Pull new version of protobuf sources.

third_party/protobuf/src/google/protobuf/unknown_field_set.cc

Index: third_party/protobuf/src/google/protobuf/unknown_field_set.cc
diff --git a/third_party/protobuf/src/google/protobuf/unknown_field_set.cc b/third_party/protobuf/src/google/protobuf/unknown_field_set.cc
index b6aaa187b7aa23ac89159143ae1610b916f92f42..7e04a0e6bf9310878abdc7b82c644d8b0904d062 100644
--- a/third_party/protobuf/src/google/protobuf/unknown_field_set.cc
+++ b/third_party/protobuf/src/google/protobuf/unknown_field_set.cc
@@ -1,6 +1,6 @@
 // Protocol Buffers - Google's data interchange format
 // Copyright 2008 Google Inc.  All rights reserved.
-// http://code.google.com/p/protobuf/
+// https://developers.google.com/protocol-buffers/
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
@@ -35,33 +35,43 @@
 #include <google/protobuf/unknown_field_set.h>
 
 #include <google/protobuf/stubs/common.h>
+#include <google/protobuf/stubs/once.h>
 #include <google/protobuf/io/coded_stream.h>
 #include <google/protobuf/io/zero_copy_stream.h>
 #include <google/protobuf/io/zero_copy_stream_impl_lite.h>
+#include <google/protobuf/generated_message_util.h>
 #include <google/protobuf/wire_format_lite.h>
 #include <google/protobuf/stubs/stl_util.h>
 
 namespace google {
 namespace protobuf {
 
-namespace internal {
+namespace {
+// This global instance is returned by unknown_fields() on any message class
+// when the object has no unknown fields. This is necessary because we now
+// instantiate the UnknownFieldSet dynamically only when required.
+UnknownFieldSet* default_unknown_field_set_instance_ = NULL;
 
-int StringSpaceUsedExcludingSelf(const string& str) {
-  const void* start = &str;
-  const void* end = &str + 1;
+void DeleteDefaultUnknownFieldSet() {
+  delete default_unknown_field_set_instance_;
+}
 
-  if (start <= str.data() && str.data() <= end) {
-    // The string's data is stored inside the string object itself.
-    return 0;
-  } else {
-    return str.capacity();
-  }
+void InitDefaultUnknownFieldSet() {
+  default_unknown_field_set_instance_ = new UnknownFieldSet();
+  internal::OnShutdown(&DeleteDefaultUnknownFieldSet);
+}
+
+GOOGLE_PROTOBUF_DECLARE_ONCE(default_unknown_field_set_once_init_);
 }
 
+const UnknownFieldSet* UnknownFieldSet::default_instance() {
+  ::google::protobuf::GoogleOnceInit(&default_unknown_field_set_once_init_,
+                 &InitDefaultUnknownFieldSet);
+  return default_unknown_field_set_instance_;
 }
 
 UnknownFieldSet::UnknownFieldSet()
-  : fields_(NULL) {}
+    : fields_(NULL) {}
 
 UnknownFieldSet::~UnknownFieldSet() {
   Clear();
@@ -69,31 +79,63 @@ UnknownFieldSet::~UnknownFieldSet() {
 }
 
 void UnknownFieldSet::ClearFallback() {
-  GOOGLE_DCHECK(fields_ != NULL);
-  for (int i = 0; i < fields_->size(); i++) {
-    (*fields_)[i].Delete();
+  if (fields_ != NULL) {
+    for (int i = 0; i < fields_->size(); i++) {
+      (*fields_)[i].Delete();
+    }
+    delete fields_;
+    fields_ = NULL;
   }
-  fields_->clear();
 }
 
 void UnknownFieldSet::ClearAndFreeMemory() {
   if (fields_ != NULL) {
     Clear();
-    delete fields_;
-    fields_ = NULL;
+  }
+}
+
+void UnknownFieldSet::InternalMergeFrom(const UnknownFieldSet& other) {
+  int other_field_count = other.field_count();
+  if (other_field_count > 0) {
+    fields_ = new vector<UnknownField>();
+    for (int i = 0; i < other_field_count; i++) {
+      fields_->push_back((*other.fields_)[i]);
+      fields_->back().DeepCopy((*other.fields_)[i]);
+    }
   }
 }
 
