/**
* Seek to the given offset from the start of the file. The next read() will be from that
* location. Can't seek past the end of the file.
*/
@Override
public void seek(long pos) throws IOException {
if (pos == mCurrentPosition) {
return;
}
if (pos < mCurrentPosition) {
throw new IOException(
"Not supported to seek to " + pos + " . Current Position is " + mCurrentPosition);
}
if (mTachyonFileInputStream != null) {
long needSkip = pos - mCurrentPosition;
while (needSkip > 0) {
needSkip -= mTachyonFileInputStream.skip(needSkip);
}
mCurrentPosition = pos;
} else if (mHdfsInputStream != null) {
mHdfsInputStream.seek(pos);
mCurrentPosition = pos;
}
}
/**
* This function displays 5KB of a file from a specific offset if it is in ASCII format.
*
* @param path The path of the file to display
* @param request The HttpServletRequest object
* @param offset Where the file starts to display.
* @throws FileDoesNotExistException
* @throws IOException
* @throws InvalidPathException
*/
private void displayFile(String path, HttpServletRequest request, long offset)
throws FileDoesNotExistException, InvalidPathException, IOException {
String masterAddress =
Constants.HEADER
+ mMasterInfo.getMasterAddress().getHostName()
+ ":"
+ mMasterInfo.getMasterAddress().getPort();
TachyonFS tachyonClient = TachyonFS.get(masterAddress);
TachyonFile tFile = tachyonClient.getFile(path);
String fileData = null;
if (tFile == null) {
throw new FileDoesNotExistException(path);
}
if (tFile.isComplete()) {
InStream is = tFile.getInStream(ReadType.NO_CACHE);
int len = (int) Math.min(5 * Constants.KB, tFile.length() - offset);
byte[] data = new byte[len];
is.skip(offset);
is.read(data, 0, len);
fileData = CommonUtils.convertByteArrayToStringWithoutEscape(data);
if (fileData == null) {
fileData = "The requested file is not completely encoded in ascii";
}
is.close();
} else {
fileData = "The requested file is not complete yet.";
}
try {
tachyonClient.close();
} catch (IOException e) {
LOG.error(e.getMessage());
}
List<BlockInfo> rawBlockList = mMasterInfo.getBlockList(path);
List<UiBlockInfo> uiBlockInfo = new ArrayList<UiBlockInfo>();
for (BlockInfo blockInfo : rawBlockList) {
uiBlockInfo.add(new UiBlockInfo(blockInfo));
}
request.setAttribute("fileBlocks", uiBlockInfo);
request.setAttribute("fileData", fileData);
}