIfNecessary(flag)); + result->current_value = flag->CurrentValue(); + result->default_value = flag->DefaultValue(); + result->is_default = !flag->modified; + result->has_validator_fn = (flag->validator != nullptr); + result->flag_ptr = flag->IsAbseilFlag() ? nullptr : flag->cur; +} + +// -------------------------------------------------------------------- + +CommandLineFlag* FindCommandLineFlag(absl::string_view name) { + if (name.empty()) return nullptr; + FlagRegistry* const registry = FlagRegistry::GlobalRegistry(); + FlagRegistryLock frl(registry); + + return registry->FindFlagLocked(name); +} + +CommandLineFlag* FindCommandLineV1Flag(const void* flag_ptr) { + FlagRegistry* const registry = FlagRegistry::GlobalRegistry(); + FlagRegistryLock frl(registry); + + return registry->FindFlagViaPtrLocked(flag_ptr); +} + +CommandLineFlag* FindRetiredFlag(absl::string_view name) { + FlagRegistry* const registry = FlagRegistry::GlobalRegistry(); + FlagRegistryLock frl(registry); + + return registry->FindRetiredFlagLocked(name); +} + +// -------------------------------------------------------------------- + +void ForEachFlagUnlocked(std::function<void(CommandLineFlag*)> visitor) { + FlagRegistry* const registry = FlagRegistry::GlobalRegistry(); + for (FlagRegistry::FlagConstIterator i = registry->flags_.begin(); + i != registry->flags_.end(); ++i) { + visitor(i->second); + } +} + +void ForEachFlag(std::function<void(CommandLineFlag*)> visitor) { + FlagRegistry* const registry = FlagRegistry::GlobalRegistry(); + FlagRegistryLock frl(registry); + ForEachFlagUnlocked(visitor); +} + +// -------------------------------------------------------------------- + +void GetAllFlags(std::vector<CommandLineFlagInfo>* OUTPUT) { + flags_internal::ForEachFlag([&](CommandLineFlag* flag) { + if (flag->IsRetired()) return; + + CommandLineFlagInfo fi; + FillCommandLineFlagInfo(flag, &fi); + OUTPUT->push_back(fi); + }); + + // Now sort the flags, first by filename they occur in, then alphabetically + std::sort(OUTPUT->begin(), OUTPUT->end(), FilenameFlagnameLess()); +} + +// -------------------------------------------------------------------- + +bool RegisterCommandLineFlag(CommandLineFlag* flag, const void* ptr) { + FlagRegistry::GlobalRegistry()->RegisterFlag(flag, ptr); + return true; +} + +// -------------------------------------------------------------------- + +bool Retire(FlagOpFn ops, FlagMarshallingOpFn marshalling_ops, + const char* name) { + auto* flag = new CommandLineFlag( + name, + /*help_text=*/absl::flags_internal::HelpText::FromStaticCString(nullptr), + /*filename_arg=*/"RETIRED", ops, marshalling_ops, + /*initial_value_gen=*/nullptr, + /*retired_arg=*/true, nullptr, nullptr); + FlagRegistry::GlobalRegistry()->RegisterFlag(flag, nullptr); + return true; +} + +// -------------------------------------------------------------------- + +bool IsRetiredFlag(absl::string_view name, bool* type_is_bool) { + assert(!name.empty()); + CommandLineFlag* flag = flags_internal::FindRetiredFlag(name); + if (flag == nullptr) { + return false; + } + assert(type_is_bool); + *type_is_bool = flag->IsOfType<bool>(); + return true; +} + +} // namespace flags_internal +} // namespace absl diff --git a/absl/flags/internal/registry.h b/absl/flags/internal/registry.h new file mode 100644 index 000000000000..bd141e1e23d2 --- /dev/null +++ b/absl/flags/internal/registry.h @@ -0,0 +1,168 @@ +// +// Copyright 2019 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#ifndef ABSL_FLAGS_INTERNAL_REGISTRY_H_ +#define ABSL_FLAGS_INTERNAL_REGISTRY_H_ + +#include <functional> +#include <map> +#include <string> + +#include "absl/base/macros.h" +#include "absl/flags/internal/commandlineflag.h" + +// -------------------------------------------------------------------- +// Global flags registry API. + +namespace absl { +namespace flags_internal { + +// CommandLineFlagInfo holds all information for a flag. +struct CommandLineFlagInfo { + std::string name; // the name of the flag + std::string type; // DO NOT use. Use flag->IsOfType<T>() instead. + std::string description; // the "help text" associated with the flag + std::string current_value; // the current value, as a std::string + std::string default_value; // the default value, as a std::string + std::string filename; // 'cleaned' version of filename holding the flag + bool has_validator_fn; // true if RegisterFlagValidator called on this flag + + bool is_default; // true if the flag has the default value and + // has not been set explicitly from the cmdline + // or via SetCommandLineOption. + + // nullptr for ABSL_FLAG. A pointer to the flag's current value + // otherwise. E.g., for DEFINE_int32(foo, ...), flag_ptr will be + // &FLAGS_foo. + const void* flag_ptr; +}; + +//----------------------------------------------------------------------------- + +void FillCommandLineFlagInfo(CommandLineFlag* flag, + CommandLineFlagInfo* result); + +//----------------------------------------------------------------------------- + +CommandLineFlag* FindCommandLineFlag(absl::string_view name); +CommandLineFlag* FindCommandLineV1Flag(const void* flag_ptr); +CommandLineFlag* FindRetiredFlag(absl::string_view name); + +// Executes specified visitor for each non-retired flag in the registry. +// Requires the caller hold the registry lock. +void ForEachFlagUnlocked(std::function<void(CommandLineFlag*)> visitor); +// Executes specified visitor for each non-retired flag in the registry. While +// callback are executed, the registry is locked and can't be changed. +void ForEachFlag(std::function<void(CommandLineFlag*)> visitor); + +//----------------------------------------------------------------------------- + +// Store the list of all flags in *OUTPUT, sorted by file. +void GetAllFlags(std::vector<CommandLineFlagInfo>* OUTPUT); + +//----------------------------------------------------------------------------- + +bool RegisterCommandLineFlag(CommandLineFlag*, const