Merge "Process most in-core merges without local temp files"

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

@@ -44,6 +44,9 @@
  */
 package org.eclipse.jgit.merge;
 
+import static org.eclipse.jgit.lib.Constants.CHARACTER_ENCODING;
+import static org.eclipse.jgit.lib.Constants.OBJ_BLOB;
+
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
@@ -76,7 +79,6 @@ import org.eclipse.jgit.errors.MissingObjectException;
 import org.eclipse.jgit.errors.NoWorkTreeException;
 import org.eclipse.jgit.internal.JGitText;
 import org.eclipse.jgit.lib.ConfigConstants;
-import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.FileMode;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.ObjectReader;
@@ -89,6 +91,7 @@ import org.eclipse.jgit.treewalk.TreeWalk;
 import org.eclipse.jgit.treewalk.WorkingTreeIterator;
 import org.eclipse.jgit.util.FS;
 import org.eclipse.jgit.util.FileUtils;
+import org.eclipse.jgit.util.TemporaryBuffer;
 
 /**
  * A three-way merger performing a content-merge if necessary
@@ -756,90 +759,92 @@ public class ResolveMerger extends ThreeWayMerger {
 			CanonicalTreeParser ours, CanonicalTreeParser theirs,
 			MergeResult<RawText> result) throws FileNotFoundException,
 			IOException {
-		File of = writeMergedFile(result);
+		File mergedFile = !inCore ? writeMergedFile(result) : null;
 		if (result.containsConflicts()) {
-			// a conflict occurred, the file will contain conflict markers
-			// the index will be populated with the three stages and only the
-			// workdir (if used) contains the halfways merged content
+			// A conflict occurred, the file will contain conflict markers
+			// the index will be populated with the three stages and the
+			// workdir (if used) contains the halfway merged content.
 			add(tw.getRawPath(), base, DirCacheEntry.STAGE_1, 0, 0);
 			add(tw.getRawPath(), ours, DirCacheEntry.STAGE_2, 0, 0);
 			add(tw.getRawPath(), theirs, DirCacheEntry.STAGE_3, 0, 0);
 			mergeResults.put(tw.getPathString(), result);
-		} else {
-			// no conflict occurred, the file will contain fully merged content.
-			// the index will be populated with the new merged version
-			DirCacheEntry dce = new DirCacheEntry(tw.getPathString());
-			int newMode = mergeFileModes(tw.getRawMode(0), tw.getRawMode(1),
-					tw.getRawMode(2));
-			// set the mode for the new content. Fall back to REGULAR_FILE if
-			// you can't merge modes of OURS and THEIRS
-			dce.setFileMode((newMode == FileMode.MISSING.getBits()) ? FileMode.REGULAR_FILE
-					: FileMode.fromBits(newMode));
-			dce.setLastModified(of.lastModified());
-			dce.setLength((int) of.length());
-			InputStream is = new FileInputStream(of);
+			return;
+		}
+
+		// No conflict occurred, the file will contain fully merged content.
+		// The index will be populated with the new merged version.
+		DirCacheEntry dce = new DirCacheEntry(tw.getPathString());
+
+		// Set the mode for the new content. Fall back to REGULAR_FILE if
+		// we can't merge modes of OURS and THEIRS.
+		int newMode = mergeFileModes(
+				tw.getRawMode(0),
+				tw.getRawMode(1),
+				tw.getRawMode(2));
+		dce.setFileMode(newMode == FileMode.MISSING.getBits()
+				? FileMode.REGULAR_FILE
+				: FileMode.fromBits(newMode));
+		if (mergedFile != null) {
+			long len = mergedFile.length();
+			dce.setLastModified(mergedFile.lastModified());
+			dce.setLength((int) len);
+			InputStream is = new FileInputStream(mergedFile);
 			try {
-				dce.setObjectId(getObjectInserter().insert(
-				    Constants.OBJ_BLOB, of.length(), is));
+				dce.setObjectId(getObjectInserter().insert(OBJ_BLOB, len, is));
 			} finally {
 				is.close();
-				if (inCore)
-					FileUtils.delete(of);
 			}
-			builder.add(dce);
-		}
+		} else
+			dce.setObjectId(insertMergeResult(result));
+		builder.add(dce);
 	}
 
