Fix index blob for merges with CRLF translations

Commit fc7d407 corrected line endings for working tree files resulting
from merges when CRLF translations are to be done. However, that also
resulted in the file content being put as-is into the index, which is
wrong. The index must contain the file content with reverse CRLF
translations applied.

With core.autocrlf=true, the working tree file should have CR-LF, but
the index blob must still contain only LF.

Fix this oversight and apply the inverse translation when updating the
index, similar to what is done in AddCommand.

Bug: 499615
Change-Id: I3a33931318bdb580b2390f3450f91ea8f258a6a4
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>

org.eclipse.jgit.test/tst/org/eclipse/jgit/merge/ResolveMergerTest.java

@@ -414,6 +414,9 @@ public class ResolveMergerTest extends RepositoryTestCase {
 		assertEquals(MergeResult.MergeStatus.MERGED,
 				mergeResult.getMergeStatus());
 		checkFile(testFile, "a first line\r\na crlf file\r\na second line\r\n");
+		assertEquals(
+				"[crlf.txt, mode:100644, content:a first line\na crlf file\na second line\n]",
+				indexState(CONTENT));
 	}
 
 	/**

org.eclipse.jgit/src/org/eclipse/jgit/merge/ResolveMerger.java

@@ -51,6 +51,7 @@ import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_ALGORITHM;
 import static org.eclipse.jgit.lib.Constants.CHARACTER_ENCODING;
 import static org.eclipse.jgit.lib.Constants.OBJ_BLOB;
 
+import java.io.BufferedInputStream;
 import java.io.BufferedOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
@@ -903,17 +904,54 @@ public class ResolveMerger extends ThreeWayMerger {
 			long len = mergedFile.length();
 			dce.setLastModified(FS.DETECTED.lastModified(mergedFile));
 			dce.setLength((int) len);
-			InputStream is = new FileInputStream(mergedFile);
-			try {
-				dce.setObjectId(getObjectInserter().insert(OBJ_BLOB, len, is));
-			} finally {
-				is.close();
+			EolStreamType streamType = EolStreamTypeUtil.detectStreamType(
+					OperationType.CHECKIN_OP, workingTreeOptions,
+					tw.getAttributes());
+			long blobLen = len == 0 ? 0
+					: getEntryContentLength(mergedFile, streamType);
+			// TODO: we read the file twice because insert() needs the blob
+			// length up front. C.f. AddCommand.
+			try (InputStream is = EolStreamTypeUtil.wrapInputStream(
+					new FileInputStream(mergedFile), streamType)) {
+				dce.setObjectId(
+						getObjectInserter().insert(OBJ_BLOB, blobLen, is));
 			}
 		} else
 			dce.setObjectId(insertMergeResult(result));
 		builder.add(dce);
 	}
 
+	/**
+	 * Computes the length of the index blob for a given file.
+	 *
+	 * @param file
+	 *            on disk
+	 * @param streamType
+	 *            specifying CRLF translation
+	 * @return the number of bytes after CRLF translations have been done.
+	 * @throws IOException
+	 *             if the file cannot be read
+	 */
+	private long getEntryContentLength(File file, EolStreamType streamType)
+			throws IOException {
+		if (streamType == EolStreamType.DIRECT) {
+			return file.length();
+		}
+		long length = 0;
+		try (InputStream is = EolStreamTypeUtil.wrapInputStream(
+				new BufferedInputStream(new FileInputStream(file)),
+				streamType)) {
+			for (;;) {
+				long n = is.skip(1 << 20);
+				if (n <= 0) {
+					break;
+				}
+				length += n;
+			}
+			return length;
+		}
+	}
+
 	/**
 	 * Writes merged file content to the working tree.
 	 *