diff options
Diffstat (limited to 'src/google/protobuf/arena.h')
| -rw-r--r-- | src/google/protobuf/arena.h | 346 |
1 files changed, 302 insertions, 44 deletions
diff --git a/src/google/protobuf/arena.h b/src/google/protobuf/arena.h index b48bef92..4adcd677 100644 --- a/src/google/protobuf/arena.h +++ b/src/google/protobuf/arena.h @@ -28,12 +28,12 @@ // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. -// This header is logically internal, but is made public because it is used -// from protocol-compiler-generated code, which may reside in other components. - #ifndef GOOGLE_PROTOBUF_ARENA_H__ #define GOOGLE_PROTOBUF_ARENA_H__ +#if __cplusplus >= 201103L +#include <google/protobuf/stubs/type_traits.h> +#endif #include <typeinfo> #include <google/protobuf/stubs/atomic_sequence_num.h> @@ -113,10 +113,13 @@ struct ArenaOptions { void (*on_arena_reset)(Arena* arena, void* cookie, uint64 space_used); void (*on_arena_destruction)(Arena* arena, void* cookie, uint64 space_used); - // type_name is promised to be a static string - its lifetime extends to - // match program's lifetime. - void (*on_arena_allocation)(const char* type_name, uint64 alloc_size, - Arena* arena, void* cookie); + // type_info is promised to be static - its lifetime extends to + // match program's lifetime (It is given by typeid operator). + // Note: typeid(void) will be passed as allocated_type every time we + // intentionally want to avoid monitoring an allocation. (i.e. internal + // allocations for managing the arena) + void (*on_arena_allocation)(const std::type_info* allocated_type, + uint64 alloc_size, void* cookie); ArenaOptions() : start_block_size(kDefaultStartBlockSize), @@ -137,6 +140,14 @@ struct ArenaOptions { static const size_t kDefaultMaxBlockSize = 8192; }; +// Support for non-RTTI environments. (The metrics hooks API uses type +// information.) +#ifndef GOOGLE_PROTOBUF_NO_RTTI +#define RTTI_TYPE_ID(type) (&typeid(type)) +#else +#define RTTI_TYPE_ID(type) (NULL) +#endif + // Arena allocator. Arena allocation replaces ordinary (heap-based) allocation // with new/delete, and improves performance by aggregating allocations into // larger blocks and freeing allocations all at once. Protocol messages are @@ -146,6 +157,44 @@ struct ArenaOptions { // This is a thread-safe implementation: multiple threads may allocate from the // arena concurrently. Destruction is not thread-safe and the destructing // thread must synchronize with users of the arena first. +// +// An arena provides two allocation interfaces: CreateMessage<T>, which works +// for arena-enabled proto2 message types as well as other types that satisfy +// the appropriate protocol (described below), and Create<T>, which works for +// any arbitrary type T. CreateMessage<T> is better when the type T supports it, +// because this interface (i) passes the arena pointer to the created object so +// that its sub-objects and internal allocations can use the arena too, and (ii) +// elides the object's destructor call when possible. Create<T> does not place +// any special requirements on the type T, and will invoke the object's +// destructor when the arena is destroyed. +// +// The arena message allocation protocol, required by CreateMessage<T>, is as +// follows: +// +// - The type T must have (at least) two constructors: a constructor with no +// arguments, called when a T is allocated on the heap; and a constructor with +// a google::protobuf::Arena* argument, called when a T is allocated on an arena. If the +// second constructor is called with a NULL arena pointer, it must be +// equivalent to invoking the first (no-argument) constructor. +// +// - The type T must have a particular type trait: a nested type +// |InternalArenaConstructable_|. This is usually a typedef to |void|. If no +// such type trait exists, then the instantiation CreateMessage<T> will fail +// to compile. +// +// - The type T *may* have the type trait |DestructorSkippable_|. If this type +// trait is present in the type, then its destructor will not be called if and +// only if it was passed a non-NULL arena pointer. If this type trait is not +// present on the type, then its