 	/**
-	 * Writes merged file content to the working tree. In case {@link #inCore}
-	 * is set and we don't have a working tree the content is written to a
-	 * temporary file
+	 * Writes merged file content to the working tree.
 	 *
 	 * @param result
 	 *            the result of the content merge
-	 * @return the file to which the merged content was written
+	 * @return the working tree file to which the merged content was written.
 	 * @throws FileNotFoundException
 	 * @throws IOException
 	 */
 	private File writeMergedFile(MergeResult<RawText> result)
 			throws FileNotFoundException, IOException {
-		MergeFormatter fmt = new MergeFormatter();
-		File of = null;
-		FileOutputStream fos;
-		if (!inCore) {
-			File workTree = db.getWorkTree();
-			if (workTree == null)
-				// TODO: This should be handled by WorkingTreeIterators which
-				// support write operations
-				throw new UnsupportedOperationException();
-
-			FS fs = db.getFS();
-			of = new File(workTree, tw.getPathString());
-			File parentFolder = of.getParentFile();
-			if (!fs.exists(parentFolder))
-				parentFolder.mkdirs();
-			fos = new FileOutputStream(of);
-			try {
-				fmt.formatMerge(fos, result, Arrays.asList(commitNames),
-						Constants.CHARACTER_ENCODING);
-			} finally {
-				fos.close();
-			}
-		} else if (!result.containsConflicts()) {
-			// When working inCore, only trivial merges can be handled,
-			// so we generate objects only in conflict free cases
-			of = File.createTempFile("merge_", "_temp", null); //$NON-NLS-1$ //$NON-NLS-2$
-			fos = new FileOutputStream(of);
-			try {
-				fmt.formatMerge(fos, result, Arrays.asList(commitNames),
-						Constants.CHARACTER_ENCODING);
-			} finally {
-				fos.close();
-			}
+		File workTree = db.getWorkTree();
+		if (workTree == null)
+			// TODO: This should be handled by WorkingTreeIterators which
+			// support write operations
+			throw new UnsupportedOperationException();
+
+		FS fs = db.getFS();
+		File of = new File(workTree, tw.getPathString());
+		File parentFolder = of.getParentFile();
+		if (!fs.exists(parentFolder))
+			parentFolder.mkdirs();
+		FileOutputStream fos = new FileOutputStream(of);
+		try {
+			new MergeFormatter().formatMerge(fos, result,
+					Arrays.asList(commitNames), CHARACTER_ENCODING);
+		} finally {
+			fos.close();
 		}
 		return of;
 	}
 
+	private ObjectId insertMergeResult(MergeResult<RawText> result)
+			throws IOException {
+		TemporaryBuffer.LocalFile buf = new TemporaryBuffer.LocalFile(10 << 20);
+		try {
+			new MergeFormatter().formatMerge(buf, result,
+					Arrays.asList(commitNames), CHARACTER_ENCODING);
+			buf.close();
+			return getObjectInserter().insert(OBJ_BLOB, buf.length(),
+					buf.openInputStream());
+		} finally {
+			buf.destroy();
+		}
+	}
+
 	/**
 	 * Try to merge filemodes. If only ours or theirs have changed the mode
 	 * (compared to base) we choose that one. If ours and theirs have equal
@@ -872,7 +877,7 @@ public class ResolveMerger extends ThreeWayMerger {
 			throws IOException {
 		if (id.equals(ObjectId.zeroId()))
 			return new RawText(new byte[] {});
-		return new RawText(db.open(id, Constants.OBJ_BLOB).getCachedBytes());
+		return new RawText(db.open(id, OBJ_BLOB).getCachedBytes());
 	}
 
 	private static boolean nonTree(final int mode) {