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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 // Defines MessageLite, the abstract interface implemented by all (lite
37 // and non-lite) protocol message objects.
38 
39 #ifndef GOOGLE_PROTOBUF_MESSAGE_LITE_H__
40 #define GOOGLE_PROTOBUF_MESSAGE_LITE_H__
41 
42 #include <climits>
43 #include <string>
44 
45 #include <google/protobuf/stubs/common.h>
46 #include <google/protobuf/stubs/logging.h>
47 #include <google/protobuf/io/coded_stream.h>
48 #include <google/protobuf/arena.h>
49 #include <google/protobuf/metadata_lite.h>
50 #include <google/protobuf/stubs/once.h>
51 #include <google/protobuf/port.h>
52 #include <google/protobuf/stubs/strutil.h>
53 
54 
55 #include <google/protobuf/port_def.inc>
56 
57 #ifdef SWIG
58 #error "You cannot SWIG proto headers"
59 #endif
60 
61 namespace google {
62 namespace protobuf {
63 
64 template <typename T>
65 class RepeatedPtrField;
66 
67 namespace io {
68 
69 class CodedInputStream;
70 class CodedOutputStream;
71 class ZeroCopyInputStream;
72 class ZeroCopyOutputStream;
73 
74 }  // namespace io
75 namespace internal {
76 
77 // Tag type used to invoke the constinit constructor overload of some classes.
78 // Such constructors are internal implementation details of the library.
79 struct ConstantInitialized {
80   explicit ConstantInitialized() = default;
81 };
82 
83 // See parse_context.h for explanation
84 class ParseContext;
85 
86 class RepeatedPtrFieldBase;
87 class WireFormatLite;
88 class WeakFieldMap;
89 
90 // We compute sizes as size_t but cache them as int.  This function converts a
91 // computed size to a cached size.  Since we don't proceed with serialization
92 // if the total size was > INT_MAX, it is not important what this function
93 // returns for inputs > INT_MAX.  However this case should not error or
94 // GOOGLE_CHECK-fail, because the full size_t resolution is still returned from
95 // ByteSizeLong() and checked against INT_MAX; we can catch the overflow
96 // there.
ToCachedSize(size_t size)97 inline int ToCachedSize(size_t size) { return static_cast<int>(size); }
98 
99 // We mainly calculate sizes in terms of size_t, but some functions that
100 // compute sizes return "int".  These int sizes are expected to always be
101 // positive. This function is more efficient than casting an int to size_t
102 // directly on 64-bit platforms because it avoids making the compiler emit a
103 // sign extending instruction, which we don't want and don't want to pay for.
FromIntSize(int size)104 inline size_t FromIntSize(int size) {
105   // Convert to unsigned before widening so sign extension is not necessary.
106   return static_cast<unsigned int>(size);
107 }
108 
109 // For cases where a legacy function returns an integer size.  We GOOGLE_DCHECK()
110 // that the conversion will fit within an integer; if this is false then we
111 // are losing information.
ToIntSize(size_t size)112 inline int ToIntSize(size_t size) {
113   GOOGLE_DCHECK_LE(size, static_cast<size_t>(INT_MAX));
114   return static_cast<int>(size);
115 }
116 
117 // This type wraps a variable whose constructor and destructor are explicitly
118 // called. It is particularly useful for a global variable, without its
119 // constructor and destructor run on start and end of the program lifetime.
120 // This circumvents the initial construction order fiasco, while keeping
121 // the address of the empty string a compile time constant.
122 //
123 // Pay special attention to the initialization state of the object.
124 // 1. The object is "uninitialized" to begin with.
125 // 2. Call Construct() or DefaultConstruct() only if the object is
126 //    uninitialized. After the call, the object becomes "initialized".
127 // 3. Call get() and get_mutable() only if the object is initialized.
128 // 4. Call Destruct() only if the object is initialized.
129 //    After the call, the object becomes uninitialized.
