Initial Contribution

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diff --git a/core/java/android/content/ContentProvider.java b/core/java/android/content/ContentProvider.java
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+/*
+ * Copyright (C) 2006 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.content;
+
+import android.content.pm.PackageManager;
+import android.content.pm.ProviderInfo;
+import android.content.res.Configuration;
+import android.database.Cursor;
+import android.database.CursorToBulkCursorAdaptor;
+import android.database.CursorWindow;
+import android.database.IBulkCursor;
+import android.database.IContentObserver;
+import android.database.SQLException;
+import android.net.Uri;
+import android.os.Binder;
+import android.os.ParcelFileDescriptor;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+
+/**
+ * Content providers are one of the primary building blocks of Android applications, providing
+ * content to applications. They encapsulate data and provide it to applications through the single
+ * {@link ContentResolver} interface. A content provider is only required if you need to share
+ * data between multiple applications. For example, the contacts data is used by multiple
+ * applications and must be stored in a content provider. If you don't need to share data amongst
+ * multiple applications you can use a database directly via
+ * {@link android.database.sqlite.SQLiteDatabase}.
+ *
+ * <p>See <a href="{@docRoot}devel/data/contentproviders.html">this page</a> for more information on
+ * content providers.</p>
+ *
+ * <p>When a request is made via
+ * a {@link ContentResolver} the system inspects the authority of the given URI and passes the
+ * request to the content provider registered with the authority. The content provider can interpret
+ * the rest of the URI however it wants. The {@link UriMatcher} class is helpful for parsing
+ * URIs.</p>
+ *
+ * <p>The primary methods that need to be implemented are:
+ * <ul>
+ *   <li>{@link #query} which returns data to the caller</li>
+ *   <li>{@link #insert} which inserts new data into the content provider</li>
+ *   <li>{@link #update} which updates existing data in the content provider</li>
+ *   <li>{@link #delete} which deletes data from the content provider</li>
+ *   <li>{@link #getType} which returns the MIME type of data in the content provider</li>
+ * </ul></p>
+ *
+ * <p>This class takes care of cross process calls so subclasses don't have to worry about which
+ * process a request is coming from.</p>
+ */
+public abstract class ContentProvider implements ComponentCallbacks {
+    private Context mContext = null;
+    private String mReadPermission;
+    private String mWritePermission;
+
+    private Transport mTransport = new Transport();
+
+    /**
+     * Given an IContentProvider, try to coerce it back to the real
+     * ContentProvider object if it is running in the local process.  This can
+     * be used if you know you are running in the same process as a provider,
+     * and want to get direct access to its implementation details.  Most
+     * clients should not nor have a reason to use it.
+     *
+     * @param abstractInterface The ContentProvider interface that is to be
+     *              coerced.
+     * @return If the IContentProvider is non-null and local, returns its actual
+     * ContentProvider instance.  Otherwise returns null.
+     * @hide
+     */
+    public static ContentProvider coerceToLocalContentProvider(
+            IContentProvider abstractInterface) {
+        if (abstractInterface instanceof Transport) {
+            return ((Transport)abstractInterface).getContentProvider();
+        }
+        return null;
+    }
+
+    /**
+     * Binder object that deals with remoting.
+     *
+     * @hide
+     */
+    class Transport extends ContentProviderNative {
+        ContentProvider getContentProvider() {
+            return ContentProvider.this;
+        }
+
+        /**
+         * Remote version of a query, which returns an IBulkCursor. The bulk
+         * cursor should be wrapped with BulkCursorToCursorAdaptor before use.