void* ptr = nullptr); + +//----------------------------------------------------------------------------- +// Retired registrations: +// +// Retired flag registrations are treated specially. A 'retired' flag is +// provided only for compatibility with automated invocations that still +// name it. A 'retired' flag: +// - is not bound to a C++ FLAGS_ reference. +// - has a type and a value, but that value is intentionally inaccessible. +// - does not appear in --help messages. +// - is fully supported by _all_ flag parsing routines. +// - consumes args normally, and complains about type mismatches in its +// argument. +// - emits a complaint but does not die (e.g. LOG(ERROR)) if it is +// accessed by name through the flags API for parsing or otherwise. +// +// The registrations for a flag happen in an unspecified order as the +// initializers for the namespace-scope objects of a program are run. +// Any number of weak registrations for a flag can weakly define the flag. +// One non-weak registration will upgrade the flag from weak to non-weak. +// Further weak registrations of a non-weak flag are ignored. +// +// This mechanism is designed to support moving dead flags into a +// 'graveyard' library. An example migration: +// +// 0: Remove references to this FLAGS_flagname in the C++ codebase. +// 1: Register as 'retired' in old_lib. +// 2: Make old_lib depend on graveyard. +// 3: Add a redundant 'retired' registration to graveyard. +// 4: Remove the old_lib 'retired' registration. +// 5: Eventually delete the graveyard registration entirely. +// +// Returns bool to enable use in namespace-scope initializers. +// For example: +// +// static const bool dummy = base::RetiredFlag<int32_t>("myflag"); +// +// Or to declare several at once: +// +// static bool dummies[] = { +// base::RetiredFlag<std::string>("some_string_flag"), +// base::RetiredFlag<double>("some_double_flag"), +// base::RetiredFlag<int32_t>("some_int32_flag") +// }; + +// Retire flag with name "name" and type indicated by ops. +bool Retire(FlagOpFn ops, FlagMarshallingOpFn marshalling_ops, + const char* name); + +// Registered a retired flag with name 'flag_name' and type 'T'. +template <typename T> +inline bool RetiredFlag(const char* flag_name) { + return flags_internal::Retire(flags_internal::FlagOps<T>, + flags_internal::FlagMarshallingOps<T>, + flag_name); +} + +// If the flag is retired, returns true and indicates in |*type_is_bool| +// whether the type of the retired flag is a bool. +// Only to be called by code that needs to explicitly ignore retired flags. +bool IsRetiredFlag(absl::string_view name, bool* type_is_bool); + +//----------------------------------------------------------------------------- +// Saves the states (value, default value, whether the user has set +// the flag, registered validators, etc) of all flags, and restores +// them when the FlagSaver is destroyed. +// +// This class is thread-safe. However, its destructor writes to +// exactly the set of flags that have changed value during its +// lifetime, so concurrent _direct_ access to those flags +// (i.e. FLAGS_foo instead of {Get,Set}CommandLineOption()) is unsafe. + +class FlagSaver { + public: + FlagSaver(); + ~FlagSaver(); + + FlagSaver(const FlagSaver&) = delete; + void operator=(const FlagSaver&) = delete; + + // Prevents saver from restoring the saved state of flags. + void Ignore(); + + private: + class FlagSaverImpl* impl_; // we use pimpl here to keep API steady +}; + +} // namespace flags_internal +} // namespace absl + +#endif // ABSL_FLAGS_INTERNAL_REGISTRY_H_ diff --git a/absl/flags/internal/type_erased.cc b/absl/flags/internal/type_erased.cc new file mode 100644 index 000000000000..cc103983672b --- /dev/null +++ b/absl/flags/internal/type_erased.cc @@ -0,0 +1,121 @@ +// +// Copyright 2019 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#include "absl/flags/internal/type_erased.h" + +#include "absl/base/internal/raw_logging.h" +#include "absl/flags/config.h" +#include "absl/flags/usage_config.h" +#include "absl/strings/str_cat.h" + +namespace absl { +namespace flags_internal { + +bool GetCommandLineOption(absl::string_view name, std::string* value) { + if (name.empty()) return false; + assert(value); + + CommandLineFlag* flag = flags_internal::FindCommandLineFlag(name); + if (flag == nullptr || flag->IsRetired()) { + return false; + } + + absl::MutexLock l(InitFlagIfNecessary(flag)); + *value = flag->CurrentValue(); + return true; +} + +bool GetCommandLineFlagInfo(absl::string_view name, + CommandLineFlagInfo* OUTPUT) { + if (name.empty()) return false; + + CommandLineFlag* flag = flags_internal::FindCommandLineFlag(name); + if (flag == nullptr || flag->IsRetired()) { + return false; + } + + assert(OUTPUT); + FillCommandLineFlagInfo(flag, OUTPUT); + return true; +} + +CommandLineFlagInfo GetCommandLineFlagInfoOrDie(absl::string_view name) { + CommandLineFlagInfo info; + if (!GetCommandLineFlagInfo(name, &info)) { + ABSL_INTERNAL_LOG(FATAL, absl::StrCat("Flag '", name, "' does not exist")); + } + return info; +} + +// -------------------------------------------------------------------- + +bool SetCommandLineOption(absl::string_view name, absl::string_view value) { + return SetCommandLineOptionWithMode(name, value, + flags_internal::SET_FLAGS_VALUE); +} + +bool SetCommandLineOptionWithMode(absl::string_view name, + absl::string_view value, + FlagSettingMode set_mode) { + CommandLineFlag* flag = flags_internal::FindCommandLineFlag(name); + + if (!flag || flag->IsRetired()) return false; + + std::string error; + if (!flag->SetFromString(value, set_mode, kProgrammaticChange, &error)) { + // Errors here are all of the form: the provided name was a recognized + // flag, but the value was invalid (bad type, or validation failed). + flags_internal::ReportUsageError(error, false); + return false; + } + + return true; +} + +// -------------------------------------------------------------------- + +bool