destructor is always called when the +// containing arena is destroyed. +// +// - One- and two-user-argument forms of CreateMessage<T>() also exist that +// forward these constructor arguments to T's constructor: for example, +// CreateMessage<T>(Arena*, arg1, arg2) forwards to a constructor T(Arena*, +// arg1, arg2). +// +// This protocol is implemented by all arena-enabled proto2 message classes as +// well as RepeatedPtrField. class LIBPROTOBUF_EXPORT Arena { public: // Arena constructor taking custom options. See ArenaOptions below for @@ -172,8 +221,10 @@ class LIBPROTOBUF_EXPORT Arena { // compilation error will occur. // // RepeatedField and RepeatedPtrField may also be instantiated directly on an - // arena with this method: they act as "arena-capable message types" for the - // purposes of the Arena API. + // arena with this method. + // + // This function also accepts any type T that satisfies the arena message + // allocation protocol, documented above. template <typename T> GOOGLE_ATTRIBUTE_ALWAYS_INLINE static T* CreateMessage(::google::protobuf::Arena* arena) { if (arena == NULL) { @@ -183,17 +234,55 @@ class LIBPROTOBUF_EXPORT Arena { } } + // One-argument form of CreateMessage. This is useful for constructing objects + // that implement the arena message construction protocol described above but + // take additional constructor arguments. + template <typename T, typename Arg> GOOGLE_ATTRIBUTE_ALWAYS_INLINE + static T* CreateMessage(::google::protobuf::Arena* arena, const Arg& arg) { + if (arena == NULL) { + return new T(NULL, arg); + } else { + return arena->CreateMessageInternal<T>(static_cast<T*>(0), + arg); + } + } + + // Two-argument form of CreateMessage. This is useful for constructing objects + // that implement the arena message construction protocol described above but + // take additional constructor arguments. + template <typename T, typename Arg1, typename Arg2> GOOGLE_ATTRIBUTE_ALWAYS_INLINE + static T* CreateMessage(::google::protobuf::Arena* arena, + const Arg1& arg1, + const Arg2& arg2) { + if (arena == NULL) { + return new T(NULL, arg1, arg2); + } else { + return arena->CreateMessageInternal<T>(static_cast<T*>(0), + arg1, arg2); + } + } + // API to create any objects on the arena. Note that only the object will // be created on the arena; the underlying ptrs (in case of a proto2 message) // will be still heap allocated. Proto messages should usually be allocated // with CreateMessage<T>() instead. + // + // Note that even if T satisfies the arena message construction protocol + // (InternalArenaConstructable_ trait and optional DestructorSkippable_ + // trait), as described above, this function does not follow the protocol; + // instead, it treats T as a black-box type, just as if it did not have these + // traits. Specifically, T's constructor arguments will always be only those + // passed to Create<T>() -- no additional arena pointer is implicitly added. + // Furthermore, the destructor will always be called at arena destruction time + // (unless the destructor is trivial). Hence, from T's point of view, it is as + // if the object were allocated on the heap (except that the underlying memory + // is obtained from the arena). template <typename T> GOOGLE_ATTRIBUTE_ALWAYS_INLINE static T* Create(::google::protobuf::Arena* arena) { if (arena == NULL) { return new T(); } else { - return arena->CreateInternal<T>( - SkipDeleteList<T>(static_cast<T*>(0))); + return arena->CreateInternal<T>(google::protobuf::internal::has_trivial_destructor<T>::value); } } @@ -203,7 +292,7 @@ class LIBPROTOBUF_EXPORT Arena { if (arena == NULL) { return new T(arg); } else { - return arena->CreateInternal<T>(SkipDeleteList<T>(static_cast<T*>(0)), + return arena->CreateInternal<T>(google::protobuf::internal::has_trivial_destructor<T>::value, arg); } } @@ -214,9 +303,8 @@ class LIBPROTOBUF_EXPORT Arena { if (arena == NULL) { return new T(arg1, arg2); } else { - return arena->CreateInternal<T>(SkipDeleteList<T>(static_cast<T*>(0)), - arg1, - arg2); + return arena->CreateInternal<T>(google::protobuf::internal::has_trivial_destructor<T>::value, + arg1, arg2); } } @@ -229,10 +317,8 @@ class LIBPROTOBUF_EXPORT Arena { if (arena == NULL) { return new T(arg1, arg2, arg3); } else { - return arena->CreateInternal<T>(SkipDeleteList<T>(static_cast<T*>(0)), - arg1, - arg2, - arg3); + return arena->CreateInternal<T>(google::protobuf::internal::has_trivial_destructor<T>::value, + arg1, arg2, arg3); } } @@ -246,20 +332,95 @@ class LIBPROTOBUF_EXPORT Arena { if (arena == NULL) { return new T(arg1, arg2, arg3, arg4); } else { - return arena->CreateInternal<T>(SkipDeleteList<T>(static_cast<T*>(0)), - arg1, - arg2, - arg3, - arg4); + return arena->CreateInternal<T>(google::protobuf::internal::has_trivial_destructor<T>::value, + arg1, arg2, arg3, arg4); } } - // Create an array of object type T on the arena. Type T must have a trivial - // constructor, as it will not be invoked when created on the arena. + // Version of the above with five constructor arguments for the created + // object. + template <typename T, typename Arg1, typename Arg2, typename Arg3, + typename Arg4, typename Arg5> + GOOGLE_ATTRIBUTE_ALWAYS_INLINE static T* Create(::google::protobuf::Arena* arena, + const Arg1& arg1, const Arg2& arg2, + const Arg3& arg3, const Arg4& arg4, + const Arg5& arg5) { + if (arena == NULL) { + return new T(arg1, arg2, arg3, arg4, arg5); + } else { + return arena->CreateInternal<T>(google::protobuf::internal::has_trivial_destructor<T>::value, + arg1, arg2, arg3, arg4, arg5); + } + } + + // Version of the above with six constructor arguments for the created + // object. + template <typename T, typename Arg1, typename Arg2, typename Arg3, + typename Arg4, typename Arg5, typename Arg6> + GOOGLE_ATTRIBUTE_ALWAYS_INLINE static T* Create(::google::protobuf::Arena* arena, + const Arg1& arg1, const Arg2& arg2, + const Arg3& arg3, const Arg4& arg4, + const Arg5& arg5, const Arg6& arg6) { + if (arena == NULL) { + return new T(arg1, arg2, arg3, arg4, arg5, arg6); + } else { + return arena->CreateInternal<T>(google::protobuf::internal::has_trivial_destructor<T>::value, + arg1, arg2, arg3, arg4, arg5, arg6); + } + } + + // Version of the above with seven constructor arguments for the created + // object. + template <typename T, typename Arg1, typename Arg2, typename Arg3, + typename Arg4, typename Arg5, typename Arg6, typename Arg7> + GOOGLE_ATTRIBUTE_ALWAYS_INLINE static T* Create(::google::protobuf::Arena* arena, + const Arg1& arg1, const Arg2& arg2, + const Arg3& arg3, const Arg4& arg4, + const Arg5& arg5, const Arg6& arg6, + const Arg7& arg7) { + if (arena == NULL) { + return new T(arg1, arg2, arg3, arg4, arg5, arg6, arg7); + } else { + return arena->CreateInternal<T>(google::protobuf::internal::has_trivial_destructor<T>::value, + arg1, arg2, arg3, arg4, arg5, arg6, arg7); + } + } + + // Version of the above with eight constructor arguments for the created + // object. + template <typename T, typename Arg1, typename Arg2, typename Arg3, + typename Arg4, typename Arg5, typename Arg6, typename Arg7, + typename Arg8> + GOOGLE_ATTRIBUTE_ALWAYS_INLINE static T* Create(::google::protobuf::Arena* arena, + const Arg1& arg1, const Arg2& arg2, + const Arg3& arg3, const Arg4& arg4, + const Arg5& arg5, const Arg6& arg6, + const Arg7& arg7, const Arg8& arg8) { + if (arena == NULL) { + return new T(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8); + } else { + return arena->CreateInternal<T>( + google::protobuf::internal::has_trivial_destructor<T>::value, + arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8); + } + } + + // Create an array of object type T on the arena *without* invoking the + // constructor of T. If `arena` is null, then the return value should be freed + // with `delete[] x;` (or `::operator delete[](x);`). + // To ensure safe uses, this function checks at compile time + // (when compiled as C++11) that T is trivially default-constructible and + // trivially destructible. template <typename T> GOOGLE_ATTRIBUTE_ALWAYS_INLINE static T* CreateArray(::google::protobuf::Arena* arena, size_t num_elements) { +#if __cplusplus >= 201103L + static_assert(std::is_trivially_default_constructible<T>::value, + "CreateArray requires a trivially constructible