/** 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); CountingInputStream cis = null; try { cis = new CountingInputStream(new BufferedInputStream(new FileInputStream(file))); CacheHeader.readHeader(cis); // eat header byte[] data = streamToBytes(cis, (int) (file.length() - cis.bytesRead)); return entry.toCacheEntry(data); } catch (IOException e) { VolleyLog.d("%s: %s", file.getAbsolutePath(), e.toString()); remove(key); return null; } finally { if (cis != null) { try { cis.close(); } catch (IOException ioe) { return null; } } } }
/** 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)); } }
/** 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."); }
/** 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(new FileOutputStream(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()); } }
/** Writes the contents of this CacheHeader to the specified OutputStream. */ public 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); writeStringStringMap(responseHeaders, os); os.flush(); return true; } catch (IOException e) { VolleyLog.d("%s", e.toString()); return false; } }
/** * 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); } }