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
10namespace mojo {
11namespace embedder {
12
13// static
14SimplePlatformSharedBuffer* 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 nullptr;
24  }
25
26  return rv;
27}
28
29// static
30SimplePlatformSharedBuffer*
31SimplePlatformSharedBuffer::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 nullptr;
42  }
43
44  return rv;
45}
46
47size_t SimplePlatformSharedBuffer::GetNumBytes() const {
48  return num_bytes_;
49}
50
51scoped_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
60bool 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
72scoped_ptr<PlatformSharedBufferMapping> SimplePlatformSharedBuffer::MapNoCheck(
73    size_t offset,
74    size_t length) {
75  DCHECK(IsValidMap(offset, length));
76  return MapImpl(offset, length);
77}
78
79ScopedPlatformHandle SimplePlatformSharedBuffer::DuplicatePlatformHandle() {
80  return mojo::embedder::DuplicatePlatformHandle(handle_.get());
81}
82
83ScopedPlatformHandle SimplePlatformSharedBuffer::PassPlatformHandle() {
84  DCHECK(HasOneRef());
85  return handle_.Pass();
86}
87
88SimplePlatformSharedBuffer::SimplePlatformSharedBuffer(size_t num_bytes)
89    : num_bytes_(num_bytes) {
90}
91
92SimplePlatformSharedBuffer::~SimplePlatformSharedBuffer() {
93}
94
95SimplePlatformSharedBufferMapping::~SimplePlatformSharedBufferMapping() {
96  Unmap();
97}
98
99void* SimplePlatformSharedBufferMapping::GetBase() const {
100  return base_;
101}
102
103size_t SimplePlatformSharedBufferMapping::GetLength() const {
104  return length_;
105}
106
107}  // namespace embedder
108}  // namespace mojo
109