<manifest> * ... * <application> * ... * <provider * android:name="com.example.MyCloudProvider" * android:authorities="com.example.mycloudprovider" * android:exported="true" * android:grantUriPermissions="true" * android:permission="android.permission.MANAGE_DOCUMENTS" * android:enabled="@bool/isAtLeastKitKat"> * <intent-filter> * <action android:name="android.content.action.DOCUMENTS_PROVIDER" /> * </intent-filter> * </provider> * ... * </application> *</manifest>*
* When defining your provider, you must protect it with * {@link android.Manifest.permission#MANAGE_DOCUMENTS}, which is a permission * only the system can obtain. Applications cannot use a documents provider * directly; they must go through {@link Intent#ACTION_OPEN_DOCUMENT} or * {@link Intent#ACTION_CREATE_DOCUMENT} which requires a user to actively * navigate and select documents. When a user selects documents through that UI, * the system issues narrow URI permission grants to the requesting application. *
** A document can be either an openable stream (with a specific MIME type), or a * directory containing additional documents (with the * {@link Document#MIME_TYPE_DIR} MIME type). Each directory represents the top * of a subtree containing zero or more documents, which can recursively contain * even more documents and directories. *
** Each document can have different capabilities, as described by * {@link Document#COLUMN_FLAGS}. For example, if a document can be represented * as a thumbnail, your provider can set * {@link Document#FLAG_SUPPORTS_THUMBNAIL} and implement * {@link #openDocumentThumbnail(String, Point, CancellationSignal)} to return * that thumbnail. *
** Each document under a provider is uniquely referenced by its * {@link Document#COLUMN_DOCUMENT_ID}, which must not change once returned. A * single document can be included in multiple directories when responding to * {@link #queryChildDocuments(String, String[], String)}. For example, a * provider might surface a single photo in multiple locations: once in a * directory of geographic locations, and again in a directory of dates. *
** All documents are surfaced through one or more "roots." Each root represents * the top of a document tree that a user can navigate. For example, a root * could represent an account or a physical storage device. Similar to * documents, each root can have capabilities expressed through * {@link Root#COLUMN_FLAGS}. *
* * @see Intent#ACTION_OPEN_DOCUMENT * @see Intent#ACTION_OPEN_DOCUMENT_TREE * @see Intent#ACTION_CREATE_DOCUMENT */ public abstract class DocumentsProvider extends ContentProvider { private static final String TAG = "DocumentsProvider"; private static final int MATCH_ROOTS = 1; private static final int MATCH_ROOT = 2; private static final int MATCH_RECENT = 3; private static final int MATCH_SEARCH = 4; private static final int MATCH_DOCUMENT = 5; private static final int MATCH_CHILDREN = 6; private static final int MATCH_DOCUMENT_TREE = 7; private static final int MATCH_CHILDREN_TREE = 8; private String mAuthority; private UriMatcher mMatcher; /** * Implementation is provided by the parent class. */ @Override public void attachInfo(Context context, ProviderInfo info) { mAuthority = info.authority; mMatcher = new UriMatcher(UriMatcher.NO_MATCH); mMatcher.addURI(mAuthority, "root", MATCH_ROOTS); mMatcher.addURI(mAuthority, "root/*", MATCH_ROOT); mMatcher.addURI(mAuthority, "root/*/recent", MATCH_RECENT); mMatcher.addURI(mAuthority, "root/*/search", MATCH_SEARCH); mMatcher.addURI(mAuthority, "document/*", MATCH_DOCUMENT); mMatcher.addURI(mAuthority, "document/*/children", MATCH_CHILDREN); mMatcher.addURI(mAuthority, "tree/*/document/*", MATCH_DOCUMENT_TREE); mMatcher.addURI(mAuthority, "tree/*/document/*/children", MATCH_CHILDREN_TREE); // Sanity check our setup if (!info.exported) { throw new SecurityException("Provider must be exported"); } if (!info.grantUriPermissions) { throw new SecurityException("Provider must grantUriPermissions"); } if (!android.Manifest.permission.MANAGE_DOCUMENTS.equals(info.readPermission) || !android.Manifest.permission.MANAGE_DOCUMENTS.equals(info.writePermission)) { throw new SecurityException("Provider must be protected by MANAGE_DOCUMENTS"); } super.attachInfo(context, info); } /** * Test if a document is descendant (child, grandchild, etc) from the given * parent. For example, providers