ui-log: Fix filecount/linecount when path limit is in effect

When using ui-log with path limits, the listing of commits enables parent
rewriting in Git's internal log machinery. This did not work well together
with cgit_diff_commit() which is used to generate the filecount and
linecount numbers for each commit in the log view. cgit_diff_commit() would
operate without any path limits, and would therefore process the full diff
between the commits shown (which, because of parent rewriting, is not the
same as processing the diff for the commit itself). Additionally, the bottom
commit in the log view would (again, because of parent rewriting) have zero
parents, causing us to process the entire diff between the empty tree and
that commit. Since path limits were not in effect, this would (in large
projects) reports thousands of files and millions of lines changed in that
bottom commit.

This patch fixes the issue by applying the same path limit to
cgit_diff_commit() as is applied to the rest of the log view. The result is
that the filecount/linecount now only reflects the diff as it pertains to
the given path limit.

Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Lars Hjemli <hjemli@gmail.com>

cgit.h

@@ -294,7 +294,8 @@ extern void cgit_diff_tree(const unsigned char *old_sha1,
 			   const unsigned char *new_sha1,
 			   filepair_fn fn, const char *prefix, int ignorews);
 
-extern void cgit_diff_commit(struct commit *commit, filepair_fn fn);
+extern void cgit_diff_commit(struct commit *commit, filepair_fn fn,
+			     const char *prefix);
 
 __attribute__((format (printf,1,2)))
 extern char *fmt(const char *format,...);

shared.c

@@ -338,13 +338,13 @@ void cgit_diff_tree(const unsigned char *old_sha1,
 	diff_flush(&opt);
 }
 
-void cgit_diff_commit(struct commit *commit, filepair_fn fn)
+void cgit_diff_commit(struct commit *commit, filepair_fn fn, const char *prefix)
 {
 	unsigned char *old_sha1 = NULL;
 
 	if (commit->parents)
 		old_sha1 = commit->parents->item->object.sha1;
-	cgit_diff_tree(old_sha1, commit->object.sha1, fn, NULL,
+	cgit_diff_tree(old_sha1, commit->object.sha1, fn, prefix,
 		       ctx.qry.ignorews);
 }
 

ui-log.c

@@ -101,7 +101,7 @@ void print_commit(struct commit *commit)
 		files = 0;
 		add_lines = 0;
 		rem_lines = 0;
-		cgit_diff_commit(commit, inspect_files);
+		cgit_diff_commit(commit, inspect_files, ctx.qry.vpath);
 		html("</td><td>");
 		htmlf("%d", files);
 		if (ctx.repo->enable_log_linecount) {