+         */
+        public IBulkCursor bulkQuery(Uri uri, String[] projection,
+                String selection, String[] selectionArgs, String sortOrder,
+                IContentObserver observer, CursorWindow window) {
+            checkReadPermission(uri);
+            Cursor cursor = ContentProvider.this.query(uri, projection,
+                    selection, selectionArgs, sortOrder);
+            if (cursor == null) {
+                return null;
+            }
+            String wperm = getWritePermission();
+            return new CursorToBulkCursorAdaptor(cursor, observer,
+                    ContentProvider.this.getClass().getName(),
+                    wperm == null ||
+                    getContext().checkCallingOrSelfPermission(getWritePermission())
+                            == PackageManager.PERMISSION_GRANTED,
+                    window);
+        }
+
+        public Cursor query(Uri uri, String[] projection,
+                String selection, String[] selectionArgs, String sortOrder) {
+            checkReadPermission(uri);
+            return ContentProvider.this.query(uri, projection, selection,
+                    selectionArgs, sortOrder);
+        }
+
+        public String getType(Uri uri) {
+            return ContentProvider.this.getType(uri);
+        }
+
+
+        public Uri insert(Uri uri, ContentValues initialValues) {
+            checkWritePermission(uri);
+            return ContentProvider.this.insert(uri, initialValues);
+        }
+
+        public int bulkInsert(Uri uri, ContentValues[] initialValues) {
+            checkWritePermission(uri);
+            return ContentProvider.this.bulkInsert(uri, initialValues);
+        }
+
+        public int delete(Uri uri, String selection, String[] selectionArgs) {
+            checkWritePermission(uri);
+            return ContentProvider.this.delete(uri, selection, selectionArgs);
+        }
+
+        public int update(Uri uri, ContentValues values, String selection,
+                String[] selectionArgs) {
+            checkWritePermission(uri);
+            return ContentProvider.this.update(uri, values, selection, selectionArgs);
+        }
+
+        public ParcelFileDescriptor openFile(Uri uri, String mode)
+                throws FileNotFoundException {
+            if (mode != null && mode.startsWith("rw")) checkWritePermission(uri);
+            else checkReadPermission(uri);
+            return ContentProvider.this.openFile(uri, mode);
+        }
+
+        public ISyncAdapter getSyncAdapter() {
+            checkWritePermission(null);
+            return ContentProvider.this.getSyncAdapter().getISyncAdapter();
+        }
+
+        private void checkReadPermission(Uri uri) {
+            final String rperm = getReadPermission();
+            final int pid = Binder.getCallingPid();
+            final int uid = Binder.getCallingUid();
+            if (getContext().checkUriPermission(uri, rperm, null, pid, uid,
+                    Intent.FLAG_GRANT_READ_URI_PERMISSION)
+                    == PackageManager.PERMISSION_GRANTED) {
+                return;
+            }
+            String msg = "Permission Denial: reading "
+                    + ContentProvider.this.getClass().getName()
+                    + " uri " + uri + " from pid=" + Binder.getCallingPid()
+                    + ", uid=" + Binder.getCallingUid()
+                    + " requires " + rperm;
+            throw new SecurityException(msg);
+        }
+
+        private void checkWritePermission(Uri uri) {
+            final String wperm = getWritePermission();
+            final int pid = Binder.getCallingPid();
+            final int uid = Binder.getCallingUid();
+            if (getContext().checkUriPermission(uri, null, wperm, pid, uid,
+                    Intent.FLAG_GRANT_WRITE_URI_PERMISSION)
+                    == PackageManager.PERMISSION_GRANTED) {
+                return;
+            }
+            String msg = "Permission Denial: writing "
+                    + ContentProvider.this.getClass().getName()
+                    + " uri " + uri + " from pid=" + Binder.getCallingPid()
+                    + ", uid=" + Binder.getCallingUid()
+                    + " requires " + wperm;
+            throw new SecurityException(msg);
+        }
+    }
+
+
+    /**
+     * Retrieve the Context this provider is running in.  Only available once
+     * onCreate(Map icicle) has been called -- this will be null in the
+     * constructor.
+     */
+    public final Context getContext() {
+        return mContext;
+    }
+
+    /**
+     * Change the permission required to read data from the content
+     * provider.  This is normally set for you from its manifest information
+     * when the provider is first created.
+     *
+     * @param permission Name of the permission required for read-only access.
+     */
+    protected final void setReadPermission(String permission) {
+        mReadPermission = permission;
+    }
+
+    /**
+     * Return the name of the permission required for read-only access to
+     * this content provider.  This method can be called from multiple
+     * threads, as described in the
+     * <a href="{@docRoot}intro/appmodel.html#Threads">Threading section of
+     * the Application Model overview</a>.
