1 files changed, 573 insertions, 0 deletions

diff --git a/libshims/utils/Looper.cpp b/libshims/utils/Looper.cpp
new file mode 100644
index 0000000..4bab6d5
--- /dev/null
+++ b/libshims/utils/Looper.cpp
@@ -0,0 +1,573 @@
+//
+// Copyright 2010 The Android Open Source Project
+//
+// A looper implementation based on epoll().
+//
+#define LOG_TAG "Looper"
+
+//#define LOG_NDEBUG 0
+
+// Debugs poll and wake interactions.
+#define DEBUG_POLL_AND_WAKE 0
+
+// Debugs callback registration and invocation.
+#define DEBUG_CALLBACKS 0
+
+#include <cutils/log.h>
+#include <utils/Looper.h>
+#include <utils/Timers.h>
+
+#include <unistd.h>
+#include <fcntl.h>
+#include <limits.h>
+
+
+namespace android {
+
+// --- WeakMessageHandler ---
+
+WeakMessageHandler::WeakMessageHandler(const wp<MessageHandler>& handler) :
+        mHandler(handler) {
+}
+
+WeakMessageHandler::~WeakMessageHandler() {
+}
+
+void WeakMessageHandler::handleMessage(const Message& message) {
+    sp<MessageHandler> handler = mHandler.promote();
+    if (handler != NULL) {
+        handler->handleMessage(message);
+    }
+}
+
+
+// --- SimpleLooperCallback ---
+
+SimpleLooperCallback::SimpleLooperCallback(Looper_callbackFunc callback) :
+        mCallback(callback) {
+}
+
+SimpleLooperCallback::~SimpleLooperCallback() {
+}
+
+int SimpleLooperCallback::handleEvent(int fd, int events, void* data) {
+    return mCallback(fd, events, data);
+}
+
+
+// --- Looper ---
+
+// Hint for number of file descriptors to be associated with the epoll instance.
+static const int EPOLL_SIZE_HINT = 8;
+
+// Maximum number of file descriptors for which to retrieve poll events each iteration.
+static const int EPOLL_MAX_EVENTS = 16;
+
+static pthread_once_t gTLSOnce = PTHREAD_ONCE_INIT;
+static pthread_key_t gTLSKey = 0;
+
+Looper::Looper(bool allowNonCallbacks) :
+        mAllowNonCallbacks(allowNonCallbacks), mSendingMessage(false),
+        mResponseIndex(0), mNextMessageUptime(LLONG_MAX) {
+    int wakeFds[2];
+    int result = pipe(wakeFds);
+    LOG_ALWAYS_FATAL_IF(result != 0, "Could not create wake pipe.  errno=%d", errno);
+
+    mWakeReadPipeFd = wakeFds[0];
+    mWakeWritePipeFd = wakeFds[1];
+
+    result = fcntl(mWakeReadPipeFd, F_SETFL, O_NONBLOCK);
+    LOG_ALWAYS_FATAL_IF(result != 0, "Could not make wake read pipe non-blocking.  errno=%d",
+            errno);
+
+    result = fcntl(mWakeWritePipeFd, F_SETFL, O_NONBLOCK);
+    LOG_ALWAYS_FATAL_IF(result != 0, "Could not make wake write pipe non-blocking.  errno=%d",
+            errno);
+
+    mPolling = false;
+
+    // Allocate the epoll instance and register the wake pipe.
