/*
* 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.ccxt.whl.video.util;
import java.io.File;
import java.lang.ref.SoftReference;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import android.annotation.TargetApi;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.graphics.drawable.BitmapDrawable;
import android.os.Build.VERSION_CODES;
import android.os.Bundle;
import android.os.Environment;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.util.LruCache;
import android.util.Log;
import com.ccxt.whl.BuildConfig;
/**
* This class memory caching of bitmaps in conjunction with the
* {@link ImageWorker} class and its subclasses. Use
* {@link ImageCache#getInstance(android.support.v4.app.FragmentManager, ImageCacheParams)}
* to get an instance of this class, although usually a cache should be added
* directly to an {@link ImageWorker} by calling
* {@link ImageWorker#addImageCache(android.support.v4.app.FragmentManager, ImageCacheParams)}
* .
*/
public class ImageCache {
private static final String TAG = "ImageCache";
// Default memory cache size in kilobytes
private static final int DEFAULT_MEM_CACHE_SIZE = 1024 * 5; // 5MB
private static final int DEFAULT_COMPRESS_QUALITY = 70;
// Constants to easily toggle various caches
private static final boolean DEFAULT_MEM_CACHE_ENABLED = true;
private static final boolean DEFAULT_INIT_DISK_CACHE_ON_CREATE = false;
private LruCache<String, BitmapDrawable> mMemoryCache;
private ImageCacheParams mCacheParams;
private Set<SoftReference<Bitmap>> mReusableBitmaps;
/**
* Create a new ImageCache object using the specified parameters. This
* should not be called directly by other classes, instead use
* {@link ImageCache#getInstance(android.support.v4.app.FragmentManager, ImageCacheParams)}
* to fetch an ImageCache instance.
*
* @param cacheParams
* The cache parameters to use to initialize the cache
*/
private ImageCache(ImageCacheParams cacheParams) {
init(cacheParams);
}
/**
* Return an {@link ImageCache} instance. A {@link RetainFragment} is used
* to retain the ImageCache object across configuration changes such as a
* change in device orientation.
*
* @param fragmentManager
* The fragment manager to use when dealing with the retained
* fragment.
* @param cacheParams
* The cache parameters to use if the ImageCache needs
* instantiation.
* @return An existing retained ImageCache object or a new one if one did
* not exist
*/
public static ImageCache getInstance(FragmentManager fragmentManager,
ImageCacheParams cacheParams) {
// Search for, or create an instance of the non-UI RetainFragment
final RetainFragment mRetainFragment = findOrCreateRetainFragment(fragmentManager);
// See if we already have an ImageCache stored in RetainFragment
ImageCache imageCache = (ImageCache) mRetainFragment.getObject();
// No existing ImageCache, create one and store it in RetainFragment
if (imageCache == null) {
imageCache = new ImageCache(cacheParams);
mRetainFragment.setObject(imageCache);
}
return imageCache;
}
/**
* Initialize the cache, providing all parameters.
*
* @param cacheParams
* The cache parameters to initialize the cache
*/
private void init(ImageCacheParams cacheParams) {
mCacheParams = cacheParams;
// BEGIN_INCLUDE(init_memory_cache)
// Set up memory cache
if (mCacheParams.memoryCacheEnabled) {
if (BuildConfig.DEBUG) {
Log.d(TAG, "Memory cache created (size = "
+ mCacheParams.memCacheSize + ")");
}
// If we're running on Honeycomb or newer, create a set of reusable
// bitmaps that can be
// populated into the inBitmap field of BitmapFactory.Options. Note
// that the set is
// of SoftReferences which will actually not be very effective due
// to the garbage
// collector being aggressive clearing Soft/WeakReferences. A better
// approach
// would be to use a strongly references bitmaps, however this would
// require some
// balancing of memory usage between this set and the bitmap
// LruCache. It would also
// require knowledge of the expected size of the bitmaps. From
// Honeycomb to JellyBean
// the size would need to be precise, from KitKat onward the size
// would just need to
// be the upper bound (due to changes in how inBitmap can re-use
// bitmaps).
