diff options
Diffstat (limited to 'mobile/android/thirdparty/com/jakewharton/disklrucache/DiskLruCache.java')
| -rw-r--r-- | mobile/android/thirdparty/com/jakewharton/disklrucache/DiskLruCache.java | 943 |
1 files changed, 943 insertions, 0 deletions
diff --git a/mobile/android/thirdparty/com/jakewharton/disklrucache/DiskLruCache.java b/mobile/android/thirdparty/com/jakewharton/disklrucache/DiskLruCache.java new file mode 100644 index 000000000..e81e7fbcc --- /dev/null +++ b/mobile/android/thirdparty/com/jakewharton/disklrucache/DiskLruCache.java @@ -0,0 +1,943 @@ +/* + * Copyright (C) 2011 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.jakewharton.disklrucache; + +import java.io.BufferedWriter; +import java.io.Closeable; +import java.io.EOFException; +import java.io.File; +import java.io.FileInputStream; +import java.io.FileNotFoundException; +import java.io.FileOutputStream; +import java.io.FilterOutputStream; +import java.io.IOException; +import java.io.InputStream; +import java.io.InputStreamReader; +import java.io.OutputStream; +import java.io.OutputStreamWriter; +import java.io.Writer; +import java.util.ArrayList; +import java.util.Iterator; +import java.util.LinkedHashMap; +import java.util.Map; +import java.util.concurrent.Callable; +import java.util.concurrent.LinkedBlockingQueue; +import java.util.concurrent.ThreadPoolExecutor; +import java.util.concurrent.TimeUnit; +import java.util.regex.Matcher; +import java.util.regex.Pattern; + +/** + * A cache that uses a bounded amount of space on a filesystem. Each cache + * entry has a string key and a fixed number of values. Each key must match + * the regex <strong>[a-z0-9_-]{1,120}</strong>. Values are byte sequences, + * accessible as streams or files. Each value must be between {@code 0} and + * {@code Integer.MAX_VALUE} bytes in length. + * + * <p>The cache stores its data in a directory on the filesystem. This + * directory must be exclusive to the cache; the cache may delete or overwrite + * files from its directory. It is an error for multiple processes to use the + * same cache directory at the same time. + * + * <p>This cache limits the number of bytes that it will store on the + * filesystem. When the number of stored bytes exceeds the limit, the cache will + * remove entries in the background until the limit is satisfied. The limit is + * not strict: the cache may temporarily exceed it while waiting for files to be + * deleted. The limit does not include filesystem overhead or the cache + * journal so space-sensitive applications should set a conservative limit. + * + * <p>Clients call {@link #edit} to create or update the values of an entry. An + * entry may have only one editor at one time; if a value is not available to be + * edited then {@link #edit} will return null. + * <ul> + * <li>When an entry is being <strong>created</strong> it is necessary to + * supply a full set of values; the empty value should be used as a + * placeholder if necessary. + * <li>When an entry is being <strong>edited</strong>, it is not necessary + * to supply data for every value; values default to their previous + * value. + * </ul> + * Every {@link #edit} call must be matched by a call to {@link Editor#commit} + * or {@link Editor#abort}. Committing is atomic: a read observes the full set + * of values as they were before or after the commit, but never a mix of values. + * + * <p>Clients call {@link #get} to read a snapshot of an entry. The read will + * observe the value at the time that {@link #get} was called. Updates and + * removals after the call do not impact ongoing reads. + * + * <p>This class is tolerant of some I/O errors. If files are missing from the + * filesystem, the corresponding entries will be dropped from the cache. If + * an error occurs while writing a cache value, the edit will fail silently. + * Callers should handle other problems by catching {@code IOException} and + * responding appropriately. + */ +public final class DiskLruCache implements Closeable { + static final String JOURNAL_FILE = "journal"; + static final String