| /* |
| * Copyright (C) 2013 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 android.support.v4.content; |
| |
| import static org.xmlpull.v1.XmlPullParser.END_DOCUMENT; |
| import static org.xmlpull.v1.XmlPullParser.START_TAG; |
| |
| import android.content.ContentProvider; |
| import android.content.ContentValues; |
| import android.content.Context; |
| import android.content.Intent; |
| import android.content.pm.PackageManager; |
| import android.content.pm.ProviderInfo; |
| import android.content.res.XmlResourceParser; |
| import android.database.Cursor; |
| import android.database.MatrixCursor; |
| import android.net.Uri; |
| import android.os.Environment; |
| import android.os.ParcelFileDescriptor; |
| import android.provider.OpenableColumns; |
| import android.text.TextUtils; |
| import android.webkit.MimeTypeMap; |
| |
| import org.xmlpull.v1.XmlPullParserException; |
| |
| import java.io.File; |
| import java.io.FileNotFoundException; |
| import java.io.IOException; |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| /** |
| * FileProvider is a special subclass of {@link ContentProvider} that facilitates secure sharing |
| * of files associated with an app by creating a <code>content://</code> {@link Uri} for a file |
| * instead of a <code>file:///</code> {@link Uri}. |
| * <p> |
| * A content URI allows you to grant read and write access using |
| * temporary access permissions. When you create an {@link Intent} containing |
| * a content URI, in order to send the content URI |
| * to a client app, you can also call {@link Intent#setFlags(int) Intent.setFlags()} to add |
| * permissions. These permissions are available to the client app for as long as the stack for |
| * a receiving {@link android.app.Activity} is active. For an {@link Intent} going to a |
| * {@link android.app.Service}, the permissions are available as long as the |
| * {@link android.app.Service} is running. |
| * <p> |
| * In comparison, to control access to a <code>file:///</code> {@link Uri} you have to modify the |
| * file system permissions of the underlying file. The permissions you provide become available to |
| * <em>any</em> app, and remain in effect until you change them. This level of access is |
| * fundamentally insecure. |
| * <p> |
| * The increased level of file access security offered by a content URI |
| * makes FileProvider a key part of Android's security infrastructure. |
| * <p> |
| * This overview of FileProvider includes the following topics: |
| * </p> |
| * <ol> |
| * <li><a href="#ProviderDefinition">Defining a FileProvider</a></li> |
| * <li><a href="#SpecifyFiles">Specifying Available Files</a></li> |
| * <li><a href="#GetUri">Retrieving the Content URI for a File</li> |
| * <li><a href="#Permissions">Granting Temporary Permissions to a URI</a></li> |
| * <li><a href="#ServeUri">Serving a Content URI to Another App</a></li> |
| * </ol> |
| * <h3 id="ProviderDefinition">Defining a FileProvider</h3> |
| * <p> |
| * Since the default functionality of FileProvider includes content URI generation for files, you |
| * don't need to define a subclass in code. Instead, you can include a FileProvider in your app |
| * by specifying it entirely in XML. To specify the FileProvider component itself, add a |
| * <code><a href="{@docRoot}guide/topics/manifest/provider-element.html"><provider></a></code> |
| * element to your app manifest. Set the <code>android:name</code> attribute to |
| * <code>android.support.v4.content.FileProvider</code>. Set the <code>android:authorities</code> |
| * attribute to a URI authority based on a domain you control; for example, if you control the |
| * domain <code>mydomain.com</code> you should use the authority |
| * <code>com.mydomain.fileprovider</code>. Set the <code>android:exported</code> attribute to |
| * <code>false</code>; the FileProvider does not need to be public. Set the |
| * <a href="{@docRoot}guide/topics/manifest/provider-element.html#gprmsn" |
| * >android:grantUriPermissions</a> attribute to <code>true</code>, to allow you |
| * to grant temporary access to files. For example: |
| * <pre class="prettyprint"> |
| *<manifest> |
| * ... |
| * <application> |
