| /* |
| * Copyright (C) 2008 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.providers.downloads; |
| |
| import android.content.ContentUris; |
| import android.content.Context; |
| import android.content.Intent; |
| import android.content.pm.PackageManager; |
| import android.content.pm.ResolveInfo; |
| import android.database.Cursor; |
| import android.drm.mobile1.DrmRawContent; |
| import android.net.ConnectivityManager; |
| import android.net.NetworkInfo; |
| import android.net.Uri; |
| import android.os.Environment; |
| import android.os.StatFs; |
| import android.os.SystemClock; |
| import android.provider.Downloads; |
| import android.telephony.TelephonyManager; |
| import android.util.Config; |
| import android.util.Log; |
| import android.webkit.MimeTypeMap; |
| |
| import java.io.File; |
| import java.io.FileNotFoundException; |
| import java.io.FileOutputStream; |
| import java.util.Random; |
| import java.util.Set; |
| import java.util.regex.Matcher; |
| import java.util.regex.Pattern; |
| |
| /** |
| * Some helper functions for the download manager |
| */ |
| public class Helpers { |
| |
| public static Random sRandom = new Random(SystemClock.uptimeMillis()); |
| |
| /** Regex used to parse content-disposition headers */ |
| private static final Pattern CONTENT_DISPOSITION_PATTERN = |
| Pattern.compile("attachment;\\s*filename\\s*=\\s*\"([^\"]*)\""); |
| |
| private Helpers() { |
| } |
| |
| /* |
| * Parse the Content-Disposition HTTP Header. The format of the header |
| * is defined here: http://www.w3.org/Protocols/rfc2616/rfc2616-sec19.html |
| * This header provides a filename for content that is going to be |
| * downloaded to the file system. We only support the attachment type. |
| */ |
| private static String parseContentDisposition(String contentDisposition) { |
| try { |
| Matcher m = CONTENT_DISPOSITION_PATTERN.matcher(contentDisposition); |
| if (m.find()) { |
| return m.group(1); |
| } |
| } catch (IllegalStateException ex) { |
| // This function is defined as returning null when it can't parse the header |
| } |
| return null; |
| } |
| |
| /** |
| * Creates a filename (where the file should be saved) from a uri. |
| */ |
| public static DownloadFileInfo generateSaveFile( |
| Context context, |
| String url, |
| String hint, |
| String contentDisposition, |
| String contentLocation, |
| String mimeType, |
| int destination, |
| int contentLength) throws FileNotFoundException { |
| |
| /* |
| * Don't download files that we won't be able to handle |
| */ |
| if (destination == Downloads.DESTINATION_EXTERNAL |
| || destination == Downloads.DESTINATION_CACHE_PARTITION_PURGEABLE) { |
| if (mimeType == null) { |
| if (Config.LOGD) { |
| Log.d(Constants.TAG, "external download with no mime type not allowed"); |
| } |
| return new DownloadFileInfo(null, null, Downloads.STATUS_NOT_ACCEPTABLE); |
| } |
| if (!DrmRawContent.DRM_MIMETYPE_MESSAGE_STRING.equalsIgnoreCase(mimeType)) { |
| // Check to see if we are allowed to download this file. Only files |
| // that can be handled by the platform can be downloaded. |
| // special case DRM files, which we should always allow downloading. |
| Intent intent = new Intent(Intent.ACTION_VIEW); |
| |
| // We can provide data as either content: or file: URIs, |
| // so allow both. (I think it would be nice if we just did |
| // everything as content: URIs) |
| // Actually, right now the download manager's UId restrictions |
| // prevent use from using content: so it's got to be file: or |
| // nothing |
| |
