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      1 /*
      2  * Copyright (C) 2012 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.mms.util;
     18 
     19 import java.util.Set;
     20 
     21 import android.content.Context;
     22 import android.net.Uri;
     23 import android.util.Log;
     24 
     25 import com.android.mms.LogTag;
     26 import com.android.mms.model.SlideshowModel;
     27 import com.google.android.mms.MmsException;
     28 import com.google.android.mms.pdu.GenericPdu;
     29 import com.google.android.mms.pdu.MultimediaMessagePdu;
     30 import com.google.android.mms.pdu.PduPersister;
     31 import com.google.android.mms.util.PduCache;
     32 import com.google.android.mms.util.PduCacheEntry;
     33 
     34 /**
     35  * Primary {@link PduLoaderManager} implementation used by {@link MessagingApplication}.
     36  * <p>
     37  * Public methods should only be used from a single thread (typically the UI
     38  * thread). Callbacks will be invoked on the thread where the PduLoaderManager
     39  * was instantiated.
     40  * <p>
     41  * Uses a thread-pool ExecutorService instead of AsyncTasks since clients may
     42  * request lots of pdus around the same time, and AsyncTask may reject tasks
     43  * in that case and has no way of bounding the number of threads used by those
     44  * tasks.
     45  * <p>
     46  * PduLoaderManager is used to asynchronously load mms pdu's and then build a slideshow model
     47  * from that loaded pdu. Then it will call the passed in callback with the result. This class
     48  * uses the PduCache built into the mms framework. It also manages a local cache of slideshow
     49  * models. The slideshow cache uses SoftReferences to hang onto the slideshow.
     50  *
     51  * Based on BooksImageManager by Virgil King.
     52  */
     53 public class PduLoaderManager extends BackgroundLoaderManager {
     54     private static final String TAG = LogTag.TAG;
     55 
     56     private static final boolean DEBUG_DISABLE_CACHE = false;
     57     private static final boolean DEBUG_DISABLE_PDUS = false;
     58     private static final boolean DEBUG_LONG_WAIT = false;
     59 
     60     private static PduCache mPduCache;
     61     private final PduPersister mPduPersister;
     62     private final SimpleCache<Uri, SlideshowModel> mSlideshowCache;
     63     private final Context mContext;
     64 
     65     public PduLoaderManager(final Context context) {
     66         super(context);
     67 
     68         mSlideshowCache = new SimpleCache<Uri, SlideshowModel>(8, 16, 0.75f, false);
     69         mPduCache = PduCache.getInstance();
     70         mPduPersister = PduPersister.getPduPersister(context);
     71         mContext = context;
     72     }
     73 
     74     public ItemLoadedFuture getPdu(Uri uri, boolean requestSlideshow,
     75             final ItemLoadedCallback<PduLoaded> callback) {
     76         if (uri == null) {
     77             throw new NullPointerException();
     78         }
     79 
     80         PduCacheEntry cacheEntry = null;
     81         synchronized(mPduCache) {
     82             if (!mPduCache.isUpdating(uri)) {
     83                 cacheEntry = mPduCache.get(uri);
     84             }
     85         }
     86         final SlideshowModel slideshow = (requestSlideshow && !DEBUG_DISABLE_CACHE) ?
     87                 mSlideshowCache.get(uri) : null;
     88 
     89         final boolean slideshowExists = (!requestSlideshow || slideshow != null);
     90         final boolean pduExists = (cacheEntry != null && cacheEntry.getPdu() != null);
     91         final boolean taskExists = mPendingTaskUris.contains(uri);
     92         final boolean newTaskRequired = (!pduExists || !slideshowExists) && !taskExists;
     93         final boolean callbackRequired = (callback != null);
     94 
     95         if (pduExists && slideshowExists) {
     96             if (callbackRequired) {
     97                 PduLoaded pduLoaded = new PduLoaded(cacheEntry.getPdu(), slideshow);
     98                 callback.onItemLoaded(pduLoaded, null);
     99             }
    100             return new NullItemLoadedFuture();
    101         }
    102 
    103         if (callbackRequired) {
    104             addCallback(uri, callback);
    105         }
    106 
    107         if (newTaskRequired) {
    108             mPendingTaskUris.add(uri);
    109             Runnable task = new PduTask(uri, requestSlideshow);
    110             mExecutor.execute(task);
    111         }
    112         return new ItemLoadedFuture() {
    113             private boolean mIsDone;
    114 
    115             public void cancel(Uri uri) {
    116                 cancelCallback(callback);
    117                 removePdu(uri);     // the pdu and/or slideshow might be half loaded. Make sure
    118                                     // we load fresh the next time this uri is requested.