+    mEpollFd = epoll_create(EPOLL_SIZE_HINT);
+    LOG_ALWAYS_FATAL_IF(mEpollFd < 0, "Could not create epoll instance.  errno=%d", errno);
+
+    struct epoll_event eventItem;
+    memset(& eventItem, 0, sizeof(epoll_event)); // zero out unused members of data field union
+    eventItem.events = EPOLLIN;
+    eventItem.data.fd = mWakeReadPipeFd;
+    result = epoll_ctl(mEpollFd, EPOLL_CTL_ADD, mWakeReadPipeFd, & eventItem);
+    LOG_ALWAYS_FATAL_IF(result != 0, "Could not add wake read pipe to epoll instance.  errno=%d",
+            errno);
+}
+
+Looper::~Looper() {
+    close(mWakeReadPipeFd);
+    close(mWakeWritePipeFd);
+    close(mEpollFd);
+}
+
+void Looper::initTLSKey() {
+    int result = pthread_key_create(& gTLSKey, threadDestructor);
+    LOG_ALWAYS_FATAL_IF(result != 0, "Could not allocate TLS key.");
+}
+
+void Looper::threadDestructor(void *st) {
+    Looper* const self = static_cast<Looper*>(st);
+    if (self != NULL) {
+        self->decStrong((void*)threadDestructor);
+    }
+}
+
+void Looper::setForThread(const sp<Looper>& looper) {
+    sp<Looper> old = getForThread(); // also has side-effect of initializing TLS
+
+    if (looper != NULL) {
+        looper->incStrong((void*)threadDestructor);
+    }
+
+    pthread_setspecific(gTLSKey, looper.get());
+
+    if (old != NULL) {
+        old->decStrong((void*)threadDestructor);
+    }
+}
+
+sp<Looper> Looper::getForThread() {
+    int result = pthread_once(& gTLSOnce, initTLSKey);
+    LOG_ALWAYS_FATAL_IF(result != 0, "pthread_once failed");
+
+    return (Looper*)pthread_getspecific(gTLSKey);
+}
+
+sp<Looper> Looper::prepare(int opts) {
+    bool allowNonCallbacks = opts & PREPARE_ALLOW_NON_CALLBACKS;
+    sp<Looper> looper = Looper::getForThread();
+    if (looper == NULL) {
+        looper = new Looper(allowNonCallbacks);
+        Looper::setForThread(looper);
+    }
+    if (looper->getAllowNonCallbacks() != allowNonCallbacks) {
+        ALOGW("Looper already prepared for this thread with a different value for the "
+                "LOOPER_PREPARE_ALLOW_NON_CALLBACKS option.");
+    }
+    return looper;
+}
+
+bool Looper::getAllowNonCallbacks() const {
+    return mAllowNonCallbacks;
+}
+
+int Looper::pollOnce(int timeoutMillis, int* outFd, int* outEvents, void** outData) {
+    int result = 0;
+    for (;;) {
+        while (mResponseIndex < mResponses.size()) {
+            const Response& response = mResponses.itemAt(mResponseIndex++);
+            int ident = response.request.ident;
+            if (ident >= 0) {
+                int fd = response.request.fd;
+                int events = response.events;
+                void* data = response.request.data;
+#if DEBUG_POLL_AND_WAKE
+                ALOGD("%p ~ pollOnce - returning signalled identifier %d: "
+                        "fd=%d, events=0x%x, data=%p",
+                        this, ident, fd, events, data);
+#endif
+                if (outFd != NULL) *outFd = fd;
+                if (outEvents != NULL) *outEvents = events;
+                if (outData != NULL) *outData = data;
+                return ident;
+            }
+        }
+
+        if (result != 0) {
+#if DEBUG_POLL_AND_WAKE
+            ALOGD("%p ~ pollOnce - returning result %d", this, result);
+#endif
+            if (outFd != NULL) *outFd = 0;
+            if (outEvents != NULL) *outEvents = 0;
+            if (outData != NULL) *outData = NULL;
+            return result;
+        }
+
+        result = pollInner(timeoutMillis);
+    }
+}
+
+int Looper::pollInner(int timeoutMillis) {
+#if DEBUG_POLL_AND_WAKE
+    ALOGD("%p ~ pollOnce - waiting: timeoutMillis=%d", this, timeoutMillis);
+#endif
+
+    // Adjust the timeout based on when the next message is due.
+    if (timeoutMillis != 0 && mNextMessageUptime != LLONG_MAX) {
+        nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
+        int messageTimeoutMillis = toMillisecondTimeoutDelay(now, mNextMessageUptime);
+        if (messageTimeoutMillis >= 0
+                && (timeoutMillis < 0 || messageTimeoutMillis < timeoutMillis)) {
+            timeoutMillis = messageTimeoutMillis;
+        }
+#if DEBUG_POLL_AND_WAKE
+        ALOGD("%p ~ pollOnce - next message in %lldns, adjusted timeout: timeoutMillis=%d",
+                this, mNextMessageUptime - now, timeoutMillis);
+#endif
+    }
+
+    // Poll.
+    int result = POLL_WAKE;
+    mResponses.clear();
+    mResponseIndex = 0;
+
+    // We are about to idle.
