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1 // Protocol Buffers - Google's data interchange format
2 // Copyright 2008 Google Inc.  All rights reserved.
3 // https://developers.google.com/protocol-buffers/
4 //
5 // Redistribution and use in source and binary forms, with or without
6 // modification, are permitted provided that the following conditions are
7 // met:
8 //
9 //     * Redistributions of source code must retain the above copyright
10 // notice, this list of conditions and the following disclaimer.
11 //     * Redistributions in binary form must reproduce the above
12 // copyright notice, this list of conditions and the following disclaimer
13 // in the documentation and/or other materials provided with the
14 // distribution.
15 //     * Neither the name of Google Inc. nor the names of its
16 // contributors may be used to endorse or promote products derived from
17 // this software without specific prior written permission.
18 //
19 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 
31 // Authors: wink@google.com (Wink Saville),
32 //          kenton@google.com (Kenton Varda)
33 //  Based on original Protocol Buffers design by
34 //  Sanjay Ghemawat, Jeff Dean, and others.
35 
36 #include <google/protobuf/message_lite.h>
37 
38 #include <climits>
39 #include <cstdint>
40 #include <string>
41 
42 #include <google/protobuf/stubs/logging.h>
43 #include <google/protobuf/stubs/common.h>
44 #include <google/protobuf/stubs/stringprintf.h>
45 #include <google/protobuf/parse_context.h>
46 #include <google/protobuf/io/coded_stream.h>
47 #include <google/protobuf/io/zero_copy_stream.h>
48 #include <google/protobuf/io/zero_copy_stream_impl.h>
49 #include <google/protobuf/io/zero_copy_stream_impl_lite.h>
50 #include <google/protobuf/arena.h>
51 #include <google/protobuf/generated_message_table_driven.h>
52 #include <google/protobuf/generated_message_util.h>
53 #include <google/protobuf/repeated_field.h>
54 
55 #include <google/protobuf/stubs/strutil.h>
56 #include <google/protobuf/stubs/stl_util.h>
57 
58 #include <google/protobuf/port_def.inc>
59 
60 namespace google {
61 namespace protobuf {
62 
InitializationErrorString() const63 std::string MessageLite::InitializationErrorString() const {
64   return "(cannot determine missing fields for lite message)";
65 }
66 
DebugString() const67 std::string MessageLite::DebugString() const {
68   std::uintptr_t address = reinterpret_cast<std::uintptr_t>(this);
69   return StrCat("MessageLite at 0x", strings::Hex(address));
70 }
71 
72 namespace {
73 
74 // When serializing, we first compute the byte size, then serialize the message.
75 // If serialization produces a different number of bytes than expected, we
76 // call this function, which crashes.  The problem could be due to a bug in the
77 // protobuf implementation but is more likely caused by concurrent modification
78 // of the message.  This function attempts to distinguish between the two and
79 // provide a useful error message.
ByteSizeConsistencyError(size_t byte_size_before_serialization,size_t byte_size_after_serialization,size_t bytes_produced_by_serialization,const MessageLite & message)80 void ByteSizeConsistencyError(size_t byte_size_before_serialization,
81                               size_t byte_size_after_serialization,
82                               size_t bytes_produced_by_serialization,
83                               const MessageLite& message) {
84   GOOGLE_CHECK_EQ(byte_size_before_serialization, byte_size_after_serialization)
85       << message.GetTypeName()
86       << " was modified concurrently during serialization.";
87   GOOGLE_CHECK_EQ(bytes_produced_by_serialization, byte_size_before_serialization)
88       << "Byte size calculation and serialization were inconsistent.  This "
89          "may indicate a bug in protocol buffers or it may be caused by "
90          "concurrent modification of "
91       << message.GetTypeName() << ".";
92   GOOGLE_LOG(FATAL) << "This shouldn't be called if all the sizes are equal.";
93 }
94 
InitializationErrorMessage(const char * action,const MessageLite & message)95 std::string InitializationErrorMessage(const char* action,
96                                        const MessageLite& message) {
97   // Note:  We want to avoid depending on strutil in the lite library, otherwise
98   //   we'd use:
99   //
100   // return strings::Substitute(
101   //   "Can't $0 message of type \"$1\" because it is missing required "
102   //   "fields: $2",
103   //   action, message.GetTypeName(),
104   //   message.InitializationErrorString());
105 
106   std::string result;
107   result += "Can't ";
108   result += action;
109   result += " message of type \"";
110   result += message.GetTypeName();
111   result += "\" because it is missing required fields: ";
112   result += message.InitializationErrorString();
113   return result;
114 }
115 
as_string_view(const void * data,int size)116 inline StringPiece as_string_view(const void* data, int size) {
117   return StringPiece(static_cast<const char*>(data), size);
118 }
119 
120 }  // namespace
121 
LogInitializationErrorMessage() const122 void MessageLite::LogInitializationErrorMessage() const {
123   GOOGLE_LOG(ERROR) << InitializationErrorMessage("parse", *this);
124 }
125 
126 namespace internal {
127 
128 #if GOOGLE_PROTOBUF_ENABLE_EXPERIMENTAL_PARSER
129 
130 template <bool aliasing>
MergePartialFromImpl(StringPiece input,MessageLite * msg)131 bool MergePartialFromImpl(StringPiece input, MessageLite* msg) {
132   const char* ptr;
133   internal::ParseContext ctx(io::CodedInputStream::GetDefaultRecursionLimit(),
134                              aliasing, &ptr, input);
135   ptr = msg->_InternalParse(ptr, &ctx);
136   // ctx has an explicit limit set (length of string_view).
