gecko/mobile/android/base/EventDispatcher.java

286 lines
11 KiB
Java

/* 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.GeckoAppShell;
import org.mozilla.gecko.GeckoEvent;
import org.mozilla.gecko.mozglue.RobocopTarget;
import org.mozilla.gecko.util.EventCallback;
import org.mozilla.gecko.util.GeckoEventListener;
import org.mozilla.gecko.util.NativeEventListener;
import org.mozilla.gecko.util.NativeJSContainer;
import org.mozilla.gecko.util.NativeJSObject;
import org.json.JSONException;
import org.json.JSONObject;
import android.util.Log;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.CopyOnWriteArrayList;
@RobocopTarget
public final class EventDispatcher {
private static final String LOGTAG = "GeckoEventDispatcher";
private static final String GUID = "__guid__";
private static final String STATUS_CANCEL = "cancel";
private static final String STATUS_ERROR = "error";
private static final String STATUS_SUCCESS = "success";
private static final EventDispatcher INSTANCE = new EventDispatcher();
/**
* The capacity of a HashMap is rounded up to the next power-of-2. Every time the size
* of the map goes beyond 75% of the capacity, the map is rehashed. Therefore, to
* empirically determine the initial capacity that avoids rehashing, we need to
* determine the initial size, divide it by 75%, and round up to the next power-of-2.
*/
private static final int GECKO_NATIVE_EVENTS_COUNT = 0; // Default for HashMap
private static final int GECKO_JSON_EVENTS_COUNT = 256; // Empirically measured
private final Map<String, List<NativeEventListener>> mGeckoThreadNativeListeners =
new HashMap<String, List<NativeEventListener>>(GECKO_NATIVE_EVENTS_COUNT);
private final Map<String, List<GeckoEventListener>> mGeckoThreadJSONListeners =
new HashMap<String, List<GeckoEventListener>>(GECKO_JSON_EVENTS_COUNT);
public static EventDispatcher getInstance() {
return INSTANCE;
}
private EventDispatcher() {
}
private <T> void registerListener(final Class<? extends List<T>> listType,
final Map<String, List<T>> listenersMap,
final T listener,
final String[] events) {
try {
synchronized (listenersMap) {
for (final String event : events) {
List<T> listeners = listenersMap.get(event);
if (listeners == null) {
listeners = listType.newInstance();
listenersMap.put(event, listeners);
}
if (!AppConstants.RELEASE_BUILD && listeners.contains(listener)) {
throw new IllegalStateException("Already registered " + event);
}
listeners.add(listener);
}
}
} catch (final IllegalAccessException e) {
throw new IllegalArgumentException("Invalid new list type", e);
} catch (final InstantiationException e) {
throw new IllegalArgumentException("Invalid new list type", e);
}
}
private <T> void checkNotRegistered(final Map<String, List<T>> listenersMap,
final String[] events) {
synchronized (listenersMap) {
for (final String event: events) {
if (listenersMap.get(event) != null) {
throw new IllegalStateException(
"Already registered " + event + " under a different type");
}
}
}
}
private <T> void unregisterListener(final Map<String, List<T>> listenersMap,
final T listener,
final String[] events) {
synchronized (listenersMap) {
for (final String event : events) {
List<T> listeners = listenersMap.get(event);
if ((listeners == null ||
!listeners.remove(listener)) && !AppConstants.RELEASE_BUILD) {
throw new IllegalArgumentException(event + " was not registered");
}
}
}
}
@SuppressWarnings("unchecked")
public void registerGeckoThreadListener(final NativeEventListener listener,
final String... events) {
checkNotRegistered(mGeckoThreadJSONListeners, events);
// For listeners running on the Gecko thread, we want to notify the listeners
// outside of our synchronized block, because the listeners may take an
// indeterminate amount of time to run. Therefore, to ensure concurrency when
// iterating the list outside of the synchronized block, we use a
// CopyOnWriteArrayList.
registerListener((Class)CopyOnWriteArrayList.class,
mGeckoThreadNativeListeners, listener, events);
}
@Deprecated // Use NativeEventListener instead
@SuppressWarnings("unchecked")
public void registerGeckoThreadListener(final GeckoEventListener listener,
final String... events) {
checkNotRegistered(mGeckoThreadNativeListeners, events);
registerListener((Class)CopyOnWriteArrayList.class,
mGeckoThreadJSONListeners, listener, events);
}
public void unregisterGeckoThreadListener(final NativeEventListener listener,
final String... events) {
unregisterListener(mGeckoThreadNativeListeners, listener, events);
}
@Deprecated // Use NativeEventListener instead
public void unregisterGeckoThreadListener(final GeckoEventListener listener,
final String... events) {
unregisterListener(mGeckoThreadJSONListeners, listener, events);
}
public void dispatchEvent(final NativeJSContainer message) {
// First try native listeners.