+    mPolling = true;
+
+    struct epoll_event eventItems[EPOLL_MAX_EVENTS];
+    int eventCount = epoll_wait(mEpollFd, eventItems, EPOLL_MAX_EVENTS, timeoutMillis);
+
+    // No longer idling.
+    mPolling = false;
+
+    // Acquire lock.
+    mLock.lock();
+
+    // Check for poll error.
+    if (eventCount < 0) {
+        if (errno == EINTR) {
+            goto Done;
+        }
+        ALOGW("Poll failed with an unexpected error, errno=%d", errno);
+        result = POLL_ERROR;
+        goto Done;
+    }
+
+    // Check for poll timeout.
+    if (eventCount == 0) {
+#if DEBUG_POLL_AND_WAKE
+        ALOGD("%p ~ pollOnce - timeout", this);
+#endif
+        result = POLL_TIMEOUT;
+        goto Done;
+    }
+
+    // Handle all events.
+#if DEBUG_POLL_AND_WAKE
+    ALOGD("%p ~ pollOnce - handling events from %d fds", this, eventCount);
+#endif
+
+    for (int i = 0; i < eventCount; i++) {
+        int fd = eventItems[i].data.fd;
+        uint32_t epollEvents = eventItems[i].events;
+        if (fd == mWakeReadPipeFd) {
+            if (epollEvents & EPOLLIN) {
+                awoken();
+            } else {
+                ALOGW("Ignoring unexpected epoll events 0x%x on wake read pipe.", epollEvents);
+            }
+        } else {
+            ssize_t requestIndex = mRequests.indexOfKey(fd);
+            if (requestIndex >= 0) {
+                int events = 0;
+                if (epollEvents & EPOLLIN) events |= EVENT_INPUT;
+                if (epollEvents & EPOLLOUT) events |= EVENT_OUTPUT;
+                if (epollEvents & EPOLLERR) events |= EVENT_ERROR;
+                if (epollEvents & EPOLLHUP) events |= EVENT_HANGUP;
+                pushResponse(events, mRequests.valueAt(requestIndex));
+            } else {
+                ALOGW("Ignoring unexpected epoll events 0x%x on fd %d that is "
+                        "no longer registered.", epollEvents, fd);
+            }
+        }
+    }
+Done: ;
+
+    // Invoke pending message callbacks.
+    mNextMessageUptime = LLONG_MAX;
+    while (mMessageEnvelopes.size() != 0) {
+        nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
+        const MessageEnvelope& messageEnvelope = mMessageEnvelopes.itemAt(0);
+        if (messageEnvelope.uptime <= now) {
+            // Remove the envelope from the list.
+            // We keep a strong reference to the handler until the call to handleMessage
+            // finishes.  Then we drop it so that the handler can be deleted *before*
+            // we reacquire our lock.
+            { // obtain handler
+                sp<MessageHandler> handler = messageEnvelope.handler;
+                Message message = messageEnvelope.message;
+                mMessageEnvelopes.removeAt(0);
+                mSendingMessage = true;
+                mLock.unlock();
+
+#if DEBUG_POLL_AND_WAKE || DEBUG_CALLBACKS
+                ALOGD("%p ~ pollOnce - sending message: handler=%p, what=%d",
+                        this, handler.get(), message.what);
+#endif
+                handler->handleMessage(message);
+            } // release handler
+
+            mLock.lock();
+            mSendingMessage = false;
+            result = POLL_CALLBACK;
+        } else {
+            // The last message left at the head of the queue determines the next wakeup time.
+            mNextMessageUptime = messageEnvelope.uptime;
+            break;
+        }
+    }
+
+    // Release lock.
+    mLock.unlock();
+
+    // Invoke all response callbacks.
+    for (size_t i = 0; i < mResponses.size(); i++) {
+        Response& response = mResponses.editItemAt(i);
+        if (response.request.ident == POLL_CALLBACK) {
+            int fd = response.request.fd;
+            int events = response.events;
+            void* data = response.request.data;
+#if DEBUG_POLL_AND_WAKE || DEBUG_CALLBACKS
+            ALOGD("%p ~ pollOnce - invoking fd event callback %p: fd=%d, events=0x%x, data=%p",
+                    this, response.request.callback.get(), fd, events, data);
+#endif
+            int callbackResult = response.request.callback->handleEvent(fd, events, data);
+            if (callbackResult == 0) {
+                removeFd(fd);
+            }
+            // Clear the callback reference in the response structure promptly because we
+            // will not clear the response vector itself until the next poll.
