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1 // Copyright 2014 The Chromium Authors. All rights reserved. | 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 | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 // This file provides a C++ wrapping around the Mojo C API for shared buffers, | 5 // This file provides a C++ wrapping around the Mojo C API for shared buffers, |
6 // replacing the prefix of "Mojo" with a "mojo" namespace, and using more | 6 // replacing the prefix of "Mojo" with a "mojo" namespace, and using more |
7 // strongly-typed representations of |MojoHandle|s. | 7 // strongly-typed representations of |MojoHandle|s. |
8 // | 8 // |
9 // Please see "mojo/public/c/system/buffer.h" for complete documentation of the | 9 // Please see "mojo/public/c/system/buffer.h" for complete documentation of the |
10 // API. | 10 // API. |
11 | 11 |
12 #ifndef MOJO_PUBLIC_CPP_SYSTEM_BUFFER_H_ | 12 #ifndef MOJO_PUBLIC_CPP_SYSTEM_BUFFER_H_ |
13 #define MOJO_PUBLIC_CPP_SYSTEM_BUFFER_H_ | 13 #define MOJO_PUBLIC_CPP_SYSTEM_BUFFER_H_ |
14 | 14 |
15 #include <assert.h> | |
16 #include <stdint.h> | 15 #include <stdint.h> |
17 | 16 |
18 #include "base/compiler_specific.h" | 17 #include "base/compiler_specific.h" |
| 18 #include "base/logging.h" |
19 #include "mojo/public/c/system/buffer.h" | 19 #include "mojo/public/c/system/buffer.h" |
20 #include "mojo/public/cpp/system/handle.h" | 20 #include "mojo/public/cpp/system/handle.h" |
21 #include "mojo/public/cpp/system/macros.h" | 21 #include "mojo/public/cpp/system/macros.h" |
22 | 22 |
23 namespace mojo { | 23 namespace mojo { |
24 | 24 |
25 // A strongly-typed representation of a |MojoHandle| referring to a shared | 25 // A strongly-typed representation of a |MojoHandle| referring to a shared |
26 // buffer. | 26 // buffer. |
27 class SharedBufferHandle : public Handle { | 27 class SharedBufferHandle : public Handle { |
28 public: | 28 public: |
29 SharedBufferHandle() {} | 29 SharedBufferHandle() {} |
30 explicit SharedBufferHandle(MojoHandle value) : Handle(value) {} | 30 explicit SharedBufferHandle(MojoHandle value) : Handle(value) {} |
31 | 31 |
32 // Copying and assignment allowed. | 32 // Copying and assignment allowed. |
33 }; | 33 }; |
34 | 34 |
35 static_assert(sizeof(SharedBufferHandle) == sizeof(Handle), | 35 static_assert(sizeof(SharedBufferHandle) == sizeof(Handle), |
36 "Bad size for C++ SharedBufferHandle"); | 36 "Bad size for C++ SharedBufferHandle"); |
37 | 37 |
38 typedef ScopedHandleBase<SharedBufferHandle> ScopedSharedBufferHandle; | 38 typedef ScopedHandleBase<SharedBufferHandle> ScopedSharedBufferHandle; |
39 static_assert(sizeof(ScopedSharedBufferHandle) == sizeof(SharedBufferHandle), | 39 static_assert(sizeof(ScopedSharedBufferHandle) == sizeof(SharedBufferHandle), |
40 "Bad size for C++ ScopedSharedBufferHandle"); | 40 "Bad size for C++ ScopedSharedBufferHandle"); |
41 | 41 |
42 // Creates a shared buffer. See |MojoCreateSharedBuffer()| for complete | 42 // Creates a shared buffer. See |MojoCreateSharedBuffer()| for complete |
43 // documentation. | 43 // documentation. |
44 inline MojoResult CreateSharedBuffer( | 44 inline MojoResult CreateSharedBuffer( |
45 const MojoCreateSharedBufferOptions* options, | 45 const MojoCreateSharedBufferOptions* options, |
46 uint64_t num_bytes, | 46 uint64_t num_bytes, |
