diff options
Diffstat (limited to 'absl/flags/reflection.cc')
-rw-r--r-- | absl/flags/reflection.cc | 93 |
1 files changed, 63 insertions, 30 deletions
diff --git a/absl/flags/reflection.cc b/absl/flags/reflection.cc index d7060221..0c761101 100644 --- a/absl/flags/reflection.cc +++ b/absl/flags/reflection.cc @@ -17,6 +17,7 @@ #include <assert.h> +#include <atomic> #include <map> #include <string> @@ -49,28 +50,30 @@ class FlagRegistry { ~FlagRegistry() = default; // Store a flag in this registry. Takes ownership of *flag. - void RegisterFlag(CommandLineFlag& flag); + void RegisterFlag(CommandLineFlag& flag, const char* filename); void Lock() ABSL_EXCLUSIVE_LOCK_FUNCTION(lock_) { lock_.Lock(); } void Unlock() ABSL_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); + CommandLineFlag* FindFlag(absl::string_view name); static FlagRegistry& GlobalRegistry(); // returns a singleton registry private: friend class flags_internal::FlagSaverImpl; // reads all the flags in order // to copy them - friend void ForEachFlagUnlocked( - std::function<void(CommandLineFlag&)> visitor); + friend void ForEachFlag(std::function<void(CommandLineFlag&)> visitor); + friend void FinalizeRegistry(); - // The map from name to flag, for FindFlagLocked(). + // The map from name to flag, for FindFlag(). using FlagMap = std::map<absl::string_view, CommandLineFlag*>; using FlagIterator = FlagMap::iterator; using FlagConstIterator = FlagMap::const_iterator; FlagMap flags_; + std::vector<CommandLineFlag*> flat_flags_; + std::atomic<bool> finalized_flags_{false}; absl::Mutex lock_; @@ -79,15 +82,6 @@ class FlagRegistry { FlagRegistry& operator=(const FlagRegistry&); }; -CommandLineFlag* FlagRegistry::FindFlagLocked(absl::string_view name) { - FlagConstIterator i = flags_.find(name); - if (i == flags_.end()) { - return nullptr; - } - - return i->second; -} - namespace { class FlagRegistryLock { @@ -101,8 +95,37 @@ class FlagRegistryLock { } // namespace -void FlagRegistry::RegisterFlag(CommandLineFlag& flag) { +CommandLineFlag* FlagRegistry::FindFlag(absl::string_view name) { + if (finalized_flags_.load(std::memory_order_acquire)) { + // We could save some gcus here if we make `Name()` be non-virtual. + // We could move the `const char*` name to the base class. + auto it = std::partition_point( + flat_flags_.begin(), flat_flags_.end(), + [=](CommandLineFlag* f) { return f->Name() < name; }); + if (it != flat_flags_.end() && (*it)->Name() == name) return *it; + } + + FlagRegistryLock frl(*this); + auto it = flags_.find(name); + return it != flags_.end() ? it->second : nullptr; +} + +void FlagRegistry::RegisterFlag(CommandLineFlag& flag, const char* filename) { + if (filename != nullptr && + flag.Filename() != GetUsageConfig().normalize_filename(filename)) { + flags_internal::ReportUsageError( + absl::StrCat( + "Inconsistency between flag object and registration for flag '", + flag.Name(), + "', likely due to duplicate flags or an ODR violation. Relevant " + "files: ", + flag.Filename(), " and ", filename), + true); + std::exit(1); + } + 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 @@ -152,27 +175,39 @@ FlagRegistry& FlagRegistry::GlobalRegistry() { // -------------------------------------------------------------------- -void ForEachFlagUnlocked(std::function<void(CommandLineFlag&)> visitor) { +void ForEachFlag(std::function<void(CommandLineFlag&)> visitor) { FlagRegistry& registry = FlagRegistry::GlobalRegistry(); - for (FlagRegistry::FlagConstIterator i = registry.flags_.begin(); - i != registry.flags_.end(); ++i) { - visitor(*i->second); + + if (registry.finalized_flags_.load(std::memory_order_acquire)) { + for (const auto& i : registry.flat_flags_) visitor(*i); } -} -void ForEachFlag(std::function<void(CommandLineFlag&)> visitor) { - FlagRegistry& registry = FlagRegistry::GlobalRegistry(); FlagRegistryLock frl(registry); - ForEachFlagUnlocked(visitor); + for (const auto& i : registry.flags_) visitor(*i.second); } // -------------------------------------------------------------------- -bool RegisterCommandLineFlag(CommandLineFlag& flag) { - FlagRegistry::GlobalRegistry().RegisterFlag(flag); +bool RegisterCommandLineFlag(CommandLineFlag& flag, const char* filename) { + FlagRegistry::GlobalRegistry().RegisterFlag(flag, filename); return true; } +void FinalizeRegistry() { + auto& registry = FlagRegistry::GlobalRegistry(); + FlagRegistryLock frl(registry); + if (registry.finalized_flags_.load(std::memory_order_relaxed)) { + // Was already finalized. Ignore the second time. + return; + } + registry.flat_flags_.reserve(registry.flags_.size()); + for (const auto& f : registry.flags_) { + registry.flat_flags_.push_back(f.second); + } + registry.flags_.clear(); + registry.finalized_flags_.store(true, std::memory_order_release); +} + // -------------------------------------------------------------------- namespace { @@ -244,7 +279,7 @@ void Retire(const char* name, FlagFastTypeId type_id, char* buf) { static_assert(alignof(RetiredFlagObj) == kRetiredFlagObjAlignment, ""); auto* flag = ::new (static_cast<void*>(buf)) flags_internal::RetiredFlagObj(name, type_id); - FlagRegistry::GlobalRegistry().RegisterFlag(*flag); + FlagRegistry::GlobalRegistry().RegisterFlag(*flag, nullptr); } // -------------------------------------------------------------------- @@ -298,9 +333,7 @@ CommandLineFlag* FindCommandLineFlag(absl::string_view name) { if (name.empty()) return nullptr; flags_internal::FlagRegistry& registry = flags_internal::FlagRegistry::GlobalRegistry(); - flags_internal::FlagRegistryLock frl(registry); - - return registry.FindFlagLocked(name); + return registry.FindFlag(name); } // -------------------------------------------------------------------- @@ -308,7 +341,7 @@ CommandLineFlag* FindCommandLineFlag(absl::string_view name) { absl::flat_hash_map<absl::string_view, absl::CommandLineFlag*> GetAllFlags() { absl::flat_hash_map<absl::string_view, absl::CommandLineFlag*> res; flags_internal::ForEachFlag([&](CommandLineFlag& flag) { - res.insert({flag.Name(), &flag}); + if (!flag.IsRetired()) res.insert({flag.Name(), &flag}); }); return res; } |