| /* |
| * 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 com.android.car.audio; |
| |
| import android.car.Car; |
| import android.car.media.CarAudioManager; |
| import android.content.pm.PackageManager; |
| import android.hardware.automotive.audiocontrol.V1_0.ContextNumber; |
| import android.media.AudioAttributes; |
| import android.media.AudioFocusInfo; |
| import android.media.AudioManager; |
| import android.media.audiopolicy.AudioPolicy; |
| import android.os.Bundle; |
| import android.util.Log; |
| |
| import java.io.PrintWriter; |
| import java.util.ArrayList; |
| import java.util.HashMap; |
| import java.util.Iterator; |
| |
| |
| public class CarAudioFocus extends AudioPolicy.AudioPolicyFocusListener { |
| |
| private static final String TAG = "CarAudioFocus"; |
| |
| private final AudioManager mAudioManager; |
| private final PackageManager mPackageManager; |
| private CarAudioService mCarAudioService; // Dynamically assigned just after construction |
| private AudioPolicy mAudioPolicy; // Dynamically assigned just after construction |
| |
| |
| // Values for the internal interaction matrix we use to make focus decisions |
| static final int INTERACTION_REJECT = 0; // Focus not granted |
| static final int INTERACTION_EXCLUSIVE = 1; // Focus granted, others loose focus |
| static final int INTERACTION_CONCURRENT = 2; // Focus granted, others keep focus |
| |
| // TODO: Make this an overlayable resource... |
| // MUSIC = 1, // Music playback |
| // NAVIGATION = 2, // Navigation directions |
| // VOICE_COMMAND = 3, // Voice command session |
| // CALL_RING = 4, // Voice call ringing |
| // CALL = 5, // Voice call |
| // ALARM = 6, // Alarm sound from Android |
| // NOTIFICATION = 7, // Notifications |
| // SYSTEM_SOUND = 8, // User interaction sounds (button clicks, etc) |
| private static int sInteractionMatrix[][] = { |
| // Row selected by playing sound (labels along the right) |
| // Column selected by incoming request (labels along the top) |
| // Cell value is one of INTERACTION_REJECT, INTERACTION_EXCLUSIVE, INTERACTION_CONCURRENT |
| // Invalid, Music, Nav, Voice, Ring, Call, Alarm, Notification, System |
| { 0, 0, 0, 0, 0, 0, 0, 0, 0 }, // Invalid |
| { 0, 1, 2, 1, 1, 1, 1, 2, 2 }, // Music |
| { 0, 2, 2, 1, 2, 1, 2, 2, 2 }, // Nav |
| { 0, 2, 0, 2, 1, 1, 0, 0, 0 }, // Voice |
| { 0, 0, 2, 2, 2, 2, 0, 0, 2 }, // Ring |
| { 0, 0, 2, 0, 2, 2, 2, 2, 0 }, // Context |
| { 0, 2, 2, 1, 1, 1, 2, 2, 2 }, // Alarm |
| { 0, 2, 2, 1, 1, 1, 2, 2, 2 }, // Notification |
| { 0, 2, 2, 1, 1, 1, 2, 2, 2 }, // System |
| }; |
| |
| |
| private class FocusEntry { |
| // Requester info |
| final AudioFocusInfo mAfi; // never null |
| |
| final int mAudioContext; // Which HAL level context does this affect |
| final ArrayList<FocusEntry> mBlockers; // List of requests that block ours |
| boolean mReceivedLossTransientCanDuck; // Whether holder has lost focus duckably |
| |
| FocusEntry(AudioFocusInfo afi, |
| int context) { |
| mAfi = afi; |
| mAudioContext = context; |
| mBlockers = new ArrayList<FocusEntry>(); |
| } |
| |
| public String getClientId() { |
| return mAfi.getClientId(); |
| } |
| |
| public boolean wantsPauseInsteadOfDucking() { |
| return (mAfi.getFlags() & AudioManager.AUDIOFOCUS_FLAG_PAUSES_ON_DUCKABLE_LOSS) != 0; |
| } |
| |
| public boolean receivesDuckEvents() { |
| Bundle bundle = mAfi.getAttributes().getBundle(); |
| |
| if (bundle == null) { |
| return false; |
| } |
| |
| if (!bundle.getBoolean(CarAudioManager.AUDIOFOCUS_EXTRA_RECEIVE_DUCKING_EVENTS)) { |
| return false; |
| } |
| |
| return (mPackageManager.checkPermission( |
| Car.PERMISSION_RECEIVE_CAR_AUDIO_DUCKING_EVENTS, |
| mAfi.getPackageName()) |
| == PackageManager.PERMISSION_GRANTED); |
| } |
| } |
| |
| |
