space-android/src/main/java/com/owncloud/android/ui/adapter/DiskLruImageCache.java

/**
 *   ownCloud Android client application
 *
 *   Copyright (C) 2015 ownCloud Inc.
 *
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License version 2,
 *   as published by the Free Software Foundation.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

package com.owncloud.android.ui.adapter;

import android.graphics.Bitmap;
import android.graphics.Bitmap.CompressFormat;
import android.graphics.BitmapFactory;

import com.jakewharton.disklrucache.DiskLruCache;
import com.owncloud.android.BuildConfig;
import com.owncloud.android.lib.common.utils.Log_OC;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class DiskLruImageCache {

    private DiskLruCache mDiskCache;
    private CompressFormat mCompressFormat;
    private int mCompressQuality;
    private static final int CACHE_VERSION = 1;
    private static final int VALUE_COUNT = 1;
    private static final int IO_BUFFER_SIZE = 8 * 1024;
    private static final String CACHE_TEST_DISK = "cache_test_DISK_";
            
    private static final String TAG = DiskLruImageCache.class.getSimpleName();

    //public DiskLruImageCache( Context context,String uniqueName, int diskCacheSize,
    public DiskLruImageCache(
            File diskCacheDir, int diskCacheSize, CompressFormat compressFormat, int quality 
            ) throws IOException {

        mDiskCache = DiskLruCache.open(
                diskCacheDir, CACHE_VERSION, VALUE_COUNT, diskCacheSize 
        );
        mCompressFormat = compressFormat;
        mCompressQuality = quality;
    }

    private boolean writeBitmapToFile( Bitmap bitmap, DiskLruCache.Editor editor )
        throws IOException, FileNotFoundException {
        OutputStream out = null;
        try {
            out = new BufferedOutputStream( editor.newOutputStream( 0 ), IO_BUFFER_SIZE );
            return bitmap.compress( mCompressFormat, mCompressQuality, out );
        } finally {
            if ( out != null ) {
                out.close();
            }
        }
    }

    public void put( String key, Bitmap data ) {

        DiskLruCache.Editor editor = null;
        String validKey = convertToValidKey(key);
        try {
            editor = mDiskCache.edit( validKey );
            if ( editor == null ) {
                return;
            }

            if( writeBitmapToFile( data, editor ) ) {               
                mDiskCache.flush();
                editor.commit();
                if ( BuildConfig.DEBUG ) {
                   Log_OC.d( CACHE_TEST_DISK, "image put on disk cache " + validKey );
                }
            } else {
                editor.abort();
                if ( BuildConfig.DEBUG ) {
                    Log_OC.d( CACHE_TEST_DISK, "ERROR on: image put on disk cache " + validKey );
                }
            }   
        } catch (IOException e) {
            if ( BuildConfig.DEBUG ) {
                Log_OC.d( CACHE_TEST_DISK, "ERROR on: image put on disk cache " + validKey );
            }
            try {
                if ( editor != null ) {
                    editor.abort();
                }
            } catch (IOException ignored) {
            }           
        }

    }

    public Bitmap getBitmap( String key ) {

        Bitmap bitmap = null;
        DiskLruCache.Snapshot snapshot = null;
        String validKey = convertToValidKey(key);
        try {

            snapshot = mDiskCache.get( validKey );
            if ( snapshot == null ) {
                return null;
            }
            final InputStream in = snapshot.getInputStream( 0 );
            if ( in != null ) {
                final BufferedInputStream buffIn = 
                new BufferedInputStream( in, IO_BUFFER_SIZE );
                bitmap = BitmapFactory.decodeStream( buffIn );              
            }   
        } catch ( IOException e ) {
            Log_OC.d(TAG, e.getMessage(), e);
        } finally {
            if (snapshot != null) {
                snapshot.close();
            }
        }

        if ( BuildConfig.DEBUG ) {
            Log_OC.d(CACHE_TEST_DISK, bitmap == null ?
                    "not found" : "image read from disk " + validKey);
        }

        return bitmap;

    }

    public boolean containsKey( String key ) {

        boolean contained = false;
        DiskLruCache.Snapshot snapshot = null;
        String validKey = convertToValidKey(key);
        try {
            snapshot = mDiskCache.get( validKey );
            contained = snapshot != null;
        } catch (IOException e) {
            Log_OC.d(TAG, e.getMessage(), e);
        } finally {
            if (snapshot != null) {
                snapshot.close();
            }
        }

        return contained;

    }

    public void clearCache() {
        if ( BuildConfig.DEBUG ) {
            Log_OC.d( CACHE_TEST_DISK, "disk cache CLEARED");
        }
        try {
            mDiskCache.delete();
        } catch ( IOException e ) {
            Log_OC.d(TAG, e.getMessage(), e);
        }
    }

    public File getCacheFolder() {
        return mDiskCache.getDirectory();
    }
    
    private String convertToValidKey(String key) {
        return Integer.toString(key.hashCode());
    }

    /**
     * Remove passed key from cache
     * @param key
     */
    public void removeKey( String key ) {
        String validKey = convertToValidKey(key);
        try {
            mDiskCache.remove(validKey);
            Log_OC.d(TAG, "removeKey from cache: " + validKey);
        } catch (IOException e) {
            Log_OC.d(TAG, e.getMessage(), e);
        }
    }
}