47 ScopedSharedBufferHandle* shared_buffer) { | 47 ScopedSharedBufferHandle* shared_buffer) { |
48 assert(shared_buffer); | 48 DCHECK(shared_buffer); |
49 SharedBufferHandle handle; | 49 SharedBufferHandle handle; |
50 MojoResult rv = | 50 MojoResult rv = |
51 MojoCreateSharedBuffer(options, num_bytes, handle.mutable_value()); | 51 MojoCreateSharedBuffer(options, num_bytes, handle.mutable_value()); |
52 // Reset even on failure (reduces the chances that a "stale"/incorrect handle | 52 // Reset even on failure (reduces the chances that a "stale"/incorrect handle |
53 // will be used). | 53 // will be used). |
54 shared_buffer->reset(handle); | 54 shared_buffer->reset(handle); |
55 return rv; | 55 return rv; |
56 } | 56 } |
57 | 57 |
58 // Duplicates a handle to a buffer, most commonly so that the buffer can be | 58 // Duplicates a handle to a buffer, most commonly so that the buffer can be |
59 // shared with other applications. See |MojoDuplicateBufferHandle()| for | 59 // shared with other applications. See |MojoDuplicateBufferHandle()| for |
60 // complete documentation. | 60 // complete documentation. |
61 // | 61 // |
62 // TODO(ggowan): Rename this to DuplicateBufferHandle since it is making another | 62 // TODO(ggowan): Rename this to DuplicateBufferHandle since it is making another |
63 // handle to the same buffer, not duplicating the buffer itself. | 63 // handle to the same buffer, not duplicating the buffer itself. |
64 // | 64 // |
65 // TODO(vtl): This (and also the functions below) are templatized to allow for | 65 // TODO(vtl): This (and also the functions below) are templatized to allow for |
66 // future/other buffer types. A bit "safer" would be to overload this function | 66 // future/other buffer types. A bit "safer" would be to overload this function |
67 // manually. (The template enforces that the in and out handles be of the same | 67 // manually. (The template enforces that the in and out handles be of the same |
68 // type.) | 68 // type.) |
69 template <class BufferHandleType> | 69 template <class BufferHandleType> |
70 inline MojoResult DuplicateBuffer( | 70 inline MojoResult DuplicateBuffer( |
71 BufferHandleType buffer, | 71 BufferHandleType buffer, |
72 const MojoDuplicateBufferHandleOptions* options, | 72 const MojoDuplicateBufferHandleOptions* options, |
73 ScopedHandleBase<BufferHandleType>* new_buffer) { | 73 ScopedHandleBase<BufferHandleType>* new_buffer) { |
74 assert(new_buffer); | 74 DCHECK(new_buffer); |
75 BufferHandleType handle; | 75 BufferHandleType handle; |
76 MojoResult rv = MojoDuplicateBufferHandle( | 76 MojoResult rv = MojoDuplicateBufferHandle( |
77 buffer.value(), options, handle.mutable_value()); | 77 buffer.value(), options, handle.mutable_value()); |
78 // Reset even on failure (reduces the chances that a "stale"/incorrect handle | 78 // Reset even on failure (reduces the chances that a "stale"/incorrect handle |
79 // will be used). | 79 // will be used). |
80 new_buffer->reset(handle); | 80 new_buffer->reset(handle); |
81 return rv; | 81 return rv; |
82 } | 82 } |
83 | 83 |
84 // Maps a part of a buffer (specified by |buffer|, |offset|, and |num_bytes|) | 84 // Maps a part of a buffer (specified by |buffer|, |offset|, and |num_bytes|) |
