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Diffstat (limited to 'include/utils/PollLoop.h')
| -rw-r--r-- | include/utils/PollLoop.h | 219 |
1 files changed, 0 insertions, 219 deletions
diff --git a/include/utils/PollLoop.h b/include/utils/PollLoop.h deleted file mode 100644 index c2dfe5d..0000000 --- a/include/utils/PollLoop.h +++ /dev/null @@ -1,219 +0,0 @@ -/* - * Copyright (C) 2010 The Android Open Source Project - * - * Licensed under the Apache License, Version 2.0 (the "License"); - * you may not use this file except in compliance with the License. - * You may obtain a copy of the License at - * - * http://www.apache.org/licenses/LICENSE-2.0 - * - * Unless required by applicable law or agreed to in writing, software - * distributed under the License is distributed on an "AS IS" BASIS, - * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - * See the License for the specific language governing permissions and - * limitations under the License. - */ - -#ifndef UTILS_POLL_LOOP_H -#define UTILS_POLL_LOOP_H - -#include <utils/Vector.h> -#include <utils/threads.h> - -#include <sys/poll.h> - -#include <android/looper.h> - -struct ALooper : public android::RefBase { -protected: - virtual ~ALooper() { } - -public: - ALooper() { } -}; - -namespace android { - -/** - * A basic file descriptor polling loop based on poll() with callbacks. - */ -class PollLoop : public ALooper { -protected: - virtual ~PollLoop(); - -public: - PollLoop(bool allowNonCallbacks); - - /** - * A callback that it to be invoked when an event occurs on a file descriptor. - * Specifies the events that were triggered and the user data provided when the - * callback was set. - * - * Returns true if the callback should be kept, false if it should be removed automatically - * after the callback returns. - */ - typedef bool (*Callback)(int fd, int events, void* data); - - enum { - POLL_CALLBACK = ALOOPER_POLL_CALLBACK, - POLL_TIMEOUT = ALOOPER_POLL_TIMEOUT, - POLL_ERROR = ALOOPER_POLL_ERROR, - }; - - /** - * Performs a single call to poll() with optional timeout in milliseconds. - * Invokes callbacks for all file descriptors on which an event occurred. - * - * If the timeout is zero, returns immediately without blocking. - * If the timeout is negative, waits indefinitely until awoken. - * - * Returns ALOOPER_POLL_CALLBACK if a callback was invoked. - * - * Returns ALOOPER_POLL_TIMEOUT if there was no data before the given - * timeout expired. - * - * Returns ALOPER_POLL_ERROR if an error occurred. - * - * Returns a value >= 0 containing a file descriptor if it has data - * and it has no callback function (requiring the caller here to handle it). - * In this (and only this) case outEvents and outData will contain the poll - * events and data associated with the fd. - * - * This method must only be called on the thread owning the PollLoop. - * This method blocks until either a file descriptor is signalled, a timeout occurs, - * or wake() is called. - * This method does not return until it has finished invoking the appropriate callbacks - * for all file descriptors that were signalled. - */ - int32_t pollOnce(int timeoutMillis, int* outEvents = NULL, void** outData = NULL); - - /** - * Wakes the loop asynchronously. - * - * This method can be called on any thread. - * This method returns immediately. - */ - void wake(); - - /** - * Control whether this PollLoop instance allows using IDs instead - * of callbacks. - */ - bool getAllowNonCallbacks() const; - - /** - * Sets the callback for a file descriptor, replacing the existing one, if any. - * It is an error to call this method with events == 0 or callback == NULL. - * - * Note that a callback can be invoked with the POLLERR, POLLHUP or POLLNVAL events - * even if it is not explicitly requested when registered. - * - * This method can be called on any thread. - * This method may block briefly if it needs to wake the poll loop. - */ - void setCallback(int fd, int ident, int events, Callback callback, void* data = NULL); - - /** - * Convenience for above setCallback when ident is not used. In this case - * the ident is set to POLL_CALLBACK. - */ - void setCallback(int fd, int events, Callback callback, void* data = NULL); - - /** - * Like setCallback(), but for the NDK callback function. - */ - void setLooperCallback(int fd, int ident, int events, ALooper_callbackFunc* callback, - void* data); - - /** - * Removes the callback for a file descriptor, if one exists. - * - * When this method returns, it is safe to close the file descriptor since the poll loop - * will no longer have a reference to it. However, it is possible for the callback to - * already be running or for it to run one last time if the file descriptor was already - * signalled. Calling code is responsible for ensuring that this case is safely handled. - * For example, if the callback takes care of removing itself during its own execution either - * by returning false or calling this method, then it can be guaranteed to not be invoked - * again at any later time unless registered anew. - * - * This method can be called on any thread. - * This method may block briefly if it needs to wake the poll loop. - * - * Returns true if a callback was actually removed, false if none was registered. - */ - bool removeCallback(int fd); - - /** - * Set the given PollLoop to be associated with the - * calling thread. There must be a 1:1 relationship between - * PollLoop and thread. - */ - static void setForThread(const sp<PollLoop>& pollLoop); - - /** - * Return the PollLoop associated with the calling thread. - */ - static sp<PollLoop> getForThread(); - -private: - struct RequestedCallback { - Callback callback; - ALooper_callbackFunc* looperCallback; - int ident; - void* data; - }; - - struct PendingCallback { - int fd; - int ident; - int events; - Callback callback; - ALooper_callbackFunc* looperCallback; - void* data; - }; - - const bool mAllowNonCallbacks; // immutable - - int mWakeReadPipeFd; // immutable - int mWakeWritePipeFd; // immutable - - // The lock guards state used to track whether there is a poll() in progress and whether - // there are any other threads waiting in wakeAndLock(). The condition variables - // are used to transfer control among these threads such that all waiters are - // serviced before a new poll can begin. - // The wakeAndLock() method increments mWaiters, wakes the poll, blocks on mAwake - // until mPolling becomes false, then decrements mWaiters again. - // The poll() method blocks on mResume until mWaiters becomes 0, then sets - // mPolling to true, blocks until the poll completes, then resets mPolling to false - // and signals mResume if there are waiters. - Mutex mLock; - bool mPolling; // guarded by mLock - uint32_t mWaiters; // guarded by mLock - Condition mAwake; // guarded by mLock - Condition mResume; // guarded by mLock - - // The next two vectors are only mutated when mPolling is false since they must - // not be changed while the poll() system call is in progress. To mutate these - // vectors, the poll() must first be awoken then the lock acquired. - Vector<struct pollfd> mRequestedFds; - Vector<RequestedCallback> mRequestedCallbacks; - - // This state is only used privately by pollOnce and does not require a lock since - // it runs on a single thread. - Vector<PendingCallback> mPendingCallbacks; - Vector<PendingCallback> mPendingFds; - size_t mPendingFdsPos; - - void openWakePipe(); - void closeWakePipe(); - - void setCallbackCommon(int fd, int ident, int events, Callback callback, - ALooper_callbackFunc* looperCallback, void* data); - ssize_t getRequestIndexLocked(int fd); - void wakeAndLock(); - static void threadDestructor(void *st); -}; - -} // namespace android - -#endif // UTILS_POLL_LOOP_H |