Mojo: Add a platform interface for shared memory (embedder::PlatformSharedBuffer).

mojo/system/raw_shared_buffer.cc

 // Copyright 2014 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 "mojo/system/raw_shared_buffer.h"
 
 #include "base/logging.h"
 #include "mojo/embedder/platform_handle_utils.h"
 
 namespace mojo {
 namespace system {
 
 // static
 RawSharedBuffer* RawSharedBuffer::Create(size_t num_bytes) {
   DCHECK_GT(num_bytes, 0u);
 
   RawSharedBuffer* rv = new RawSharedBuffer(num_bytes);
   if (!rv->Init()) {
     // We can't just delete it directly, due to the "in destructor" (debug)
     // check.
     scoped_refptr<RawSharedBuffer> deleter(rv);
     return NULL;
   }
 
   return rv;
 }
 
+// static
 RawSharedBuffer* RawSharedBuffer::CreateFromPlatformHandle(
     size_t num_bytes,
     embedder::ScopedPlatformHandle platform_handle) {
   DCHECK_GT(num_bytes, 0u);
 
   RawSharedBuffer* rv = new RawSharedBuffer(num_bytes);
   if (!rv->InitFromPlatformHandle(platform_handle.Pass())) {
     // We can't just delete it directly, due to the "in destructor" (debug)
     // check.
     scoped_refptr<RawSharedBuffer> deleter(rv);
     return NULL;
   }
 
   return rv;
 }
 
-scoped_ptr<RawSharedBufferMapping> RawSharedBuffer::Map(size_t offset,
-                                                        size_t length) {
+size_t RawSharedBuffer::GetNumBytes() const {
+  return num_bytes_;
+}
+
+scoped_ptr<embedder::PlatformSharedBufferMapping> RawSharedBuffer::Map(
+    size_t offset,
+    size_t length) {
   if (!IsValidMap(offset, length))
-    return scoped_ptr<RawSharedBufferMapping>();
+    return scoped_ptr<embedder::PlatformSharedBufferMapping>();
 
   return MapNoCheck(offset, length);
 }
 
 bool RawSharedBuffer::IsValidMap(size_t offset, size_t length) {
   if (offset > num_bytes_ || length == 0)
     return false;
 
   // Note: This is an overflow-safe check of |offset + length > num_bytes_|
   // (that |num_bytes >= offset| is verified above).
   if (length > num_bytes_ - offset)
     return false;
 
   return true;
 }
 
-scoped_ptr<RawSharedBufferMapping> RawSharedBuffer::MapNoCheck(size_t offset,
-                                                               size_t length) {
+scoped_ptr<embedder::PlatformSharedBufferMapping> RawSharedBuffer::MapNoCheck(
+    size_t offset,
+    size_t length) {
   DCHECK(IsValidMap(offset, length));
   return MapImpl(offset, length);
 }
 
 embedder::ScopedPlatformHandle RawSharedBuffer::DuplicatePlatformHandle() {
   return embedder::DuplicatePlatformHandle(handle_.get());
 }
 
 embedder::ScopedPlatformHandle RawSharedBuffer::PassPlatformHandle() {
   DCHECK(HasOneRef());
   return handle_.Pass();
 }
 
 RawSharedBuffer::RawSharedBuffer(size_t num_bytes) : num_bytes_(num_bytes) {
 }
 
 RawSharedBuffer::~RawSharedBuffer() {
 }
 
+RawSharedBufferMapping::~RawSharedBufferMapping() {
+  Unmap();
+}
+
+void* RawSharedBufferMapping::GetBase() const {
+  return base_;
+}
+
+size_t RawSharedBufferMapping::GetLength() const {
+  return length_;
+}
+
 }  // namespace system
 }  // namespace mojo