third_party/protobuf: Update to HEAD (83d681ee2c)

third_party/protobuf/src/google/protobuf/io/coded_stream.h

Index: third_party/protobuf/src/google/protobuf/io/coded_stream.h
diff --git a/third_party/protobuf/src/google/protobuf/io/coded_stream.h b/third_party/protobuf/src/google/protobuf/io/coded_stream.h
index c81a33ac6b25c459819fa4c48a0b885675e194cf..1402cc170de6b789691d13968ae396fa592527b3 100644
--- a/third_party/protobuf/src/google/protobuf/io/coded_stream.h
+++ b/third_party/protobuf/src/google/protobuf/io/coded_stream.h
@@ -237,6 +237,17 @@ class LIBPROTOBUF_EXPORT CodedInputStream {
   // Read an unsigned integer with Varint encoding.
   bool ReadVarint64(uint64* value);
 
+  // Reads a varint off the wire into an "int". This should be used for reading
+  // sizes off the wire (sizes of strings, submessages, bytes fields, etc).
+  //
+  // The value from the wire is interpreted as unsigned.  If its value exceeds
+  // the representable value of an integer on this platform, instead of
+  // truncating we return false. Truncating (as performed by ReadVarint32()
+  // above) is an acceptable approach for fields representing an integer, but
+  // when we are parsing a size from the wire, truncating the value would result
+  // in us misparsing the payload.
+  bool ReadVarintSizeAsInt(int* value);
+
   // Read a tag.  This calls ReadVarint32() and returns the result, or returns
   // zero (which is not a valid tag) if ReadVarint32() fails.  Also, it updates
   // the last tag value, which can be checked with LastTagWas().
@@ -594,9 +605,11 @@ class LIBPROTOBUF_EXPORT CodedInputStream {
   // if it fails and the uint32 it read otherwise.  The latter has a bool
   // indicating success or failure as part of its return type.
   int64 ReadVarint32Fallback(uint32 first_byte_or_zero);
+  int ReadVarintSizeAsIntFallback();
   std::pair<uint64, bool> ReadVarint64Fallback();
   bool ReadVarint32Slow(uint32* value);
   bool ReadVarint64Slow(uint64* value);
+  int ReadVarintSizeAsIntSlow();
   bool ReadLittleEndian32Fallback(uint32* value);
   bool ReadLittleEndian64Fallback(uint64* value);
   // Fallback/slow methods for reading tags. These do not update last_tag_,
@@ -771,17 +784,17 @@ class LIBPROTOBUF_EXPORT CodedOutputStream {
                                                         uint8* target);
 
   // Returns the number of bytes needed to encode the given value as a varint.
-  static int VarintSize32(uint32 value);
+  static size_t VarintSize32(uint32 value);
   // Returns the number of bytes needed to encode the given value as a varint.
-  static int VarintSize64(uint64 value);
+  static size_t VarintSize64(uint64 value);
 
   // If negative, 10 bytes.  Otheriwse, same as VarintSize32().
-  static int VarintSize32SignExtended(int32 value);
+  static size_t VarintSize32SignExtended(int32 value);
 
   // Compile-time equivalent of VarintSize32().
   template <uint32 Value>
   struct StaticVarintSize32 {
-    static const int value =
+    static const size_t value =
         (Value < (1 << 7))
             ? 1
             : (Value < (1 << 14))
@@ -800,6 +813,44 @@ class LIBPROTOBUF_EXPORT CodedOutputStream {
   // created.
   bool HadError() const { return had_error_; }
 
