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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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