untracked cache: avoid racy timestamps

diff --git a/diffcore-rename.c b/diffcore-rename.c
index 4e132f1fdb68ed3c930ca8224a5403c9b406cc3b..af1fe08861e6862985ac8fb9311b17568cb9e547 100644 (file)
--- a/diffcore-rename.c
+++ b/diffcore-rename.c
@@ -15,8 +15,7 @@ static struct diff_rename_dst {
 } *rename_dst;
 static int rename_dst_nr, rename_dst_alloc;
 
-static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two,
-                                                int insert_ok)
+static int find_rename_dst(struct diff_filespec *two)
 {
        int first, last;
 
@@ -27,16 +26,33 @@ static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two,
                struct diff_rename_dst *dst = &(rename_dst[next]);
                int cmp = strcmp(two->path, dst->two->path);
                if (!cmp)
-                       return dst;
+                       return next;
                if (cmp < 0) {
                        last = next;
                        continue;
                }
                first = next+1;
        }
-       /* not found */
-       if (!insert_ok)
-               return NULL;
+       return -first - 1;
+}
+
+static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two)
+{
+       int ofs = find_rename_dst(two);
+       return ofs < 0 ? NULL : &rename_dst[ofs];
+}
+
+/*
+ * Returns 0 on success, -1 if we found a duplicate.
+ */
+static int add_rename_dst(struct diff_filespec *two)
+{
+       int first = find_rename_dst(two);
+
+       if (first >= 0)
+               return -1;
+       first = -first - 1;
+
        /* insert to make it at "first" */
        ALLOC_GROW(rename_dst, rename_dst_nr + 1, rename_dst_alloc);
        rename_dst_nr++;
@@ -46,7 +62,7 @@ static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two,
        rename_dst[first].two = alloc_filespec(two->path);
        fill_filespec(rename_dst[first].two, two->sha1, two->sha1_valid, two->mode);
        rename_dst[first].pair = NULL;
-       return &(rename_dst[first]);
+       return 0;
 }
 
 /* Table of rename/copy src files */
@@ -450,8 +466,12 @@ void diffcore_rename(struct diff_options *options)
                        else if (!DIFF_OPT_TST(options, RENAME_EMPTY) &&
                                 is_empty_blob_sha1(p->two->sha1))
                                continue;
-                       else
-                               locate_rename_dst(p->two, 1);
+                       else if (add_rename_dst(p->two) < 0) {
+                               warning("skipping rename detection, detected"
+                                       " duplicate destination '%s'",
+                                       p->two->path);
+                               goto cleanup;
+                       }
                }
                else if (!DIFF_OPT_TST(options, RENAME_EMPTY) &&
                         is_empty_blob_sha1(p->one->sha1))
@@ -582,8 +602,7 @@ void diffcore_rename(struct diff_options *options)
                         * We would output this create record if it has
                         * not been turned into a rename/copy already.
                         */
-                       struct diff_rename_dst *dst =
-                               locate_rename_dst(p->two, 0);
+                       struct diff_rename_dst *dst = locate_rename_dst(p->two);
                        if (dst && dst->pair) {
                                diff_q(&outq, dst->pair);
                                pair_to_free = p;
@@ -613,8 +632,7 @@ void diffcore_rename(struct diff_options *options)
                         */
                        if (DIFF_PAIR_BROKEN(p)) {
                                /* broken delete */
-                               struct diff_rename_dst *dst =
-                                       locate_rename_dst(p->one, 0);
+                               struct diff_rename_dst *dst = locate_rename_dst(p->one);
                                if (dst && dst->pair)
                                        /* counterpart is now rename/copy */
                                        pair_to_free = p;