137   return ptr && ctx.EndedAtLimit();
138 }
139 
140 template <bool aliasing>
MergePartialFromImpl(io::ZeroCopyInputStream * input,MessageLite * msg)141 bool MergePartialFromImpl(io::ZeroCopyInputStream* input, MessageLite* msg) {
142   const char* ptr;
143   internal::ParseContext ctx(io::CodedInputStream::GetDefaultRecursionLimit(),
144                              aliasing, &ptr, input);
145   ptr = msg->_InternalParse(ptr, &ctx);
146   // ctx has no explicit limit (hence we end on end of stream)
147   return ptr && ctx.EndedAtEndOfStream();
148 }
149 
150 template <bool aliasing>
MergePartialFromImpl(BoundedZCIS input,MessageLite * msg)151 bool MergePartialFromImpl(BoundedZCIS input, MessageLite* msg) {
152   const char* ptr;
153   internal::ParseContext ctx(io::CodedInputStream::GetDefaultRecursionLimit(),
154                              aliasing, &ptr, input.zcis, input.limit);
155   ptr = msg->_InternalParse(ptr, &ctx);
156   if (PROTOBUF_PREDICT_FALSE(!ptr)) return false;
157   ctx.BackUp(ptr);
158   return ctx.EndedAtLimit();
159 }
160 
161 #else  // !GOOGLE_PROTOBUF_ENABLE_EXPERIMENTAL_PARSER
162 
163 inline bool InlineMergePartialEntireStream(io::CodedInputStream* cis,
164                                            MessageLite* message,
165                                            bool aliasing) {
166   return message->MergePartialFromCodedStream(cis) &&
167          cis->ConsumedEntireMessage();
168 }
169 
170 template <bool aliasing>
171 bool MergePartialFromImpl(StringPiece input, MessageLite* msg) {
172   io::CodedInputStream decoder(reinterpret_cast<const uint8*>(input.data()),
173                                input.size());
174   return InlineMergePartialEntireStream(&decoder, msg, aliasing);
175 }
176 
177 template <bool aliasing>
178 bool MergePartialFromImpl(BoundedZCIS input, MessageLite* msg) {
179   io::CodedInputStream decoder(input.zcis);
180   decoder.PushLimit(input.limit);
181   return InlineMergePartialEntireStream(&decoder, msg, aliasing) &&
182          decoder.BytesUntilLimit() == 0;
183 }
184 
185 template <bool aliasing>
186 bool MergePartialFromImpl(io::ZeroCopyInputStream* input, MessageLite* msg) {
187   io::CodedInputStream decoder(input);
188   return InlineMergePartialEntireStream(&decoder, msg, aliasing);
189 }
190 
191 #endif  // !GOOGLE_PROTOBUF_ENABLE_EXPERIMENTAL_PARSER
192 
193 template bool MergePartialFromImpl<false>(StringPiece input,
194                                           MessageLite* msg);
195 template bool MergePartialFromImpl<true>(StringPiece input,
196                                          MessageLite* msg);
197 template bool MergePartialFromImpl<false>(io::ZeroCopyInputStream* input,
198                                           MessageLite* msg);
199 template bool MergePartialFromImpl<true>(io::ZeroCopyInputStream* input,
200                                          MessageLite* msg);
201 template bool MergePartialFromImpl<false>(BoundedZCIS input, MessageLite* msg);
202 template bool MergePartialFromImpl<true>(BoundedZCIS input, MessageLite* msg);
203 
204 }  // namespace internal
205 
New(Arena * arena) const206 MessageLite* MessageLite::New(Arena* arena) const {
207   MessageLite* message = New();
208   if (arena != NULL) {
209     arena->Own(message);
210   }
211   return message;
212 }
213 
214 #if GOOGLE_PROTOBUF_ENABLE_EXPERIMENTAL_PARSER
215 class ZeroCopyCodedInputStream : public io::ZeroCopyInputStream {
216  public:
ZeroCopyCodedInputStream(io::CodedInputStream * cis)217   ZeroCopyCodedInputStream(io::CodedInputStream* cis) : cis_(cis) {}
Next(const void ** data,int * size)218   bool Next(const void** data, int* size) final {
