commons-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Thomas Ledoux (JIRA)" <j...@apache.org>
Subject [jira] Created: (IO-90) Infinite loop in FileSystemUtils.freeSpaceWindows if share directory empty
Date Wed, 02 Aug 2006 17:15:13 GMT
Infinite loop in FileSystemUtils.freeSpaceWindows if share directory empty
--------------------------------------------------------------------------

                 Key: IO-90
                 URL: http://issues.apache.org/jira/browse/IO-90
             Project: Commons IO
          Issue Type: Bug
          Components: Utilities
    Affects Versions: 1.2
         Environment: Windows NT or higher
            Reporter: Thomas Ledoux


When using FileSystemUtils.freeSpaceWindows in an empty share directory, the line containing
the free space does not exist which causes an infinite loop (the outerloop doesn't decrease
the i index).

In fact to deal with all possible errors, I propose to test the exitCode of the dir command.

Here is a proposed new code for this function :

    /**
     * Find free space on the Windows platform using the 'dir' command.
     *
     * @param path  the path to get free space for, including the colon
     * @return the amount of free drive space on the drive
     * @throws IOException if an error occurs
     */
    long freeSpaceWindows(String path) throws IOException {
        path = FilenameUtils.normalize(path);
        if (path.length() > 2 && path.charAt(1) == ':') {
            path = path.substring(0, 2);  // seems to make it work
        }

        // build and run the 'dir' command
        String[] cmdAttrbs = new String[] {"cmd.exe", "/C", "dir /-c " + path};

        // read in the output of the command to an ArrayList
        BufferedReader in = null;
        String line = null;
        ArrayList lines = new ArrayList();
        int errorLevel = 0;
        
        try {
            Process proc = Runtime.getRuntime().exec(cmdAttrbs);
            in = new BufferedReader(
                new InputStreamReader(proc.getInputStream()));
            line = in.readLine();
            while (line != null) {
                line = line.toLowerCase().trim();
                lines.add(line);
                line = in.readLine();
            }
            
            proc.waitFor();
            errorLevel = proc.exitValue();
           
        } finally {
            IOUtils.closeQuietly(in);
        }

        if (lines.size() == 0) {
            // unknown problem, throw exception
            throw new IOException(
                    "Command line 'dir /-c' did not return any info " +
                    "for command '" + cmdAttrbs[2] + "'");
        }

        if (errorLevel != 0) {
            if (errorLevel == 2) {
                // Empty directory : unable to calculate the freeSpace
                return Integer.MAX_VALUE; // ???
            } else {
                // unknown problem, throw exception
                throw new IOException(
                        "Command line 'dir /-c' error [" + errorLevel +
                        "] for command '" + cmdAttrbs[2] + "'");
            }
        }
        
        // now iterate over the lines we just read and find the LAST
        // non-empty line (the free space bytes should be in the last element
        // of the ArrayList anyway, but this will ensure it works even if it's
        // not, still assuming it is on the last non-blank line)
        long bytes = -1;
        int i = lines.size() - 1;
        int bytesStart = 0;
        int bytesEnd = 0;
        outerLoop: while (i > 0) {
            line = (String) lines.get(i);
            if (line.length() > 0) {
                // found it, so now read from the end of the line to find the
                // last numeric character on the line, then continue until we
                // find the first non-numeric character, and everything between
                // that and the last numeric character inclusive is our free
                // space bytes count
                int j = line.length() - 1;
                innerLoop1: while (j >= 0) {
                    char c = line.charAt(j);
                    if (Character.isDigit(c)) {
                      // found the last numeric character, this is the end of
                      // the free space bytes count
                      bytesEnd = j + 1;
                      break innerLoop1;
                    }
                    j--;
                }
                innerLoop2: while (j >= 0) {
                    char c = line.charAt(j);
                    if (!Character.isDigit(c) && c != ',' && c != '.') {
                      // found the next non-numeric character, this is the
                      // beginning of the free space bytes count
                      bytesStart = j + 1;
                      break innerLoop2;
                    }
                    j--;
                }
                break outerLoop;
            } else {
                // If the last line is empty we are unable to parse the freeSpace
                throw new IOException(
                        "Command line 'dir /-c' did not return valid info " +
                        "for command '" + cmdAttrbs[2] + "'");
            }
        }

        // remove commas and dots in the bytes count
        StringBuffer buf = new StringBuffer(line.substring(bytesStart, bytesEnd));
        for (int k = 0; k < buf.length(); k++) {
            if (buf.charAt(k) == ',' || buf.charAt(k) == '.') {
                buf.deleteCharAt(k--);
            }
        }
        bytes = Long.parseLong(buf.toString());
        return bytes;
    }


-- 
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa
-
For more information on JIRA, see: http://www.atlassian.com/software/jira

        

---------------------------------------------------------------------
To unsubscribe, e-mail: commons-dev-unsubscribe@jakarta.apache.org
For additional commands, e-mail: commons-dev-help@jakarta.apache.org


Mime
View raw message