1 files changed, 304 insertions, 0 deletions
diff --git a/services/surfaceflinger/TransactionCompletedThread.cpp b/services/surfaceflinger/TransactionCompletedThread.cpp
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+++ b/services/surfaceflinger/TransactionCompletedThread.cpp
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+/*
+ * Copyright 2018 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.
+ */
+
+//#define LOG_NDEBUG 0
+#undef LOG_TAG
+#define LOG_TAG "TransactionCompletedThread"
+#define ATRACE_TAG ATRACE_TAG_GRAPHICS
+
+#include "TransactionCompletedThread.h"
+
+#include <cinttypes>
+
+#include <binder/IInterface.h>
+#include <gui/ITransactionCompletedListener.h>
+#include <utils/RefBase.h>
+
+namespace android {
+
+// Returns 0 if they are equal
+//         <0 if the first id that doesn't match is lower in c2 or all ids match but c2 is shorter
+//         >0 if the first id that doesn't match is greater in c2 or all ids match but c2 is longer
+//
+// See CallbackIdsHash for a explaniation of why this works
+static int compareCallbackIds(const std::vector<CallbackId>& c1,
+                              const std::vector<CallbackId>& c2) {
+    if (c1.empty()) {
+        return !c2.empty();
+    }
+    return c1.front() - c2.front();
+}
+
+TransactionCompletedThread::~TransactionCompletedThread() {
+    std::lock_guard lockThread(mThreadMutex);
+
+    {
+        std::lock_guard lock(mMutex);
+        mKeepRunning = false;
+        mConditionVariable.notify_all();
+    }
+
+    if (mThread.joinable()) {
+        mThread.join();
+    }
+
+    {
+        std::lock_guard lock(mMutex);
+        for (const auto& [listener, transactionStats] : mCompletedTransactions) {
+            IInterface::asBinder(listener)->unlinkToDeath(mDeathRecipient);
+        }
+    }
+}
+
+void TransactionCompletedThread::run() {
+    std::lock_guard lock(mMutex);
+    if (mRunning || !mKeepRunning) {
+        return;
+    }
+    mDeathRecipient = new ThreadDeathRecipient();
+    mRunning = true;
+
+    std::lock_guard lockThread(mThreadMutex);
+    mThread = std::thread(&TransactionCompletedThread::threadMain, this);
+}
+
+status_t TransactionCompletedThread::addCallback(const sp<ITransactionCompletedListener>& listener,
+                                                 const std::vector<CallbackId>& callbackIds) {
+    std::lock_guard lock(mMutex);
+    if (!mRunning) {
+        ALOGE("cannot add callback because the callback thread isn't running");
+        return BAD_VALUE;
+    }
+
+    if (mCompletedTransactions.count(listener) == 0) {
+        status_t err = IInterface::asBinder(listener)->linkToDeath(mDeathRecipient);
+        if (err != NO_ERROR) {
+            ALOGE("cannot add callback because linkToDeath failed, err: %d", err);
+            return err;
+        }
+    }
+
+    auto& transactionStatsDeque = mCompletedTransactions[listener];
+    transactionStatsDeque.emplace_back(callbackIds);
+    return NO_ERROR;
+}
+
+status_t TransactionCompletedThread::registerPendingCallbackHandle(
+        const sp<CallbackHandle>& handle) {
+    std::lock_guard lock(mMutex);
+    if (!mRunning) {
+        ALOGE("cannot register callback handle because the callback thread isn't running");
+        return BAD_VALUE;
+    }
+
+    // If we can't find the transaction stats something has gone wrong. The client should call
+    // addCallback before trying to register a pending callback handle.
+    TransactionStats* transactionStats;
+    status_t err = findTransactionStats(handle->listener, handle->callbackIds, &transactionStats);
+    if (err != NO_ERROR) {
+        ALOGE("cannot find transaction stats");
+        return err;
+    }
+
+    mPendingTransactions[handle->listener][handle->callbackIds]++;
+    return NO_ERROR;
+}
+
+status_t TransactionCompletedThread::addPresentedCallbackHandles(
+        const std::deque<sp<CallbackHandle>>& handles) {
+    std::lock_guard lock(mMutex);
+    if (!mRunning) {
+        ALOGE("cannot add presented callback handle because the callback thread isn't running");
+        return BAD_VALUE;
+    }
+
+    for (const auto& handle : handles) {
+        auto listener = mPendingTransactions.find(handle->listener);
+        if (listener != mPendingTransactions.end()) {
+            auto& pendingCallbacks = listener->second;
+            auto pendingCallback = pendingCallbacks.find(handle->callbackIds);
+
+            if (pendingCallback != pendingCallbacks.end()) {
+                auto& pendingCount = pendingCallback->second;
+
+                // Decrease the pending count for this listener
+                if (--pendingCount == 0) {
+                    pendingCallbacks.erase(pendingCallback);
+                }
+            } else {
+                ALOGW("there are more latched callbacks than there were registered callbacks");
+            }
+            if (listener->second.size() == 0) {
+                mPendingTransactions.erase(listener);
+            }
+        } else {
+            ALOGW("cannot find listener in mPendingTransactions");
+        }
+
+        status_t err = addCallbackHandle(handle);
+        if (err != NO_ERROR) {
+            ALOGE("could not add callback handle");
+            return err;
+        }
+    }
+
+    return NO_ERROR;
+}
+
+status_t TransactionCompletedThread::addUnpresentedCallbackHandle(
+        const sp<CallbackHandle>& handle) {
+    std::lock_guard lock(mMutex);
+    if (!mRunning) {
+        ALOGE("cannot add unpresented callback handle because the callback thread isn't running");
+        return BAD_VALUE;
+    }
+
+    return addCallbackHandle(handle);
+}
+
+status_t TransactionCompletedThread::findTransactionStats(
+        const sp<ITransactionCompletedListener>& listener,
+        const std::vector<CallbackId>& callbackIds, TransactionStats** outTransactionStats) {
+    auto& transactionStatsDeque = mCompletedTransactions[listener];
+
+    // Search back to front because the most recent transactions are at the back of the deque
+    auto itr = transactionStatsDeque.rbegin();
+    for (; itr != transactionStatsDeque.rend(); itr++) {
+        if (compareCallbackIds(itr->callbackIds, callbackIds) == 0) {
+            *outTransactionStats = &(*itr);
+            return NO_ERROR;
+        }
+    }
+
+    ALOGE("could not find transaction stats");
+    return BAD_VALUE;
+}
+
+status_t TransactionCompletedThread::addCallbackHandle(const sp<CallbackHandle>& handle) {
+    // If we can't find the transaction stats something has gone wrong. The client should call
+    // addCallback before trying to add a presnted callback handle.
