libgui: Add dequeue/attach timeout

Adds the ability to specify the timeout when dequeueBuffer or
attachBuffer block due to the lack of a free buffer/slot. By default,
these will block indefinitely (which is signified by a timeout of -1).

When a timeout (other than -1) is specified, non-blocking mode is
disabled and the given timeout will be used instead.

Bug: 25196773
Change-Id: I17fdbeebccb7c8d878703d758ac1209608258e61
diff --git a/libs/gui/BufferQueueProducer.cpp b/libs/gui/BufferQueueProducer.cpp
index 9271ed8..c48f237 100644
--- a/libs/gui/BufferQueueProducer.cpp
+++ b/libs/gui/BufferQueueProducer.cpp
@@ -43,7 +43,8 @@
     mCallbackMutex(),
     mNextCallbackTicket(0),
     mCurrentCallbackTicket(0),
-    mCallbackCondition() {}
+    mCallbackCondition(),
+    mDequeueTimeout(-1) {}
 
 BufferQueueProducer::~BufferQueueProducer() {}
 
@@ -271,7 +272,15 @@
                     (acquiredCount <= mCore->mMaxAcquiredBufferCount)) {
                 return WOULD_BLOCK;
             }
-            mCore->mDequeueCondition.wait(mCore->mMutex);
+            if (mDequeueTimeout >= 0) {
+                status_t result = mCore->mDequeueCondition.waitRelative(
+                        mCore->mMutex, mDequeueTimeout);
+                if (result == TIMED_OUT) {
+                    return result;
+                }
+            } else {
+                mCore->mDequeueCondition.wait(mCore->mMutex);
+            }
         }
     } // while (tryAgain)
 
@@ -1012,8 +1021,11 @@
     }
 
     mCore->mBufferHasBeenQueued = false;
-    mCore->mDequeueBufferCannotBlock =  mCore->mConsumerControlledByApp &&
-            producerControlledByApp;
+    mCore->mDequeueBufferCannotBlock = false;
+    if (mDequeueTimeout < 0) {
+        mCore->mDequeueBufferCannotBlock =
+                mCore->mConsumerControlledByApp && producerControlledByApp;
+    }
     mCore->mAllowAllocation = true;
 
     return status;
@@ -1247,7 +1259,16 @@
         mCore->mSingleBufferSlot = BufferQueueCore::INVALID_BUFFER_SLOT;
     }
     mCore->mSingleBufferMode = singleBufferMode;
+    return NO_ERROR;
+}
 
+status_t BufferQueueProducer::setDequeueTimeout(nsecs_t timeout) {
+    ATRACE_CALL();
+    BQ_LOGV("setDequeueTimeout: %" PRId64, timeout);
+
+    Mutex::Autolock lock(mCore->mMutex);
+    mDequeueTimeout = timeout;
+    mCore->mDequeueBufferCannotBlock = false;
     return NO_ERROR;
 }
 
diff --git a/libs/gui/IGraphicBufferProducer.cpp b/libs/gui/IGraphicBufferProducer.cpp
index d5310bd..0cca58d 100644
--- a/libs/gui/IGraphicBufferProducer.cpp
+++ b/libs/gui/IGraphicBufferProducer.cpp
@@ -51,7 +51,8 @@
     SET_MAX_DEQUEUED_BUFFER_COUNT,
     SET_ASYNC_MODE,
     GET_NEXT_FRAME_NUMBER,
-    SET_SINGLE_BUFFER_MODE
+    SET_SINGLE_BUFFER_MODE,
+    SET_DEQUEUE_TIMEOUT,
 };
 
 class BpGraphicBufferProducer : public BpInterface<IGraphicBufferProducer>
@@ -353,6 +354,18 @@
         }
         return result;
     }
+
+    virtual status_t setDequeueTimeout(nsecs_t timeout) {
+        Parcel data, reply;
+        data.writeInterfaceToken(IGraphicBufferProducer::getInterfaceDescriptor());
+        data.writeInt64(timeout);
+        status_t result = remote()->transact(SET_DEQUEUE_TIMEOUT, data, &reply);
+        if (result != NO_ERROR) {
+            ALOGE("setDequeueTimeout failed to transact: %d", result);
+            return result;
+        }
+        return reply.readInt32();
+    }
 };
 
 // Out-of-line virtual method definition to trigger vtable emission in this
@@ -548,6 +561,13 @@
             reply->writeInt32(result);
             return NO_ERROR;
         }
+        case SET_DEQUEUE_TIMEOUT: {
+            CHECK_INTERFACE(IGraphicBufferProducer, data, reply);
+            nsecs_t timeout = data.readInt64();
+            status_t result = setDequeueTimeout(timeout);
+            reply->writeInt32(result);
+            return NO_ERROR;
+        }
     }
     return BBinder::onTransact(code, data, reply, flags);
 }
diff --git a/libs/gui/Surface.cpp b/libs/gui/Surface.cpp
index b816ff3..9e90ad0 100644
--- a/libs/gui/Surface.cpp
+++ b/libs/gui/Surface.cpp
@@ -119,6 +119,10 @@
     return mGraphicBufferProducer->getConsumerName();
 }
 