| PackageManager pm = context.getPackageManager(); |
| intent.setDataAndType(Uri.fromParts("file", "", null), mimeType); |
| ResolveInfo ri = pm.resolveActivity(intent, PackageManager.MATCH_DEFAULT_ONLY); |
| //Log.i(Constants.TAG, "*** FILENAME QUERY " + intent + ": " + list); |
| |
| if (ri == null) { |
| if (Config.LOGD) { |
| Log.d(Constants.TAG, "no handler found for type " + mimeType); |
| } |
| return new DownloadFileInfo(null, null, Downloads.STATUS_NOT_ACCEPTABLE); |
| } |
| } |
| } |
| String filename = chooseFilename( |
| url, hint, contentDisposition, contentLocation, destination); |
| |
| // Split filename between base and extension |
| // Add an extension if filename does not have one |
| String extension = null; |
| int dotIndex = filename.indexOf('.'); |
| if (dotIndex < 0) { |
| extension = chooseExtensionFromMimeType(mimeType, true); |
| } else { |
| extension = chooseExtensionFromFilename( |
| mimeType, destination, filename, dotIndex); |
| filename = filename.substring(0, dotIndex); |
| } |
| |
| /* |
| * Locate the directory where the file will be saved |
| */ |
| |
| File base = null; |
| StatFs stat = null; |
| // DRM messages should be temporarily stored internally and then passed to |
| // the DRM content provider |
| if (destination == Downloads.DESTINATION_CACHE_PARTITION |
| || destination == Downloads.DESTINATION_CACHE_PARTITION_PURGEABLE |
| || destination == Downloads.DESTINATION_CACHE_PARTITION_NOROAMING |
| || DrmRawContent.DRM_MIMETYPE_MESSAGE_STRING.equalsIgnoreCase(mimeType)) { |
| base = Environment.getDownloadCacheDirectory(); |
| stat = new StatFs(base.getPath()); |
| |
| /* |
| * Check whether there's enough space on the target filesystem to save the file. |
| * Put a bit of margin (in case creating the file grows the system by a few blocks). |
| */ |
| int blockSize = stat.getBlockSize(); |
| for (;;) { |
| int availableBlocks = stat.getAvailableBlocks(); |
| if (blockSize * ((long) availableBlocks - 4) >= contentLength) { |
| break; |
| } |
| if (!discardPurgeableFiles(context, |
| contentLength - blockSize * ((long) availableBlocks - 4))) { |
| if (Config.LOGD) { |
| Log.d(Constants.TAG, |
| "download aborted - not enough free space in internal storage"); |
| } |
| return new DownloadFileInfo(null, null, Downloads.STATUS_FILE_ERROR); |
| } |
| stat.restat(base.getPath()); |
| } |
| |
| } else { |
| if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) { |
| String root = Environment.getExternalStorageDirectory().getPath(); |
| base = new File(root + Constants.DEFAULT_DL_SUBDIR); |
| if (!base.isDirectory() && !base.mkdir()) { |
| if (Config.LOGD) { |
| Log.d(Constants.TAG, "download aborted - can't create base directory " |
| + base.getPath()); |
| } |
| return new DownloadFileInfo(null, null, Downloads.STATUS_FILE_ERROR); |
| } |
| stat = new StatFs(base.getPath()); |
| } else { |
| if (Config.LOGD) { |
| Log.d(Constants.TAG, "download aborted - no external storage"); |
| } |
| return new DownloadFileInfo(null, null, Downloads.STATUS_FILE_ERROR); |
| } |
| |
| /* |
| * Check whether there's enough space on the target filesystem to save the file. |
| * Put a bit of margin (in case creating the file grows the system by a few blocks). |
| */ |
| if (stat.getBlockSize() * ((long) stat.getAvailableBlocks() - 4) < contentLength) { |
| if (Config.LOGD) { |
| Log.d(Constants.TAG, "download aborted - not enough free space"); |
| } |
| return new DownloadFileInfo(null, null, Downloads.STATUS_FILE_ERROR); |
| } |
| |
| } |
| |