130 template <typename T>
131 class ExplicitlyConstructed {
132  public:
DefaultConstruct()133   void DefaultConstruct() { new (&union_) T(); }
134 
135   template <typename... Args>
Construct(Args &&...args)136   void Construct(Args&&... args) {
137     new (&union_) T(std::forward<Args>(args)...);
138   }
139 
Destruct()140   void Destruct() { get_mutable()->~T(); }
141 
get()142   constexpr const T& get() const { return reinterpret_cast<const T&>(union_); }
get_mutable()143   T* get_mutable() { return reinterpret_cast<T*>(&union_); }
144 
145  private:
146   // Prefer c++14 aligned_storage, but for compatibility this will do.
147   union AlignedUnion {
148     char space[sizeof(T)];
149     int64 align_to_int64;
150     void* align_to_ptr;
151   } union_;
152 };
153 
154 PROTOBUF_DISABLE_MSVC_UNION_WARNING
155 // We need a publicly accessible `value` object to allow constexpr
156 // support in C++11.
157 // A constexpr accessor does not work portably.
158 union EmptyString {
EmptyString()159   constexpr EmptyString() : dummy{} {}
~EmptyString()160   ~EmptyString() {}
161 
162   // We need a dummy object for constant initialization.
163   std::false_type dummy;
164   std::string value;
165 };
166 PROTOBUF_ENABLE_MSVC_UNION_WARNING
167 
168 // Default empty string object. Don't use this directly. Instead, call
169 // GetEmptyString() to get the reference.
170 PROTOBUF_EXPORT extern EmptyString fixed_address_empty_string;
171 
172 
GetEmptyStringAlreadyInited()173 PROTOBUF_EXPORT constexpr const std::string& GetEmptyStringAlreadyInited() {
174   return fixed_address_empty_string.value;
175 }
176 
177 PROTOBUF_EXPORT size_t StringSpaceUsedExcludingSelfLong(const std::string& str);
178 
179 }  // namespace internal
180 
181 // Interface to light weight protocol messages.
182 //
183 // This interface is implemented by all protocol message objects.  Non-lite
184 // messages additionally implement the Message interface, which is a
185 // subclass of MessageLite.  Use MessageLite instead when you only need
186 // the subset of features which it supports -- namely, nothing that uses
187 // descriptors or reflection.  You can instruct the protocol compiler
188 // to generate classes which implement only MessageLite, not the full
189 // Message interface, by adding the following line to the .proto file:
190 //
191 //   option optimize_for = LITE_RUNTIME;
192 //
193 // This is particularly useful on resource-constrained systems where
194 // the full protocol buffers runtime library is too big.
195 //
196 // Note that on non-constrained systems (e.g. servers) when you need
197 // to link in lots of protocol definitions, a better way to reduce
198 // total code footprint is to use optimize_for = CODE_SIZE.  This
199 // will make the generated code smaller while still supporting all the
200 // same features (at the expense of speed).  optimize_for = LITE_RUNTIME
201 // is best when you only have a small number of message types linked
202 // into your binary, in which case the size of the protocol buffers
203 // runtime itself is the biggest problem.
204 //
205 // Users must not derive from this class. Only the protocol compiler and
206 // the internal library are allowed to create subclasses.
207 class PROTOBUF_EXPORT MessageLite {
208  public:
209   constexpr MessageLite() = default;
210   virtual ~MessageLite() = default;
211 
212   // Basic Operations ------------------------------------------------
213 
214   // Get the name of this message type, e.g. "foo.bar.BazProto".
215   virtual std::string GetTypeName() const = 0;
216 
217   // Construct a new instance of the same type.  Ownership is passed to the
218   // caller.
219   virtual MessageLite* New() const = 0;
220 
221   // Construct a new instance on the arena. Ownership is passed to the caller
222   // if arena is a NULL. Default implementation for backwards compatibility.
