diff options
Diffstat (limited to 'src/google/protobuf/message_lite.h')
| -rw-r--r-- | src/google/protobuf/message_lite.h | 225 |
1 files changed, 190 insertions, 35 deletions
diff --git a/src/google/protobuf/message_lite.h b/src/google/protobuf/message_lite.h index 4c16f4c0..4cbec330 100644 --- a/src/google/protobuf/message_lite.h +++ b/src/google/protobuf/message_lite.h @@ -39,19 +39,113 @@ #ifndef GOOGLE_PROTOBUF_MESSAGE_LITE_H__ #define GOOGLE_PROTOBUF_MESSAGE_LITE_H__ +#include <climits> #include <google/protobuf/stubs/common.h> - +#include <google/protobuf/stubs/logging.h> +#include <google/protobuf/stubs/once.h> +#include <google/protobuf/arena.h> +#include <google/protobuf/stubs/port.h> namespace google { namespace protobuf { - class Arena; +template <typename T> +class RepeatedPtrField; namespace io { - class CodedInputStream; - class CodedOutputStream; - class ZeroCopyInputStream; - class ZeroCopyOutputStream; +class CodedInputStream; +class CodedOutputStream; +class ZeroCopyInputStream; +class ZeroCopyOutputStream; +} +namespace internal { + +class RepeatedPtrFieldBase; +class WireFormatLite; +class WeakFieldMap; + +#ifndef SWIG +// We compute sizes as size_t but cache them as int. This function converts a +// computed size to a cached size. Since we don't proceed with serialization +// if the total size was > INT_MAX, it is not important what this function +// returns for inputs > INT_MAX. However this case should not error or +// GOOGLE_CHECK-fail, because the full size_t resolution is still returned from +// ByteSizeLong() and checked against INT_MAX; we can catch the overflow +// there. +inline int ToCachedSize(size_t size) { return static_cast<int>(size); } + +// We mainly calculate sizes in terms of size_t, but some functions that +// compute sizes return "int". These int sizes are expected to always be +// positive. This function is more efficient than casting an int to size_t +// directly on 64-bit platforms because it avoids making the compiler emit a +// sign extending instruction, which we don't want and don't want to pay for. +inline size_t FromIntSize(int size) { + // Convert to unsigned before widening so sign extension is not necessary. + return static_cast<unsigned int>(size); +} + +// For cases where a legacy function returns an integer size. We GOOGLE_DCHECK() +// that the conversion will fit within an integer; if this is false then we +// are losing information. +inline int ToIntSize(size_t size) { + GOOGLE_DCHECK_LE(size, static_cast<size_t>(INT_MAX)); + return static_cast<int>(size); +} + +// This type wraps a variable whose constructor and destructor are explicitly +// called. It is particularly useful for a global variable, without its +// constructor and destructor run on start and end of the program lifetime. +// This circumvents the initial construction order fiasco, while keeping +// the address of the empty string a compile time constant. +// +// Pay special attention to the initialization state of the object. +// 1. The object is "uninitialized" to begin with. +// 2. Call DefaultConstruct() only if the object is uninitialized. +// After the call, the object becomes "initialized". +// 3. Call get() and get_mutable() only if the object is initialized. +// 4. Call Destruct() only if the object is initialized. +// After the call, the object becomes uninitialized. +template <typename T> +class ExplicitlyConstructed { + public: + void DefaultConstruct() { + new (&union_) T(); + } + + void Destruct() { + get_mutable()->~T(); + } + + constexpr const T& get() const { return reinterpret_cast<const T&>(union_); } + T* get_mutable() { return reinterpret_cast<T*>(&union_); } + + private: + // Prefer c++14 aligned_storage, but for compatibility this will do. + union AlignedUnion { + char space[sizeof(T)]; + int64 align_to_int64; + void* align_to_ptr; + } union_; +}; + +// Default empty string object. Don't use this directly. Instead, call +// GetEmptyString() to get the reference. +LIBPROTOBUF_EXPORT extern ExplicitlyConstructed<::std::string> fixed_address_empty_string; +LIBPROTOBUF_EXPORT extern ProtobufOnceType empty_string_once_init_; +LIBPROTOBUF_EXPORT void InitEmptyString(); + + +LIBPROTOBUF_EXPORT inline const ::std::string& GetEmptyStringAlreadyInited() { + return