| * ... |
| * <provider |
| * android:name="android.support.v4.content.FileProvider" |
| * android:authorities="com.mydomain.fileprovider" |
| * android:exported="false" |
| * android:grantUriPermissions="true"> |
| * ... |
| * </provider> |
| * ... |
| * </application> |
| *</manifest></pre> |
| * <p> |
| * If you want to override any of the default behavior of FileProvider methods, extend |
| * the FileProvider class and use the fully-qualified class name in the <code>android:name</code> |
| * attribute of the <code><provider></code> element. |
| * <h3 id="SpecifyFiles">Specifying Available Files</h3> |
| * A FileProvider can only generate a content URI for files in directories that you specify |
| * beforehand. To specify a directory, specify the its storage area and path in XML, using child |
| * elements of the <code><paths></code> element. |
| * For example, the following <code>paths</code> element tells FileProvider that you intend to |
| * request content URIs for the <code>images/</code> subdirectory of your private file area. |
| * <pre class="prettyprint"> |
| *<paths xmlns:android="http://schemas.android.com/apk/res/android"> |
| * <files-path name="my_images" path="images/"/> |
| * ... |
| *</paths> |
| *</pre> |
| * <p> |
| * The <code><paths></code> element must contain one or more of the following child elements: |
| * </p> |
| * <dl> |
| * <dt> |
| * <pre class="prettyprint"> |
| *<files-path name="<i>name</i>" path="<i>path</i>" /> |
| *</pre> |
| * </dt> |
| * <dd> |
| * Represents files in the <code>files/</code> subdirectory of your app's internal storage |
| * area. This subdirectory is the same as the value returned by {@link Context#getFilesDir() |
| * Context.getFilesDir()}. |
| * </dd> |
| * <dt> |
| * <pre> |
| *<cache-path name="<i>name</i>" path="<i>path</i>" /> |
| *</pre> |
| * <dt> |
| * <dd> |
| * Represents files in the cache subdirectory of your app's internal storage area. The root path |
| * of this subdirectory is the same as the value returned by {@link Context#getCacheDir() |
| * getCacheDir()}. |
| * </dd> |
| * <dt> |
| * <pre class="prettyprint"> |
| *<external-path name="<i>name</i>" path="<i>path</i>" /> |
| *</pre> |
| * </dt> |
| * <dd> |
| * Represents files in the root of the external storage area. The root path of this subdirectory |
| * is the same as the value returned by |
| * {@link Environment#getExternalStorageDirectory() Environment.getExternalStorageDirectory()}. |
| * </dd> |
| * <dt> |
| * <pre class="prettyprint"> |
| *<external-files-path name="<i>name</i>" path="<i>path</i>" /> |
| *</pre> |
| * </dt> |
| * <dd> |
| * Represents files in the root of your app's external storage area. The root path of this |
| * subdirectory is the same as the value returned by |
| * {@code Context#getExternalFilesDir(String) Context.getExternalFilesDir(null)}. |
| * </dd> |
| * <dt> |
| * <pre class="prettyprint"> |
| *<external-cache-path name="<i>name</i>" path="<i>path</i>" /> |
| *</pre> |
| * </dt> |
| * <dd> |
| * Represents files in the root of your app's external cache area. The root path of this |
| * subdirectory is the same as the value returned by |
| * {@link Context#getExternalCacheDir() Context.getExternalCacheDir()}. |
| * </dd> |
| * </dl> |
| * <p> |
| * These child elements all use the same attributes: |
| * </p> |
| * <dl> |
| * <dt> |
| * <code>name="<i>name</i>"</code> |
| * </dt> |
| * <dd> |
| * A URI path segment. To enforce security, this value hides the name of the subdirectory |
| * you're sharing. The subdirectory name for this value is contained in the |
| * <code>path</code> attribute. |
| * </dd> |
| * <dt> |
| * <code>path="<i>path</i>"</code> |
| * </dt> |
| * <dd> |
| * The subdirectory you're sharing. While the <code>name</code> attribute is a URI path |
| * segment, the <code>path</code> value is an actual subdirectory name. Notice that the |
| * value refers to a <b>subdirectory</b>, not an individual file or files. You can't |
| * share a single file by its file name, nor can you specify a subset of files using |
| * wildcards. |
| * </dd> |
| * </dl> |
| * <p> |
| * You must specify a child element of <code><paths></code> for each directory that contains |