223   virtual MessageLite* New(Arena* arena) const;
224 
225   // Get the arena, if any, associated with this message. Virtual method
226   // required for generic operations but most arena-related operations should
227   // use the GetArena() generated-code method. Default implementation
228   // to reduce code size by avoiding the need for per-type implementations
229   // when types do not implement arena support.
GetArena()230   Arena* GetArena() const { return _internal_metadata_.arena(); }
231 
232   // Get a pointer that may be equal to this message's arena, or may not be.
233   // If the value returned by this method is equal to some arena pointer, then
234   // this message is on that arena; however, if this message is on some arena,
235   // this method may or may not return that arena's pointer. As a tradeoff,
236   // this method may be more efficient than GetArena(). The intent is to allow
237   // underlying representations that use e.g. tagged pointers to sometimes
238   // store the arena pointer directly, and sometimes in a more indirect way,
239   // and allow a fastpath comparison against the arena pointer when it's easy
240   // to obtain.
GetMaybeArenaPointer()241   void* GetMaybeArenaPointer() const {
242     return _internal_metadata_.raw_arena_ptr();
243   }
244 
245   // Clear all fields of the message and set them to their default values.
246   // Clear() avoids freeing memory, assuming that any memory allocated
247   // to hold parts of the message will be needed again to hold the next
248   // message.  If you actually want to free the memory used by a Message,
249   // you must delete it.
250   virtual void Clear() = 0;
251 
252   // Quickly check if all required fields have values set.
253   virtual bool IsInitialized() const = 0;
254 
255   // This is not implemented for Lite messages -- it just returns "(cannot
256   // determine missing fields for lite message)".  However, it is implemented
257   // for full messages.  See message.h.
258   virtual std::string InitializationErrorString() const;
259 
260   // If |other| is the exact same class as this, calls MergeFrom(). Otherwise,
261   // results are undefined (probably crash).
262   virtual void CheckTypeAndMergeFrom(const MessageLite& other) = 0;
263 
264   // These methods return a human-readable summary of the message. Note that
265   // since the MessageLite interface does not support reflection, there is very
266   // little information that these methods can provide. They are shadowed by
267   // methods of the same name on the Message interface which provide much more
268   // information. The methods here are intended primarily to facilitate code
269   // reuse for logic that needs to interoperate with both full and lite protos.
270   //
271   // The format of the returned string is subject to change, so please do not
272   // assume it will remain stable over time.
273   std::string DebugString() const;
ShortDebugString()274   std::string ShortDebugString() const { return DebugString(); }
275   // MessageLite::DebugString is already Utf8 Safe. This is to add compatibility
276   // with Message.
Utf8DebugString()277   std::string Utf8DebugString() const { return DebugString(); }
278 
279   // Parsing ---------------------------------------------------------
280   // Methods for parsing in protocol buffer format.  Most of these are
281   // just simple wrappers around MergeFromCodedStream().  Clear() will be
282   // called before merging the input.
283 
284   // Fill the message with a protocol buffer parsed from the given input
285   // stream. Returns false on a read error or if the input is in the wrong
286   // format.  A successful return does not indicate the entire input is
287   // consumed, ensure you call ConsumedEntireMessage() to check that if
288   // applicable.
289   PROTOBUF_ATTRIBUTE_REINITIALIZES bool ParseFromCodedStream(
290       io::CodedInputStream* input);
291   // Like ParseFromCodedStream(), but accepts messages that are missing
292   // required fields.
293   PROTOBUF_ATTRIBUTE_REINITIALIZES bool ParsePartialFromCodedStream(
294       io::CodedInputStream* input);
295   // Read a protocol buffer from the given zero-copy input stream.  If
296   // successful, the entire input will be consumed.
297   PROTOBUF_ATTRIBUTE_REINITIALIZES bool ParseFromZeroCopyStream(
298       io::ZeroCopyInputStream* input);
299   // Like ParseFromZeroCopyStream(), but accepts messages that are missing
300   // required fields.