JOURNAL_FILE_TEMP = "journal.tmp"; + static final String JOURNAL_FILE_BACKUP = "journal.bkp"; + static final String MAGIC = "libcore.io.DiskLruCache"; + static final String VERSION_1 = "1"; + static final long ANY_SEQUENCE_NUMBER = -1; + static final String STRING_KEY_PATTERN = "[a-z0-9_-]{1,120}"; + static final Pattern LEGAL_KEY_PATTERN = Pattern.compile(STRING_KEY_PATTERN); + private static final String CLEAN = "CLEAN"; + private static final String DIRTY = "DIRTY"; + private static final String REMOVE = "REMOVE"; + private static final String READ = "READ"; + + /* + * This cache uses a journal file named "journal". A typical journal file + * looks like this: + * libcore.io.DiskLruCache + * 1 + * 100 + * 2 + * + * CLEAN 3400330d1dfc7f3f7f4b8d4d803dfcf6 832 21054 + * DIRTY 335c4c6028171cfddfbaae1a9c313c52 + * CLEAN 335c4c6028171cfddfbaae1a9c313c52 3934 2342 + * REMOVE 335c4c6028171cfddfbaae1a9c313c52 + * DIRTY 1ab96a171faeeee38496d8b330771a7a + * CLEAN 1ab96a171faeeee38496d8b330771a7a 1600 234 + * READ 335c4c6028171cfddfbaae1a9c313c52 + * READ 3400330d1dfc7f3f7f4b8d4d803dfcf6 + * + * The first five lines of the journal form its header. They are the + * constant string "libcore.io.DiskLruCache", the disk cache's version, + * the application's version, the value count, and a blank line. + * + * Each of the subsequent lines in the file is a record of the state of a + * cache entry. Each line contains space-separated values: a state, a key, + * and optional state-specific values. + * o DIRTY lines track that an entry is actively being created or updated. + * Every successful DIRTY action should be followed by a CLEAN or REMOVE + * action. DIRTY lines without a matching CLEAN or REMOVE indicate that + * temporary files may need to be deleted. + * o CLEAN lines track a cache entry that has been successfully published + * and may be read. A publish line is followed by the lengths of each of + * its values. + * o READ lines track accesses for LRU. + * o REMOVE lines track entries that have been deleted. + * + * The journal file is appended to as cache operations occur. The journal may + * occasionally be compacted by dropping redundant lines. A temporary file named + * "journal.tmp" will be used during compaction; that file should be deleted if + * it exists when the cache is opened. + */ + + private final File directory; + private final File journalFile; + private final File journalFileTmp; + private final File journalFileBackup; + private final int appVersion; + private long maxSize; + private final int valueCount; + private long size = 0; + private Writer journalWriter; + private final LinkedHashMap<String, Entry> lruEntries = + new LinkedHashMap<String, Entry>(0, 0.75f, true); + private int redundantOpCount; + + /** + * To differentiate between old and current snapshots, each entry is given + * a sequence number each time an edit is committed. A snapshot is stale if + * its sequence number is not equal to its entry's sequence number. + */ + private long nextSequenceNumber = 0; + + /** This cache uses a single background thread to evict entries. */ + final ThreadPoolExecutor executorService = + new ThreadPoolExecutor(0, 1, 60L, TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>()); + private final Callable<Void> cleanupCallable = new Callable<Void>() { + public Void call() throws Exception { + synchronized (DiskLruCache.this) { + if (journalWriter == null) { + return null; // Closed. + } + trimToSize(); + if (journalRebuildRequired()) { + rebuildJournal(); + redundantOpCount = 0; + } + } + return null; + } + }; + + private DiskLruCache(File directory, int appVersion, int valueCount, long maxSize) { + this.directory = directory; + this.appVersion = appVersion; + this.journalFile = new File(directory, JOURNAL_FILE); + this.journalFileTmp = new File(directory, JOURNAL_FILE_TEMP); + this.journalFileBackup = new File(directory, JOURNAL_FILE_BACKUP); + this.valueCount = valueCount; + this.maxSize = maxSize; + } + + /** + * Opens the cache in {@code directory}, creating a cache if none exists + * there. + * + * @param