| * files for which you want content URIs. For example, these XML elements specify two directories: |
| * <pre class="prettyprint"> |
| *<paths xmlns:android="http://schemas.android.com/apk/res/android"> |
| * <files-path name="my_images" path="images/"/> |
| * <files-path name="my_docs" path="docs/"/> |
| *</paths> |
| *</pre> |
| * <p> |
| * Put the <code><paths></code> element and its children in an XML file in your project. |
| * For example, you can add them to a new file called <code>res/xml/file_paths.xml</code>. |
| * To link this file to the FileProvider, add a |
| * <a href="{@docRoot}guide/topics/manifest/meta-data-element.html"><meta-data></a> element |
| * as a child of the <code><provider></code> element that defines the FileProvider. Set the |
| * <code><meta-data></code> element's "android:name" attribute to |
| * <code>android.support.FILE_PROVIDER_PATHS</code>. Set the element's "android:resource" attribute |
| * to <code>@xml/file_paths</code> (notice that you don't specify the <code>.xml</code> |
| * extension). For example: |
| * <pre class="prettyprint"> |
| *<provider |
| * android:name="android.support.v4.content.FileProvider" |
| * android:authorities="com.mydomain.fileprovider" |
| * android:exported="false" |
| * android:grantUriPermissions="true"> |
| * <meta-data |
| * android:name="android.support.FILE_PROVIDER_PATHS" |
| * android:resource="@xml/file_paths" /> |
| *</provider> |
| *</pre> |
| * <h3 id="GetUri">Generating the Content URI for a File</h3> |
| * <p> |
| * To share a file with another app using a content URI, your app has to generate the content URI. |
| * To generate the content URI, create a new {@link File} for the file, then pass the {@link File} |
| * to {@link #getUriForFile(Context, String, File) getUriForFile()}. You can send the content URI |
| * returned by {@link #getUriForFile(Context, String, File) getUriForFile()} to another app in an |
| * {@link android.content.Intent}. The client app that receives the content URI can open the file |
| * and access its contents by calling |
| * {@link android.content.ContentResolver#openFileDescriptor(Uri, String) |
| * ContentResolver.openFileDescriptor} to get a {@link ParcelFileDescriptor}. |
| * <p> |
| * For example, suppose your app is offering files to other apps with a FileProvider that has the |
| * authority <code>com.mydomain.fileprovider</code>. To get a content URI for the file |
| * <code>default_image.jpg</code> in the <code>images/</code> subdirectory of your internal storage |
| * add the following code: |
| * <pre class="prettyprint"> |
| *File imagePath = new File(Context.getFilesDir(), "images"); |
| *File newFile = new File(imagePath, "default_image.jpg"); |
| *Uri contentUri = getUriForFile(getContext(), "com.mydomain.fileprovider", newFile); |
| *</pre> |
| * As a result of the previous snippet, |
| * {@link #getUriForFile(Context, String, File) getUriForFile()} returns the content URI |
| * <code>content://com.mydomain.fileprovider/my_images/default_image.jpg</code>. |
| * <h3 id="Permissions">Granting Temporary Permissions to a URI</h3> |
| * To grant an access permission to a content URI returned from |
| * {@link #getUriForFile(Context, String, File) getUriForFile()}, do one of the following: |
| * <ul> |
| * <li> |
| * Call the method |
| * {@link Context#grantUriPermission(String, Uri, int) |
| * Context.grantUriPermission(package, Uri, mode_flags)} for the <code>content://</code> |
| * {@link Uri}, using the desired mode flags. This grants temporary access permission for the |
| * content URI to the specified package, according to the value of the |
| * the <code>mode_flags</code> parameter, which you can set to |
| * {@link Intent#FLAG_GRANT_READ_URI_PERMISSION}, {@link Intent#FLAG_GRANT_WRITE_URI_PERMISSION} |
| * or both. The permission remains in effect until you revoke it by calling |
| * {@link Context#revokeUriPermission(Uri, int) revokeUriPermission()} or until the device |
| * reboots. |
| * </li> |
| * <li> |
| * Put the content URI in an {@link Intent} by calling {@link Intent#setData(Uri) setData()}. |
| * </li> |
| * <li> |
