Java tutorial
/* * 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 utils.bobo.com.boboutils.App.appwidget; 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()}. * <dt> * <pre class="prettyprint"> *<external-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 path * {@link Context#getExternalFilesDir(String) Context.getExternalFilesDir()} returns the * <code>files/</code> subdirectory of this this root. * </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> * </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 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, 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 CustomViewFileProvider extends ContentProvider { public static final String AUTHORITIES = "utils.bobo.com.boboutils.CustomViewFileProvider"; 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 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 OpenableColumns}: * <ul> * <li>{@link OpenableColumns#DISPLAY_NAME}</li> * <li>{@link 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 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 String} values. * @param sortOrder A {@link 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 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 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 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 = buildPath(DEVICE_ROOT, path); } else if (TAG_FILES_PATH.equals(tag)) { target = buildPath(context.getFilesDir(), path); } else if (TAG_CACHE_PATH.equals(tag)) { target = buildPath(context.getCacheDir(), path); } else if (TAG_EXTERNAL.equals(tag)) { target = buildPath(Environment.getExternalStorageDirectory(), path); } if (target != null) { strat.addRoot(name, target); } } } 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; } }