Squashed 'third_party/abseil/' content from commit ddf8e52a2
Change-Id: I330cdc687395c6605ad027b855e313ff4a2059e9
git-subtree-dir: third_party/abseil
git-subtree-split: ddf8e52a2918dd0ccec75d3e2426125fa3926724
diff --git a/absl/flags/internal/commandlineflag.cc b/absl/flags/internal/commandlineflag.cc
new file mode 100644
index 0000000..53e2b84
--- /dev/null
+++ b/absl/flags/internal/commandlineflag.cc
@@ -0,0 +1,394 @@
+//
+// 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