这是一些cache缓存的基本接口，没有身体特别的地方
package com.android.volley;
import java.util.Collections;
import java.util.List;
import java.util.Map;
/** An interface for a cache keyed by a String with a byte array as data. */
public interface Cache {
/**
* Retrieves an entry from the cache.
*
* @param key Cache key
* @return An {@link Entry} or null in the event of a cache miss
*/
Entry get(String key);
/**
* Adds or replaces an entry to the cache.
*
* @param key Cache key
* @param entry Data to store and metadata for cache coherency, TTL, etc.
*/
void put(String key, Entry entry);
/**
* Performs any potentially long-running actions needed to initialize the cache; will be called
* from a worker thread.
*/
void initialize();
/**
* Invalidates an entry in the cache.
*
* @param key Cache key
* @param fullExpire True to fully expire the entry, false to soft expire
*/
void invalidate(String key, boolean fullExpire);
/**
* Removes an entry from the cache.
*
* @param key Cache key
*/
void remove(String key);
/** Empties the cache. */
void clear();
/** Data and metadata for an entry returned by the cache. */
class Entry {
/** The data returned from cache. */
public byte[] data;
/** ETag for cache coherency. */
public String etag;
/** Date of this response as reported by the server. */
public long serverDate;
/** The last modified date for the requested object. */
public long lastModified;
/** TTL for this record. */
public long ttl;
/** Soft TTL for this record. */
public long softTtl;
/**
* Response headers as received from server; must be non-null. Should not be mutated
* directly.
*
* <p>Note that if the server returns two headers with the same (case-insensitive) name,
* this map will only contain the one of them. {@link #allResponseHeaders} may contain all
* headers if the {@link Cache} implementation supports it.
*/
public Map<String, String> responseHeaders = Collections.emptyMap();
/**
* All response headers. May be null depending on the {@link Cache} implementation. Should
* not be mutated directly.
*/
public List<Header> allResponseHeaders;
/** True if the entry is expired. */
public boolean isExpired() {
return this.ttl < System.currentTimeMillis();
}
/** True if a refresh is needed from the original data source. */
public boolean refreshNeeded() {
return this.softTtl < System.currentTimeMillis();
}
}
}缓存分发类 CacheDispatcher
package com.android.volley;
import android.os.Process;
import android.support.annotation.VisibleForTesting;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.BlockingQueue;
/**
* Provides a thread for performing cache triage on a queue of requests.
*
* <p>Requests added to the specified cache queue are resolved from cache. Any deliverable response
* is posted back to the caller via a {@link ResponseDelivery}. Cache misses and responses that
* require refresh are enqueued on the specified network queue for processing by a {@link
* NetworkDispatcher}.
*
*/
public class CacheDispatcher extends Thread {
private static final boolean DEBUG = VolleyLog.DEBUG;
/** The queue of requests coming in for triage. */
private final BlockingQueue<Request<?>> mCacheQueue;
/** The queue of requests going out to the network. */
private final BlockingQueue<Request<?>> mNetworkQueue;
/** The cache to read from. */
private final Cache mCache;
/** For posting responses. */
private final ResponseDelivery mDelivery;
/** Used for telling us to die. */
private volatile boolean mQuit = false;
/** Manage list of waiting requests and de-duplicate requests with same cache key. */
private final WaitingRequestManager mWaitingRequestManager;
/**
* Creates a new cache triage dispatcher thread. You must call {@link #start()} in order to
* begin processing.
*
* @param cacheQueue Queue of incoming requests for triage
* @param networkQueue Queue to post requests that require network to
* @param cache Cache interface to use for resolution
* @param delivery Delivery interface to use for posting responses
*/
public CacheDispatcher(
BlockingQueue<Request<?>> cacheQueue,
BlockingQueue<Request<?>> networkQueue,
Cache cache,
ResponseDelivery delivery) {
mCacheQueue = cacheQueue;
mNetworkQueue = networkQueue;
mCache = cache;
mDelivery = delivery;
mWaitingRequestManager = new WaitingRequestManager(this);
}
/**
* Forces this dispatcher to quit immediately. If any requests are still in the queue, they are
* not guaranteed to be processed.
