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/*
* Copyright (C) 2012 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 com.android.cellbroadcastreceiver;
import android.content.ContentProvider;
import android.content.ContentProviderClient;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteQueryBuilder;
import android.net.Uri;
import android.os.AsyncTask;
import android.provider.Telephony;
import android.telephony.CellBroadcastMessage;
import android.text.TextUtils;
import android.util.Log;
/**
* ContentProvider for the database of received cell broadcasts.
*/
public class CellBroadcastContentProvider extends ContentProvider {
private static final String TAG = "CellBroadcastContentProvider";
/** URI matcher for ContentProvider queries. */
private static final UriMatcher sUriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
/** Authority string for content URIs. */
static final String CB_AUTHORITY = "cellbroadcasts";
/** Content URI for notifying observers. */
static final Uri CONTENT_URI = Uri.parse("content://cellbroadcasts/");
/** URI matcher type to get all cell broadcasts. */
private static final int CB_ALL = 0;
/** URI matcher type to get a cell broadcast by ID. */
private static final int CB_ALL_ID = 1;
/** MIME type for the list of all cell broadcasts. */
private static final String CB_LIST_TYPE = "vnd.android.cursor.dir/cellbroadcast";
/** MIME type for an individual cell broadcast. */
private static final String CB_TYPE = "vnd.android.cursor.item/cellbroadcast";
static {
sUriMatcher.addURI(CB_AUTHORITY, null, CB_ALL);
sUriMatcher.addURI(CB_AUTHORITY, "#", CB_ALL_ID);
}
/** The database for this content provider. */
private SQLiteOpenHelper mOpenHelper;
/**
* Initialize content provider.
* @return true if the provider was successfully loaded, false otherwise
*/
@Override
public boolean onCreate() {
mOpenHelper = new CellBroadcastDatabaseHelper(getContext());
return true;
}
/**
* Return a cursor for the cell broadcast table.
* @param uri the URI to query.
* @param projection the list of columns to put into the cursor, or null.
* @param selection the selection criteria to apply when filtering rows, or null.
* @param selectionArgs values to replace ?s in selection string.
* @param sortOrder how the rows in the cursor should be sorted, or null to sort from most
* recently received to least recently received.
* @return a Cursor or null.
*/
@Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
String sortOrder) {
SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
qb.setTables(CellBroadcastDatabaseHelper.TABLE_NAME);
int match = sUriMatcher.match(uri);
switch (match) {
case CB_ALL:
// get all broadcasts
break;
case CB_ALL_ID:
// get broadcast by ID
qb.appendWhere("(_id=" + uri.getPathSegments().get(0) + ')');
break;
default:
Log.e(TAG, "Invalid query: " + uri);
throw new IllegalArgumentException("Unknown URI: " + uri);
}
String orderBy;
if (!TextUtils.isEmpty(sortOrder)) {
orderBy = sortOrder;
} else {
orderBy = Telephony.CellBroadcasts.DEFAULT_SORT_ORDER;
}
SQLiteDatabase db = mOpenHelper.getReadableDatabase();
Cursor c = qb.query(db, projection, selection, selectionArgs, null, null, orderBy);
if (c != null) {
c.setNotificationUri(getContext().getContentResolver(), CONTENT_URI);
}
return c;
}
/**
* Return the MIME type of the data at the specified URI.
* @param uri the URI to query.
* @return a MIME type string, or null if there is no type.
*/
@Override
public String getType(Uri uri) {
int match = sUriMatcher.match(uri);
switch (match) {
case CB_ALL:
return CB_LIST_TYPE;
case CB_ALL_ID:
return CB_TYPE;
default:
return null;
}
}
/**
* Insert a new row. This throws an exception, as the database can only be modified by
* calling custom methods in this class, and not via the ContentProvider interface.
* @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.
*/
@Override
public Uri insert(Uri uri, ContentValues values) {
throw new UnsupportedOperationException("insert not supported");
}
/**
* Delete one or more rows. This throws an exception, as the database can only be modified by
* calling custom methods in this class, and not via the ContentProvider interface.
* @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.
*/
@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
throw new UnsupportedOperationException("delete not supported");
}
/**
* Update one or more rows. This throws an exception, as the database can only be modified by
* calling custom methods in this class, and not via the ContentProvider interface.
* @param uri the URI to query, potentially including the row ID.
* @param values a Bundle mapping from column names to new column values.
* @param selection an optional filter to match rows to update.
* @return the number of rows affected.
*/
@Override
public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
throw new UnsupportedOperationException("update not supported");
}
/**
* Internal method to insert a new Cell Broadcast into the database and notify observers.
* @param message the message to insert
* @return true if the broadcast is new, false if it's a duplicate broadcast.
