[Chromoting] Add InputInjector and InputInjectorWrapper for easy unittesting

remoting/android/java/src/org/chromium/chromoting/InputInjectorWrapper.java

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chromoting;
+
+import android.graphics.Point;
+import android.view.KeyEvent;
+import android.view.MotionEvent;
+
+import org.chromium.chromoting.jni.TouchEventData;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+import java.util.TreeSet;
+
+/**
+ * A set of functions to send users' activities, which are represented by Android classes, to
+ * remove host machine. This class uses a {@link InputInjector} to do the real injections.
+ */
+public final class InputInjectorWrapper {

[Sergey Ulanov, 2016/06/22 06:39:01]

I don't think this is the best name for this class. I would normally expect a
wrapper to implement the same interface as the one it wraps, which is not the
case here. Maybe call it InputEventSender or something like that?

[Hzj_jie, 2016/06/22 23:18:54]

Done.

+    private static final int[] CTRL_ALT_DEL = {
+            KeyEvent.KEYCODE_CTRL_LEFT, KeyEvent.KEYCODE_ALT_LEFT, KeyEvent.KEYCODE_FORWARD_DEL,
+    };
+
+    private final InputInjector mInjector;
+
+    /** Set of pressed keys for which we've sent TextEvent. */
+    private final Set<Integer> mPressedTextKeys;
+
+    public InputInjectorWrapper(InputInjector injector) {
+        Preconditions.notNull(injector);
+        mInjector = injector;
+        mPressedTextKeys = new TreeSet<>();
+    }
+
+    public void sendMouseEvent(Point pos, int button, boolean down) {
+        Preconditions.isTrue(button == TouchInputHandler.BUTTON_UNDEFINED
+                || button == TouchInputHandler.BUTTON_LEFT
+                || button == TouchInputHandler.BUTTON_MIDDLE
+                || button == TouchInputHandler.BUTTON_RIGHT);
+        mInjector.sendMouseEvent(pos.x, pos.y, button, down);
+    }
+
+    public void sendMouseDown(Point pos, int button) {
+        sendMouseEvent(pos, button, true);
+    }
+
+    public void sendMouseUp(Point pos, int button) {
+        sendMouseEvent(pos, button, false);
+    }
+
+    public void sendMouseClick(Point pos, int button) {
+        sendMouseDown(pos, button);
+        sendMouseUp(pos, button);
+    }
+
+    public void sendCursorMove(Point pos) {
+        sendMouseUp(pos, TouchInputHandler.BUTTON_UNDEFINED);
+    }
+
+    // TODO (zijiehe): This function will be eventually removed after {@link InputStrategyInterface}

[Lambros, 2016/06/22 01:43:14]

No space between TODO and (.

[Hzj_jie, 2016/06/22 23:18:54]

Done.

