| /* |
| * 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 static android.os.Environment.buildExternalStorageAppCacheDirs; |
| import static android.os.Environment.buildExternalStorageAppFilesDirs; |
| import static android.os.Environment.buildExternalStorageAppMediaDirs; |
| import static android.os.Environment.buildExternalStorageAppObbDirs; |
| import static android.provider.Downloads.Impl.FLAG_REQUIRES_CHARGING; |
| import static android.provider.Downloads.Impl.FLAG_REQUIRES_DEVICE_IDLE; |
| |
| import static com.android.providers.downloads.Constants.TAG; |
| |
| import android.app.job.JobInfo; |
| import android.app.job.JobScheduler; |
| import android.content.ComponentName; |
| import android.content.Context; |
| import android.database.Cursor; |
| import android.net.Uri; |
| import android.os.Environment; |
| import android.os.FileUtils; |
| import android.os.Handler; |
| import android.os.HandlerThread; |
| import android.os.Process; |
| import android.os.SystemClock; |
| import android.os.UserHandle; |
| import android.os.storage.StorageManager; |
| import android.os.storage.StorageVolume; |
| import android.provider.Downloads; |
| import android.text.TextUtils; |
| import android.util.Log; |
| import android.webkit.MimeTypeMap; |
| |
| import com.google.common.annotations.VisibleForTesting; |
| |
| import java.io.File; |
| import java.io.IOException; |
| 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 static final Object sUniqueLock = new Object(); |
| |
| private static HandlerThread sAsyncHandlerThread; |
| private static Handler sAsyncHandler; |
| |
| private static SystemFacade sSystemFacade; |
| private static DownloadNotifier sNotifier; |
| |
| private Helpers() { |
| } |
| |
| public synchronized static Handler getAsyncHandler() { |
| if (sAsyncHandlerThread == null) { |
| sAsyncHandlerThread = new HandlerThread("sAsyncHandlerThread", |
| Process.THREAD_PRIORITY_BACKGROUND); |
| sAsyncHandlerThread.start(); |
| sAsyncHandler = new Handler(sAsyncHandlerThread.getLooper()); |
| } |
| return sAsyncHandler; |
| } |
| |
| @VisibleForTesting |
| public synchronized static void setSystemFacade(SystemFacade systemFacade) { |
| sSystemFacade = systemFacade; |
| } |
| |
| public synchronized static SystemFacade getSystemFacade(Context context) { |
| if (sSystemFacade == null) { |
| sSystemFacade = new RealSystemFacade(context); |
| } |
| return sSystemFacade; |
| } |
| |
| public synchronized static DownloadNotifier getDownloadNotifier(Context context) { |
| if (sNotifier == null) { |
| sNotifier = new DownloadNotifier(context); |
| } |
| return sNotifier; |
| } |
| |
| public static String getString(Cursor cursor, String col) { |
| return cursor.getString(cursor.getColumnIndexOrThrow(col)); |
| } |
| |
| public static int getInt(Cursor cursor, String col) { |
| return cursor.getInt(cursor.getColumnIndexOrThrow(col)); |
| } |
| |
| public static void scheduleJob(Context context, long downloadId) { |
| final boolean scheduled = scheduleJob(context, |
| DownloadInfo.queryDownloadInfo(context, downloadId)); |
| if (!scheduled) { |
| // If we didn't schedule a future job, kick off a notification |
| // update pass immediately |
| getDownloadNotifier(context).update(); |
| } |
| } |
| |
| /** |
| * Schedule (or reschedule) a job for the given {@link DownloadInfo} using |
| * its current state to define job constraints. |
| */ |
| public static boolean scheduleJob(Context context, DownloadInfo info) { |
| if (info == null) return false; |
| |
| final JobScheduler scheduler = context.getSystemService(JobScheduler.class); |
| |
| // Tear down any existing job for this download |
| final int jobId = (int) info.mId; |
| scheduler.cancel(jobId); |
| |
| // Skip scheduling if download is paused or finished |
| if (!info.isReadyToSchedule()) return false; |
| |
| final JobInfo.Builder builder = new JobInfo.Builder(jobId, |
| new ComponentName(context, DownloadJobService.class)); |
| |
| // When this download will show a notification, run with a higher |
| // priority, since it's effectively a foreground service |
| if (info.isVisible()) { |
| builder.setPriority(JobInfo.PRIORITY_FOREGROUND_APP); |
| builder.setFlags(JobInfo.FLAG_WILL_BE_FOREGROUND); |
| } |
| |
| // We might have a backoff constraint due to errors |
| final long latency = info.getMinimumLatency(); |
| if (latency > 0) { |
| builder.setMinimumLatency(latency); |
| } |
| |
| // We always require a network, but the type of network might be further |
| // restricted based on download request or user override |
| builder.setRequiredNetworkType(info.getRequiredNetworkType(info.mTotalBytes)); |
