Examples with FileLock java.nio.channels.FileLock used on opensource projects

Example 36 with FileLock

use of java.nio.channels.FileLock in project android_frameworks_base by DirtyUnicorns.

the class MiniThumbFile method getMiniThumbFromFile.

/**
     * Gallery app can use this method to retrieve mini-thumbnail. Full size
     * images share the same IDs with their corresponding thumbnails.
     *
     * @param id the ID of the image (same of full size image).
     * @param data the buffer to store mini-thumbnail.
     */
public synchronized byte[] getMiniThumbFromFile(long id, byte[] data) {
    RandomAccessFile r = miniThumbDataFile();
    if (r == null)
        return null;
    long pos = getIndex(id, false);
    if (pos < 0)
        return null;
    pos *= BYTES_PER_MINTHUMB;
    FileLock lock = null;
    try {
        mBuffer.clear();
        lock = mChannel.lock(pos, BYTES_PER_MINTHUMB, true);
        int size = mChannel.read(mBuffer, pos);
        if (size > 1 + 8 + 4) {
            // flag, magic, length
            mBuffer.position(0);
            byte flag = mBuffer.get();
            long magic = mBuffer.getLong();
            int length = mBuffer.getInt();
            if (size >= 1 + 8 + 4 + length && length != 0 && magic != 0 && flag == 1 && data.length >= length) {
                mBuffer.get(data, 0, length);
                return data;
            }
        }
    } catch (IOException ex) {
        Log.w(TAG, "got exception when reading thumbnail id=" + id + ", exception: " + ex);
    } catch (RuntimeException ex) {
        // Other NIO related exception like disk full, read only channel..etc
        Log.e(TAG, "Got exception when reading thumbnail, id = " + id + ", disk full or mount read-only? " + ex.getClass());
    } finally {
        try {
            if (lock != null)
                lock.release();
        } catch (IOException ex) {
        // ignore it.
        }
    }
    return null;
}

Example 37 with FileLock

use of java.nio.channels.FileLock in project android_frameworks_base by DirtyUnicorns.

the class MiniThumbFile method getMagic.

// 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) {
    // check the mini thumb file for the right data.  Right is
    // defined as having the right magic number at the offset
    // reserved for this "id".
    RandomAccessFile r = miniThumbDataFile();
    if (r != null) {
        long pos = getIndex(id, false);
        if (pos < 0)
            return 0;
        pos *= BYTES_PER_MINTHUMB;
        FileLock lock = null;
        try {
            mBuffer.clear();
            mBuffer.limit(1 + 8);
            lock = mChannel.lock(pos, 1 + 8, true);
            // (1 for the "status" and 8 for the long)
            if (mChannel.read(mBuffer, pos) == 9) {
                mBuffer.position(0);
                if (mBuffer.get() == 1) {
                    return mBuffer.getLong();
                }
            }
        } catch (IOException ex) {
            Log.v(TAG, "Got exception checking file magic: ", ex);
        } catch (RuntimeException ex) {
            // Other NIO related exception like disk full, read only channel..etc
            Log.e(TAG, "Got exception when reading magic, id = " + id + ", disk full or mount read-only? " + ex.getClass());
        } finally {
            try {
                if (lock != null)
                    lock.release();
            } catch (IOException ex) {
            // ignore it.
            }
        }
    }
    return 0;
}

Example 38 with FileLock

use of java.nio.channels.FileLock in project android_frameworks_base by DirtyUnicorns.

the class MiniThumbFile method saveMiniThumbToFile.

public synchronized void saveMiniThumbToFile(byte[] data, long id, long magic) throws IOException {
    RandomAccessFile r = miniThumbDataFile();
    if (r == null)
        return;
    long pos = getIndex(id, true);
    if (pos < 0)
        return;
    pos *= BYTES_PER_MINTHUMB;
    FileLock lock = null;
    try {
        if (data != null) {
            if (data.length > BYTES_PER_MINTHUMB - HEADER_SIZE) {
                // not enough space to store it.
                return;
            }
            mBuffer.clear();
            mBuffer.put((byte) 1);
            mBuffer.putLong(magic);
            mBuffer.putInt(data.length);
            mBuffer.put(data);
            mBuffer.flip();
            lock = mChannel.lock(pos, BYTES_PER_MINTHUMB, false);
            mChannel.write(mBuffer, pos);
        }
    } catch (IOException ex) {
        Log.e(TAG, "couldn't save mini thumbnail data for " + id + "; ", ex);
        throw ex;
    } catch (RuntimeException ex) {
        // Other NIO related exception like disk full, read only channel..etc
        Log.e(TAG, "couldn't save mini thumbnail data for " + id + "; disk full or mount read-only? " + ex.getClass());
    } finally {
        try {
            if (lock != null)
                lock.release();
        } catch (IOException ex) {
        // ignore it.
        }
    }
}

Example 39 with FileLock

use of java.nio.channels.FileLock in project azure-tools-for-java by Microsoft.

the class FileTokenCache method write.

private void write() throws IOException, InterruptedException {
    RandomAccessFile out = new RandomAccessFile(filePath.toString(), "rw");
    try {
        // in case of multiprocess file access
        FileLock lock = acquireLock(out);
        if (lock != null) {
            log.log(Level.FINEST, "Locking file cache for writing");
            try {
                byte[] data = serialize();
                log.log(Level.FINEST, "Writing file...");
                out.write(data);
            } finally {
                log.log(Level.FINEST, "Unocking file cache");
                lock.release();
            }
        } else {
            throw new IOException("Can't lock file token cache for writing");
        }
    } finally {
        out.close();
    }
}

Example 40 with FileLock

use of java.nio.channels.FileLock in project azure-tools-for-java by Microsoft.

the class FileTokenCache method read.

private void read() throws IOException, InterruptedException {
    RandomAccessFile in = new RandomAccessFile(filePath.toString(), "rw");
    try {
        // in case of multiprocess file access
        FileLock lock = acquireLock(in);
        if (lock != null) {
            log.log(Level.FINEST, "Locking file cache for reading...");
            try {
                int length = (int) new File(filePath.toString()).length();
                byte[] data = new byte[length];
                log.log(Level.FINEST, "Reading data...");
                in.read(data);
                deserialize(data);
            } finally {
                log.log(Level.FINEST, "Unocking file cache");
                lock.release();
            }
        } else {
            throw new IOException("Can't lock file token cache for reading");
        }
    } finally {
        in.close();
    }
}