Improved memory usage while applying patch....

courgette/streams.cc

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Streams classes.
 //
 // These memory-resident streams are used for serializing data into a sequential
 // region of memory.
 //
 // Streams are divided into SourceStreams for reading and SinkStreams for
@@ skipping 193 matching lines @@
 
 void SinkStream::WriteSizeVarint32(size_t value) {
   uint32 narrowed_value = static_cast<uint32>(value);
   // On 32-bit, the compiler should figure out this test always fails.
   LOG_ASSERT(value == narrowed_value);
   WriteVarint32(narrowed_value);
 }
 
 void SinkStream::Append(SinkStream* other) {
   Write(other->buffer_.c_str(), other->buffer_.size());
-  other->buffer_.clear();
-  other->buffer_.reserve(0);  // Non-binding request to reduce storage.
+  other->Retire();
+}
+
+void SinkStream::Retire() {
+  buffer_.clear();
+  buffer_.reserve(0);  // Non-binding request to reduce storage.
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 
 SourceStreamSet::SourceStreamSet()
     : count_(kMaxStreams) {
 }
 
 SourceStreamSet::~SourceStreamSet() {
 }
@@ skipping 102 matching lines @@
   for (size_t i = 0; i < count_; ++i) {
     header->WriteSizeVarint32(stream(i)->Length());
   }
 }
 
 // Writes |this| to |combined_stream|.  See SourceStreamSet::Init for the layout
 // of the stream metadata and contents.
 bool SinkStreamSet::CopyTo(SinkStream *combined_stream) {
   SinkStream header;
   CopyHeaderTo(&header);
+
+  // Reserve the correct amount of storage.
+  size_t length = header.Length();
+  for (size_t i = 0; i < count_; ++i) {
+    length += stream(i)->Length();
+  }
+  combined_stream->Reserve(length);
+
   combined_stream->Append(&header);
   for (size_t i = 0; i < count_; ++i) {
     combined_stream->Append(stream(i));
   }
   return true;
 }
 
 bool SinkStreamSet::WriteSet(SinkStreamSet* set) {
   uint32 lengths[kMaxStreams];
   // 'stream_count' includes all non-empty streams and all empty stream numbered
@@ skipping 12 matching lines @@
     control_stream->WriteSizeVarint32(lengths[i]);
   }
 
   for (size_t i = 0; i < stream_count; ++i) {
     this->stream(i)->Append(set->stream(i));
   }
   return true;
 }
 
 }  // namespace