Add graphical diffstat to commit view

The diffstat is calculated against the leftmost parent of the commit. This
gives nice information for "normal" merges while octopus merges are less
than optimal, so the diffstat isn't calculated for those merges.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

5 files changed, 128 insertions, 31 deletions

diff --git a/Makefile b/Makefile
index ccc7582..ea4d818 100644
--- a/Makefile
+++ b/Makefile
@@ -52,12 +52,13 @@ git/libgit.a:
 # phony targets
 #
 install: all clean-cache
 	mkdir -p $(prefix)
 	install cgit $(prefix)/cgit.cgi
 	install cgit.css $(prefix)/cgit.css
+	install add.png del.png $(prefix)/
 
 clean-cgit:
 	rm -f cgit *.o
 
 distclean-cgit: clean-cgit
 	git clean -d -x
diff --git a/add.png b/add.png
new file mode 100644
index 0000000..c550388
--- a/dev/null
+++ b/add.png
diff --git a/cgit.css b/cgit.css
index cded981..b736b19 100644
--- a/cgit.css
+++ b/cgit.css
@@ -23,12 +23,19 @@ h2 {
 h3 {
 	margin-top: 0em;
 	font-size: 100%;
 	font-weight: normal;
 }
 
+h4 {
+	margin-top: 1.5em;
+	margin-bottom: 0.1em;
+	font-size: 100%;
+	font-weight: bold;
+}
+
 a {
 	color: blue;
 	text-decoration: none;
 }
 
 a:hover {
@@ -224,25 +231,34 @@ div.commit-msg {
 	font-family: monospace;
 }
 
 table.diffstat {
 	border-collapse: collapse;
 	margin-top: 1.5em;
+	width: 100%;
+	border: solid 1px #aaa;
+}
+
+table.diffstat tr:hover {
+	background-color: #eee;
 }
 
 table.diffstat th {
 	font-weight: normal;
 	text-align: left;
 	text-decoration: underline;
 	padding: 0.1em 1em 0.1em 0.1em;
 	font-size: 100%;
 }
 
 table.diffstat td {
-	padding: 0.1em 1em 0.1em 0.1em;
+	padding: 0.2em 0.2em 0.1em 0.1em;
 	font-size: 100%;
+	border: none;
+	border-top: solid 1px #aaa;
+	border-bottom: solid 1px #aaa;
 }
 
 table.diffstat td span.modechange {
 	padding-left: 1em;
 	color: red;
 }
@@ -256,13 +272,23 @@ table.diffstat td.del a {
 }
 
 table.diffstat td.upd a {
 	color: blue;
 }
 
-table.diffstat td.summary {
+table.diffstat td.graph {
+	width: 75%;
+	vertical-align: center;
+}
+
+table.diffstat td.graph img {
+	border: none;
+	height: 11pt;
+}
+
+div.diffstat-summary {
 	color: #888;
 	padding-top: 0.5em;
 }
 
 table.diff td {
 	border: solid 1px black;
diff --git a/del.png b/del.png
new file mode 100644
index 0000000..5c73e82
--- a/dev/null
+++ b/del.png
diff --git a/ui-commit.c b/ui-commit.c
index f1a22d3..ce33cf9 100644
--- a/ui-commit.c
+++ b/ui-commit.c
@@ -5,20 +5,36 @@
  * Licensed under GNU General Public License v2
  *   (see COPYING for full license text)
  */
 
 #include "cgit.h"
 
-int files = 0;
+int files = 0, slots = 0;
+int total_adds = 0, total_rems = 0, max_changes = 0;
+int lines_added, lines_removed;
 
-void print_filepair(struct diff_filepair *pair)
+struct fileinfo {
+	char status;
+	unsigned char old_sha1[20];
+	unsigned char new_sha1[20];
+	unsigned short old_mode;
+	unsigned short new_mode;
+	char *old_path;
+	char *new_path;
+	unsigned int added;
+	unsigned int removed;
+} *items;
+
+
+void print_fileinfo(struct fileinfo *info)
 {
-	char *query;
+	char *query, *query2;
 	char *class;
+	double width;
 