+status_t Surface::setDequeueTimeout(nsecs_t timeout) {
+    return mGraphicBufferProducer->setDequeueTimeout(timeout);
+}
+
 int Surface::hook_setSwapInterval(ANativeWindow* window, int interval) {
     Surface* c = getSelf(window);
     return c->setSwapInterval(interval);
diff --git a/libs/gui/tests/BufferQueue_test.cpp b/libs/gui/tests/BufferQueue_test.cpp
index a32a90c..a45a5be 100644
--- a/libs/gui/tests/BufferQueue_test.cpp
+++ b/libs/gui/tests/BufferQueue_test.cpp
@@ -535,4 +535,66 @@
     }
 }
 
+TEST_F(BufferQueueTest, TestTimeouts) {
+    createBufferQueue();
+    sp<DummyConsumer> dc(new DummyConsumer);
+    ASSERT_EQ(OK, mConsumer->consumerConnect(dc, true));
+    IGraphicBufferProducer::QueueBufferOutput output;
+    ASSERT_EQ(OK, mProducer->connect(new DummyProducerListener,
+            NATIVE_WINDOW_API_CPU, true, &output));
+
+    // Fill up the queue. Since the controlledByApp flags are set to true, this
+    // queue should be in non-blocking mode, and we should be recycling the same
+    // two buffers
+    for (int i = 0; i < 5; ++i) {
+        int slot = BufferQueue::INVALID_BUFFER_SLOT;
+        sp<Fence> fence = Fence::NO_FENCE;
+        auto result = mProducer->dequeueBuffer(&slot, &fence, 0, 0, 0, 0);
+        if (i < 2) {
+            ASSERT_EQ(IGraphicBufferProducer::BUFFER_NEEDS_REALLOCATION,
+                    result);
+        } else {
+            ASSERT_EQ(OK, result);
+        }
+        sp<GraphicBuffer> buffer;
+        ASSERT_EQ(OK, mProducer->requestBuffer(slot, &buffer));
+        IGraphicBufferProducer::QueueBufferInput input(0ull, true,
+                HAL_DATASPACE_UNKNOWN, Rect::INVALID_RECT,
+                NATIVE_WINDOW_SCALING_MODE_FREEZE, 0, Fence::NO_FENCE);
+        IGraphicBufferProducer::QueueBufferOutput output{};
+        ASSERT_EQ(OK, mProducer->queueBuffer(slot, input, &output));
+    }
+
+    const auto TIMEOUT = ms2ns(250);
+    mProducer->setDequeueTimeout(TIMEOUT);
+
+    // Setting a timeout will change the BufferQueue into blocking mode (with
+    // one droppable buffer in the queue and one free from the previous
+    // dequeue/queues), so dequeue and queue two more buffers: one to replace
+    // the current droppable buffer, and a second to max out the buffer count
+    sp<GraphicBuffer> buffer; // Save a buffer to attach later
+    for (int i = 0; i < 2; ++i) {
+        int slot = BufferQueue::INVALID_BUFFER_SLOT;
+        sp<Fence> fence = Fence::NO_FENCE;
+        ASSERT_EQ(OK, mProducer->dequeueBuffer(&slot, &fence, 0, 0, 0, 0));
+        ASSERT_EQ(OK, mProducer->requestBuffer(slot, &buffer));
+        IGraphicBufferProducer::QueueBufferInput input(0ull, true,
+                HAL_DATASPACE_UNKNOWN, Rect::INVALID_RECT,
+                NATIVE_WINDOW_SCALING_MODE_FREEZE, 0, Fence::NO_FENCE);
+        ASSERT_EQ(OK, mProducer->queueBuffer(slot, input, &output));
+    }
+
+    int slot = BufferQueue::INVALID_BUFFER_SLOT;
+    sp<Fence> fence = Fence::NO_FENCE;
+    auto startTime = systemTime();
+    ASSERT_EQ(TIMED_OUT, mProducer->dequeueBuffer(&slot, &fence, 0, 0, 0, 0));
+    ASSERT_GE(systemTime() - startTime, TIMEOUT);
+
+    // We're technically attaching the same buffer multiple times (since we
+    // queued it previously), but that doesn't matter for this test
+    startTime = systemTime();
+    ASSERT_EQ(TIMED_OUT, mProducer->attachBuffer(&slot, buffer));
+    ASSERT_GE(systemTime() - startTime, TIMEOUT);
+}
+
 } // namespace android