Home » Eclipse Projects » EGit / JGit » Eclipse JGit(Different SHA1Id generated for Windows and Linux file due to EOL difference )
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| Re: Eclipse JGit [message #1799408 is a reply to message #1799406] |
Thu, 06 December 2018 10:40   |
 Christian Halstrick
Messages: 264
Registered: July 2009 |
Senior Member |
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To compute a sha1 of a local file in a way you can compare it to sha1 which you find in git commit/blobs you would have to follow:
https://stackoverflow.com/a/24283352/3967955
The code in JGit which does this can be looked up here: https://git.eclipse.org/r/plugins/gitiles/jgit/jgit/+/v5.1.3.201810200350-r/org.eclipse.jgit/src/org/eclipse/jgit/treewalk/WorkingTreeIterator.java#1176
If you want to compute a SHA1 which has autoCRLF semantics then you should feed to the method above not a FileInputStream but JGits AutoCRLFInputStream
like
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import org.eclipse.jgit.api.errors.GitAPIException;
import org.eclipse.jgit.api.errors.JGitInternalException;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.util.sha1.SHA1;
public class CalcSHA1 {
public static void main(String args[]) throws IOException, GitAPIException, JGitInternalException {
try (InputStream in = new FileInputStream(args[0])) {
System.out.println(
"Git hash for file " + args[0] + " is " + ObjectId.fromRaw(computeHash(in, 1172)).getName());
}
}
private static final byte[] digits = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
protected static final byte[] zeroid = new byte[Constants.OBJECT_ID_LENGTH];
private static final byte[] hblob = Constants.encodedTypeString(Constants.OBJ_BLOB);
private static byte[] computeHash(InputStream in, long length) throws IOException {
SHA1 contentDigest = SHA1.newInstance();
final byte[] contentReadBuffer = new byte[4096];
contentDigest.update(hblob);
contentDigest.update((byte) ' ');
long sz = length;
if (sz == 0) {
contentDigest.update((byte) '0');
} else {
final int bufn = contentReadBuffer.length;
int p = bufn;
do {
contentReadBuffer[--p] = digits[(int) (sz % 10)];
sz /= 10;
} while (sz > 0);
contentDigest.update(contentReadBuffer, p, bufn - p);
}
contentDigest.update((byte) 0);
for (;;) {
final int r = in.read(contentReadBuffer);
if (r <= 0)
break;
contentDigest.update(contentReadBuffer, 0, r);
sz += r;
}
if (sz != length)
return zeroid;
return contentDigest.digest();
}
}
Ciao
Chris
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| Re: Eclipse JGit [message #1799409 is a reply to message #1799408] |
Thu, 06 December 2018 10:46 |
Christian Halstrick
Messages: 264
Registered: July 2009 |
Senior Member |
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sorry, example code was not cleaned. See here
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import org.eclipse.jgit.api.errors.GitAPIException;
import org.eclipse.jgit.api.errors.JGitInternalException;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.util.sha1.SHA1;
public class CalcSHA1 {
public static void main(String args[]) throws IOException, GitAPIException, JGitInternalException {
File file = new File(args[0]);
file.length();
try (InputStream in = new FileInputStream(file)) {
System.out.println(
"Git hash for file " + args[0] + " is " + ObjectId.fromRaw(computeHash(in, file.length())).getName());
}
}
private static final byte[] digits = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
protected static final byte[] zeroid = new byte[Constants.OBJECT_ID_LENGTH];
private static final byte[] hblob = Constants.encodedTypeString(Constants.OBJ_BLOB);
private static byte[] computeHash(InputStream in, long length) throws IOException {
SHA1 contentDigest = SHA1.newInstance();
final byte[] contentReadBuffer = new byte[4096];
contentDigest.update(hblob);
contentDigest.update((byte) ' ');
long sz = length;
if (sz == 0) {
contentDigest.update((byte) '0');
} else {
final int bufn = contentReadBuffer.length;
int p = bufn;
do {
contentReadBuffer[--p] = digits[(int) (sz % 10)];
sz /= 10;
} while (sz > 0);
contentDigest.update(contentReadBuffer, p, bufn - p);
}
contentDigest.update((byte) 0);
for (;;) {
final int r = in.read(contentReadBuffer);
if (r <= 0)
break;
contentDigest.update(contentReadBuffer, 0, r);
sz += r;
}
if (sz != length)
return zeroid;
return contentDigest.digest();
}
}
Ciao
Chris
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| Re: Eclipse JGit [message #1799563 is a reply to message #1799525] |
Mon, 10 December 2018 10:58 |
Christian Halstrick
Messages: 264
Registered: July 2009 |
Senior Member |
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I added crlf conversion to the java example and added a script which shows which sha1's to expect (should be 7594b8c63dc99a37e9b27e6f27e405701413d09f for both files):
> git init
Initialized empty Git repository in /tmp/init/.git/
> ls
linux.txt windows.txt
> git config core.autocrlf input
> git add linux.txt windows.txt
warning: CRLF will be replaced by LF in windows.txt.