+     */
+    public final String getReadPermission() {
+        return mReadPermission;
+    }
+
+    /**
+     * Change the permission required to read and write data in the content
+     * provider.  This is normally set for you from its manifest information
+     * when the provider is first created.
+     *
+     * @param permission Name of the permission required for read/write access.
+     */
+    protected final void setWritePermission(String permission) {
+        mWritePermission = permission;
+    }
+
+    /**
+     * Return the name of the permission required for read/write access to
+     * this content provider.  This method can be called from multiple
+     * threads, as described in the
+     * <a href="{@docRoot}intro/appmodel.html#Threads">Threading section of
+     * the Application Model overview</a>.
+     */
+    public final String getWritePermission() {
+        return mWritePermission;
+    }
+
+    /**
+     * Called when the provider is being started.
+     *
+     * @return true if the provider was successfully loaded, false otherwise
+     */
+    public abstract boolean onCreate();
+
+    public void onConfigurationChanged(Configuration newConfig) {
+    }
+    
+    public void onLowMemory() {
+    }
+
+    /**
+     * Receives a query request from a client in a local process, and
+     * returns a Cursor. This is called internally by the {@link ContentResolver}.
+     * This method can be called from multiple
+     * threads, as described in the
+     * <a href="{@docRoot}intro/appmodel.html#Threads">Threading section of
+     * the Application Model overview</a>.
+     * <p>
+     * Example client call:<p>
+     * <pre>// Request a specific record.
+     * Cursor managedCursor = managedQuery(
+                Contacts.People.CONTENT_URI.addId(2),
+                projection,    // Which columns to return.
+                null,          // WHERE clause.
+                People.NAME + " ASC");   // Sort order.</pre>
+     * Example implementation:<p>
+     * <pre>// SQLiteQueryBuilder is a helper class that creates the
+        // proper SQL syntax for us.
+        SQLiteQueryBuilder qBuilder = new SQLiteQueryBuilder();
+
+        // Set the table we're querying.
+        qBuilder.setTables(DATABASE_TABLE_NAME);
+
+        // If the query ends in a specific record number, we're
+        // being asked for a specific record, so set the
+        // WHERE clause in our query.
+        if((URI_MATCHER.match(uri)) == SPECIFIC_MESSAGE){
+            qBuilder.appendWhere("_id=" + uri.getPathLeafId());
+        }
+
+        // Make the query.
+        Cursor c = qBuilder.query(mDb,
+                projection,
+                selection,
+                selectionArgs,
+                groupBy,
+                having,
+                sortOrder);
+        c.setNotificationUri(getContext().getContentResolver(), uri);
+        return c;</pre>
+     *
+     * @param uri The URI to query. This will be the full URI sent by the client;
+     * if the client is requesting a specific record, the URI will end in a record number
+     * that the implementation should parse and add to a WHERE or HAVING clause, specifying
+     * that _id value.
+     * @param projection The list of columns to put into the cursor. If
+     *      null all columns are included.
+     * @param selection A selection criteria to apply when filtering rows.
+     *      If null then all rows are included.
+     * @param sortOrder How the rows in the cursor should be sorted.
+     *        If null then the provider is free to define the sort order.
+     * @return a Cursor or null.
+     */
+    public abstract Cursor query(Uri uri, String[] projection,
+            String selection, String[] selectionArgs, String sortOrder);
+
+    /**
+     * Return the MIME type of the data at the given URI. This should start with
+     * <code>vnd.android.cursor.item</code> for a single record,
+     * or <code>vnd.android.cursor.dir/</code> for multiple items.
+     * This method can be called from multiple
+     * threads, as described in the
+     * <a href="{@docRoot}intro/appmodel.html#Threads">Threading section of
+     * the Application Model overview</a>.
+     *
+     * @param uri the URI to query.
+     * @return a MIME type string, or null if there is no type.
+     */
+    public abstract String getType(Uri uri);
+
+    /**
+     * Implement this to insert a new row.
