Thread (1 message) 1 message, 1 author, 2016-06-15

Re: [PATCH v3 07/18] rerere: stop looping unnecessarily

From: Junio C Hamano <hidden>
Date: 2016-06-15 23:05:52

Junio C Hamano [off-list ref] writes:
quoted hunk
handle_cache() loops 3 times starting from an index entry that is
unmerged, while ignoring an entry for a path that is different from
what we are looking for.

As the index is sorted, once we see a different path, we know we saw
all stages for the path we are interested in.  Just loop while we
see the same path and then break, instead of continuing for 3 times.

Signed-off-by: Junio C Hamano <redacted>
---
 rerere.c | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)
diff --git a/rerere.c b/rerere.c
index 4c45f55..7b1419c 100644
--- a/rerere.c
+++ b/rerere.c
@@ -329,24 +329,21 @@ static int handle_cache(const char *path, unsigned char *sha1, const char *outpu
 		return -1;
 	pos = -pos - 1;
 
-	for (i = 0; i < 3; i++) {
+	while (pos < active_nr) {
 		enum object_type type;
 		unsigned long size;
-		int j;
 
-		if (active_nr <= pos)
-			break;
 		ce = active_cache[pos++];
 		if (ce_namelen(ce) != len || memcmp(ce->name, path, len))
-			continue;
-		j = ce_stage(ce) - 1;
-		mmfile[j].ptr = read_sha1_file(ce->sha1, &type, &size);
-		mmfile[j].size = size;
+			break;
+		i = ce_stage(ce) - 1;
+		mmfile[i].ptr = read_sha1_file(ce->sha1, &type, &size);
+		mmfile[i].size = size;
If the conflicted index has multiple stage #1 entries, this will leak
what was previously read.  As the array is initialized to NULLs, perhaps


	i = ce_stage(ce) - 1;
        if (!mmfile[i].ptr) {
		mmfile[i].ptr = read_sha1_file(ce->sha1, &type, &size);
                mmfile[i].size = size;
	}

should be sufficient.  This does change the semantics, in that we
used to use the last stage #1 entry as the common ancestor when
doing the plain-vanilla three-way merge, but with the leak fix, we
will use the first stage #1 entry.  But it does not change it in
any meaningful way---we are using only one of multiple stage #1
entries arbitrarily picked either way.
 	}
-	for (i = 0; i < 3; i++) {
+	for (i = 0; i < 3; i++)
 		if (!mmfile[i].ptr && !mmfile[i].size)
 			mmfile[i].ptr = xstrdup("");
-	}
+
 	/*
 	 * NEEDSWORK: handle conflicts from merges with
 	 * merge.renormalize set, too
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