+    TransactionStats* transactionStats;
+    status_t err = findTransactionStats(handle->listener, handle->callbackIds, &transactionStats);
+    if (err != NO_ERROR) {
+        return err;
+    }
+
+    transactionStats->latchTime = handle->latchTime;
+    // If the layer has already been destroyed, don't add the SurfaceControl to the callback.
+    // The client side keeps a sp<> to the SurfaceControl so if the SurfaceControl has been
+    // destroyed the client side is dead and there won't be anyone to send the callback to.
+    sp<IBinder> surfaceControl = handle->surfaceControl.promote();
+    if (surfaceControl) {
+        transactionStats->surfaceStats.emplace_back(surfaceControl, handle->acquireTime,
+                                                    handle->previousReleaseFence);
+    }
+    return NO_ERROR;
+}
+
+void TransactionCompletedThread::addPresentFence(const sp<Fence>& presentFence) {
+    std::lock_guard<std::mutex> lock(mMutex);
+    mPresentFence = presentFence;
+}
+
+void TransactionCompletedThread::sendCallbacks() {
+    std::lock_guard lock(mMutex);
+    if (mRunning) {
+        mConditionVariable.notify_all();
+    }
+}
+
+void TransactionCompletedThread::threadMain() {
+    std::lock_guard lock(mMutex);
+
+    while (mKeepRunning) {
+        mConditionVariable.wait(mMutex);
+        std::vector<ListenerStats> completedListenerStats;
+
+        // For each listener
+        auto completedTransactionsItr = mCompletedTransactions.begin();
+        while (completedTransactionsItr != mCompletedTransactions.end()) {
+            auto& [listener, transactionStatsDeque] = *completedTransactionsItr;
+            ListenerStats listenerStats;
+            listenerStats.listener = listener;
+
+            // For each transaction
+            auto transactionStatsItr = transactionStatsDeque.begin();
+            while (transactionStatsItr != transactionStatsDeque.end()) {
+                auto& transactionStats = *transactionStatsItr;
+
+                // If we are still waiting on the callback handles for this transaction, stop
+                // here because all transaction callbacks for the same listener must come in order
+                auto pendingTransactions = mPendingTransactions.find(listener);
+                if (pendingTransactions != mPendingTransactions.end() &&
+                    pendingTransactions->second.count(transactionStats.callbackIds) != 0) {
+                    break;
+                }
+
+                // If the transaction has been latched
+                if (transactionStats.latchTime >= 0) {
+                    if (!mPresentFence) {
+                        break;
+                    }
+                    transactionStats.presentFence = mPresentFence;
+                }
+
+                // Remove the transaction from completed to the callback
+                listenerStats.transactionStats.push_back(std::move(transactionStats));
+                transactionStatsItr = transactionStatsDeque.erase(transactionStatsItr);
+            }
+            // If the listener has completed transactions
+            if (!listenerStats.transactionStats.empty()) {
+                // If the listener is still alive
+                if (IInterface::asBinder(listener)->isBinderAlive()) {
+                    // Send callback
+                    listenerStats.listener->onTransactionCompleted(listenerStats);
+                    IInterface::asBinder(listener)->unlinkToDeath(mDeathRecipient);
+                }
+                completedTransactionsItr = mCompletedTransactions.erase(completedTransactionsItr);
+            } else {
+                completedTransactionsItr++;
+            }
+
+            completedListenerStats.push_back(std::move(listenerStats));
+        }
+
+        if (mPresentFence) {
+            mPresentFence.clear();
+        }
+
+        // If everyone else has dropped their reference to a layer and its listener is dead,
+        // we are about to cause the layer to be deleted. If this happens at the wrong time and
+        // we are holding mMutex, we will cause a deadlock.
+        //
+        // The deadlock happens because this thread is holding on to mMutex and when we delete
+        // the layer, it grabs SF's mStateLock. A different SF binder thread grabs mStateLock,
+        // then call's TransactionCompletedThread::run() which tries to grab mMutex.
+        //
+        // To avoid this deadlock, we need to unlock mMutex when dropping our last reference to
+        // to the layer.
+        mMutex.unlock();
+        completedListenerStats.clear();
+        mMutex.lock();
+    }
+}
+
+// -----------------------------------------------------------------------
+
+CallbackHandle::CallbackHandle(const sp<ITransactionCompletedListener>& transactionListener,
+                               const std::vector<CallbackId>& ids, const sp<IBinder>& sc)
+      : listener(transactionListener), callbackIds(ids), surfaceControl(sc) {}
+
+} // namespace android