Notify applications when input devices change.

This change allows the InputManager to keep track of what input
devices are registered with the system and when they change.
It needs to do this so that it can properly clear its cache of
input device properties (especially the key map!) when changes
occur.

Added new API so that applications can register listeners for
input device changes.

Fixed a minor bug in EventHub where it didn't handle EPOLLHUP
properly so it would spam the log about unsupposed epoll events
until inotify noticed that the device was gone and removed it.

Change-Id: I937d8c601f7185d4299038bce6a2934fe4fdd2b3

Author: Jeff Brown

Android.mk

@@ -111,6 +111,7 @@ LOCAL_SRC_FILES += \
 	core/java/android/database/IContentObserver.aidl \
 	core/java/android/hardware/ISerialManager.aidl \
 	core/java/android/hardware/input/IInputManager.aidl \
+	core/java/android/hardware/input/IInputDevicesChangedListener.aidl \
 	core/java/android/hardware/usb/IUsbManager.aidl \
 	core/java/android/net/IConnectivityManager.aidl \
 	core/java/android/net/INetworkManagementEventObserver.aidl \

api/current.txt

@@ -9820,10 +9820,20 @@ package android.hardware {
 package android.hardware.input {
 
   public final class InputManager {
+    method public android.view.InputDevice getInputDevice(int);
+    method public int[] getInputDeviceIds();
+    method public void registerInputDeviceListener(android.hardware.input.InputManager.InputDeviceListener, android.os.Handler);
+    method public void unregisterInputDeviceListener(android.hardware.input.InputManager.InputDeviceListener);
     field public static final java.lang.String ACTION_QUERY_KEYBOARD_LAYOUTS = "android.hardware.input.action.QUERY_KEYBOARD_LAYOUTS";
     field public static final java.lang.String META_DATA_KEYBOARD_LAYOUTS = "android.hardware.input.metadata.KEYBOARD_LAYOUTS";
   }
 
+  public static abstract interface InputManager.InputDeviceListener {
+    method public abstract void onInputDeviceAdded(int);
+    method public abstract void onInputDeviceChanged(int);
+    method public abstract void onInputDeviceRemoved(int);
+  }
+
 }
 
 package android.hardware.usb {

core/java/android/hardware/input/IInputDevicesChangedListener.aidl

@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2012 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.
+ */
+
+package android.hardware.input;
+
+/** @hide */
+interface IInputDevicesChangedListener {
+    /* Called when input devices changed, such as a device being added,
+     * removed or changing configuration.
+     *
+     * The parameter is an array of pairs (deviceId, generation) indicating the current
+     * device id and generation of all input devices.  The client can determine what
+     * has happened by comparing the result to its prior observations.
+     */
+    oneway void onInputDevicesChanged(in int[] deviceIdAndGeneration);
+}

core/java/android/hardware/input/IInputManager.aidl

@@ -17,6 +17,7 @@
 package android.hardware.input;
 
 import android.hardware.input.KeyboardLayout;
+import android.hardware.input.IInputDevicesChangedListener;
 import android.view.InputDevice;
 import android.view.InputEvent;
 
@@ -42,4 +43,7 @@ interface IInputManager {
     String getKeyboardLayoutForInputDevice(String inputDeviceDescriptor);
     void setKeyboardLayoutForInputDevice(String inputDeviceDescriptor,
             String keyboardLayoutDescriptor);
+
+    // Registers an input devices changed listener.
+    void registerInputDevicesChangedListener(IInputDevicesChangedListener listener);
 }