must implement this to support * {@link Intent#ACTION_OPEN_DOCUMENT_TREE}. You should avoid making network * requests to keep this request fast. * * @param parentDocumentId parent to verify against. * @param documentId child to verify. * @return if given document is a descendant of the given parent. * @see DocumentsContract.Root#FLAG_SUPPORTS_IS_CHILD */ public boolean isChildDocument(String parentDocumentId, String documentId) { return false; } /** {@hide} */ private void enforceTree(Uri documentUri) { if (isTreeUri(documentUri)) { final String parent = getTreeDocumentId(documentUri); final String child = getDocumentId(documentUri); if (Objects.equals(parent, child)) { return; } if (!isChildDocument(parent, child)) { throw new SecurityException( "Document " + child + " is not a descendant of " + parent); } } } /** * Create a new document and return its newly generated * {@link Document#COLUMN_DOCUMENT_ID}. You must allocate a new * {@link Document#COLUMN_DOCUMENT_ID} to represent the document, which must * not change once returned. * * @param parentDocumentId the parent directory to create the new document * under. * @param mimeType the concrete MIME type associated with the new document. * If the MIME type is not supported, the provider must throw. * @param displayName the display name of the new document. The provider may * alter this name to meet any internal constraints, such as * avoiding conflicting names. */ @SuppressWarnings("unused") public String createDocument(String parentDocumentId, String mimeType, String displayName) throws FileNotFoundException { throw new UnsupportedOperationException("Create not supported"); } /** * Rename an existing document. ** If a different {@link Document#COLUMN_DOCUMENT_ID} must be used to * represent the renamed document, generate and return it. Any outstanding * URI permission grants will be updated to point at the new document. If * the original {@link Document#COLUMN_DOCUMENT_ID} is still valid after the * rename, return {@code null}. * * @param documentId the document to rename. * @param displayName the updated display name of the document. The provider * may alter this name to meet any internal constraints, such as * avoiding conflicting names. */ @SuppressWarnings("unused") public String renameDocument(String documentId, String displayName) throws FileNotFoundException { throw new UnsupportedOperationException("Rename not supported"); } /** * Delete the requested document. *
* Upon returning, any URI permission grants for the given document will be * revoked. If additional documents were deleted as a side effect of this * call (such as documents inside a directory) the implementor is * responsible for revoking those permissions using * {@link #revokeDocumentPermission(String)}. * * @param documentId the document to delete. */ @SuppressWarnings("unused") public void deleteDocument(String documentId) throws FileNotFoundException { throw new UnsupportedOperationException("Delete not supported"); } /** * Return all roots currently provided. To display to users, you must define * at least one root. You should avoid making network requests to keep this * request fast. *
* Each root is defined by the metadata columns described in {@link Root}, * including {@link Root#COLUMN_DOCUMENT_ID} which points to a directory * representing a tree of documents to display under that root. *
* If this set of roots changes, you must call {@link ContentResolver#notifyChange(Uri, * android.database.ContentObserver, boolean)} with * {@link DocumentsContract#buildRootsUri(String)} to notify the system. * * @param projection list of {@link Root} columns to put into the cursor. If * {@code null} all supported columns should be included. */ public abstract Cursor queryRoots(String[] projection) throws FileNotFoundException; /** * Return recently modified documents under the requested root. This will * only be called for roots that advertise * {@link Root#FLAG_SUPPORTS_RECENTS}. The returned documents should be * sorted by {@link Document#COLUMN_LAST_MODIFIED} in descending order, and * limited to only return the 64 most recently modified documents. *
