Change merge-cache and git-merge-one-file to use the SHA1 of the file

instead of a checked-out temporary copy.

If merging requires a checked-out-copy, we now do so with "unpack-file".

git-merge-one-file-script

@@ -2,34 +2,50 @@
 #
 # This is the git merge script, called with
 #
-#   $1 - original file (or empty string)
-#   $2 - file in branch1 (or empty string)
-#   $3 - file in branch2 (or empty string)
+#   $1 - original file SHA1 (or empty)
+#   $2 - file in branch1 SHA1 (or empty)
+#   $3 - file in branch2 SHA1 (or empty)
 #   $4 - pathname in repository
 #
 #
-# Case 1: file removed in both
+# Handle some trivial cases.. The _really_ trivial cases have
+# been handled already by read-tree, but that one doesn't
+# do any merges that migth change the tree layout
 #
-if [ -z "$2$3" ]; then
-	rm -- "$4"
-	update-cache --remove -- "$4"
-	exit 0
-fi
+
+case "${1:-.}${2:-.}${3:-.}" in
 #
-# Case 2: file exists in just one
+# deleted in both, or deleted in one and unchanged in the other
 #
-if [ "$2$3" == "$3$2" ]; then
-	cat "$2$3" > "$4"
-	update-cache --add -- "$4"
+"$1.." | "$1.$1" | "$1$1.")
+	rm -f -- "$4"
+	update-cache --remove -- "$4"
 	exit 0
-fi
+	;;
+
 #
-# Case 3: file exists in both
+# added in one, or added identically in both
 #
-src="$1"
-if [ -z "$1" ]; then
-	src=/dev/null
-fi	
-echo "Auto-merging $4"
-cp "$3" "$4"
-merge "$4" "$src" "$2" && update-cache --add -- "$4"
+".$2." | "..$3" | ".$2$2")
+	mv $(unpack-file "${2:-$3}") $4
+	update-cache --add -- $4
+	exit 0
+	;;
+
+#
+# Modified in both, but differently ;(
+#
+"$1$2$3")
+	echo "Auto-merging $4"
+	orig=$(unpack-file $1)
+	src1=$(unpack-file $2)
+	src2=$(unpack-file $3)
+	merge "$src2" "$orig" "$src1" || echo Leaving conflict merge in $src2 && exit 1
+	cp "$src2" "$4" && update-cache --add -- "$4" && exit 0
+	;;
+
+*)
+	echo "Not handling case $1 -> $2 -> $3"
+	;;
+esac
+exit 1

merge-cache.c

@@ -25,29 +25,6 @@ static void run_program(void)
 		die("merge program failed");
 }
 
-static char *create_temp_file(int stage, unsigned char *sha1)
-{
-	static char template[4][50];
-	char *path = template[stage];
-	void *buf;
-	char type[100];
-	unsigned long size;
-	int fd;
-
-	buf = read_sha1_file(sha1, type, &size);
-	if (!buf || strcmp(type, "blob"))
-		die("unable to read blob object %s", sha1_to_hex(sha1));
-
-	strcpy(path, ".merge_file_XXXXXX");
-	fd = mkstemp(path);
-	if (fd < 0)
-		die("unable to create temp-file");
-	if (write(fd, buf, size) != size)
-		die("unable to write temp-file");
-	close(fd);
-	return path;
-}
-
 static int merge_entry(int pos, const char *path)
 {
 	int found;
@@ -61,13 +38,15 @@ static int merge_entry(int pos, const char *path)
 	arguments[4] = path;
 	found = 0;
 	do {
+		static char hexbuf[4][60];
 		struct cache_entry *ce = active_cache[pos];
 		int stage = ce_stage(ce);
 
 		if (strcmp(ce->name, path))
 			break;
 		found++;
-		arguments[stage] = create_temp_file(stage, ce->sha1);
+		strcpy(hexbuf[stage], sha1_to_hex(ce->sha1));
+		arguments[stage] = hexbuf[stage];
 	} while (++pos < active_nr);
 	if (!found)
 		die("merge-cache: %s not in the cache", path);