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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_EMBEDDER_H_ | |
6 #define MOJO_EDK_EMBEDDER_EMBEDDER_H_ | |
7 | |
8 #include "base/callback.h" | |
9 #include "base/memory/ref_counted.h" | |
10 #include "base/memory/scoped_ptr.h" | |
11 #include "base/task_runner.h" | |
12 #include "mojo/edk/embedder/channel_info_forward.h" | |
13 #include "mojo/edk/embedder/scoped_platform_handle.h" | |
14 #include "mojo/edk/system/system_impl_export.h" | |
15 #include "mojo/public/cpp/system/message_pipe.h" | |
16 | |
17 namespace mojo { | |
18 namespace embedder { | |
19 | |
20 struct Configuration; | |
21 class PlatformSupport; | |
22 | |
23 // Must be called first, or just after setting configuration parameters, | |
24 // to initialize the (global, singleton) system. | |
25 MOJO_SYSTEM_IMPL_EXPORT void Init(scoped_ptr<PlatformSupport> platform_support); | |
26 | |
27 // Returns the global configuration. In general there should be no need to | |
28 // change the configuration, but if you do so this must be done before calling | |
29 // |Init()|. | |
30 MOJO_SYSTEM_IMPL_EXPORT Configuration* GetConfiguration(); | |
31 | |
32 // A "channel" is a connection on top of an OS "pipe", on top of which Mojo | |
33 // message pipes (etc.) can be multiplexed. It must "live" on some I/O thread. | |
34 // | |
35 // There are two channel creation APIs: |CreateChannelOnIOThread()| creates a | |
36 // channel synchronously and must be called from the I/O thread, while | |
37 // |CreateChannel()| is asynchronous and may be called from any thread. | |
38 // |DestroyChannel()| is used to destroy the channel in either case and may be | |
39 // called from any thread, but completes synchronously when called from the I/O | |
40 // thread. | |
41 // | |
42 // Both creation functions have a |platform_handle| argument, which should be an | |
43 // OS-dependent handle to one side of a suitable bidirectional OS "pipe" (e.g., | |
44 // a file descriptor to a socket on POSIX, a handle to a named pipe on Windows); | |
45 // this "pipe" should be connected and ready for operation (e.g., to be written | |
46 // to or read from). | |
47 // | |
48 // Both (synchronously) return a handle to the bootstrap message pipe on the | |
49 // channel that was (or is to be) created, or |MOJO_HANDLE_INVALID| on error | |
50 // (but note that this will happen only if, e.g., the handle table is full). | |
51 // This message pipe may be used immediately, but since channel operation | |
52 // actually begins asynchronously, other errors may still occur (e.g., if the | |
53 // other end of the "pipe" is closed) and be reported in the usual way to the | |
54 // returned handle. | |
55 // | |
56 // (E.g., a message written immediately to the returned handle will be queued | |
57 // and the handle immediately closed, before the channel begins operation. In | |
58 // this case, the channel should connect as usual, send the queued message, and | |
59 // report that the handle was closed to the other side. The message sent may | |
60 // have other handles, so there may still be message pipes "on" this channel.) | |
61 // | |
62 // Both also produce a |ChannelInfo*| (a pointer to an opaque object) -- the | |
63 // first synchronously and second asynchronously. | |
64 // | |
65 // The destruction functions are similarly synchronous and asynchronous, | |
66 // respectively, and take the |ChannelInfo*| produced by the creation functions. | |
67 // | |
68 // TODO(vtl): Figure out channel teardown. | |
69 | |
70 // Creates a channel; must only be called from the I/O thread. |platform_handle| | |
71 // should be a handle to a connected OS "pipe". Eventually (even on failure), | |
