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1 // Copyright (c) 2011 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2011 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 #ifndef BASE_SYNC_SOCKET_H_ | 5 #ifndef BASE_SYNC_SOCKET_H_ |
6 #define BASE_SYNC_SOCKET_H_ | 6 #define BASE_SYNC_SOCKET_H_ |
7 #pragma once | 7 #pragma once |
8 | 8 |
9 // A socket abstraction used for sending and receiving plain | 9 // A socket abstraction used for sending and receiving plain |
10 // data. Because they are blocking, they can be used to perform | 10 // data. Because they are blocking, they can be used to perform |
11 // rudimentary cross-process synchronization with low latency. | 11 // rudimentary cross-process synchronization with low latency. |
12 | 12 |
13 #include "base/basictypes.h" | 13 #include "base/basictypes.h" |
14 #if defined(OS_WIN) | 14 #if defined(OS_WIN) |
15 #include <windows.h> | 15 #include <windows.h> |
16 #endif | 16 #endif |
17 #include <sys/types.h> | 17 #include <sys/types.h> |
18 | 18 |
19 #include "base/base_export.h" | 19 #include "base/base_export.h" |
20 #include "base/compiler_specific.h" | |
21 #include "base/synchronization/waitable_event.h" | |
20 | 22 |
21 namespace base { | 23 namespace base { |
22 | 24 |
23 class BASE_EXPORT SyncSocket { | 25 class BASE_EXPORT SyncSocket { |
24 public: | 26 public: |
25 #if defined(OS_WIN) | 27 #if defined(OS_WIN) |
26 typedef HANDLE Handle; | 28 typedef HANDLE Handle; |
27 #else | 29 #else |
28 typedef int Handle; | 30 typedef int Handle; |
29 #endif | 31 #endif |
30 static const Handle kInvalidHandle; | 32 static const Handle kInvalidHandle; |
31 | 33 |
34 SyncSocket(); | |
35 | |
32 // Creates a SyncSocket from a Handle. Used in transport. | 36 // Creates a SyncSocket from a Handle. Used in transport. |
33 explicit SyncSocket(Handle handle) : handle_(handle) { } | 37 explicit SyncSocket(Handle handle) : handle_(handle) {} |
34 ~SyncSocket() { Close(); } | 38 virtual ~SyncSocket(); |
35 | 39 |
36 // Creates an unnamed pair of connected sockets. | 40 // Creates an unnamed pair of connected sockets. |
37 // pair is a pointer to an array of two SyncSockets in which connected socket | 41 // |pair| is an array of two closed SyncSockets (they must not hold a valid |
darin (slow to review)
2012/01/24 18:59:04
please update this comment to reflect the fact tha
tommi (sloooow) - chröme
2012/01/24 21:03:25
Done.
| |
38 // descriptors are returned. Returns true on success, false on failure. | 42 // handle) which will be connected together. |
39 static bool CreatePair(SyncSocket* pair[2]); | 43 static bool CreatePair(SyncSocket* socket_a, SyncSocket* socket_b); |
40 | 44 |
41 // Closes the SyncSocket. Returns true on success, false on failure. | 45 // Closes the SyncSocket. Returns true on success, false on failure. |
42 bool Close(); | 46 virtual bool Close(); |
43 | 47 |
44 // Sends the message to the remote peer of the SyncSocket. | 48 // Sends the message to the remote peer of the SyncSocket. |
45 // Note it is not safe to send messages from the same socket handle by | 49 // Note it is not safe to send messages from the same socket handle by |
46 // multiple threads simultaneously. | 50 // multiple threads simultaneously. |
47 // buffer is a pointer to the data to send. | 51 // buffer is a pointer to the data to send. |
48 // length is the length of the data to send (must be non-zero). | 52 // length is the length of the data to send (must be non-zero). |
49 // Returns the number of bytes sent, or 0 upon failure. | 53 // Returns the number of bytes sent, or 0 upon failure. |
50 size_t Send(const void* buffer, size_t length); | 54 virtual size_t Send(const void* buffer, size_t length); |
