checksum.java

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                ct++;
            }
            if (ct > 1) {
                throw new BuildException(
                    "Multiple files cannot be used when Property is specified");
            }
        }
        if (verifyProperty != null) {
            isCondition = true;
        }
        if (verifyProperty != null && forceOverwrite) {
            throw new BuildException("VerifyProperty and ForceOverwrite cannot co-exist.");
        }
        if (isCondition && forceOverwrite) {
            throw new BuildException(
                "ForceOverwrite cannot be used when conditions are being used.");
        }
        messageDigest = null;
        if (provider != null) {
            try {
                messageDigest = MessageDigest.getInstance(algorithm, provider);
            } catch (NoSuchAlgorithmException noalgo) {
                throw new BuildException(noalgo, getLocation());
            } catch (NoSuchProviderException noprovider) {
                throw new BuildException(noprovider, getLocation());
            }
        } else {
            try {
                messageDigest = MessageDigest.getInstance(algorithm);
            } catch (NoSuchAlgorithmException noalgo) {
                throw new BuildException(noalgo, getLocation());
            }
        }
        if (messageDigest == null) {
            throw new BuildException("Unable to create Message Digest", getLocation());
        }
        if (fileext == null) {
            fileext = "." + algorithm;
        } else if (fileext.trim().length() == 0) {
            throw new BuildException("File extension when specified must not be an empty string");
        }
        try {
            if (resources != null) {
                for (Iterator i = resources.iterator(); i.hasNext();) {
                    FileResource fr = (FileResource) i.next();
                    File src = fr.getFile();
                    if (totalproperty != null || todir != null) {
                        // Use '/' to calculate digest based on file name.
                        // This is required in order to get the same result
                        // on different platforms.
                        relativeFilePaths.put(src, fr.getName().replace(File.separatorChar, '/'));
                    }
                    addToIncludeFileMap(src);
                }
            }
            if (file != null) {
                if (totalproperty != null || todir != null) {
                    relativeFilePaths.put(
                        file, file.getName().replace(File.separatorChar, '/'));
                }
                addToIncludeFileMap(file);
            }
            return generateChecksums();
        } finally {
            fileext = savedFileExt;
            includeFileMap.clear();
        }
    }

    /**
     * Add key-value pair to the hashtable upon which
     * to later operate upon.
     */
    private void addToIncludeFileMap(File file) throws BuildException {
        if (file.exists()) {
            if (property == null) {
                File checksumFile = getChecksumFile(file);
                if (forceOverwrite || isCondition
                    || (file.lastModified() > checksumFile.lastModified())) {
                    includeFileMap.put(file, checksumFile);
                } else {
                    log(file + " omitted as " + checksumFile + " is up to date.",
                        Project.MSG_VERBOSE);
                    if (totalproperty != null) {
                        // Read the checksum from disk.
                        String checksum = readChecksum(checksumFile);
                        byte[] digest = decodeHex(checksum.toCharArray());
                        allDigests.put(file, digest);
                    }
                }
            } else {
                includeFileMap.put(file, property);
            }
        } else {
            String message = "Could not find file "
                + file.getAbsolutePath()
                + " to generate checksum for.";
            log(message);
            throw new BuildException(message, getLocation());
        }
    }

    private File getChecksumFile(File file) {
        File directory;
        if (todir != null) {
            // A separate directory was explicitly declared
            String path = (String) relativeFilePaths.get(file);
            if (path == null) {
                //bug 37386. this should not occur, but it has, once.
                throw new BuildException(
                    "Internal error: "
                    + "relativeFilePaths could not match file"
                    + file + "\n"
                    + "please file a bug report on this");
            }
            directory = new File(todir, path).getParentFile();
            // Create the directory, as it might not exist.
            directory.mkdirs();
        } else {
            // Just use the same directory as the file itself.
            // This directory will exist
            directory = file.getParentFile();
        }
        File checksumFile = new File(directory, file.getName() + fileext);
        return checksumFile;
    }

    /**
     * Generate checksum(s) using the message digest created earlier.
     */
    private boolean generateChecksums() throws BuildException {
        boolean checksumMatches = true;
        FileInputStream fis = null;
        FileOutputStream fos = null;
        byte[] buf = new byte[readBufferSize];
        try {
            for (Enumeration e = includeFileMap.keys(); e.hasMoreElements();) {
                messageDigest.reset();
                File src = (File) e.nextElement();
                if (!isCondition) {
                    log("Calculating " + algorithm + " checksum for " + src, Project.MSG_VERBOSE);
                }
                fis = new FileInputStream(src);
                DigestInputStream dis = new DigestInputStream(fis,
                                                              messageDigest);
                while (dis.read(buf, 0, readBufferSize) != -1) {
                    // Empty statement
                }
                dis.close();
                fis.close();
                fis = null;
                byte[] fileDigest = messageDigest.digest ();
                if (totalproperty != null) {
                    allDigests.put(src, fileDigest);
                }
                String checksum = createDigestString(fileDigest);
                //can either be a property name string or a file
                Object destination = includeFileMap.get(src);
                if (destination instanceof java.lang.String) {
                    String prop = (String) destination;
                    if (isCondition) {
                        checksumMatches
                            = checksumMatches && checksum.equals(property);
                    } else {
                        getProject().setNewProperty(prop, checksum);
                    }
                } else if (destination instanceof java.io.File) {
                    if (isCondition) {
                        File existingFile = (File) destination;
                        if (existingFile.exists()) {
                            try {
                                String suppliedChecksum =
                                    readChecksum(existingFile);
                                checksumMatches = checksumMatches
                                    && checksum.equals(suppliedChecksum);
                            } catch (BuildException be) {
                                // file is on wrong format, swallow
                                checksumMatches = false;
                            }
                        } else {
                            checksumMatches = false;
                        }
                    } else {
                        File dest = (File) destination;
                        fos = new FileOutputStream(dest);
                        fos.write(format.format(new Object[] {
                                                    checksum,
                                                    src.getName(),
                                                }).getBytes());
                        fos.write(StringUtils.LINE_SEP.getBytes());
                        fos.close();
                        fos = null;
                    }
                }
            }
            if (totalproperty != null) {
                // Calculate the total checksum
                // Convert the keys (source files) into a sorted array.
                Set keys = allDigests.keySet();
                Object[] keyArray = keys.toArray();
                // File is Comparable, so sorting is trivial
                Arrays.sort(keyArray);
                // Loop over the checksums and generate a total hash.
                messageDigest.reset();
                for (int i = 0; i < keyArray.length; i++) {
                    File src = (File) keyArray[i];

