Android Open Source - base-android-utils Storage Utils

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/*******************************************************************************
 * Copyright 2011-2014 Sergey Tarasevich
 *//from  w w  w . j  a  va 2  s  .  c  o  m
 * 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 me.pc.mobile.helper.v14.util;

import android.content.Context;
import android.content.pm.PackageManager;
import android.os.Environment;

import java.io.File;
import java.io.IOException;

import static android.os.Environment.MEDIA_MOUNTED;

/**
 * Provides application storage paths
 * 
 * @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
 * @since 1.0.0
 */
public final class StorageUtils {
  private static final String TAG = StorageUtils.class.getSimpleName();

  private static final String EXTERNAL_STORAGE_PERMISSION = "android.permission.WRITE_EXTERNAL_STORAGE";
  private static final String INDIVIDUAL_DIR_NAME = "uil-images";

  private StorageUtils() {
  }

  /**
   * Returns application cache directory. Cache directory will be created on
   * SD card <i>("/Android/data/[app_package_name]/cache")</i> if card is
   * mounted and app has appropriate permission. Else - Android defines cache
   * directory on device's file system.
   * 
   * @param context
   *            Application context
   * @return Cache {@link File directory}.<br />
   *         <b>NOTE:</b> Can be null in some unpredictable cases (if SD card
   *         is unmounted and {@link android.content.Context#getCacheDir()
   *         Context.getCacheDir()} returns null).
   */
  public static File getCacheDirectory(Context context) {
    return getCacheDirectory(context, true);
  }

  /**
   * Returns application cache directory. Cache directory will be created on
   * SD card <i>("/Android/data/[app_package_name]/cache")</i> (if card is
   * mounted and app has appropriate permission) or on device's file system
   * depending incoming parameters.
   * 
   * @param context
   *            Application context
   * @param preferExternal
   *            Whether prefer external location for cache
   * @return Cache {@link File directory}.<br />
   *         <b>NOTE:</b> Can be null in some unpredictable cases (if SD card
   *         is unmounted and {@link android.content.Context#getCacheDir()
   *         Context.getCacheDir()} returns null).
   */
  public static File getCacheDirectory(Context context, boolean preferExternal) {
    File appCacheDir = null;
    String externalStorageState;
    try {
      externalStorageState = Environment.getExternalStorageState();
    } catch (NullPointerException e) { // (sh)it happens (Issue #660)
      externalStorageState = "";
    }
    if (preferExternal && MEDIA_MOUNTED.equals(externalStorageState)
        && hasExternalStoragePermission(context)) {
      appCacheDir = getExternalCacheDir(context);
    }
    if (appCacheDir == null) {
      appCacheDir = context.getCacheDir();
    }
    if (appCacheDir == null) {
      String cacheDirPath = "/data/data/" + context.getPackageName()
          + "/cache/";
      LogUtil.warn(
          "Can't define system cache directory! '%s' will be used.",
          cacheDirPath);
      appCacheDir = new File(cacheDirPath);
    }
    return appCacheDir;
  }

  /**
   * Returns individual application cache directory (for only image caching
   * from ImageLoader). Cache directory will be created on SD card
   * <i>("/Android/data/[app_package_name]/cache/uil-images")</i> if card is
   * mounted and app has appropriate permission. Else - Android defines cache
   * directory on device's file system.
   * 
   * @param context
   *            Application context
   * @return Cache {@link File directory}
   */
  public static File getIndividualCacheDirectory(Context context) {
    File cacheDir = getCacheDirectory(context);
    File individualCacheDir = new File(cacheDir, INDIVIDUAL_DIR_NAME);
    if (!individualCacheDir.exists()) {
      if (!individualCacheDir.mkdir()) {
        individualCacheDir = cacheDir;
      }
    }
    return individualCacheDir;
  }

  /**
   * Returns specified application cache directory. Cache directory will be
   * created on SD card by defined path if card is mounted and app has
   * appropriate permission. Else - Android defines cache directory on
   * device's file system.
   * 
   * @param context
   *            Application context
   * @param cacheDir
   *            Cache directory path (e.g.: "AppCacheDir",
   *            "AppDir/cache/images")
   * @return Cache {@link File directory}
   */
  public static File getOwnCacheDirectory(Context context, String cacheDir) {
    File appCacheDir = null;
    if (MEDIA_MOUNTED.equals(Environment.getExternalStorageState())
        && hasExternalStoragePermission(context)) {
      appCacheDir = new File(Environment.getExternalStorageDirectory(),
          cacheDir);
    }
    if (appCacheDir == null
        || (!appCacheDir.exists() && !appCacheDir.mkdirs())) {
      appCacheDir = context.getCacheDir();
    }
    return appCacheDir;
  }

  private static File getExternalCacheDir(Context context) {
    File dataDir = new File(new File(
        Environment.getExternalStorageDirectory(), "Android"), "data");
    File appCacheDir = new File(
        new File(dataDir, context.getPackageName()), "cache");
    if (!appCacheDir.exists()) {
      if (!appCacheDir.mkdirs()) {
        LogUtil.warn(TAG, "Unable to create external cache directory");
        return null;
      }
      try {
        new File(appCacheDir, ".nomedia").createNewFile();
      } catch (IOException e) {
        LogUtil.warn(TAG,
            "Can't create \".nomedia\" file in application external cache directory");
      }
    }
    return appCacheDir;
  }

  private static boolean hasExternalStoragePermission(Context context) {
    int perm = context
        .checkCallingOrSelfPermission(EXTERNAL_STORAGE_PERMISSION);
    return perm == PackageManager.PERMISSION_GRANTED;
  }
}

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