| * Next, call the method {@link Intent#setFlags(int) Intent.setFlags()} with either |
| * {@link Intent#FLAG_GRANT_READ_URI_PERMISSION} or |
| * {@link Intent#FLAG_GRANT_WRITE_URI_PERMISSION} or both. |
| * </li> |
| * <li> |
| * Finally, send the {@link Intent} to |
| * another app. Most often, you do this by calling |
| * {@link android.app.Activity#setResult(int, android.content.Intent) setResult()}. |
| * <p> |
| * Permissions granted in an {@link Intent} remain in effect while the stack of the receiving |
| * {@link android.app.Activity} is active. When the stack finishes, the permissions are |
| * automatically removed. Permissions granted to one {@link android.app.Activity} in a client |
| * app are automatically extended to other components of that app. |
| * </p> |
| * </li> |
| * </ul> |
| * <h3 id="ServeUri">Serving a Content URI to Another App</h3> |
| * <p> |
| * There are a variety of ways to serve the content URI for a file to a client app. One common way |
| * is for the client app to start your app by calling |
| * {@link android.app.Activity#startActivityForResult(Intent, int, Bundle) startActivityResult()}, |
| * which sends an {@link Intent} to your app to start an {@link android.app.Activity} in your app. |
| * In response, your app can immediately return a content URI to the client app or present a user |
| * interface that allows the user to pick a file. In the latter case, once the user picks the file |
| * your app can return its content URI. In both cases, your app returns the content URI in an |
| * {@link Intent} sent via {@link android.app.Activity#setResult(int, Intent) setResult()}. |
| * </p> |
| * <p> |
| * You can also put the content URI in a {@link android.content.ClipData} object and then add the |
| * object to an {@link Intent} you send to a client app. To do this, call |
| * {@link Intent#setClipData(ClipData) Intent.setClipData()}. When you use this approach, you can |
| * add multiple {@link android.content.ClipData} objects to the {@link Intent}, each with its own |
| * content URI. When you call {@link Intent#setFlags(int) Intent.setFlags()} on the {@link Intent} |
| * to set temporary access permissions, the same permissions are applied to all of the content |
| * URIs. |
| * </p> |
| * <p class="note"> |
| * <strong>Note:</strong> The {@link Intent#setClipData(ClipData) Intent.setClipData()} method is |
| * only available in platform version 16 (Android 4.1) and later. If you want to maintain |
| * compatibility with previous versions, you should send one content URI at a time in the |
| * {@link Intent}. Set the action to {@link Intent#ACTION_SEND} and put the URI in data by calling |
| * {@link Intent#setData setData()}. |
| * </p> |
| * <h3 id="">More Information</h3> |
| * <p> |
| * To learn more about FileProvider, see the Android training class |
| * <a href="{@docRoot}training/secure-file-sharing/index.html">Sharing Files Securely with URIs</a>. |
| * </p> |
| */ |
| public class FileProvider extends ContentProvider { |
| private static final String[] COLUMNS = { |
| OpenableColumns.DISPLAY_NAME, OpenableColumns.SIZE }; |
| |
| private static final String |
| META_DATA_FILE_PROVIDER_PATHS = "android.support.FILE_PROVIDER_PATHS"; |
| |
| private static final String TAG_ROOT_PATH = "root-path"; |
| private static final String TAG_FILES_PATH = "files-path"; |
| private static final String TAG_CACHE_PATH = "cache-path"; |
| private static final String TAG_EXTERNAL = "external-path"; |
| private static final String TAG_EXTERNAL_FILES = "external-files-path"; |
| private static final String TAG_EXTERNAL_CACHE = "external-cache-path"; |
| |
| private static final String ATTR_NAME = "name"; |
| private static final String ATTR_PATH = "path"; |
| |
| private static final File DEVICE_ROOT = new File("/"); |
| |
| // @GuardedBy("sCache") |
| private static HashMap<String, PathStrategy> sCache = new HashMap<String, PathStrategy>(); |
| |
| private PathStrategy mStrategy; |
| |
| /** |
| * The default FileProvider implementation does not need to be initialized. If you want to |
| * override this method, you must provide your own subclass of FileProvider. |
| */ |
| @Override |