| boolean recoveryDir = Constants.RECOVERY_DIRECTORY.equalsIgnoreCase(filename + extension); |
| |
| filename = base.getPath() + File.separator + filename; |
| |
| /* |
| * Generate a unique filename, create the file, return it. |
| */ |
| if (Constants.LOGVV) { |
| Log.v(Constants.TAG, "target file: " + filename + extension); |
| } |
| |
| String fullFilename = chooseUniqueFilename( |
| destination, filename, extension, recoveryDir); |
| if (fullFilename != null) { |
| return new DownloadFileInfo(fullFilename, new FileOutputStream(fullFilename), 0); |
| } else { |
| return new DownloadFileInfo(null, null, Downloads.STATUS_FILE_ERROR); |
| } |
| } |
| |
| private static String chooseFilename(String url, String hint, String contentDisposition, |
| String contentLocation, int destination) { |
| String filename = null; |
| |
| // First, try to use the hint from the application, if there's one |
| if (filename == null && hint != null && !hint.endsWith("/")) { |
| if (Constants.LOGVV) { |
| Log.v(Constants.TAG, "getting filename from hint"); |
| } |
| int index = hint.lastIndexOf('/') + 1; |
| if (index > 0) { |
| filename = hint.substring(index); |
| } else { |
| filename = hint; |
| } |
| } |
| |
| // If we couldn't do anything with the hint, move toward the content disposition |
| if (filename == null && contentDisposition != null) { |
| filename = parseContentDisposition(contentDisposition); |
| if (filename != null) { |
| if (Constants.LOGVV) { |
| Log.v(Constants.TAG, "getting filename from content-disposition"); |
| } |
| int index = filename.lastIndexOf('/') + 1; |
| if (index > 0) { |
| filename = filename.substring(index); |
| } |
| } |
| } |
| |
| // If we still have nothing at this point, try the content location |
| if (filename == null && contentLocation != null) { |
| String decodedContentLocation = Uri.decode(contentLocation); |
| if (decodedContentLocation != null |
| && !decodedContentLocation.endsWith("/") |
| && decodedContentLocation.indexOf('?') < 0) { |
| if (Constants.LOGVV) { |
| Log.v(Constants.TAG, "getting filename from content-location"); |
| } |
| int index = decodedContentLocation.lastIndexOf('/') + 1; |
| if (index > 0) { |
| filename = decodedContentLocation.substring(index); |
| } else { |
| filename = decodedContentLocation; |
| } |
| } |
| } |
| |
| // If all the other http-related approaches failed, use the plain uri |
| if (filename == null) { |
| String decodedUrl = Uri.decode(url); |
| if (decodedUrl != null |
| && !decodedUrl.endsWith("/") && decodedUrl.indexOf('?') < 0) { |
| int index = decodedUrl.lastIndexOf('/') + 1; |
| if (index > 0) { |
| if (Constants.LOGVV) { |
| Log.v(Constants.TAG, "getting filename from uri"); |
| } |
| filename = decodedUrl.substring(index); |
| } |
| } |
| } |
| |
| // Finally, if couldn't get filename from URI, get a generic filename |
| if (filename == null) { |
| if (Constants.LOGVV) { |
| Log.v(Constants.TAG, "using default filename"); |
| } |
| filename = Constants.DEFAULT_DL_FILENAME; |
| } |
| |
| filename = filename.replaceAll("[^a-zA-Z0-9\\.\\-_]+", "_"); |
| |
| |
| return filename; |
| } |
| |
| private static String chooseExtensionFromMimeType(String mimeType, boolean useDefaults) { |
| String extension = null; |
| if (mimeType != null) { |
| extension = MimeTypeMap.getSingleton().getExtensionFromMimeType(mimeType); |
| if (extension != null) { |
| if (Constants.LOGVV) { |
| Log.v(Constants.TAG, "adding extension from type"); |
| } |
| extension = "." + extension; |
| } else { |
| if (Constants.LOGVV) { |