| // We keep track of all the focus requesters in this map, with their clientId as the key. |
| // This is used both for focus dispatch and death handling |
| // Note that the clientId reflects the AudioManager instance and listener object (if any) |
| // so that one app can have more than one unique clientId by setting up distinct listeners. |
| // Because the listener gets only LOSS/GAIN messages, this is important for an app to do if |
| // it expects to request focus concurrently for different USAGEs so it knows which USAGE |
| // gained or lost focus at any given moment. If the SAME listener is used for requests of |
| // different USAGE while the earlier request is still in the focus stack (whether holding |
| // focus or pending), the new request will be REJECTED so as to avoid any confusion about |
| // the meaning of subsequent GAIN/LOSS events (which would continue to apply to the focus |
| // request that was already active or pending). |
| private final HashMap<String, FocusEntry> mFocusHolders = new HashMap<>(); |
| private final HashMap<String, FocusEntry> mFocusLosers = new HashMap<>(); |
| |
| |
| CarAudioFocus(AudioManager audioManager, PackageManager packageManager) { |
| mAudioManager = audioManager; |
| mPackageManager = packageManager; |
| } |
| |
| |
| // This has to happen after the construction to avoid a chicken and egg problem when setting up |
| // the AudioPolicy which must depend on this object. |
| public void setOwningPolicy(CarAudioService audioService, AudioPolicy parentPolicy) { |
| mCarAudioService = audioService; |
| mAudioPolicy = parentPolicy; |
| } |
| |
| |
| // This sends a focus loss message to the targeted requester. |
| private void sendFocusLoss(FocusEntry loser, int lossType) { |
| Log.i(TAG, "sendFocusLoss (" + focusEventToString(lossType) + ") to " |
| + loser.getClientId()); |
| int result = mAudioManager.dispatchAudioFocusChange(loser.mAfi, lossType, mAudioPolicy); |
| if (result != AudioManager.AUDIOFOCUS_REQUEST_GRANTED) { |
| // TODO: Is this actually an error, or is it okay for an entry in the focus stack |
| // to NOT have a listener? If that's the case, should we even keep it in the focus |
| // stack? |
| Log.e(TAG, "Failure to signal loss of audio focus with error: " + result); |
| } |
| } |
| |
| |
| /** @see AudioManager#requestAudioFocus(AudioManager.OnAudioFocusChangeListener, int, int, int) */ |
| // Note that we replicate most, but not all of the behaviors of the default MediaFocusControl |
| // engine as of Android P. |
| // Besides the interaction matrix which allows concurrent focus for multiple requestors, which |
| // is the reason for this module, we also treat repeated requests from the same clientId |
| // slightly differently. |
| // If a focus request for the same listener (clientId) is received while that listener is |
| // already in the focus stack, we REJECT it outright unless it is for the same USAGE. |
| // If it is for the same USAGE, we replace the old request with the new one. |
| // The default audio framework's behavior is to remove the previous entry in the stack (no-op |
| // if the requester is already holding focus). |
| int evaluateFocusRequest(AudioFocusInfo afi) { |
| Log.i(TAG, "Evaluating " + focusEventToString(afi.getGainRequest()) + " request for client " |
| + afi.getClientId()); |
| |
| // Is this a request for premanant focus? |
| // AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE -- Means Notifications should be denied |
| // AUDIOFOCUS_GAIN_TRANSIENT -- Means current focus holders should get transient loss |
| // AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK -- Means other can duck (no loss message from us) |
| // NOTE: We expect that in practice it will be permanent for all media requests and |