+            response.request.callback.clear();
+            result = POLL_CALLBACK;
+        }
+    }
+    return result;
+}
+
+int Looper::pollAll(int timeoutMillis, int* outFd, int* outEvents, void** outData) {
+    if (timeoutMillis <= 0) {
+        int result;
+        do {
+            result = pollOnce(timeoutMillis, outFd, outEvents, outData);
+        } while (result == POLL_CALLBACK);
+        return result;
+    } else {
+        nsecs_t endTime = systemTime(SYSTEM_TIME_MONOTONIC)
+                + milliseconds_to_nanoseconds(timeoutMillis);
+
+        for (;;) {
+            int result = pollOnce(timeoutMillis, outFd, outEvents, outData);
+            if (result != POLL_CALLBACK) {
+                return result;
+            }
+
+            nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
+            timeoutMillis = toMillisecondTimeoutDelay(now, endTime);
+            if (timeoutMillis == 0) {
+                return POLL_TIMEOUT;
+            }
+        }
+    }
+}
+
+void Looper::wake() {
+#if DEBUG_POLL_AND_WAKE
+    ALOGD("%p ~ wake", this);
+#endif
+
+    ssize_t nWrite;
+    do {
+        nWrite = write(mWakeWritePipeFd, "W", 1);
+    } while (nWrite == -1 && errno == EINTR);
+
+    if (nWrite != 1) {
+        if (errno != EAGAIN) {
+            ALOGW("Could not write wake signal, errno=%d", errno);
+        }
+    }
+}
+
+void Looper::awoken() {
+#if DEBUG_POLL_AND_WAKE
+    ALOGD("%p ~ awoken", this);
+#endif
+
+    char buffer[16];
+    ssize_t nRead;
+    do {
+        nRead = read(mWakeReadPipeFd, buffer, sizeof(buffer));
+    } while ((nRead == -1 && errno == EINTR) || nRead == sizeof(buffer));
+}
+
+void Looper::pushResponse(int events, const Request& request) {
+    Response response;
+    response.events = events;
+    response.request = request;
+    mResponses.push(response);
+}
+
+int Looper::addFd(int fd, int ident, int events, Looper_callbackFunc callback, void* data) {
+    return addFd(fd, ident, events, callback ? new SimpleLooperCallback(callback) : NULL, data);
+}
+
+int Looper::addFd(int fd, int ident, int events, const sp<LooperCallback>& callback, void* data) {
+#if DEBUG_CALLBACKS
+    ALOGD("%p ~ addFd - fd=%d, ident=%d, events=0x%x, callback=%p, data=%p", this, fd, ident,
+            events, callback.get(), data);
+#endif
+
+    if (!callback.get()) {
+        if (! mAllowNonCallbacks) {
+            ALOGE("Invalid attempt to set NULL callback but not allowed for this looper.");
+            return -1;
+        }
+
+        if (ident < 0) {
+            ALOGE("Invalid attempt to set NULL callback with ident < 0.");
+            return -1;
+        }
+    } else {
+        ident = POLL_CALLBACK;
+    }
+
+    int epollEvents = 0;
+    if (events & EVENT_INPUT) epollEvents |= EPOLLIN;
+    if (events & EVENT_OUTPUT) epollEvents |= EPOLLOUT;
+
+    { // acquire lock
+        AutoMutex _l(mLock);
+
+        Request request;
+        request.fd = fd;
+        request.ident = ident;
+        request.callback = callback;
+        request.data = data;
+
+        struct epoll_event eventItem;
+        memset(& eventItem, 0, sizeof(epoll_event)); // zero out unused members of data field union
+        eventItem.events = epollEvents;
+        eventItem.data.fd = fd;
+
+        ssize_t requestIndex = mRequests.indexOfKey(fd);
+        if (requestIndex < 0) {
+            int epollResult = epoll_ctl(mEpollFd, EPOLL_CTL_ADD, fd, & eventItem);
+            if (epollResult < 0) {
+                ALOGE("Error adding epoll events for fd %d, errno=%d", fd, errno);
+                return -1;
+            }
+            mRequests.add(fd, request);
+        } else {
+            int epollResult = epoll_ctl(mEpollFd, EPOLL_CTL_MOD, fd, & eventItem);
+            if (epollResult < 0) {