*/
boolean insertNewBroadcast(CellBroadcastMessage message) {
SQLiteDatabase db = mOpenHelper.getWritableDatabase();
ContentValues cv = message.getContentValues();
// Note: this method previously queried the database for duplicate message IDs, but this
// is not compatible with CMAS carrier requirements and could also cause other emergency
// alerts, e.g. ETWS, to not display if the database is filled with old messages.
// Use duplicate message ID detection in CellBroadcastAlertService instead of DB query.
long rowId = db.insert(CellBroadcastDatabaseHelper.TABLE_NAME, null, cv);
if (rowId == -1) {
Log.e(TAG, "failed to insert new broadcast into database");
// Return true on DB write failure because we still want to notify the user.
// The CellBroadcastMessage will be passed with the intent, so the message will be
// displayed in the emergency alert dialog, or the dialog that is displayed when
// the user selects the notification for a non-emergency broadcast, even if the
// broadcast could not be written to the database.
}
return true; // broadcast is not a duplicate
}
/**
* Internal method to delete a cell broadcast by row ID and notify observers.
* @param rowId the row ID of the broadcast to delete
* @return true if the database was updated, false otherwise
*/
boolean deleteBroadcast(long rowId) {
SQLiteDatabase db = mOpenHelper.getWritableDatabase();
int rowCount = db.delete(CellBroadcastDatabaseHelper.TABLE_NAME,
Telephony.CellBroadcasts._ID + "=?",
new String[]{Long.toString(rowId)});
if (rowCount != 0) {
return true;
} else {
Log.e(TAG, "failed to delete broadcast at row " + rowId);
return false;
}
}
/**
* Internal method to delete all cell broadcasts and notify observers.
* @return true if the database was updated, false otherwise
*/
boolean deleteAllBroadcasts() {
SQLiteDatabase db = mOpenHelper.getWritableDatabase();
int rowCount = db.delete(CellBroadcastDatabaseHelper.TABLE_NAME, null, null);
if (rowCount != 0) {
return true;
} else {
Log.e(TAG, "failed to delete all broadcasts");
return false;
}
}
/**
* Internal method to mark a broadcast as read and notify observers. The broadcast can be
* identified by delivery time (for new alerts) or by row ID. The caller is responsible for
* decrementing the unread non-emergency alert count, if necessary.
*
* @param columnName the column name to query (ID or delivery time)
* @param columnValue the ID or delivery time of the broadcast to mark read
* @return true if the database was updated, false otherwise
*/
boolean markBroadcastRead(String columnName, long columnValue) {
SQLiteDatabase db = mOpenHelper.getWritableDatabase();
ContentValues cv = new ContentValues(1);
cv.put(Telephony.CellBroadcasts.MESSAGE_READ, 1);
String whereClause = columnName + "=?";
String[] whereArgs = new String[]{Long.toString(columnValue)};
int rowCount = db.update(CellBroadcastDatabaseHelper.TABLE_NAME, cv, whereClause, whereArgs);
if (rowCount != 0) {
return true;
} else {
Log.e(TAG, "failed to mark broadcast read: " + columnName + " = " + columnValue);
return false;
}
}
/** Callback for users of AsyncCellBroadcastOperation. */
interface CellBroadcastOperation {
/**
* Perform an operation using the specified provider.
* @param provider the CellBroadcastContentProvider to use
* @return true if any rows were changed, false otherwise
*/
boolean execute(CellBroadcastContentProvider provider);
}
/**
* Async task to call this content provider's internal methods on a background thread.
* The caller supplies the CellBroadcastOperation object to call for this provider.
*/
static class AsyncCellBroadcastTask extends AsyncTask<CellBroadcastOperation, Void, Void> {
/** Reference to this app's content resolver. */
private ContentResolver mContentResolver;
AsyncCellBroadcastTask(ContentResolver contentResolver) {
mContentResolver = contentResolver;
}
/**
* Perform a generic operation on the CellBroadcastContentProvider.
* @param params the CellBroadcastOperation object to call for this provider
* @return void
*/
@Override
protected Void doInBackground(CellBroadcastOperation... params) {
ContentProviderClient cpc = mContentResolver.acquireContentProviderClient(
CellBroadcastContentProvider.CB_AUTHORITY);
CellBroadcastContentProvider provider = (CellBroadcastContentProvider)
cpc.getLocalContentProvider();
if (provider != null) {
try {
boolean changed = params[0].execute(provider);
if (changed) {
Log.d(TAG, "database changed: notifying observers...");
mContentResolver.notifyChange(CONTENT_URI, null, false);
}
} finally {
cpc.release();
}
} else {
Log.e(TAG, "getLocalContentProvider() returned null");
}
mContentResolver = null; // free reference to content resolver
return null;
}
}
}