| // transient for everything else, but that isn't currently an enforced requirement. |
| final boolean permanent = |
| (afi.getGainRequest() == AudioManager.AUDIOFOCUS_GAIN); |
| final boolean allowDucking = |
| (afi.getGainRequest() == AudioManager.AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK); |
| |
| |
| // Convert from audio attributes "usage" to HAL level "context" |
| final int requestedContext = mCarAudioService.getContextForUsage( |
| afi.getAttributes().getUsage()); |
| |
| // If we happen to find entries that this new request should replace, we'll store them here. |
| // This happens when a client makes a second AF request on the same listener. |
| // After we've granted audio focus to our current request, we'll abandon these requests. |
| FocusEntry replacedCurrentEntry = null; |
| FocusEntry replacedBlockedEntry = null; |
| |
| // Scan all active and pending focus requests. If any should cause rejection of |
| // this new request, then we're done. Keep a list of those against whom we're exclusive |
| // so we can update the relationships if/when we are sure we won't get rejected. |
| Log.i(TAG, "Scanning focus holders..."); |
| final ArrayList<FocusEntry> losers = new ArrayList<FocusEntry>(); |
| for (FocusEntry entry : mFocusHolders.values()) { |
| Log.d(TAG, "Evaluating focus holder: " + entry.getClientId()); |
| |
| // If this request is for Notifications and a current focus holder has specified |
| // AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE, then reject the request. |
| // This matches the hardwired behavior in the default audio policy engine which apps |
| // might expect (The interaction matrix doesn't have any provision for dealing with |
| // override flags like this). |
| if ((requestedContext == ContextNumber.NOTIFICATION) && |
| (entry.mAfi.getGainRequest() == |
| AudioManager.AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE)) { |
| return AudioManager.AUDIOFOCUS_REQUEST_FAILED; |
| } |
| |
| // We don't allow sharing listeners (client IDs) between two concurrent requests |
| // (because the app would have no way to know to which request a later event applied) |
| if (afi.getClientId().equals(entry.mAfi.getClientId())) { |
| if (entry.mAudioContext == requestedContext) { |
| // This is a request from a current focus holder. |
| // Abandon the previous request (without sending a LOSS notification to it), |
| // and don't check the interaction matrix for it. |
| Log.i(TAG, "Replacing accepted request from same client"); |
| replacedCurrentEntry = entry; |
| continue; |
| } else { |
| // Trivially reject a request for a different USAGE |
| Log.e(TAG, "Client " + entry.getClientId() + " has already requested focus " |
| + "for " + entry.mAfi.getAttributes().usageToString() + " - cannot " |
| + "request focus for " + afi.getAttributes().usageToString() + " on " |
| + "same listener."); |
| return AudioManager.AUDIOFOCUS_REQUEST_FAILED; |
| } |
| } |
| |
| // Check the interaction matrix for the relationship between this entry and the request |
| switch (sInteractionMatrix[entry.mAudioContext][requestedContext]) { |
| case INTERACTION_REJECT: |
| // This request is rejected, so nothing further to do |
| return AudioManager.AUDIOFOCUS_REQUEST_FAILED; |
| case INTERACTION_EXCLUSIVE: |
| // The new request will cause this existing entry to lose focus |
| losers.add(entry); |
| break; |
| case INTERACTION_CONCURRENT: |
| // If ducking isn't allowed by the focus requestor, then everybody else |
| // must get a LOSS. |
| // If a focus holder has set the AUDIOFOCUS_FLAG_PAUSES_ON_DUCKABLE_LOSS flag, |
| // they must get a LOSS message even if ducking would otherwise be allowed. |
| // If a focus holder holds the RECEIVE_CAR_AUDIO_DUCKING_EVENTS permission, |
| // they must receive all audio focus losses. |