| Log.v(Constants.TAG, "couldn't find extension for " + mimeType); |
| } |
| } |
| } |
| if (extension == null) { |
| if (mimeType != null && mimeType.toLowerCase().startsWith("text/")) { |
| if (mimeType.equalsIgnoreCase("text/html")) { |
| if (Constants.LOGVV) { |
| Log.v(Constants.TAG, "adding default html extension"); |
| } |
| extension = Constants.DEFAULT_DL_HTML_EXTENSION; |
| } else if (useDefaults) { |
| if (Constants.LOGVV) { |
| Log.v(Constants.TAG, "adding default text extension"); |
| } |
| extension = Constants.DEFAULT_DL_TEXT_EXTENSION; |
| } |
| } else if (useDefaults) { |
| if (Constants.LOGVV) { |
| Log.v(Constants.TAG, "adding default binary extension"); |
| } |
| extension = Constants.DEFAULT_DL_BINARY_EXTENSION; |
| } |
| } |
| return extension; |
| } |
| |
| private static String chooseExtensionFromFilename(String mimeType, int destination, |
| String filename, int dotIndex) { |
| String extension = null; |
| if (mimeType != null) { |
| // Compare the last segment of the extension against the mime type. |
| // If there's a mismatch, discard the entire extension. |
| int lastDotIndex = filename.lastIndexOf('.'); |
| String typeFromExt = MimeTypeMap.getSingleton().getMimeTypeFromExtension( |
| filename.substring(lastDotIndex + 1)); |
| if (typeFromExt == null || !typeFromExt.equalsIgnoreCase(mimeType)) { |
| extension = chooseExtensionFromMimeType(mimeType, false); |
| if (extension != null) { |
| if (Constants.LOGVV) { |
| Log.v(Constants.TAG, "substituting extension from type"); |
| } |
| } else { |
| if (Constants.LOGVV) { |
| Log.v(Constants.TAG, "couldn't find extension for " + mimeType); |
| } |
| } |
| } |
| } |
| if (extension == null) { |
| if (Constants.LOGVV) { |
| Log.v(Constants.TAG, "keeping extension"); |
| } |
| extension = filename.substring(dotIndex); |
| } |
| return extension; |
| } |
| |
| private static String chooseUniqueFilename(int destination, String filename, |
| String extension, boolean recoveryDir) { |
| String fullFilename = filename + extension; |
| if (!new File(fullFilename).exists() |
| && (!recoveryDir || |
| (destination != Downloads.DESTINATION_CACHE_PARTITION && |
| destination != Downloads.DESTINATION_CACHE_PARTITION_PURGEABLE && |
| destination != Downloads.DESTINATION_CACHE_PARTITION_NOROAMING))) { |
| return fullFilename; |
| } |
| filename = filename + Constants.FILENAME_SEQUENCE_SEPARATOR; |
| /* |
| * This number is used to generate partially randomized filenames to avoid |
| * collisions. |
| * It starts at 1. |
| * The next 9 iterations increment it by 1 at a time (up to 10). |
| * The next 9 iterations increment it by 1 to 10 (random) at a time. |
| * The next 9 iterations increment it by 1 to 100 (random) at a time. |
| * ... Up to the point where it increases by 100000000 at a time. |
| * (the maximum value that can be reached is 1000000000) |
| * As soon as a number is reached that generates a filename that doesn't exist, |
| * that filename is used. |
| * If the filename coming in is [base].[ext], the generated filenames are |
| * [base]-[sequence].[ext]. |
| */ |
| int sequence = 1; |
| for (int magnitude = 1; magnitude < 1000000000; magnitude *= 10) { |
| for (int iteration = 0; iteration < 9; ++iteration) { |
| fullFilename = filename + sequence + extension; |
| if (!new File(fullFilename).exists()) { |
| return fullFilename; |
| } |
| if (Constants.LOGVV) { |
| Log.v(Constants.TAG, "file with sequence number " + sequence + " exists"); |
| } |
| sequence += sRandom.nextInt(magnitude) + 1; |
