/*******************************************************************************
* Copyright 2014 Sergey Tarasevich
*
* 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.nostra13.universalimageloader.cache.disc.impl.ext;
import android.graphics.Bitmap;
import com.nostra13.universalimageloader.cache.disc.DiskCache;
import com.nostra13.universalimageloader.cache.disc.naming.FileNameGenerator;
import com.nostra13.universalimageloader.utils.IoUtils;
import com.nostra13.universalimageloader.utils.L;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
/**
* 基于LRU算法文件缓存 实现DiskCache接口
* Disk cache based on "Least-Recently Used" principle. Adapter pattern, adapts
* {@link com.nostra13.universalimageloader.cache.disc.impl.ext.DiskLruCache DiskLruCache} to
* {@link com.nostra13.universalimageloader.cache.disc.DiskCache DiskCache}
*
* @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
* @see FileNameGenerator
* @since 1.9.2
*/
public class LruDiskCache implements DiskCache {
/**
* {@value}
* 默认缓冲区大小
*/
public static final int DEFAULT_BUFFER_SIZE = 32 * 1024; // 32 Kb
/**
* {@value}
* 图片压缩格式
* */
public static final Bitmap.CompressFormat DEFAULT_COMPRESS_FORMAT = Bitmap.CompressFormat.PNG;
/** {@value}
* 默认图片压缩质量
*/
public static final int DEFAULT_COMPRESS_QUALITY = 100;
private static final String ERROR_ARG_NULL = " argument must be not null";
private static final String ERROR_ARG_NEGATIVE = " argument must be positive number";
/*本地文件系统(磁盘)LRU缓存器*/
protected DiskLruCache cache;
/*备用缓存文件*/
private File reserveCacheDir;
/*缓存文件名 命名生成器*/
protected final FileNameGenerator fileNameGenerator;
/*缓冲区 这边已经进行复制初始化*/
protected int bufferSize = DEFAULT_BUFFER_SIZE;
/*图片压缩质量 这边赋值默认数据*/
protected Bitmap.CompressFormat compressFormat = DEFAULT_COMPRESS_FORMAT;
protected int compressQuality = DEFAULT_COMPRESS_QUALITY;
/**
* LruDiskCache 图片本地文件缓存器初始化
* @param cacheDir Directory for file caching
* @param fileNameGenerator {@linkplain com.nostra13.universalimageloader.cache.disc.naming.FileNameGenerator
* Name generator} for cached files. Generated names must match the regex
* <strong>[a-z0-9_-]{1,64}</strong>
* @param cacheMaxSize Max cache size in bytes. <b>0</b> means cache size is unlimited.
* @throws IOException if cache can't be initialized (e.g. "No space left on device")
*/
/**
* LruDiskCache 图片本地文件缓存器初始化
* @param cacheDir 缓存器文件
* @param fileNameGenerator 缓存文件名命名规则生成器
* @param cacheMaxSize 最大缓存大小
* @throws IOException
*/
public LruDiskCache(File cacheDir, FileNameGenerator fileNameGenerator, long cacheMaxSize) throws IOException {
this(cacheDir, null, fileNameGenerator, cacheMaxSize, 0);
}
/**
* LruDiskCache 图片本地文件缓存器初始化
* @param cacheDir Directory for file caching
* @param reserveCacheDir null-ok; Reserve directory for file caching. It's used when the primary directory isn't available.
* @param fileNameGenerator {@linkplain com.nostra13.universalimageloader.cache.disc.naming.FileNameGenerator
* Name generator} for cached files. Generated names must match the regex
* <strong>[a-z0-9_-]{1,64}</strong>
* @param cacheMaxSize Max cache size in bytes. <b>0</b> means cache size is unlimited.
* @param cacheMaxFileCount Max file count in cache. <b>0</b> means file count is unlimited.