| if (!allowDucking |
| || entry.wantsPauseInsteadOfDucking() |
| || entry.receivesDuckEvents()) { |
| losers.add(entry); |
| } |
| break; |
| default: |
| Log.e(TAG, "Bad interaction matrix value - rejecting"); |
| return AudioManager.AUDIOFOCUS_REQUEST_FAILED; |
| } |
| } |
| Log.i(TAG, "Scanning those who've already lost focus..."); |
| final ArrayList<FocusEntry> blocked = new ArrayList<FocusEntry>(); |
| for (FocusEntry entry : mFocusLosers.values()) { |
| Log.i(TAG, entry.mAfi.getClientId()); |
| |
| // If this request is for Notifications and a pending focus holder has specified |
| // AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE, then reject the request |
| if ((requestedContext == ContextNumber.NOTIFICATION) && |
| (entry.mAfi.getGainRequest() == |
| AudioManager.AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE)) { |
| return AudioManager.AUDIOFOCUS_REQUEST_FAILED; |
| } |
| |
| // We don't allow sharing listeners (client IDs) between two concurrent requests |
| // (because the app would have no way to know to which request a later event applied) |
| if (afi.getClientId().equals(entry.mAfi.getClientId())) { |
| if (entry.mAudioContext == requestedContext) { |
| // This is a repeat of a request that is currently blocked. |
| // Evaluate it as if it were a new request, but note that we should remove |
| // the old pending request, and move it. |
| // We do not want to evaluate the new request against itself. |
| Log.i(TAG, "Replacing pending request from same client"); |
| replacedBlockedEntry = entry; |
| continue; |
| } else { |
| // Trivially reject a request for a different USAGE |
| Log.e(TAG, "Client " + entry.getClientId() + " has already requested focus " |
| + "for " + entry.mAfi.getAttributes().usageToString() + " - cannot " |
| + "request focus for " + afi.getAttributes().usageToString() + " on " |
| + "same listener."); |
| return AudioManager.AUDIOFOCUS_REQUEST_FAILED; |
| } |
| } |
| |
| // Check the interaction matrix for the relationship between this entry and the request |
| switch (sInteractionMatrix[entry.mAudioContext][requestedContext]) { |
| case INTERACTION_REJECT: |
| // Even though this entry has currently lost focus, the fact that it is |
| // waiting to play means we'll reject this new conflicting request. |
| return AudioManager.AUDIOFOCUS_REQUEST_FAILED; |
| case INTERACTION_EXCLUSIVE: |
| // The new request is yet another reason this entry cannot regain focus (yet) |
| blocked.add(entry); |
| break; |
| case INTERACTION_CONCURRENT: |
| // If ducking is not allowed by the requester, or the pending focus holder had |
| // set the AUDIOFOCUS_FLAG_PAUSES_ON_DUCKABLE_LOSS flag, or if the pending |
| // focus holder has requested to receive all focus events, then the pending |
| // holder must stay "lost" until this requester goes away. |
| if (!allowDucking |
| || entry.wantsPauseInsteadOfDucking() |
| || entry.receivesDuckEvents()) { |
| // The new request is yet another reason this entry cannot regain focus yet |
| blocked.add(entry); |
| } |
| break; |
| default: |
| Log.e(TAG, "Bad interaction matrix value - rejecting"); |
| return AudioManager.AUDIOFOCUS_REQUEST_FAILED; |
| } |
| } |
| |
| |
| // Now that we've decided we'll grant focus, construct our new FocusEntry |
| FocusEntry newEntry = new FocusEntry(afi, requestedContext); |
| |
| // These entries have permanently lost focus as a result of this request, so they |
| // should be removed from all blocker lists. |
| ArrayList<FocusEntry> permanentlyLost = new ArrayList<>(); |
| |
| if (replacedCurrentEntry != null) { |
| mFocusHolders.remove(replacedCurrentEntry.getClientId()); |
| permanentlyLost.add(replacedCurrentEntry); |
| } |
| if (replacedBlockedEntry != null) { |
| mFocusLosers.remove(replacedBlockedEntry.getClientId()); |
