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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 #ifndef MOJO_EDK_EMBEDDER_SIMPLE_PLATFORM_SHARED_BUFFER_H_ | |
6 #define MOJO_EDK_EMBEDDER_SIMPLE_PLATFORM_SHARED_BUFFER_H_ | |
7 | |
8 #include <stddef.h> | |
9 | |
10 #include "base/macros.h" | |
11 #include "mojo/edk/embedder/platform_shared_buffer.h" | |
12 #include "mojo/edk/system/system_impl_export.h" | |
13 | |
14 namespace mojo { | |
15 namespace embedder { | |
16 | |
17 // A simple implementation of |PlatformSharedBuffer|. | |
18 class MOJO_SYSTEM_IMPL_EXPORT SimplePlatformSharedBuffer | |
19 : public PlatformSharedBuffer { | |
20 public: | |
21 // Creates a shared buffer of size |num_bytes| bytes (initially zero-filled). | |
22 // |num_bytes| must be nonzero. Returns null on failure. | |
23 static SimplePlatformSharedBuffer* Create(size_t num_bytes); | |
24 | |
25 static SimplePlatformSharedBuffer* CreateFromPlatformHandle( | |
26 size_t num_bytes, | |
27 ScopedPlatformHandle platform_handle); | |
28 | |
29 // |PlatformSharedBuffer| implementation: | |
30 size_t GetNumBytes() const override; | |
31 scoped_ptr<PlatformSharedBufferMapping> Map(size_t offset, | |
32 size_t length) override; | |
33 bool IsValidMap(size_t offset, size_t length) override; | |
34 scoped_ptr<PlatformSharedBufferMapping> MapNoCheck(size_t offset, | |
35 size_t length) override; | |
36 ScopedPlatformHandle DuplicatePlatformHandle() override; | |
37 ScopedPlatformHandle PassPlatformHandle() override; | |
38 | |
39 private: | |
40 explicit SimplePlatformSharedBuffer(size_t num_bytes); | |
41 ~SimplePlatformSharedBuffer() override; | |
42 | |
43 // Implemented in simple_platform_shared_buffer_{posix,win}.cc: | |
44 | |
45 // This is called by |Create()| before this object is given to anyone. | |
46 bool Init(); | |
47 | |
48 // This is like |Init()|, but for |CreateFromPlatformHandle()|. (Note: It | |
49 // should verify that |platform_handle| is an appropriate handle for the | |
50 // claimed |num_bytes_|.) | |
51 bool InitFromPlatformHandle(ScopedPlatformHandle platform_handle); | |
52 | |
53 // The platform-dependent part of |Map()|; doesn't check arguments. | |
54 scoped_ptr<PlatformSharedBufferMapping> MapImpl(size_t offset, size_t length); | |
55 | |
56 const size_t num_bytes_; | |
57 | |
58 // This is set in |Init()|/|InitFromPlatformHandle()| and never modified | |
59 // (except by |PassPlatformHandle()|; see the comments above its declaration), | |
60 // hence does not need to be protected by a lock. | |
61 ScopedPlatformHandle handle_; | |
62 | |
63 DISALLOW_COPY_AND_ASSIGN(SimplePlatformSharedBuffer); | |
64 }; | |
65 | |
66 // An implementation of |PlatformSharedBufferMapping|, produced by | |
67 // |SimplePlatformSharedBuffer|. | |
68 class MOJO_SYSTEM_IMPL_EXPORT SimplePlatformSharedBufferMapping | |
69 : public PlatformSharedBufferMapping { | |
70 public: | |
71 ~SimplePlatformSharedBufferMapping() override; | |
72 | |
73 void* GetBase() const override; | |
74 size_t GetLength() const override; | |
75 | |
76 private: | |
77 friend class SimplePlatformSharedBuffer; | |
78 | |
79 SimplePlatformSharedBufferMapping(void* base, | |
80 size_t length, | |
81 void* real_base, | |
82 size_t real_length) | |
83 : base_(base), | |
84 length_(length), | |
85 real_base_(real_base), | |
86 real_length_(real_length) {} | |
87 void Unmap(); | |
88 | |
89 void* const base_; | |
90 const size_t length_; | |
91 | |
92 void* const real_base_; | |
93 const size_t real_length_; | |
94 | |
95 DISALLOW_COPY_AND_ASSIGN(SimplePlatformSharedBufferMapping); | |
96 }; | |
97 | |
98 } // namespace embedder | |
99 } // namespace mojo | |
100 | |
101 #endif // MOJO_EDK_EMBEDDER_SIMPLE_PLATFORM_SHARED_BUFFER_H_ | |
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