*/
public void quit() {
mQuit = true;
interrupt();
}
@Override
public void run() {
if (DEBUG) VolleyLog.v("start new dispatcher");
Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);
// Make a blocking call to initialize the cache.
mCache.initialize();
while (true) {
try {
processRequest();
} catch (InterruptedException e) {
// We may have been interrupted because it was time to quit.
if (mQuit) {
Thread.currentThread().interrupt();
return;
}
VolleyLog.e(
"Ignoring spurious interrupt of CacheDispatcher thread; "
+ "use quit() to terminate it");
}
}
}
// Extracted to its own method to ensure locals have a constrained liveness scope by the GC.
// This is needed to avoid keeping previous request references alive for an indeterminate amount
// of time. Update consumer-proguard-rules.pro when modifying this. See also
// https://github.com/google/volley/issues/114
private void processRequest() throws InterruptedException {
// Get a request from the cache triage queue, blocking until
// at least one is available.
final Request<?> request = mCacheQueue.take();
processRequest(request);
}
@VisibleForTesting
void processRequest(final Request<?> request) throws InterruptedException {
request.addMarker("cache-queue-take");
// If the request has been canceled, don't bother dispatching it.
if (request.isCanceled()) {
request.finish("cache-discard-canceled");
return;
}
// Attempt to retrieve this item from cache.
Cache.Entry entry = mCache.get(request.getCacheKey());
if (entry == null) {
request.addMarker("cache-miss");
// Cache miss; send off to the network dispatcher.
if (!mWaitingRequestManager.maybeAddToWaitingRequests(request)) {
mNetworkQueue.put(request);
}
return;
}
// If it is completely expired, just send it to the network.
if (entry.isExpired()) {
request.addMarker("cache-hit-expired");
request.setCacheEntry(entry);
if (!mWaitingRequestManager.maybeAddToWaitingRequests(request)) {
mNetworkQueue.put(request);
}
return;
}
// We have a cache hit; parse its data for delivery back to the request.
request.addMarker("cache-hit");
Response<?> response =
request.parseNetworkResponse(
new NetworkResponse(entry.data, entry.responseHeaders));
request.addMarker("cache-hit-parsed");
if (!entry.refreshNeeded()) {
// Completely unexpired cache hit. Just deliver the response.
mDelivery.postResponse(request, response);
} else {
// Soft-expired cache hit. We can deliver the cached response,
// but we need to also send the request to the network for
// refreshing.
request.addMarker("cache-hit-refresh-needed");
request.setCacheEntry(entry);
// Mark the response as intermediate.
response.intermediate = true;
if (!mWaitingRequestManager.maybeAddToWaitingRequests(request)) {
// Post the intermediate response back to the user and have
// the delivery then forward the request along to the network.
mDelivery.postResponse(
request,
response,
new Runnable() {
@Override
public void run() {
try {
mNetworkQueue.put(request);
} catch (InterruptedException e) {
// Restore the interrupted status
Thread.currentThread().interrupt();
}
}
});
} else {
// request has been added to list of waiting requests
// to receive the network response from the first request once it returns.
mDelivery.postResponse(request, response);
}
}
}
private static class WaitingRequestManager implements Request.NetworkRequestCompleteListener {
/**
* Staging area for requests that already have a duplicate request in flight.
*
* <ul>
* <li>containsKey(cacheKey) indicates that there is a request in flight for the given
* cache key.
* <li>get(cacheKey) returns waiting requests for the given cache key. The in flight
* request is <em>not</em> contained in that list. Is null if no requests are staged.
* </ul>
*/
private final Map<String, List<Request<?>>> mWaitingRequests = new HashMap<>();
private final CacheDispatcher mCacheDispatcher;
WaitingRequestManager(CacheDispatcher cacheDispatcher) {
mCacheDispatcher = cacheDispatcher;
}
/** Request received a valid response that can be used by other waiting requests. */
@Override
public void onResponseReceived(Request<?> request, Response<?> response) {
if (response.cacheEntry == null || response.cacheEntry.isExpired()) {
onNoUsableResponseReceived(request);
return;
}
String cacheKey = request.getCacheKey();
List<Request<?>> waitingRequests;
synchronized (this) {
waitingRequests = mWaitingRequests.remove(cacheKey);
}
if (waitingRequests != null) {
if (VolleyLog.DEBUG) {
VolleyLog.v(
"Releasing %d waiting requests for cacheKey=%s.",
waitingRequests.size(), cacheKey);
}
// Process all queued up requests.