if (Utils.hasHoneycomb()) {
mReusableBitmaps = Collections
.synchronizedSet(new HashSet<SoftReference<Bitmap>>());
}
mMemoryCache = new LruCache<String, BitmapDrawable>(
mCacheParams.memCacheSize) {
/**
* Notify the removed entry that is no longer being cached
*/
@Override
protected void entryRemoved(boolean evicted, String key,
BitmapDrawable oldValue, BitmapDrawable newValue) {
if (RecyclingBitmapDrawable.class.isInstance(oldValue)) {
// The removed entry is a recycling drawable, so notify
// it
// that it has been removed from the memory cache
((RecyclingBitmapDrawable) oldValue).setIsCached(false);
} else {
// The removed entry is a standard BitmapDrawable
if (Utils.hasHoneycomb()) {
// We're running on Honeycomb or later, so add the
// bitmap
// to a SoftReference set for possible use with
// inBitmap later
mReusableBitmaps.add(new SoftReference<Bitmap>(
oldValue.getBitmap()));
}
}
}
/**
* Measure item size in kilobytes rather than units which is
* more practical for a bitmap cache
*/
@Override
protected int sizeOf(String key, BitmapDrawable value) {
final int bitmapSize = getBitmapSize(value) / 1024;
return bitmapSize == 0 ? 1 : bitmapSize;
}
};
}
}
/**
* Adds a bitmap to both memory and disk cache.
*
* @param data
* Unique identifier for the bitmap to store
* @param value
* The bitmap drawable to store
*/
public void addBitmapToCache(String data, BitmapDrawable value) {
// BEGIN_INCLUDE(add_bitmap_to_cache)
if (data == null || value == null) {
return;
}
// Add to memory cache
if (mMemoryCache != null) {
if (RecyclingBitmapDrawable.class.isInstance(value)) {
// The removed entry is a recycling drawable, so notify it
// that it has been added into the memory cache
((RecyclingBitmapDrawable) value).setIsCached(true);
}
mMemoryCache.put(data, value);
}
}
/**
* Get from memory cache.
*
* @param data
* Unique identifier for which item to get
* @return The bitmap drawable if found in cache, null otherwise
*/
public BitmapDrawable getBitmapFromMemCache(String data) {
// BEGIN_INCLUDE(get_bitmap_from_mem_cache)
BitmapDrawable memValue = null;
if (mMemoryCache != null) {
memValue = mMemoryCache.get(data);
}
if (BuildConfig.DEBUG && memValue != null) {
Log.d(TAG, "Memory cache hit");
}
return memValue;
// END_INCLUDE(get_bitmap_from_mem_cache)
}
/**
* @param options
* - BitmapFactory.Options with out* options populated
* @return Bitmap that case be used for inBitmap
*/
protected Bitmap getBitmapFromReusableSet(BitmapFactory.Options options) {
// BEGIN_INCLUDE(get_bitmap_from_reusable_set)
Bitmap bitmap = null;
if (mReusableBitmaps != null && !mReusableBitmaps.isEmpty()) {
synchronized (mReusableBitmaps) {
final Iterator<SoftReference<Bitmap>> iterator = mReusableBitmaps
.iterator();
Bitmap item;
while (iterator.hasNext()) {
item = iterator.next().get();
if (null != item && item.isMutable()) {
// Check to see it the item can be used for inBitmap
if (canUseForInBitmap(item, options)) {
bitmap = item;
// Remove from reusable set so it can't be used
// again
iterator.remove();
break;
}
} else {
// Remove from the set if the reference has been
// cleared.
iterator.remove();
}
}
}
}
return bitmap;
// END_INCLUDE(get_bitmap_from_reusable_set)
}
/**
* Clears both the memory and disk cache associated with this ImageCache
* object. Note that this includes disk access so this should not be
* executed on the main/UI thread.