+     * As a courtesy, call {@link ContentResolver#notifyChange(android.net.Uri ,android.database.ContentObserver) notifyChange()}
+     * after inserting.
+     * This method can be called from multiple
+     * threads, as described in the
+     * <a href="{@docRoot}intro/appmodel.html#Threads">Threading section of the
+     * Application Model overview</a>.
+     * @param uri The content:// URI of the insertion request.
+     * @param values A set of column_name/value pairs to add to the database.
+     * @return The URI for the newly inserted item.
+     */
+    public abstract Uri insert(Uri uri, ContentValues values);
+
+    /**
+     * Implement this to insert a set of new rows, or the default implementation will
+     * iterate over the values and call {@link #insert} on each of them.
+     * As a courtesy, call {@link ContentResolver#notifyChange(android.net.Uri ,android.database.ContentObserver) notifyChange()}
+     * after inserting.
+     * This method can be called from multiple
+     * threads, as described in the
+     * <a href="{@docRoot}intro/appmodel.html#Threads">Threading section of
+     * the Application Model overview</a>.
+     *
+     * @param uri The content:// URI of the insertion request.
+     * @param values An array of sets of column_name/value pairs to add to the database.
+     * @return The number of values that were inserted.
+     */
+    public int bulkInsert(Uri uri, ContentValues[] values) {
+        int numValues = values.length;
+        for (int i = 0; i < numValues; i++) {
+            insert(uri, values[i]);
+        }
+        return numValues;
+    }
+
+    /**
+     * A request to delete one or more rows. The selection clause is applied when performing
+     * the deletion, allowing the operation to affect multiple rows in a
+     * directory.
+     * As a courtesy, call {@link ContentResolver#notifyChange(android.net.Uri ,android.database.ContentObserver) notifyDelete()}
+     * after deleting.
+     * This method can be called from multiple
+     * threads, as described in the
+     * <a href="{@docRoot}intro/appmodel.html#Threads">Threading section of the
+     * Application Model overview</a>.
+     *
+     * <p>The implementation is responsible for parsing out a row ID at the end
+     * of the URI, if a specific row is being deleted. That is, the client would
+     * pass in <code>content://contacts/people/22</code> and the implementation is
+     * responsible for parsing the record number (22) when creating a SQL statement.
+     *
+     * @param uri The full URI to query, including a row ID (if a specific record is requested).
+     * @param selection An optional restriction to apply to rows when deleting.
+     * @return The number of rows affected.
+     * @throws SQLException
+     */
+    public abstract int delete(Uri uri, String selection, String[] selectionArgs);
+
+    /**
+     * Update a content URI. All rows matching the optionally provided selection
+     * will have their columns listed as the keys in the values map with the
+     * values of those keys.
+     * As a courtesy, call {@link ContentResolver#notifyChange(android.net.Uri ,android.database.ContentObserver) notifyChange()}
+     * after updating.
+     * This method can be called from multiple
+     * threads, as described in the
+     * <a href="{@docRoot}intro/appmodel.html#Threads">Threading section of the
+     * Application Model overview</a>.
+     *
+     * @param uri The URI to query. This can potentially have a record ID if this
+     * is an update request for a specific record.
+     * @param values A Bundle mapping from column names to new column values (NULL is a
+     *               valid value).
+     * @param selection An optional filter to match rows to update.
+     * @return the number of rows affected.
+     */
+    public abstract int update(Uri uri, ContentValues values, String selection,
+            String[] selectionArgs);
+
+    /**
+     * Open a file blob associated with a content URI.
+     * This method can be called from multiple
+     * threads, as described in the
+     * <a href="{@docRoot}intro/appmodel.html#Threads">Threading section of the
+     * Application Model overview</a>.
+     * 
+     * <p>Returns a
+     * ParcelFileDescriptor, from which you can obtain a
+     * {@link java.io.FileDescriptor} for use with
+     * {@link java.io.FileInputStream}, {@link java.io.FileOutputStream}, etc.
+     * This can be used to store large data (such as an image) associated with
+     * a particular piece of content.
+     *
+     * <p>The returned ParcelFileDescriptor is owned by the caller, so it is
+     * their responsibility to close it when done.  That is, the implementation
+     * of this method should create a new ParcelFileDescriptor for each call.