| public boolean onCreate() { |
| return true; |
| } |
| |
| /** |
| * After the FileProvider is instantiated, this method is called to provide the system with |
| * information about the provider. |
| * |
| * @param context A {@link Context} for the current component. |
| * @param info A {@link ProviderInfo} for the new provider. |
| */ |
| @Override |
| public void attachInfo(Context context, ProviderInfo info) { |
| super.attachInfo(context, info); |
| |
| // Sanity check our security |
| if (info.exported) { |
| throw new SecurityException("Provider must not be exported"); |
| } |
| if (!info.grantUriPermissions) { |
| throw new SecurityException("Provider must grant uri permissions"); |
| } |
| |
| mStrategy = getPathStrategy(context, info.authority); |
| } |
| |
| /** |
| * Return a content URI for a given {@link File}. Specific temporary |
| * permissions for the content URI can be set with |
| * {@link Context#grantUriPermission(String, Uri, int)}, or added |
| * to an {@link Intent} by calling {@link Intent#setData(Uri) setData()} and then |
| * {@link Intent#setFlags(int) setFlags()}; in both cases, the applicable flags are |
| * {@link Intent#FLAG_GRANT_READ_URI_PERMISSION} and |
| * {@link Intent#FLAG_GRANT_WRITE_URI_PERMISSION}. A FileProvider can only return a |
| * <code>content</code> {@link Uri} for file paths defined in their <code><paths></code> |
| * meta-data element. See the Class Overview for more information. |
| * |
| * @param context A {@link Context} for the current component. |
| * @param authority The authority of a {@link FileProvider} defined in a |
| * {@code <provider>} element in your app's manifest. |
| * @param file A {@link File} pointing to the filename for which you want a |
| * <code>content</code> {@link Uri}. |
| * @return A content URI for the file. |
| * @throws IllegalArgumentException When the given {@link File} is outside |
| * the paths supported by the provider. |
| */ |
| public static Uri getUriForFile(Context context, String authority, File file) { |
| final PathStrategy strategy = getPathStrategy(context, authority); |
| return strategy.getUriForFile(file); |
| } |
| |
| /** |
| * Use a content URI returned by |
| * {@link #getUriForFile(Context, String, File) getUriForFile()} to get information about a file |
| * managed by the FileProvider. |
| * FileProvider reports the column names defined in {@link android.provider.OpenableColumns}: |
| * <ul> |
| * <li>{@link android.provider.OpenableColumns#DISPLAY_NAME}</li> |
| * <li>{@link android.provider.OpenableColumns#SIZE}</li> |
| * </ul> |
| * For more information, see |
| * {@link ContentProvider#query(Uri, String[], String, String[], String) |
| * ContentProvider.query()}. |
| * |
| * @param uri A content URI returned by {@link #getUriForFile}. |
| * @param projection The list of columns to put into the {@link Cursor}. If null all columns are |
| * included. |
| * @param selection Selection criteria to apply. If null then all data that matches the content |
| * URI is returned. |
| * @param selectionArgs An array of {@link java.lang.String}, containing arguments to bind to |
| * the <i>selection</i> parameter. The <i>query</i> method scans <i>selection</i> from left to |
| * right and iterates through <i>selectionArgs</i>, replacing the current "?" character in |
| * <i>selection</i> with the value at the current position in <i>selectionArgs</i>. The |
| * values are bound to <i>selection</i> as {@link java.lang.String} values. |
| * @param sortOrder A {@link java.lang.String} containing the column name(s) on which to sort |
| * the resulting {@link Cursor}. |
| * @return A {@link Cursor} containing the results of the query. |
| * |
| */ |
| @Override |
| public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, |
| String sortOrder) { |
| // ContentProvider has already checked granted permissions |
| final File file = mStrategy.getFileForUri(uri); |
| |
| if (projection == null) { |
| projection = COLUMNS; |
| } |
| |
| String[] cols = new String[projection.length]; |
| Object[] values = new Object[projection.length]; |
| int i = 0; |
| for (String col : projection) { |
| if (OpenableColumns.DISPLAY_NAME.equals(col)) { |