219     if (!cis_->GetDirectBufferPointer(data, size)) return false;
220     cis_->Skip(*size);
221     return true;
222   }
BackUp(int count)223   void BackUp(int count) final { cis_->Advance(-count); }
Skip(int count)224   bool Skip(int count) final { return cis_->Skip(count); }
ByteCount() const225   int64 ByteCount() const final { return 0; }
226 
aliasing_enabled()227   bool aliasing_enabled() { return cis_->aliasing_enabled_; }
228 
229  private:
230   io::CodedInputStream* cis_;
231 };
232 
MergePartialFromCodedStream(io::CodedInputStream * input)233 bool MessageLite::MergePartialFromCodedStream(io::CodedInputStream* input) {
234   ZeroCopyCodedInputStream zcis(input);
235   const char* ptr;
236   internal::ParseContext ctx(input->RecursionBudget(), zcis.aliasing_enabled(),
237                              &ptr, &zcis);
238   // MergePartialFromCodedStream allows terminating the wireformat by 0 or
239   // end-group tag. Leaving it up to the caller to verify correct ending by
240   // calling LastTagWas on input. We need to maintain this behavior.
241   ctx.TrackCorrectEnding();
242   ctx.data().pool = input->GetExtensionPool();
243   ctx.data().factory = input->GetExtensionFactory();
244   ptr = _InternalParse(ptr, &ctx);
245   if (PROTOBUF_PREDICT_FALSE(!ptr)) return false;
246   ctx.BackUp(ptr);
247   if (!ctx.EndedAtEndOfStream()) {
248     GOOGLE_DCHECK(ctx.LastTag() != 1);  // We can't end on a pushed limit.
249     if (ctx.IsExceedingLimit(ptr)) return false;
250     input->SetLastTag(ctx.LastTag());
251     return true;
252   }
253   input->SetConsumed();
254   return true;
255 }
256 #endif  // GOOGLE_PROTOBUF_ENABLE_EXPERIMENTAL_PARSER
257 
MergeFromCodedStream(io::CodedInputStream * input)258 bool MessageLite::MergeFromCodedStream(io::CodedInputStream* input) {
259   return MergePartialFromCodedStream(input) && IsInitializedWithErrors();
260 }
261 
ParseFromCodedStream(io::CodedInputStream * input)262 bool MessageLite::ParseFromCodedStream(io::CodedInputStream* input) {
263   Clear();
264   return MergeFromCodedStream(input);
265 }
266 
ParsePartialFromCodedStream(io::CodedInputStream * input)267 bool MessageLite::ParsePartialFromCodedStream(io::CodedInputStream* input) {
268   Clear();
269   return MergePartialFromCodedStream(input);
270 }
271 
ParseFromZeroCopyStream(io::ZeroCopyInputStream * input)272 bool MessageLite::ParseFromZeroCopyStream(io::ZeroCopyInputStream* input) {
273   return ParseFrom<kParse>(input);
274 }
275 
ParsePartialFromZeroCopyStream(io::ZeroCopyInputStream * input)276 bool MessageLite::ParsePartialFromZeroCopyStream(
277     io::ZeroCopyInputStream* input) {
278   return ParseFrom<kParsePartial>(input);
279 }
280 
ParseFromFileDescriptor(int file_descriptor)281 bool MessageLite::ParseFromFileDescriptor(int file_descriptor) {
282   io::FileInputStream input(file_descriptor);
283   return ParseFromZeroCopyStream(&input) && input.GetErrno() == 0;
284 }
285 
ParsePartialFromFileDescriptor(int file_descriptor)286 bool MessageLite::ParsePartialFromFileDescriptor(int file_descriptor) {
287   io::FileInputStream input(file_descriptor);
288   return ParsePartialFromZeroCopyStream(&input) && input.GetErrno() == 0;
289 }
290 
ParseFromIstream(std::istream * input)291 bool MessageLite::ParseFromIstream(std::istream* input) {
292   io::IstreamInputStream zero_copy_input(input);
293   return ParseFromZeroCopyStream(&zero_copy_input) && input->eof();
294 }
295 
ParsePartialFromIstream(std::istream * input)296 bool MessageLite::ParsePartialFromIstream(std::istream* input) {
297   io::IstreamInputStream zero_copy_input(input);
298   return ParsePartialFromZeroCopyStream(&zero_copy_input) && input->eof();
299 }
300 