+  // Deterministic serialization, if requested, guarantees that for a given
+  // binary, equal messages will always be serialized to the same bytes. This
+  // implies:
+  //   . repeated serialization of a message will return the same bytes
+  //   . different processes of the same binary (which may be executing on
+  //     different machines) will serialize equal messages to the same bytes.
+  //
+  // Note the deterministic serialization is NOT canonical across languages; it
+  // is also unstable across different builds with schema changes due to unknown
+  // fields. Users who need canonical serialization, e.g., persistent storage in
+  // a canonical form, fingerprinting, etc., should define their own
+  // canonicalization specification and implement the serializer using
+  // reflection APIs rather than relying on this API.
+  //
+  // If determinisitc serialization is requested, the serializer will
+  // sort map entries by keys in lexicographical order or numerical order.
+  // (This is an implementation detail and may subject to change.)
+  //
+  // There are two ways to determine whether serialization should be
+  // deterministic for this CodedOutputStream.  If SetSerializationDeterministic
+  // has not yet been called, then the default comes from the global default,
+  // which is false, until SetDefaultSerializationDeterministic has been called.
+  // Otherwise, SetSerializationDeterministic has been called, and the last
+  // value passed to it is all that matters.
+  void SetSerializationDeterministic(bool value) {
+    serialization_deterministic_is_overridden_ = true;
+    serialization_deterministic_override_ = value;
+  }
+  // See above.  Also, note that users of this CodedOutputStream may need to
+  // call IsSerializationDeterminstic() to serialize in the intended way.  This
+  // CodedOutputStream cannot enforce a desire for deterministic serialization
+  // by itself.
+  bool IsSerializationDeterminstic() const {
+    return serialization_deterministic_is_overridden_ ?
+        serialization_deterministic_override_ :
+        default_serialization_deterministic_;
+  }
+
  private:
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(CodedOutputStream);
 
@@ -809,6 +860,10 @@ class LIBPROTOBUF_EXPORT CodedOutputStream {
   int total_bytes_;  // Sum of sizes of all buffers seen so far.
   bool had_error_;   // Whether an error occurred during output.
   bool aliasing_enabled_;  // See EnableAliasing().
+  // See SetSerializationDeterministic() regarding these three fields.
+  bool serialization_deterministic_is_overridden_;
+  bool serialization_deterministic_override_;
+  static bool default_serialization_deterministic_;
 
   // Advance the buffer by a given number of bytes.
   void Advance(int amount);
@@ -835,7 +890,12 @@ class LIBPROTOBUF_EXPORT CodedOutputStream {
   GOOGLE_ATTRIBUTE_ALWAYS_INLINE static uint8* WriteVarint64ToArrayInline(
       uint64 value, uint8* target);
 
-  static int VarintSize32Fallback(uint32 value);
+  static size_t VarintSize32Fallback(uint32 value);
+
+  // See above.  Other projects may use "friend" to allow them to call this.
+  static void SetDefaultSerializationDeterministic() {
+    default_serialization_deterministic_ = true;
+  }
 };
 
 // inline methods ====================================================
@@ -868,6 +928,19 @@ inline bool CodedInputStream::ReadVarint64(uint64* value) {
   return p.second;
 }
 
+inline bool CodedInputStream::ReadVarintSizeAsInt(int* value) {
+  if (GOOGLE_PREDICT_TRUE(buffer_ < buffer_end_)) {
+    int v = *buffer_;
+    if (v < 0x80) {
+      *value = v;
+      Advance(1);
+      return true;
+    }
+  }
+  *value = ReadVarintSizeAsIntFallback();
+  return *value >= 0;
+}
+
 // static
 inline const uint8* CodedInputStream::ReadLittleEndian32FromArray(
     const uint8* buffer,
@@ -1152,7 +1225,7 @@ inline uint8* CodedOutputStream::WriteTagToArray(
   return WriteVarint32ToArray(value, target);
 }
 
-inline int CodedOutputStream::VarintSize32(uint32 value) {
+inline size_t CodedOutputStream::VarintSize32(uint32 value) {
   if (value < (1 << 7)) {
     return 1;
   } else  {
@@ -1160,7 +1233,7 @@ inline int CodedOutputStream::VarintSize32(uint32 value) {
   }
 }
 
-inline int CodedOutputStream::VarintSize32SignExtended(int32 value) {
+inline size_t CodedOutputStream::VarintSize32SignExtended(int32 value) {
   if (value < 0) {
     return 10;     // TODO(kenton):  Make this a symbolic constant.
   } else {