Add system API to watch for permission changes

Change-Id: I1ce450a59fb326c14848f46732d877dea33f33c7
diff --git a/core/java/android/app/ApplicationPackageManager.java b/core/java/android/app/ApplicationPackageManager.java
index 41e3db8..cb1e7aa 100644
--- a/core/java/android/app/ApplicationPackageManager.java
+++ b/core/java/android/app/ApplicationPackageManager.java
@@ -31,6 +31,7 @@
 import android.content.pm.ComponentInfo;
 import android.content.pm.ContainerEncryptionParams;
 import android.content.pm.FeatureInfo;
+import android.content.pm.IOnPermissionsChangeListener;
 import android.content.pm.IPackageDataObserver;
 import android.content.pm.IPackageDeleteObserver;
 import android.content.pm.IPackageInstallObserver;
@@ -88,6 +89,7 @@
 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Map;
 import java.util.Objects;
 
 /*package*/
@@ -1048,6 +1050,38 @@
         }
     }
 
+    @Override
+    public void addOnPermissionsChangeListener(OnPermissionsChangedListener listener) {
+        synchronized (mPermissionListeners) {
+            if (mPermissionListeners.get(listener) != null) {
+                return;
+            }
+            OnPermissionsChangeListenerDelegate delegate =
+                    new OnPermissionsChangeListenerDelegate(listener, Looper.getMainLooper());
+            try {
+                mPM.addOnPermissionsChangeListener(delegate);
+                mPermissionListeners.put(listener, delegate);
+            } catch (RemoteException e) {
+                throw new RuntimeException("Package manager has died", e);
+            }
+        }
+    }
+
+    @Override
+    public void removeOnPermissionsChangeListener(OnPermissionsChangedListener listener) {
+        synchronized (mPermissionListeners) {
+            IOnPermissionsChangeListener delegate = mPermissionListeners.get(listener);
+            if (delegate != null) {
+                try {
+                    mPM.removeOnPermissionsChangeListener(delegate);
+                    mPermissionListeners.remove(listener);
+                } catch (RemoteException e) {
+                    throw new RuntimeException("Package manager has died", e);
+                }
+            }
+        }
+    }
+
     static void configurationChanged() {
         synchronized (sSync) {
             sIconCache.clear();
@@ -2139,4 +2173,39 @@
             = new ArrayMap<ResourceName, WeakReference<Drawable.ConstantState>>();
     private static ArrayMap<ResourceName, WeakReference<CharSequence>> sStringCache
             = new ArrayMap<ResourceName, WeakReference<CharSequence>>();
+
+    private final Map<OnPermissionsChangedListener, IOnPermissionsChangeListener>
+            mPermissionListeners = new ArrayMap<>();
+
+    public class OnPermissionsChangeListenerDelegate extends IOnPermissionsChangeListener.Stub
+            implements Handler.Callback{
+        private static final int MSG_PERMISSIONS_CHANGED = 1;
+
+        private final OnPermissionsChangedListener mListener;
+        private final Handler mHandler;
+
+
+        public OnPermissionsChangeListenerDelegate(OnPermissionsChangedListener listener,
+                Looper looper) {
+            mListener = listener;
+            mHandler = new Handler(looper, this);
+        }
+
+        @Override
+        public void onPermissionsChanged(int uid) {
+            mHandler.obtainMessage(MSG_PERMISSIONS_CHANGED, uid, 0).sendToTarget();
+        }
+
+        @Override
+        public boolean handleMessage(Message msg) {
+            switch (msg.what) {
+                case MSG_PERMISSIONS_CHANGED: {
+                    final int uid = msg.arg1;
+                    mListener.onPermissionsChanged(uid);
+                    return true;
+                }
+            }
+            return false;
+        }
+    }
 }
diff --git a/core/java/android/content/pm/IOnPermissionsChangeListener.aidl b/core/java/android/content/pm/IOnPermissionsChangeListener.aidl
new file mode 100644
index 0000000..7791b50
--- /dev/null
+++ b/core/java/android/content/pm/IOnPermissionsChangeListener.aidl
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2015 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.content.pm;
+
+/**
+ * Listener for changes in the permissions for installed packages.
+ * {@hide}
+ */
+oneway interface IOnPermissionsChangeListener {
+    void onPermissionsChanged(int uid);
+}
diff --git a/core/java/android/content/pm/IPackageManager.aidl b/core/java/android/content/pm/IPackageManager.aidl
index 00b8c71..0c07bc3 100644
--- a/core/java/android/content/pm/IPackageManager.aidl
+++ b/core/java/android/content/pm/IPackageManager.aidl
@@ -31,6 +31,7 @@
 import android.content.pm.IPackageDataObserver;
 import android.content.pm.IPackageMoveObserver;
 import android.content.pm.IPackageStatsObserver;
+import android.content.pm.IOnPermissionsChangeListener;
 import android.content.pm.IntentFilterVerificationInfo;
 import android.content.pm.InstrumentationInfo;
 import android.content.pm.KeySet;
@@ -490,4 +491,7 @@
     KeySet getSigningKeySet(String packageName);
     boolean isPackageSignedByKeySet(String packageName, in KeySet ks);
     boolean isPackageSignedByKeySetExactly(String packageName, in KeySet ks);
+
+    void addOnPermissionsChangeListener(in IOnPermissionsChangeListener listener);
+    void removeOnPermissionsChangeListener(in IOnPermissionsChangeListener listener);
 }
diff --git a/core/java/android/content/pm/PackageManager.java b/core/java/android/content/pm/PackageManager.java
index c016ac3..c816971 100644
--- a/core/java/android/content/pm/PackageManager.java
+++ b/core/java/android/content/pm/PackageManager.java
@@ -16,11 +16,13 @@
 