directory a writable directory + * @param valueCount the number of values per cache entry. Must be positive. + * @param maxSize the maximum number of bytes this cache should use to store + * @throws IOException if reading or writing the cache directory fails + */ + public static DiskLruCache open(File directory, int appVersion, int valueCount, long maxSize) + throws IOException { + if (maxSize <= 0) { + throw new IllegalArgumentException("maxSize <= 0"); + } + if (valueCount <= 0) { + throw new IllegalArgumentException("valueCount <= 0"); + } + + // If a bkp file exists, use it instead. + File backupFile = new File(directory, JOURNAL_FILE_BACKUP); + if (backupFile.exists()) { + File journalFile = new File(directory, JOURNAL_FILE); + // If journal file also exists just delete backup file. + if (journalFile.exists()) { + backupFile.delete(); + } else { + renameTo(backupFile, journalFile, false); + } + } + + // Prefer to pick up where we left off. + DiskLruCache cache = new DiskLruCache(directory, appVersion, valueCount, maxSize); + if (cache.journalFile.exists()) { + try { + cache.readJournal(); + cache.processJournal(); + return cache; + } catch (IOException journalIsCorrupt) { + System.out + .println("DiskLruCache " + + directory + + " is corrupt: " + + journalIsCorrupt.getMessage() + + ", removing"); + cache.delete(); + } + } + + // Create a new empty cache. + directory.mkdirs(); + cache = new DiskLruCache(directory, appVersion, valueCount, maxSize); + cache.rebuildJournal(); + return cache; + } + + private void readJournal() throws IOException { + StrictLineReader reader = new StrictLineReader(new FileInputStream(journalFile), Util.US_ASCII); + try { + String magic = reader.readLine(); + String version = reader.readLine(); + String appVersionString = reader.readLine(); + String valueCountString = reader.readLine(); + String blank = reader.readLine(); + if (!MAGIC.equals(magic) + || !VERSION_1.equals(version) + || !Integer.toString(appVersion).equals(appVersionString) + || !Integer.toString(valueCount).equals(valueCountString) + || !"".equals(blank)) { + throw new IOException("unexpected journal header: [" + magic + ", " + version + ", " + + valueCountString + ", " + blank + "]"); + } + + int lineCount = 0; + while (true) { + try { + readJournalLine(reader.readLine()); + lineCount++; + } catch (EOFException endOfJournal) { + break; + } + } + redundantOpCount = lineCount - lruEntries.size(); + + // If we ended on a truncated line, rebuild the journal before appending to it. + if (reader.hasUnterminatedLine()) { + rebuildJournal(); + } else { + journalWriter = new BufferedWriter(new OutputStreamWriter( + new FileOutputStream(journalFile, true), Util.US_ASCII)); + } + } finally { + Util.closeQuietly(reader); + } + } + + private void readJournalLine(String line) throws IOException { + int firstSpace = line.indexOf(' '); + if (firstSpace == -1) { + throw new IOException("unexpected journal line: " + line); + } + + int keyBegin = firstSpace + 1; + int secondSpace = line.indexOf(' ', keyBegin); + final String key; + if (secondSpace == -1) { + key = line.substring(keyBegin); + if (firstSpace == REMOVE.length() && line.startsWith(REMOVE)) { + lruEntries.remove(key); + return; + } + } else { + key = line.substring(keyBegin, secondSpace); + } + + Entry entry = lruEntries.get(key); + if (entry == null) { + entry = new Entry(key); + lruEntries.put(key, entry); + } + + if (secondSpace != -1 && firstSpace == CLEAN.length() && line.startsWith(CLEAN)) { + String[] parts = line.substring(secondSpace + 1).split(" "); + entry.readable = true; + entry.currentEditor = null; + entry.setLengths(parts); + } else if (secondSpace == -1 && firstSpace == DIRTY.length() && line.startsWith(DIRTY)) { + entry.currentEditor = new Editor(entry); + } else if (secondSpace == -1 && firstSpace == READ.length() && line.startsWith(READ)) { + // This work was already done by calling lruEntries.get(). + } else { + throw new IOException("unexpected journal line: " + line); + } + } + + /** + * Computes the initial size and collects garbage as a part