Add support for sending VSYNC events to the framework
use gui/DisplayEvent to receive the events. Events are
dispatched through a unix pipe, so the API is compatible
with utils/Looper. see gui/DisplayEvent.h for more info.
Bug: 1475048
Change-Id: Ia720f64d1b950328b47b22c6a86042e481d35f09
diff --git a/libs/gui/DisplayEventReceiver.cpp b/libs/gui/DisplayEventReceiver.cpp
new file mode 100644
index 0000000..3b29a11
--- /dev/null
+++ b/libs/gui/DisplayEventReceiver.cpp
@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2011 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.
+ */
+
+#include <string.h>
+
+#include <utils/Errors.h>
+
+#include <gui/BitTube.h>
+#include <gui/DisplayEventReceiver.h>
+#include <gui/IDisplayEventConnection.h>
+
+#include <private/gui/ComposerService.h>
+
+#include <surfaceflinger/ISurfaceComposer.h>
+
+// ---------------------------------------------------------------------------
+
+namespace android {
+
+// ---------------------------------------------------------------------------
+
+DisplayEventReceiver::DisplayEventReceiver() {
+ sp<ISurfaceComposer> sf(ComposerService::getComposerService());
+ if (sf != NULL) {
+ mEventConnection = sf->createDisplayEventConnection();
+ if (mEventConnection != NULL) {
+ mDataChannel = mEventConnection->getDataChannel();
+ }
+ }
+}
+
+DisplayEventReceiver::~DisplayEventReceiver() {
+}
+
+status_t DisplayEventReceiver::initCheck() const {
+ if (mDataChannel != NULL)
+ return NO_ERROR;
+ return NO_INIT;
+}
+
+int DisplayEventReceiver::getFd() const {
+ if (mDataChannel == NULL)
+ return NO_INIT;
+
+ return mDataChannel->getFd();
+}
+
+ssize_t DisplayEventReceiver::getEvents(DisplayEventReceiver::Event* events,
+ size_t count) {
+ ssize_t size = mDataChannel->read(events, sizeof(events[0])*count);
+ LOGE_IF(size<0,
+ "DisplayEventReceiver::getEvents error (%s)",
+ strerror(-size));
+ if (size >= 0) {
+ // Note: if (size % sizeof(events[0])) != 0, we've got a
+ // partial read. This can happen if the queue filed up (ie: if we
+ // didn't pull from it fast enough).
+ // We discard the partial event and rely on the sender to
+ // re-send the event if appropriate (some events, like VSYNC
+ // can be lost forever).
+
+ // returns number of events read
+ size /= sizeof(events[0]);
+ }
+ return size;
+}
+
+// ---------------------------------------------------------------------------
+
+}; // namespace android