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.io.File; 20 import java.io.IOException; 21 import java.util.HashMap; 22 23 import android.content.Context; 24 import android.content.SharedPreferences; 25 import android.preference.PreferenceManager; 26 import android.util.Log; 27 28 public class CacheManager { 29 private static final String TAG = "CacheManager"; 30 private static final String KEY_CACHE_UP_TO_DATE = "cache-up-to-date"; 31 private static HashMap<String, BlobCache> sCacheMap = 32 new HashMap<String, BlobCache>(); 33 private static boolean sOldCheckDone = false; 34 35 private static final boolean PUT_CACHE_ON_SDCARD = false; 36 37 // Return null when we cannot instantiate a BlobCache, e.g.: 38 // there is no SD card found. 39 // This can only be called from data thread. getCache(Context context, String filename, int maxEntries, int maxBytes, int version)40 public static BlobCache getCache(Context context, String filename, 41 int maxEntries, int maxBytes, int version) { 42 synchronized (sCacheMap) { 43 if (!sOldCheckDone) { 44 removeOldFilesIfNecessary(context); 45 sOldCheckDone = true; 46 } 47 BlobCache cache = sCacheMap.get(filename); 48 if (cache == null) { 49 File cacheDir = PUT_CACHE_ON_SDCARD ? context.getExternalCacheDir() 50 : context.getCacheDir(); 51 String path = cacheDir.getAbsolutePath() + "/" + filename; 52 Log.d(TAG, "Cache dir: " + path); 53 try { 54 cache = new BlobCache(path, maxEntries, maxBytes, false, 55 version); 56 sCacheMap.put(filename, cache); 57 } catch (IOException e) { 58 Log.e(TAG, "Cannot instantiate cache!", e); 59 } 60 } 61 return cache; 62 } 63 } 64 65 // Removes the old files if the data is wiped. removeOldFilesIfNecessary(Context context)66 private static void removeOldFilesIfNecessary(Context context) { 67 SharedPreferences pref = PreferenceManager 68 .getDefaultSharedPreferences(context); 69 int n = 0; 70 try { 71 n = pref.getInt(KEY_CACHE_UP_TO_DATE, 0); 72 } catch (Throwable t) { 73 // ignore. 74 } 75 if (n != 0) return; 76 pref.edit().putInt(KEY_CACHE_UP_TO_DATE, 1).commit(); 77 78 clear(context); 79 } 80 clear(Context context)81 public static void clear(Context context) { 82 File cacheDir = PUT_CACHE_ON_SDCARD ? context.getExternalCacheDir() 83 : context.getCacheDir(); 84 String prefix = cacheDir.getAbsolutePath() + "/"; 85 86 BlobCache.deleteFiles(prefix + ImageCacheService.IMAGE_CACHE_FILE); 87 sCacheMap.remove(ImageCacheService.IMAGE_CACHE_FILE); 88 } 89 } 90