of opening the + * cache. Dirty entries are assumed to be inconsistent and will be deleted. + */ + private void processJournal() throws IOException { + deleteIfExists(journalFileTmp); + for (Iterator<Entry> i = lruEntries.values().iterator(); i.hasNext(); ) { + Entry entry = i.next(); + if (entry.currentEditor == null) { + for (int t = 0; t < valueCount; t++) { + size += entry.lengths[t]; + } + } else { + entry.currentEditor = null; + for (int t = 0; t < valueCount; t++) { + deleteIfExists(entry.getCleanFile(t)); + deleteIfExists(entry.getDirtyFile(t)); + } + i.remove(); + } + } + } + + /** + * Creates a new journal that omits redundant information. This replaces the + * current journal if it exists. + */ + private synchronized void rebuildJournal() throws IOException { + if (journalWriter != null) { + journalWriter.close(); + } + + Writer writer = new BufferedWriter( + new OutputStreamWriter(new FileOutputStream(journalFileTmp), Util.US_ASCII)); + try { + writer.write(MAGIC); + writer.write("\n"); + writer.write(VERSION_1); + writer.write("\n"); + writer.write(Integer.toString(appVersion)); + writer.write("\n"); + writer.write(Integer.toString(valueCount)); + writer.write("\n"); + writer.write("\n"); + + for (Entry entry : lruEntries.values()) { + if (entry.currentEditor != null) { + writer.write(DIRTY + ' ' + entry.key + '\n'); + } else { + writer.write(CLEAN + ' ' + entry.key + entry.getLengths() + '\n'); + } + } + } finally { + writer.close(); + } + + if (journalFile.exists()) { + renameTo(journalFile, journalFileBackup, true); + } + renameTo(journalFileTmp, journalFile, false); + journalFileBackup.delete(); + + journalWriter = new BufferedWriter( + new OutputStreamWriter(new FileOutputStream(journalFile, true), Util.US_ASCII)); + } + + private static void deleteIfExists(File file) throws IOException { + if (file.exists() && !file.delete()) { + throw new IOException(); + } + } + + private static void renameTo(File from, File to, boolean deleteDestination) throws IOException { + if (deleteDestination) { + deleteIfExists(to); + } + if (!from.renameTo(to)) { + throw new IOException(); + } + } + + /** + * Returns a snapshot of the entry named {@code key}, or null if it doesn't + * exist is not currently readable. If a value is returned, it is moved to + * the head of the LRU queue. + */ + public synchronized Snapshot get(String key) throws IOException { + checkNotClosed(); + validateKey(key); + Entry entry = lruEntries.get(key); + if (entry == null) { + return null; + } + + if (!entry.readable) { + return null; + } + + // Open all streams eagerly to guarantee that we see a single published + // snapshot. If we opened streams lazily then the streams could come + // from different edits. + InputStream[] ins = new InputStream[valueCount]; + try { + for (int i = 0; i < valueCount; i++) { + ins[i] = new FileInputStream(entry.getCleanFile(i)); + } + } catch (FileNotFoundException e) { + // A file must have been deleted manually! + for (int i = 0; i < valueCount; i++) { + if (ins[i] != null) { + Util.closeQuietly(ins[i]); + } else { + break; + } + } + return null; + } + + redundantOpCount++; + journalWriter.append(READ + ' ' + key + '\n'); + if (journalRebuildRequired()) { + executorService.submit(cleanupCallable); + } + + return new Snapshot(key, entry.sequenceNumber, ins, entry.lengths); + } + + /** + * Returns an editor for the entry named {@code key}, or null if another + * edit is in progress. + */ + public Editor edit(String key) throws IOException { + return edit(key, ANY_SEQUENCE_NUMBER); + } + + private synchronized Editor edit(String key, long expectedSequenceNumber) throws IOException { + checkNotClosed(); + validateKey(key); + Entry entry = lruEntries.get(key); + if (expectedSequenceNumber != ANY_SEQUENCE_NUMBER && (entry == null + || entry.sequenceNumber != expectedSequenceNumber)) { + return null; // Snapshot is stale. + } + if (entry == null) { + entry = new Entry(key); + lruEntries.put(key, entry); + } else if (entry.currentEditor != null) { + return null; // Another edit is in progress. + } + + Editor