+     *
+     * @param uri The URI whose file is to be opened.
+     * @param mode Access mode for the file.  May be "r" for read-only access
+     * or "rw" for read and write access.
+     *
+     * @return Returns a new ParcelFileDescriptor which you can use to access
+     * the file.
+     *
+     * @throws FileNotFoundException Throws FileNotFoundException if there is
+     * no file associated with the given URI or the mode is invalid.
+     * @throws SecurityException Throws SecurityException if the caller does
+     * not have permission to access the file.
+     */
+    public ParcelFileDescriptor openFile(Uri uri, String mode)
+            throws FileNotFoundException {
+        throw new FileNotFoundException("No files supported by provider at "
+                + uri);
+    }
+
+    /**
+     * Convenience for subclasses that wish to implement {@link #openFile}
+     * by looking up a column named "_data" at the given URI.
+     *
+     * @param uri The URI to be opened.
+     * @param mode The file mode.
+     *
+     * @return Returns a new ParcelFileDescriptor that can be used by the
+     * client to access the file.
+     */
+    protected final ParcelFileDescriptor openFileHelper(Uri uri,
+            String mode) throws FileNotFoundException {
+        Cursor c = query(uri, new String[]{"_data"}, null, null, null);
+        int count = (c != null) ? c.getCount() : 0;
+        if (count != 1) {
+            // If there is not exactly one result, throw an appropriate
+            // exception.
+            if (c != null) {
+                c.close();
+            }
+            if (count == 0) {
+                throw new FileNotFoundException("No entry for " + uri);
+            }
+            throw new FileNotFoundException("Multiple items at " + uri);
+        }
+
+        c.moveToFirst();
+        int i = c.getColumnIndex("_data");
+        String path = (i >= 0 ? c.getString(i) : null);
+        c.close();
+        if (path == null) {
+            throw new FileNotFoundException("Column _data not found.");
+        }
+
+        int modeBits;
+        if ("r".equals(mode)) {
+            modeBits = ParcelFileDescriptor.MODE_READ_ONLY;
+        } else if ("rw".equals(mode)) {
+            modeBits = ParcelFileDescriptor.MODE_READ_WRITE
+                    | ParcelFileDescriptor.MODE_CREATE;
+        } else {
+            throw new FileNotFoundException("Bad mode for " + uri + ": "
+                    + mode);
+        }
+        return ParcelFileDescriptor.open(new File(path), modeBits);
+    }
+
+    /**
+     * Get the sync adapter that is to be used by this content provider.
+     * This is intended for use by the sync system. If null then this
+     * content provider is considered not syncable.
+     * This method can be called from multiple
+     * threads, as described in the
+     * <a href="{@docRoot}intro/appmodel.html#Threads">Threading section of
+     * the Application Model overview</a>.
+     * 
+     * @return the SyncAdapter that is to be used by this ContentProvider, or null
+     *   if this ContentProvider is not syncable
+     * @hide
+     */
+    public SyncAdapter getSyncAdapter() {
+        return null;
+    }
+
+    /**
+     * Returns true if this instance is a temporary content provider.
+     * @return true if this instance is a temporary content provider
+     */
+    protected boolean isTemporary() {
+        return false;
+    }
+
+    /**
+     * Returns the Binder object for this provider.
+     *
+     * @return the Binder object for this provider
+     * @hide
+     */
+    public IContentProvider getIContentProvider() {
+        return mTransport;
+    }
+
+    /**
+     * After being instantiated, this is called to tell the content provider
+     * about itself.
+     *
+     * @param context The context this provider is running in
+     * @param info Registered information about this content provider
+     */
+    public void attachInfo(Context context, ProviderInfo info) {
+
+        /*
+         * Only allow it to be set once, so after the content service gives
+         * this to us clients can't change it.
+         */
+        if (mContext == null) {
+            mContext = context;
+            if (info != null) {
+                setReadPermission(info.readPermission);
+                setWritePermission(info.writePermission);
+            }
+            ContentProvider.this.onCreate();
+        }
+    }
+}