IsValidFlagValue(absl::string_view name, absl::string_view value) { + CommandLineFlag* flag = flags_internal::FindCommandLineFlag(name); + if (flag == nullptr) { + return false; + } + + if (flag->IsRetired()) { + return true; + } + + // No need to lock the flag since we are not mutating it. + void* obj = Clone(flag->op, flag->def); + std::string ignored_error; + const bool result = + flags_internal::Parse(flag->marshalling_op, value, obj, &ignored_error) && + Validate(flag, obj); + Delete(flag->op, obj); + return result; +} + +// -------------------------------------------------------------------- + +bool SpecifiedOnCommandLine(absl::string_view name) { + CommandLineFlag* flag = flags_internal::FindCommandLineFlag(name); + if (flag != nullptr && !flag->IsRetired()) { + absl::MutexLock l(InitFlagIfNecessary(flag)); + return flag->IsSpecifiedOnCommandLine(); + } + return false; +} + +} // namespace flags_internal +} // namespace absl diff --git a/absl/flags/internal/type_erased.h b/absl/flags/internal/type_erased.h new file mode 100644 index 000000000000..249d36b9f33f --- /dev/null +++ b/absl/flags/internal/type_erased.h @@ -0,0 +1,97 @@ +// +// Copyright 2019 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#ifndef ABSL_FLAGS_INTERNAL_TYPE_ERASED_H_ +#define ABSL_FLAGS_INTERNAL_TYPE_ERASED_H_ + +#include <string> + +#include "absl/flags/internal/commandlineflag.h" +#include "absl/flags/internal/registry.h" + +// -------------------------------------------------------------------- +// Registry interfaces operating on type erased handles. + +namespace absl { +namespace flags_internal { + +// If a flag named "name" exists, store its current value in *OUTPUT +// and return true. Else return false without changing *OUTPUT. +// Thread-safe. +bool GetCommandLineOption(absl::string_view name, std::string* value); + +// If a flag named "name" exists, store its information in *OUTPUT +// and return true. Else return false without changing *OUTPUT. +// Thread-safe. +bool GetCommandLineFlagInfo(absl::string_view name, + CommandLineFlagInfo* OUTPUT); + +// Returns the CommandLineFlagInfo of the flagname. exit() with an +// error code if name not found. +// Thread-safe. +CommandLineFlagInfo GetCommandLineFlagInfoOrDie(absl::string_view name); + +// Set the value of the flag named "name" to value. If successful, +// returns true. If not successful (e.g., the flag was not found or +// the value is not a valid value), returns false. +// Thread-safe. +bool SetCommandLineOption(absl::string_view name, absl::string_view value); + +bool SetCommandLineOptionWithMode(absl::string_view name, + absl::string_view value, + FlagSettingMode set_mode); + +//----------------------------------------------------------------------------- + +// Returns true iff all of the following conditions are true: +// (a) "name" names a registered flag +// (b) "value" can be parsed succesfully according to the type of the flag +// (c) parsed value passes any validator associated with the flag +bool IsValidFlagValue(absl::string_view name, absl::string_view value); + +//----------------------------------------------------------------------------- + +// Returns true iff a flag named "name" was specified on the command line +// (either directly, or via one of --flagfile or --fromenv or --tryfromenv). +// +// Any non-command-line modification of the flag does not affect the +// result of this function. So for example, if a flag was passed on +// the command line but then reset via SET_FLAGS_DEFAULT, this +// function will still return true. +bool SpecifiedOnCommandLine(absl::string_view name); + +//----------------------------------------------------------------------------- + +// If a flag with specified "name" exists and has type T, store +// its current value in *dst and return true. Else return false +// without touching *dst. T must obey all of the requirements for +// types passed to DEFINE_FLAG. +template <typename T> +inline bool GetByName(absl::string_view name, T* dst) { + CommandLineFlag* flag = flags_internal::FindCommandLineFlag(name); + if (!flag) return false; + + if (auto val = flag->Get<T>()) { + *dst = *val; + return true; + } + + return false; +} + +} // namespace flags_internal +} // namespace absl + +#endif // ABSL_FLAGS_INTERNAL_TYPE_ERASED_H_ diff --git a/absl/flags/internal/type_erased_test.cc b/absl/flags/internal/type_erased_test.cc new file mode 100644 index 000000000000..ac749a607548 --- /dev/null +++ b/absl/flags/internal/type_erased_test.cc @@ -0,0 +1,147 @@ +// +// Copyright 2019 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#include "absl/flags/internal/type_erased.h" + +#include <cmath> + +#include "gtest/gtest.h" +#include "absl/flags/flag.h" +#include "absl/memory/memory.h" +#include "absl/strings/str_cat.h" + +ABSL_FLAG(int, int_flag, 1, "int_flag help"); +ABSL_FLAG(std::string, string_flag, "dflt", "string_flag help"); +ABSL_RETIRED_FLAG(bool, bool_retired_flag, false, "bool_retired_flag help"); + +namespace { + +namespace flags = absl::flags_internal; + +class TypeErasedTest : public testing::Test { + protected: + void SetUp() override { flag_saver_ = absl::make_unique<flags::FlagSaver>(); } + void TearDown() override { flag_saver_.reset(); } + + private: + std::unique_ptr<flags::FlagSaver> flag_saver_; +}; + +// -------------------------------------------------------------------- + +TEST_F(TypeErasedTest, TestGetCommandLineOption) { + std::string value; + EXPECT_TRUE(flags::GetCommandLineOption("int_flag", &value)); + EXPECT_EQ(value, "1"); + + EXPECT_TRUE(flags::GetCommandLineOption("string_flag", &value)); + EXPECT_EQ(value, "dflt"); + + EXPECT_FALSE(flags::GetCommandLineOption("bool_retired_flag", &value)); + + EXPECT_FALSE(flags::GetCommandLineOption("unknown_flag", &value)); +} + +// -------------------------------------------------------------------- + +TEST_F(TypeErasedTest, TestSetCommandLineOption) { + EXPECT_TRUE(flags::SetCommandLineOption("int_flag", "101")); + EXPECT_EQ(absl::GetFlag(FLAGS_int_flag), 