301   PROTOBUF_ATTRIBUTE_REINITIALIZES bool ParsePartialFromZeroCopyStream(
302       io::ZeroCopyInputStream* input);
303   // Parse a protocol buffer from a file descriptor.  If successful, the entire
304   // input will be consumed.
305   PROTOBUF_ATTRIBUTE_REINITIALIZES bool ParseFromFileDescriptor(
306       int file_descriptor);
307   // Like ParseFromFileDescriptor(), but accepts messages that are missing
308   // required fields.
309   PROTOBUF_ATTRIBUTE_REINITIALIZES bool ParsePartialFromFileDescriptor(
310       int file_descriptor);
311   // Parse a protocol buffer from a C++ istream.  If successful, the entire
312   // input will be consumed.
313   PROTOBUF_ATTRIBUTE_REINITIALIZES bool ParseFromIstream(std::istream* input);
314   // Like ParseFromIstream(), but accepts messages that are missing
315   // required fields.
316   PROTOBUF_ATTRIBUTE_REINITIALIZES bool ParsePartialFromIstream(
317       std::istream* input);
318   // Read a protocol buffer from the given zero-copy input stream, expecting
319   // the message to be exactly "size" bytes long.  If successful, exactly
320   // this many bytes will have been consumed from the input.
321   bool MergePartialFromBoundedZeroCopyStream(io::ZeroCopyInputStream* input,
322                                              int size);
323   // Like ParseFromBoundedZeroCopyStream(), but accepts messages that are
324   // missing required fields.
325   bool MergeFromBoundedZeroCopyStream(io::ZeroCopyInputStream* input, int size);
326   PROTOBUF_ATTRIBUTE_REINITIALIZES bool ParseFromBoundedZeroCopyStream(
327       io::ZeroCopyInputStream* input, int size);
328   // Like ParseFromBoundedZeroCopyStream(), but accepts messages that are
329   // missing required fields.
330   PROTOBUF_ATTRIBUTE_REINITIALIZES bool ParsePartialFromBoundedZeroCopyStream(
331       io::ZeroCopyInputStream* input, int size);
332   // Parses a protocol buffer contained in a string. Returns true on success.
333   // This function takes a string in the (non-human-readable) binary wire
334   // format, matching the encoding output by MessageLite::SerializeToString().
335   // If you'd like to convert a human-readable string into a protocol buffer
336   // object, see google::protobuf::TextFormat::ParseFromString().
337   PROTOBUF_ATTRIBUTE_REINITIALIZES bool ParseFromString(ConstStringParam data);
338   // Like ParseFromString(), but accepts messages that are missing
339   // required fields.
340   PROTOBUF_ATTRIBUTE_REINITIALIZES bool ParsePartialFromString(
341       ConstStringParam data);
342   // Parse a protocol buffer contained in an array of bytes.
343   PROTOBUF_ATTRIBUTE_REINITIALIZES bool ParseFromArray(const void* data,
344                                                        int size);
345   // Like ParseFromArray(), but accepts messages that are missing
346   // required fields.
347   PROTOBUF_ATTRIBUTE_REINITIALIZES bool ParsePartialFromArray(const void* data,
348                                                               int size);
349 
350 
351   // Reads a protocol buffer from the stream and merges it into this
352   // Message.  Singular fields read from the what is
353   // already in the Message and repeated fields are appended to those
354   // already present.
355   //
356   // It is the responsibility of the caller to call input->LastTagWas()
357   // (for groups) or input->ConsumedEntireMessage() (for non-groups) after
358   // this returns to verify that the message's end was delimited correctly.
359   //
360   // ParseFromCodedStream() is implemented as Clear() followed by
361   // MergeFromCodedStream().
362   bool MergeFromCodedStream(io::CodedInputStream* input);
363 
364   // Like MergeFromCodedStream(), but succeeds even if required fields are
365   // missing in the input.
