| // |
| // 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 { |
| |
| // 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 |
| |
| absl::Mutex* InitFlag(CommandLineFlag* flag) { |
| ABSL_CONST_INIT static absl::Mutex init_lock(absl::kConstInit); |
| absl::Mutex* mu; |
| |
| { |
| absl::MutexLock lock(&init_lock); |
| |
| if (flag->locks_ == nullptr) { // Must initialize Mutexes for this flag. |
| flag->locks_ = new flags_internal::CommandLineFlagLocks; |
| } |
| |
| mu = &flag->locks_->primary_mu; |
| } |
| |
| { |
| absl::MutexLock lock(mu); |
| |
| 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_); |
| UpdateCopy(flag); |
| flag->inited_.store(true, std::memory_order_release); |
| flag->InvokeCallback(); |
| } |
| } |
| |
| flag->inited_.store(true, std::memory_order_release); |
| return mu; |
| } |
| |
| // Ensure that the lazily initialized fields of *flag have been initialized, |
| // and return &flag->locks_->primary_mu. |
| absl::Mutex* CommandLineFlag::InitFlagIfNecessary() const |
| ABSL_LOCK_RETURNED(locks_->primary_mu) { |
| if (!inited_.load(std::memory_order_acquire)) { |
| return InitFlag(const_cast<CommandLineFlag*>(this)); |
| } |
| |
| // All fields initialized; locks_ is therefore safe to read. |
| return &locks_->primary_mu; |
| } |
| |
| bool CommandLineFlag::IsModified() const { |
| absl::MutexLock l(InitFlagIfNecessary()); |
| return modified_; |
| } |
| |
| void CommandLineFlag::SetModified(bool is_modified) { |
| absl::MutexLock l(InitFlagIfNecessary()); |
| modified_ = is_modified; |
| } |
| |
| bool CommandLineFlag::IsSpecifiedOnCommandLine() const { |
| absl::MutexLock l(InitFlagIfNecessary()); |
| return on_command_line_; |
| } |
| |
| 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(filename_); |
| } |
| |
| std::string CommandLineFlag::DefaultValue() const { |
| absl::MutexLock l(InitFlagIfNecessary()); |
| |
| return Unparse(marshalling_op_, def_); |
| } |
| |
| std::string CommandLineFlag::CurrentValue() const { |
| absl::MutexLock l(InitFlagIfNecessary()); |
| |
| return Unparse(marshalling_op_, cur_); |
| } |
| |
| // 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' |
| bool TryParseLocked(CommandLineFlag* flag, void* dst, absl::string_view value, |
| std::string* err) |
| ABSL_EXCLUSIVE_LOCKS_REQUIRED(flag->locks_->primary_mu) { |
| 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 (!flag->InvokeValidator(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; |
| |
| absl::MutexLock l(InitFlagIfNecessary()); |
| |
| // Direct-access flags can be modified without going through the |
| // flag API. Detect such changes and update the flag->modified_ bit. |
| if (!IsAbseilFlag()) { |
| if (!modified_ && ChangedDirectly(this, cur_, def_)) { |
| modified_ = true; |
| } |
| } |
| |
| switch (set_mode) { |
| case SET_FLAGS_VALUE: { |
| // set or modify the flag's value |
| if (!TryParseLocked(this, cur_, value, err)) return false; |
| modified_ = true; |
| UpdateCopy(this); |
| InvokeCallback(); |
| |
| if (source == kCommandLine) { |
| 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 (!modified_) { |
| if (!TryParseLocked(this, cur_, value, err)) return false; |
| modified_ = true; |
| UpdateCopy(this); |
| InvokeCallback(); |
| } 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(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, def_, value, err)) return false; |
| |
| if (!modified_) { |
| // Need to set both defvalue *and* current, in this case |
| Copy(op_, def_, cur_); |
| UpdateCopy(this); |
| InvokeCallback(); |
| } |
| break; |
| } |
| default: { |
| // unknown set_mode |
| assert(false); |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| |
| void CommandLineFlag::CheckDefaultValueParsingRoundtrip() const { |
| std::string v = DefaultValue(); |
| |
| absl::MutexLock lock(InitFlagIfNecessary()); |
| |
| void* dst = Clone(op_, def_); |
| std::string error; |
| if (!flags_internal::Parse(marshalling_op_, v, dst, &error)) { |
| ABSL_INTERNAL_LOG( |
| FATAL, |
| absl::StrCat("Flag ", Name(), " (from ", Filename(), |
| "): std::string form of default value '", v, |
| "' could not be parsed; error=", error)); |
| } |
| |
| // We do not compare dst to def since parsing/unparsing may make |
| // small changes, e.g., precision loss for floating point types. |
| Delete(op_, dst); |
| } |
| |
| bool CommandLineFlag::ValidateDefaultValue() const { |
| absl::MutexLock lock(InitFlagIfNecessary()); |
| return InvokeValidator(def_); |
| } |
| |
| bool CommandLineFlag::ValidateInputValue(absl::string_view value) const { |
| absl::MutexLock l(InitFlagIfNecessary()); // protect default value access |
| |
| void* obj = Clone(op_, def_); |
| std::string ignored_error; |
| const bool result = |
| flags_internal::Parse(marshalling_op_, value, obj, &ignored_error) && |
| InvokeValidator(obj); |
| Delete(op_, obj); |
| return result; |
| } |
| |
| void CommandLineFlag::Read(void* dst, |
| const flags_internal::FlagOpFn dst_op) const { |
| absl::ReaderMutexLock l(InitFlagIfNecessary()); |
| |
| // `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::MutexLock l(InitFlagIfNecessary()); |
| |
| // `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) || |
| !InvokeValidator(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); |
| InvokeCallback(); |
| } |
| |
| std::string HelpText::GetHelpText() const { |
| if (help_function_) return help_function_(); |
| if (help_message_) return help_message_; |
| |
| return {}; |
| } |
| |
| // 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) { |
| #define STORE_ATOMIC(T) \ |
| else if (flag->IsOfType<T>()) { \ |
| flag->StoreAtomic(); \ |
| } |
| |
| if (false) { |
| } |
| ABSL_FLAGS_INTERNAL_FOR_EACH_LOCK_FREE(STORE_ATOMIC) |
| #undef STORE_ATOMIC |
| } |
| |
| // 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; |
| } |
| |
| } // namespace flags_internal |
| } // namespace absl |