    119             }
    120 
    121             public void setIsDone(boolean done) {
    122                 mIsDone = done;
    123             }
    124 
    125             public boolean isDone() {
    126                 return mIsDone;
    127             }
    128         };
    129     }
    130 
    131     @Override
    132     public void clear() {
    133         super.clear();
    134 
    135         synchronized(mPduCache) {
    136             mPduCache.purgeAll();
    137         }
    138         mSlideshowCache.clear();
    139     }
    140 
    141     public void removePdu(Uri uri) {
    142         if (Log.isLoggable(TAG, Log.DEBUG)) {
    143             Log.d(TAG, "removePdu: " + uri);
    144         }
    145         if (uri != null) {
    146             synchronized(mPduCache) {
    147                 mPduCache.purge(uri);
    148             }
    149             mSlideshowCache.remove(uri);
    150         }
    151     }
    152 
    153     public String getTag() {
    154         return TAG;
    155     }
    156 
    157     public class PduTask implements Runnable {
    158         private final Uri mUri;
    159         private final boolean mRequestSlideshow;
    160 
    161         public PduTask(Uri uri, boolean requestSlideshow) {
    162             if (uri == null) {
    163                 throw new NullPointerException();
    164             }
    165             mUri = uri;
    166             mRequestSlideshow = requestSlideshow;
    167         }
    168 
    169         /** {@inheritDoc} */
    170         public void run() {
    171             if (DEBUG_DISABLE_PDUS) {
    172                 return;
    173             }
    174             if (DEBUG_LONG_WAIT) {
    175                 try {
    176                     Thread.sleep(10000);
    177                 } catch (InterruptedException e) {
    178                 }
    179             }
    180             GenericPdu pdu = null;
    181             SlideshowModel slideshow = null;
    182             Throwable exception = null;
    183             try {
    184                 pdu = mPduPersister.load(mUri);
    185                 if (pdu != null && mRequestSlideshow) {
    186                     slideshow = SlideshowModel.createFromPduBody(mContext,
    187                             ((MultimediaMessagePdu)pdu).getBody());
    188                 }
    189             } catch (final MmsException e) {
    190                 Log.e(TAG, "MmsException loading uri: " + mUri, e);
    191                 exception = e;
    192             }
    193             final GenericPdu resultPdu = pdu;
    194             final SlideshowModel resultSlideshow = slideshow;
    195             final Throwable resultException = exception;
    196             mCallbackHandler.post(new Runnable() {
    197                 public void run() {
    198                     final Set<ItemLoadedCallback> callbacks = mCallbacks.get(mUri);
    199                     if (callbacks != null) {
    200                         // Make a copy so that the callback can unregister itself
    201                         for (final ItemLoadedCallback<PduLoaded> callback : asList(callbacks)) {
    202                             if (Log.isLoggable(TAG, Log.DEBUG)) {
    203                                 Log.d(TAG, "Invoking pdu callback " + callback);
    204                             }
    205                             PduLoaded pduLoaded = new PduLoaded(resultPdu, resultSlideshow);
    206                             callback.onItemLoaded(pduLoaded, resultException);
    207                         }
    208                     }
    209                     // Add the slideshow to the soft cache if the load succeeded
    210                     if (resultSlideshow != null) {
    211                         mSlideshowCache.put(mUri, resultSlideshow);
    212                     }
    213 
    214                     mCallbacks.remove(mUri);
    215                     mPendingTaskUris.remove(mUri);
    216 
    217                     if (Log.isLoggable(LogTag.PDU_CACHE, Log.DEBUG)) {
    218                         Log.d(TAG, "Pdu task for " + mUri + "exiting; " + mPendingTaskUris.size()
    219                                 + " remain");
    220                     }
    221                 }
    222             });
    223         }
    224     }
    225 
    226     public static class PduLoaded {
    227         public final GenericPdu mPdu;
    228         public final SlideshowModel mSlideshow;
    229 
    230         public PduLoaded(GenericPdu pdu, SlideshowModel slideshow) {
    231             mPdu = pdu;
    232             mSlideshow = slideshow;
    233         }
    234     }
    235 }
    236