diff options
Diffstat (limited to 'absl/flags/internal')
| -rw-r--r-- | absl/flags/internal/commandlineflag.cc | 93 | ||||
| -rw-r--r-- | absl/flags/internal/commandlineflag.h | 64 | ||||
| -rw-r--r-- | absl/flags/internal/flag.cc | 51 | ||||
| -rw-r--r-- | absl/flags/internal/flag.h | 49 | ||||
| -rw-r--r-- | absl/flags/internal/registry.cc | 62 | ||||
| -rw-r--r-- | absl/flags/internal/registry.h | 21 | ||||
| -rw-r--r-- | absl/flags/internal/usage_test.cc | 2 |
7 files changed, 165 insertions, 177 deletions
diff --git a/absl/flags/internal/commandlineflag.cc b/absl/flags/internal/commandlineflag.cc index 98a46695304b..2063cda64d5d 100644 --- a/absl/flags/internal/commandlineflag.cc +++ b/absl/flags/internal/commandlineflag.cc @@ -68,7 +68,7 @@ absl::Mutex* InitFlag(CommandLineFlag* flag) { { absl::MutexLock lock(mu); - if (!flag->retired && flag->def == nullptr) { + if (!flag->IsRetired() && flag->def == nullptr) { // Need to initialize def and cur fields. flag->def = (*flag->make_init_value)(); flag->cur = Clone(flag->op, flag->def); @@ -94,16 +94,6 @@ absl::Mutex* CommandLineFlag::InitFlagIfNecessary() const return &this->locks->primary_mu; } -void CommandLineFlag::Destroy() const { - // Values are heap allocated for retired and Abseil Flags. - if (IsRetired() || IsAbseilFlag()) { - if (this->cur) Delete(this->op, this->cur); - if (this->def) Delete(this->op, this->def); - } - - delete this->locks; -} - bool CommandLineFlag::IsModified() const { absl::MutexLock l(InitFlagIfNecessary()); return modified; @@ -159,87 +149,6 @@ std::string CommandLineFlag::CurrentValue() const { return Unparse(this->marshalling_op, this->cur); } -bool CommandLineFlag::HasValidatorFn() const { - absl::MutexLock l(InitFlagIfNecessary()); - - return this->validator != nullptr; -} - -bool CommandLineFlag::SetValidatorFn(FlagValidator fn) { - absl::MutexLock l(InitFlagIfNecessary()); - - // ok to register the same function over and over again - if (fn == this->validator) return true; - - // Can't set validator to a different function, unless reset first. - if (fn != nullptr && this->validator != nullptr) { - ABSL_INTERNAL_LOG( - WARNING, absl::StrCat("Ignoring SetValidatorFn() for flag '", Name(), - "': validate-fn already registered")); - - return false; - } - - this->validator = fn; - return true; -} - -bool CommandLineFlag::InvokeValidator(const void* value) const - EXCLUSIVE_LOCKS_REQUIRED(this->locks->primary_mu) { - if (!this->validator) { - return true; - } - - (void)value; - - ABSL_INTERNAL_LOG( - FATAL, - absl::StrCat("Flag '", Name(), - "' of encapsulated type should not have a validator")); - - return false; -} - -void CommandLineFlag::SetCallback( - const flags_internal::FlagCallback mutation_callback) { - absl::MutexLock l(InitFlagIfNecessary()); - - callback = mutation_callback; - - InvokeCallback(); -} - -// 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 CommandLineFlag::InvokeCallback() - EXCLUSIVE_LOCKS_REQUIRED(this->locks->primary_mu) { - if (!this->callback) return; - - // The callback lock is guaranteed initialized, because *locks->primary_mu - // exists. - absl::Mutex* callback_mu = &this->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. - this->locks->primary_mu.Unlock(); - - { - absl::MutexLock lock(callback_mu); - this->callback(); - } - - this->locks->primary_mu.Lock(); -} - // 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 diff --git a/absl/flags/internal/commandlineflag.h b/absl/flags/internal/commandlineflag.h index d82443a7760e..235125762b27 100644 --- a/absl/flags/internal/commandlineflag.h +++ b/absl/flags/internal/commandlineflag.h @@ -71,13 +71,6 @@ using InitialValGenFunc = void* (*)(); struct CommandLineFlagInfo; -// 