diff options
Diffstat (limited to 'src/main/java/com/android/volley/toolbox/DiskBasedCache.java')
| -rw-r--r-- | src/main/java/com/android/volley/toolbox/DiskBasedCache.java | 677 |
1 files changed, 0 insertions, 677 deletions
diff --git a/src/main/java/com/android/volley/toolbox/DiskBasedCache.java b/src/main/java/com/android/volley/toolbox/DiskBasedCache.java deleted file mode 100644 index d4310e0..0000000 --- a/src/main/java/com/android/volley/toolbox/DiskBasedCache.java +++ /dev/null @@ -1,677 +0,0 @@ -/* - * 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.android.volley.toolbox; - -import android.os.SystemClock; -import android.text.TextUtils; -import androidx.annotation.VisibleForTesting; -import com.android.volley.Cache; -import com.android.volley.Header; -import com.android.volley.VolleyLog; -import java.io.BufferedInputStream; -import java.io.BufferedOutputStream; -import java.io.DataInputStream; -import java.io.EOFException; -import java.io.File; -import java.io.FileInputStream; -import java.io.FileNotFoundException; -import java.io.FileOutputStream; -import java.io.FilterInputStream; -import java.io.IOException; -import java.io.InputStream; -import java.io.OutputStream; -import java.util.ArrayList; -import java.util.Collections; -import java.util.Iterator; -import java.util.LinkedHashMap; -import java.util.List; -import java.util.Map; - -/** - * Cache implementation that caches files directly onto the hard disk in the specified directory. - * The default disk usage size is 5MB, but is configurable. - * - * <p>This cache supports the {@link Entry#allResponseHeaders} headers field. - */ -public class DiskBasedCache implements Cache { - - /** Map of the Key, CacheHeader pairs */ - private final Map<String, CacheHeader> mEntries = new LinkedHashMap<>(16, .75f, true); - - /** Total amount of space currently used by the cache in bytes. */ - private long mTotalSize = 0; - - /** The supplier for the root directory to use for the cache. */ - private final FileSupplier mRootDirectorySupplier; - - /** The maximum size of the cache in bytes. */ - private final int mMaxCacheSizeInBytes; - - /** Default maximum disk usage in bytes. */ - private static final int DEFAULT_DISK_USAGE_BYTES = 5 * 1024 * 1024; - - /** High water mark percentage for the cache */ - @VisibleForTesting static final float HYSTERESIS_FACTOR = 0.9f; - - /** Magic number for current version of cache file format. */ - private static final int CACHE_MAGIC = 0x20150306; - - /** - * Constructs an instance of the DiskBasedCache at the specified directory. - * - * @param rootDirectory The root directory of the cache. - * @param maxCacheSizeInBytes The maximum size of the cache in bytes. Note that the cache may - * briefly exceed this size on disk when writing a new entry that pushes it over the limit - * until the ensuing pruning completes. - */ - public DiskBasedCache(final File rootDirectory, int maxCacheSizeInBytes) { - mRootDirectorySupplier = - new FileSupplier() { - @Override - public File get() { - return rootDirectory; - } - }; - mMaxCacheSizeInBytes = maxCacheSizeInBytes; - } - - /** - * Constructs an instance of the DiskBasedCache at the specified directory. - * - * @param rootDirectorySupplier The supplier for the root directory of the cache. - * @param maxCacheSizeInBytes The maximum size of the cache in bytes. Note that the cache may - * briefly exceed this size on disk when writing a new entry that pushes it over the limit - * until the ensuing pruning completes. - */ - public DiskBasedCache(FileSupplier rootDirectorySupplier, int maxCacheSizeInBytes) { - mRootDirectorySupplier = rootDirectorySupplier; - mMaxCacheSizeInBytes = maxCacheSizeInBytes; - } - - /** - * Constructs an instance of the DiskBasedCache at the specified directory using the default - * maximum cache size of 5MB. - * - * @param rootDirectory The root directory of the cache. - */ - public DiskBasedCache(File