/*
* Copyright (C) 2006 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.webkit;
import android.os.Handler;
import android.os.Message;
import android.graphics.Bitmap;
import java.util.Vector;
/**
* Functions for manipulating the icon database used by WebView.
* These functions require that a WebView be constructed before being invoked
* and WebView.getIconDatabase() will return a WebIconDatabase object. This
* WebIconDatabase object is a single instance and all methods operate on that
* single object.
*/
public final class WebIconDatabase {
// Global instance of a WebIconDatabase
private static WebIconDatabase sIconDatabase;
// EventHandler for handling messages before and after the WebCore thread is
// ready.
private final EventHandler mEventHandler = new EventHandler();
// Class to handle messages before WebCore is ready
private class EventHandler extends Handler {
// Message ids
static final int OPEN = 0;
static final int CLOSE = 1;
static final int REMOVE_ALL = 2;
static final int REQUEST_ICON = 3;
static final int RETAIN_ICON = 4;
static final int RELEASE_ICON = 5;
// Message for dispatching icon request results
private static final int ICON_RESULT = 10;
// Actual handler that runs in WebCore thread
private Handler mHandler;
// Vector of messages before the WebCore thread is ready
private Vector<Message> mMessages = new Vector<Message>();
// Class to handle a result dispatch
private class IconResult {
private final String mUrl;
private final Bitmap mIcon;
private final IconListener mListener;
IconResult(String url, Bitmap icon, IconListener l) {
mUrl = url;
mIcon = icon;
mListener = l;
}
void dispatch() {
mListener.onReceivedIcon(mUrl, mIcon);
}
}
@Override
public void handleMessage(Message msg) {
// Note: This is the message handler for the UI thread.
switch (msg.what) {
case ICON_RESULT:
((IconResult) msg.obj).dispatch();
break;
}
}
// Called by WebCore thread to create the actual handler
private synchronized void createHandler() {
if (mHandler == null) {
mHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
// Note: This is the message handler for the WebCore
// thread.
switch (msg.what) {
case OPEN:
nativeOpen((String) msg.obj);
break;
case CLOSE:
nativeClose();
break;
case REMOVE_ALL:
nativeRemoveAllIcons();
break;
case REQUEST_ICON:
IconListener l = (IconListener) msg.obj;
String url = msg.getData().getString("url");
Bitmap icon = nativeIconForPageUrl(url);
if (icon != null) {
EventHandler.this.sendMessage(
Message.obtain(null, ICON_RESULT,
new IconResult(url, icon, l)));
}
break;
case RETAIN_ICON:
nativeRetainIconForPageUrl((String) msg.obj);
break;
case RELEASE_ICON:
nativeReleaseIconForPageUrl((String) msg.obj);
break;
}
}
};
// Transfer all pending messages
for (int size = mMessages.size(); size > 0; size--) {
mHandler.sendMessage(mMessages.remove(0));
}
mMessages = null;
}
}
private synchronized void postMessage(Message msg) {
if (mMessages != null) {
mMessages.add(msg);
} else {
mHandler.sendMessage(msg);
}
}
}
/**
* Interface for receiving icons from the database.
*/
public interface IconListener {
/**
* Called when the icon has been retrieved from the database and the
* result is non-null.
* @param url The url passed in the request.
* @param icon The favicon for the given url.
*/
public void onReceivedIcon(String url, Bitmap icon);
}
/**
* Open a the icon database and store the icons in the given path.
* @param path The directory path where the icon database will be stored.
* @return True if the database was successfully opened or created in
* the given path.
*/
public void open(String path) {
if (path != null) {
mEventHandler.postMessage(
Message.obtain(null, EventHandler.OPEN, path));
}
}
/**
* Close the shared instance of the icon database.
*/
public void close() {
mEventHandler.postMessage(
Message.obtain(null, EventHandler.CLOSE));
}
/**
* Removes all the icons in the database.
*/
public void removeAllIcons() {
mEventHandler.postMessage(
Message.obtain(null, EventHandler.REMOVE_ALL));
}
/**
* Request the Bitmap representing the icon for the given page
* url. If the icon exists, the listener will be called with the result.
* @param url The page's url.
* @param listener An implementation on IconListener to receive the result.
*/
public void requestIconForPageUrl(String url, IconListener listener) {
if (listener == null || url == null) {
return;
}
Message msg = Message.obtain(null, EventHandler.REQUEST_ICON, listener);
msg.getData().putString("url", url);
mEventHandler.postMessage(msg);
}
/**
* Retain the icon for the given page url.
* @param url The page's url.
*/
public void retainIconForPageUrl(String url) {
if (url != null) {
mEventHandler.postMessage(
Message.obtain(null, EventHandler.RETAIN_ICON, url));
}
}
/**
* Release the icon for the given page url.
* @param url The page's url.
*/
public void releaseIconForPageUrl(String url) {
if (url != null) {
mEventHandler.postMessage(
Message.obtain(null, EventHandler.RELEASE_ICON, url));
}
}
/**
* Get the global instance of WebIconDatabase.
* @return A single instance of WebIconDatabase. It will be the same
* instance for the current process each time this method is
* called.
*/
public static WebIconDatabase getInstance() {
// XXX: Must be created in the UI thread.
if (sIconDatabase == null) {
sIconDatabase = new WebIconDatabase();
}
return sIconDatabase;
}
/**
* Create the internal handler and transfer all pending messages.
* XXX: Called by WebCore thread only!
*/
/*package*/ void createHandler() {
mEventHandler.createHandler();
}
/**
* Private constructor to avoid anyone else creating an instance.
*/
private WebIconDatabase() {}
// Native functions
private static native void nativeOpen(String path);
private static native void nativeClose();
private static native void nativeRemoveAllIcons();
private static native Bitmap nativeIconForPageUrl(String url);
private static native void nativeRetainIconForPageUrl(String url);
private static native void nativeReleaseIconForPageUrl(String url);
}