MergePartialFromBoundedZeroCopyStream(io::ZeroCopyInputStream * input,int size)301 bool MessageLite::MergePartialFromBoundedZeroCopyStream(
302     io::ZeroCopyInputStream* input, int size) {
303   return ParseFrom<kMergePartial>(internal::BoundedZCIS{input, size});
304 }
305 
MergeFromBoundedZeroCopyStream(io::ZeroCopyInputStream * input,int size)306 bool MessageLite::MergeFromBoundedZeroCopyStream(io::ZeroCopyInputStream* input,
307                                                  int size) {
308   return ParseFrom<kMerge>(internal::BoundedZCIS{input, size});
309 }
310 
ParseFromBoundedZeroCopyStream(io::ZeroCopyInputStream * input,int size)311 bool MessageLite::ParseFromBoundedZeroCopyStream(io::ZeroCopyInputStream* input,
312                                                  int size) {
313   return ParseFrom<kParse>(internal::BoundedZCIS{input, size});
314 }
315 
ParsePartialFromBoundedZeroCopyStream(io::ZeroCopyInputStream * input,int size)316 bool MessageLite::ParsePartialFromBoundedZeroCopyStream(
317     io::ZeroCopyInputStream* input, int size) {
318   return ParseFrom<kParsePartial>(internal::BoundedZCIS{input, size});
319 }
320 
ParseFromString(const std::string & data)321 bool MessageLite::ParseFromString(const std::string& data) {
322   return ParseFrom<kParse>(data);
323 }
324 
ParsePartialFromString(const std::string & data)325 bool MessageLite::ParsePartialFromString(const std::string& data) {
326   return ParseFrom<kParsePartial>(data);
327 }
328 
ParseFromArray(const void * data,int size)329 bool MessageLite::ParseFromArray(const void* data, int size) {
330   return ParseFrom<kParse>(as_string_view(data, size));
331 }
332 
ParsePartialFromArray(const void * data,int size)333 bool MessageLite::ParsePartialFromArray(const void* data, int size) {
334   return ParseFrom<kParsePartial>(as_string_view(data, size));
335 }
336 
MergeFromString(const std::string & data)337 bool MessageLite::MergeFromString(const std::string& data) {
338   return ParseFrom<kMerge>(data);
339 }
340 
341 
342 // ===================================================================
343 
SerializeWithCachedSizesToArray(uint8 * target) const344 uint8* MessageLite::SerializeWithCachedSizesToArray(uint8* target) const {
345   const internal::SerializationTable* table =
346       static_cast<const internal::SerializationTable*>(InternalGetTable());
347   auto deterministic =
348       io::CodedOutputStream::IsDefaultSerializationDeterministic();
349   if (table) {
350     return internal::TableSerializeToArray(*this, table, deterministic, target);
351   } else {
352     if (deterministic) {
353       // We only optimize this when using optimize_for = SPEED.  In other cases
354       // we just use the CodedOutputStream path.
355       int size = GetCachedSize();
356       io::ArrayOutputStream out(target, size);
357       io::CodedOutputStream coded_out(&out);
358       coded_out.SetSerializationDeterministic(true);
359       SerializeWithCachedSizes(&coded_out);
360       GOOGLE_CHECK(!coded_out.HadError());
361       return target + size;
362     } else {
363       return InternalSerializeWithCachedSizesToArray(target);
364     }
365   }
366 }
367 
SerializeToCodedStream(io::CodedOutputStream * output) const368 bool MessageLite::SerializeToCodedStream(io::CodedOutputStream* output) const {
369   GOOGLE_DCHECK(IsInitialized()) << InitializationErrorMessage("serialize", *this);
370   return SerializePartialToCodedStream(output);
371 }
372 
SerializePartialToCodedStream(io::CodedOutputStream * output) const373 bool MessageLite::SerializePartialToCodedStream(
374     io::CodedOutputStream* output) const {
375   const size_t size = ByteSizeLong();  // Force size to be cached.