| } |
| } |
| return null; |
| } |
| |
| /** |
| * Deletes purgeable files from the cache partition. This also deletes |
| * the matching database entries. Files are deleted in LRU order until |
| * the total byte size is greater than targetBytes. |
| */ |
| public static final boolean discardPurgeableFiles(Context context, long targetBytes) { |
| Cursor cursor = context.getContentResolver().query( |
| Downloads.CONTENT_URI, |
| null, |
| "( " + |
| Downloads.COLUMN_STATUS + " = '" + Downloads.STATUS_SUCCESS + "' AND " + |
| Downloads.COLUMN_DESTINATION + |
| " = '" + Downloads.DESTINATION_CACHE_PARTITION_PURGEABLE + "' )", |
| null, |
| Downloads.COLUMN_LAST_MODIFICATION); |
| if (cursor == null) { |
| return false; |
| } |
| long totalFreed = 0; |
| try { |
| cursor.moveToFirst(); |
| while (!cursor.isAfterLast() && totalFreed < targetBytes) { |
| File file = new File(cursor.getString(cursor.getColumnIndex(Downloads._DATA))); |
| if (Constants.LOGVV) { |
| Log.v(Constants.TAG, "purging " + file.getAbsolutePath() + " for " + |
| file.length() + " bytes"); |
| } |
| totalFreed += file.length(); |
| file.delete(); |
| long id = cursor.getLong(cursor.getColumnIndex(Downloads._ID)); |
| context.getContentResolver().delete( |
| ContentUris.withAppendedId(Downloads.CONTENT_URI, id), null, null); |
| cursor.moveToNext(); |
| } |
| } finally { |
| cursor.close(); |
| } |
| if (Constants.LOGV) { |
| if (totalFreed > 0) { |
| Log.v(Constants.TAG, "Purged files, freed " + totalFreed + " for " + |
| targetBytes + " requested"); |
| } |
| } |
| return totalFreed > 0; |
| } |
| |
| /** |
| * Returns whether the network is available |
| */ |
| public static boolean isNetworkAvailable(Context context) { |
| ConnectivityManager connectivity = |
| (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE); |
| if (connectivity == null) { |
| Log.w(Constants.TAG, "couldn't get connectivity manager"); |
| } else { |
| NetworkInfo[] info = connectivity.getAllNetworkInfo(); |
| if (info != null) { |
| for (int i = 0; i < info.length; i++) { |
| if (info[i].getState() == NetworkInfo.State.CONNECTED) { |
| if (Constants.LOGVV) { |
| Log.v(Constants.TAG, "network is available"); |
| } |
| return true; |
| } |
| } |
| } |
| } |
| if (Constants.LOGVV) { |
| Log.v(Constants.TAG, "network is not available"); |
| } |
| return false; |
| } |
| |
| /** |
| * Returns whether the network is roaming |
| */ |
| public static boolean isNetworkRoaming(Context context) { |
| ConnectivityManager connectivity = |
| (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE); |
| if (connectivity == null) { |
| Log.w(Constants.TAG, "couldn't get connectivity manager"); |
| } else { |
| NetworkInfo info = connectivity.getActiveNetworkInfo(); |
| if (info != null && info.getType() == ConnectivityManager.TYPE_MOBILE) { |
| if (TelephonyManager.getDefault().isNetworkRoaming()) { |
| if (Constants.LOGVV) { |
| Log.v(Constants.TAG, "network is roaming"); |
| } |
| return true; |
| } else { |
| if (Constants.LOGVV) { |
| Log.v(Constants.TAG, "network is not roaming"); |
| } |
| } |
| } else { |
| if (Constants.LOGVV) { |
| Log.v(Constants.TAG, "not using mobile network"); |
| } |
| } |
| } |
| return false; |
| } |
| |
| /** |
| * Checks whether the filename looks legitimate |
| */ |
| public static boolean isFilenameValid(String filename) { |
| File dir = new File(filename).getParentFile(); |
| return dir.equals(Environment.getDownloadCacheDirectory()) |
| || dir.equals(new File(Environment.getExternalStorageDirectory() |
