diff options
Diffstat (limited to 'src/google/protobuf/metadata.h')
-rw-r--r-- | src/google/protobuf/metadata.h | 115 |
1 files changed, 15 insertions, 100 deletions
diff --git a/src/google/protobuf/metadata.h b/src/google/protobuf/metadata.h index 219645d3..0a6507c0 100644 --- a/src/google/protobuf/metadata.h +++ b/src/google/protobuf/metadata.h @@ -38,124 +38,39 @@ #ifndef GOOGLE_PROTOBUF_METADATA_H__ #define GOOGLE_PROTOBUF_METADATA_H__ -#include <google/protobuf/stubs/common.h> -#include <google/protobuf/arena.h> +#include <google/protobuf/metadata_lite.h> #include <google/protobuf/unknown_field_set.h> namespace google { namespace protobuf { namespace internal { -// This is the representation for messages that support arena allocation. It -// uses a tagged pointer to either store the Arena pointer, if there are no -// unknown fields, or a pointer to a block of memory with both the Arena pointer -// and the UnknownFieldSet, if there are unknown fields. This optimization -// allows for "zero-overhead" storage of the Arena pointer, relative to the -// above baseline implementation. -// -// The tagged pointer uses the LSB to disambiguate cases, and uses bit 0 == 0 to -// indicate an arena pointer and bit 0 == 1 to indicate a UFS+Arena-container -// pointer. -class InternalMetadataWithArena { +class InternalMetadataWithArena + : public InternalMetadataWithArenaBase<UnknownFieldSet, + InternalMetadataWithArena> { public: - InternalMetadataWithArena() : ptr_(NULL) {} + InternalMetadataWithArena() {} explicit InternalMetadataWithArena(Arena* arena) - : ptr_ (arena) {} - - ~InternalMetadataWithArena() { - if (have_unknown_fields() && arena() == NULL) { - delete PtrValue<Container>(); - } - ptr_ = NULL; - } - - GOOGLE_ATTRIBUTE_ALWAYS_INLINE const UnknownFieldSet& unknown_fields() const { - if (GOOGLE_PREDICT_FALSE(have_unknown_fields())) { - return PtrValue<Container>()->unknown_fields_; - } else { - return *UnknownFieldSet::default_instance(); - } - } + : InternalMetadataWithArenaBase<UnknownFieldSet, + InternalMetadataWithArena>(arena) {} - GOOGLE_ATTRIBUTE_ALWAYS_INLINE UnknownFieldSet* mutable_unknown_fields() { - if (GOOGLE_PREDICT_TRUE(have_unknown_fields())) { - return &PtrValue<Container>()->unknown_fields_; - } else { - return mutable_unknown_fields_slow(); - } + void DoSwap(UnknownFieldSet* other) { + mutable_unknown_fields()->Swap(other); } - GOOGLE_ATTRIBUTE_ALWAYS_INLINE Arena* arena() const { - if (GOOGLE_PREDICT_FALSE(have_unknown_fields())) { - return PtrValue<Container>()->arena_; - } else { - return PtrValue<Arena>(); - } + void DoMergeFrom(const UnknownFieldSet& other) { + mutable_unknown_fields()->MergeFrom(other); } - GOOGLE_ATTRIBUTE_ALWAYS_INLINE bool have_unknown_fields() const { - return PtrTag() == kTagContainer; + void DoClear() { + mutable_unknown_fields()->Clear(); } - GOOGLE_ATTRIBUTE_ALWAYS_INLINE void Swap(InternalMetadataWithArena* other) { - // Semantics here are that we swap only the unknown fields, not the arena - // pointer. We cannot simply swap ptr_ with other->ptr_ because we need to - // maintain our own arena ptr. Also, our ptr_ and other's ptr_ may be in - // different states (direct arena pointer vs. container with UFS) so we - // cannot simply swap ptr_ and then restore the arena pointers. We reuse - // UFS's swap implementation instead. - if (have_unknown_fields() || other->have_unknown_fields()) { - mutable_unknown_fields()->Swap(other->mutable_unknown_fields()); - } - } - - GOOGLE_ATTRIBUTE_ALWAYS_INLINE void* raw_arena_ptr() const { - return ptr_; - } - - private: - void* ptr_; - - // Tagged pointer implementation. - enum { - // ptr_ is an Arena*. - kTagArena = 0, - // ptr_ is a Container*. - kTagContainer = 1, - }; - static const intptr_t kPtrTagMask = 1; - static const intptr_t kPtrValueMask = ~kPtrTagMask; - - // Accessors for pointer tag and pointer value. - GOOGLE_ATTRIBUTE_ALWAYS_INLINE int PtrTag() const { - return reinterpret_cast<intptr_t>(ptr_) & kPtrTagMask; - } - - template<typename T> T* PtrValue() const { - return reinterpret_cast<T*>( - reinterpret_cast<intptr_t>(ptr_) & kPtrValueMask); - } - - // If ptr_'s tag is kTagContainer, it points to an instance of this struct. - struct Container { - UnknownFieldSet unknown_fields_; - Arena* arena_; - }; - - GOOGLE_ATTRIBUTE_NOINLINE UnknownFieldSet* mutable_unknown_fields_slow() { - Arena* my_arena = arena(); - Container* container = Arena::Create<Container>(my_arena); - ptr_ = reinterpret_cast<void*>( - reinterpret_cast<intptr_t>(container) | kTagContainer); - container->arena_ = my_arena; - return &(container->unknown_fields_); + static const UnknownFieldSet& default_instance() { + return *UnknownFieldSet::default_instance(); } }; -// Temporary compatibility typedef. Remove once this is released in components -// and upb CL is submitted. -typedef InternalMetadataWithArena InternalMetadata; - } // namespace internal } // namespace protobuf |