usbtuner/src/com/android/usbtuner/exoplayer/cache/TrickplayStorageManager.java

/*
 * Copyright (C) 2015 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.usbtuner.exoplayer.cache;

import android.content.Context;
import android.media.MediaFormat;
import android.provider.Settings;
import android.util.Pair;

import java.io.File;
import java.util.ArrayList;
import java.util.SortedMap;

/**
 * Manages Trickplay storage.
 */
public class TrickplayStorageManager implements CacheManager.StorageManager {
    private static final String CACHE_DIR = "timeshift";

    // Copied from android.provider.Settings.Global (hidden fields)
    private static final String
            SYS_STORAGE_THRESHOLD_PERCENTAGE = "sys_storage_threshold_percentage";
    private static final String
            SYS_STORAGE_THRESHOLD_MAX_BYTES = "sys_storage_threshold_max_bytes";

    // Copied from android.os.StorageManager
    private static final int DEFAULT_THRESHOLD_PERCENTAGE = 10;
    private static final long DEFAULT_THRESHOLD_MAX_BYTES = 500L * 1024 * 1024;

    private final File mCacheDir;
    private final long mMaxCacheSize;
    private final long mStorageBufferBytes;

    private static long getStorageBufferBytes(Context context, File path) {
        long lowPercentage = Settings.Global.getInt(context.getContentResolver(),
                SYS_STORAGE_THRESHOLD_PERCENTAGE, DEFAULT_THRESHOLD_PERCENTAGE);
        long lowBytes = path.getTotalSpace() * lowPercentage / 100;
        long maxLowBytes = Settings.Global.getLong(context.getContentResolver(),
                SYS_STORAGE_THRESHOLD_MAX_BYTES, DEFAULT_THRESHOLD_MAX_BYTES);
        return Math.min(lowBytes, maxLowBytes);
    }

    public TrickplayStorageManager(Context context, File baseDir, long maxCacheSize) {
        mCacheDir = new File(baseDir, CACHE_DIR);
        mCacheDir.mkdirs();
        mMaxCacheSize = maxCacheSize;
        clearStorage();
        mStorageBufferBytes = getStorageBufferBytes(context, mCacheDir);
    }

    @Override
    public void clearStorage() {
        for (File file : mCacheDir.listFiles()) {
            file.delete();
        }
    }

    @Override
    public File getCacheDir() {
        return mCacheDir;
    }

    @Override
    public boolean isPersistent() {
        return false;
    }

    @Override
    public boolean reachedStorageMax(long cacheSize, long pendingDelete) {
        return cacheSize - pendingDelete > mMaxCacheSize;
    }

    @Override
    public boolean hasEnoughBuffer(long pendingDelete) {
        return mCacheDir.getUsableSpace() + pendingDelete >= mStorageBufferBytes;
    }

    @Override
    public Pair<String, MediaFormat> readTrackInfoFile(boolean isAudio) {
        return null;
    }

    @Override
    public ArrayList<Long> readIndexFile(String trackId) {
        return null;
    }

    @Override
    public void writeTrackInfoFile(String trackId, MediaFormat format, boolean isAudio) {
    }

    @Override
    public void writeIndexFile(String trackName, SortedMap<Long, SampleCache> index) {
    }

}