for (Request<?> waiting : waitingRequests) {
mCacheDispatcher.mDelivery.postResponse(waiting, response);
}
}
}
/** No valid response received from network, release waiting requests. */
@Override
public synchronized void onNoUsableResponseReceived(Request<?> request) {
String cacheKey = request.getCacheKey();
List<Request<?>> waitingRequests = mWaitingRequests.remove(cacheKey);
if (waitingRequests != null && !waitingRequests.isEmpty()) {
if (VolleyLog.DEBUG) {
VolleyLog.v(
"%d waiting requests for cacheKey=%s; resend to network",
waitingRequests.size(), cacheKey);
}
Request<?> nextInLine = waitingRequests.remove(0);
mWaitingRequests.put(cacheKey, waitingRequests);
nextInLine.setNetworkRequestCompleteListener(this);
try {
mCacheDispatcher.mNetworkQueue.put(nextInLine);
} catch (InterruptedException iex) {
VolleyLog.e("Couldn't add request to queue. %s", iex.toString());
// Restore the interrupted status of the calling thread (i.e. NetworkDispatcher)
Thread.currentThread().interrupt();
// Quit the current CacheDispatcher thread.
mCacheDispatcher.quit();
}
}
}
/**
* For cacheable requests, if a request for the same cache key is already in flight, add it
* to a queue to wait for that in-flight request to finish.
*
* @return whether the request was queued. If false, we should continue issuing the request
* over the network. If true, we should put the request on hold to be processed when the
* in-flight request finishes.
*/
private synchronized boolean maybeAddToWaitingRequests(Request<?> request) {
String cacheKey = request.getCacheKey();
// Insert request into stage if there's already a request with the same cache key
// in flight.
if (mWaitingRequests.containsKey(cacheKey)) {
// There is already a request in flight. Queue up.
List<Request<?>> stagedRequests = mWaitingRequests.get(cacheKey);
if (stagedRequests == null) {
stagedRequests = new ArrayList<>();
}
request.addMarker("waiting-for-response");
stagedRequests.add(request);
mWaitingRequests.put(cacheKey, stagedRequests);
if (VolleyLog.DEBUG) {
VolleyLog.d("Request for cacheKey=%s is in flight, putting on hold.", cacheKey);
}
return true;
} else {
// Insert 'null' queue for this cacheKey, indicating there is now a request in
// flight.
mWaitingRequests.put(cacheKey, null);
request.setNetworkRequestCompleteListener(this);
if (VolleyLog.DEBUG) {
VolleyLog.d("new request, sending to network %s", cacheKey);
}
return false;
}
}
}
}
maybeAddToWaitingRequests() 这个方法值得去学习，通过map添加list,添加请求队列。
没有缓存的类
package com.android.volley.toolbox;
import com.android.volley.Cache;
/** A cache that doesn't. */
public class NoCache implements Cache {
@Override
public void clear() {}
@Override
public Entry get(String key) {
return null;
}
@Override
public void put(String key, Entry entry) {}
@Override
public void invalidate(String key, boolean fullExpire) {}
@Override
public void remove(String key) {}
@Override
public void initialize() {}
}
文件类添加删除缓存操作
package com.android.volley.toolbox;
import android.os.SystemClock;
import android.support.annotation.VisibleForTesting;
import android.text.TextUtils;
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 root directory to use for the cache. */
private final File mRootDirectory;
/** 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 */
private 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.
*/
public DiskBasedCache(File rootDirectory, int maxCacheSizeInBytes) {
mRootDirectory = rootDirectory;
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);
}
/** Clears the cache. Deletes all cached files from disk. */
@Override
public synchronized void clear() {
File[] files = mRootDirectory.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() {
if (!mRootDirectory.exists()) {
if (!mRootDirectory.mkdirs()) {
VolleyLog.e("Unable to create cache dir %s", mRootDirectory.getAbsolutePath());
}
return;
}
File[] files = mRootDirectory.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);
// NOTE: When this entry was put, its size was recorded as data.length, but
// when the entry is initialized below, its size is recorded as file.length()
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) {
pruneIfNeeded(entry.data.length);
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();
putEntry(key, e);
return;
} catch (IOException e) {
}
boolean deleted = file.delete();
if (!deleted) {
VolleyLog.d("Could not clean up file %s", file.getAbsolutePath());
}
}
/** 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(mRootDirectory, getFilenameForKey(key));
}
/**
* Prunes the cache to fit the amount of bytes specified.
*
* @param neededSpace The amount of bytes we are trying to fit into the cache.
*/
private void pruneIfNeeded(int neededSpace) {
if ((mTotalSize + neededSpace) < 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 + neededSpace) < 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. (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));
size = entry.data.length;
}
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;
}
}