rootDirectory) { - this(rootDirectory, DEFAULT_DISK_USAGE_BYTES); - } - - /** - * Constructs an instance of the DiskBasedCache at the specified directory using the default - * maximum cache size of 5MB. - * - * @param rootDirectorySupplier The supplier for the root directory of the cache. - */ - public DiskBasedCache(FileSupplier rootDirectorySupplier) { - this(rootDirectorySupplier, DEFAULT_DISK_USAGE_BYTES); - } - - /** Clears the cache. Deletes all cached files from disk. */ - @Override - public synchronized void clear() { - File[] files = mRootDirectorySupplier.get().listFiles(); - if (files != null) { - for (File file : files) { - file.delete(); - } - } - mEntries.clear(); - mTotalSize = 0; - VolleyLog.d("Cache cleared."); - } - - /** Returns the cache entry with the specified key if it exists, null otherwise. */ - @Override - public synchronized Entry get(String key) { - CacheHeader entry = mEntries.get(key); - // if the entry does not exist, return. - if (entry == null) { - return null; - } - File file = getFileForKey(key); - try { - CountingInputStream cis = - new CountingInputStream( - new BufferedInputStream(createInputStream(file)), file.length()); - try { - CacheHeader entryOnDisk = CacheHeader.readHeader(cis); - if (!TextUtils.equals(key, entryOnDisk.key)) { - // File was shared by two keys and now holds data for a different entry! - VolleyLog.d( - "%s: key=%s, found=%s", file.getAbsolutePath(), key, entryOnDisk.key); - // Remove key whose contents on disk have been replaced. - removeEntry(key); - return null; - } - byte[] data = streamToBytes(cis, cis.bytesRemaining()); - return entry.toCacheEntry(data); - } finally { - // Any IOException thrown here is handled by the below catch block by design. - //noinspection ThrowFromFinallyBlock - cis.close(); - } - } catch (IOException e) { - VolleyLog.d("%s: %s", file.getAbsolutePath(), e.toString()); - remove(key); - return null; - } - } - - /** - * Initializes the DiskBasedCache by scanning for all files currently in the specified root - * directory. Creates the root directory if necessary. - */ - @Override - public synchronized void initialize() { - File rootDirectory = mRootDirectorySupplier.get(); - if (!rootDirectory.exists()) { - if (!rootDirectory.mkdirs()) { - VolleyLog.e("Unable to create cache dir %s", rootDirectory.getAbsolutePath()); - } - return; - } - File[] files = rootDirectory.listFiles(); - if (files == null) { - return; - } - for (File file : files) { - try { - long entrySize = file.length(); - CountingInputStream cis = - new CountingInputStream( - new BufferedInputStream(createInputStream(file)), entrySize); - try { - CacheHeader entry = CacheHeader.readHeader(cis); - entry.size = entrySize; - putEntry(entry.key, entry); - } finally { - // Any IOException thrown here is handled by the below catch block by design. - //noinspection ThrowFromFinallyBlock - cis.close(); - } - } catch (IOException e) { - //noinspection ResultOfMethodCallIgnored - file.delete(); - } - } - } - - /** - * Invalidates an entry in the cache. - * - * @param key Cache key - * @param fullExpire True to fully expire the entry, false to soft expire - */ - @Override - public synchronized void invalidate(String key, boolean fullExpire) { - Entry entry = get(key); - if (entry != null) { - entry.softTtl = 0; - if (fullExpire) { - entry.ttl = 0; - } - put(key, entry); - } - } - - /** Puts the entry with the specified key into the cache. */ - @Override - public synchronized void put(String key, Entry entry) { - // If adding this entry would trigger a prune, but pruning would cause the new entry to be - // deleted, then skip writing the entry in the first place, as this is just churn. - // Note that we don't include the cache header overhead in this calculation for simplicity, - // so putting entries which are just below the threshold may still cause this churn. - if (mTotalSize + entry.data.length > mMaxCacheSizeInBytes - && entry.data.length > mMaxCacheSizeInBytes * HYSTERESIS_FACTOR) { - return; - } - File file = getFileForKey(key); - try { - BufferedOutputStream fos = new BufferedOutputStream(createOutputStream(file)); - CacheHeader e = new CacheHeader(key, entry); - boolean success = e.writeHeader(fos); - if (!success) { - fos.close(); - VolleyLog.d("Failed to write header for %s", file.getAbsolutePath()); - throw new IOException(); - } - fos.write(entry.data); - fos.close(); - e.size = file.length(); - putEntry(key, e); - pruneIfNeeded(); - } catch (IOException e) { - boolean deleted = file.delete(); - if (!deleted) { - VolleyLog.d("Could not clean up file %s", file.getAbsolutePath()); - } - initializeIfRootDirectoryDeleted(); - } - } - - /** Removes the specified key from the cache if it exists. */ - @Override - public synchronized void remove(String key) { - boolean deleted = getFileForKey(key).delete(); - removeEntry(key); - if (!deleted) { - VolleyLog.d( - "Could not delete cache entry for key=%s, filename=%s", - key, getFilenameForKey(key)); - } - } - - /** - * Creates a pseudo-unique filename for the specified cache key. - * - * @param key The key to generate a file name for. - * @return A pseudo-unique filename. - */ - private String getFilenameForKey(String key) { - int firstHalfLength = key.length() / 2; - String localFilename = String.valueOf(key.substring(0, firstHalfLength).hashCode()); - localFilename += String.valueOf(key.substring(firstHalfLength).hashCode()); - return localFilename; - } - - /** Returns a file object for the given cache key. */ - public File getFileForKey(String key) { - return new File(mRootDirectorySupplier.get(), getFilenameForKey(key)); - } - - /** Re-initialize the cache if the directory was deleted. */ - private void initializeIfRootDirectoryDeleted() { - if (!mRootDirectorySupplier.get().exists()) { - VolleyLog.d("Re-initializing cache after external clearing."); - mEntries.clear(); - mTotalSize = 0; - initialize(); - } - } - - /** Represents a supplier for {@link File}s. */ - public interface FileSupplier { - File get(); - } - - /** Prunes the cache to fit the maximum size. */ - private void pruneIfNeeded() { - if (mTotalSize < mMaxCacheSizeInBytes) { - return; - } - if (VolleyLog.DEBUG) { - VolleyLog.v("Pruning old cache entries."); - } - - long before = mTotalSize; - int prunedFiles = 0; - long startTime = SystemClock.elapsedRealtime(); - - Iterator<Map.Entry<String, CacheHeader>> iterator = mEntries.entrySet().iterator(); - while (iterator.hasNext()) { - Map.Entry<String, CacheHeader> entry = iterator.next(); - CacheHeader e = entry.getValue(); - boolean deleted = getFileForKey(e.key).delete(); - if (deleted) { - mTotalSize -= e.size; - } else { - VolleyLog.d( - "Could not delete cache entry for key=%s, filename=%s", - e.key, getFilenameForKey(e.key)); - } - iterator.remove(); - prunedFiles++; - - if (mTotalSize < mMaxCacheSizeInBytes * HYSTERESIS_FACTOR) { - break; - } - } - - if (VolleyLog.DEBUG) { - VolleyLog.v( - "pruned %d files, %d bytes, %d ms", - prunedFiles, (mTotalSize - before), SystemClock.elapsedRealtime() - startTime); - } - } - - /** - * Puts the entry with the specified key into the cache. - * - * @param key The key to identify the entry by. - * @param entry The entry to cache. - */ - private void putEntry(String key, CacheHeader entry) { - if (!mEntries.containsKey(key)) { - mTotalSize += entry.size; - } else { - CacheHeader oldEntry = mEntries.get(key); - mTotalSize += (entry.size - oldEntry.size); - } - mEntries.put(key, entry); - } - - /** Removes the entry identified by 'key' from the cache. */ - private void removeEntry(String key) { - CacheHeader removed = mEntries.remove(key); - if (removed != null) { - mTotalSize -= removed.size; - } - } - - /** - * Reads length bytes from CountingInputStream into byte array. - * - * @param cis input stream - * @param length number of bytes to read - * @throws IOException if fails to read all bytes - */ - @VisibleForTesting - static