| cols[i] = OpenableColumns.DISPLAY_NAME; |
| values[i++] = file.getName(); |
| } else if (OpenableColumns.SIZE.equals(col)) { |
| cols[i] = OpenableColumns.SIZE; |
| values[i++] = file.length(); |
| } |
| } |
| |
| cols = copyOf(cols, i); |
| values = copyOf(values, i); |
| |
| final MatrixCursor cursor = new MatrixCursor(cols, 1); |
| cursor.addRow(values); |
| return cursor; |
| } |
| |
| /** |
| * Returns the MIME type of a content URI returned by |
| * {@link #getUriForFile(Context, String, File) getUriForFile()}. |
| * |
| * @param uri A content URI returned by |
| * {@link #getUriForFile(Context, String, File) getUriForFile()}. |
| * @return If the associated file has an extension, the MIME type associated with that |
| * extension; otherwise <code>application/octet-stream</code>. |
| */ |
| @Override |
| public String getType(Uri uri) { |
| // ContentProvider has already checked granted permissions |
| final File file = mStrategy.getFileForUri(uri); |
| |
| final int lastDot = file.getName().lastIndexOf('.'); |
| if (lastDot >= 0) { |
| final String extension = file.getName().substring(lastDot + 1); |
| final String mime = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension); |
| if (mime != null) { |
| return mime; |
| } |
| } |
| |
| return "application/octet-stream"; |
| } |
| |
| /** |
| * By default, this method throws an {@link java.lang.UnsupportedOperationException}. You must |
| * subclass FileProvider if you want to provide different functionality. |
| */ |
| @Override |
| public Uri insert(Uri uri, ContentValues values) { |
| throw new UnsupportedOperationException("No external inserts"); |
| } |
| |
| /** |
| * By default, this method throws an {@link java.lang.UnsupportedOperationException}. You must |
| * subclass FileProvider if you want to provide different functionality. |
| */ |
| @Override |
| public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) { |
| throw new UnsupportedOperationException("No external updates"); |
| } |
| |
| /** |
| * Deletes the file associated with the specified content URI, as |
| * returned by {@link #getUriForFile(Context, String, File) getUriForFile()}. Notice that this |
| * method does <b>not</b> throw an {@link java.io.IOException}; you must check its return value. |
| * |
| * @param uri A content URI for a file, as returned by |
| * {@link #getUriForFile(Context, String, File) getUriForFile()}. |
| * @param selection Ignored. Set to {@code null}. |
| * @param selectionArgs Ignored. Set to {@code null}. |
| * @return 1 if the delete succeeds; otherwise, 0. |
| */ |
| @Override |
| public int delete(Uri uri, String selection, String[] selectionArgs) { |
| // ContentProvider has already checked granted permissions |
| final File file = mStrategy.getFileForUri(uri); |
| return file.delete() ? 1 : 0; |
| } |
| |
| /** |
| * By default, FileProvider automatically returns the |
| * {@link ParcelFileDescriptor} for a file associated with a <code>content://</code> |
| * {@link Uri}. To get the {@link ParcelFileDescriptor}, call |
| * {@link android.content.ContentResolver#openFileDescriptor(Uri, String) |
| * ContentResolver.openFileDescriptor}. |
| * |
| * To override this method, you must provide your own subclass of FileProvider. |
| * |
| * @param uri A content URI associated with a file, as returned by |
| * {@link #getUriForFile(Context, String, File) getUriForFile()}. |
| * @param mode Access mode for the file. May be "r" for read-only access, "rw" for read and |
| * write access, or "rwt" for read and write access that truncates any existing file. |
| * @return A new {@link ParcelFileDescriptor} with which you can access the file. |
| */ |
| @Override |
| public ParcelFileDescriptor openFile(Uri uri, String mode) throws FileNotFoundException { |
| // ContentProvider has already checked granted permissions |
| final File file = mStrategy.getFileForUri(uri); |
| final int fileMode = modeToMode(mode); |
| return ParcelFileDescriptor.open(file, fileMode); |
| } |
| |
| /** |
| * Return {@link PathStrategy} for given authority, either by parsing or |
| * returning from cache. |
| */ |
