src/mojo/embedder/simple_platform_shared_buffer.cc

   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/embedder/simple_platform_shared_buffer.h"
   6
   7 #include "base/logging.h"
   8 #include "mojo/embedder/platform_handle_utils.h"
   9
  10 namespace mojo {
  11 namespace embedder {
  12
  13 // static
  14 SimplePlatformSharedBuffer* SimplePlatformSharedBuffer::Create(
  15     size_t num_bytes) {
  16   DCHECK_GT(num_bytes, 0u);
  17
  18   SimplePlatformSharedBuffer* rv = new SimplePlatformSharedBuffer(num_bytes);
  19   if (!rv->Init()) {
  20     // We can't just delete it directly, due to the "in destructor" (debug)
  21     // check.
  22     scoped_refptr<SimplePlatformSharedBuffer> deleter(rv);
  23     return NULL;
  24   }
  25
  26   return rv;
  27 }
  28
  29 // static
  30 SimplePlatformSharedBuffer*
  31 SimplePlatformSharedBuffer::CreateFromPlatformHandle(
  32     size_t num_bytes,
  33     ScopedPlatformHandle platform_handle) {
  34   DCHECK_GT(num_bytes, 0u);
  35
  36   SimplePlatformSharedBuffer* rv = new SimplePlatformSharedBuffer(num_bytes);
  37   if (!rv->InitFromPlatformHandle(platform_handle.Pass())) {
  38     // We can't just delete it directly, due to the "in destructor" (debug)
  39     // check.
  40     scoped_refptr<SimplePlatformSharedBuffer> deleter(rv);
  41     return NULL;
  42   }
  43
  44   return rv;
  45 }
  46
  47 size_t SimplePlatformSharedBuffer::GetNumBytes() const {
  48   return num_bytes_;
  49 }
  50
  51 scoped_ptr<PlatformSharedBufferMapping> SimplePlatformSharedBuffer::Map(
  52     size_t offset,
  53     size_t length) {
  54   if (!IsValidMap(offset, length))
  55     return scoped_ptr<PlatformSharedBufferMapping>();
  56
  57   return MapNoCheck(offset, length);
  58 }
  59
  60 bool SimplePlatformSharedBuffer::IsValidMap(size_t offset, size_t length) {
  61   if (offset > num_bytes_ || length == 0)
  62     return false;
  63
  64   // Note: This is an overflow-safe check of |offset + length > num_bytes_|
  65   // (that |num_bytes >= offset| is verified above).
  66   if (length > num_bytes_ - offset)
  67     return false;
  68
  69   return true;
  70 }
  71
  72 scoped_ptr<PlatformSharedBufferMapping> SimplePlatformSharedBuffer::MapNoCheck(
  73     size_t offset,
  74     size_t length) {
  75   DCHECK(IsValidMap(offset, length));
  76   return MapImpl(offset, length);
  77 }
  78
  79 ScopedPlatformHandle SimplePlatformSharedBuffer::DuplicatePlatformHandle() {
  80   return mojo::embedder::DuplicatePlatformHandle(handle_.get());
  81 }
  82
  83 ScopedPlatformHandle SimplePlatformSharedBuffer::PassPlatformHandle() {
  84   DCHECK(HasOneRef());
  85   return handle_.Pass();
  86 }
  87
  88 SimplePlatformSharedBuffer::SimplePlatformSharedBuffer(size_t num_bytes)
  89     : num_bytes_(num_bytes) {
  90 }
  91
  92 SimplePlatformSharedBuffer::~SimplePlatformSharedBuffer() {
  93 }
  94
  95 SimplePlatformSharedBufferMapping::~SimplePlatformSharedBufferMapping() {
  96   Unmap();
  97 }
  98
  99 void* SimplePlatformSharedBufferMapping::GetBase() const {
 100   return base_;
 101 }
 102
 103 size_t SimplePlatformSharedBufferMapping::GetLength() const {
 104   return length_;
 105 }
 106
 107 }  // namespace embedder
 108 }  // namespace mojo