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 (*)(); - -using FlagValidator = bool (*)(); - extern const char kStrippedFlagHelp[]; // The per-type function @@ -201,53 +194,55 @@ struct 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) + const flags_internal::InitialValGenFunc initial_value_gen, 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) {} - // Revert the init routine. - void Destroy() const; + // Virtual destructor + virtual void Destroy() const = 0; // Not copyable/assignable. CommandLineFlag(const CommandLineFlag&) = delete; CommandLineFlag& operator=(const CommandLineFlag&) = delete; + // Access methods. + + // Returns true iff this object corresponds to retired flag + virtual bool IsRetired() const { return false; } + // Returns true iff this is a handle to an Abseil Flag. + virtual bool IsAbseilFlag() const { return true; } + absl::string_view Name() const { return name; } std::string Help() const { return help.GetHelpText(); } - bool IsRetired() const { return this->retired; } bool IsModified() const; void SetModified(bool is_modified); bool IsSpecifiedOnCommandLine() const; - // 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; - bool HasValidatorFn() const; - bool SetValidatorFn(FlagValidator fn); - bool InvokeValidator(const void* value) const; + // Interfaces to operate on validators. + virtual bool HasValidatorFn() const { return false; } + virtual bool InvokeValidator(const void* /*value*/) const { return true; } + // Invoke the flag validators for old flags. + // TODO(rogeeff): implement proper validators for Abseil Flags + bool ValidateDefaultValue() const; + bool ValidateInputValue(absl::string_view value) const; // Return true iff flag has type T. template <typename T> @@ -268,8 +263,8 @@ struct CommandLineFlag { return res; } - void SetCallback(const flags_internal::FlagCallback mutation_callback); - void InvokeCallback(); + // Interfaces to overate on callbacks. + virtual void InvokeCallback() {} // 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` @@ -286,29 +281,23 @@ struct CommandLineFlag { void StoreAtomic(size_t size); void CheckDefaultValueParsingRoundtrip() const; - // Invoke the flag validators for old flags. - // TODO(rogeeff): implement proper validators for Abseil Flags - bool ValidateDefaultValue() const; - bool ValidateInputValue(absl::string_view value) const; // Constant configuration for a particular flag. - private: + protected: + ~CommandLineFlag() = default; + const char* const name; const HelpText help; const char* const filename; - protected: 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. - FlagValidator 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 @@ -326,7 +315,7 @@ struct CommandLineFlag { // Ensure that the lazily initialized fields of *flag have been initialized, // and return the lock which should be locked when flag's state is mutated. - absl::Mutex* InitFlagIfNecessary() const; + absl::Mutex* InitFlagIfNecessary() const LOCK_RETURNED(locks->primary_mu); // copy construct new value of flag's type in a memory referenced by dst // based on current flag's value @@ -342,6 +331,11 @@ struct CommandLineFlag { friend bool TryParseLocked(CommandLineFlag* flag, void* dst, absl::string_view value, std::string* err); friend absl::Mutex* InitFlag(CommandLineFlag* flag); + + // This is a short term, until we completely rework persistent state + // storage API. + virtual void* GetValidator() const { return nullptr; } + virtual void SetValidator(void*) {} }; // Update any copy of the flag value that is stored in an atomic word. diff --git a/absl/flags/internal/flag.cc b/absl/flags/internal/flag.cc new file mode 100644 index 000000000000..34629b304aa1 --- /dev/null +++ b/absl/flags/internal/flag.cc @@ -0,0 +1,51 @@ +// +// 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/flag.h" + +#include "absl/synchronization/mutex.h" + +namespace absl { +namespace flags_internal { + +// 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(absl::Mutex* primary_mu, absl::Mutex* callback_mu, + FlagCallback cb) EXCLUSIVE_LOCKS_REQUIRED(primary_mu) { + if (!cb) return; + + // When executing the callback we need the primary flag's mutex to be + // unlocked so that callback can retrieve the flag's value. + primary_mu->Unlock(); + + { + absl::MutexLock lock(callback_mu); + cb(); + } + + primary_mu->Lock(); +} + +} // namespace flags_internal +} // namespace absl diff --git a/absl/flags/internal/flag.h b/absl/flags/internal/flag.h index bc50de5486bc..fad36877f74e 100644 --- a/absl/flags/internal/flag.h +++ b/absl/flags/internal/flag.h @@ -22,20 +22,30 @@ namespace absl { namespace flags_internal { +// 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 (*)(); + +void InvokeCallback(absl::Mutex* primary_mu, absl::Mutex* callback_mu, + FlagCallback cb) EXCLUSIVE_LOCKS_REQUIRED(primary_mu); + // This is "unspecified" implementation of absl::Flag<T> type. template <typename T> -class Flag : public flags_internal::CommandLineFlag { +class Flag final : public flags_internal::CommandLineFlag { public: - constexpr Flag(const char* name, const flags_internal::HelpGenFunc help_gen, - const char* filename, + constexpr Flag(const char* name_arg, + const flags_internal::HelpGenFunc help_gen, + const char* filename_arg, const flags_internal::FlagMarshallingOpFn marshalling_op_arg, const flags_internal::InitialValGenFunc initial_value_gen) : flags_internal::CommandLineFlag( - name, flags_internal::HelpText::FromFunctionPointer(help_gen), - filename, &flags_internal::FlagOps<T>, marshalling_op_arg, + name_arg, flags_internal::HelpText::FromFunctionPointer(help_gen), + filename_arg, &flags_internal::FlagOps<T>, marshalling_op_arg, initial_value_gen, - /*retired_arg=*/false, /*def_arg=*/nullptr, - /*cur_arg=*/nullptr) {} + /*def_arg=*/nullptr, + /*cur_arg=*/nullptr), + callback_(nullptr) {} T Get() const { // Implementation notes: @@ -76,6 +86,31 @@ class Flag : public flags_internal::CommandLineFlag { } void Set(const T& v) { this->Write(&v, &flags_internal::FlagOps<T>); } + + void SetCallback(const flags_internal::FlagCallback mutation_callback) { + absl::MutexLock l(InitFlagIfNecessary()); + + callback_ = mutation_callback; + + InvokeCallback(); + } + void InvokeCallback() override + EXCLUSIVE_LOCKS_REQUIRED(this->locks->primary_mu) { + flags_internal::InvokeCallback(&this->locks->primary_mu, + &this->locks->callback_mu, callback_); + } + + private: + void Destroy() const override { + // Values are heap allocated Abseil Flags. + if (this->cur) Delete(this->op, this->cur); + if (this->def) Delete(this->op, this->def); + + delete this->locks; + } + + // Flag's data + FlagCallback callback_; // Mutation callback }; // This class facilitates Flag object registration and tail expression-based diff --git a/absl/flags/internal/registry.cc b/absl/flags/internal/registry.cc index 4e5d1106b93c..0d4eec982ba7 100644 --- a/absl/flags/internal/registry.cc +++ b/absl/flags/internal/registry.cc @@ -31,18 +31,6 @@ namespace absl { namespace flags_internal { -namespace { - -void DestroyFlag(CommandLineFlag* flag) NO_THREAD_SAFETY_ANALYSIS { - flag->Destroy(); - - // CommandLineFlag handle object is heap allocated for non Abseil Flags. - if (!flag->IsAbseilFlag()) { - delete flag; - } -} - -} // namespace // -------------------------------------------------------------------- // FlagRegistry @@ -59,7 +47,7 @@ class FlagRegistry { FlagRegistry() = default; ~FlagRegistry() { for (auto& p : flags_) { - DestroyFlag(p.second); + p.second->Destroy(); } } @@ -141,7 +129,7 @@ void FlagRegistry::RegisterFlag(CommandLineFlag* flag) { true); } else if (old_flag->IsRetired()) { // Retired definitions are idempotent. Just keep the old one. - DestroyFlag(flag); + flag->Destroy(); return; } else if (old_flag->Filename() != flag->Filename()) { flags_internal::ReportUsageError( @@ -224,7 +212,7 @@ class FlagSaverImpl { saved.marshalling_op = flag->marshalling_op; { absl::MutexLock l(flag->InitFlagIfNecessary()); - saved.validator = flag->validator; + saved.validator = flag->GetValidator(); saved.modified = flag->modified; saved.on_command_line = flag->on_command_line; saved.current = Clone(saved.op, flag->cur); @@ -250,7 +238,7 @@ class FlagSaverImpl { bool restored = false; { absl::MutexLock l(flag->InitFlagIfNecessary()); - flag->validator = src.validator; + flag->SetValidator(src.validator); flag->modified = src.modified; flag->on_command_line = src.on_command_line; if (flag->counter != src.counter || @@ -290,9 +278,9 @@ class FlagSaverImpl { FlagOpFn op; FlagMarshallingOpFn marshalling_op; int64_t counter; + void* validator; bool modified; bool on_command_line; - bool (*validator)(); const void* current; // nullptr after restore const void* default_value; // nullptr after restore }; @@ -414,14 +402,38 @@ bool RegisterCommandLineFlag(CommandLineFlag* flag) { // -------------------------------------------------------------------- -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); +namespace { + +class RetiredFlagObj final : public flags_internal::CommandLineFlag { + public: + constexpr RetiredFlagObj(const char* name_arg, FlagOpFn ops, + FlagMarshallingOpFn marshalling_ops) + : flags_internal::CommandLineFlag( + name_arg, flags_internal::HelpText::FromStaticCString(nullptr), + /*filename_arg=*/"RETIRED", ops, marshalling_ops, + /*initial_value_gen=*/nullptr, + /*def_arg=*/nullptr, + /*cur_arg=*/nullptr) {} + + private: + bool IsRetired() const override { return true; } + + void Destroy() const override { + // Values are heap allocated for Retired Flags. + if (this->cur) Delete(this->op, this->cur); + if (this->def) Delete(this->op, this->def); + + if (this->locks) delete this->locks; + + delete this; + } +}; + +} // namespace + +bool Retire(const char* name, FlagOpFn ops, + FlagMarshallingOpFn marshalling_ops) { + auto* flag = new flags_internal::RetiredFlagObj(name, ops, marshalling_ops); FlagRegistry::GlobalRegistry()->RegisterFlag(flag); return true; } diff --git a/absl/flags/internal/registry.h b/absl/flags/internal/registry.h index 27566fbf4ab7..884a8db542fa 100644 --- a/absl/flags/internal/registry.h +++ b/absl/flags/internal/registry.h @@ -106,29 +106,16 @@ bool RegisterCommandLineFlag(CommandLineFlag*); // 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); +bool Retire(const char* name, FlagOpFn ops, + FlagMarshallingOpFn marshalling_ops); // 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); + return flags_internal::Retire(flag_name, flags_internal::FlagOps<T>, + flags_internal::FlagMarshallingOps<T>); } // If the flag is retired, returns true and indicates in |*type_is_bool| diff --git a/absl/flags/internal/usage_test.cc b/absl/flags/internal/usage_test.cc index 781e1d2b16ab..8538b2b60884 100644 --- a/absl/flags/internal/usage_test.cc +++ b/absl/flags/internal/usage_test.cc @@ -395,7 +395,7 @@ TEST_F(UsageReportingTest, TestUsageFlag_helpon) { } // namespace int main(int argc, char* argv[]) { - absl::GetFlag(FLAGS_undefok); // Force linking of parse.cc + (void)absl::GetFlag(FLAGS_undefok); // Force linking of parse.cc flags::SetProgramInvocationName("usage_test"); absl::SetProgramUsageMessage(kTestUsageMessage); ::testing::InitGoogleTest(&argc, argv); |