| permanentlyLost.add(replacedBlockedEntry); |
| } |
| |
| |
| // Now that we're sure we'll accept this request, update any requests which we would |
| // block but are already out of focus but waiting to come back |
| for (FocusEntry entry : blocked) { |
| // If we're out of focus it must be because somebody is blocking us |
| assert !entry.mBlockers.isEmpty(); |
| |
| if (permanent) { |
| // This entry has now lost focus forever |
| sendFocusLoss(entry, AudioManager.AUDIOFOCUS_LOSS); |
| entry.mReceivedLossTransientCanDuck = false; |
| final FocusEntry deadEntry = mFocusLosers.remove(entry.mAfi.getClientId()); |
| assert deadEntry != null; |
| permanentlyLost.add(entry); |
| } else { |
| if (!allowDucking && entry.mReceivedLossTransientCanDuck) { |
| // This entry was previously allowed to duck, but can no longer do so. |
| Log.i(TAG, "Converting duckable loss to non-duckable for " |
| + entry.getClientId()); |
| sendFocusLoss(entry, AudioManager.AUDIOFOCUS_LOSS_TRANSIENT); |
| entry.mReceivedLossTransientCanDuck = false; |
| } |
| // Note that this new request is yet one more reason we can't (yet) have focus |
| entry.mBlockers.add(newEntry); |
| } |
| } |
| |
| // Notify and update any requests which are now losing focus as a result of the new request |
| for (FocusEntry entry : losers) { |
| // If we have focus (but are about to loose it), nobody should be blocking us yet |
| assert entry.mBlockers.isEmpty(); |
| |
| int lossType; |
| if (permanent) { |
| lossType = AudioManager.AUDIOFOCUS_LOSS; |
| } else if (allowDucking && entry.receivesDuckEvents()) { |
| lossType = AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK; |
| entry.mReceivedLossTransientCanDuck = true; |
| } else { |
| lossType = AudioManager.AUDIOFOCUS_LOSS_TRANSIENT; |
| } |
| sendFocusLoss(entry, lossType); |
| |
| // The entry no longer holds focus, so take it out of the holders list |
| mFocusHolders.remove(entry.mAfi.getClientId()); |
| |
| if (permanent) { |
| permanentlyLost.add(entry); |
| } else { |
| // Add ourselves to the list of requests waiting to get focus back and |
| // note why we lost focus so we can tell when it's time to get it back |
| mFocusLosers.put(entry.mAfi.getClientId(), entry); |
| entry.mBlockers.add(newEntry); |
| } |
| } |
| |
| // Now that all new blockers have been added, clear out any other requests that have been |
| // permanently lost as a result of this request. Treat them as abandoned - if they're on |
| // any blocker lists, remove them. If any focus requests become unblocked as a result, |
| // re-grant them. (This can happen when a GAIN_TRANSIENT_MAY_DUCK request replaces a |
| // GAIN_TRANSIENT request from the same listener.) |
| for (FocusEntry entry : permanentlyLost) { |
| Log.d(TAG, "Cleaning up entry " + entry.getClientId()); |
| removeFocusEntryAndRestoreUnblockedWaiters(entry); |
| } |
| |
| // Finally, add the request we're granting to the focus holders' list |
| mFocusHolders.put(afi.getClientId(), newEntry); |
| |
| Log.i(TAG, "AUDIOFOCUS_REQUEST_GRANTED"); |
| return AudioManager.AUDIOFOCUS_REQUEST_GRANTED; |
| } |
| |
| |
| @Override |
| public synchronized void onAudioFocusRequest(AudioFocusInfo afi, int requestResult) { |
| Log.i(TAG, "onAudioFocusRequest " + afi.getClientId()); |
| |
| int response = evaluateFocusRequest(afi); |
| |
| // Post our reply for delivery to the original focus requester |
| mAudioManager.setFocusRequestResult(afi, response, mAudioPolicy); |
| } |
| |
| |
| /** |
| * @see AudioManager#abandonAudioFocus(AudioManager.OnAudioFocusChangeListener, AudioAttributes) |
| * Note that we'll get this call for a focus holder that dies while in the focus stack, so |
| * we don't need to watch for death notifications directly. |
| * */ |
| @Override |