| + Constants.DEFAULT_DL_SUBDIR)); |
| } |
| |
| /** |
| * Checks whether this looks like a legitimate selection parameter |
| */ |
| public static void validateSelection(String selection, Set<String> allowedColumns) { |
| try { |
| if (selection == null) { |
| return; |
| } |
| Lexer lexer = new Lexer(selection, allowedColumns); |
| parseExpression(lexer); |
| if (lexer.currentToken() != Lexer.TOKEN_END) { |
| throw new IllegalArgumentException("syntax error"); |
| } |
| } catch (RuntimeException ex) { |
| if (Constants.LOGV) { |
| Log.d(Constants.TAG, "invalid selection [" + selection + "] triggered " + ex); |
| } else if (Config.LOGD) { |
| Log.d(Constants.TAG, "invalid selection triggered " + ex); |
| } |
| throw ex; |
| } |
| |
| } |
| |
| // expression <- ( expression ) | statement [AND_OR ( expression ) | statement] * |
| // | statement [AND_OR expression]* |
| private static void parseExpression(Lexer lexer) { |
| for (;;) { |
| // ( expression ) |
| if (lexer.currentToken() == Lexer.TOKEN_OPEN_PAREN) { |
| lexer.advance(); |
| parseExpression(lexer); |
| if (lexer.currentToken() != Lexer.TOKEN_CLOSE_PAREN) { |
| throw new IllegalArgumentException("syntax error, unmatched parenthese"); |
| } |
| lexer.advance(); |
| } else { |
| // statement |
| parseStatement(lexer); |
| } |
| if (lexer.currentToken() != Lexer.TOKEN_AND_OR) { |
| break; |
| } |
| lexer.advance(); |
| } |
| } |
| |
| // statement <- COLUMN COMPARE VALUE |
| // | COLUMN IS NULL |
| private static void parseStatement(Lexer lexer) { |
| // both possibilities start with COLUMN |
| if (lexer.currentToken() != Lexer.TOKEN_COLUMN) { |
| throw new IllegalArgumentException("syntax error, expected column name"); |
| } |
| lexer.advance(); |
| |
| // statement <- COLUMN COMPARE VALUE |
| if (lexer.currentToken() == Lexer.TOKEN_COMPARE) { |
| lexer.advance(); |
| if (lexer.currentToken() != Lexer.TOKEN_VALUE) { |
| throw new IllegalArgumentException("syntax error, expected quoted string"); |
| } |
| lexer.advance(); |
| return; |
| } |
| |
| // statement <- COLUMN IS NULL |
| if (lexer.currentToken() == Lexer.TOKEN_IS) { |
| lexer.advance(); |
| if (lexer.currentToken() != Lexer.TOKEN_NULL) { |
| throw new IllegalArgumentException("syntax error, expected NULL"); |
| } |
| lexer.advance(); |
| return; |
| } |
| |
| // didn't get anything good after COLUMN |
| throw new IllegalArgumentException("syntax error after column name"); |
| } |
| |
| /** |
| * A simple lexer that recognizes the words of our restricted subset of SQL where clauses |
| */ |
| private static class Lexer { |
| public static final int TOKEN_START = 0; |
| public static final int TOKEN_OPEN_PAREN = 1; |
| public static final int TOKEN_CLOSE_PAREN = 2; |
| public static final int TOKEN_AND_OR = 3; |
| public static final int TOKEN_COLUMN = 4; |
| public static final int TOKEN_COMPARE = 5; |
| public static final int TOKEN_VALUE = 6; |
| public static final int TOKEN_IS = 7; |
| public static final int TOKEN_NULL = 8; |
| public static final int TOKEN_END = 9; |
| |
| private final String mSelection; |
| private final Set<String> mAllowedColumns; |
| private int mOffset = 0; |
| private int mCurrentToken = TOKEN_START; |
| private final char[] mChars; |
| |
| public Lexer(String selection, Set<String> allowedColumns) { |
| mSelection = selection; |
| mAllowedColumns = allowedColumns; |
| mChars = new char[mSelection.length()]; |
| mSelection.getChars(0, mChars.length, mChars, 0); |
| advance(); |
| } |
| |
| public int currentToken() { |
