1 files changed, 35 insertions, 0 deletions

diff --git a/ui-diff.c b/ui-diff.c
index 1cf2ce0..caebd5d 100644
--- a/ui-diff.c
+++ b/ui-diff.c
@@ -36,6 +36,7 @@ static struct fileinfo {
 
 static int use_ssdiff = 0;
 static struct diff_filepair *current_filepair;
+static const char *current_prefix;
 
 struct diff_filespec *cgit_get_current_old_file(void)
 {
@@ -132,11 +133,30 @@ static void count_diff_lines(char *line, int len)
         }
 }
 
+static int show_filepair(struct diff_filepair *pair)
+{
+        /* Always show if we have no limiting prefix. */
+        if (!current_prefix)
+                return 1;
+
+        /* Show if either path in the pair begins with the prefix. */
+        if (starts_with(pair->one->path, current_prefix) ||
+            starts_with(pair->two->path, current_prefix))
+                return 1;
+
+        /* Otherwise we don't want to show this filepair. */
+        return 0;
+}
+
 static void inspect_filepair(struct diff_filepair *pair)
 {
         int binary = 0;
         unsigned long old_size = 0;
         unsigned long new_size = 0;
+
+        if (!show_filepair(pair))
+                return;
+
         files++;
         lines_added = 0;
         lines_removed = 0;
@@ -279,6 +299,9 @@ static void filepair_cb(struct diff_filepair *pair)
         int binary = 0;
         linediff_fn print_line_fn = print_line;
 
+        if (!show_filepair(pair))
+                return;
+
         current_filepair = pair;
         if (use_ssdiff) {
                 cgit_ssdiff_header_begin();
@@ -365,6 +388,18 @@ void cgit_print_diff(const char *new_rev, const char *old_rev,
         const unsigned char *old_tree_sha1, *new_tree_sha1;
         diff_type difftype;
 
+        /*
+         * If "follow" is set then the diff machinery needs to examine the
+         * entire commit to detect renames so we must limit the paths in our
+         * own callbacks and not pass the prefix to the diff machinery.
+         */
+        if (ctx.qry.follow && ctx.cfg.enable_follow_links) {
+                current_prefix = prefix;
+                prefix = "";
+        } else {
+                current_prefix = NULL;
+        }
+
         if (!new_rev)
                 new_rev = ctx.qry.head;
         if (get_sha1(new_rev, new_rev_sha1)) {