101); + + EXPECT_TRUE(flags::SetCommandLineOption("string_flag", "asdfgh")); + EXPECT_EQ(absl::GetFlag(FLAGS_string_flag), "asdfgh"); + + EXPECT_FALSE(flags::SetCommandLineOption("bool_retired_flag", "true")); + + EXPECT_FALSE(flags::SetCommandLineOption("unknown_flag", "true")); +} + +// -------------------------------------------------------------------- + +TEST_F(TypeErasedTest, TestSetCommandLineOptionWithMode_SET_FLAGS_VALUE) { + EXPECT_TRUE(flags::SetCommandLineOptionWithMode("int_flag", "101", + flags::SET_FLAGS_VALUE)); + EXPECT_EQ(absl::GetFlag(FLAGS_int_flag), 101); + + EXPECT_TRUE(flags::SetCommandLineOptionWithMode("string_flag", "asdfgh", + flags::SET_FLAGS_VALUE)); + EXPECT_EQ(absl::GetFlag(FLAGS_string_flag), "asdfgh"); + + EXPECT_FALSE(flags::SetCommandLineOptionWithMode("bool_retired_flag", "true", + flags::SET_FLAGS_VALUE)); + + EXPECT_FALSE(flags::SetCommandLineOptionWithMode("unknown_flag", "true", + flags::SET_FLAGS_VALUE)); +} + +// -------------------------------------------------------------------- + +TEST_F(TypeErasedTest, TestSetCommandLineOptionWithMode_SET_FLAG_IF_DEFAULT) { + EXPECT_TRUE(flags::SetCommandLineOptionWithMode("int_flag", "101", + flags::SET_FLAG_IF_DEFAULT)); + EXPECT_EQ(absl::GetFlag(FLAGS_int_flag), 101); + + // This semantic is broken. We return true instead of false. Value is not + // updated. + EXPECT_TRUE(flags::SetCommandLineOptionWithMode("int_flag", "202", + flags::SET_FLAG_IF_DEFAULT)); + EXPECT_EQ(absl::GetFlag(FLAGS_int_flag), 101); + + EXPECT_TRUE(flags::SetCommandLineOptionWithMode("string_flag", "asdfgh", + flags::SET_FLAG_IF_DEFAULT)); + EXPECT_EQ(absl::GetFlag(FLAGS_string_flag), "asdfgh"); + + EXPECT_FALSE(flags::SetCommandLineOptionWithMode("bool_retired_flag", "true", + flags::SET_FLAG_IF_DEFAULT)); + + EXPECT_FALSE(flags::SetCommandLineOptionWithMode("unknown_flag", "true", + flags::SET_FLAG_IF_DEFAULT)); +} + +// -------------------------------------------------------------------- + +TEST_F(TypeErasedTest, TestSetCommandLineOptionWithMode_SET_FLAGS_DEFAULT) { + EXPECT_TRUE(flags::SetCommandLineOptionWithMode("int_flag", "101", + flags::SET_FLAGS_DEFAULT)); + + EXPECT_TRUE(flags::SetCommandLineOptionWithMode("string_flag", "asdfgh", + flags::SET_FLAGS_DEFAULT)); + EXPECT_EQ(absl::GetFlag(FLAGS_string_flag), "asdfgh"); + + EXPECT_FALSE(flags::SetCommandLineOptionWithMode("bool_retired_flag", "true", + flags::SET_FLAGS_DEFAULT)); + + EXPECT_FALSE(flags::SetCommandLineOptionWithMode("unknown_flag", "true", + flags::SET_FLAGS_DEFAULT)); + + // This should be successfull, since flag is still is not set + EXPECT_TRUE(flags::SetCommandLineOptionWithMode("int_flag", "202", + flags::SET_FLAG_IF_DEFAULT)); + EXPECT_EQ(absl::GetFlag(FLAGS_int_flag), 202); +} + +// -------------------------------------------------------------------- + +TEST_F(TypeErasedTest, TestIsValidFlagValue) { + EXPECT_TRUE(flags::IsValidFlagValue("int_flag", "57")); + EXPECT_TRUE(flags::IsValidFlagValue("int_flag", "-101")); + EXPECT_FALSE(flags::IsValidFlagValue("int_flag", "1.1")); + + EXPECT_TRUE(flags::IsValidFlagValue("string_flag", "#%^#%^$%DGHDG$W%adsf")); + + EXPECT_TRUE(flags::IsValidFlagValue("bool_retired_flag", "true")); +} + +} // namespace diff --git a/absl/flags/internal/usage.cc b/absl/flags/internal/usage.cc new file mode 100644 index 000000000000..f17cc6c5787d --- /dev/null +++ b/absl/flags/internal/usage.cc @@ -0,0 +1,392 @@ +// +// Copyright 2019 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#include "absl/flags/internal/usage.h" + +#include <map> +#include <string> + +#include "absl/flags/flag.h" +#include "absl/flags/internal/path_util.h" +#include "absl/flags/internal/program_name.h" +#include "absl/flags/usage_config.h" +#include "absl/strings/ascii.h" +#include "absl/strings/str_cat.h" +#include "absl/strings/str_split.h" +#include "absl/synchronization/mutex.h" + +ABSL_FLAG(bool, help, false, + "show help on important flags for this binary [tip: all flags can " + "have two dashes]"); +ABSL_FLAG(bool, helpfull, false, "show help on all flags"); +ABSL_FLAG(bool, helpshort, false, + "show help on only the main module for this program"); +ABSL_FLAG(bool, helppackage, false, + "show help on all modules in the main package"); +ABSL_FLAG(bool, version, false, "show version and build info and exit"); +ABSL_FLAG(bool, only_check_args, false, "exit after checking all flags"); +ABSL_FLAG(std::string, helpon, "", + "show help on the modules named by this flag value"); +ABSL_FLAG(std::string, helpmatch, "", + "show help on modules whose name contains the specified substr"); + +namespace absl { +namespace flags_internal { +namespace { + +// This class is used to emit an XML element with `tag` and `text`. +// It adds opening and closing tags and escapes special characters in the text. +// For example: +// std::cout << XMLElement("title", "Milk & Cookies"); +// prints "<title>Milk & Cookies</title>" +class XMLElement { + public: + XMLElement(absl::string_view tag, absl::string_view txt) + : tag_(tag), txt_(txt) {} + + friend std::ostream& operator<<(std::ostream& out, + const XMLElement& xml_elem) { + out << "<" << xml_elem.tag_ << ">"; + + for (auto c : xml_elem.txt_) { + switch (c) { + case '"': + out << """; + break; + case '\'': + out << "'"; + break; + case '&': + out << "&"; + break; + case '<': + out << "<"; + break; + case '>': + out << ">"; + break; + default: + out << c; + break; + } + } + + return out << "</" << xml_elem.tag_ << ">"; + } + + private: + absl::string_view tag_; + absl::string_view txt_; +}; + +// -------------------------------------------------------------------- +// Helper class to pretty-print info about a flag. + +class FlagHelpPrettyPrinter { + public: + // Pretty printer holds on to the std::ostream& reference to direct an output + // to that