* Recent documents do not support change notifications. * * @param projection list of {@link Document} columns to put into the * cursor. If {@code null} all supported columns should be * included. * @see DocumentsContract#EXTRA_LOADING */ @SuppressWarnings("unused") public Cursor queryRecentDocuments(String rootId, String[] projection) throws FileNotFoundException { throw new UnsupportedOperationException("Recent not supported"); } /** * Return metadata for the single requested document. You should avoid * making network requests to keep this request fast. * * @param documentId the document to return. * @param projection list of {@link Document} columns to put into the * cursor. If {@code null} all supported columns should be * included. */ public abstract Cursor queryDocument(String documentId, String[] projection) throws FileNotFoundException; /** * Return the children documents contained in the requested directory. This * must only return immediate descendants, as additional queries will be * issued to recursively explore the tree. *
* If your provider is cloud-based, and you have some data cached or pinned * locally, you may return the local data immediately, setting * {@link DocumentsContract#EXTRA_LOADING} on the Cursor to indicate that * you are still fetching additional data. Then, when the network data is * available, you can send a change notification to trigger a requery and * return the complete contents. To return a Cursor with extras, you need to * extend and override {@link Cursor#getExtras()}. *
* To support change notifications, you must * {@link Cursor#setNotificationUri(ContentResolver, Uri)} with a relevant * Uri, such as * {@link DocumentsContract#buildChildDocumentsUri(String, String)}. Then * you can call {@link ContentResolver#notifyChange(Uri, * android.database.ContentObserver, boolean)} with that Uri to send change * notifications. * * @param parentDocumentId the directory to return children for. * @param projection list of {@link Document} columns to put into the * cursor. If {@code null} all supported columns should be * included. * @param sortOrder how to order the rows, formatted as an SQL * {@code ORDER BY} clause (excluding the ORDER BY itself). * Passing {@code null} will use the default sort order, which * may be unordered. This ordering is a hint that can be used to * prioritize how data is fetched from the network, but UI may * always enforce a specific ordering. * @see DocumentsContract#EXTRA_LOADING * @see DocumentsContract#EXTRA_INFO * @see DocumentsContract#EXTRA_ERROR */ public abstract Cursor queryChildDocuments( String parentDocumentId, String[] projection, String sortOrder) throws FileNotFoundException; /** {@hide} */ @SuppressWarnings("unused") public Cursor queryChildDocumentsForManage( String parentDocumentId, String[] projection, String sortOrder) throws FileNotFoundException { throw new UnsupportedOperationException("Manage not supported"); } /** * Return documents that that match the given query under the requested * root. The returned documents should be sorted by relevance in descending * order. How documents are matched against the query string is an * implementation detail left to each provider, but it's suggested that at * least {@link Document#COLUMN_DISPLAY_NAME} be matched in a * case-insensitive fashion. *
* Only documents may be returned; directories are not supported in search * results. *
* If your provider is cloud-based, and you have some data cached or pinned * locally, you may return the local data immediately, setting * {@link DocumentsContract#EXTRA_LOADING} on the Cursor to indicate that * you are still fetching additional data. Then, when the network data is * available, you can send a change notification to trigger a requery and * return the complete contents. *
* To support change notifications, you must * {@link Cursor#setNotificationUri(ContentResolver, Uri)} with a relevant * Uri, such as {@link DocumentsContract#buildSearchDocumentsUri(String, * String, String)}. Then you can call {@link ContentResolver#notifyChange(Uri, * android.database.ContentObserver, boolean)} with that Uri to send change * notifications. * * @param rootId the root to search under. * @param query string to match documents against. * @param projection list of {@link Document} columns to put into the * cursor. If {@code null} all supported columns should be * included. * @see DocumentsContract#EXTRA_LOADING * @see DocumentsContract#EXTRA_INFO * @see DocumentsContract#EXTRA_ERROR */ @SuppressWarnings("unused") public Cursor querySearchDocuments(String