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/*
* Copyright (C) 2012 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.mms.util;
import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import android.content.Context;
import android.content.SharedPreferences;
import android.preference.PreferenceManager;
import android.util.Log;
import com.android.mms.LogTag;
public class CacheManager {
private static final String TAG = LogTag.TAG;
private static final String KEY_CACHE_UP_TO_DATE = "cache-up-to-date";
private static HashMap<String, BlobCache> sCacheMap =
new HashMap<String, BlobCache>();
private static boolean sOldCheckDone = false;
private static final boolean PUT_CACHE_ON_SDCARD = false;
// Return null when we cannot instantiate a BlobCache, e.g.:
// there is no SD card found.
// This can only be called from data thread.
public static BlobCache getCache(Context context, String filename,
int maxEntries, int maxBytes, int version) {
synchronized (sCacheMap) {
if (!sOldCheckDone) {
removeOldFilesIfNecessary(context);
sOldCheckDone = true;
}
BlobCache cache = sCacheMap.get(filename);
if (cache == null) {
File cacheDir = PUT_CACHE_ON_SDCARD ? context.getExternalCacheDir()
: context.getCacheDir();
String path = cacheDir.getAbsolutePath() + "/" + filename;
Log.d(TAG, "Cache dir: " + path);
try {
cache = new BlobCache(path, maxEntries, maxBytes, false,
version);
sCacheMap.put(filename, cache);
} catch (IOException e) {
Log.e(TAG, "Cannot instantiate cache!", e);
}
}
return cache;
}
}
// Removes the old files if the data is wiped.
private static void removeOldFilesIfNecessary(Context context) {
SharedPreferences pref = PreferenceManager
.getDefaultSharedPreferences(context);
int n = 0;
try {
n = pref.getInt(KEY_CACHE_UP_TO_DATE, 0);
} catch (Throwable t) {
// ignore.
}
if (n != 0) return;
pref.edit().putInt(KEY_CACHE_UP_TO_DATE, 1).commit();
clear(context);
}
public static void clear(Context context) {
File cacheDir = PUT_CACHE_ON_SDCARD ? context.getExternalCacheDir()
: context.getCacheDir();
String prefix = cacheDir.getAbsolutePath() + "/";
BlobCache.deleteFiles(prefix + ImageCacheService.IMAGE_CACHE_FILE);
sCacheMap.remove(ImageCacheService.IMAGE_CACHE_FILE);
}
}
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