Dispatch keys to a device specific key handler

Injects a device key handler into the input path to handle additional
keys (as found on some docks with a hardware keyboard).

Configurable via overlay settings config_deviceKeyHandlerLib and
config_deviceKeyHandlerClass.

Change-Id: I6678c89c7530fdb1d4d516ba4f1d2c9e30ce79a4

Conflicts:
	core/res/res/values/symbols.xml

Author: aleho

core/java/com/android/internal/os/DeviceKeyHandler.java

@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2012 The CyanogenMod 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 com.android.internal.os;
+
+import android.view.KeyEvent;
+
+public interface DeviceKeyHandler {
+    public static final int KEYEVENT_CAUGHT = -1;
+    public static final int KEYEVENT_UNCAUGHT = 0;
+
+    public int handleKeyEvent(KeyEvent event);
+}

core/res/res/values/config.xml

@@ -1100,6 +1100,12 @@
          legacy USB manager should be started. -->
     <string name="config_legacyUmsLunFile">/sys/devices/platform/usb_mass_storage/lun0/file</string>
 
+    <!-- Path to the library that contains a device specific key handler -->
+    <string name="config_deviceKeyHandlerLib" translatable="false"></string>
+
+    <!-- Name of that key handler class -->
+    <string name="config_deviceKeyHandlerClass" translatable="false"></string>
+
     <!-- If a dock provides a lid switch, that lid can be removed. This
          setting is used to determine, whether lidOpenRotation has to be
          applied. -->

core/res/res/values/symbols.xml

@@ -1840,6 +1840,8 @@
   <java-symbol type="bool" name="config_hasRemovableLid" />
   <java-symbol type="bool" name="config_hasDockBattery" />
   <java-symbol type="bool" name="config_noDelayInATwoDP" />
+  <java-symbol type="string" name="config_deviceKeyHandlerLib" />
+  <java-symbol type="string" name="config_deviceKeyHandlerClass" />
 
   <!-- Telephony -->
   <java-symbol type="bool" name="config_smsSamsungCdmaAlternateMessageIDEncoding" />

policy/src/com/android/internal/policy/impl/PhoneWindowManager.java

@@ -28,6 +28,7 @@
 import android.content.ComponentName;
 import android.content.ContentResolver;
 import android.content.Context;
+import android.content.ContextWrapper;
 import android.content.Intent;
 import android.content.IntentFilter;
 import android.content.ServiceConnection;
@@ -67,13 +68,16 @@
 
 import com.android.internal.R;
 import com.android.internal.app.ThemeUtils;
+import com.android.internal.os.DeviceKeyHandler;
 import com.android.internal.policy.PolicyManager;
 import com.android.internal.policy.impl.keyguard.KeyguardViewManager;
 import com.android.internal.policy.impl.keyguard.KeyguardViewMediator;
 import com.android.internal.statusbar.IStatusBarService;
 import com.android.internal.telephony.ITelephony;
 import com.android.internal.widget.PointerLocationView;
 
+import dalvik.system.DexClassLoader;
+
 import android.util.DisplayMetrics;
 import android.util.EventLog;
 import android.util.Log;
@@ -166,6 +170,7 @@
 import java.io.IOException;
 import java.io.PrintWriter;
 import java.util.List;
+import java.lang.reflect.Constructor;
 
 /**
  * WindowManagerPolicy implementation for the Android phone UI.  This
@@ -254,6 +259,8 @@ public class PhoneWindowManager implements WindowManagerPolicy {
                 KeyEvent.KEYCODE_CALCULATOR, Intent.CATEGORY_APP_CALCULATOR);
     }
 
+    DeviceKeyHandler mDeviceKeyHandler;
+
     /**
      * Lock protecting internal state.  Must not call out into window
      * manager with lock held.  (This lock will be acquired in places
@@ -1198,6 +1205,30 @@ public void init(Context context, IWindowManager windowManager,
         } else {
             screenTurnedOff(WindowManagerPolicy.OFF_BECAUSE_OF_USER);
         }
+
+        String deviceKeyHandlerLib = mContext.getResources().getString(
+                com.android.internal.R.string.config_deviceKeyHandlerLib);
+
+        String deviceKeyHandlerClass = mContext.getResources().getString(
+                com.android.internal.R.string.config_deviceKeyHandlerClass);
+
+        if (!deviceKeyHandlerLib.isEmpty() && !deviceKeyHandlerClass.isEmpty()) {
+            DexClassLoader loader =  new DexClassLoader(deviceKeyHandlerLib,
+                    new ContextWrapper(mContext).getCacheDir().getAbsolutePath(),
+                    null,
+                    ClassLoader.getSystemClassLoader());
+            try {
+                Class<?> klass = loader.loadClass(deviceKeyHandlerClass);
+                Constructor<?> constructor = klass.getConstructor(Context.class);
+                mDeviceKeyHandler = (DeviceKeyHandler) constructor.newInstance(
+                        mContext);
+                Slog.d(TAG, "Device key handler loaded");
+            } catch (Exception e) {
+                Slog.d(TAG, "Could not instantiate device key handler "
+                        + deviceKeyHandlerClass + " from class "
+                        + deviceKeyHandlerLib, e);
+            }
+        }
     }
 
     public void setInitialDisplaySize(Display display, int width, int height, int density) {
@@ -2496,6 +2527,14 @@ public long interceptKeyBeforeDispatching(WindowState win, KeyEvent event, int p
             return -1;
         }
 
+        if (mDeviceKeyHandler != null) {
+            try {
+                return mDeviceKeyHandler.handleKeyEvent(event);
+            } catch (Exception e) {
+                Slog.d(TAG, "Could not dispatch event to device key handler", e);
+            }
+        }
+
         // Let the application handle the key.
         return 0;
     }