byte[] streamToBytes(CountingInputStream cis, long length) throws IOException { - long maxLength = cis.bytesRemaining(); - // Length cannot be negative or greater than bytes remaining, and must not overflow int. - if (length < 0 || length > maxLength || (int) length != length) { - throw new IOException("streamToBytes length=" + length + ", maxLength=" + maxLength); - } - byte[] bytes = new byte[(int) length]; - new DataInputStream(cis).readFully(bytes); - return bytes; - } - - @VisibleForTesting - InputStream createInputStream(File file) throws FileNotFoundException { - return new FileInputStream(file); - } - - @VisibleForTesting - OutputStream createOutputStream(File file) throws FileNotFoundException { - return new FileOutputStream(file); - } - - /** Handles holding onto the cache headers for an entry. */ - @VisibleForTesting - static class CacheHeader { - /** - * The size of the data identified by this CacheHeader on disk (both header and data). - * - * <p>Must be set by the caller after it has been calculated. - * - * <p>This is not serialized to disk. - */ - long size; - - /** The key that identifies the cache entry. */ - final String key; - - /** ETag for cache coherence. */ - final String etag; - - /** Date of this response as reported by the server. */ - final long serverDate; - - /** The last modified date for the requested object. */ - final long lastModified; - - /** TTL for this record. */ - final long ttl; - - /** Soft TTL for this record. */ - final long softTtl; - - /** Headers from the response resulting in this cache entry. */ - final List<Header> allResponseHeaders; - - private CacheHeader( - String key, - String etag, - long serverDate, - long lastModified, - long ttl, - long softTtl, - List<Header> allResponseHeaders) { - this.key = key; - this.etag = "".equals(etag) ? null : etag; - this.serverDate = serverDate; - this.lastModified = lastModified; - this.ttl = ttl; - this.softTtl = softTtl; - this.allResponseHeaders = allResponseHeaders; - } - - /** - * Instantiates a new CacheHeader object. - * - * @param key The key that identifies the cache entry - * @param entry The cache entry. - */ - CacheHeader(String key, Entry entry) { - this( - key, - entry.etag, - entry.serverDate, - entry.lastModified, - entry.ttl, - entry.softTtl, - getAllResponseHeaders(entry)); - } - - private static List<Header> getAllResponseHeaders(Entry entry) { - // If the entry contains all the response headers, use that field directly. - if (entry.allResponseHeaders != null) { - return entry.allResponseHeaders; - } - - // Legacy fallback - copy headers from the map. - return HttpHeaderParser.toAllHeaderList(entry.responseHeaders); - } - - /** - * Reads the header from a CountingInputStream and returns a CacheHeader object. - * - * @param is The InputStream to read from. - * @throws IOException if fails to read header - */ - static CacheHeader readHeader(CountingInputStream is) throws IOException { - int magic = readInt(is); - if (magic != CACHE_MAGIC) { - // don't bother deleting, it'll get pruned eventually - throw new IOException(); - } - String key = readString(is); - String etag = readString(is); - long serverDate = readLong(is); - long lastModified = readLong(is); - long ttl = readLong(is); - long softTtl = readLong(is); - List<Header> allResponseHeaders = readHeaderList(is); - return new CacheHeader( - key, etag, serverDate, lastModified, ttl, softTtl, allResponseHeaders); - } - - /** Creates a cache entry for the specified data. */ - Entry toCacheEntry(byte[] data) { - Entry e = new Entry(); - e.data = data; - e.etag = etag; - e.serverDate = serverDate; - e.lastModified = lastModified; - e.ttl = ttl; - e.softTtl = softTtl; - e.responseHeaders = HttpHeaderParser.toHeaderMap(allResponseHeaders); - e.allResponseHeaders = Collections.unmodifiableList(allResponseHeaders); - return e; - } - - /** Writes the contents of this CacheHeader to the specified OutputStream. */ - boolean writeHeader(OutputStream