Move TouchVideoDevice.h
The header file TouchVideoDevice.h does not need to be in the include/
folder, now that EventHub.h has been moved out of there.
Also, make a doc clarification on TouchVideoDevice. The frames are in
the order that they were received from v4l2 device.
Test: presubmit only
Bug: 117935272
Change-Id: Idacbf54bca4398079401b3a4a5a7cdd020a7263b
diff --git a/services/inputflinger/TouchVideoDevice.h b/services/inputflinger/TouchVideoDevice.h
new file mode 100644
index 0000000..3d5c8c6
--- /dev/null
+++ b/services/inputflinger/TouchVideoDevice.h
@@ -0,0 +1,125 @@
+/*
+ * Copyright (C) 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.
+ */
+
+#ifndef _INPUTFLINGER_TOUCH_VIDEO_DEVICE_H
+#define _INPUTFLINGER_TOUCH_VIDEO_DEVICE_H
+
+#include <array>
+#include <android-base/unique_fd.h>
+#include <input/TouchVideoFrame.h>
+#include <optional>
+#include <stdint.h>
+#include <string>
+#include <vector>
+
+namespace android {
+
+/**
+ * Represents a video device that uses v4l2 api to report touch heatmap data.
+ */
+class TouchVideoDevice {
+public:
+ /**
+ * Create a new TouchVideoDevice for the path provided.
+ * Return nullptr upon failure.
+ */
+ static std::unique_ptr<TouchVideoDevice> create(std::string devicePath);
+ ~TouchVideoDevice();
+
+ bool hasValidFd() const { return mFd.get() != INVALID_FD; }
+ /**
+ * Obtain the file descriptor associated with this video device.
+ * Could be used for adding to epoll.
+ */
+ int getFd() const { return mFd.get(); }
+ /**
+ * Get the name of this video device.
+ */
+ const std::string& getName() const { return mName; }
+ /**
+ * Get the file path of this video device.
+ */
+ const std::string& getPath() const { return mPath; }
+ /**
+ * Get the width of the heatmap frame
+ */
+ uint32_t getWidth() const { return mWidth; }
+ /**
+ * Get the height of the heatmap frame
+ */
+ uint32_t getHeight() const { return mHeight; }
+ /**
+ * Direct read of the frame. Stores the frame into internal buffer.
+ * Return the number of frames that were successfully read.
+ *
+ * This function should not be called unless buffer is ready!
+ * This must be checked with select, poll, epoll, or similar api first.
+ * If epoll indicates that there is data ready to read, but this function
+ * returns zero, then it is likely an error occurred.
+ */
+ size_t readAndQueueFrames();
+ /**
+ * Return all of the queued frames, and erase them from the local buffer.
+ * The returned frames are in the order that they were received from the
+ * v4l2 device, with the oldest frame at the index 0.
+ */
+ std::vector<TouchVideoFrame> consumeFrames();
+ /**
+ * Get string representation of this video device.
+ */
+ std::string dump() const;
+
+private:
+ android::base::unique_fd mFd;
+ std::string mName;
+ std::string mPath;
+
+ uint32_t mWidth;
+ uint32_t mHeight;
+
+ static constexpr int INVALID_FD = -1;
+ /**
+ * How many buffers to request for heatmap.
+ * The kernel driver will be allocating these buffers for us,
+ * and will provide memory locations to read these from.
+ */
+ static constexpr size_t NUM_BUFFERS = 3;
+ std::array<const int16_t*, NUM_BUFFERS> mReadLocations;
+ /**
+ * How many buffers to keep for the internal queue. When the internal buffer
+ * exceeds this capacity, oldest frames will be dropped.
+ */
+ static constexpr size_t MAX_QUEUE_SIZE = 10;
+ std::vector<TouchVideoFrame> mFrames;
+
+ /**
+ * The constructor is private because opening a v4l2 device requires many checks.
+ * To get a new TouchVideoDevice, use 'create' instead.
+ */
+ explicit TouchVideoDevice(int fd, std::string&& name, std::string&& devicePath,
+ uint32_t width, uint32_t height,
+ const std::array<const int16_t*, NUM_BUFFERS>& readLocations);
+ /**
+ * Read all currently available frames.
+ */
+ std::vector<TouchVideoFrame> readFrames();
+ /**
+ * Read a single frame. May return nullopt if no data is currently available for reading.
+ */
+ std::optional<TouchVideoFrame> readFrame();
+};
+} // namespace android
+#endif //_INPUTFLINGER_TOUCH_VIDEO_DEVICE_H