85 // into memory. See |MojoMapBuffer()| for complete documentation. | 85 // into memory. See |MojoMapBuffer()| for complete documentation. |
86 template <class BufferHandleType> | 86 template <class BufferHandleType> |
87 inline MojoResult MapBuffer(BufferHandleType buffer, | 87 inline MojoResult MapBuffer(BufferHandleType buffer, |
88 uint64_t offset, | 88 uint64_t offset, |
89 uint64_t num_bytes, | 89 uint64_t num_bytes, |
90 void** pointer, | 90 void** pointer, |
91 MojoMapBufferFlags flags) { | 91 MojoMapBufferFlags flags) { |
92 assert(buffer.is_valid()); | 92 DCHECK(buffer.is_valid()); |
93 return MojoMapBuffer(buffer.value(), offset, num_bytes, pointer, flags); | 93 return MojoMapBuffer(buffer.value(), offset, num_bytes, pointer, flags); |
94 } | 94 } |
95 | 95 |
96 // Unmaps a part of a buffer that was previously mapped with |MapBuffer()|. | 96 // Unmaps a part of a buffer that was previously mapped with |MapBuffer()|. |
97 // See |MojoUnmapBuffer()| for complete documentation. | 97 // See |MojoUnmapBuffer()| for complete documentation. |
98 inline MojoResult UnmapBuffer(void* pointer) { | 98 inline MojoResult UnmapBuffer(void* pointer) { |
99 assert(pointer); | 99 DCHECK(pointer); |
100 return MojoUnmapBuffer(pointer); | 100 return MojoUnmapBuffer(pointer); |
101 } | 101 } |
102 | 102 |
103 // A wrapper class that automatically creates a shared buffer and owns the | 103 // A wrapper class that automatically creates a shared buffer and owns the |
104 // handle. | 104 // handle. |
105 class SharedBuffer { | 105 class SharedBuffer { |
106 public: | 106 public: |
107 explicit SharedBuffer(uint64_t num_bytes); | 107 explicit SharedBuffer(uint64_t num_bytes); |
108 SharedBuffer(uint64_t num_bytes, | 108 SharedBuffer(uint64_t num_bytes, |
109 const MojoCreateSharedBufferOptions& options); | 109 const MojoCreateSharedBufferOptions& options); |
110 ~SharedBuffer(); | 110 ~SharedBuffer(); |
111 | 111 |
112 ScopedSharedBufferHandle handle; | 112 ScopedSharedBufferHandle handle; |
113 }; | 113 }; |
114 | 114 |
115 inline SharedBuffer::SharedBuffer(uint64_t num_bytes) { | 115 inline SharedBuffer::SharedBuffer(uint64_t num_bytes) { |
116 MojoResult result = CreateSharedBuffer(nullptr, num_bytes, &handle); | 116 MojoResult result = CreateSharedBuffer(nullptr, num_bytes, &handle); |
117 ALLOW_UNUSED_LOCAL(result); | 117 ALLOW_UNUSED_LOCAL(result); |
118 assert(result == MOJO_RESULT_OK); | 118 DCHECK_EQ(MOJO_RESULT_OK, result); |
119 } | 119 } |
120 | 120 |
121 inline SharedBuffer::SharedBuffer( | 121 inline SharedBuffer::SharedBuffer( |
122 uint64_t num_bytes, | 122 uint64_t num_bytes, |
123 const MojoCreateSharedBufferOptions& options) { | 123 const MojoCreateSharedBufferOptions& options) { |
124 MojoResult result = CreateSharedBuffer(&options, num_bytes, &handle); | 124 MojoResult result = CreateSharedBuffer(&options, num_bytes, &handle); |
125 ALLOW_UNUSED_LOCAL(result); | 125 ALLOW_UNUSED_LOCAL(result); |
126 assert(result == MOJO_RESULT_OK); | 126 DCHECK_EQ(MOJO_RESULT_OK, result); |
127 } | 127 } |
128 | 128 |
129 inline SharedBuffer::~SharedBuffer() { | 129 inline SharedBuffer::~SharedBuffer() { |
130 } | 130 } |
131 | 131 |
132 } // namespace mojo | 132 } // namespace mojo |
133 | 133 |
134 #endif // MOJO_PUBLIC_CPP_SYSTEM_BUFFER_H_ | 134 #endif // MOJO_PUBLIC_CPP_SYSTEM_BUFFER_H_ |
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