editor = new Editor(entry); + entry.currentEditor = editor; + + // Flush the journal before creating files to prevent file leaks. + journalWriter.write(DIRTY + ' ' + key + '\n'); + journalWriter.flush(); + return editor; + } + + /** Returns the directory where this cache stores its data. */ + public File getDirectory() { + return directory; + } + + /** + * Returns the maximum number of bytes that this cache should use to store + * its data. + */ + public synchronized long getMaxSize() { + return maxSize; + } + + /** + * Changes the maximum number of bytes the cache can store and queues a job + * to trim the existing store, if necessary. + */ + public synchronized void setMaxSize(long maxSize) { + this.maxSize = maxSize; + executorService.submit(cleanupCallable); + } + + /** + * Returns the number of bytes currently being used to store the values in + * this cache. This may be greater than the max size if a background + * deletion is pending. + */ + public synchronized long size() { + return size; + } + + private synchronized void completeEdit(Editor editor, boolean success) throws IOException { + Entry entry = editor.entry; + if (entry.currentEditor != editor) { + throw new IllegalStateException(); + } + + // If this edit is creating the entry for the first time, every index must have a value. + if (success && !entry.readable) { + for (int i = 0; i < valueCount; i++) { + if (!editor.written[i]) { + editor.abort(); + throw new IllegalStateException("Newly created entry didn't create value for index " + i); + } + if (!entry.getDirtyFile(i).exists()) { + editor.abort(); + return; + } + } + } + + for (int i = 0; i < valueCount; i++) { + File dirty = entry.getDirtyFile(i); + if (success) { + if (dirty.exists()) { + File clean = entry.getCleanFile(i); + dirty.renameTo(clean); + long oldLength = entry.lengths[i]; + long newLength = clean.length(); + entry.lengths[i] = newLength; + size = size - oldLength + newLength; + } + } else { + deleteIfExists(dirty); + } + } + + redundantOpCount++; + entry.currentEditor = null; + if (entry.readable | success) { + entry.readable = true; + journalWriter.write(CLEAN + ' ' + entry.key + entry.getLengths() + '\n'); + if (success) { + entry.sequenceNumber = nextSequenceNumber++; + } + } else { + lruEntries.remove(entry.key); + journalWriter.write(REMOVE + ' ' + entry.key + '\n'); + } + journalWriter.flush(); + + if (size > maxSize || journalRebuildRequired()) { + executorService.submit(cleanupCallable); + } + } + + /** + * We only rebuild the journal when it will halve the size of the journal + * and eliminate at least 2000 ops. + */ + private boolean journalRebuildRequired() { + final int redundantOpCompactThreshold = 2000; + return redundantOpCount >= redundantOpCompactThreshold // + && redundantOpCount >= lruEntries.size(); + } + + /** + * Drops the entry for {@code key} if it exists and can be removed. Entries + * actively being edited cannot be removed. + * + * @return true if an entry was removed. + */ + public synchronized boolean remove(String key) throws IOException { + checkNotClosed(); + validateKey(key); + Entry entry = lruEntries.get(key); + if (entry == null || entry.currentEditor != null) { + return false; + } + + for (int i = 0; i < valueCount; i++) { + File file = entry.getCleanFile(i); + if (file.exists() && !file.delete()) { + throw new IOException("failed to delete " + file); + } + size -= entry.lengths[i]; + entry.lengths[i] = 0; + } + + redundantOpCount++; + journalWriter.append(REMOVE + ' ' + key + '\n'); + lruEntries.remove(key); + + if (journalRebuildRequired()) { + executorService.submit(cleanupCallable); + } + + return true; + } + + /** Returns true if this cache has been closed. */ + public synchronized boolean isClosed() { + return journalWriter == null; + } + + private void checkNotClosed() { + if (journalWriter == null) { + throw new IllegalStateException("cache is closed"); + } + } + + /** Force buffered operations to the filesystem. */ + public synchronized void flush() throws IOException { + checkNotClosed(); + trimToSize(); + journalWriter.flush(); + } + + /** Closes