[PATCH] ui-diff: Add configuration option to limit number of files

[Tim Nordell]

If a large commit is made, the generated HTML file can be very
large and take the server a while to generate the HTML for the
diff.  Add a configuration option to limit the maximum number
of files presented within a diff.

Signed-off-by: Tim Nordell <tim.nordell at logicpd.com>

diff --git a/cgit.c b/cgit.c
index 0ca1baa..87ba811 100644
--- a/cgit.c
+++ b/cgit.c
@@ -248,6 +248,12 @@ static void config_cb(const char *name, const char *value)
 		ctx.cfg.max_blob_size = atoi(value);
 	else if (!strcmp(name, "max-repo-count"))
 		ctx.cfg.max_repo_count = atoi(value);
+	else if (!strcmp(name, "max-diff-files"))
+	{
+		ctx.cfg.max_diff_files = atoi(value);
+		if(ctx.cfg.max_diff_files < 1)
+			ctx.cfg.max_diff_files = INT_MAX;
+	}
 	else if (!strcmp(name, "max-commit-count"))
 		ctx.cfg.max_commit_count = atoi(value);
 	else if (!strcmp(name, "project-list"))
@@ -401,6 +407,7 @@ static void prepare_context(void)
 	ctx.cfg.enable_tree_linenumbers = 1;
 	ctx.cfg.enable_git_config = 0;
 	ctx.cfg.max_repo_count = 50;
+	ctx.cfg.max_diff_files = INT_MAX;
 	ctx.cfg.max_commit_count = 50;
 	ctx.cfg.max_lock_attempts = 5;
 	ctx.cfg.max_msg_len = 80;
diff --git a/cgit.h b/cgit.h
index 350d25d..b2b2ae9 100644
--- a/cgit.h
+++ b/cgit.h
@@ -243,6 +243,7 @@ struct cgit_config {
 	int enable_git_config;
 	int local_time;
 	int max_atom_items;
+	int max_diff_files;
 	int max_repo_count;
 	int max_commit_count;
 	int max_lock_attempts;
diff --git a/cgitrc.5.txt b/cgitrc.5.txt
index 94901bd..3bca0ab 100644
--- a/cgitrc.5.txt
+++ b/cgitrc.5.txt
@@ -420,6 +420,14 @@ side-by-side-diffs::
 	If set to "1" shows side-by-side diffs instead of unidiffs per
 	default. Default value: "0".
 
+max-diff-files::
+	This value controls the maximum number of files presented in a diff
+	view to help control the size of HTML files presented in a web browser.
+	(In a very large commit, a client web browser may choke on a large
+	commit, such as the first commit in the Linux kernel repository.)
+	A value of "0" turns this feature off.
+	Default value: "0".
+
 snapshots::
 	Text which specifies the default set of snapshot formats that cgit
 	generates links for. The value is a space-separated list of zero or
diff --git a/ui-diff.c b/ui-diff.c
index 52ed942..65045a4 100644
--- a/ui-diff.c
+++ b/ui-diff.c
@@ -18,6 +18,7 @@ unsigned char new_rev_sha1[20];
 static int files, slots;
 static int total_adds, total_rems, max_changes;
 static int lines_added, lines_removed;
+static int filepair_cnt;
 
 static struct fileinfo {
 	char status;
@@ -206,8 +207,18 @@ static void cgit_print_diffstat(const unsigned char *old_sha1,
 	max_changes = 0;
 	cgit_diff_tree(old_sha1, new_sha1, inspect_filepair, prefix,
 		       ctx.qry.ignorews);
-	for (i = 0; i<files; i++)
+	for (i = 0; i<files && i < ctx.cfg.max_diff_files; i++)
 		print_fileinfo(&items[i]);
+	/* If needed, add a row indicating that we didn't display everything */
+	if(i < files)
+	{
+		html("<tr>");
+		html("<td class='mode'>...</td>");
+		html("<td class='upd'>...</td>");
+		html("<td class='right'>...</td>");
+		html("<td class='graph'>...</td>");
+		html("</tr>");
+	}
 	html("</table>");
 	html("<div class='diffstat-summary'>");
 	htmlf("%d files changed, %d insertions, %d deletions",
@@ -302,6 +313,11 @@ static void filepair_cb(struct diff_filepair *pair)
 	if (!show_filepair(pair))
 		return;
 
+	if(filepair_cnt++ >= ctx.cfg.max_diff_files)
+	{
+		return;
+	}
+
 	current_filepair = pair;
 	if (use_ssdiff) {
 		cgit_ssdiff_header_begin();
@@ -490,6 +506,7 @@ void cgit_print_diff(const char *new_rev, const char *old_rev,
 		html("<table summary='diff' class='diff'>");
 		html("<tr><td>");
 	}
+        filepair_cnt = 0;
 	cgit_diff_tree(old_rev_sha1, new_rev_sha1, filepair_cb, prefix,
 		       ctx.qry.ignorews);
 	if (!use_ssdiff)
-- 
2.4.9