Create a whitelist for use in Android platform

In order to reduce the startup impact to near zero, we are
creating a whitelist to be checked before parsing rules.

The whitelist will be shared over Global Settings. To generate
it, we will listen for intents at boot (LOCKED_BOOT_COMPLETED)
and when ANGLE itself has been updated (MY_PACKAGE_REPLACED).

The whitelist can also be populated by hand:

  adb shell settings put global angle_whitelist app1,app2,appN

We plan to further mitigate the ANGLE-enabled app impact
by parsing the full rules when creating the whitelist, off of
the critical path.

Bug: angleproject:3086
Test: Internal CTS tests and manual verification
Change-Id: I6263358e2fdbfaa7183d1b941005b5455285cbff
Reviewed-on: https://chromium-review.googlesource.com/c/1415715
Reviewed-by: Tim Van Patten <timvp@google.com>
Commit-Queue: Cody Northrop <cnorthrop@google.com>

android/AndroidManifest.xml.jinja2

@@ -10,6 +10,7 @@
           package="{{manifest_package|default('com.android.angle')}}">
 
     <uses-permission android:name="android.permission.WRITE_SECURE_SETTINGS" />
+    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
 
     <uses-sdk android:minSdkVersion="26"
               android:targetSdkVersion="28">
@@ -50,5 +51,14 @@
             <meta-data android:name="com.android.settings.order" android:value="100" />
             <meta-data android:name="com.android.settings.profile" android:value="primary_profile_only" />
         </activity>
+
+        <receiver android:name="com.android.angle.common.Receiver"
+                  android:directBootAware="true">
+            <intent-filter>
+                <action android:name="android.intent.action.LOCKED_BOOT_COMPLETED" />
+                <action android:name="android.intent.action.MY_PACKAGE_REPLACED" />
+            </intent-filter>
+        </receiver>
+
     </application>
 </manifest>

android/res/values/global_settings.xml

@@ -10,4 +10,5 @@
     <string name="global_settings_show_angle_in_use_dialog_box">show_angle_in_use_dialog_box</string>
     <string name="global_settings_driver_selection_pkgs">angle_gl_driver_selection_pkgs</string>
     <string name="global_settings_driver_selection_values">angle_gl_driver_selection_values</string>
+    <string name="global_settings_angle_whitelist">angle_whitelist</string>
 </resources>

android/src/com/android/angle/common/GlobalSettings.java

@@ -78,6 +78,13 @@ class GlobalSettings
                 showAngleInUseDialog ? 1 : 0);
     }
 
+    static void updateAngleWhitelist(Context context, String packageNames)
+    {
+        ContentResolver contentResolver = context.getContentResolver();
+        Settings.Global.putString(contentResolver,
+                context.getString(R.string.global_settings_angle_whitelist), packageNames);
+    }
+
     void updatePkg(String pkgName, String driver)
     {
         int pkgIndex = getGlobalSettingsPkgIndex(pkgName);

android/src/com/android/angle/common/Receiver.java

@@ -13,15 +13,98 @@ import android.content.SharedPreferences;
 import android.preference.PreferenceManager;
 import android.util.Log;
 
+import java.io.InputStream;
+import java.io.IOException;
+
+import org.json.JSONObject;
+import org.json.JSONArray;
+import org.json.JSONException;
+
 public class Receiver extends BroadcastReceiver
 {
 
-    private final static String TAG = Receiver.class.getSimpleName();
+    private final static String TAG = "AngleReceiver";
+    private final static String ANGLE_RULES_FILE = "a4a_rules.json";
 
     @Override
     public void onReceive(Context context, Intent intent)
     {
-        // Nothing to do yet...
+        Log.v(TAG, "Received intent, updating ANGLE whitelist...");
+
+        String jsonStr = loadRules(context);
+
+        String packageNames = parsePackageNames(jsonStr);
+
+        // Update the ANGLE whitelist
+        if (packageNames != null) {
+            GlobalSettings.updateAngleWhitelist(context, packageNames);
+        }
+    }
+
+    /*
+     * Open the rules file and pull all the JSON into a string
+     */
+    private String loadRules(Context context)
+    {
+        String jsonStr = null;
+
+        try {
+            InputStream rulesStream = context.getAssets().open(ANGLE_RULES_FILE);
+            int size = rulesStream.available();
+            byte[] buffer = new byte[size];
+            rulesStream.read(buffer);
+            rulesStream.close();
+            jsonStr = new String(buffer, "UTF-8");
+
+        } catch (IOException ioe) {
+            Log.e(TAG, "Failed to open " + ANGLE_RULES_FILE + ": ", ioe);
+        }
+
+        return jsonStr;
+    }
+
+    /*
+     * Extract all app package names from the json file and return them comma separated
+     */
+    private String parsePackageNames(String rulesJSON)
+    {
+        String packageNames = "";
+
+        try {
+            JSONObject jsonObj = new JSONObject(rulesJSON);
+            JSONArray rules = jsonObj.getJSONArray("Rules");
+            if (rules == null) {
+                Log.e(TAG, "No Rules in " + ANGLE_RULES_FILE);
+                return null;
+            }
+            for (int i = 0; i < rules.length(); i++) {
+                JSONObject rule = rules.getJSONObject(i);
+                JSONArray apps = rule.optJSONArray("Applications");
+                if (apps == null) {
+                    Log.v(TAG, "Skipping Rules entry with no Applications");
+                    continue;
+                }
+                for (int j = 0; j < apps.length(); j++) {
+                    JSONObject app = apps.optJSONObject(j);
+                    String appName = app.optString("AppName");
+                    if ((appName == null) || appName.isEmpty()) {
+                        Log.e(TAG, "Invalid AppName: '" + appName + "'");
+                    }
+                    if (packageNames.isEmpty()) {
+                        packageNames += appName;
+                    } else {
+                        packageNames += "," + appName;
+                    }
+                }
+            }
+            Log.v(TAG, "Parsed the following package names from " +
+                ANGLE_RULES_FILE + ": " + packageNames);
+        } catch (JSONException je) {
+            Log.e(TAG, "Error when parsing angle JSON: ", je);
+            return null;
+        }
+
+        return packageNames;
     }
 
     static void updateAllUseAngle(Context context)