stream. + FlagHelpPrettyPrinter(int max_line_len, std::ostream* out) + : out_(*out), + max_line_len_(max_line_len), + line_len_(0), + first_line_(true) {} + + void Write(absl::string_view str, bool wrap_line = false) { + // Empty std::string - do nothing. + if (str.empty()) return; + + std::vector<absl::string_view> tokens; + if (wrap_line) { + tokens = absl::StrSplit(str, absl::ByAnyChar(" \f\n\r\t\v"), + absl::SkipEmpty()); + } else { + tokens.push_back(str); + } + + for (auto token : tokens) { + bool new_line = (line_len_ == 0); + + // Write the token, ending the std::string first if necessary/possible. + if (!new_line && (line_len_ + token.size() >= max_line_len_)) { + EndLine(); + new_line = true; + } + + if (new_line) { + StartLine(); + } else { + out_ << ' '; + ++line_len_; + } + + out_ << token; + line_len_ += token.size(); + } + } + + void StartLine() { + if (first_line_) { + out_ << " "; + line_len_ = 4; + first_line_ = false; + } else { + out_ << " "; + line_len_ = 6; + } + } + void EndLine() { + out_ << '\n'; + line_len_ = 0; + } + + private: + std::ostream& out_; + const int max_line_len_; + int line_len_; + bool first_line_; +}; + +void FlagHelpHumanReadable(const flags_internal::CommandLineFlag& flag, + std::ostream* out) { + FlagHelpPrettyPrinter printer(80, out); // Max line length is 80. + + // Flag name. + printer.Write(absl::StrCat("-", flag.Name())); + + // Flag help. + printer.Write(absl::StrCat("(", flag.Help(), ");"), /*wrap_line=*/true); + + // Flag data type (for V1 flags only). + if (!flag.IsAbseilFlag() && !flag.IsRetired()) { + printer.Write(absl::StrCat("type: ", flag.Typename(), ";")); + } + + // The listed default value will be the actual default from the flag + // definition in the originating source file, unless the value has + // subsequently been modified using SetCommandLineOption() with mode + // SET_FLAGS_DEFAULT. + std::string dflt_val = flag.DefaultValue(); + if (flag.IsOfType<std::string>()) { + dflt_val = absl::StrCat("\"", dflt_val, "\""); + } + printer.Write(absl::StrCat("default: ", dflt_val, ";")); + + if (flag.modified) { + std::string curr_val = flag.CurrentValue(); + if (flag.IsOfType<std::string>()) { + curr_val = absl::StrCat("\"", curr_val, "\""); + } + printer.Write(absl::StrCat("currently: ", curr_val, ";")); + } + + printer.EndLine(); +} + +// Shows help for every filename which matches any of the filters +// If filters are empty, shows help for every file. +// If a flag's help message has been stripped (e.g. by adding '#define +// STRIP_FLAG_HELP 1' then this flag will not be displayed by '--help' +// and its variants. +void FlagsHelpImpl(std::ostream& out, flags_internal::FlagKindFilter filter_cb, + HelpFormat format = HelpFormat::kHumanReadable) { + if (format == HelpFormat::kHumanReadable) { + out << flags_internal::ShortProgramInvocationName() << ": " + << flags_internal::ProgramUsageMessage() << "\n\n"; + } else { + // XML schema is not a part of our public API for now. + out << "<?xml version=\"1.0\"?>\n" + // The document. + << "<AllFlags>\n" + // The program name and usage. + << XMLElement("program", flags_internal::ShortProgramInvocationName()) + << '\n' + << XMLElement("usage", flags_internal::ProgramUsageMessage()) << '\n'; + } + + // Map of package name to + // map of file name to + // vector of flags in the file. + // This map is used to output matching flags grouped by package and file + // name. + std::map<std::string, + std::map<std::string, + std::vector<const flags_internal::CommandLineFlag*>>> + matching_flags; + + flags_internal::ForEachFlag([&](flags_internal::CommandLineFlag* flag) { + absl::MutexLock l(InitFlagIfNecessary(flag)); + + std::string flag_filename = flag->Filename(); + + // Ignore retired flags. + if (flag->IsRetired()) return; + + // If the flag has been stripped, pretend that it doesn't exist. + if (flag->Help() == flags_internal::kStrippedFlagHelp) return; + + // Make sure flag satisfies the filter + if (!filter_cb || !filter_cb(flag_filename)) return; + + matching_flags[std::string(flags_internal::Package(flag_filename))] + [flag_filename] + .push_back(flag); + }); + + absl::string_view + package_separator; // controls blank lines between packages. + absl::string_view file_separator; // controls blank lines between files. + for (const auto& package : matching_flags) { + if (format == HelpFormat::kHumanReadable) { + out << package_separator; + package_separator = "\n\n"; + } + + file_separator = ""; + for (const auto& flags_in_file : package.second) { + if (format == HelpFormat::kHumanReadable) { + out << file_separator << " Flags from " << flags_in_file.first + << ":\n"; + file_separator = "\n"; + } + + for (const auto* flag : flags_in_file.second) { + flags_internal::FlagHelp(out, *flag, format); + } + } + } + + if (format == HelpFormat::kHumanReadable) { + if (filter_cb && matching_flags.empty()) { + out << " No modules matched: use -helpfull\n"; + } + } else { + // The end of the document. + out << "</AllFlags>\n"; + } +} + +ABSL_CONST_INIT absl::Mutex usage_message_guard(absl::kConstInit); +ABSL_CONST_INIT std::string* program_usage_message + GUARDED_BY(usage_message_guard) = nullptr; + +} // namespace + +// -------------------------------------------------------------------- +// Sets the "usage" message to be used by help reporting routines. + +void SetProgramUsageMessage(absl::string_view new_usage_message) { + absl::MutexLock l(&usage_message_guard); + + if (flags_internal::program_usage_message != nullptr) { + ABSL_INTERNAL_LOG(FATAL, "SetProgramUsageMessage() called twice."); + std::exit(1); + } + + program_usage_message = new std::string(new_usage_message); +} + +// -------------------------------------------------------------------- +// Returns the usage message set by SetProgramUsageMessage(). +// Note: We able to return string_view here only because calling +// SetProgramUsageMessage twice is prohibited. +absl::string_view