os) { - try { - writeInt(os, CACHE_MAGIC); - writeString(os, key); - writeString(os, etag == null ? "" : etag); - writeLong(os, serverDate); - writeLong(os, lastModified); - writeLong(os, ttl); - writeLong(os, softTtl); - writeHeaderList(allResponseHeaders, os); - os.flush(); - return true; - } catch (IOException e) { - VolleyLog.d("%s", e.toString()); - return false; - } - } - } - - @VisibleForTesting - static class CountingInputStream extends FilterInputStream { - private final long length; - private long bytesRead; - - CountingInputStream(InputStream in, long length) { - super(in); - this.length = length; - } - - @Override - public int read() throws IOException { - int result = super.read(); - if (result != -1) { - bytesRead++; - } - return result; - } - - @Override - public int read(byte[] buffer, int offset, int count) throws IOException { - int result = super.read(buffer, offset, count); - if (result != -1) { - bytesRead += result; - } - return result; - } - - @VisibleForTesting - long bytesRead() { - return bytesRead; - } - - long bytesRemaining() { - return length - bytesRead; - } - } - - /* - * Homebrewed simple serialization system used for reading and writing cache - * headers on disk. Once upon a time, this used the standard Java - * Object{Input,Output}Stream, but the default implementation relies heavily - * on reflection (even for standard types) and generates a ton of garbage. - * - * TODO: Replace by standard DataInput and DataOutput in next cache version. - */ - - /** - * Simple wrapper around {@link InputStream#read()} that throws EOFException instead of - * returning -1. - */ - private static int read(InputStream is) throws IOException { - int b = is.read(); - if (b == -1) { - throw new EOFException(); - } - return b; - } - - static void writeInt(OutputStream os, int n) throws IOException { - os.write((n >> 0) & 0xff); - os.write((n >> 8) & 0xff); - os.write((n >> 16) & 0xff); - os.write((n >> 24) & 0xff); - } - - static int readInt(InputStream is) throws IOException { - int n = 0; - n |= (read(is) << 0); - n |= (read(is) << 8); - n |= (read(is) << 16); - n |= (read(is) << 24); - return n; - } - - static void writeLong(OutputStream os, long n) throws IOException { - os.write((byte) (n >>> 0)); - os.write((byte) (n >>> 8)); - os.write((byte) (n >>> 16)); - os.write((byte) (n >>> 24)); - os.write((byte) (n >>> 32)); - os.write((byte) (n >>> 40)); - os.write((byte) (n >>> 48)); - os.write((byte) (n >>> 56)); - } - - static long readLong(InputStream is) throws IOException { - long n = 0; - n |= ((read(is) & 0xFFL) << 0); - n |= ((read(is) & 0xFFL) << 8); - n |= ((read(is) & 0xFFL) << 16); - n |= ((read(is) & 0xFFL) << 24); - n |= ((read(is) & 0xFFL) << 32); - n |= ((read(is) & 0xFFL) << 40); - n |= ((read(is) & 0xFFL) << 48); - n |= ((read(is) & 0xFFL) << 56); - return n; - } - - static void writeString(OutputStream os, String s) throws IOException { - byte[] b = s.getBytes("UTF-8"); - writeLong(os, b.length); - os.write(b, 0, b.length); - } - - static String readString(CountingInputStream cis) throws IOException { - long n = readLong(cis); - byte[] b = streamToBytes(cis, n); - return new String(b, "UTF-8"); - } - - static void writeHeaderList(List<Header> headers, OutputStream os) throws IOException { - if (headers != null) { - writeInt(os, headers.size()); - for (Header header : headers) { - writeString(os, header.getName()); - writeString(os, header.getValue()); - } - } else { - writeInt(os, 0); - } - } - - static List<Header> readHeaderList(CountingInputStream cis) throws IOException { - int size = readInt(cis); - if (size < 0) { - throw new IOException("readHeaderList size=" + size); - } - List<Header> result = - (size == 0) ? Collections.<Header>emptyList() : new ArrayList<Header>(); - for (int i = 0; i < size; i++) { - String name = readString(cis).intern(); - String value = readString(cis).intern(); - result.add(new Header(name, value)); - } - return result; - } -} |