| private static PathStrategy getPathStrategy(Context context, String authority) { |
| PathStrategy strat; |
| synchronized (sCache) { |
| strat = sCache.get(authority); |
| if (strat == null) { |
| try { |
| strat = parsePathStrategy(context, authority); |
| } catch (IOException e) { |
| throw new IllegalArgumentException( |
| "Failed to parse " + META_DATA_FILE_PROVIDER_PATHS + " meta-data", e); |
| } catch (XmlPullParserException e) { |
| throw new IllegalArgumentException( |
| "Failed to parse " + META_DATA_FILE_PROVIDER_PATHS + " meta-data", e); |
| } |
| sCache.put(authority, strat); |
| } |
| } |
| return strat; |
| } |
| |
| /** |
| * Parse and return {@link PathStrategy} for given authority as defined in |
| * {@link #META_DATA_FILE_PROVIDER_PATHS} {@code <meta-data>}. |
| * |
| * @see #getPathStrategy(Context, String) |
| */ |
| private static PathStrategy parsePathStrategy(Context context, String authority) |
| throws IOException, XmlPullParserException { |
| final SimplePathStrategy strat = new SimplePathStrategy(authority); |
| |
| final ProviderInfo info = context.getPackageManager() |
| .resolveContentProvider(authority, PackageManager.GET_META_DATA); |
| final XmlResourceParser in = info.loadXmlMetaData( |
| context.getPackageManager(), META_DATA_FILE_PROVIDER_PATHS); |
| if (in == null) { |
| throw new IllegalArgumentException( |
| "Missing " + META_DATA_FILE_PROVIDER_PATHS + " meta-data"); |
| } |
| |
| int type; |
| while ((type = in.next()) != END_DOCUMENT) { |
| if (type == START_TAG) { |
| final String tag = in.getName(); |
| |
| final String name = in.getAttributeValue(null, ATTR_NAME); |
| String path = in.getAttributeValue(null, ATTR_PATH); |
| |
| File target = null; |
| if (TAG_ROOT_PATH.equals(tag)) { |
| target = DEVICE_ROOT; |
| } else if (TAG_FILES_PATH.equals(tag)) { |
| target = context.getFilesDir(); |
| } else if (TAG_CACHE_PATH.equals(tag)) { |
| target = context.getCacheDir(); |
| } else if (TAG_EXTERNAL.equals(tag)) { |
| target = Environment.getExternalStorageDirectory(); |
| } else if (TAG_EXTERNAL_FILES.equals(tag)) { |
| File[] externalFilesDirs = ContextCompat.getExternalFilesDirs(context, null); |
| if (externalFilesDirs.length > 0) { |
| target = externalFilesDirs[0]; |
| } |
| } else if (TAG_EXTERNAL_CACHE.equals(tag)) { |
| File[] externalCacheDirs = ContextCompat.getExternalCacheDirs(context); |
| if (externalCacheDirs.length > 0) { |
| target = externalCacheDirs[0]; |
| } |
| } |
| |
| if (target != null) { |
| strat.addRoot(name, buildPath(target, path)); |
| } |
| } |
| } |
| |
| return strat; |
| } |
| |
| /** |
| * Strategy for mapping between {@link File} and {@link Uri}. |
| * <p> |
| * Strategies must be symmetric so that mapping a {@link File} to a |
| * {@link Uri} and then back to a {@link File} points at the original |
| * target. |
| * <p> |
| * Strategies must remain consistent across app launches, and not rely on |
| * dynamic state. This ensures that any generated {@link Uri} can still be |
| * resolved if your process is killed and later restarted. |
| * |
| * @see SimplePathStrategy |
| */ |
| interface PathStrategy { |
| /** |
| * Return a {@link Uri} that represents the given {@link File}. |
| */ |
| public Uri getUriForFile(File file); |
| |
| /** |
| * Return a {@link File} that represents the given {@link Uri}. |
| */ |
| public File getFileForUri(Uri uri); |
| } |
| |
| /** |
| * Strategy that provides access to files living under a narrow whitelist of |
| * filesystem roots. It will throw {@link SecurityException} if callers try |
| * accessing files outside the configured roots. |
| * <p> |
| * For example, if configured with |
| * {@code addRoot("myfiles", context.getFilesDir())}, then |
| * {@code context.getFileStreamPath("foo.txt")} would map to |
| * {@code content://myauthority/myfiles/foo.txt}. |
| */ |
| static class SimplePathStrategy implements PathStrategy { |
| private final String mAuthority; |
| private final HashMap<String, File> mRoots = new HashMap<String, File>(); |
| |
| public SimplePathStrategy(String authority) { |
| mAuthority = authority; |
| } |
| |
| /** |
| * Add a mapping from a name to a filesystem root. The provider only offers |
