/**
* Read block from file.
*
* @param file - File to read.
* @param off - Marker position in file to start read from if {@code -1} read last blockSz bytes.
* @param blockSz - Maximum number of chars to read.
* @param lastModified - File last modification time.
* @return Read file block.
* @throws IOException In case of error.
*/
public static VisorFileBlock readBlock(File file, long off, int blockSz, long lastModified)
throws IOException {
RandomAccessFile raf = null;
try {
long fSz = file.length();
long fLastModified = file.lastModified();
long pos = off >= 0 ? off : Math.max(fSz - blockSz, 0);
// Try read more that file length.
if (fLastModified == lastModified && fSz != 0 && pos >= fSz)
throw new IOException(
"Trying to read file block with wrong offset: " + pos + " while file size: " + fSz);
if (fSz == 0)
return new VisorFileBlock(file.getPath(), pos, fLastModified, 0, false, EMPTY_FILE_BUF);
else {
int toRead = Math.min(blockSz, (int) (fSz - pos));
byte[] buf = new byte[toRead];
raf = new RandomAccessFile(file, "r");
raf.seek(pos);
int cntRead = raf.read(buf, 0, toRead);
if (cntRead != toRead)
throw new IOException(
"Count of requested and actually read bytes does not match [cntRead="
+ cntRead
+ ", toRead="
+ toRead
+ ']');
boolean zipped = buf.length > 512;
return new VisorFileBlock(
file.getPath(), pos, fSz, fLastModified, zipped, zipped ? zipBytes(buf) : buf);
}
} finally {
U.close(raf, null);
}
}
/**
* Check is text file.
*
* @param f file reference.
* @param emptyOk default value if empty file.
* @return Is text file.
*/
public static boolean textFile(File f, boolean emptyOk) {
if (f.length() == 0) return emptyOk;
String detected = VisorMimeTypes.getContentType(f);
for (String mime : TEXT_MIME_TYPE) if (mime.equals(detected)) return true;
return false;
}
/**
* Finds all files in folder and in it's sub-tree of specified depth.
*
* @param file Starting folder
* @param maxDepth Depth of the tree. If 1 - just look in the folder, no sub-folders.
* @param filter file filter.
* @return List of found files.
*/
public static List<VisorLogFile> fileTree(File file, int maxDepth, @Nullable FileFilter filter) {
if (file.isDirectory()) {
File[] files = (filter == null) ? file.listFiles() : file.listFiles(filter);
if (files == null) return Collections.emptyList();
List<VisorLogFile> res = new ArrayList<>(files.length);
for (File f : files) {
if (f.isFile() && f.length() > 0) res.add(new VisorLogFile(f));
else if (maxDepth > 1) res.addAll(fileTree(f, maxDepth - 1, filter));
}
return res;
}
return F.asList(new VisorLogFile(file));
}