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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 = "Mms:PduLoaderManager";
     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, true);
     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             public void cancel() {
    114                 cancelCallback(callback);
    115             }
    116             public boolean isDone() {
    117                 return false;
    118             }
    119         };
    120     }
    121 
    122     @Override
    123     public void clear() {
    124         super.clear();
    125 
    126         synchronized(mPduCache) {
    127             mPduCache.purgeAll();
    128         }
    129         mSlideshowCache.clear();
    130     }
    131 
    132     public void removePdu(Uri uri) {
    133         if (Log.isLoggable(TAG, Log.DEBUG)) {
    134             Log.d(TAG, "removePdu: " + uri);
    135         }
    136         synchronized(mPduCache) {
    137             mPduCache.purge(uri);
    138         }
    139         mSlideshowCache.remove(uri);
    140     }
    141 
    142     public String getTag() {
    143         return TAG;
    144     }
    145 
    146     public class PduTask implements Runnable {
    147         private final Uri mUri;
    148         private final boolean mRequestSlideshow;
    149 
    150         public PduTask(Uri uri, boolean requestSlideshow) {
    151             if (uri == null) {
    152                 throw new NullPointerException();
    153             }
    154             mUri = uri;
    155             mRequestSlideshow = requestSlideshow;
    156         }
    157 
    158         /** {@inheritDoc} */
    159         public void run() {
    160             if (DEBUG_DISABLE_PDUS) {
    161                 return;
    162             }
    163             if (DEBUG_LONG_WAIT) {
    164                 try {
    165                     Thread.sleep(10000);
    166                 } catch (InterruptedException e) {
    167                 }
    168             }
    169             GenericPdu pdu = null;
    170             SlideshowModel slideshow = null;
    171             Throwable exception = null;
    172             try {
    173                 pdu = mPduPersister.load(mUri);
    174                 if (pdu != null && mRequestSlideshow) {
    175                     slideshow = SlideshowModel.createFromPduBody(mContext,
    176                             ((MultimediaMessagePdu)pdu).getBody());
    177                 }
    178             } catch (final MmsException e) {
    179                 Log.e(TAG, "MmsException loading uri: " + mUri, e);
    180                 exception = e;
    181             }
    182             final GenericPdu resultPdu = pdu;
    183             final SlideshowModel resultSlideshow = slideshow;
    184             final Throwable resultException = exception;
    185             mCallbackHandler.post(new Runnable() {
    186                 public void run() {
    187                     final Set<ItemLoadedCallback> callbacks = mCallbacks.get(mUri);
    188                     if (callbacks != null) {
    189                         // Make a copy so that the callback can unregister itself
    190                         for (final ItemLoadedCallback<PduLoaded> callback : asList(callbacks)) {
    191                             if (Log.isLoggable(TAG, Log.DEBUG)) {
    192                                 Log.d(TAG, "Invoking pdu callback " + callback);
    193                             }
    194                             PduLoaded pduLoaded = new PduLoaded(resultPdu, resultSlideshow);
    195                             callback.onItemLoaded(pduLoaded, resultException);
    196                         }
    197                     }
    198                     // Add the slideshow to the soft cache if the load succeeded
    199                     if (resultSlideshow != null) {
    200                         mSlideshowCache.put(mUri, resultSlideshow);
    201                     }
    202 
    203                     mCallbacks.remove(mUri);
    204                     mPendingTaskUris.remove(mUri);
    205 
    206                     if (Log.isLoggable(LogTag.PDU_CACHE, Log.DEBUG)) {
    207                         Log.d(TAG, "Pdu task for " + mUri + "exiting; " + mPendingTaskUris.size()
    208                                 + " remain");
    209                     }
    210                 }
    211             });
    212         }
    213     }
    214 
    215     public static class PduLoaded {
    216         public final GenericPdu mPdu;
    217         public final SlideshowModel mSlideshow;
    218 
    219         public PduLoaded(GenericPdu pdu, SlideshowModel slideshow) {
    220             mPdu = pdu;
    221             mSlideshow = slideshow;
    222         }
    223     }
    224 }
    225