| // Copyright 2013 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| package org.chromium.base; |
| |
| import android.content.ContentResolver; |
| import android.content.Context; |
| import android.database.Cursor; |
| import android.net.Uri; |
| import android.os.ParcelFileDescriptor; |
| import android.util.Log; |
| |
| import java.io.File; |
| |
| /** |
| * This class provides methods to access content URI schemes. |
| */ |
| public abstract class ContentUriUtils { |
| private static final String TAG = "ContentUriUtils"; |
| private static FileProviderUtil sFileProviderUtil; |
| |
| /** |
| * Provides functionality to translate a file into a content URI for use |
| * with a content provider. |
| */ |
| public interface FileProviderUtil { |
| /** |
| * Generate a content uri from the given file. |
| * @param context Application context. |
| * @param file The file to be translated. |
| */ |
| public Uri getContentUriFromFile(Context context, File file); |
| } |
| |
| // Prevent instantiation. |
| private ContentUriUtils() {} |
| |
| public static void setFileProviderUtil(FileProviderUtil util) { |
| sFileProviderUtil = util; |
| } |
| |
| public static Uri getContentUriFromFile(Context context, File file) { |
| ThreadUtils.assertOnUiThread(); |
| if (sFileProviderUtil != null) { |
| return sFileProviderUtil.getContentUriFromFile(context, file); |
| } |
| return null; |
| } |
| |
| /** |
| * Opens the content URI for reading, and returns the file descriptor to |
| * the caller. The caller is responsible for closing the file desciptor. |
| * |
| * @param context {@link Context} in interest |
| * @param uriString the content URI to open |
| * @returns file desciptor upon sucess, or -1 otherwise. |
| */ |
| @CalledByNative |
| public static int openContentUriForRead(Context context, String uriString) { |
| ParcelFileDescriptor pfd = getParcelFileDescriptor(context, uriString); |
| if (pfd != null) { |
| return pfd.detachFd(); |
| } |
| return -1; |
| } |
| |
| /** |
| * Check whether a content URI exists. |
| * |
| * @param context {@link Context} in interest. |
| * @param uriString the content URI to query. |
| * @returns true if the uri exists, or false otherwise. |
| */ |
| @CalledByNative |
| public static boolean contentUriExists(Context context, String uriString) { |
| ParcelFileDescriptor pfd = getParcelFileDescriptor(context, uriString); |
| if (pfd == null) { |
| return false; |
| } |
| return true; |
| } |
| |
| /** |
| * Helper method to open a content URI and return the ParcelFileDescriptor. |
| * |
| * @param context {@link Context} in interest. |
| * @param uriString the content URI to open. |
| * @returns ParcelFileDescriptor of the content URI, or NULL if the file does not exist. |
| */ |
| private static ParcelFileDescriptor getParcelFileDescriptor(Context context, String uriString) { |
| ContentResolver resolver = context.getContentResolver(); |
| Uri uri = Uri.parse(uriString); |
| |
| ParcelFileDescriptor pfd = null; |
| try { |
| pfd = resolver.openFileDescriptor(uri, "r"); |
| } catch (java.io.FileNotFoundException e) { |
| Log.w(TAG, "Cannot find content uri: " + uriString, e); |
| } |
| return pfd; |
| } |
| |
| /** |
| * Method to resolve the display name of a content URI. |
| * |
| * @param uri the content URI to be resolved. |
| * @param contentResolver the content resolver to query. |
| * @param columnField the column field to query. |
| * @returns the display name of the @code uri if present in the database |
| * or an empty string otherwise. |
| */ |
| public static String getDisplayName( |
| Uri uri, ContentResolver contentResolver, String columnField) { |
| if (contentResolver == null || uri == null) return ""; |
| Cursor cursor = null; |
| try { |
| cursor = contentResolver.query(uri, null, null, null, null); |
| |
| if (cursor != null && cursor.getCount() >= 1) { |
| cursor.moveToFirst(); |
| int index = cursor.getColumnIndex(columnField); |
| if (index > -1) return cursor.getString(index); |
| } |
| } catch (NullPointerException e) { |
| // Some android models don't handle the provider call correctly. |
| // see crbug.com/345393 |
| return ""; |
| } finally { |
| if (cursor != null) cursor.close(); |
| } |
| return ""; |
| } |
| } |