recovery: Move SwipeDetector into common location

The SwipeDetector class is used almost unchanged in all locations.

This patch moves it into the recovery module, from which devices can
reference it if required.

The class is now renamed to WearSwipeDetector.

Bug: 27407422
Change-Id: Ifd3c7069a287548b89b14ab5d6d2b90a298e0145
diff --git a/wear_touch.cpp b/wear_touch.cpp
new file mode 100644
index 0000000..f22d40b
--- /dev/null
+++ b/wear_touch.cpp
@@ -0,0 +1,177 @@
+/*
+ * Copyright (C) 2016 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 "common.h"
+#include "wear_touch.h"
+
+#include <dirent.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+
+#include <linux/input.h>
+
+#define DEVICE_PATH "/dev/input"
+
+WearSwipeDetector::WearSwipeDetector(int low, int high, OnSwipeCallback callback, void* cookie):
+    mLowThreshold(low),
+    mHighThreshold(high),
+    mCallback(callback),
+    mCookie(cookie),
+    mCurrentSlot(-1) {
+    pthread_create(&mThread, NULL, touch_thread, this);
+}
+
+WearSwipeDetector::~WearSwipeDetector() {
+}
+
+void WearSwipeDetector::detect(int dx, int dy) {
+    enum SwipeDirection direction;
+
+    if (abs(dy) < mLowThreshold && abs(dx) > mHighThreshold) {
+        direction = dx < 0 ? LEFT : RIGHT;
+    } else if (abs(dx) < mLowThreshold && abs(dy) > mHighThreshold) {
+        direction = dy < 0 ? UP : DOWN;
+    } else {
+        LOGD("Ignore %d %d\n", dx, dy);
+        return;
+    }
+
+    LOGD("Swipe direction=%d\n", direction);
+    mCallback(mCookie, direction);
+}
+
+void WearSwipeDetector::process(struct input_event *event) {
+    if (mCurrentSlot < 0) {
+        mCallback(mCookie, UP);
+        mCurrentSlot = 0;
+    }
+
+    if (event->type == EV_ABS) {
+        if (event->code == ABS_MT_SLOT)
+            mCurrentSlot = event->value;
+
+        // Ignore other fingers
+        if (mCurrentSlot > 0) {
+            return;
+        }
+
+        switch (event->code) {
+        case ABS_MT_POSITION_X:
+            mX = event->value;
+            mFingerDown = true;
+            break;
+
+        case ABS_MT_POSITION_Y:
+            mY = event->value;
+            mFingerDown = true;
+            break;
+
+        case ABS_MT_TRACKING_ID:
+            if (event->value < 0)
+                mFingerDown = false;
+            break;
+        }
+    } else if (event->type == EV_SYN) {
+        if (event->code == SYN_REPORT) {
+            if (mFingerDown && !mSwiping) {
+                mStartX = mX;
+                mStartY = mY;
+                mSwiping = true;
+            } else if (!mFingerDown && mSwiping) {
+                mSwiping = false;
+                detect(mX - mStartX, mY - mStartY);
+            }
+        }
+    }
+}
+
+void WearSwipeDetector::run() {
+    int fd = findDevice(DEVICE_PATH);
+    if (fd < 0) {
+        LOGE("no input devices found\n");
+        return;
+    }
+
+    struct input_event event;
+    while (read(fd, &event, sizeof(event)) == sizeof(event)) {
+        process(&event);
+    }
+
+    close(fd);
+}
+
+void* WearSwipeDetector::touch_thread(void* cookie) {
+    ((WearSwipeDetector*)cookie)->run();
+    return NULL;
+}
+
+#define test_bit(bit, array)    (array[bit/8] & (1<<(bit%8)))
+
+int WearSwipeDetector::openDevice(const char *device) {
+    int fd = open(device, O_RDONLY);
+    if (fd < 0) {
+        LOGE("could not open %s, %s\n", device, strerror(errno));
+        return false;
+    }
+
+    char name[80];
+    name[sizeof(name) - 1] = '\0';
+    if (ioctl(fd, EVIOCGNAME(sizeof(name) - 1), &name) < 1) {
+        LOGE("could not get device name for %s, %s\n", device, strerror(errno));
+        name[0] = '\0';
+    }
+
+    uint8_t bits[512];
+    memset(bits, 0, sizeof(bits));
+    int ret = ioctl(fd, EVIOCGBIT(EV_ABS, sizeof(bits)), bits);
+    if (ret > 0) {
+        if (test_bit(ABS_MT_POSITION_X, bits) && test_bit(ABS_MT_POSITION_Y, bits)) {
+            LOGD("Found %s %s\n", device, name);
+            return fd;
+        }
+    }
+
+    close(fd);
+    return -1;
+}
+
+int WearSwipeDetector::findDevice(const char* path) {
+    DIR* dir = opendir(path);
+    if (dir == NULL) {
+        LOGE("Could not open directory %s", path);
+        return false;
+    }
+
+    struct dirent* entry;
+    int ret = -1;
+    while (ret < 0 && (entry = readdir(dir)) != NULL) {
+        if (entry->d_name[0] == '.') continue;
+
+        char device[PATH_MAX];
+        device[PATH_MAX-1] = '\0';
+        snprintf(device, PATH_MAX-1, "%s/%s", path, entry->d_name);
+
+        ret = openDevice(device);
+    }
+
+    closedir(dir);
+    return ret;
+}
+