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/Android.mk b/libs/gui/Android.mk
index b7e3ee3..b8be67d 100644
--- a/libs/gui/Android.mk
+++ b/libs/gui/Android.mk
@@ -3,6 +3,8 @@
 
 LOCAL_SRC_FILES:= \
 	BitTube.cpp \
+	DisplayEventReceiver.cpp \
+	IDisplayEventConnection.cpp \
 	ISensorEventConnection.cpp \
 	ISensorServer.cpp \
 	ISurfaceTexture.cpp \
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
diff --git a/libs/gui/IDisplayEventConnection.cpp b/libs/gui/IDisplayEventConnection.cpp
new file mode 100644
index 0000000..44127fb
--- /dev/null
+++ b/libs/gui/IDisplayEventConnection.cpp
@@ -0,0 +1,73 @@
+/*
+ * 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 <stdint.h>
+#include <sys/types.h>
+
+#include <utils/Errors.h>
+#include <utils/RefBase.h>
+#include <utils/Timers.h>
+
+#include <binder/Parcel.h>
+#include <binder/IInterface.h>
+
+#include <gui/IDisplayEventConnection.h>
+#include <gui/BitTube.h>
+
+namespace android {
+// ----------------------------------------------------------------------------
+
+enum {
+    GET_DATA_CHANNEL = IBinder::FIRST_CALL_TRANSACTION,
+};
+
+class BpDisplayEventConnection : public BpInterface<IDisplayEventConnection>
+{
+public:
+    BpDisplayEventConnection(const sp<IBinder>& impl)
+        : BpInterface<IDisplayEventConnection>(impl)
+    {
+    }
+
+    virtual sp<BitTube> getDataChannel() const
+    {
+        Parcel data, reply;
+        data.writeInterfaceToken(IDisplayEventConnection::getInterfaceDescriptor());
+        remote()->transact(GET_DATA_CHANNEL, data, &reply);
+        return new BitTube(reply);
+    }
+};
+
+IMPLEMENT_META_INTERFACE(DisplayEventConnection, "android.gui.DisplayEventConnection");
+
+// ----------------------------------------------------------------------------
+
+status_t BnDisplayEventConnection::onTransact(
+    uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
+{
+    switch(code) {
+        case GET_DATA_CHANNEL: {
+            CHECK_INTERFACE(IDisplayEventConnection, data, reply);
+            sp<BitTube> channel(getDataChannel());
+            channel->writeToParcel(reply);
+            return NO_ERROR;
+        } break;
+    }
+    return BBinder::onTransact(code, data, reply, flags);
+}
+
+// ----------------------------------------------------------------------------
+}; // namespace android
diff --git a/libs/gui/ISurfaceComposer.cpp b/libs/gui/ISurfaceComposer.cpp
index 86bc62a..db32827 100644
--- a/libs/gui/ISurfaceComposer.cpp
+++ b/libs/gui/ISurfaceComposer.cpp
@@ -29,6 +29,9 @@
 
 #include <surfaceflinger/ISurfaceComposer.h>
 
+#include <gui/BitTube.h>
+#include <gui/IDisplayEventConnection.h>
+
 #include <ui/DisplayInfo.h>
 
 #include <gui/ISurfaceTexture.h>
@@ -44,6 +47,8 @@
 
 namespace android {
 
+class IDisplayEventConnection;
+
 class BpSurfaceComposer : public BpInterface<ISurfaceComposer>
 {
 public:
@@ -174,6 +179,27 @@
         }
         return result != 0;
     }
+
+    virtual sp<IDisplayEventConnection> createDisplayEventConnection()
+    {
+        Parcel data, reply;
+        sp<IDisplayEventConnection> result;
+        int err = data.writeInterfaceToken(
+                ISurfaceComposer::getInterfaceDescriptor());
+        if (err != NO_ERROR) {
+            return result;
+        }
+        err = remote()->transact(
+                BnSurfaceComposer::CREATE_DISPLAY_EVENT_CONNECTION,
+                data, &reply);
+        if (err != NO_ERROR) {
+            LOGE("ISurfaceComposer::createDisplayEventConnection: error performing "
+                    "transaction: %s (%d)", strerror(-err), -err);
+            return result;
+        }
+        result = interface_cast<IDisplayEventConnection>(reply.readStrongBinder());
+        return result;
+    }
 };
 
 IMPLEMENT_META_INTERFACE(SurfaceComposer, "android.ui.ISurfaceComposer");
@@ -254,6 +280,12 @@
             int32_t result = authenticateSurfaceTexture(surfaceTexture) ? 1 : 0;
             reply->writeInt32(result);
         } break;
+        case CREATE_DISPLAY_EVENT_CONNECTION: {
+            CHECK_INTERFACE(ISurfaceComposer, data, reply);
+            sp<IDisplayEventConnection> connection(createDisplayEventConnection());
+            reply->writeStrongBinder(connection->asBinder());
+            return NO_ERROR;
+        } break;
         default:
             return BBinder::onTransact(code, data, reply, flags);
     }