diff --git a/java/src/com/android/inputmethod/dictionarypack/DictionaryService.java b/java/src/com/android/inputmethod/dictionarypack/DictionaryService.java index 767f895dc..939c25f10 100644 --- a/java/src/com/android/inputmethod/dictionarypack/DictionaryService.java +++ b/java/src/com/android/inputmethod/dictionarypack/DictionaryService.java @@ -22,13 +22,14 @@ import android.app.Service; import android.content.Context; import android.content.Intent; import android.os.IBinder; -import android.util.Log; import android.widget.Toast; import com.android.inputmethod.latin.R; import java.util.Locale; import java.util.Random; +import java.util.concurrent.LinkedBlockingQueue; +import java.util.concurrent.ThreadPoolExecutor; import java.util.concurrent.TimeUnit; /** @@ -92,21 +93,27 @@ public final class DictionaryService extends Service { private static final long VERY_LONG_TIME = TimeUnit.DAYS.toMillis(14); /** - * The last seen start Id. This must be stored because we must only call stopSelfResult() with - * the last seen Id, or the service won't stop. + * An executor that serializes tasks given to it. */ - private int mLastSeenStartId; - - /** - * The command count. We need this because we need to not call stopSelfResult() while we still - * have commands running. - */ - private int mCommandCount; + private ThreadPoolExecutor mExecutor; + private static final int WORKER_THREAD_TIMEOUT_SECONDS = 15; @Override public void onCreate() { - mLastSeenStartId = 0; - mCommandCount = 0; + // By default, a thread pool executor does not timeout its core threads, so it will + // never kill them when there isn't any work to do any more. That would mean the service + // can never die! By creating it this way and calling allowCoreThreadTimeOut, we allow + // the single thread to time out after WORKER_THREAD_TIMEOUT_SECONDS = 15 seconds, allowing + // the process to be reclaimed by the system any time after that if it's not doing + // anything else. + // Executors#newSingleThreadExecutor creates a ThreadPoolExecutor but it returns the + // superclass ExecutorService which does not have the #allowCoreThreadTimeOut method, + // so we can't use that. + mExecutor = new ThreadPoolExecutor(1 /* corePoolSize */, 1 /* maximumPoolSize */, + WORKER_THREAD_TIMEOUT_SECONDS /* keepAliveTime */, + TimeUnit.SECONDS /* unit for keepAliveTime */, + new LinkedBlockingQueue() /* workQueue */); + mExecutor.allowCoreThreadTimeOut(true); } @Override @@ -131,33 +138,35 @@ public final class DictionaryService extends Service { * - Handle a finished download. * This executes the actions that must be taken after a file (metadata or dictionary data * has been downloaded (or failed to download). + * The commands that can be spun an another thread will be executed serially, in order, on + * a worker thread that is created on demand and terminates after a short while if there isn't + * any work left to do. */ @Override public synchronized int onStartCommand(final Intent intent, final int flags, final int startId) { final DictionaryService self = this; - mLastSeenStartId = startId; - mCommandCount += 1; if (SHOW_DOWNLOAD_TOAST_INTENT_ACTION.equals(intent.getAction())) { // This is a UI action, it can't be run in another thread showStartDownloadingToast(this, LocaleUtils.constructLocaleFromString( intent.getStringExtra(LOCALE_INTENT_ARGUMENT))); } else { - // If it's a command that does not require UI, create a thread to do the work - // and return right away. DATE_CHANGED or UPDATE_NOW are examples of such commands. - new Thread("updateOrFinishDownload") { + // If it's a command that does not require UI, arrange for the work to be done on a + // separate thread, so that we can return right away. The executor will spawn a thread + // if necessary, or reuse a thread that has become idle as appropriate. + // DATE_CHANGED or UPDATE_NOW are examples of commands that can be done on another + // thread. + mExecutor.submit(new Runnable() { @Override public void run() { dispatchBroadcast(self, intent); - synchronized(self) { - if (--mCommandCount <= 0) { - if (!stopSelfResult(mLastSeenStartId)) { - Log.e(TAG, "Can't stop ourselves"); - } - } - } + // Since calls to onStartCommand are serialized, the submissions to the executor + // are serialized. That means we are guaranteed to call the stopSelfResult() + // in the same order that we got them, so we don't need to take care of the + // order. + stopSelfResult(startId); } - }.start(); + }); } return Service.START_REDELIVER_INTENT; }