CODEWITHSUNDEEP
javacompareperforce
Ankit Kumar Singhal
Ankit Kumar Singhal

Reputation: 167

how to take diff of two versions of perforce depot file

how to check if the file content is same as the revision in server perforce JAVA API. Before updating any file into perforce depot, I want to check is there any difference in content of local file and the depot file. if there is no difference then ignore to submit that file.

Upvotes: 0

Views: 691

Answers (2)

Samwise
Samwise

Reputation: 71454

I think you want the getDiffFiles() method:

https://www.perforce.com/perforce/r15.1/manuals/p4java-javadoc/com/perforce/p4java/impl/mapbased/client/Client.html#getDiffFiles

Alternatively, for the specific thing you're doing (not submitting unchanged files), just use the "leaveUnchanged" submit option rather than doing the same work yourself.

Upvotes: 2

Aritra Roy
Aritra Roy

Reputation: 15615

Yes simple to do. Just generate a MD5 hash of the original file and before updating again generate a MD5 hash of the new file.

Now compare the hashes of both the files. If both are same, then the contents of both the files are same and if not then they are different and you are good to update.

Here is an utility to generate and check MD5 easily,

public class MD5Utils {
    private static final String TAG = "MD5";

    public static boolean checkMD5(String md5, File updateFile) {
        if (TextUtils.isEmpty(md5) || updateFile == null) {
            Log.e(TAG, "MD5 string empty or updateFile null");
            return false;
        }

        String calculatedDigest = calculateMD5(updateFile);
        if (calculatedDigest == null) {
            Log.e(TAG, "calculatedDigest null");
            return false;
        }

        Log.v(TAG, "Calculated digest: " + calculatedDigest);
        Log.v(TAG, "Provided digest: " + md5);

        return calculatedDigest.equalsIgnoreCase(md5);
    }

    public static String calculateMD5(File updateFile) {
        MessageDigest digest;
        try {
            digest = MessageDigest.getInstance("MD5");
        } catch (NoSuchAlgorithmException e) {
            Log.e(TAG, "Exception while getting digest", e);
            return null;
        }

        InputStream is;
        try {
            is = new FileInputStream(updateFile);
        } catch (FileNotFoundException e) {
            Log.e(TAG, "Exception while getting FileInputStream", e);
            return null;
        }

        byte[] buffer = new byte[8192];
        int read;
        try {
            while ((read = is.read(buffer)) > 0) {
                digest.update(buffer, 0, read);
            }
            byte[] md5sum = digest.digest();
            BigInteger bigInt = new BigInteger(1, md5sum);
            String output = bigInt.toString(16);
            // Fill to 32 chars
            output = String.format("%32s", output).replace(' ', '0');
            return output;
        } catch (IOException e) {
            throw new RuntimeException("Unable to process file for MD5", e);
        } finally {
            try {
                is.close();
            } catch (IOException e) {
                Log.e(TAG, "Exception on closing MD5 input stream", e);
            }
        }
    }
}

Upvotes: 2

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