fixed_address_empty_string.get(); } +LIBPROTOBUF_EXPORT inline const ::std::string& GetEmptyString() { + ::google::protobuf::GoogleOnceInit(&empty_string_once_init_, &InitEmptyString); + return GetEmptyStringAlreadyInited(); +} + +LIBPROTOBUF_EXPORT size_t StringSpaceUsedExcludingSelfLong(const string& str); +#endif // SWIG +} // namespace internal + // Interface to light weight protocol messages. // // This interface is implemented by all protocol message objects. Non-lite @@ -78,7 +172,7 @@ namespace io { class LIBPROTOBUF_EXPORT MessageLite { public: inline MessageLite() {} - virtual ~MessageLite(); + virtual ~MessageLite() {} // Basic Operations ------------------------------------------------ @@ -96,18 +190,19 @@ class LIBPROTOBUF_EXPORT MessageLite { // Get the arena, if any, associated with this message. Virtual method // required for generic operations but most arena-related operations should // use the GetArenaNoVirtual() generated-code method. Default implementation - // to reduce code size by avoiding the need for per-type implementations when - // types do not implement arena support. + // to reduce code size by avoiding the need for per-type implementations + // when types do not implement arena support. virtual ::google::protobuf::Arena* GetArena() const { return NULL; } - // Get a pointer that may be equal to this message's arena, or may not be. If - // the value returned by this method is equal to some arena pointer, then this - // message is on that arena; however, if this message is on some arena, this - // method may or may not return that arena's pointer. As a tradeoff, this - // method may be more efficient than GetArena(). The intent is to allow - // underlying representations that use e.g. tagged pointers to sometimes store - // the arena pointer directly, and sometimes in a more indirect way, and allow - // a fastpath comparison against the arena pointer when it's easy to obtain. + // Get a pointer that may be equal to this message's arena, or may not be. + // If the value returned by this method is equal to some arena pointer, then + // this message is on that arena; however, if this message is on some arena, + // this method may or may not return that arena's pointer. As a tradeoff, + // this method may be more efficient than GetArena(). The intent is to allow + // underlying representations that use e.g. tagged pointers to sometimes + // store the arena pointer directly, and sometimes in a more indirect way, + // and allow a fastpath comparison against the arena pointer when it's easy + // to obtain. virtual void* GetMaybeArenaPointer() const { return GetArena(); } // Clear all fields of the message and set them to their default values. @@ -125,19 +220,20 @@ class LIBPROTOBUF_EXPORT MessageLite { // for full messages. See message.h. virtual string InitializationErrorString() const; - // If |other| is the exact same class as this, calls MergeFrom(). Otherwise, + // If |other| is the exact same class as this, calls MergeFrom(). Otherwise, // results are undefined (probably crash). virtual void CheckTypeAndMergeFrom(const MessageLite& other) = 0; // Parsing --------------------------------------------------------- // Methods for parsing in protocol buffer format. Most of these are - // just simple wrappers around MergeFromCodedStream(). Clear() will be called - // before merging the input. - - // Fill the message with a protocol buffer parsed from the given input stream. - // Returns false on a read error or if the input is in the wrong format. A - // successful return does not indicate the entire input is consumed, ensure - // you call ConsumedEntireMessage() to check that if applicable. + // just simple wrappers around MergeFromCodedStream(). Clear() will be + // called before merging the input. + + // Fill the message with a protocol buffer parsed from the given input + // stream. Returns false on a read error or if the input is in the wrong + // format. A successful return does not indicate the entire input is + // consumed, ensure you call ConsumedEntireMessage() to check that if + // applicable. bool ParseFromCodedStream(io::CodedInputStream* input); // Like ParseFromCodedStream(), but accepts messages that are missing // required fields. @@ -173,7 +269,7 @@ class LIBPROTOBUF_EXPORT MessageLite { // Reads a protocol buffer from the stream and merges it into this - // Message. Singular fields read from the input overwrite what is + // Message. Singular fields read from the what is // already in the Message and repeated fields are appended to those // already present. // @@ -236,22 +332,34 @@ class LIBPROTOBUF_EXPORT MessageLite { bool AppendPartialToString(string* output) const; // Computes the serialized size of the message. This recursively calls - // ByteSize() on all embedded messages. If a subclass does not override - // this, it MUST override SetCachedSize(). + // ByteSizeLong() on all embedded messages. // - // ByteSize() is generally linear in the number of fields defined for the + // ByteSizeLong() is generally linear in the number of fields defined for the // proto. - virtual int ByteSize() const = 0; + virtual size_t ByteSizeLong() const = 0; - // Serializes the message without recomputing the size. The message must - // not have changed since the last call to ByteSize(); if it has, the results - // are undefined. + // Legacy ByteSize() API. + PROTOBUF_RUNTIME_DEPRECATED("Please use ByteSizeLong() instead") + int ByteSize() const { + return internal::ToIntSize(ByteSizeLong()); + } + + // Serializes the message without recomputing the size. The message must not + // have changed since the last call to ByteSize(), and the value returned by + // ByteSize must be non-negative. Otherwise the results are undefined. virtual void SerializeWithCachedSizes( - io::CodedOutputStream* output) const = 0; + io::CodedOutputStream* output) const; + + // Functions below here are not part of the public interface. It isn't + // enforced, but they should be treated as private, and will be private + // at some future time. Unfortunately the implementation of the "friend" + // keyword in GCC is broken at the moment, but we expect it will be fixed. // Like SerializeWithCachedSizes, but writes directly to *target, returning // a pointer to the byte immediately after the last byte written. "target" - // must point at a byte array of at least ByteSize() bytes. + // must point at a byte array of at least ByteSize() bytes. Whether to use + // deterministic serialization, e.g., maps in sorted order, is determined by + // CodedOutputStream::IsDefaultSerializationDeterministic(). virtual uint8* SerializeWithCachedSizesToArray(uint8* target) const; // Returns the result of the last call to ByteSize(). An embedded message's @@ -267,10 +375,57 @@ class LIBPROTOBUF_EXPORT MessageLite { // method.) virtual int GetCachedSize() const = 0; + virtual uint8* InternalSerializeWithCachedSizesToArray(bool deterministic, + uint8* target) const; + + protected: + // CastToBase allows generated code to cast a RepeatedPtrField<T> to + // RepeatedPtrFieldBase. We try to restrict access to RepeatedPtrFieldBase + // because it is an implementation detail that user code should not access + // directly. + template <typename T> + static ::google::protobuf::internal::RepeatedPtrFieldBase* CastToBase( + ::google::protobuf::RepeatedPtrField<T>* repeated) { + return repeated; + } + template <typename T> + static const ::google::protobuf::internal::RepeatedPtrFieldBase& CastToBase( + const ::google::protobuf::RepeatedPtrField<T>& repeated) { + return repeated; + } + + template <typename T> + static T* CreateMaybeMessage(Arena* arena) { + return Arena::CreateMaybeMessage<T>(arena); + } + private: + // TODO(gerbens) make this a pure abstract function + virtual const void* InternalGetTable() const { return NULL; } + + friend class internal::WireFormatLite; + friend class Message; + friend class internal::WeakFieldMap; + GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(MessageLite); }; +namespace internal { + +extern bool LIBPROTOBUF_EXPORT proto3_preserve_unknown_; + +// DO NOT USE: For migration only. Will be removed when Proto3 defaults to +// preserve unknowns. +inline bool GetProto3PreserveUnknownsDefault() { + return proto3_preserve_unknown_; +} + +// DO NOT USE: For migration only. Will be removed when Proto3 defaults to +// preserve unknowns. +void LIBPROTOBUF_EXPORT SetProto3PreserveUnknownsDefault(bool preserve); +} // namespace internal + + } // namespace protobuf } // namespace google |