ProgramUsageMessage() { + absl::MutexLock l(&usage_message_guard); + + return program_usage_message != nullptr + ? absl::string_view(*program_usage_message) + : "Warning: SetProgramUsageMessage() never called"; +} + +// -------------------------------------------------------------------- +// Produces the help message describing specific flag. +void FlagHelp(std::ostream& out, const flags_internal::CommandLineFlag& flag, + HelpFormat format) { + if (format == HelpFormat::kHumanReadable) + flags_internal::FlagHelpHumanReadable(flag, &out); +} + +// -------------------------------------------------------------------- +// Produces the help messages for all flags matching the filter. +// If filter is empty produces help messages for all flags. +void FlagsHelp(std::ostream& out, absl::string_view filter, HelpFormat format) { + flags_internal::FlagKindFilter filter_cb = [&](absl::string_view filename) { + return filter.empty() || filename.find(filter) != absl::string_view::npos; + }; + flags_internal::FlagsHelpImpl(out, filter_cb, format); +} + +// -------------------------------------------------------------------- +// Checks all the 'usage' command line flags to see if any have been set. +// If so, handles them appropriately. +int HandleUsageFlags(std::ostream& out) { + if (absl::GetFlag(FLAGS_helpshort)) { + flags_internal::FlagsHelpImpl( + out, flags_internal::GetUsageConfig().contains_helpshort_flags, + HelpFormat::kHumanReadable); + return 1; + } + + if (absl::GetFlag(FLAGS_helpfull)) { + // show all options + flags_internal::FlagsHelp(out); + return 1; + } + + if (!absl::GetFlag(FLAGS_helpon).empty()) { + flags_internal::FlagsHelp( + out, absl::StrCat("/", absl::GetFlag(FLAGS_helpon), ".")); + return 1; + } + + if (!absl::GetFlag(FLAGS_helpmatch).empty()) { + flags_internal::FlagsHelp(out, absl::GetFlag(FLAGS_helpmatch)); + return 1; + } + + if (absl::GetFlag(FLAGS_help)) { + flags_internal::FlagsHelpImpl( + out, flags_internal::GetUsageConfig().contains_help_flags); + + out << "\nTry --helpfull to get a list of all flags.\n"; + + return 1; + } + + if (absl::GetFlag(FLAGS_helppackage)) { + flags_internal::FlagsHelpImpl( + out, flags_internal::GetUsageConfig().contains_helppackage_flags); + + out << "\nTry --helpfull to get a list of all flags.\n"; + + return 1; + } + + if (absl::GetFlag(FLAGS_version)) { + if (flags_internal::GetUsageConfig().version_string) + out << flags_internal::GetUsageConfig().version_string(); + // Unlike help, we may be asking for version in a script, so return 0 + return 0; + } + + if (absl::GetFlag(FLAGS_only_check_args)) { + return 0; + } + + return -1; +} + +} // namespace flags_internal +} // namespace absl diff --git a/absl/flags/internal/usage.h b/absl/flags/internal/usage.h new file mode 100644 index 000000000000..2d0ea7a72a4d --- /dev/null +++ b/absl/flags/internal/usage.h @@ -0,0 +1,91 @@ +// +// Copyright 2019 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#ifndef ABSL_FLAGS_INTERNAL_USAGE_H_ +#define ABSL_FLAGS_INTERNAL_USAGE_H_ + +#include <iosfwd> +#include <string> + +#include "absl/flags/declare.h" +#include "absl/flags/internal/commandlineflag.h" +#include "absl/strings/string_view.h" + +// -------------------------------------------------------------------- +// Usage reporting interfaces + +namespace absl { +namespace flags_internal { + +// Sets the "usage" message to be used by help reporting routines. +// For example: +// absl::SetProgramUsageMessage( +// absl::StrCat("This program does nothing. Sample usage:\n", argv[0], +// " <uselessarg1> <uselessarg2>")); +// Do not include commandline flags in the usage: we do that for you! +// Note: Calling SetProgramUsageMessage twice will trigger a call to std::exit. +void SetProgramUsageMessage(absl::string_view new_usage_message); + +// Returns the usage message set by SetProgramUsageMessage(). +absl::string_view ProgramUsageMessage(); + +// -------------------------------------------------------------------- + +// The format to report the help messages in. +enum class HelpFormat { + kHumanReadable, +}; + +// Outputs the help message describing specific flag. +void FlagHelp(std::ostream& out, const flags_internal::CommandLineFlag& flag, + HelpFormat format = HelpFormat::kHumanReadable); + +// Produces the help messages for all flags matching the filter. A flag matches +// the filter if it is defined in a file with a filename which includes +// filter string as a substring. You can use '/' and '.' to restrict the +// matching to a specific file names. For example: +// FlagsHelp(out, "/path/to/file."); +// restricts help to only flags which resides in files named like: +// .../path/to/file.<ext> +// for any extension 'ext'. If the filter is empty this function produces help +// messages for all flags. +void FlagsHelp(std::ostream& out, absl::string_view filter = {}, + HelpFormat format = HelpFormat::kHumanReadable); + +// -------------------------------------------------------------------- + +// If any of the 'usage' related command line flags (listed on the bottom of +// this file) has been set this routine produces corresponding help message in +// the specified output stream and returns: +// 0 - if "version" or "only_check_flags" flags were set and handled. +// 1 - if some other 'usage' related flag was set and handled. +// -1 - if no usage flags were set on a commmand line. +// Non negative return values are expected to be used as an exit code for a +// binary. +int HandleUsageFlags(std::ostream& out); + +} // namespace flags_internal +} // namespace absl + +ABSL_DECLARE_FLAG(bool, help); +ABSL_DECLARE_FLAG(bool, helpfull); +ABSL_DECLARE_FLAG(bool, helpshort); +ABSL_DECLARE_FLAG(bool, helppackage); +ABSL_DECLARE_FLAG(bool, version); +ABSL_DECLARE_FLAG(bool, only_check_args); +ABSL_DECLARE_FLAG(std::string, helpon); +ABSL_DECLARE_FLAG(std::string, helpmatch); + +#endif // ABSL_FLAGS_INTERNAL_USAGE_H_ diff --git a/absl/flags/internal/usage_test.cc