* @throws IOException if cache can't be initialized (e.g. "No space left on device")
*/
public LruDiskCache(File cacheDir, File reserveCacheDir, FileNameGenerator fileNameGenerator, long cacheMaxSize,
int cacheMaxFileCount) throws IOException {
if (cacheDir == null) {
throw new IllegalArgumentException("cacheDir" + ERROR_ARG_NULL);
}
if (cacheMaxSize < 0) {
throw new IllegalArgumentException("cacheMaxSize" + ERROR_ARG_NEGATIVE);
}
if (cacheMaxFileCount < 0) {
throw new IllegalArgumentException("cacheMaxFileCount" + ERROR_ARG_NEGATIVE);
}
if (fileNameGenerator == null) {
throw new IllegalArgumentException("fileNameGenerator" + ERROR_ARG_NULL);
}
//如果传入最大缓存大小为0 ,那么设置Long的最大值
if (cacheMaxSize == 0) {
cacheMaxSize = Long.MAX_VALUE;
}
//如果传入最大缓存文件数量为0 ，那么设置Integer的最大值
if (cacheMaxFileCount == 0) {
cacheMaxFileCount = Integer.MAX_VALUE;
}
this.reserveCacheDir = reserveCacheDir;
this.fileNameGenerator = fileNameGenerator;
//初始化缓存
initCache(cacheDir, reserveCacheDir, cacheMaxSize, cacheMaxFileCount);
}
/**
* 初始化本地文件 图片缓存器
* @param cacheDir 图片缓存路径
* @param reserveCacheDir 备用图片缓存路径
* @param cacheMaxSize 最大缓存大小
* @param cacheMaxFileCount 最大缓存图片数量
* @throws IOException
*/
private void initCache(File cacheDir, File reserveCacheDir, long cacheMaxSize, int cacheMaxFileCount)
throws IOException {
try {
cache = DiskLruCache.open(cacheDir, 1, 1, cacheMaxSize, cacheMaxFileCount);
} catch (IOException e) {
L.e(e);
if (reserveCacheDir != null) {
initCache(reserveCacheDir, null, cacheMaxSize, cacheMaxFileCount);
}
if (cache == null) {
throw e; //new RuntimeException("Can't initialize disk cache", e);
}
}
}
/**
* 获取LRU文件缓存文件路径
* @return
*/
@Override
public File getDirectory() {
return cache.getDirectory();
}
/**
* 根据的URL连接 从LRU文件器重获取文件
* @param imageUri Original image URI
* @return
*/
@Override
public File get(String imageUri) {
DiskLruCache.Snapshot snapshot = null;
try {
snapshot = cache.get(getKey(imageUri));
return snapshot == null ? null : snapshot.getFile(0);
} catch (IOException e) {
L.e(e);
return null;
} finally {
if (snapshot != null) {
snapshot.close();
}
}
}
/**
* 把图片流数据保存到缓存中
* @param imageUri Original image URI 图像URL连接地址
* @param imageStream Input stream of image (shouldn't be closed in this method) 图片流
* @param listener 图片流拷贝监听器
* Listener for saving progress, can be ignored if you don't use
* {@linkplain com.nostra13.universalimageloader.core.listener.ImageLoadingProgressListener
* progress listener} in ImageLoader calls
* @return
* @throws IOException
*/
@Override
public boolean save(String imageUri, InputStream imageStream, IoUtils.CopyListener listener) throws IOException {
DiskLruCache.Editor editor = cache.edit(getKey(imageUri));
if (editor == null) {
return false;
}
//流写入文件
OutputStream os = new BufferedOutputStream(editor.newOutputStream(0), bufferSize);
boolean copied = false;
try {
copied = IoUtils.copyStream(imageStream, os, listener, bufferSize);
} finally {
IoUtils.closeSilently(os);
if (copied) {
editor.commit();
} else {
editor.abort();
}
}
return copied;
}
/**
* 把图片bitmap存入到缓存器中
* @param imageUri Original image URI 图片URL地址
* @param bitmap Image bitmap 需要保存的图片
* @return
* @throws IOException
*/
@Override
public boolean save(String imageUri, Bitmap bitmap) throws IOException {
DiskLruCache.Editor editor = cache.edit(getKey(imageUri));
if (editor == null) {
return false;
}
//流写入文件
OutputStream os = new BufferedOutputStream(editor.newOutputStream(0), bufferSize);
boolean savedSuccessfully = false;
try {
savedSuccessfully = bitmap.compress(compressFormat, compressQuality, os);
} finally {
IoUtils.closeSilently(os);
}
if (savedSuccessfully) {
editor.commit();
} else {
editor.abort();
}
return savedSuccessfully;
}
/**
* 根据图片URL地址从缓存中删除文件
* @param imageUri Image URI
* @return
*/
@Override
public boolean remove(String imageUri) {
try {
return cache.remove(getKey(imageUri));
} catch (IOException e) {
L.e(e);
return false;
}
}
/**
* 进行关闭缓存
*/
@Override
public void close() {
try {
cache.close();
} catch (IOException e) {
L.e(e);
}
cache = null;
}
/**
* 进行清除缓存数据
*/
@Override
public void clear() {
try {
cache.delete();
} catch (IOException e) {
L.e(e);
}
try {
//这边重新初始化缓存器 缓存器中文件为空
initCache(cache.getDirectory(), reserveCacheDir, cache.getMaxSize(), cache.getMaxFileCount());
} catch (IOException e) {
L.e(e);
}
}
/**
* 根据图片URL地址进行生成缓存文件名
* @param imageUri
* @return
*/
private String getKey(String imageUri) {
return fileNameGenerator.generate(imageUri);
}
/**
* 设置缓冲区大小
* @param bufferSize
*/
public void setBufferSize(int bufferSize) {
this.bufferSize = bufferSize;
}
/**
* 设置图片压缩格式
* @param compressFormat
*/
public void setCompressFormat(Bitmap.CompressFormat compressFormat) {
this.compressFormat = compressFormat;
}
/**
* 设置图片压缩质量
* @param compressQuality
*/
public void setCompressQuality(int compressQuality) {
this.compressQuality = compressQuality;
}
}