 void UnknownFieldSet::MergeFrom(const UnknownFieldSet& other) {
-  for (int i = 0; i < other.field_count(); i++) {
-    AddField(other.field(i));
+  int other_field_count = other.field_count();
+  if (other_field_count > 0) {
+    if (fields_ == NULL) fields_ = new vector<UnknownField>();
+    for (int i = 0; i < other_field_count; i++) {
+      fields_->push_back((*other.fields_)[i]);
+      fields_->back().DeepCopy((*other.fields_)[i]);
+    }
+  }
+}
+
+// A specialized MergeFrom for performance when we are merging from an UFS that
+// is temporary and can be destroyed in the process.
+void UnknownFieldSet::MergeFromAndDestroy(UnknownFieldSet* other) {
+  int other_field_count = other->field_count();
+  if (other_field_count > 0) {
+    if (fields_ == NULL) fields_ = new vector<UnknownField>();
+    for (int i = 0; i < other_field_count; i++) {
+      fields_->push_back((*other->fields_)[i]);
+      (*other->fields_)[i].Reset();
+    }
   }
+  delete other->fields_;
+  other->fields_ = NULL;
 }
 
 int UnknownFieldSet::SpaceUsedExcludingSelf() const {
   if (fields_ == NULL) return 0;
 
   int total_size = sizeof(*fields_) + sizeof(UnknownField) * fields_->size();
+
   for (int i = 0; i < fields_->size(); i++) {
     const UnknownField& field = (*fields_)[i];
     switch (field.type()) {
@@ -117,61 +159,60 @@ int UnknownFieldSet::SpaceUsed() const {
 }
 
 void UnknownFieldSet::AddVarint(int number, uint64 value) {
-  if (fields_ == NULL) fields_ = new vector<UnknownField>;
   UnknownField field;
   field.number_ = number;
-  field.type_ = UnknownField::TYPE_VARINT;
+  field.SetType(UnknownField::TYPE_VARINT);
   field.varint_ = value;
+  if (fields_ == NULL) fields_ = new vector<UnknownField>();
   fields_->push_back(field);
 }
 
 void UnknownFieldSet::AddFixed32(int number, uint32 value) {
-  if (fields_ == NULL) fields_ = new vector<UnknownField>;
   UnknownField field;
   field.number_ = number;
-  field.type_ = UnknownField::TYPE_FIXED32;
+  field.SetType(UnknownField::TYPE_FIXED32);
   field.fixed32_ = value;
+  if (fields_ == NULL) fields_ = new vector<UnknownField>();
   fields_->push_back(field);
 }
 
 void UnknownFieldSet::AddFixed64(int number, uint64 value) {
-  if (fields_ == NULL) fields_ = new vector<UnknownField>;
   UnknownField field;
   field.number_ = number;
-  field.type_ = UnknownField::TYPE_FIXED64;
+  field.SetType(UnknownField::TYPE_FIXED64);
   field.fixed64_ = value;
+  if (fields_ == NULL) fields_ = new vector<UnknownField>();
   fields_->push_back(field);
 }
 
 string* UnknownFieldSet::AddLengthDelimited(int number) {
-  if (fields_ == NULL) fields_ = new vector<UnknownField>;
   UnknownField field;
   field.number_ = number;
-  field.type_ = UnknownField::TYPE_LENGTH_DELIMITED;
+  field.SetType(UnknownField::TYPE_LENGTH_DELIMITED);
   field.length_delimited_.string_value_ = new string;
+  if (fields_ == NULL) fields_ = new vector<UnknownField>();
   fields_->push_back(field);
   return field.length_delimited_.string_value_;
 }
 
 
 UnknownFieldSet* UnknownFieldSet::AddGroup(int number) {
-  if (fields_ == NULL) fields_ = new vector<UnknownField>;
   UnknownField field;
   field.number_ = number;
-  field.type_ = UnknownField::TYPE_GROUP;
+  field.SetType(UnknownField::TYPE_GROUP);
   field.group_ = new UnknownFieldSet;
+  if (fields_ == NULL) fields_ = new vector<UnknownField>();
   fields_->push_back(field);
   return field.group_;
 }
 
 void UnknownFieldSet::AddField(const UnknownField& field) {
-  if (fields_ == NULL) fields_ = new vector<UnknownField>;
+  if (fields_ == NULL) fields_ = new vector<UnknownField>();
   fields_->push_back(field);
-  fields_->back().DeepCopy();
+  fields_->back().DeepCopy(field);
 }
 