| * access to files that live under configured roots. |
| */ |
| public void addRoot(String name, File root) { |
| if (TextUtils.isEmpty(name)) { |
| throw new IllegalArgumentException("Name must not be empty"); |
| } |
| |
| try { |
| // Resolve to canonical path to keep path checking fast |
| root = root.getCanonicalFile(); |
| } catch (IOException e) { |
| throw new IllegalArgumentException( |
| "Failed to resolve canonical path for " + root, e); |
| } |
| |
| mRoots.put(name, root); |
| } |
| |
| @Override |
| public Uri getUriForFile(File file) { |
| String path; |
| try { |
| path = file.getCanonicalPath(); |
| } catch (IOException e) { |
| throw new IllegalArgumentException("Failed to resolve canonical path for " + file); |
| } |
| |
| // Find the most-specific root path |
| Map.Entry<String, File> mostSpecific = null; |
| for (Map.Entry<String, File> root : mRoots.entrySet()) { |
| final String rootPath = root.getValue().getPath(); |
| if (path.startsWith(rootPath) && (mostSpecific == null |
| || rootPath.length() > mostSpecific.getValue().getPath().length())) { |
| mostSpecific = root; |
| } |
| } |
| |
| if (mostSpecific == null) { |
| throw new IllegalArgumentException( |
| "Failed to find configured root that contains " + path); |
| } |
| |
| // Start at first char of path under root |
| final String rootPath = mostSpecific.getValue().getPath(); |
| if (rootPath.endsWith("/")) { |
| path = path.substring(rootPath.length()); |
| } else { |
| path = path.substring(rootPath.length() + 1); |
| } |
| |
| // Encode the tag and path separately |
| path = Uri.encode(mostSpecific.getKey()) + '/' + Uri.encode(path, "/"); |
| return new Uri.Builder().scheme("content") |
| .authority(mAuthority).encodedPath(path).build(); |
| } |
| |
| @Override |
| public File getFileForUri(Uri uri) { |
| String path = uri.getEncodedPath(); |
| |
| final int splitIndex = path.indexOf('/', 1); |
| final String tag = Uri.decode(path.substring(1, splitIndex)); |
| path = Uri.decode(path.substring(splitIndex + 1)); |
| |
| final File root = mRoots.get(tag); |
| if (root == null) { |
| throw new IllegalArgumentException("Unable to find configured root for " + uri); |
| } |
| |
| File file = new File(root, path); |
| try { |
| file = file.getCanonicalFile(); |
| } catch (IOException e) { |
| throw new IllegalArgumentException("Failed to resolve canonical path for " + file); |
| } |
| |
| if (!file.getPath().startsWith(root.getPath())) { |
| throw new SecurityException("Resolved path jumped beyond configured root"); |
| } |
| |
| return file; |
| } |
| } |
| |
| /** |
| * Copied from ContentResolver.java |
| */ |
| private static int modeToMode(String mode) { |
| int modeBits; |
| if ("r".equals(mode)) { |
| modeBits = ParcelFileDescriptor.MODE_READ_ONLY; |
| } else if ("w".equals(mode) || "wt".equals(mode)) { |
| modeBits = ParcelFileDescriptor.MODE_WRITE_ONLY |
| | ParcelFileDescriptor.MODE_CREATE |
| | ParcelFileDescriptor.MODE_TRUNCATE; |
| } else if ("wa".equals(mode)) { |
| modeBits = ParcelFileDescriptor.MODE_WRITE_ONLY |
| | ParcelFileDescriptor.MODE_CREATE |
| | ParcelFileDescriptor.MODE_APPEND; |
| } else if ("rw".equals(mode)) { |
| modeBits = ParcelFileDescriptor.MODE_READ_WRITE |
| | ParcelFileDescriptor.MODE_CREATE; |
| } else if ("rwt".equals(mode)) { |
| modeBits = ParcelFileDescriptor.MODE_READ_WRITE |
| | ParcelFileDescriptor.MODE_CREATE |
| | ParcelFileDescriptor.MODE_TRUNCATE; |
| } else { |
| throw new IllegalArgumentException("Invalid mode: " + mode); |
| } |
| return modeBits; |
| } |
| |
| private static File buildPath(File base, String... segments) { |
| File cur = base; |
| for (String segment : segments) { |
| if (segment != null) { |
| cur = new File(cur, segment); |
| } |
| } |
| return cur; |
| } |
| |
| private static String[] copyOf(String[] original, int newLength) { |
| final String[] result = new String[newLength]; |
| System.arraycopy(original, 0, result, 0, newLength); |
| return result; |
| } |
| |
| private static Object[] copyOf(Object[] original, int newLength) { |
| final Object[] result = new Object[newLength]; |
| System.arraycopy(original, 0, result, 0, newLength); |
| return result; |
| } |
| } |
