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      1 // Copyright 2014 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "mojo/system/raw_shared_buffer.h"
      6 
      7 #include "base/logging.h"
      8 #include "mojo/embedder/platform_handle_utils.h"
      9 
     10 namespace mojo {
     11 namespace system {
     12 
     13 // static
     14 RawSharedBuffer* RawSharedBuffer::Create(size_t num_bytes) {
     15   DCHECK_GT(num_bytes, 0u);
     16 
     17   RawSharedBuffer* rv = new RawSharedBuffer(num_bytes);
     18   if (!rv->Init()) {
     19     // We can't just delete it directly, due to the "in destructor" (debug)
     20     // check.
     21     scoped_refptr<RawSharedBuffer> deleter(rv);
     22     return NULL;
     23   }
     24 
     25   return rv;
     26 }
     27 
     28 RawSharedBuffer* RawSharedBuffer::CreateFromPlatformHandle(
     29     size_t num_bytes,
     30     embedder::ScopedPlatformHandle platform_handle) {
     31   DCHECK_GT(num_bytes, 0u);
     32 
     33   RawSharedBuffer* rv = new RawSharedBuffer(num_bytes);
     34   if (!rv->InitFromPlatformHandle(platform_handle.Pass())) {
     35     // We can't just delete it directly, due to the "in destructor" (debug)
     36     // check.
     37     scoped_refptr<RawSharedBuffer> deleter(rv);
     38     return NULL;
     39   }
     40 
     41   return rv;
     42 }
     43 
     44 scoped_ptr<RawSharedBufferMapping> RawSharedBuffer::Map(size_t offset,
     45                                                         size_t length) {
     46   if (!IsValidMap(offset, length))
     47     return scoped_ptr<RawSharedBufferMapping>();
     48 
     49   return MapNoCheck(offset, length);
     50 }
     51 
     52 bool RawSharedBuffer::IsValidMap(size_t offset, size_t length) {
     53   if (offset > num_bytes_ || length == 0)
     54     return false;
     55 
     56   // Note: This is an overflow-safe check of |offset + length > num_bytes_|
     57   // (that |num_bytes >= offset| is verified above).
     58   if (length > num_bytes_ - offset)
     59     return false;
     60 
     61   return true;
     62 }
     63 
     64 scoped_ptr<RawSharedBufferMapping> RawSharedBuffer::MapNoCheck(size_t offset,
     65                                                                size_t length) {
     66   DCHECK(IsValidMap(offset, length));
     67   return MapImpl(offset, length);
     68 }
     69 
     70 embedder::ScopedPlatformHandle RawSharedBuffer::DuplicatePlatformHandle() {
     71   return embedder::DuplicatePlatformHandle(handle_.get());
     72 }
     73 
     74 embedder::ScopedPlatformHandle RawSharedBuffer::PassPlatformHandle() {
     75   DCHECK(HasOneRef());
     76   return handle_.Pass();
     77 }
     78 
     79 RawSharedBuffer::RawSharedBuffer(size_t num_bytes) : num_bytes_(num_bytes) {
     80 }
     81 
     82 RawSharedBuffer::~RawSharedBuffer() {
     83 }
     84 
     85 }  // namespace system
     86 }  // namespace mojo
     87