rootId, String query, String[] projection) throws FileNotFoundException { throw new UnsupportedOperationException("Search not supported"); } /** * Return concrete MIME type of the requested document. Must match the value * of {@link Document#COLUMN_MIME_TYPE} for this document. The default * implementation queries {@link #queryDocument(String, String[])}, so * providers may choose to override this as an optimization. */ public String getDocumentType(String documentId) throws FileNotFoundException { final Cursor cursor = queryDocument(documentId, null); try { if (cursor.moveToFirst()) { return cursor.getString(cursor.getColumnIndexOrThrow(Document.COLUMN_MIME_TYPE)); } else { return null; } } finally { IoUtils.closeQuietly(cursor); } } /** * Open and return the requested document. *
* Your provider should return a reliable {@link ParcelFileDescriptor} to * detect when the remote caller has finished reading or writing the * document. You may return a pipe or socket pair if the mode is exclusively * "r" or "w", but complex modes like "rw" imply a normal file on disk that * supports seeking. *
* If you block while downloading content, you should periodically check * {@link CancellationSignal#isCanceled()} to abort abandoned open requests. * * @param documentId the document to return. * @param mode the mode to open with, such as 'r', 'w', or 'rw'. * @param signal used by the caller to signal if the request should be * cancelled. May be null. * @see ParcelFileDescriptor#open(java.io.File, int, android.os.Handler, * OnCloseListener) * @see ParcelFileDescriptor#createReliablePipe() * @see ParcelFileDescriptor#createReliableSocketPair() * @see ParcelFileDescriptor#parseMode(String) */ public abstract ParcelFileDescriptor openDocument( String documentId, String mode, CancellationSignal signal) throws FileNotFoundException; /** * Open and return a thumbnail of the requested document. *
* A provider should return a thumbnail closely matching the hinted size, * attempting to serve from a local cache if possible. A provider should * never return images more than double the hinted size. *
* If you perform expensive operations to download or generate a thumbnail, * you should periodically check {@link CancellationSignal#isCanceled()} to * abort abandoned thumbnail requests. * * @param documentId the document to return. * @param sizeHint hint of the optimal thumbnail dimensions. * @param signal used by the caller to signal if the request should be * cancelled. May be null. * @see Document#FLAG_SUPPORTS_THUMBNAIL */ @SuppressWarnings("unused") public AssetFileDescriptor openDocumentThumbnail( String documentId, Point sizeHint, CancellationSignal signal) throws FileNotFoundException { throw new UnsupportedOperationException("Thumbnails not supported"); } /** * Implementation is provided by the parent class. Cannot be overriden. * * @see #queryRoots(String[]) * @see #queryRecentDocuments(String, String[]) * @see #queryDocument(String, String[]) * @see #queryChildDocuments(String, String[], String) * @see #querySearchDocuments(String, String, String[]) */ @Override public final Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) { try { switch (mMatcher.match(uri)) { case MATCH_ROOTS: return queryRoots(projection); case MATCH_RECENT: return queryRecentDocuments(getRootId(uri), projection); case MATCH_SEARCH: return querySearchDocuments( getRootId(uri), getSearchDocumentsQuery(uri), projection); case MATCH_DOCUMENT: case MATCH_DOCUMENT_TREE: enforceTree(uri); return queryDocument(getDocumentId(uri), projection); case MATCH_CHILDREN: case MATCH_CHILDREN_TREE: enforceTree(uri); if (DocumentsContract.isManageMode(uri)) { return queryChildDocumentsForManage( getDocumentId(uri), projection, sortOrder); } else { return queryChildDocuments(getDocumentId(uri), projection, sortOrder); } default: throw new UnsupportedOperationException("Unsupported Uri " + uri); } } catch (FileNotFoundException e) { Log.w(TAG, "Failed during query", e); return null; } } /** * Implementation is provided by the parent class. Cannot be overriden. * * @see #getDocumentType(String) */ @Override public final String getType(Uri uri) { try { switch (mMatcher.match(uri)) { case MATCH_ROOT: return DocumentsContract.Root.MIME_TYPE_ITEM; case MATCH_DOCUMENT: case MATCH_DOCUMENT_TREE: enforceTree(uri); return getDocumentType(getDocumentId(uri)); default: return null; } } catch (FileNotFoundException e) { Log.w(TAG, "Failed during getType", e); return null; } } /** * Implementation is provided by the parent class. Can be overridden to * provide additional functionality, but subclasses must always * call the superclass. If the superclass returns {@code null}, the subclass * may implement custom behavior. *
