The Tor Browser: mobile/android/base/JavaAddonManager.java@b8a032363ba2 (annotated)

mobile/android/base/JavaAddonManager.java@b8a032363ba2 (annotated)

mobile/android/base/JavaAddonManager.java

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* -*- Mode: Java; c-basic-offset: 4; tab-width: 4; indent-tabs-mode: nil; -*-
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 package org.mozilla.gecko;
 import org.mozilla.gecko.util.GeckoEventListener;
 import org.json.JSONException;
 import org.json.JSONObject;
 import android.content.Context;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.Message;
 import android.util.Log;
 import dalvik.system.DexClassLoader;
 import java.io.File;
 import java.lang.reflect.Constructor;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;
 /**
  * The manager for addon-provided Java code.
  *
  * Java code in addons can be loaded using the Dex:Load message, and unloaded
  * via the Dex:Unload message. Addon classes loaded are checked for a constructor
  * that takes a Map&lt;String, Handler.Callback&gt;. If such a constructor
  * exists, it is called and the objects populated into the map by the constructor
  * are registered as event listeners. If no such constructor exists, the default
  * constructor is invoked instead.
  *
  * Note: The Map and Handler.Callback classes were used in this API definition
  * rather than defining a custom class. This was done explicitly so that the
  * addon code can be compiled against the android.jar provided in the Android
  * SDK, rather than having to be compiled against Fennec source code.
  *
  * The Handler.Callback instances provided (as described above) are inovked with
  * Message objects when the corresponding events are dispatched. The Bundle
  * object attached to the Message will contain the "primitive" values from the
  * JSON of the event. ("primitive" includes bool/int/long/double/String). If
  * the addon callback wishes to synchronously return a value back to the event
  * dispatcher, they can do so by inserting the response string into the bundle
  * under the key "response".
  */
 class JavaAddonManager implements GeckoEventListener {
     private static final String LOGTAG = "GeckoJavaAddonManager";
     private static JavaAddonManager sInstance;
     private final EventDispatcher mDispatcher;
     private final Map<String, Map<String, GeckoEventListener>> mAddonCallbacks;
     private Context mApplicationContext;
     public static JavaAddonManager getInstance() {
         if (sInstance == null) {
             sInstance = new JavaAddonManager();
         }
         return sInstance;
     }
     private JavaAddonManager() {
         mDispatcher = GeckoAppShell.getEventDispatcher();
         mAddonCallbacks = new HashMap<String, Map<String, GeckoEventListener>>();
     }
     void init(Context applicationContext) {
         if (mApplicationContext != null) {
             // we've already done this registration. don't do it again
             return;
         }
         mApplicationContext = applicationContext;
         mDispatcher.registerEventListener("Dex:Load", this);
         mDispatcher.registerEventListener("Dex:Unload", this);
     }
     @Override
     public void handleMessage(String event, JSONObject message) {
         try {
             if (event.equals("Dex:Load")) {
                 String zipFile = message.getString("zipfile");
                 String implClass = message.getString("impl");
                 Log.d(LOGTAG, "Attempting to load classes.dex file from " + zipFile + " and instantiate " + implClass);
                 try {
                     File tmpDir = mApplicationContext.getDir("dex", 0);
                     DexClassLoader loader = new DexClassLoader(zipFile, tmpDir.getAbsolutePath(), null, mApplicationContext.getClassLoader());
                     Class<?> c = loader.loadClass(implClass);
                     try {
                         Constructor<?> constructor = c.getDeclaredConstructor(Map.class);
                         Map<String, Handler.Callback> callbacks = new HashMap<String, Handler.Callback>();
                         constructor.newInstance(callbacks);
                         registerCallbacks(zipFile, callbacks);
                     } catch (NoSuchMethodException nsme) {
                         Log.d(LOGTAG, "Did not find constructor with parameters Map<String, Handler.Callback>. Falling back to default constructor...");
                         // fallback for instances with no constructor that takes a Map<String, Handler.Callback>
                         c.newInstance();
                     }
                 } catch (Exception e) {
                     Log.e(LOGTAG, "Unable to load dex successfully", e);
                 }
             } else if (event.equals("Dex:Unload")) {
                 String zipFile = message.getString("zipfile");
                 unregisterCallbacks(zipFile);
             }
         } catch (JSONException e) {
             Log.e(LOGTAG, "Exception handling message [" + event + "]:", e);
         }
     }
     private void registerCallbacks(String zipFile, Map<String, Handler.Callback> callbacks) {
         Map<String, GeckoEventListener> addonCallbacks = mAddonCallbacks.get(zipFile);
         if (addonCallbacks != null) {
             Log.w(LOGTAG, "Found pre-existing callbacks for zipfile [" + zipFile + "]; aborting re-registration!");
             return;
         }
         addonCallbacks = new HashMap<String, GeckoEventListener>();
         for (String event : callbacks.keySet()) {
             CallbackWrapper wrapper = new CallbackWrapper(callbacks.get(event));
             mDispatcher.registerEventListener(event, wrapper);
             addonCallbacks.put(event, wrapper);
         }
         mAddonCallbacks.put(zipFile, addonCallbacks);
     }
     private void unregisterCallbacks(String zipFile) {
         Map<String, GeckoEventListener> callbacks = mAddonCallbacks.remove(zipFile);
         if (callbacks == null) {
             Log.w(LOGTAG, "Attempting to unregister callbacks from zipfile [" + zipFile + "] which has no callbacks registered.");
             return;
         }
         for (String event : callbacks.keySet()) {
             mDispatcher.unregisterEventListener(event, callbacks.get(event));
         }
     }
     private static class CallbackWrapper implements GeckoEventListener {
         private final Handler.Callback mDelegate;
         private Bundle mBundle;
         CallbackWrapper(Handler.Callback delegate) {
             mDelegate = delegate;
         }
         private Bundle jsonToBundle(JSONObject json) {
             // XXX right now we only support primitive types;
             // we don't recurse down into JSONArray or JSONObject instances
             Bundle b = new Bundle();
             for (Iterator<?> keys = json.keys(); keys.hasNext(); ) {
                 try {
                     String key = (String)keys.next();
                     Object value = json.get(key);
                     if (value instanceof Integer) {
                         b.putInt(key, (Integer)value);
                     } else if (value instanceof String) {
                         b.putString(key, (String)value);
                     } else if (value instanceof Boolean) {
                         b.putBoolean(key, (Boolean)value);
                     } else if (value instanceof Long) {
                         b.putLong(key, (Long)value);
                     } else if (value instanceof Double) {
                         b.putDouble(key, (Double)value);
                     }
                 } catch (JSONException e) {
                     Log.d(LOGTAG, "Error during JSON->bundle conversion", e);
                 }
             }
             return b;
         }
         @Override
         public void handleMessage(String event, JSONObject json) {
             try {
                 if (mBundle != null) {
                     Log.w(LOGTAG, "Event [" + event + "] handler is re-entrant; response messages may be lost");
                 }
                 mBundle = jsonToBundle(json);
                 Message msg = new Message();
                 msg.setData(mBundle);
                 mDelegate.handleMessage(msg);
                 JSONObject obj = new JSONObject();
                 obj.put("response", mBundle.getString("response"));
                 EventDispatcher.sendResponse(json, obj);
                 mBundle = null;
             } catch (Exception e) {
                 Log.e(LOGTAG, "Caught exception thrown from wrapped addon message handler", e);
             }
         }
     }
 }

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mobile/android/base/JavaAddonManager.java@b8a032363ba2 (annotated)

mobile/android/base/JavaAddonManager.java