| |
| if ((info.mFlags & FLAG_REQUIRES_CHARGING) != 0) { |
| builder.setRequiresCharging(true); |
| } |
| if ((info.mFlags & FLAG_REQUIRES_DEVICE_IDLE) != 0) { |
| builder.setRequiresDeviceIdle(true); |
| } |
| |
| // Provide estimated network size, when possible |
| if (info.mTotalBytes > 0) { |
| if (info.mCurrentBytes > 0 && !TextUtils.isEmpty(info.mETag)) { |
| // If we're resuming an in-progress download, we only need to |
| // download the remaining bytes. |
| builder.setEstimatedNetworkBytes(info.mTotalBytes - info.mCurrentBytes); |
| } else { |
| builder.setEstimatedNetworkBytes(info.mTotalBytes); |
| } |
| } |
| |
| // If package name was filtered during insert (probably due to being |
| // invalid), blame based on the requesting UID instead |
| String packageName = info.mPackage; |
| if (packageName == null) { |
| packageName = context.getPackageManager().getPackagesForUid(info.mUid)[0]; |
| } |
| |
| scheduler.scheduleAsPackage(builder.build(), packageName, UserHandle.myUserId(), TAG); |
| return true; |
| } |
| |
| /* |
| * 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 info about a download. |
| * This file will be touched to reserve it. |
| */ |
| static String generateSaveFile(Context context, String url, String hint, |
| String contentDisposition, String contentLocation, String mimeType, int destination) |
| throws IOException { |
| |
| final File parent; |
| final File[] parentTest; |
| String name = null; |
| |
| if (destination == Downloads.Impl.DESTINATION_FILE_URI) { |
| final File file = new File(Uri.parse(hint).getPath()); |
| parent = file.getParentFile().getAbsoluteFile(); |
| parentTest = new File[] { parent }; |
| name = file.getName(); |
| } else { |
| parent = getRunningDestinationDirectory(context, destination); |
| parentTest = new File[] { |
| parent, |
| getSuccessDestinationDirectory(context, destination) |
| }; |
| name = chooseFilename(url, hint, contentDisposition, contentLocation); |
| } |
| |
| // Ensure target directories are ready |
| for (File test : parentTest) { |
| if (!(test.isDirectory() || test.mkdirs())) { |
| throw new IOException("Failed to create parent for " + test); |
| } |
| } |
| |
| if (DownloadDrmHelper.isDrmConvertNeeded(mimeType)) { |
| name = DownloadDrmHelper.modifyDrmFwLockFileExtension(name); |
| } |
| |
| final String prefix; |
| final String suffix; |
| final int dotIndex = name.lastIndexOf('.'); |
| final boolean missingExtension = dotIndex < 0; |
| if (destination == Downloads.Impl.DESTINATION_FILE_URI) { |
| // Destination is explicitly set - do not change the extension |
| if (missingExtension) { |
| prefix = name; |
| suffix = ""; |
| } else { |
| prefix = name.substring(0, dotIndex); |
| suffix = name.substring(dotIndex); |
| } |
| } else { |
| // Split filename between base and extension |
| // Add an extension if filename does not have one |
| if (missingExtension) { |
| prefix = name; |
| suffix = chooseExtensionFromMimeType(mimeType, true); |
| } else { |
| prefix = name.substring(0, dotIndex); |
| suffix = chooseExtensionFromFilename(mimeType, destination, name, dotIndex); |
| } |
| } |
| |
| synchronized (sUniqueLock) { |
| name = generateAvailableFilenameLocked(parentTest, prefix, suffix); |
| |
| // Claim this filename inside lock to prevent other threads from |
| // clobbering us. We're not paranoid enough to use O_EXCL. |
| final File file = new File(parent, name); |
| file.createNewFile(); |
| return file.getAbsolutePath(); |
| } |
| } |
| |
| private static String chooseFilename(String url, String hint, String contentDisposition, |
| String contentLocation) { |
| 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; |
| } |
| |
| // The VFAT file system is assumed as target for downloads. |
| // Replace invalid characters according to the specifications of VFAT. |
| filename = FileUtils.buildValidFatFilename(filename); |
| |
| 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 lastDotIndex) { |
| 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. |
| 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(lastDotIndex); |
| } |
| return extension; |
| } |
| |
| private static boolean isFilenameAvailableLocked(File[] parents, String name) { |
| if (Constants.RECOVERY_DIRECTORY.equalsIgnoreCase(name)) return false; |
| |
| for (File parent : parents) { |
| if (new File(parent, name).exists()) { |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| |
| private static String generateAvailableFilenameLocked( |
| File[] parents, String prefix, String suffix) throws IOException { |
| String name = prefix + suffix; |
| if (isFilenameAvailableLocked(parents, name)) { |