final String type = message.optString("type", null);
if (type == null) {
Log.e(LOGTAG, "JSON message must have a type property");
return;
}
final List<NativeEventListener> listeners;
synchronized (mGeckoThreadNativeListeners) {
listeners = mGeckoThreadNativeListeners.get(type);
}
final String guid = message.optString(GUID, null);
EventCallback callback = null;
if (guid != null) {
callback = new GeckoEventCallback(guid, type);
}
if (listeners != null) {
if (listeners.size() == 0) {
Log.w(LOGTAG, "No listeners for " + type);
}
try {
for (final NativeEventListener listener : listeners) {
listener.handleMessage(type, message, callback);
}
} catch (final NativeJSObject.InvalidPropertyException e) {
Log.e(LOGTAG, "Exception occurred while handling " + type, e);
}
// If we found native listeners, we assume we don't have any JSON listeners
// and return early. This assumption is checked when registering listeners.
return;
}
try {
// If we didn't find native listeners, try JSON listeners.
dispatchEvent(new JSONObject(message.toString()), callback);
} catch (final JSONException e) {
Log.e(LOGTAG, "Cannot parse JSON", e);
} catch (final UnsupportedOperationException e) {
Log.e(LOGTAG, "Cannot convert message to JSON", e);
}
}
public void dispatchEvent(final JSONObject message, final EventCallback callback) {
// {
// "type": "value",
// "event_specific": "value",
// ...
try {
final String type = message.getString("type");
List<GeckoEventListener> listeners;
synchronized (mGeckoThreadJSONListeners) {
listeners = mGeckoThreadJSONListeners.get(type);
}
if (listeners == null || listeners.size() == 0) {
Log.w(LOGTAG, "No listeners for " + type);
// If there are no listeners, cancel the callback to prevent Gecko-side observers
// from being leaked.
if (callback != null) {
callback.sendCancel();
}
return;
}
for (final GeckoEventListener listener : listeners) {
listener.handleMessage(type, message);
}
} catch (final JSONException e) {
Log.e(LOGTAG, "handleGeckoMessage throws " + e, e);
}
}
@RobocopTarget
@Deprecated
public static void sendResponse(JSONObject message, Object response) {
sendResponseHelper(STATUS_SUCCESS, message, response);
}
@Deprecated
public static void sendError(JSONObject message, Object response) {
sendResponseHelper(STATUS_ERROR, message, response);
}
@Deprecated
private static void sendResponseHelper(String status, JSONObject message, Object response) {
try {
final JSONObject wrapper = new JSONObject();
wrapper.put(GUID, message.getString(GUID));
wrapper.put("status", status);
wrapper.put("response", response);
GeckoAppShell.sendEventToGecko(GeckoEvent.createBroadcastEvent(
message.getString("type") + ":Response", wrapper.toString()));
} catch (final JSONException e) {
Log.e(LOGTAG, "Unable to send response", e);
}
}
private static class GeckoEventCallback implements EventCallback {
private final String guid;
private final String type;
private boolean sent;
public GeckoEventCallback(final String guid, final String type) {
this.guid = guid;
this.type = type;
}
public void sendSuccess(final Object response) {
sendResponse(STATUS_SUCCESS, response);
}
public void sendError(final Object response) {
sendResponse(STATUS_ERROR, response);
}
public void sendCancel() {
sendResponse(STATUS_CANCEL, null);
}
private void sendResponse(final String status, final Object response) {
if (sent) {
throw new IllegalStateException("Callback has already been executed for type=" +
type + ", guid=" + guid);
}
sent = true;
try {
final JSONObject wrapper = new JSONObject();
wrapper.put(GUID, guid);
wrapper.put("status", status);
wrapper.put("response", response);
GeckoAppShell.sendEventToGecko(GeckoEvent.createBroadcastEvent(type + ":Response",
wrapper.toString()));
} catch (final JSONException e) {
Log.e(LOGTAG, "Unable to send response for: " + type, e);
}
}
}
}