Index: base/files/file_descriptor_watcher_posix.h |
diff --git a/base/files/file_descriptor_watcher_posix.h b/base/files/file_descriptor_watcher_posix.h |
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+++ b/base/files/file_descriptor_watcher_posix.h |
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+// Copyright 2016 The Chromium Authors. All rights reserved. |
+// Use of this source code is governed by a BSD-style license that can be |
+// found in the LICENSE file. |
+ |
+#ifndef BASE_FILES_FILE_DESCRIPTOR_WATCHER_POSIX_H_ |
+#define BASE_FILES_FILE_DESCRIPTOR_WATCHER_POSIX_H_ |
+ |
+#include <memory> |
+ |
+#include "base/base_export.h" |
+#include "base/callback.h" |
+#include "base/macros.h" |
+#include "base/memory/ref_counted.h" |
+#include "base/memory/weak_ptr.h" |
+#include "base/message_loop/message_loop.h" |
+#include "base/sequence_checker.h" |
+ |
+namespace base { |
+ |
+class SingleThreadTaskRunner; |
+ |
+// The FileDescriptorWatcher API allows callbacks to be invoked when file |
+// descriptors are readable or writable without blocking. |
+class BASE_EXPORT FileDescriptorWatcher { |
+ public: |
+ // Instantiated and returned by WatchReadable() or WatchWritable(). The |
+ // constructor registers a callback to be invoked when a file descriptor is |
+ // readable or writable without blocking and the destructor unregisters it. |
+ class Controller { |
+ public: |
+ // Unregisters the callback registered by the constructor. |
+ ~Controller(); |
+ |
+ private: |
+ friend class FileDescriptorWatcher; |
+ class Watcher; |
+ |
+ // Registers |callback| to be invoked when |fd| is readable or writable |
+ // without blocking (depending on |mode|). |
+ Controller(MessageLoopForIO::Mode mode, int fd, const Closure& callback); |
+ |
+ // Starts watching the file descriptor. |
+ void StartWatching(); |
+ |
+ // Runs |callback_|. |
+ void RunCallback(); |
+ |
+ // The callback to run when the watched file descriptor is readable or |
+ // writable without blocking. |
+ Closure callback_; |
+ |
+ // TaskRunner associated with the MessageLoopForIO that watches the file |
+ // descriptor. |
+ const scoped_refptr<SingleThreadTaskRunner> |
+ message_loop_for_io_task_runner_; |
+ |
+ // Notified by the MessageLoopForIO associated with |
+ // |message_loop_for_io_task_runner_| when the watched file descriptor is |
+ // readable or writable without blocking. Posts a task to run RunCallback() |
+ // on the sequence on which the Controller was instantiated. When the |
+ // Controller is deleted, ownership of |watcher_| is transfered to a delete |
+ // task posted to the MessageLoopForIO. This ensures that |watcher_| isn't |
+ // deleted while it is being used by the MessageLoopForIO. |
+ std::unique_ptr<Watcher> watcher_; |
+ |
+ // Validates that the Controller is used on the sequence on which it was |
+ // instantiated. |
+ SequenceChecker sequence_checker_; |
+ |
+ WeakPtrFactory<Controller> weak_factory_; |
+ |
+ DISALLOW_COPY_AND_ASSIGN(Controller); |
+ }; |
+ |
+ // Registers |message_loop_for_io| to watch file descriptors for which |
+ // callbacks are registered from the current thread via WatchReadable() or |
+ // WatchWritable(). |message_loop_for_io| may run on another thread. The |
+ // constructed FileDescriptorWatcher must not outlive |message_loop_for_io|. |
+ FileDescriptorWatcher(MessageLoopForIO* message_loop_for_io); |
+ ~FileDescriptorWatcher(); |
+ |
+ // Registers |callback| to be invoked on the current sequence when |fd| is |
+ // readable or writable without blocking. |callback| is unregistered when the |
+ // returned Controller is deleted (deletion must happen on the current |
+ // sequence). To call these methods, a FileDescriptorWatcher must have been |
+ // instantiated on the current thread and SequencedTaskRunnerHandle::IsSet() |
+ // must return true. |
+ static std::unique_ptr<Controller> WatchReadable(int fd, |
+ const Closure& callback); |
+ static std::unique_ptr<Controller> WatchWritable(int fd, |
+ const Closure& callback); |
+ |
+ private: |
+ DISALLOW_COPY_AND_ASSIGN(FileDescriptorWatcher); |
+}; |
+ |
+} // namespace base |
+ |
+#endif // BASE_FILES_FILE_DESCRIPTOR_WATCHER_POSIX_H_ |