this cache. Stored values will remain on the filesystem. */ + public synchronized void close() throws IOException { + if (journalWriter == null) { + return; // Already closed. + } + for (Entry entry : new ArrayList<Entry>(lruEntries.values())) { + if (entry.currentEditor != null) { + entry.currentEditor.abort(); + } + } + trimToSize(); + journalWriter.close(); + journalWriter = null; + } + + private void trimToSize() throws IOException { + while (size > maxSize) { + Map.Entry<String, Entry> toEvict = lruEntries.entrySet().iterator().next(); + remove(toEvict.getKey()); + } + } + + /** + * Closes the cache and deletes all of its stored values. This will delete + * all files in the cache directory including files that weren't created by + * the cache. + */ + public void delete() throws IOException { + close(); + Util.deleteContents(directory); + } + + private void validateKey(String key) { + Matcher matcher = LEGAL_KEY_PATTERN.matcher(key); + if (!matcher.matches()) { + throw new IllegalArgumentException("keys must match regex " + + STRING_KEY_PATTERN + ": \"" + key + "\""); + } + } + + private static String inputStreamToString(InputStream in) throws IOException { + return Util.readFully(new InputStreamReader(in, Util.UTF_8)); + } + + /** A snapshot of the values for an entry. */ + public final class Snapshot implements Closeable { + private final String key; + private final long sequenceNumber; + private final InputStream[] ins; + private final long[] lengths; + + private Snapshot(String key, long sequenceNumber, InputStream[] ins, long[] lengths) { + this.key = key; + this.sequenceNumber = sequenceNumber; + this.ins = ins; + this.lengths = lengths; + } + + /** + * Returns an editor for this snapshot's entry, or null if either the + * entry has changed since this snapshot was created or if another edit + * is in progress. + */ + public Editor edit() throws IOException { + return DiskLruCache.this.edit(key, sequenceNumber); + } + + /** Returns the unbuffered stream with the value for {@code index}. */ + public InputStream getInputStream(int index) { + return ins[index]; + } + + /** Returns the string value for {@code index}. */ + public String getString(int index) throws IOException { + return inputStreamToString(getInputStream(index)); + } + + /** Returns the byte length of the value for {@code index}. */ + public long getLength(int index) { + return lengths[index]; + } + + public void close() { + for (InputStream in : ins) { + Util.closeQuietly(in); + } + } + } + + private static final OutputStream NULL_OUTPUT_STREAM = new OutputStream() { + @Override + public void write(int b) throws IOException { + // Eat all writes silently. Nom nom. + } + }; + + /** Edits the values for an entry. */ + public final class Editor { + private final Entry entry; + private final boolean[] written; + private boolean hasErrors; + private boolean committed; + + private Editor(Entry entry) { + this.entry = entry; + this.written = (entry.readable) ? null : new boolean[valueCount]; + } + + /** + * Returns an unbuffered input stream to read the last committed value, + * or null if no value has been committed. + */ + public InputStream newInputStream(int index) throws IOException { + synchronized (DiskLruCache.this) { + if (entry.currentEditor != this) { + throw new IllegalStateException(); + } + if (!entry.readable) { + return null; + } + try { + return new FileInputStream(entry.getCleanFile(index)); + } catch (FileNotFoundException e) { + return null; + } + } + } + + /** + * Returns the last committed value as a string, or null if no value + * has been committed. + */ + public String getString(int index) throws IOException { + InputStream in = newInputStream(index); + return in != null ? inputStreamToString(in) : null; + } + + /** + * Returns a new unbuffered output stream to write the value at + * {@code index}. If the underlying output stream encounters errors + * when writing to the filesystem, this edit will be aborted when + * {@link #commit} is called. The returned output stream does not throw + * IOExceptions. + */ + public OutputStream newOutputStream(int index) throws IOException { + if (index < 0 || index >= valueCount) { + throw new IllegalArgumentException("Expected index " + index + " to " + + "be greater than 0 and less than the maximum value count " + + "of " + valueCount); + } + synchronized (DiskLruCache.this) { + if (entry.currentEditor != this) { + throw new IllegalStateException(); + } + if (!entry.readable) { + written[index] = true; + } + File dirtyFile = entry.getDirtyFile(index); + FileOutputStream outputStream; + try { + outputStream = new FileOutputStream(dirtyFile); + } catch (FileNotFoundException e) { + // Attempt to recreate the cache directory. + directory.mkdirs(); + try { + outputStream = new FileOutputStream(dirtyFile); + } catch (FileNotFoundException e2) { + // We are unable to recover. Silently eat the writes. + return NULL_OUTPUT_STREAM; + } + } + return new FaultHidingOutputStream(outputStream); + } + } + + /** Sets the value at {@code index} to {@code value}. */ + public void set(int index, String value) throws IOException { + Writer writer = null; + try { + writer = new OutputStreamWriter(newOutputStream(index), Util.UTF_8); + writer.write(value); + } finally { + Util.closeQuietly(writer); + } + } + + /** + * Commits this edit so it is visible to readers. This releases the + * edit lock so another edit may be started on the same key. + */ + public void commit() throws IOException { + if (hasErrors) { + completeEdit(this, false); + remove(entry.key); // The previous entry is stale. + } else { + completeEdit(this, true); + } + committed = true; + } + + /** + * Aborts this edit. This releases the edit lock so another edit may be + * started on the same key. + */ + public void abort() throws IOException { + completeEdit(this, false); + } + + public void abortUnlessCommitted() { + if (!committed) { + try { + abort(); + } catch (IOException ignored) { + } + } + } + + private class FaultHidingOutputStream extends FilterOutputStream { + private FaultHidingOutputStream(OutputStream out) { + super(out); + } + + @Override public void write(int oneByte) { + try { + out.write(oneByte); + } catch (IOException e) { + hasErrors = true; + } + } + + @Override public void write(byte[] buffer, int offset, int length) { + try { + out.write(buffer, offset, length); + } catch (IOException e) { + hasErrors = true; + } + } + + @Override public void close() { + try { + out.close(); + } catch (IOException e) { + hasErrors = true; + } + } + + @Override public void flush() { + try { + out.flush(); + } catch (IOException e) { + hasErrors = true; + } + } + } + } + + private final class Entry { + private final String key; + + /** Lengths of this entry's files. */ + private final long[] lengths; + + /** True if this entry has ever been published. */ + private boolean readable; + + /** The ongoing edit or null if this entry is not being edited. */ + private Editor currentEditor; + + /** The sequence number of the most recently committed edit to this entry. */ + private long sequenceNumber; + + private Entry(String key) { + this.key = key; + this.lengths = new long[valueCount]; + } + + public String getLengths() throws IOException { + StringBuilder result = new StringBuilder(); + for (long size : lengths) { + result.append(' ').append(size); + } + return result.toString(); + } + + /** Set lengths using decimal numbers like "10123". */ + private void setLengths(String[] strings) throws IOException { + if (strings.length != valueCount) { + throw invalidLengths(strings); + } + + try { + for (int i = 0; i < strings.length; i++) { + lengths[i] = Long.parseLong(strings[i]); + } + } catch (NumberFormatException e) { + throw invalidLengths(strings); + } + } + + private IOException invalidLengths(String[] strings) throws IOException { + throw new IOException("unexpected journal line: " + java.util.Arrays.toString(strings)); + } + + public File getCleanFile(int i) { + return new File(directory, key + "." + i); + } + + public File getDirtyFile(int i) { + return new File(directory, key + "." + i + ".tmp"); + } + } +} |