51 | 55 |
52 // Receives a message from an SyncSocket. | 56 // Receives a message from an SyncSocket. |
53 // buffer is a pointer to the buffer to receive data. | 57 // buffer is a pointer to the buffer to receive data. |
54 // length is the number of bytes of data to receive (must be non-zero). | 58 // length is the number of bytes of data to receive (must be non-zero). |
55 // Returns the number of bytes received, or 0 upon failure. | 59 // Returns the number of bytes received, or 0 upon failure. |
56 size_t Receive(void* buffer, size_t length); | 60 virtual size_t Receive(void* buffer, size_t length); |
57 | 61 |
58 // Returns the number of bytes available. If non-zero, Receive() will not | 62 // Returns the number of bytes available. If non-zero, Receive() will not |
59 // not block when called. NOTE: Some implementations cannot reliably | 63 // not block when called. NOTE: Some implementations cannot reliably |
60 // determine the number of bytes available so avoid using the returned | 64 // determine the number of bytes available so avoid using the returned |
61 // size as a promise and simply test against zero. | 65 // size as a promise and simply test against zero. |
62 size_t Peek(); | 66 size_t Peek(); |
63 | 67 |
64 // Extracts the contained handle. Used for transferring between | 68 // Extracts the contained handle. Used for transferring between |
65 // processes. | 69 // processes. |
66 Handle handle() const { return handle_; } | 70 Handle handle() const { return handle_; } |
67 | 71 |
68 private: | 72 protected: |
69 Handle handle_; | 73 Handle handle_; |
70 | 74 |
75 private: | |
71 DISALLOW_COPY_AND_ASSIGN(SyncSocket); | 76 DISALLOW_COPY_AND_ASSIGN(SyncSocket); |
72 }; | 77 }; |
73 | 78 |
79 // Derives from SyncSocket and adds support for shutting down the socket from | |
80 // another thread while a blocking Receive or Send is being done from the thread | |
81 // that owns the socket. | |
82 class BASE_EXPORT CancelableSyncSocket : public SyncSocket { | |
83 public: | |
84 CancelableSyncSocket(); | |
85 explicit CancelableSyncSocket(Handle handle); | |
86 virtual ~CancelableSyncSocket() {} | |
87 | |
88 // A way to shut down a socket even if another thread is currently performing | |
89 // a blocking Receive or Send. | |
90 bool Shutdown(); | |
91 | |
92 #if defined(OS_WIN) | |
93 // Since the Linux and Mac implementations actually use a socket, shutting | |
94 // them down from another thread is pretty simple - we can just call | |
95 // shutdown(). However, the Windows implementation relies on named pipes | |
96 // and there isn't a way to cancel a blocking synchronous Read that is | |
97 // supported on <Vista. So, for Windows only, we override these | |
98 // SyncSocket methods in order to support shutting down the 'socket'. | |
99 virtual bool Close() OVERRIDE; | |
100 virtual size_t Send(const void* buffer, size_t length) OVERRIDE; | |
101 virtual size_t Receive(void* buffer, size_t length) OVERRIDE; | |
102 | |
103 static bool CreatePair(CancelableSyncSocket* socket_a, | |
darin (slow to review)
2012/01/24 18:59:04
Other ports don't need to call CreatePair? SyncSo
tommi (sloooow) - chröme
2012/01/24 21:03:25
Other ports don't need their own implementation si
| |
104 CancelableSyncSocket* socket_b); | |
105 #endif | |
106 | |
107 private: | |
108 #if defined(OS_WIN) | |
109 WaitableEvent shutdown_event_; | |
110 WaitableEvent file_operation_; | |
111 #endif | |
112 DISALLOW_COPY_AND_ASSIGN(CancelableSyncSocket); | |
113 }; | |
114 | |
74 } // namespace base | 115 } // namespace base |
75 | 116 |
76 #endif // BASE_SYNC_SOCKET_H_ | 117 #endif // BASE_SYNC_SOCKET_H_ |
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