b/absl/flags/internal/usage_test.cc new file mode 100644 index 000000000000..cb40aa42378d --- /dev/null +++ b/absl/flags/internal/usage_test.cc @@ -0,0 +1,367 @@ +// +// Copyright 2019 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#include <sstream> + +#include "gtest/gtest.h" +#include "absl/flags/flag.h" +#include "absl/flags/parse.h" +#include "absl/flags/internal/path_util.h" +#include "absl/flags/internal/program_name.h" +#include "absl/flags/internal/usage.h" +#include "absl/flags/usage_config.h" +#include "absl/memory/memory.h" +#include "absl/strings/match.h" + +ABSL_FLAG(int, usage_reporting_test_flag_01, 101, + "usage_reporting_test_flag_01 help message"); +ABSL_FLAG(bool, usage_reporting_test_flag_02, false, + "usage_reporting_test_flag_02 help message"); +ABSL_FLAG(double, usage_reporting_test_flag_03, 1.03, + "usage_reporting_test_flag_03 help message"); +ABSL_FLAG(int64_t, usage_reporting_test_flag_04, 1000000000000004L, + "usage_reporting_test_flag_04 help message"); + +struct UDT { + UDT() = default; + UDT(const UDT&) = default; +}; +bool AbslParseFlag(absl::string_view, UDT*, std::string*) { return true; } +std::string AbslUnparseFlag(const UDT&) { return "UDT{}"; } + +ABSL_FLAG(UDT, usage_reporting_test_flag_05, {}, + "usage_reporting_test_flag_05 help message"); + +namespace { + +namespace flags = absl::flags_internal; + +static std::string NormalizeFileName(absl::string_view fname) { +#ifdef _WIN32 + std::string normalized(fname); + std::replace(normalized.begin(), normalized.end(), '\\', '/'); + fname = normalized; +#endif + + auto absl_pos = fname.find("/absl/"); + if (absl_pos != absl::string_view::npos) { + fname = fname.substr(absl_pos + 1); + } + return std::string(fname); +} + +class UsageReportingTest : public testing::Test { + protected: + UsageReportingTest() { + // Install default config for the use on this unit test. + // Binary may install a custom config before tests are run. + absl::FlagsUsageConfig default_config; + default_config.normalize_filename = &NormalizeFileName; + absl::SetFlagsUsageConfig(default_config); + } + + private: + flags::FlagSaver flag_saver_; +}; + +// -------------------------------------------------------------------- + +using UsageReportingDeathTest = UsageReportingTest; + +TEST_F(UsageReportingDeathTest, TestSetProgramUsageMessage) { + EXPECT_EQ(flags::ProgramUsageMessage(), "Custom usage message"); + +#ifndef _WIN32 + // TODO(rogeeff): figure out why this does not work on Windows. + EXPECT_DEATH(flags::SetProgramUsageMessage("custom usage message"), + ".*SetProgramUsageMessage\\(\\) called twice.*"); +#endif +} + +// -------------------------------------------------------------------- + +TEST_F(UsageReportingTest, TestFlagHelpHRF_on_flag_01) { + const auto* flag = flags::FindCommandLineFlag("usage_reporting_test_flag_01"); + std::stringstream test_buf; + + flags::FlagHelp(test_buf, *flag, flags::HelpFormat::kHumanReadable); + EXPECT_EQ( + test_buf.str(), + R"( -usage_reporting_test_flag_01 (usage_reporting_test_flag_01 help message); + default: 101; +)"); +} + +TEST_F(UsageReportingTest, TestFlagHelpHRF_on_flag_02) { + const auto* flag = flags::FindCommandLineFlag("usage_reporting_test_flag_02"); + std::stringstream test_buf; + + flags::FlagHelp(test_buf, *flag, flags::HelpFormat::kHumanReadable); + EXPECT_EQ( + test_buf.str(), + R"( -usage_reporting_test_flag_02 (usage_reporting_test_flag_02 help message); + default: false; +)"); +} + +TEST_F(UsageReportingTest, TestFlagHelpHRF_on_flag_03) { + const auto* flag = flags::FindCommandLineFlag("usage_reporting_test_flag_03"); + std::stringstream test_buf; + + flags::FlagHelp(test_buf, *flag, flags::HelpFormat::kHumanReadable); + EXPECT_EQ( + test_buf.str(), + R"( -usage_reporting_test_flag_03 (usage_reporting_test_flag_03 help message); + default: 1.03; +)"); +} + +TEST_F(UsageReportingTest, TestFlagHelpHRF_on_flag_04) { + const auto* flag = flags::FindCommandLineFlag("usage_reporting_test_flag_04"); + std::stringstream test_buf; + + flags::FlagHelp(test_buf, *flag, flags::HelpFormat::kHumanReadable); + EXPECT_EQ( + test_buf.str(), + R"( -usage_reporting_test_flag_04 (usage_reporting_test_flag_04 help message); + default: 1000000000000004; +)"); +} + +TEST_F(UsageReportingTest, TestFlagHelpHRF_on_flag_05) { + const auto* flag = flags::FindCommandLineFlag("usage_reporting_test_flag_05"); + std::stringstream test_buf; + + flags::FlagHelp(test_buf, *flag, flags::HelpFormat::kHumanReadable); + EXPECT_EQ( + test_buf.str(), + R"( -usage_reporting_test_flag_05 (usage_reporting_test_flag_05 help message); + default: UDT{}; +)"); +} + +// -------------------------------------------------------------------- + +TEST_F(UsageReportingTest, TestFlagsHelpHRF) { + std::string usage_test_flags_out = + R"(usage_test: Custom usage message + + Flags from absl/flags/internal/usage_test.cc: + -usage_reporting_test_flag_01 (usage_reporting_test_flag_01 help message); + default: 101; + -usage_reporting_test_flag_02 (usage_reporting_test_flag_02 help message); + default: false; + -usage_reporting_test_flag_03 (usage_reporting_test_flag_03 help message); + default: 1.03; + -usage_reporting_test_flag_04 (usage_reporting_test_flag_04 help message); + default: 1000000000000004; + -usage_reporting_test_flag_05 (usage_reporting_test_flag_05 help message); + default: UDT{}; +)"; + + std::stringstream test_buf_01; + flags::FlagsHelp(test_buf_01, "usage_test.cc", + flags::HelpFormat::kHumanReadable); + EXPECT_EQ(test_buf_01.str(), usage_test_flags_out); + + std::stringstream test_buf_02; + flags::FlagsHelp(test_buf_02, "flags/internal/usage_test.cc", + flags::HelpFormat::kHumanReadable); + EXPECT_EQ(test_buf_02.str(), usage_test_flags_out); + + std::stringstream test_buf_03; + flags::FlagsHelp(test_buf_03, "usage_test", + flags::HelpFormat::kHumanReadable); + EXPECT_EQ(test_buf_03.str(), usage_test_flags_out); + + std::stringstream