| return name; |
| } |
| |
| /* |
| * 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) { |
| name = prefix + Constants.FILENAME_SEQUENCE_SEPARATOR + sequence + suffix; |
| if (isFilenameAvailableLocked(parents, name)) { |
| return name; |
| } |
| sequence += sRandom.nextInt(magnitude) + 1; |
| } |
| } |
| |
| throw new IOException("Failed to generate an available filename"); |
| } |
| |
| static boolean isFilenameValid(Context context, File file) { |
| return isFilenameValid(context, file, true); |
| } |
| |
| static boolean isFilenameValidInExternal(Context context, File file) { |
| return isFilenameValid(context, file, false); |
| } |
| |
| /** |
| * Test if given file exists in one of the package-specific external storage |
| * directories that are always writable to apps, regardless of storage |
| * permission. |
| */ |
| static boolean isFilenameValidInExternalPackage(Context context, File file, |
| String packageName) { |
| try { |
| if (containsCanonical(buildExternalStorageAppFilesDirs(packageName), file) || |
| containsCanonical(buildExternalStorageAppObbDirs(packageName), file) || |
| containsCanonical(buildExternalStorageAppCacheDirs(packageName), file) || |
| containsCanonical(buildExternalStorageAppMediaDirs(packageName), file)) { |
| return true; |
| } |
| } catch (IOException e) { |
| Log.w(TAG, "Failed to resolve canonical path: " + e); |
| return false; |
| } |
| |
| Log.w(TAG, "Path appears to be invalid: " + file); |
| return false; |
| } |
| |
| /** |
| * Checks whether the filename looks legitimate for security purposes. This |
| * prevents us from opening files that aren't actually downloads. |
| */ |
| static boolean isFilenameValid(Context context, File file, boolean allowInternal) { |
| try { |
| if (allowInternal) { |
| if (containsCanonical(context.getFilesDir(), file) |
| || containsCanonical(context.getCacheDir(), file) |
| || containsCanonical(Environment.getDownloadCacheDirectory(), file)) { |
| return true; |
| } |
| } |
| |
| final StorageVolume[] volumes = StorageManager.getVolumeList(UserHandle.myUserId(), |
| StorageManager.FLAG_FOR_WRITE); |
| for (StorageVolume volume : volumes) { |
| if (containsCanonical(volume.getPathFile(), file)) { |
| return true; |
| } |
| } |
| } catch (IOException e) { |
| Log.w(TAG, "Failed to resolve canonical path: " + e); |
| return false; |
| } |
| |
| Log.w(TAG, "Path appears to be invalid: " + file); |
| return false; |
| } |
| |
| private static boolean containsCanonical(File dir, File file) throws IOException { |
| return FileUtils.contains(dir.getCanonicalFile(), file); |
| } |
| |
| private static boolean containsCanonical(File[] dirs, File file) throws IOException { |
| for (File dir : dirs) { |
| if (containsCanonical(dir, file)) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| public static File getRunningDestinationDirectory(Context context, int destination) |
| throws IOException { |
| return getDestinationDirectory(context, destination, true); |
| } |
| |
| public static File getSuccessDestinationDirectory(Context context, int destination) |
| throws IOException { |
| return getDestinationDirectory(context, destination, false); |
| } |
| |
| private static File getDestinationDirectory(Context context, int destination, boolean running) |
| throws IOException { |
| switch (destination) { |
| case Downloads.Impl.DESTINATION_CACHE_PARTITION: |
| case Downloads.Impl.DESTINATION_CACHE_PARTITION_PURGEABLE: |
| case Downloads.Impl.DESTINATION_CACHE_PARTITION_NOROAMING: |
| if (running) { |
| return context.getFilesDir(); |
| } else { |
| return context.getCacheDir(); |
| } |
| |
| case Downloads.Impl.DESTINATION_EXTERNAL: |
| final File target = new File( |
| Environment.getExternalStorageDirectory(), Environment.DIRECTORY_DOWNLOADS); |
| if (!target.isDirectory() && target.mkdirs()) { |
| throw new IOException("unable to create external downloads directory"); |
| } |
| return target; |
| |
| default: |
| throw new IllegalStateException("unexpected destination: " + destination); |
| } |
| } |
| |
| /** |
| * Checks whether this looks like a legitimate selection parameter |
| */ |
| public static void validateSelection(String selection, Set<String> allowedColumns) { |
| try { |
| if (selection == null || selection.isEmpty()) { |
| 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 (false) { |
| 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: " + word); |
| } |
| |
| // 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: " + chars[mOffset]); |
| } |
| |
| 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'); |
| } |
| } |
| } |