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Diffstat (limited to 'absl/flags/internal/type_erased.h')
-rw-r--r-- | absl/flags/internal/type_erased.h | 97 |
1 files changed, 97 insertions, 0 deletions
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_ |