[mojo] Use base::Pickle for Message storage.

base/pickle.cc

 // Copyright (c) 2012 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.
 
 #include "base/pickle.h"
 
 #include <stdlib.h>
 
 #include <algorithm>  // for max()
 #include <limits>
@@ skipping 311 matching lines @@
 }
 
 void Pickle::Resize(size_t new_capacity) {
   CHECK_NE(capacity_after_header_, kCapacityReadOnly);
   capacity_after_header_ = bits::Align(new_capacity, kPayloadUnit);
   void* p = realloc(header_, GetTotalAllocatedSize());
   CHECK(p);
   header_ = reinterpret_cast<Header*>(p);
 }
 
+void* Pickle::ClaimUninitializedBytes(size_t num_bytes) {
+  void* p = ClaimUninitializedBytesInternal(num_bytes);
+  CHECK(p);
+  return p;
+}
+
+void* Pickle::ClaimBytes(size_t num_bytes) {
+  void* p = ClaimUninitializedBytesInternal(num_bytes);
+  CHECK(p);
+  memset(p, 0, num_bytes);
+  return p;
+}
+
 size_t Pickle::GetTotalAllocatedSize() const {
   if (capacity_after_header_ == kCapacityReadOnly)
     return 0;
   return header_size_ + capacity_after_header_;
 }
 
 // static
 const char* Pickle::FindNext(size_t header_size,
                              const char* start,
                              const char* end) {
@@ skipping 35 matching lines @@
 }
 
 template <size_t length> void Pickle::WriteBytesStatic(const void* data) {
   WriteBytesCommon(data, length);
 }
 
 template void Pickle::WriteBytesStatic<2>(const void* data);
 template void Pickle::WriteBytesStatic<4>(const void* data);
 template void Pickle::WriteBytesStatic<8>(const void* data);
 
-inline void Pickle::WriteBytesCommon(const void* data, size_t length) {
+inline void* Pickle::ClaimUninitializedBytesInternal(size_t length) {
   DCHECK_NE(kCapacityReadOnly, capacity_after_header_)
       << "oops: pickle is readonly";
-  MSAN_CHECK_MEM_IS_INITIALIZED(data, length);
   size_t data_len = bits::Align(length, sizeof(uint32_t));
   DCHECK_GE(data_len, length);
 #ifdef ARCH_CPU_64_BITS
   DCHECK_LE(data_len, std::numeric_limits<uint32_t>::max());
 #endif
   DCHECK_LE(write_offset_, std::numeric_limits<uint32_t>::max() - data_len);
   size_t new_size = write_offset_ + data_len;
   if (new_size > capacity_after_header_) {
     size_t new_capacity = capacity_after_header_ * 2;
     const size_t kPickleHeapAlign = 4096;
     if (new_capacity > kPickleHeapAlign)
       new_capacity = bits::Align(new_capacity, kPickleHeapAlign) - kPayloadUnit;
     Resize(std::max(new_capacity, new_size));
   }
 
   char* write = mutable_payload() + write_offset_;
-  memcpy(write, data, length);
-  memset(write + length, 0, data_len - length);
+  memset(write + length, 0, data_len - length);  // Always initialize padding
   header_->payload_size = static_cast<uint32_t>(new_size);
   write_offset_ = new_size;
+  return write;
+}
+
+inline void Pickle::WriteBytesCommon(const void* data, size_t length) {
+  DCHECK_NE(kCapacityReadOnly, capacity_after_header_)
+      << "oops: pickle is readonly";
+  MSAN_CHECK_MEM_IS_INITIALIZED(data, length);
+  void* write = ClaimUninitializedBytesInternal(length);
+  memcpy(write, data, length);
 }
 
 }  // namespace base