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diff --git a/libshims/gui/DisplayEventReceiver.h b/libshims/gui/DisplayEventReceiver.h
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+/*
+ * 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.
+ */
+
+#ifndef ANDROID_GUI_DISPLAY_EVENT_H
+#define ANDROID_GUI_DISPLAY_EVENT_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <utils/Errors.h>
+#include <utils/RefBase.h>
+#include <utils/Timers.h>
+
+#include <binder/IInterface.h>
+#include <gui/ISurfaceComposer.h>
+
+// ----------------------------------------------------------------------------
+
+namespace android {
+
+// ----------------------------------------------------------------------------
+
+class IDisplayEventConnection;
+
+namespace gui {
+class BitTube;
+} // namespace gui
+
+static inline constexpr uint32_t fourcc(char c1, char c2, char c3, char c4) {
+    return static_cast<uint32_t>(c1) << 24 |
+        static_cast<uint32_t>(c2) << 16 |
+        static_cast<uint32_t>(c3) << 8 |
+        static_cast<uint32_t>(c4);
+}
+
+// ----------------------------------------------------------------------------
+class DisplayEventReceiver {
+public:
+    enum {
+        DISPLAY_EVENT_VSYNC = fourcc('v', 's', 'y', 'n'),
+        DISPLAY_EVENT_HOTPLUG = fourcc('p', 'l', 'u', 'g'),
+    };
+
+    struct Event {
+
+        struct Header {
+            uint32_t type;
+            uint32_t id;
+            nsecs_t timestamp __attribute__((aligned(8)));
+        };
+
+        struct VSync {
+            uint32_t count;
+        };
+
+        struct Hotplug {
+            bool connected;
+        };
+
+        Header header;
+        union {
+            VSync vsync;
+            Hotplug hotplug;
+        };
+    };
+
+public:
+    DisplayEventReceiver();
+    /*
+     * DisplayEventReceiver creates and registers an event connection with
+     * SurfaceFlinger. VSync events are disabled by default. Call setVSyncRate
+     * or requestNextVsync to receive them.
+     * Other events start being delivered immediately.
+     */
+    DisplayEventReceiver(
+            ISurfaceComposer::VsyncSource vsyncSource = ISurfaceComposer::eVsyncSourceApp);
+
+    /*
+     * ~DisplayEventReceiver severs the connection with SurfaceFlinger, new events
+     * stop being delivered immediately. Note that the queue could have
+     * some events pending. These will be delivered.
+     */
+    ~DisplayEventReceiver();
+
+    /*
+     * initCheck returns the state of DisplayEventReceiver after construction.
+     */
+    status_t initCheck() const;
+
+    /*
+     * getFd returns the file descriptor to use to receive events.
+     * OWNERSHIP IS RETAINED by DisplayEventReceiver. DO NOT CLOSE this
+     * file-descriptor.
+     */
+    int getFd() const;
+
+    /*
+     * getEvents reads events from the queue and returns how many events were
+     * read. Returns 0 if there are no more events or a negative error code.
+     * If NOT_ENOUGH_DATA is returned, the object has become invalid forever, it
+     * should be destroyed and getEvents() shouldn't be called again.
+     */
+    ssize_t getEvents(Event* events, size_t count);
+    static ssize_t getEvents(gui::BitTube* dataChannel, Event* events, size_t count);
+
+    /*
+     * sendEvents write events to the queue and returns how many events were
+     * written.
+     */
+    static ssize_t sendEvents(gui::BitTube* dataChannel, Event const* events, size_t count);
+
+    /*
+     * setVsyncRate() sets the Event::VSync delivery rate. A value of
+     * 1 returns every Event::VSync. A value of 2 returns every other event,
+     * etc... a value of 0 returns no event unless  requestNextVsync() has
+     * been called.
+     */
+    status_t setVsyncRate(uint32_t count);
+
+    /*
+     * requestNextVsync() schedules the next Event::VSync. It has no effect
+     * if the vsync rate is > 0.
+     */
+    status_t requestNextVsync();
+
+private:
+    sp<IDisplayEventConnection> mEventConnection;
+    std::unique_ptr<gui::BitTube> mDataChannel;
+};
+
+// ----------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_GUI_DISPLAY_EVENT_H