72 // the "out" value |*channel_info| should be passed to |DestoryChannel()| to | |
73 // tear down the channel. Returns a handle to the bootstrap message pipe. | |
74 MOJO_SYSTEM_IMPL_EXPORT ScopedMessagePipeHandle | |
75 CreateChannelOnIOThread(ScopedPlatformHandle platform_handle, | |
76 ChannelInfo** channel_info); | |
77 | |
78 typedef base::Callback<void(ChannelInfo*)> DidCreateChannelCallback; | |
79 // Creates a channel asynchronously; may be called from any thread. | |
80 // |platform_handle| should be a handle to a connected OS "pipe". | |
81 // |io_thread_task_runner| should be the |TaskRunner| for the I/O thread. | |
82 // |callback| should be the callback to call with the |ChannelInfo*|, which | |
83 // should eventually be passed to |DestroyChannel()| to tear down the channel; | |
84 // the callback will be called using |callback_thread_task_runner| if that is | |
85 // non-null, or otherwise it will be called using |io_thread_task_runner|. | |
86 // Returns a handle to the bootstrap message pipe. | |
87 MOJO_SYSTEM_IMPL_EXPORT ScopedMessagePipeHandle | |
88 CreateChannel(ScopedPlatformHandle platform_handle, | |
89 scoped_refptr<base::TaskRunner> io_thread_task_runner, | |
90 DidCreateChannelCallback callback, | |
91 scoped_refptr<base::TaskRunner> callback_thread_task_runner); | |
92 | |
93 // Destroys a channel that was created using |CreateChannel()| (or | |
94 // |CreateChannelOnIOThread()|); may be called from any thread. |channel_info| | |
95 // should be the value provided to the callback to |CreateChannel()| (or | |
96 // returned by |CreateChannelOnIOThread()|). If called from the I/O thread, this | |
97 // will complete synchronously (in particular, it will post no tasks). | |
98 MOJO_SYSTEM_IMPL_EXPORT void DestroyChannel(ChannelInfo* channel_info); | |
99 | |
100 // Inform the channel that it will soon be destroyed (doing so is optional). | |
101 // This may be called from any thread, but the caller must ensure that this is | |
102 // called before |DestroyChannel()|. | |
103 MOJO_SYSTEM_IMPL_EXPORT void WillDestroyChannelSoon(ChannelInfo* channel_info); | |
104 | |
105 // Creates a |MojoHandle| that wraps the given |PlatformHandle| (taking | |
106 // ownership of it). This |MojoHandle| can then, e.g., be passed through message | |
107 // pipes. Note: This takes ownership (and thus closes) |platform_handle| even on | |
108 // failure, which is different from what you'd expect from a Mojo API, but it | |
109 // makes for a more convenient embedder API. | |
110 MOJO_SYSTEM_IMPL_EXPORT MojoResult | |
111 CreatePlatformHandleWrapper(ScopedPlatformHandle platform_handle, | |
112 MojoHandle* platform_handle_wrapper_handle); | |
113 // Retrieves the |PlatformHandle| that was wrapped into a |MojoHandle| (using | |
114 // |CreatePlatformHandleWrapper()| above). Note that the |MojoHandle| must still | |
115 // be closed separately. | |
116 MOJO_SYSTEM_IMPL_EXPORT MojoResult | |
117 PassWrappedPlatformHandle(MojoHandle platform_handle_wrapper_handle, | |
118 ScopedPlatformHandle* platform_handle); | |
119 | |
120 // Start waiting the handle asynchronously. On success, |callback| will be | |
121 // called exactly once, when |handle| satisfies a signal in |signals| or it | |
122 // becomes known that it will never do so. |callback| will be executed on an | |
123 // arbitrary thread. It must not call any Mojo system or embedder functions. | |
124 MOJO_SYSTEM_IMPL_EXPORT MojoResult | |
125 AsyncWait(MojoHandle handle, | |
126 MojoHandleSignals signals, | |
127 base::Callback<void(MojoResult)> callback); | |
128 | |
129 } // namespace embedder | |
130 } // namespace mojo | |
131 | |
132 #endif // MOJO_EDK_EMBEDDER_EMBEDDER_H_ | |
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