The file will have its original line endings in your working directory
> git ls-files -sv
H 100644 7594b8c63dc99a37e9b27e6f27e405701413d09f 0 linux.txt
H 100644 7594b8c63dc99a37e9b27e6f27e405701413d09f 0 windows.txt
> git rm --cached linux.txt windows.txt
rm 'linux.txt'
rm 'windows.txt'
> git config core.autocrlf false
> git add .
> git ls-files -sv
H 100644 7594b8c63dc99a37e9b27e6f27e405701413d09f 0 linux.txt
H 100644 0be486bd774c11a47e2476daaaf082a91d7877c4 0 windows.txt
Java Code:
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import org.eclipse.jgit.api.errors.GitAPIException;
import org.eclipse.jgit.api.errors.JGitInternalException;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.util.io.AutoLFInputStream;
import org.eclipse.jgit.util.sha1.SHA1;
public class CalcSHA1 {
static byte[] buffer = new byte[4096];
private static final byte[] digits = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
protected static final byte[] zeroid = new byte[Constants.OBJECT_ID_LENGTH];
private static final byte[] hblob = Constants.encodedTypeString(Constants.OBJ_BLOB);
public static void main(String args[]) throws IOException, GitAPIException, JGitInternalException {
for (String a : args) {
File file = new File(a);
long l = 0, length = 0;
try (InputStream in = new AutoLFInputStream(new FileInputStream(file), true)) {
while ((l = in.read(buffer)) != -1) {
length += l;
}
}
try (InputStream in = new AutoLFInputStream(new FileInputStream(file), true)) {
System.out.println(
"Git hash for file " + a + " with length "+length+ " is " + ObjectId.fromRaw(computeHash(in, length)).getName());
}
}
}
private static byte[] computeHash(InputStream in, long length) throws IOException {
SHA1 contentDigest = SHA1.newInstance();
contentDigest.update(hblob);
contentDigest.update((byte) ' ');
long sz = length;
if (sz == 0) {
contentDigest.update((byte) '0');
} else {
final int bufn = buffer.length;
int p = bufn;
do {
buffer[--p] = digits[(int) (sz % 10)];
sz /= 10;
} while (sz > 0);
contentDigest.update(buffer, p, bufn - p);
}
contentDigest.update((byte) 0);
for (;;) {
final int r = in.read(buffer);
if (r <= 0)
break;
contentDigest.update(buffer, 0, r);
sz += r;
}
if (sz != length)
return zeroid;
return contentDigest.digest();
}
}
Ciao
Chris
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| Re: Eclipse JGit [message #1802687 is a reply to message #1799652] |
Thu, 14 February 2019 05:12 |
Tester Tester
Messages: 12
Registered: December 2018 |
Junior Member |
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Hi Christian,
provided solution is working fine with java 1.8. we are trying on java 1.6, but its not working due to major minor version. So, i used jgit 3.3.2 version but getting compilation error for AutoLFInputStream and SHA1 and other stuff. Do we have any alternate way to resolve this or can you backport the jgit jar for java1.6.
[Updated on: Thu, 14 February 2019 10:51] Report message to a moderator |
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