 package android.content.pm;
 
+import android.Manifest;
 import android.annotation.CheckResult;
 import android.annotation.DrawableRes;
 import android.annotation.IntDef;
 import android.annotation.NonNull;
 import android.annotation.Nullable;
+import android.annotation.RequiresPermission;
 import android.annotation.SdkConstant;
 import android.annotation.SdkConstant.SdkConstantType;
 import android.annotation.StringRes;
@@ -78,6 +80,21 @@
     }
 
     /**
+     * Listener for changes in permissions granted to a UID.
+     *
+     * @hide
+     */
+    @SystemApi
+    public interface OnPermissionsChangedListener {
+
+        /**
+         * Called when the permissions for a UID change.
+         * @param uid The UID with a change.
+         */
+        public void onPermissionsChanged(int uid);
+    }
+
+    /**
      * {@link PackageInfo} flag: return information about
      * activities in the package in {@link PackageInfo#activities}.
      */
@@ -4292,6 +4309,27 @@
     public abstract boolean isSafeMode();
 
     /**
+     * Adds a listener for permission changes for installed packages.
+     *
+     * @param listener The listener to add.
+     *
+     * @hide
+     */
+    @SystemApi
+    @RequiresPermission(Manifest.permission.OBSERVE_GRANT_REVOKE_PERMISSIONS)
+    public abstract void addOnPermissionsChangeListener(OnPermissionsChangedListener listener);
+
+    /**
+     * Remvoes a listener for permission changes for installed packages.
+     *
+     * @param listener The listener to remove.
+     *
+     * @hide
+     */
+    @SystemApi
+    public abstract void removeOnPermissionsChangeListener(OnPermissionsChangedListener listener);
+
+    /**
      * Return the {@link KeySet} associated with the String alias for this
      * application.
      *
diff --git a/core/java/android/os/RemoteCallbackList.java b/core/java/android/os/RemoteCallbackList.java
index d2a9cdc..5849350 100644
--- a/core/java/android/os/RemoteCallbackList.java
+++ b/core/java/android/os/RemoteCallbackList.java
@@ -77,7 +77,6 @@
     public boolean register(E callback) {
         return register(callback, null);
     }
-    
     /**
      * Add a new callback to the list.  This callback will remain in the list
      * until a corresponding call to {@link #unregister} or its hosting process
diff --git a/core/res/AndroidManifest.xml b/core/res/AndroidManifest.xml
index 709de9e..0911d42 100644
--- a/core/res/AndroidManifest.xml
+++ b/core/res/AndroidManifest.xml
@@ -1979,6 +1979,10 @@
     <permission android:name="android.permission.GRANT_REVOKE_PERMISSIONS"
         android:protectionLevel="signature" />
 
+    <!-- @hide Allows an application to observe permission changes. -->
+    <permission android:name="android.permission.OBSERVE_GRANT_REVOKE_PERMISSIONS"
+        android:protectionLevel="signatureOrSystem" />
+
     <!-- Allows an application to use SurfaceFlinger's low level features.
     <p>Not for use by third-party applications. -->
     <permission android:name="android.permission.ACCESS_SURFACE_FLINGER"