* This is typically used to resolve a subtree URI into a concrete document * reference, issuing a narrower single-document URI permission grant along * the way. * * @see DocumentsContract#buildDocumentUriUsingTree(Uri, String) */ @Override public Uri canonicalize(Uri uri) { final Context context = getContext(); switch (mMatcher.match(uri)) { case MATCH_DOCUMENT_TREE: enforceTree(uri); final Uri narrowUri = buildDocumentUri(uri.getAuthority(), getDocumentId(uri)); // Caller may only have prefix grant, so extend them a grant to // the narrow URI. final int modeFlags = getCallingOrSelfUriPermissionModeFlags(context, uri); context.grantUriPermission(getCallingPackage(), narrowUri, modeFlags); return narrowUri; } return null; } private static int getCallingOrSelfUriPermissionModeFlags(Context context, Uri uri) { // TODO: move this to a direct AMS call int modeFlags = 0; if (context.checkCallingOrSelfUriPermission(uri, Intent.FLAG_GRANT_READ_URI_PERMISSION) == PackageManager.PERMISSION_GRANTED) { modeFlags |= Intent.FLAG_GRANT_READ_URI_PERMISSION; } if (context.checkCallingOrSelfUriPermission(uri, Intent.FLAG_GRANT_WRITE_URI_PERMISSION) == PackageManager.PERMISSION_GRANTED) { modeFlags |= Intent.FLAG_GRANT_WRITE_URI_PERMISSION; } if (context.checkCallingOrSelfUriPermission(uri, Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_PERSISTABLE_URI_PERMISSION) == PackageManager.PERMISSION_GRANTED) { modeFlags |= Intent.FLAG_GRANT_PERSISTABLE_URI_PERMISSION; } return modeFlags; } /** * Implementation is provided by the parent class. Throws by default, and * cannot be overriden. * * @see #createDocument(String, String, String) */ @Override public final Uri insert(Uri uri, ContentValues values) { throw new UnsupportedOperationException("Insert not supported"); } /** * Implementation is provided by the parent class. Throws by default, and * cannot be overriden. * * @see #deleteDocument(String) */ @Override public final int delete(Uri uri, String selection, String[] selectionArgs) { throw new UnsupportedOperationException("Delete not supported"); } /** * Implementation is provided by the parent class. Throws by default, and * cannot be overriden. */ @Override public final int update( Uri uri, ContentValues values, String selection, String[] selectionArgs) { throw new UnsupportedOperationException("Update not supported"); } /** * Implementation is provided by the parent class. Can be overridden to * provide additional functionality, but subclasses must always * call the superclass. If the superclass returns {@code null}, the subclass * may implement custom behavior. */ @Override public Bundle call(String method, String arg, Bundle extras) { if (!method.startsWith("android:")) { // Ignore non-platform methods return super.call(method, arg, extras); } final Context context = getContext(); final Uri documentUri = extras.getParcelable(DocumentsContract.EXTRA_URI); final String authority = documentUri.getAuthority(); final String documentId = DocumentsContract.getDocumentId(documentUri); if (!mAuthority.equals(authority)) { throw new SecurityException( "Requested authority " + authority + " doesn't match provider " + mAuthority); } enforceTree(documentUri); final Bundle out = new Bundle(); try { if (METHOD_CREATE_DOCUMENT.equals(method)) { enforceWritePermissionInner(documentUri, null); final String mimeType = extras.getString(Document.COLUMN_MIME_TYPE); final String displayName = extras.getString(Document.COLUMN_DISPLAY_NAME); final String newDocumentId = createDocument(documentId, mimeType, displayName); // No need to issue new grants here, since caller either has // manage permission or a prefix grant. We might generate a // tree style URI if that's how they called us. final Uri newDocumentUri = buildDocumentUriMaybeUsingTree(documentUri, newDocumentId); out.putParcelable(DocumentsContract.EXTRA_URI, newDocumentUri); } else if (METHOD_RENAME_DOCUMENT.equals(method)) { enforceWritePermissionInner(documentUri, null); final String displayName = extras.getString(Document.COLUMN_DISPLAY_NAME); final String newDocumentId = renameDocument(documentId, displayName); if (newDocumentId != null) { final Uri newDocumentUri = buildDocumentUriMaybeUsingTree(documentUri, newDocumentId); // If caller came in with a narrow grant, issue them a // narrow grant for the newly renamed document. if (!isTreeUri(newDocumentUri)) { final int modeFlags = getCallingOrSelfUriPermissionModeFlags(context, documentUri); context.grantUriPermission(getCallingPackage(), newDocumentUri, modeFlags); } out.putParcelable(DocumentsContract.EXTRA_URI, newDocumentUri); // Original document no longer exists, clean up any grants revokeDocumentPermission(documentId); } } else if (METHOD_DELETE_DOCUMENT.equals(method)) { enforceWritePermissionInner(documentUri, null); deleteDocument(documentId); // Document no longer exists, clean up any grants revokeDocumentPermission(documentId); } else { throw new UnsupportedOperationException("Method not supported " + method); } } catch (FileNotFoundException e) { throw new IllegalStateException("Failed call " + method, e); } return out; } /** * Revoke any active permission grants for the given * {@link Document#COLUMN_DOCUMENT_ID}, usually called when a document * becomes invalid. Follows the same semantics as * {@link Context#revokeUriPermission(Uri, int)}. */ public final void revokeDocumentPermission(String documentId) { final Context context = getContext(); context.revokeUriPermission(buildDocumentUri(mAuthority, documentId), ~0); context.revokeUriPermission(buildTreeDocumentUri(mAuthority, documentId), ~0); } /** * Implementation is provided by the parent class. Cannot be overriden. * * @see #openDocument(String, String, CancellationSignal) */ @Override public final ParcelFileDescriptor openFile(Uri uri, String mode) throws FileNotFoundException { enforceTree(uri); return openDocument(getDocumentId(uri), mode, null); } /** * Implementation is provided by the parent class. Cannot be overriden. * * @see #openDocument(String, String, CancellationSignal) */ @Override public final ParcelFileDescriptor openFile(Uri uri, String mode, CancellationSignal signal) throws FileNotFoundException { enforceTree(uri); return openDocument(getDocumentId(uri), mode, signal); } /** * Implementation is provided by the parent class. Cannot be overriden. * * @see #openDocument(String, String, CancellationSignal) */ @Override @SuppressWarnings("resource") public final AssetFileDescriptor openAssetFile(Uri uri, String mode) throws FileNotFoundException { enforceTree(uri); final ParcelFileDescriptor fd = openDocument(getDocumentId(uri), mode, null); return fd != null ? new AssetFileDescriptor(fd, 0, -1) : null; } /** * Implementation is provided by the parent class. Cannot be overriden. * * @see #openDocument(String, String, CancellationSignal) */ @Override @SuppressWarnings("resource") public final AssetFileDescriptor openAssetFile(Uri uri, String mode, CancellationSignal signal) throws FileNotFoundException { enforceTree(uri); final ParcelFileDescriptor fd = openDocument(getDocumentId(uri), mode, signal); return fd != null ? new AssetFileDescriptor(fd, 0, -1) : null; } /** * Implementation is provided by the parent class. Cannot be overriden. * * @see #openDocumentThumbnail(String, Point, CancellationSignal) */ @Override public final AssetFileDescriptor openTypedAssetFile(Uri uri, String mimeTypeFilter, Bundle opts) throws FileNotFoundException { enforceTree(uri); if (opts != null && opts.containsKey(ContentResolver.EXTRA_SIZE)) { final Point sizeHint = opts.getParcelable(ContentResolver.EXTRA_SIZE); return openDocumentThumbnail(getDocumentId(uri), sizeHint, null); } else { return super.openTypedAssetFile(uri, mimeTypeFilter, opts); } } /** * Implementation is provided by the parent class. Cannot be overriden. * * @see #openDocumentThumbnail(String, Point, CancellationSignal) */ @Override public final AssetFileDescriptor openTypedAssetFile( Uri uri, String mimeTypeFilter, Bundle opts, CancellationSignal signal) throws FileNotFoundException { enforceTree(uri); if (opts != null && opts.containsKey(ContentResolver.EXTRA_SIZE)) { final Point sizeHint = opts.getParcelable(ContentResolver.EXTRA_SIZE); return openDocumentThumbnail(getDocumentId(uri), sizeHint, signal); } else { return super.openTypedAssetFile(uri, mimeTypeFilter, opts, signal); } } }