376   if (size > INT_MAX) {
377     GOOGLE_LOG(ERROR) << GetTypeName()
378                << " exceeded maximum protobuf size of 2GB: " << size;
379     return false;
380   }
381 
382   if (!output->IsSerializationDeterministic()) {
383     uint8* buffer = output->GetDirectBufferForNBytesAndAdvance(size);
384     if (buffer != nullptr) {
385       uint8* end = InternalSerializeWithCachedSizesToArray(buffer);
386       if (end - buffer != size) {
387         ByteSizeConsistencyError(size, ByteSizeLong(), end - buffer, *this);
388       }
389       return true;
390     }
391   }
392   int original_byte_count = output->ByteCount();
393   SerializeWithCachedSizes(output);
394   if (output->HadError()) {
395     return false;
396   }
397   int final_byte_count = output->ByteCount();
398 
399   if (final_byte_count - original_byte_count != size) {
400     ByteSizeConsistencyError(size, ByteSizeLong(),
401                              final_byte_count - original_byte_count, *this);
402   }
403 
404   return true;
405 }
406 
SerializeToZeroCopyStream(io::ZeroCopyOutputStream * output) const407 bool MessageLite::SerializeToZeroCopyStream(
408     io::ZeroCopyOutputStream* output) const {
409   io::CodedOutputStream encoder(output);
410   return SerializeToCodedStream(&encoder);
411 }
412 
SerializePartialToZeroCopyStream(io::ZeroCopyOutputStream * output) const413 bool MessageLite::SerializePartialToZeroCopyStream(
414     io::ZeroCopyOutputStream* output) const {
415   io::CodedOutputStream encoder(output);
416   return SerializePartialToCodedStream(&encoder);
417 }
418 
SerializeToFileDescriptor(int file_descriptor) const419 bool MessageLite::SerializeToFileDescriptor(int file_descriptor) const {
420   io::FileOutputStream output(file_descriptor);
421   return SerializeToZeroCopyStream(&output) && output.Flush();
422 }
423 
SerializePartialToFileDescriptor(int file_descriptor) const424 bool MessageLite::SerializePartialToFileDescriptor(int file_descriptor) const {
425   io::FileOutputStream output(file_descriptor);
426   return SerializePartialToZeroCopyStream(&output) && output.Flush();
427 }
428 
SerializeToOstream(std::ostream * output) const429 bool MessageLite::SerializeToOstream(std::ostream* output) const {
430   {
431     io::OstreamOutputStream zero_copy_output(output);
432     if (!SerializeToZeroCopyStream(&zero_copy_output)) return false;
433   }
434   return output->good();
435 }
436 
SerializePartialToOstream(std::ostream * output) const437 bool MessageLite::SerializePartialToOstream(std::ostream* output) const {
438   io::OstreamOutputStream zero_copy_output(output);
439   return SerializePartialToZeroCopyStream(&zero_copy_output);
440 }
441 
AppendToString(std::string * output) const442 bool MessageLite::AppendToString(std::string* output) const {
443   GOOGLE_DCHECK(IsInitialized()) << InitializationErrorMessage("serialize", *this);
444   return AppendPartialToString(output);
445 }
446 
AppendPartialToString(std::string * output) const447 bool MessageLite::AppendPartialToString(std::string* output) const {
448   size_t old_size = output->size();
449   size_t byte_size = ByteSizeLong();
450   if (byte_size > INT_MAX) {
451     GOOGLE_LOG(ERROR) << GetTypeName()
452                << " exceeded maximum protobuf size of 2GB: " << byte_size;
453     return false;
454   }
455 
456   STLStringResizeUninitialized(output, old_size + byte_size);
457   uint8* start =
458       reinterpret_cast<uint8*>(io::mutable_string_data(output) + old_size);
459   uint8* end = SerializeWithCachedSizesToArray(start);
460   if (end - start != byte_size) {
461     ByteSizeConsistencyError(byte_size, ByteSizeLong(), end - start, *this);
462   }
463   return true;
464 }
465 
SerializeToString(std::string * output) const466 bool MessageLite::SerializeToString(std::string* output) const {
467   output->clear();
468   return AppendToString(output);
469 }
470 
SerializePartialToString(std::string * output) const471 bool MessageLite::SerializePartialToString(std::string* output) const {
472   output->clear();
