diff options
| -rw-r--r-- | media/java/android/media/MiniThumbFile.java | 163 |
1 files changed, 160 insertions, 3 deletions
diff --git a/media/java/android/media/MiniThumbFile.java b/media/java/android/media/MiniThumbFile.java index 63b149c..9825857 100644 --- a/media/java/android/media/MiniThumbFile.java +++ b/media/java/android/media/MiniThumbFile.java @@ -45,8 +45,14 @@ import java.util.Hashtable; */ public class MiniThumbFile { private static final String TAG = "MiniThumbFile"; - private static final int MINI_THUMB_DATA_FILE_VERSION = 3; + private static final int MINI_THUMB_DATA_FILE_VERSION = 4; public static final int BYTES_PER_MINTHUMB = 10000; + + private static final int BYTES_PER_MINTHUMB_INDEX = 8; + private FileChannel mIndexChannel; + private RandomAccessFile mMiniThumbIndexFile; + private final boolean debug = false;; + private static final int HEADER_SIZE = 1 + 8 + 4; private Uri mUri; private RandomAccessFile mMiniThumbFile; @@ -98,6 +104,57 @@ public class MiniThumbFile { } } + private String randomAccessIndexFilePath(int version) { + String directoryName = + Environment.getExternalStorageDirectory().toString() + + "/DCIM/.thumbnails"; + return directoryName + "/.thumbindex" + version + "-" + mUri.hashCode(); + } + + private void removeOldIndexFile() { + String oldPath = randomAccessIndexFilePath(MINI_THUMB_DATA_FILE_VERSION - 1); + File oldFile = new File(oldPath); + if (oldFile.exists()) { + try { + oldFile.delete(); + } catch (SecurityException ex) { + // ignore + } + } + } + + private RandomAccessFile miniThumbIndexFile() { + if (mMiniThumbIndexFile == null) { + removeOldIndexFile(); + String path = randomAccessIndexFilePath(MINI_THUMB_DATA_FILE_VERSION); + File directory = new File(path).getParentFile(); + if (!directory.isDirectory()) { + if (!directory.mkdirs()) { + Log.e(TAG, "Unable to create .thumbnails directory " + + directory.toString()); + } + } + File f = new File(path); + + try { + mMiniThumbIndexFile = new RandomAccessFile(f, "rw"); + } catch (IOException ex) { + // Open as read-only so we can at least read the existing + // thumbnails. + try { + mMiniThumbIndexFile = new RandomAccessFile(f, "r"); + } catch (IOException ex2) { + // ignore exception + Log.e(TAG, "miniThumbIndexFile open r exception: " + f); + } + } + if (mMiniThumbIndexFile != null) { + mIndexChannel = mMiniThumbIndexFile.getChannel(); + } + } + return mMiniThumbIndexFile; + } + private RandomAccessFile miniThumbDataFile() { if (mMiniThumbFile == null) { removeOldFile(); @@ -128,6 +185,8 @@ public class MiniThumbFile { return mMiniThumbFile; } + + public MiniThumbFile(Uri uri) { mUri = uri; mBuffer = ByteBuffer.allocateDirect(BYTES_PER_MINTHUMB); @@ -144,6 +203,94 @@ public class MiniThumbFile { } } + /** + * Get the index of thumbnail, which is the real saving location. + * @param id the raw id in Mediaprovider database. + * @param create when you want to create a new thumbnail, set to true; when generally query + * thumbnail saved index, set to false. + */ + private long getIndex(long id, boolean create){ + RandomAccessFile r = miniThumbIndexFile(); + ByteBuffer buf = ByteBuffer.allocateDirect(BYTES_PER_MINTHUMB_INDEX); + + if (r != null) { + long pos = 0; + //first 8 bytes are for saving next create thumbnail block number! + //so if create set, then begin from 0, others begin from real index + // (id+1)*BYTES_PER_MINTHUMB_INDEX. + if (!create) { + pos = (id + 1) * BYTES_PER_MINTHUMB_INDEX; + } + + FileLock lock = null; + try { + buf.clear(); + buf.limit(BYTES_PER_MINTHUMB_INDEX); + + lock = mIndexChannel.lock(pos, BYTES_PER_MINTHUMB_INDEX, false); + //check that we can read the following 8 bytes + //which is the index position of thumbnail. + + int read = mIndexChannel.read(buf, pos); + + if (read == BYTES_PER_MINTHUMB_INDEX) { + buf.position(0); + if (create) { + //first, write next index. + long now = buf.getLong(); + buf.clear(); + buf.position(0); + buf.putLong(++now); + buf.flip(); + int write = mIndexChannel.write(buf, pos); + + //second, write this id's index + if(BYTES_PER_MINTHUMB_INDEX == write) { + if (lock != null) lock.release(); + pos = (id + 1) * BYTES_PER_MINTHUMB_INDEX; + lock = mIndexChannel.lock(pos, BYTES_PER_MINTHUMB_INDEX, false); + buf.flip(); + write = mIndexChannel.write(buf, pos); + if(debug) Log.d(TAG, "getIndex with create. index: " + now + + "corresponding id: " + id + ", index is: " + pos); + } + return now; + } else { + long p = buf.getLong(); + if(debug) Log.d(TAG, "getIndex with no create. index: " + p); + return p; + } + } else if(-1 == read) { + //If the index file is empty, initialize first index to 0. + if(0 == r.length()){ + buf.clear(); + buf.position(0); + buf.putLong(0); + buf.flip(); + int write = mIndexChannel.write(buf, 0); + if(debug) Log.d(TAG, "initialize first index"); + if(BYTES_PER_MINTHUMB_INDEX == write) return 0; + } + } + } catch (IOException ex) { + Log.e(TAG, "Got exception checking file index: ", ex); + } catch (RuntimeException ex) { + // Other NIO related exception like disk full, read only channel..etc + Log.e(TAG, "Got exception when reading index, id = " + id + + ", disk full or mount read-only? " + ex.getClass()); + } finally { + try { + if (lock != null) lock.release(); + } + catch (IOException ex) { + // ignore it. + Log.e(TAG, "release lock: ", ex); + } + } + } + return 0; + } + // Get the magic number for the specified id in the mini-thumb file. // Returns 0 if the magic is not available. public synchronized long getMagic(long id) { @@ -151,8 +298,14 @@ public class MiniThumbFile { // defined as having the right magic number at the offset // reserved for this "id". RandomAccessFile r = miniThumbDataFile(); + if (r != null) { - long pos = id * BYTES_PER_MINTHUMB; + + long pos = getIndex(id, false); + if(pos < 0) return 0; + + pos *= BYTES_PER_MINTHUMB; + FileLock lock = null; try { mBuffer.clear(); @@ -190,7 +343,11 @@ public class MiniThumbFile { RandomAccessFile r = miniThumbDataFile(); if (r == null) return; - long pos = id * BYTES_PER_MINTHUMB; + + long pos = getIndex(id, true); + if(pos < 0) return; + + pos *= BYTES_PER_MINTHUMB; FileLock lock = null; try { if (data != null) { |