| return mCurrentToken; |
| } |
| |
| public void advance() { |
| char[] chars = mChars; |
| |
| // consume whitespace |
| while (mOffset < chars.length && chars[mOffset] == ' ') { |
| ++mOffset; |
| } |
| |
| // end of input |
| if (mOffset == chars.length) { |
| mCurrentToken = TOKEN_END; |
| return; |
| } |
| |
| // "(" |
| if (chars[mOffset] == '(') { |
| ++mOffset; |
| mCurrentToken = TOKEN_OPEN_PAREN; |
| return; |
| } |
| |
| // ")" |
| if (chars[mOffset] == ')') { |
| ++mOffset; |
| mCurrentToken = TOKEN_CLOSE_PAREN; |
| return; |
| } |
| |
| // "?" |
| if (chars[mOffset] == '?') { |
| ++mOffset; |
| mCurrentToken = TOKEN_VALUE; |
| return; |
| } |
| |
| // "=" and "==" |
| if (chars[mOffset] == '=') { |
| ++mOffset; |
| mCurrentToken = TOKEN_COMPARE; |
| if (mOffset < chars.length && chars[mOffset] == '=') { |
| ++mOffset; |
| } |
| return; |
| } |
| |
| // ">" and ">=" |
| if (chars[mOffset] == '>') { |
| ++mOffset; |
| mCurrentToken = TOKEN_COMPARE; |
| if (mOffset < chars.length && chars[mOffset] == '=') { |
| ++mOffset; |
| } |
| return; |
| } |
| |
| // "<", "<=" and "<>" |
| if (chars[mOffset] == '<') { |
| ++mOffset; |
| mCurrentToken = TOKEN_COMPARE; |
| if (mOffset < chars.length && (chars[mOffset] == '=' || chars[mOffset] == '>')) { |
| ++mOffset; |
| } |
| return; |
| } |
| |
| // "!=" |
| if (chars[mOffset] == '!') { |
| ++mOffset; |
| mCurrentToken = TOKEN_COMPARE; |
| if (mOffset < chars.length && chars[mOffset] == '=') { |
| ++mOffset; |
| return; |
| } |
| throw new IllegalArgumentException("Unexpected character after !"); |
| } |
| |
| // columns and keywords |
| // first look for anything that looks like an identifier or a keyword |
| // and then recognize the individual words. |
| // no attempt is made at discarding sequences of underscores with no alphanumeric |
| // characters, even though it's not clear that they'd be legal column names. |
| if (isIdentifierStart(chars[mOffset])) { |
| int startOffset = mOffset; |
| ++mOffset; |
| while (mOffset < chars.length && isIdentifierChar(chars[mOffset])) { |
| ++mOffset; |
| } |
| String word = mSelection.substring(startOffset, mOffset); |
| if (mOffset - startOffset <= 4) { |
| if (word.equals("IS")) { |
| mCurrentToken = TOKEN_IS; |
| return; |
| } |
| if (word.equals("OR") || word.equals("AND")) { |
| mCurrentToken = TOKEN_AND_OR; |
| return; |
| } |
| if (word.equals("NULL")) { |
| mCurrentToken = TOKEN_NULL; |
| return; |
| } |
| } |
| if (mAllowedColumns.contains(word)) { |
| mCurrentToken = TOKEN_COLUMN; |
| return; |
| } |
| throw new IllegalArgumentException("unrecognized column or keyword"); |
| } |
| |
| // quoted strings |
| if (chars[mOffset] == '\'') { |
| ++mOffset; |
| while (mOffset < chars.length) { |
| if (chars[mOffset] == '\'') { |
| if (mOffset + 1 < chars.length && chars[mOffset + 1] == '\'') { |
| ++mOffset; |
| } else { |
| break; |
| } |
| } |
| ++mOffset; |
| } |
| if (mOffset == chars.length) { |
| throw new IllegalArgumentException("unterminated string"); |
| } |
| ++mOffset; |
| mCurrentToken = TOKEN_VALUE; |
| return; |
| } |
| |
| // anything we don't recognize |
| throw new IllegalArgumentException("illegal character"); |
| } |
| |
| private static final boolean isIdentifierStart(char c) { |
| return c == '_' || |
| (c >= 'A' && c <= 'Z') || |
| (c >= 'a' && c <= 'z'); |
| } |
| |
| private static final boolean isIdentifierChar(char c) { |
| return c == '_' || |
| (c >= 'A' && c <= 'Z') || |
| (c >= 'a' && c <= 'z') || |
| (c >= '0' && c <= '9'); |
| } |
| } |
| } |
