private void checkAndAdvanceBlockInStream() throws IOException {
if (mCurrentBlockLeft == 0) {
if (mCurrentBlockInStream != null) {
mCurrentBlockInStream.close();
}
mCurrentBlockIndex = getCurrentBlockIndex();
mCurrentBlockInStream = BlockInStream.get(FILE, READ_TYPE, mCurrentBlockIndex);
mCurrentBlockLeft = BLOCK_CAPACITY;
}
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
if (b == null) {
throw new NullPointerException();
} else if (off < 0 || len < 0 || len > b.length - off) {
throw new IndexOutOfBoundsException();
} else if (len == 0) {
return 0;
}
int tOff = off;
int tLen = len;
while (tLen > 0 && mCurrentPosition < FILE_LENGTH) {
checkAndAdvanceBlockInStream();
int tRead = mCurrentBlockInStream.read(b, tOff, tLen);
mCurrentPosition += tRead;
mCurrentBlockLeft -= tRead;
tLen -= tRead;
tOff += tRead;
}
return len - tLen;
}
/**
* Return the {@code InStream} of this file based on the specified read type. If it has no block,
* return an {@code EmptyBlockInStream}; if it has only one block, return a {@code BlockInStream}
* of the block; otherwise return a {@code FileInStream}.
*
* @param readType the InStream's read type
* @return the InStream
* @throws IOException
*/
public InStream getInStream(ReadType readType) throws IOException {
if (readType == null) {
throw new IOException("ReadType can not be null.");
}
if (!isComplete()) {
throw new IOException("The file " + this + " is not complete.");
}
if (isDirectory()) {
throw new IOException("Cannot open a directory for reading.");
}
ClientFileInfo fileStatus = getUnCachedFileStatus();
List<Long> blocks = fileStatus.getBlockIds();
if (blocks.size() == 0) {
return new EmptyBlockInStream(this, readType, mTachyonConf);
}
if (blocks.size() == 1) {
return BlockInStream.get(this, readType, 0, mUFSConf, mTachyonConf);
}
return new FileInStream(this, readType, mUFSConf, mTachyonConf);
}
@Override
public void close() throws IOException {
if (!mClosed && mCurrentBlockInStream != null) {
mCurrentBlockInStream.close();
}
mClosed = true;
}
@Override
public void seek(long pos) throws IOException {
if (mCurrentPosition == pos) {
return;
}
if (pos < 0) {
throw new IOException("pos is negative: " + pos);
}
if ((int) (pos / BLOCK_CAPACITY) != mCurrentBlockIndex) {
mCurrentBlockIndex = (int) (pos / BLOCK_CAPACITY);
if (mCurrentBlockInStream != null) {
mCurrentBlockInStream.close();
}
mCurrentBlockInStream = BlockInStream.get(FILE, READ_TYPE, mCurrentBlockIndex);
}
mCurrentBlockInStream.seek(pos % BLOCK_CAPACITY);
mCurrentPosition = pos;
mCurrentBlockLeft = BLOCK_CAPACITY - (pos % BLOCK_CAPACITY);
}
@Override
public int read() throws IOException {
if (mCurrentPosition >= FILE_LENGTH) {
return -1;
}
checkAndAdvanceBlockInStream();
mCurrentPosition++;
mCurrentBlockLeft--;
return mCurrentBlockInStream.read();
}
@Override
public long skip(long n) throws IOException {
if (n <= 0) {
return 0;
}
long ret = n;
if (mCurrentPosition + n >= FILE.length()) {
ret = FILE.length() - mCurrentPosition;
mCurrentPosition += ret;
} else {
mCurrentPosition += n;
}
int tBlockIndex = (int) (mCurrentPosition / BLOCK_CAPACITY);
if (tBlockIndex != mCurrentBlockIndex) {
if (mCurrentBlockInStream != null) {
mCurrentBlockInStream.close();
}
mCurrentBlockIndex = tBlockIndex;
mCurrentBlockInStream = BlockInStream.get(FILE, READ_TYPE, mCurrentBlockIndex);
long shouldSkip = mCurrentPosition % BLOCK_CAPACITY;
long skip = mCurrentBlockInStream.skip(shouldSkip);
mCurrentBlockLeft = BLOCK_CAPACITY - skip;
if (skip != shouldSkip) {
throw new IOException(
"The underlayer BlockInStream only skip " + skip + " instead of " + shouldSkip);
}
} else {
long skip = mCurrentBlockInStream.skip(ret);
if (skip != ret) {
throw new IOException(
"The underlayer BlockInStream only skip " + skip + " instead of " + ret);
}
}
return ret;
}