366   //
367   // MergeFromCodedStream() is just implemented as MergePartialFromCodedStream()
368   // followed by IsInitialized().
369   bool MergePartialFromCodedStream(io::CodedInputStream* input);
370 
371   // Merge a protocol buffer contained in a string.
372   bool MergeFromString(ConstStringParam data);
373 
374 
375   // Serialization ---------------------------------------------------
376   // Methods for serializing in protocol buffer format.  Most of these
377   // are just simple wrappers around ByteSize() and SerializeWithCachedSizes().
378 
379   // Write a protocol buffer of this message to the given output.  Returns
380   // false on a write error.  If the message is missing required fields,
381   // this may GOOGLE_CHECK-fail.
382   bool SerializeToCodedStream(io::CodedOutputStream* output) const;
383   // Like SerializeToCodedStream(), but allows missing required fields.
384   bool SerializePartialToCodedStream(io::CodedOutputStream* output) const;
385   // Write the message to the given zero-copy output stream.  All required
386   // fields must be set.
387   bool SerializeToZeroCopyStream(io::ZeroCopyOutputStream* output) const;
388   // Like SerializeToZeroCopyStream(), but allows missing required fields.
389   bool SerializePartialToZeroCopyStream(io::ZeroCopyOutputStream* output) const;
390   // Serialize the message and store it in the given string.  All required
391   // fields must be set.
392   bool SerializeToString(std::string* output) const;
393   // Like SerializeToString(), but allows missing required fields.
394   bool SerializePartialToString(std::string* output) const;
395   // Serialize the message and store it in the given byte array.  All required
396   // fields must be set.
397   bool SerializeToArray(void* data, int size) const;
398   // Like SerializeToArray(), but allows missing required fields.
399   bool SerializePartialToArray(void* data, int size) const;
400 
401   // Make a string encoding the message. Is equivalent to calling
402   // SerializeToString() on a string and using that.  Returns the empty
403   // string if SerializeToString() would have returned an error.
404   // Note: If you intend to generate many such strings, you may
405   // reduce heap fragmentation by instead re-using the same string
406   // object with calls to SerializeToString().
407   std::string SerializeAsString() const;
408   // Like SerializeAsString(), but allows missing required fields.
409   std::string SerializePartialAsString() const;
410 
411   // Serialize the message and write it to the given file descriptor.  All
412   // required fields must be set.
413   bool SerializeToFileDescriptor(int file_descriptor) const;
414   // Like SerializeToFileDescriptor(), but allows missing required fields.
415   bool SerializePartialToFileDescriptor(int file_descriptor) const;
416   // Serialize the message and write it to the given C++ ostream.  All
417   // required fields must be set.
418   bool SerializeToOstream(std::ostream* output) const;
419   // Like SerializeToOstream(), but allows missing required fields.
420   bool SerializePartialToOstream(std::ostream* output) const;
421 
422   // Like SerializeToString(), but appends to the data to the string's
423   // existing contents.  All required fields must be set.
424   bool AppendToString(std::string* output) const;
425   // Like AppendToString(), but allows missing required fields.
426   bool AppendPartialToString(std::string* output) const;
427 
428 
429   // Computes the serialized size of the message.  This recursively calls
430   // ByteSizeLong() on all embedded messages.
431   //
432   // ByteSizeLong() is generally linear in the number of fields defined for the
433   // proto.
434   virtual size_t ByteSizeLong() const = 0;
435 
436   // Legacy ByteSize() API.
437   PROTOBUF_DEPRECATED_MSG("Please use ByteSizeLong() instead")
ByteSize()438   int ByteSize() const { return internal::ToIntSize(ByteSizeLong()); }
439 
440   // Serializes the message without recomputing the size.  The message must not
441   // have changed since the last call to ByteSize(), and the value returned by
442   // ByteSize must be non-negative.  Otherwise the results are undefined.