+    // has been deprecated.
+    public void sendCursorMove(int x, int y) {
+        sendCursorMove(new Point(x, y));
+    }
+
+    public void sendMouseWheelEvent(float distanceX, float distanceY) {
+        mInjector.sendMouseWheelEvent((int) distanceX, (int) distanceY);
+    }
+
+    public void sendReverseMouseWheelEvent(float distanceX, float distanceY) {
+        sendMouseWheelEvent(-distanceX, -distanceY);
+    }
+
+    /**
+     * Extracts the touch point data from a MotionEvent, converts each point into a marshallable
+     * object and passes the set of points to the JNI layer to be transmitted to the remote host.
+     *
+     * @param event The event to send to the remote host for injection.  NOTE: This object must be
+     *              updated to represent the remote machine's coordinate system before calling this
+     *              function.
+     */
+    public void sendTouchEvent(MotionEvent event) {
+        int action = event.getActionMasked();
+        TouchEventData.EventType touchEventType = TouchEventData.EventType.fromMaskedAction(action);
+        List<TouchEventData> touchEventList = new ArrayList<TouchEventData>();
+
+        if (action == MotionEvent.ACTION_MOVE) {
+            // In order to process all of the events associated with an ACTION_MOVE event, we need
+            // to walk the list of historical events in order and add each event to our list, then
+            // retrieve the current move event data.
+            int pointerCount = event.getPointerCount();
+            int historySize = event.getHistorySize();
+            for (int h = 0; h < historySize; ++h) {
+                for (int p = 0; p < pointerCount; ++p) {
+                    touchEventList.add(new TouchEventData(event.getPointerId(p),
+                            event.getHistoricalX(p, h), event.getHistoricalY(p, h),
+                            event.getHistoricalSize(p, h), event.getHistoricalSize(p, h),
+                            event.getHistoricalOrientation(p, h),
+                            event.getHistoricalPressure(p, h)));
+                }
+            }
+
+            for (int p = 0; p < pointerCount; p++) {
+                touchEventList.add(new TouchEventData(event.getPointerId(p), event.getX(p),
+                        event.getY(p), event.getSize(p), event.getSize(p), event.getOrientation(p),
+                        event.getPressure(p)));
+            }
+        } else {
+            // For all other events, we only want to grab the current/active pointer.  The event
+            // contains a list of every active pointer but passing all of of these to the host can
+            // cause confusion on the remote OS side and result in broken touch gestures.
+            int activePointerIndex = event.getActionIndex();
+            touchEventList.add(new TouchEventData(event.getPointerId(activePointerIndex),
+                    event.getX(activePointerIndex), event.getY(activePointerIndex),
+                    event.getSize(activePointerIndex), event.getSize(activePointerIndex),
+                    event.getOrientation(activePointerIndex),
+                    event.getPressure(activePointerIndex)));
+        }
+
+        if (!touchEventList.isEmpty()) {
+            mInjector.sendTouchEvent(touchEventType, touchEventList.toArray(new TouchEventData[0]));
+        }
+    }
+
+    /**
+     * Converts the {@link KeyEvent} into low-level events and sends them to the host as either
+     * key-events or text-events. This contains some logic for handling some special keys, and
+     * avoids sending a key-up event for a key that was previously injected as a text-event.
+     */
+    public boolean sendKeyEvent(KeyEvent event) {
+        int keyCode = event.getKeyCode();
+        boolean pressed = event.getAction() == KeyEvent.ACTION_DOWN;
+
+        // Events received from software keyboards generate TextEvent in two
+        // cases:
+        //   1. This is an ACTION_MULTIPLE event.
+        //   2. Ctrl, Alt and Meta are not pressed.
+        // This ensures that on-screen keyboard always injects input that
+        // correspond to what user sees on the screen, while physical keyboard
+        // acts as if it is connected to the remote host.
+        if (event.getAction() == KeyEvent.ACTION_MULTIPLE) {
+            mInjector.sendTextEvent(event.getCharacters());
+            return true;
+        }
+
+        // For Enter getUnicodeChar() returns 10 (line feed), but we still
+        // want to send it as KeyEvent.
+        int unicode = keyCode != KeyEvent.KEYCODE_ENTER ? event.getUnicodeChar() : 0;
+
+        boolean no_modifiers =
+                !event.isAltPressed() && !event.isCtrlPressed() && !event.isMetaPressed();
+
+        if (pressed && unicode != 0 && no_modifiers) {
+            mPressedTextKeys.add(keyCode);
+            int[] codePoints = {unicode};
+            mInjector.sendTextEvent(new String(codePoints, 0, 1));
+            return true;
+        }
+
+        if (!pressed && mPressedTextKeys.contains(keyCode)) {
+            mPressedTextKeys.remove(keyCode);
+            return true;
+        }
+
+        switch (keyCode) {
+            // KEYCODE_AT, KEYCODE_POUND, KEYCODE_STAR and KEYCODE_PLUS are
+            // deprecated, but they still need to be here for older devices and
+            // third-party keyboards that may still generate these events. See
+            // https://source.android.com/devices/input/keyboard-devices.html#legacy-unsupported-keys
+            case KeyEvent.KEYCODE_AT:
+                mInjector.sendKeyEvent(0, KeyEvent.KEYCODE_SHIFT_LEFT, pressed);
+                mInjector.sendKeyEvent(0, KeyEvent.KEYCODE_2, pressed);
+                return true;
+
+            case KeyEvent.KEYCODE_POUND:
+                mInjector.sendKeyEvent(0, KeyEvent.KEYCODE_SHIFT_LEFT, pressed);
+                mInjector.sendKeyEvent(0, KeyEvent.KEYCODE_3, pressed);
+                return true;
+
+            case KeyEvent.KEYCODE_STAR:
+                mInjector.sendKeyEvent(0, KeyEvent.KEYCODE_SHIFT_LEFT, pressed);
+                mInjector.sendKeyEvent(0, KeyEvent.KEYCODE_8, pressed);
+                return true;
+
+            case KeyEvent.KEYCODE_PLUS:
+                mInjector.sendKeyEvent(0, KeyEvent.KEYCODE_SHIFT_LEFT, pressed);
+                mInjector.sendKeyEvent(0, KeyEvent.KEYCODE_EQUALS, pressed);
+                return true;
+
+            default:
+                // We try to send all other key codes to the host directly.
+                return mInjector.sendKeyEvent(0, keyCode, pressed);
+        }
+    }
+
+    public void sendKeyDown(int keyCode) {
+        mInjector.sendKeyEvent(0, keyCode, true);
+    }
+
+    public void sendKeyUp(int keyCode) {
+        mInjector.sendKeyEvent(0, keyCode, false);
+    }
+
+    /**
+     * Sends key combinations such as Ctrl-Alt-Del. This injects a key-down event for every key in
+     * the list, and then injects the corresponding key-up events.
+     */
+    public void sendKeysPress(int[] keyCodes) {
+        if (keyCodes != null && keyCodes.length > 0) {

[Lambros, 2016/06/22 01:43:14]

I don't think you need a null check, and the length check is not needed either.

[Hzj_jie, 2016/06/22 23:18:54]

I believe Java allows an array to be null. And for each through a null array
will result a NullPointerException. So removing the null check equals to an
assert keyCodes != null. I agree we should not have this case in our code path,
but this check can make it safer. A no-op should be better than a crash error,
right?

[Lambros, 2016/06/23 01:40:09]

Arguably, it can be better to crash than to silently ignore mistakes.
If the application crashes, we can become aware of the programmer
error and we can fix the problem.

I don't feel strongly - it's fine to keep or remove the check.
If you keep the null-check, maybe update JavaDoc to say that the
parameter can be null and nothing will be injected?

[Hzj_jie, 2016/06/23 18:03:23]

Done.

+            for (int keyCode : keyCodes) {
+                sendKeyDown(keyCode);
+            }
+            for (int keyCode : keyCodes) {
+                sendKeyUp(keyCode);
+            }
+        }
+    }
+
+    public void sendCtrlAltDel() {
+        sendKeysPress(CTRL_ALT_DEL);
+    }
+}