 void UnknownFieldSet::DeleteSubrange(int start, int num) {
-  GOOGLE_DCHECK(fields_ != NULL);
   // Delete the specified fields.
   for (int i = 0; i < num; ++i) {
     (*fields_)[i + start].Delete();
@@ -184,6 +225,11 @@ void UnknownFieldSet::DeleteSubrange(int start, int num) {
   for (int i = 0; i < num; ++i) {
     fields_->pop_back();
   }
+  if (fields_ && fields_->size() == 0) {
+    // maintain invariant: never hold fields_ if empty.
+    delete fields_;
+    fields_ = NULL;
+  }
 }
 
 void UnknownFieldSet::DeleteByNumber(int number) {
@@ -201,14 +247,18 @@ void UnknownFieldSet::DeleteByNumber(int number) {
     }
   }
   fields_->resize(left);
+  if (left == 0) {
+    // maintain invariant: never hold fields_ if empty.
+    delete fields_;
+    fields_ = NULL;
+  }
 }
 
 bool UnknownFieldSet::MergeFromCodedStream(io::CodedInputStream* input) {
-
   UnknownFieldSet other;
   if (internal::WireFormatLite::SkipMessage(input, &other) &&
       input->ConsumedEntireMessage()) {
-    MergeFrom(other);
+    MergeFromAndDestroy(&other);
     return true;
   } else {
     return false;
@@ -222,8 +272,8 @@ bool UnknownFieldSet::ParseFromCodedStream(io::CodedInputStream* input) {
 
 bool UnknownFieldSet::ParseFromZeroCopyStream(io::ZeroCopyInputStream* input) {
   io::CodedInputStream coded_input(input);
-  return ParseFromCodedStream(&coded_input) &&
-    coded_input.ConsumedEntireMessage();
+  return (ParseFromCodedStream(&coded_input) &&
+          coded_input.ConsumedEntireMessage());
 }
 
 bool UnknownFieldSet::ParseFromArray(const void* data, int size) {
@@ -244,15 +294,31 @@ void UnknownField::Delete() {
   }
 }
 
-void UnknownField::DeepCopy() {
+// Reset all owned ptrs, a special function for performance, to avoid double
+// owning the ptrs, when we merge from a temporary UnknownFieldSet objects.
+void UnknownField::Reset() {
+  switch (type()) {
+    case UnknownField::TYPE_LENGTH_DELIMITED:
+      length_delimited_.string_value_ = NULL;
+      break;
+    case UnknownField::TYPE_GROUP: {
+      group_ = NULL;
+      break;
+    }
+    default:
+      break;
+  }
+}
+
+void UnknownField::DeepCopy(const UnknownField& other) {
   switch (type()) {
     case UnknownField::TYPE_LENGTH_DELIMITED:
       length_delimited_.string_value_ = new string(
           *length_delimited_.string_value_);
       break;
     case UnknownField::TYPE_GROUP: {
-      UnknownFieldSet* group = new UnknownFieldSet;
-      group->MergeFrom(*group_);
+      UnknownFieldSet* group = new UnknownFieldSet();
+      group->InternalMergeFrom(*group_);
       group_ = group;
       break;
     }
@@ -264,14 +330,14 @@ void UnknownField::DeepCopy() {
 
 void UnknownField::SerializeLengthDelimitedNoTag(
     io::CodedOutputStream* output) const {
-  GOOGLE_DCHECK_EQ(TYPE_LENGTH_DELIMITED, type_);
+  GOOGLE_DCHECK_EQ(TYPE_LENGTH_DELIMITED, type());
   const string& data = *length_delimited_.string_value_;
   output->WriteVarint32(data.size());
-  output->WriteString(data);
+  output->WriteRawMaybeAliased(data.data(), data.size());
 }
 
 uint8* UnknownField::SerializeLengthDelimitedNoTagToArray(uint8* target) const {
-  GOOGLE_DCHECK_EQ(TYPE_LENGTH_DELIMITED, type_);
+  GOOGLE_DCHECK_EQ(TYPE_LENGTH_DELIMITED, type());
   const string& data = *length_delimited_.string_value_;
   target = io::CodedOutputStream::WriteVarint32ToArray(data.size(), target);
   target = io::CodedOutputStream::WriteStringToArray(data, target);