+                ALOGE("Error modifying epoll events for fd %d, errno=%d", fd, errno);
+                return -1;
+            }
+            mRequests.replaceValueAt(requestIndex, request);
+        }
+    } // release lock
+    return 1;
+}
+
+int Looper::removeFd(int fd) {
+#if DEBUG_CALLBACKS
+    ALOGD("%p ~ removeFd - fd=%d", this, fd);
+#endif
+
+    { // acquire lock
+        AutoMutex _l(mLock);
+        ssize_t requestIndex = mRequests.indexOfKey(fd);
+        if (requestIndex < 0) {
+            return 0;
+        }
+
+        int epollResult = epoll_ctl(mEpollFd, EPOLL_CTL_DEL, fd, NULL);
+        if (epollResult < 0) {
+            ALOGE("Error removing epoll events for fd %d, errno=%d", fd, errno);
+            return -1;
+        }
+
+        mRequests.removeItemsAt(requestIndex);
+    } // release lock
+    return 1;
+}
+
+void Looper::sendMessage(const sp<MessageHandler>& handler, const Message& message) {
+    nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
+    sendMessageAtTime(now, handler, message);
+}
+
+void Looper::sendMessageDelayed(nsecs_t uptimeDelay, const sp<MessageHandler>& handler,
+        const Message& message) {
+    nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
+    sendMessageAtTime(now + uptimeDelay, handler, message);
+}
+
+void Looper::sendMessageAtTime(nsecs_t uptime, const sp<MessageHandler>& handler,
+        const Message& message) {
+#if DEBUG_CALLBACKS
+    ALOGD("%p ~ sendMessageAtTime - uptime=%lld, handler=%p, what=%d",
+            this, uptime, handler.get(), message.what);
+#endif
+
+    size_t i = 0;
+    { // acquire lock
+        AutoMutex _l(mLock);
+
+        size_t messageCount = mMessageEnvelopes.size();
+        while (i < messageCount && uptime >= mMessageEnvelopes.itemAt(i).uptime) {
+            i += 1;
+        }
+
+        MessageEnvelope messageEnvelope(uptime, handler, message);
+        mMessageEnvelopes.insertAt(messageEnvelope, i, 1);
+
+        // Optimization: If the Looper is currently sending a message, then we can skip
+        // the call to wake() because the next thing the Looper will do after processing
+        // messages is to decide when the next wakeup time should be.  In fact, it does
+        // not even matter whether this code is running on the Looper thread.
+        if (mSendingMessage) {
+            return;
+        }
+    } // release lock
+
+    // Wake the poll loop only when we enqueue a new message at the head.
+    if (i == 0) {
+        wake();
+    }
+}
+
+void Looper::removeMessages(const sp<MessageHandler>& handler) {
+#if DEBUG_CALLBACKS
+    ALOGD("%p ~ removeMessages - handler=%p", this, handler.get());
+#endif
+
+    { // acquire lock
+        AutoMutex _l(mLock);
+
+        for (size_t i = mMessageEnvelopes.size(); i != 0; ) {
+            const MessageEnvelope& messageEnvelope = mMessageEnvelopes.itemAt(--i);
+            if (messageEnvelope.handler == handler) {
+                mMessageEnvelopes.removeAt(i);
+            }
+        }
+    } // release lock
+}
+
+void Looper::removeMessages(const sp<MessageHandler>& handler, int what) {
+#if DEBUG_CALLBACKS
+    ALOGD("%p ~ removeMessages - handler=%p, what=%d", this, handler.get(), what);
+#endif
+
+    { // acquire lock
+        AutoMutex _l(mLock);
+
+        for (size_t i = mMessageEnvelopes.size(); i != 0; ) {
+            const MessageEnvelope& messageEnvelope = mMessageEnvelopes.itemAt(--i);
+            if (messageEnvelope.handler == handler
+                    && messageEnvelope.message.what == what) {
+                mMessageEnvelopes.removeAt(i);
+            }
+        }
+    } // release lock
+}
+
+bool Looper::isPolling() const {
+    return mPolling;
+}
+
+} // namespace android
\ No newline at end of file