SerializeWithCachedSizes(io::CodedOutputStream * output)443   void SerializeWithCachedSizes(io::CodedOutputStream* output) const {
444     output->SetCur(_InternalSerialize(output->Cur(), output->EpsCopy()));
445   }
446 
447   // Functions below here are not part of the public interface.  It isn't
448   // enforced, but they should be treated as private, and will be private
449   // at some future time.  Unfortunately the implementation of the "friend"
450   // keyword in GCC is broken at the moment, but we expect it will be fixed.
451 
452   // Like SerializeWithCachedSizes, but writes directly to *target, returning
453   // a pointer to the byte immediately after the last byte written.  "target"
454   // must point at a byte array of at least ByteSize() bytes.  Whether to use
455   // deterministic serialization, e.g., maps in sorted order, is determined by
456   // CodedOutputStream::IsDefaultSerializationDeterministic().
457   uint8* SerializeWithCachedSizesToArray(uint8* target) const;
458 
459   // Returns the result of the last call to ByteSize().  An embedded message's
460   // size is needed both to serialize it (because embedded messages are
461   // length-delimited) and to compute the outer message's size.  Caching
462   // the size avoids computing it multiple times.
463   //
464   // ByteSize() does not automatically use the cached size when available
465   // because this would require invalidating it every time the message was
466   // modified, which would be too hard and expensive.  (E.g. if a deeply-nested
467   // sub-message is changed, all of its parents' cached sizes would need to be
468   // invalidated, which is too much work for an otherwise inlined setter
469   // method.)
470   virtual int GetCachedSize() const = 0;
471 
_InternalParse(const char *,internal::ParseContext *)472   virtual const char* _InternalParse(const char* /*ptr*/,
473                                      internal::ParseContext* /*ctx*/) {
474     return nullptr;
475   }
476 
477  protected:
478   template <typename T>
CreateMaybeMessage(Arena * arena)479   static T* CreateMaybeMessage(Arena* arena) {
480     return Arena::CreateMaybeMessage<T>(arena);
481   }
482 
MessageLite(Arena * arena)483   inline explicit MessageLite(Arena* arena) : _internal_metadata_(arena) {}
484 
485   internal::InternalMetadata _internal_metadata_;
486 
487  public:
488   enum ParseFlags {
489     kMerge = 0,
490     kParse = 1,
491     kMergePartial = 2,
492     kParsePartial = 3,
493     kMergeWithAliasing = 4,
494     kParseWithAliasing = 5,
495     kMergePartialWithAliasing = 6,
496     kParsePartialWithAliasing = 7
497   };
498 
499   template <ParseFlags flags, typename T>
500   bool ParseFrom(const T& input);
501 
502   // Fast path when conditions match (ie. non-deterministic)
503   //  uint8* _InternalSerialize(uint8* ptr) const;
504   virtual uint8* _InternalSerialize(uint8* ptr,
505                                     io::EpsCopyOutputStream* stream) const = 0;
506 
507   // Identical to IsInitialized() except that it logs an error message.