473   return AppendPartialToString(output);
474 }
475 
SerializeToArray(void * data,int size) const476 bool MessageLite::SerializeToArray(void* data, int size) const {
477   GOOGLE_DCHECK(IsInitialized()) << InitializationErrorMessage("serialize", *this);
478   return SerializePartialToArray(data, size);
479 }
480 
SerializePartialToArray(void * data,int size) const481 bool MessageLite::SerializePartialToArray(void* data, int size) const {
482   const size_t byte_size = ByteSizeLong();
483   if (byte_size > INT_MAX) {
484     GOOGLE_LOG(ERROR) << GetTypeName()
485                << " exceeded maximum protobuf size of 2GB: " << byte_size;
486     return false;
487   }
488   if (size < byte_size) return false;
489   uint8* start = reinterpret_cast<uint8*>(data);
490   uint8* end = SerializeWithCachedSizesToArray(start);
491   if (end - start != byte_size) {
492     ByteSizeConsistencyError(byte_size, ByteSizeLong(), end - start, *this);
493   }
494   return true;
495 }
496 
SerializeAsString() const497 std::string MessageLite::SerializeAsString() const {
498   // If the compiler implements the (Named) Return Value Optimization,
499   // the local variable 'output' will not actually reside on the stack
500   // of this function, but will be overlaid with the object that the
501   // caller supplied for the return value to be constructed in.
502   std::string output;
503   if (!AppendToString(&output)) output.clear();
504   return output;
505 }
506 
SerializePartialAsString() const507 std::string MessageLite::SerializePartialAsString() const {
508   std::string output;
509   if (!AppendPartialToString(&output)) output.clear();
510   return output;
511 }
512 
SerializeWithCachedSizes(io::CodedOutputStream * output) const513 void MessageLite::SerializeWithCachedSizes(
514     io::CodedOutputStream* output) const {
515   GOOGLE_DCHECK(InternalGetTable());
516   internal::TableSerialize(
517       *this,
518       static_cast<const internal::SerializationTable*>(InternalGetTable()),
519       output);
520 }
521 
522 
523 // The table driven code optimizes the case that the CodedOutputStream buffer
524 // is large enough to serialize into it directly.
525 // If the proto is optimized for speed, this method will be overridden by
526 // generated code for maximum speed. If the proto is optimized for size or
527 // is lite, then we need to specialize this to avoid infinite recursion.
InternalSerializeWithCachedSizesToArray(uint8 * target) const528 uint8* MessageLite::InternalSerializeWithCachedSizesToArray(
529     uint8* target) const {
530   const internal::SerializationTable* table =
531       static_cast<const internal::SerializationTable*>(InternalGetTable());
532   if (table == NULL) {
533     // We only optimize this when using optimize_for = SPEED.  In other cases
534     // we just use the CodedOutputStream path.
535     int size = GetCachedSize();
536     io::ArrayOutputStream out(target, size);
537     io::CodedOutputStream coded_out(&out);
538     SerializeWithCachedSizes(&coded_out);
539     GOOGLE_CHECK(!coded_out.HadError());
540     return target + size;
541   } else {
542     return internal::TableSerializeToArray(*this, table, false, target);
543   }
544 }
545 
546 namespace internal {
547 
548 template <>
NewFromPrototype(const MessageLite * prototype,Arena * arena)549 MessageLite* GenericTypeHandler<MessageLite>::NewFromPrototype(
550     const MessageLite* prototype, Arena* arena) {
551   return prototype->New(arena);
552 }
553 template <>
Merge(const MessageLite & from,MessageLite * to)554 void GenericTypeHandler<MessageLite>::Merge(const MessageLite& from,
555                                             MessageLite* to) {
556   to->CheckTypeAndMergeFrom(from);
557 }
558 template <>
Merge(const std::string & from,std::string * to)559 void GenericTypeHandler<std::string>::Merge(const std::string& from,
560                                             std::string* to) {
561   *to = from;
562 }
563 
564 }  // namespace internal
565 
566 }  // namespace protobuf
567 }  // namespace google
568