type"); + static_assert(std::is_trivially_destructible<T>::value, + "CreateArray requires a trivially destructible type"); +#endif if (arena == NULL) { - return new T[num_elements]; + return static_cast<T*>(::operator new[](num_elements * sizeof(T))); } else { return arena->CreateInternalRawArray<T>(num_elements); } @@ -374,27 +535,26 @@ class LIBPROTOBUF_EXPORT Arena { // wrap them in static functions. static ThreadCache& thread_cache(); #elif defined(GOOGLE_PROTOBUF_OS_ANDROID) || defined(GOOGLE_PROTOBUF_OS_IPHONE) - // Android ndk does not support __thread keyword so we use a custom thread + // Android ndk does not support GOOGLE_THREAD_LOCAL keyword so we use a custom thread // local storage class we implemented. - // iOS also does not support the __thread keyword. + // iOS also does not support the GOOGLE_THREAD_LOCAL keyword. static ThreadCache& thread_cache(); #else static GOOGLE_THREAD_LOCAL ThreadCache thread_cache_; static ThreadCache& thread_cache() { return thread_cache_; } #endif - // SFINAE for skipping addition to delete list for a Type. This is mainly to - // skip proto2/proto1 message objects with cc_enable_arenas=true from being - // part of the delete list. Also, note, compiler will optimize out the branch - // in CreateInternal<T>. - // + // SFINAE for skipping addition to delete list for a message type when created + // with CreateMessage. This is mainly to skip proto2/proto1 message objects + // with cc_enable_arenas=true from being part of the delete list. Also, note, + // compiler will optimize out the branch in CreateInternal<T>. template<typename T> static inline bool SkipDeleteList(typename T::DestructorSkippable_*) { return true; } - // For non message objects, we skip addition to delete list if the object has - // a trivial destructor. + // For message objects that don't have the DestructorSkippable_ trait, we + // always add to the delete list. template<typename T> static inline bool SkipDeleteList(...) { return google::protobuf::internal::has_trivial_destructor<T>::value; @@ -419,14 +579,15 @@ class LIBPROTOBUF_EXPORT Arena { // Just allocate the required size for the given type assuming the // type has a trivial constructor. template<typename T> GOOGLE_ATTRIBUTE_ALWAYS_INLINE - inline T* CreateInternalRawArray(uint32 num_elements) { - return static_cast<T*>(AllocateAligned(sizeof(T) * num_elements)); + inline T* CreateInternalRawArray(size_t num_elements) { + return static_cast<T*>( + AllocateAligned(RTTI_TYPE_ID(T), sizeof(T) * num_elements)); } template <typename T> GOOGLE_ATTRIBUTE_ALWAYS_INLINE inline T* CreateInternal( bool skip_explicit_ownership) { - T* t = new (AllocateAligned(sizeof(T))) T(); + T* t = new (AllocateAligned(RTTI_TYPE_ID(T), sizeof(T))) T(); if (!skip_explicit_ownership) { AddListNode(t, &internal::arena_destruct_object<T>); } @@ -436,7 +597,7 @@ class LIBPROTOBUF_EXPORT Arena { template <typename T, typename Arg> GOOGLE_ATTRIBUTE_ALWAYS_INLINE inline T* CreateInternal( bool skip_explicit_ownership, const Arg& arg) { - T* t = new (AllocateAligned(sizeof(T))) T(arg); + T* t = new (AllocateAligned(RTTI_TYPE_ID(T), sizeof(T))) T(arg); if (!skip_explicit_ownership) { AddListNode(t, &internal::arena_destruct_object<T>); } @@ -446,7 +607,7 @@ class LIBPROTOBUF_EXPORT Arena { template <typename T, typename Arg1, typename Arg2> GOOGLE_ATTRIBUTE_ALWAYS_INLINE inline T* CreateInternal( bool skip_explicit_ownership, const Arg1& arg1, const Arg2& arg2) { - T* t = new (AllocateAligned(sizeof(T))) T(arg1, arg2); + T* t = new (AllocateAligned(RTTI_TYPE_ID(T), sizeof(T))) T(arg1, arg2); if (!skip_explicit_ownership) { AddListNode(t, &internal::arena_destruct_object<T>); } @@ -458,7 +619,8 @@ class LIBPROTOBUF_EXPORT Arena { const Arg1& arg1, const Arg2& arg2, const Arg3& arg3) { - T* t = new (AllocateAligned(sizeof(T))) T(arg1, arg2, arg3); + T* t = new (AllocateAligned(RTTI_TYPE_ID(T), sizeof(T))) + T(arg1, arg2, arg3); if (!skip_explicit_ownership) { AddListNode(t, &internal::arena_destruct_object<T>); } @@ -472,7 +634,79 @@ class LIBPROTOBUF_EXPORT Arena { const Arg2& arg2, const Arg3& arg3, const Arg4& arg4) { - T* t = new (AllocateAligned(sizeof(T))) T(arg1, arg2, arg3, arg4); + T* t = new (AllocateAligned(RTTI_TYPE_ID(T), sizeof(T))) + T(arg1, arg2, arg3, arg4); + if (!skip_explicit_ownership) { + AddListNode(t, &internal::arena_destruct_object<T>); + } + return t; + } + + template <typename T, typename Arg1, typename Arg2, typename Arg3, + typename Arg4, typename Arg5> + GOOGLE_ATTRIBUTE_ALWAYS_INLINE inline T* CreateInternal(bool skip_explicit_ownership, + const Arg1& arg1, + const Arg2& arg2, + const Arg3& arg3, + const Arg4& arg4, + const Arg5& arg5) { + T* t = new (AllocateAligned(RTTI_TYPE_ID(T), sizeof(T))) + T(arg1, arg2, arg3, arg4, arg5); + if (!skip_explicit_ownership) { + AddListNode(t, &internal::arena_destruct_object<T>); + } + return t; + } + + template <typename T, typename Arg1, typename Arg2, typename Arg3, + typename Arg4, typename Arg5, typename Arg6> + GOOGLE_ATTRIBUTE_ALWAYS_INLINE inline T* CreateInternal(bool skip_explicit_ownership, + const Arg1& arg1, + const Arg2& arg2, + const Arg3& arg3, + const Arg4& arg4, + const Arg5& arg5, + const Arg6& arg6) { + T* t = new (AllocateAligned(RTTI_TYPE_ID(T), sizeof(T))) + T(arg1, arg2, arg3, arg4, arg5, arg6); + if (!skip_explicit_ownership) { + AddListNode(t, &internal::arena_destruct_object<T>); + } + return t; + } + + template <typename T, typename Arg1, typename Arg2, typename Arg3, + typename Arg4, typename Arg5, typename Arg6, typename Arg7> + GOOGLE_ATTRIBUTE_ALWAYS_INLINE inline T* CreateInternal(bool skip_explicit_ownership, + const Arg1& arg1, + const Arg2& arg2, + const Arg3& arg3, + const Arg4& arg4, + const Arg5& arg5, + const Arg6& arg6, + const Arg7& arg7) { + T* t = new (AllocateAligned(RTTI_TYPE_ID(T), sizeof(T))) + T(arg1, arg2, arg3, arg4, arg5, arg6, arg7); + if (!skip_explicit_ownership) { + AddListNode(t, &internal::arena_destruct_object<T>); + } + return t; + } + + template <typename T, typename Arg1, typename Arg2, typename Arg3, + typename Arg4, typename Arg5, typename Arg6, typename Arg7, + typename Arg8> + GOOGLE_ATTRIBUTE_ALWAYS_INLINE inline T* CreateInternal(bool skip_explicit_ownership, + const Arg1& arg1, + const Arg2& arg2, + const Arg3& arg3, + const Arg4& arg4, + const Arg5& arg5, + const Arg6& arg6, + const Arg7& arg7, + const Arg8& arg8) { + T* t = new (AllocateAligned(RTTI_TYPE_ID(T), sizeof(T))) + T(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8); if (!skip_explicit_ownership) { AddListNode(t, &internal::arena_destruct_object<T>); } @@ -485,6 +719,20 @@ class LIBPROTOBUF_EXPORT Arena { this); } + template <typename T, typename Arg> GOOGLE_ATTRIBUTE_ALWAYS_INLINE + inline T* CreateMessageInternal(typename T::InternalArenaConstructable_*, + const Arg& arg) { + return CreateInternal<T, Arena*>(SkipDeleteList<T>(static_cast<T*>(0)), + this, arg); + } + + template <typename T, typename Arg1, typename Arg2> GOOGLE_ATTRIBUTE_ALWAYS_INLINE + inline T* CreateMessageInternal(typename T::InternalArenaConstructable_*, + const Arg1& arg1, const Arg2& arg2) { + return CreateInternal<T, Arena*>(SkipDeleteList<T>(static_cast<T*>(0)), + this, arg1, arg2); + } + // CreateInArenaStorage is used to implement map field. Without it, // google::protobuf::Map need to call generated message's protected arena constructor, // which needs to declare google::protobuf::Map as friend of generated message. @@ -536,8 +784,15 @@ class LIBPROTOBUF_EXPORT Arena { return NULL; } + // Allocate and also optionally call on_arena_allocation callback with the + // allocated type info when the hooks are in place in ArenaOptions and + // the cookie is not null. + void* AllocateAligned(const std::type_info* allocated, size_t n); - void* AllocateAligned(size_t size); + // Allocate an internal allocation, avoiding optional typed monitoring. + GOOGLE_ATTRIBUTE_ALWAYS_INLINE inline void* AllocateAligned(size_t n) { + return AllocateAligned(NULL, n); + } void Init(); @@ -596,6 +851,9 @@ class LIBPROTOBUF_EXPORT Arena { GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(Arena); }; +// Defined above for supporting environments without RTTI. +#undef RTTI_TYPE_ID + template<typename T> const typename Arena::is_arena_constructable<T>::type Arena::is_arena_constructable<T>::value = |