| public synchronized void onAudioFocusAbandon(AudioFocusInfo afi) { |
| Log.i(TAG, "onAudioFocusAbandon " + afi.getClientId()); |
| |
| // Remove this entry from our active or pending list |
| FocusEntry deadEntry = mFocusHolders.remove(afi.getClientId()); |
| if (deadEntry == null) { |
| deadEntry = mFocusLosers.remove(afi.getClientId()); |
| if (deadEntry == null) { |
| // Caller is providing an unrecognzied clientId!? |
| Log.w(TAG, "Audio focus abandoned by unrecognized client id: " + afi.getClientId()); |
| // This probably means an app double released focused for some reason. One |
| // harmless possibility is a race between an app being told it lost focus and the |
| // app voluntarily abandoning focus. More likely the app is just sloppy. :) |
| // The more nefarious possibility is that the clientId is actually corrupted |
| // somehow, in which case we might have a real focus entry that we're going to fail |
| // to remove. If that were to happen, I'd expect either the app to swallow it |
| // silently, or else take unexpected action (eg: resume playing spontaneously), or |
| // else to see "Failure to signal ..." gain/loss error messages in the log from |
| // this module when a focus change tries to take action on a truly zombie entry. |
| return; |
| } |
| } |
| |
| removeFocusEntryAndRestoreUnblockedWaiters(deadEntry); |
| } |
| |
| private void removeFocusEntryAndRestoreUnblockedWaiters(FocusEntry deadEntry) { |
| // Remove this entry from the blocking list of any pending requests |
| Iterator<FocusEntry> it = mFocusLosers.values().iterator(); |
| while (it.hasNext()) { |
| FocusEntry entry = it.next(); |
| |
| // Remove the retiring entry from all blocker lists |
| entry.mBlockers.remove(deadEntry); |
| |
| // Any entry whose blocking list becomes empty should regain focus |
| if (entry.mBlockers.isEmpty()) { |
| Log.i(TAG, "Restoring unblocked entry " + entry.getClientId()); |
| // Pull this entry out of the focus losers list |
| it.remove(); |
| |
| // Add it back into the focus holders list |
| mFocusHolders.put(entry.getClientId(), entry); |
| |
| // Send the focus (re)gain notification |
| int result = mAudioManager.dispatchAudioFocusChange( |
| entry.mAfi, |
| entry.mAfi.getGainRequest(), |
| mAudioPolicy); |
| if (result != AudioManager.AUDIOFOCUS_REQUEST_GRANTED) { |
| // TODO: Is this actually an error, or is it okay for an entry in the focus |
| // stack to NOT have a listener? If that's the case, should we even keep |
| // it in the focus stack? |
| Log.e(TAG, "Failure to signal gain of audio focus with error: " + result); |
| } |
| } |
| } |
| } |
| |
| public synchronized void dump(PrintWriter writer) { |
| writer.println("*CarAudioFocus*"); |
| |
| writer.println(" Current Focus Holders:"); |
| for (String clientId : mFocusHolders.keySet()) { |
| System.out.println(clientId); |
| } |
| |
| writer.println(" Transient Focus Losers:"); |
| for (String clientId : mFocusLosers.keySet()) { |
| System.out.println(clientId); |
| } |
| } |
| |
| private static String focusEventToString(int focusEvent) { |
| switch (focusEvent) { |
| case AudioManager.AUDIOFOCUS_GAIN: |
| return "GAIN"; |
| case AudioManager.AUDIOFOCUS_GAIN_TRANSIENT: |
| return "GAIN_TRANSIENT"; |
| case AudioManager.AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE: |
| return "GAIN_TRANSIENT_EXCLUSIVE"; |
| case AudioManager.AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK: |
| return "GAIN_TRANSIENT_MAY_DUCK"; |
| case AudioManager.AUDIOFOCUS_LOSS: |
| return "LOSS"; |
| case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT: |
| return "LOSS_TRANSIENT"; |
| case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK: |
| return "LOSS_TRANSIENT_CAN_DUCK"; |
| default: |
| return "unknown event " + focusEvent; |
| } |
| } |
| } |