*/
public void clearCache() {
if (mMemoryCache != null) {
mMemoryCache.evictAll();
if (BuildConfig.DEBUG) {
Log.d(TAG, "Memory cache cleared");
}
}
}
/**
* A holder class that contains cache parameters.
*/
public static class ImageCacheParams {
public int memCacheSize = DEFAULT_MEM_CACHE_SIZE;
public int compressQuality = DEFAULT_COMPRESS_QUALITY;
public boolean memoryCacheEnabled = DEFAULT_MEM_CACHE_ENABLED;
public boolean initDiskCacheOnCreate = DEFAULT_INIT_DISK_CACHE_ON_CREATE;
/**
* Sets the memory cache size based on a percentage of the max available
* VM memory. Eg. setting percent to 0.2 would set the memory cache to
* one fifth of the available memory. Throws
* {@link IllegalArgumentException} if percent is < 0.01 or > .8.
* memCacheSize is stored in kilobytes instead of bytes as this will
* eventually be passed to construct a LruCache which takes an int in
* its constructor.
*
* This value should be chosen carefully based on a number of factors
* Refer to the corresponding Android Training class for more
* discussion: http://developer.android.com/training/displaying-bitmaps/
*
* @param percent
* Percent of available app memory to use to size memory
* cache
*/
public void setMemCacheSizePercent(float percent) {
if (percent < 0.01f || percent > 0.8f) {
throw new IllegalArgumentException(
"setMemCacheSizePercent - percent must be "
+ "between 0.01 and 0.8 (inclusive)");
}
memCacheSize = Math.round(percent
* Runtime.getRuntime().maxMemory() / 1024);
}
}
/**
* @param candidate
* - Bitmap to check
* @param targetOptions
* - Options that have the out* value populated
* @return true if <code>candidate</code> can be used for inBitmap re-use
* with <code>targetOptions</code>
*/
@TargetApi(19)
private static boolean canUseForInBitmap(Bitmap candidate,
BitmapFactory.Options targetOptions) {
// BEGIN_INCLUDE(can_use_for_inbitmap)
if (!Utils.hasKitKat()) {
// On earlier versions, the dimensions must match exactly and the
// inSampleSize must be 1
return candidate.getWidth() == targetOptions.outWidth
&& candidate.getHeight() == targetOptions.outHeight
&& targetOptions.inSampleSize == 1;
}
// From Android 4.4 (KitKat) onward we can re-use if the byte size of
// the new bitmap
// is smaller than the reusable bitmap candidate allocation byte count.
int width = targetOptions.outWidth / targetOptions.inSampleSize;
int height = targetOptions.outHeight / targetOptions.inSampleSize;
int byteCount = width * height
* getBytesPerPixel(candidate.getConfig());
return byteCount <= candidate.getByteCount();
// END_INCLUDE(can_use_for_inbitmap)
}
/**
* Return the byte usage per pixel of a bitmap based on its configuration.
*
* @param config
* The bitmap configuration.
* @return The byte usage per pixel.
*/
private static int getBytesPerPixel(Config config) {
if (config == Config.ARGB_8888) {
return 4;
} else if (config == Config.RGB_565) {
return 2;
} else if (config == Config.ARGB_4444) {
return 2;
} else if (config == Config.ALPHA_8) {
return 1;
}
return 1;
}
/**
* Get a usable cache directory (external if available, internal otherwise).
*
* @param context
* The context to use
* @param uniqueName
* A unique directory name to append to the cache dir
* @return The cache dir
*/
public static File getDiskCacheDir(Context context, String uniqueName) {
// Check if media is mounted or storage is built-in, if so, try and use
// external cache dir
// otherwise use internal cache dir
final String cachePath = Environment.MEDIA_MOUNTED.equals(Environment
.getExternalStorageState()) || !isExternalStorageRemovable() ? getExternalCacheDir(
context).getPath()
: context.getCacheDir().getPath();
return new File(cachePath + File.separator + uniqueName);
}
/**
* A hashing method that changes a string (like a URL) into a hash suitable
* for using as a disk filename.
