/** Unchecked parameters version. */ private static void cp_r0( final boolean preserve, final java.io.File src, final java.io.File dst, final ArchiveDetector srcDetector, final ArchiveDetector dstDetector) throws IOException { if (src.isDirectory()) { final long srcLastModified = src.lastModified(); final boolean srcIsArchived = src instanceof File && ((File) src).getInnerArchive() != null; final boolean dstIsArchived = dst instanceof File && ((File) dst).getInnerArchive() != null; final boolean srcIsGhost = srcIsArchived && srcLastModified <= 0; if (!srcIsGhost || !dstIsArchived || !File.isLenient()) if (!dst.mkdir() && !dst.isDirectory()) throw new IOException("destination is not a directory"); final String[] members = src.list(); if (!srcIsArchived && dstIsArchived) { // Create sorted entries if writing a new archive. // This is a courtesy only, so natural order is sufficient. Arrays.sort(members); } for (int i = 0, l = members.length; i < l; i++) { final String member = members[i]; cp_r0( preserve, srcDetector.createFile(src, member), dstDetector.createFile(dst, member), srcDetector, dstDetector); } if (preserve && !srcIsGhost) if (!dst.setLastModified(srcLastModified)) throw new IOException("cannot set last modification time"); } else if (src.isFile() && (!dst.exists() || dst.isFile())) { cp0(preserve, src, dst); } else { throw new IOException("cannot copy non-existent or special files"); } }
/** * Returns <code>true</code> if the given file exists or can be created and at least one byte can * be successfully written to it - the file is restored to its previous state afterwards. This is * a much stronger test than {@link File#canWrite()}. * * <p>Please note that if the file is actually open for reading or other activities this method * may not be able to reset the last modification time of the file after testing, in which case * <code>false</code> is returned. This is known to apply to the Windows platform, but not on Unix * platforms. */ public static boolean isWritableOrCreatable(final java.io.File file) { try { if (!file.exists()) { final boolean created = file.createNewFile(); boolean ok = isWritableOrCreatable(file); if (created && !file.delete()) ok = false; // be conservative! return ok; } else if (file.canWrite()) { // Some operating and file system combinations make File.canWrite() // believe that the file is writable although it's not. // We are not that gullible, so let's test this... final long time = file.lastModified(); if (!file.setLastModified(time + 1)) { // This may happen on Windows and normally means that // somebody else has opened this file // (regardless of read or write mode). // Be conservative: We don't allow writing to this file! return false; } boolean ok; try { // Open the file for reading and writing, requiring any // update to its contents to be written to the filesystem // synchronously. // As Dr. Simon White from Catalysoft, Cambridge, UK reported, // "rws" does NOT work on Mac OS X with Apple's Java 1.5 // Release 1 (equivalent to Sun's Java 1.5.0_02), however // it DOES work with Apple's Java 1.5 Release 3. // He also confirmed that "rwd" works on Apple's // Java 1.5 Release 1, so we use this instead. // Thank you very much for spending the time to fix this // issue, Dr. White! final RandomAccessFile raf = new RandomAccessFile(file, "rwd"); try { final boolean empty; int octet = raf.read(); if (octet == -1) { octet = 0; // assume first byte is 0 empty = true; } else { empty = false; } // Let's test if we can (over)write the first byte. raf.seek(0); raf.write((octet ^ -1) & 0xFF); // write complement try { // Rewrite original content and check success. raf.seek(0); raf.write(octet); raf.seek(0); final int check = raf.read(); // This should always return true unless the storage // device is faulty. ok = octet == check; } finally { if (empty) raf.setLength(0); } } finally { raf.close(); } } finally { if (!file.setLastModified(time)) { // This may happen on Windows and normally means that // somebody else has opened this file meanwhile // (regardless of read or write mode). // Be conservative: We don't allow (further) writing to // this file! ok = false; } } return ok; } else { // if (file.exists() && !file.canWrite()) { return false; } } catch (IOException ex) { return false; // don't allow writing if anything goes wrong! } }