IsInitializedWithErrors()508   bool IsInitializedWithErrors() const {
509     if (IsInitialized()) return true;
510     LogInitializationErrorMessage();
511     return false;
512   }
513 
514  private:
515   // TODO(gerbens) make this a pure abstract function
InternalGetTable()516   virtual const void* InternalGetTable() const { return NULL; }
517 
518   friend class internal::WireFormatLite;
519   friend class Message;
520   friend class internal::WeakFieldMap;
521 
522   void LogInitializationErrorMessage() const;
523 
524   bool MergeFromImpl(io::CodedInputStream* input, ParseFlags parse_flags);
525 
526   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(MessageLite);
527 };
528 
529 namespace internal {
530 
531 template <bool alias>
532 bool MergeFromImpl(StringPiece input, MessageLite* msg,
533                    MessageLite::ParseFlags parse_flags);
534 extern template bool MergeFromImpl<false>(StringPiece input,
535                                           MessageLite* msg,
536                                           MessageLite::ParseFlags parse_flags);
537 extern template bool MergeFromImpl<true>(StringPiece input,
538                                          MessageLite* msg,
539                                          MessageLite::ParseFlags parse_flags);
540 
541 template <bool alias>
542 bool MergeFromImpl(io::ZeroCopyInputStream* input, MessageLite* msg,
543                    MessageLite::ParseFlags parse_flags);
544 extern template bool MergeFromImpl<false>(io::ZeroCopyInputStream* input,
545                                           MessageLite* msg,
546                                           MessageLite::ParseFlags parse_flags);
547 extern template bool MergeFromImpl<true>(io::ZeroCopyInputStream* input,
548                                          MessageLite* msg,
549                                          MessageLite::ParseFlags parse_flags);
550 
551 struct BoundedZCIS {
552   io::ZeroCopyInputStream* zcis;
553   int limit;
554 };
555 
556 template <bool alias>
557 bool MergeFromImpl(BoundedZCIS input, MessageLite* msg,
558                    MessageLite::ParseFlags parse_flags);
559 extern template bool MergeFromImpl<false>(BoundedZCIS input, MessageLite* msg,
560                                           MessageLite::ParseFlags parse_flags);
561 extern template bool MergeFromImpl<true>(BoundedZCIS input, MessageLite* msg,
562                                          MessageLite::ParseFlags parse_flags);
563 
564 template <typename T>
565 struct SourceWrapper;
566 
567 template <bool alias, typename T>
MergeFromImpl(const SourceWrapper<T> & input,MessageLite * msg,MessageLite::ParseFlags parse_flags)568 bool MergeFromImpl(const SourceWrapper<T>& input, MessageLite* msg,
569                    MessageLite::ParseFlags parse_flags) {
570   return input.template MergeInto<alias>(msg, parse_flags);
571 }
572 
573 }  // namespace internal
574 
575 template <MessageLite::ParseFlags flags, typename T>
ParseFrom(const T & input)576 bool MessageLite::ParseFrom(const T& input) {
577   if (flags & kParse) Clear();
578   constexpr bool alias = (flags & kMergeWithAliasing) != 0;
579   return internal::MergeFromImpl<alias>(input, this, flags);
580 }
581 
582 // ===================================================================
583 // Shutdown support.
584 
585 
586 // Shut down the entire protocol buffers library, deleting all static-duration
587 // objects allocated by the library or by generated .pb.cc files.
588 //
589 // There are two reasons you might want to call this:
590 // * You use a draconian definition of "memory leak" in which you expect
591 //   every single malloc() to have a corresponding free(), even for objects
592 //   which live until program exit.
593 // * You are writing a dynamically-loaded library which needs to clean up
594 //   after itself when the library is unloaded.
595 //
596 // It is safe to call this multiple times.  However, it is not safe to use
597 // any other part of the protocol buffers library after
598 // ShutdownProtobufLibrary() has been called. Furthermore this call is not
599 // thread safe, user needs to synchronize multiple calls.
600 PROTOBUF_EXPORT void ShutdownProtobufLibrary();
601 
602 namespace internal {
603 
604 // Register a function to be called when ShutdownProtocolBuffers() is called.
605 PROTOBUF_EXPORT void OnShutdown(void (*func)());
606 // Run an arbitrary function on an arg
607 PROTOBUF_EXPORT void OnShutdownRun(void (*f)(const void*), const void* arg);
608 
609 template <typename T>
OnShutdownDelete(T * p)610 T* OnShutdownDelete(T* p) {
611   OnShutdownRun([](const void* pp) { delete static_cast<const T*>(pp); }, p);
612   return p;
613 }
614 
615 }  // namespace internal
616 }  // namespace protobuf
617 }  // namespace google
618 
619 #include <google/protobuf/port_undef.inc>
620 
621 #endif  // GOOGLE_PROTOBUF_MESSAGE_LITE_H__
622