*/
public static String hashKeyForDisk(String key) {
String cacheKey;
try {
final MessageDigest mDigest = MessageDigest.getInstance("MD5");
mDigest.update(key.getBytes());
cacheKey = bytesToHexString(mDigest.digest());
} catch (NoSuchAlgorithmException e) {
cacheKey = String.valueOf(key.hashCode());
}
return cacheKey;
}
private static String bytesToHexString(byte[] bytes) {
// http://stackoverflow.com/questions/332079
StringBuilder sb = new StringBuilder();
for (int i = 0; i < bytes.length; i++) {
String hex = Integer.toHexString(0xFF & bytes[i]);
if (hex.length() == 1) {
sb.append('0');
}
sb.append(hex);
}
return sb.toString();
}
/**
* Get the size in bytes of a bitmap in a BitmapDrawable. Note that from
* Android 4.4 (KitKat) onward this returns the allocated memory size of the
* bitmap which can be larger than the actual bitmap data byte count (in the
* case it was re-used).
*
* @param value
* @return size in bytes
*/
@TargetApi(19)
public static int getBitmapSize(BitmapDrawable value) {
Bitmap bitmap = value.getBitmap();
// From KitKat onward use getAllocationByteCount() as allocated bytes
// can potentially be
// larger than bitmap byte count.
// if (Utils.hasKitKat()) {
// return bitmap.getAllocationByteCount();
// }
if (Utils.hasHoneycombMR1()) {
return bitmap.getByteCount();
}
// Pre HC-MR1
return bitmap.getRowBytes() * bitmap.getHeight();
}
/**
* Check if external storage is built-in or removable.
*
* @return True if external storage is removable (like an SD card), false
* otherwise.
*/
@TargetApi(VERSION_CODES.GINGERBREAD)
public static boolean isExternalStorageRemovable() {
if (Utils.hasGingerbread()) {
return Environment.isExternalStorageRemovable();
}
return true;
}
/**
* Get the external app cache directory.
*
* @param context
* The context to use
* @return The external cache dir
*/
@TargetApi(VERSION_CODES.FROYO)
public static File getExternalCacheDir(Context context) {
if (Utils.hasFroyo()) {
return context.getExternalCacheDir();
}
// Before Froyo we need to construct the external cache dir ourselves
final String cacheDir = "/Android/data/" + context.getPackageName()
+ "/cache/";
return new File(Environment.getExternalStorageDirectory().getPath()
+ cacheDir);
}
/**
* Locate an existing instance of this Fragment or if not found, create and
* add it using FragmentManager.
*
* @param fm
* The FragmentManager manager to use.
* @return The existing instance of the Fragment or the new instance if just
* created.
*/
private static RetainFragment findOrCreateRetainFragment(FragmentManager fm) {
// BEGIN_INCLUDE(find_create_retain_fragment)
// Check to see if we have retained the worker fragment.
RetainFragment mRetainFragment = (RetainFragment) fm
.findFragmentByTag(TAG);
// If not retained (or first time running), we need to create and add
// it.
if (mRetainFragment == null) {
mRetainFragment = new RetainFragment();
fm.beginTransaction().add(mRetainFragment, TAG)
.commitAllowingStateLoss();
}
return mRetainFragment;
// END_INCLUDE(find_create_retain_fragment)
}
/**
* A simple non-UI Fragment that stores a single Object and is retained over
* configuration changes. It will be used to retain the ImageCache object.
*/
public static class RetainFragment extends Fragment {
private Object mObject;
/**
* Empty constructor as per the Fragment documentation
*/
public RetainFragment() {
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Make sure this Fragment is retained over a configuration change
setRetainInstance(true);
}
/**
* Store a single object in this Fragment.
*
* @param object
* The object to store
*/
public void setObject(Object object) {
mObject = object;
}
/**
* Get the stored object.
*
* @return The stored object
*/
public Object getObject() {
return mObject;
}
}
}