test_buf_04; + flags::FlagsHelp(test_buf_04, "flags/invalid_file_name.cc", + flags::HelpFormat::kHumanReadable); + EXPECT_EQ(test_buf_04.str(), + R"(usage_test: Custom usage message + + No modules matched: use -helpfull +)"); + + std::stringstream test_buf_05; + flags::FlagsHelp(test_buf_05, "", flags::HelpFormat::kHumanReadable); + std::string test_out = test_buf_05.str(); + absl::string_view test_out_str(test_out); + EXPECT_TRUE( + absl::StartsWith(test_out_str, "usage_test: Custom usage message")); + EXPECT_TRUE(absl::StrContains( + test_out_str, "Flags from absl/flags/internal/usage_test.cc:")); + EXPECT_TRUE(absl::StrContains(test_out_str, + "Flags from absl/flags/internal/usage.cc:")); + EXPECT_TRUE( + absl::StrContains(test_out_str, "-usage_reporting_test_flag_01 ")); + EXPECT_TRUE(absl::StrContains(test_out_str, "-help (show help")) + << test_out_str; +} + +// -------------------------------------------------------------------- + +TEST_F(UsageReportingTest, TestNoUsageFlags) { + std::stringstream test_buf; + EXPECT_EQ(flags::HandleUsageFlags(test_buf), -1); +} + +// -------------------------------------------------------------------- + +TEST_F(UsageReportingTest, TestUsageFlag_helpshort) { + absl::SetFlag(&FLAGS_helpshort, true); + + std::stringstream test_buf; + EXPECT_EQ(flags::HandleUsageFlags(test_buf), 1); + EXPECT_EQ(test_buf.str(), + R"(usage_test: Custom usage message + + Flags from absl/flags/internal/usage_test.cc: + -usage_reporting_test_flag_01 (usage_reporting_test_flag_01 help message); + default: 101; + -usage_reporting_test_flag_02 (usage_reporting_test_flag_02 help message); + default: false; + -usage_reporting_test_flag_03 (usage_reporting_test_flag_03 help message); + default: 1.03; + -usage_reporting_test_flag_04 (usage_reporting_test_flag_04 help message); + default: 1000000000000004; + -usage_reporting_test_flag_05 (usage_reporting_test_flag_05 help message); + default: UDT{}; +)"); +} + +// -------------------------------------------------------------------- + +TEST_F(UsageReportingTest, TestUsageFlag_help) { + absl::SetFlag(&FLAGS_help, true); + + std::stringstream test_buf; + EXPECT_EQ(flags::HandleUsageFlags(test_buf), 1); + EXPECT_EQ(test_buf.str(), + R"(usage_test: Custom usage message + + Flags from absl/flags/internal/usage_test.cc: + -usage_reporting_test_flag_01 (usage_reporting_test_flag_01 help message); + default: 101; + -usage_reporting_test_flag_02 (usage_reporting_test_flag_02 help message); + default: false; + -usage_reporting_test_flag_03 (usage_reporting_test_flag_03 help message); + default: 1.03; + -usage_reporting_test_flag_04 (usage_reporting_test_flag_04 help message); + default: 1000000000000004; + -usage_reporting_test_flag_05 (usage_reporting_test_flag_05 help message); + default: UDT{}; + +Try --helpfull to get a list of all flags. +)"); +} + +// -------------------------------------------------------------------- + +TEST_F(UsageReportingTest, TestUsageFlag_helppackage) { + absl::SetFlag(&FLAGS_helppackage, true); + + std::stringstream test_buf; + EXPECT_EQ(flags::HandleUsageFlags(test_buf), 1); + EXPECT_EQ(test_buf.str(), + R"(usage_test: Custom usage message + + Flags from absl/flags/internal/usage_test.cc: + -usage_reporting_test_flag_01 (usage_reporting_test_flag_01 help message); + default: 101; + -usage_reporting_test_flag_02 (usage_reporting_test_flag_02 help message); + default: false; + -usage_reporting_test_flag_03 (usage_reporting_test_flag_03 help message); + default: 1.03; + -usage_reporting_test_flag_04 (usage_reporting_test_flag_04 help message); + default: 1000000000000004; + -usage_reporting_test_flag_05 (usage_reporting_test_flag_05 help message); + default: UDT{}; + +Try --helpfull to get a list of all flags. +)"); +} + +// -------------------------------------------------------------------- + +TEST_F(UsageReportingTest, TestUsageFlag_version) { + absl::SetFlag(&FLAGS_version, true); + + std::stringstream test_buf; + EXPECT_EQ(flags::HandleUsageFlags(test_buf), 0); +#ifndef NDEBUG + EXPECT_EQ(test_buf.str(), + "usage_test\nDebug build (NDEBUG not #defined)\n"); +#else + EXPECT_EQ(test_buf.str(), "usage_test\n"); +#endif +} + +// -------------------------------------------------------------------- + +TEST_F(UsageReportingTest, TestUsageFlag_only_check_args) { + absl::SetFlag(&FLAGS_only_check_args, true); + + std::stringstream test_buf; + EXPECT_EQ(flags::HandleUsageFlags(test_buf), 0); + EXPECT_EQ(test_buf.str(), ""); +} + +// -------------------------------------------------------------------- + +TEST_F(UsageReportingTest, TestUsageFlag_helpon) { + absl::SetFlag(&FLAGS_helpon, "bla-bla"); + + std::stringstream test_buf_01; + EXPECT_EQ(flags::HandleUsageFlags(test_buf_01), 1); + EXPECT_EQ(test_buf_01.str(), + R"(usage_test: Custom usage message + + No modules matched: use -helpfull +)"); + + absl::SetFlag(&FLAGS_helpon, "usage_test"); + + std::stringstream test_buf_02; + EXPECT_EQ(flags::HandleUsageFlags(test_buf_02), 1); + EXPECT_EQ(test_buf_02.str(), + R"(usage_test: Custom usage message + + Flags from absl/flags/internal/usage_test.cc: + -usage_reporting_test_flag_01 (usage_reporting_test_flag_01 help message); + default: 101; + -usage_reporting_test_flag_02 (usage_reporting_test_flag_02 help message); + default: false; + -usage_reporting_test_flag_03 (usage_reporting_test_flag_03 help message); + default: 1.03; + -usage_reporting_test_flag_04 (usage_reporting_test_flag_04 help message); + default: 1000000000000004; + -usage_reporting_test_flag_05 (usage_reporting_test_flag_05 help message); + default: UDT{}; +)"); +} + +// -------------------------------------------------------------------- + +} // namespace + +int main(int argc, char* argv[]) { + absl::GetFlag(FLAGS_undefok); // Force linking of parse.cc + flags::SetProgramInvocationName("usage_test"); + flags::SetProgramUsageMessage("Custom usage message"); + ::testing::InitGoogleTest(&argc, argv); + + return RUN_ALL_TESTS(); +} |