                    // Add the digest for the file content
                    byte[] digest = (byte[]) allDigests.get(src);
                    messageDigest.update(digest);

                    // Add the file path
                    String fileName = (String) relativeFilePaths.get(src);
                    messageDigest.update(fileName.getBytes());
                }
                String totalChecksum = createDigestString(messageDigest.digest());
                getProject().setNewProperty(totalproperty, totalChecksum);
            }
        } catch (Exception e) {
            throw new BuildException(e, getLocation());
        } finally {
            FileUtils.close(fis);
            FileUtils.close(fos);
        }
        return checksumMatches;
    }

    private String createDigestString(byte[] fileDigest) {
        StringBuffer checksumSb = new StringBuffer();
        for (int i = 0; i < fileDigest.length; i++) {
            String hexStr = Integer.toHexString(0x00ff & fileDigest[i]);
            if (hexStr.length() < 2) {
                checksumSb.append("0");
            }
            checksumSb.append(hexStr);
        }
        return checksumSb.toString();
    }

    /**
     * Converts an array of characters representing hexadecimal values into an
     * array of bytes of those same values. The returned array will be half the
     * length of the passed array, as it takes two characters to represent any
     * given byte. An exception is thrown if the passed char array has an odd
     * number of elements.
     *
     * NOTE: This code is copied from jakarta-commons codec.
     * @param data an array of characters representing hexadecimal values
     * @return the converted array of bytes
     * @throws BuildException on error
     */
    public static byte[] decodeHex(char[] data) throws BuildException {
        int l = data.length;

        if ((l & 0x01) != 0) {
            throw new BuildException("odd number of characters.");
        }

        byte[] out = new byte[l >> 1];

        // two characters form the hex value.
        for (int i = 0, j = 0; j < l; i++) {
            int f = Character.digit(data[j++], 16) << 4;
            f = f | Character.digit(data[j++], 16);
            out[i] = (byte) (f & 0xFF);
        }

        return out;
    }

    /**
     * reads the checksum from a file using the specified format.
     *
     * @since 1.7
     */
    private String readChecksum(File f) {
        BufferedReader diskChecksumReader = null;
        try {
            diskChecksumReader = new BufferedReader(new FileReader(f));
            Object[] result = format.parse(diskChecksumReader.readLine());
            if (result == null || result.length == 0 || result[0] == null) {
                throw new BuildException("failed to find a checksum");
            }
            return (String) result[0];
        } catch (IOException e) {
            throw new BuildException("Couldn't read checksum file " + f, e);
        } catch (ParseException e) {
            throw new BuildException("Couldn't read checksum file " + f, e);
        } finally {
            FileUtils.close(diskChecksumReader);
        }
    }

    /**
     * Helper class for the format attribute.
     *
     * @since 1.7
     */
    public static class FormatElement extends EnumeratedAttribute {
        private static HashMap formatMap = new HashMap();
        private static final String CHECKSUM = "CHECKSUM";
        private static final String MD5SUM = "MD5SUM";
        private static final String SVF = "SVF";

        static {
            formatMap.put(CHECKSUM, new MessageFormat("{0}"));
            formatMap.put(MD5SUM, new MessageFormat("{0} *{1}"));
            formatMap.put(SVF, new MessageFormat("MD5 ({1}) = {0}"));
        }

        /** Constructor for FormatElement */
        public FormatElement() {
            super();
        }

        /**
         * Get the default value - CHECKSUM.
         * @return the defaul value.
         */
        public static FormatElement getDefault() {
            FormatElement e = new FormatElement();
            e.setValue(CHECKSUM);
            return e;
        }

        /**
         * Convert this enumerated type to a <code>MessageFormat</code>.
         * @return a <code>MessageFormat</code> object.
         */
        public MessageFormat getFormat() {
            return (MessageFormat) formatMap.get(getValue());
        }

        /**
         * Get the valid values.
         * @return an array of values.
         */
        public String[] getValues() {
            return new String[] {CHECKSUM, MD5SUM, SVF};
        }
    }
}