-	switch (pair->status) {
+	switch (info->status) {
 	case DIFF_STATUS_ADDED:
 		class = "add";
 		break;
 	case DIFF_STATUS_COPIED:
 		class = "cpy";
 		break;
@@ -38,65 +54,113 @@ void print_filepair(struct diff_filepair *pair)
 		class = "unk";
 		break;
 	case DIFF_STATUS_UNMERGED:
 		class = "stg";
 		break;
 	default:
-		die("bug: unhandled diff status %c", pair->status);
+		die("bug: unhandled diff status %c", info->status);
 	}
 
 	html("<tr>");
 	htmlf("<td class='mode'>");
-	if (is_null_sha1(pair->two->sha1)) {
-		html_filemode(pair->one->mode);
+	if (is_null_sha1(info->new_sha1)) {
+		html_filemode(info->old_mode);
 	} else {
-		html_filemode(pair->two->mode);
+		html_filemode(info->new_mode);
 	}
 
-	if (pair->one->mode != pair->two->mode &&
-	    !is_null_sha1(pair->one->sha1) &&
-	    !is_null_sha1(pair->two->sha1)) {
+	if (info->old_mode != info->new_mode &&
+	    !is_null_sha1(info->old_sha1) &&
+	    !is_null_sha1(info->new_sha1)) {
 		html("<span class='modechange'>[");
-		html_filemode(pair->one->mode);
+		html_filemode(info->old_mode);
 		html("]</span>");
 	}
 	htmlf("</td><td class='%s'>", class);
-	query = fmt("id=%s&id2=%s", sha1_to_hex(pair->one->sha1),
-		    sha1_to_hex(pair->two->sha1));
+	query = fmt("id=%s&id2=%s", sha1_to_hex(info->old_sha1),
+		    sha1_to_hex(info->new_sha1));
 	html_link_open(cgit_pageurl(cgit_query_repo, "diff", query),
 		       NULL, NULL);
-	if (pair->status == DIFF_STATUS_COPIED ||
-	    pair->status == DIFF_STATUS_RENAMED) {
-		html_txt(pair->two->path);
-		htmlf("</a> (%s from ", pair->status == DIFF_STATUS_COPIED ?
+	if (info->status == DIFF_STATUS_COPIED ||
+	    info->status == DIFF_STATUS_RENAMED) {
+		html_txt(info->new_path);
+		htmlf("</a> (%s from ", info->status == DIFF_STATUS_COPIED ?
 		      "copied" : "renamed");
-		query = fmt("id=%s", sha1_to_hex(pair->one->sha1));
-		html_link_open(cgit_pageurl(cgit_query_repo, "view", query),
+		query2 = fmt("id=%s", sha1_to_hex(info->old_sha1));
+		html_link_open(cgit_pageurl(cgit_query_repo, "view", query2),
 			       NULL, NULL);
-		html_txt(pair->one->path);
+		html_txt(info->old_path);
 		html("</a>)");
 	} else {
-		html_txt(pair->two->path);
+		html_txt(info->new_path);
 		html("</a>");
 	}
-	html("<td>");
+	html("</td><td class='right'>");
+	htmlf("%d", info->added + info->removed);
 
-	//TODO: diffstat graph
+	html("</td><td class='graph'>");
+	width = (info->added + info->removed) * 100.0 / max_changes;
+	if (width < 0.1)
+		width = 0.1;
+	html_link_open(cgit_pageurl(cgit_query_repo, "diff", query),
+		       NULL, NULL);
+	htmlf("<img src='/cgit/add.png' style='width: %.1f%%;'/>",
+	      info->added * width / (info->added + info->removed));
+	htmlf("<img src='/cgit/del.png' style='width: %.1f%%;'/>",
+	      info->removed * width / (info->added + info->removed));
+	html("</a></td></tr>\n");
+}
 
-	html("</td></tr>\n");
+void cgit_count_diff_lines(char *line, int len)
+{
+	if (line && (len > 0)) {
+		if (line[0] == '+')
+			lines_added++;
+		else if (line[0] == '-')
+			lines_removed++;
+	}
+}
+
+void inspect_filepair(struct diff_filepair *pair)
+{
 	files++;
+	lines_added = 0;
+	lines_removed = 0;
+	cgit_diff_files(pair->one->sha1, pair->two->sha1, cgit_count_diff_lines);
+	if (files >= slots) {
+		if (slots == 0)
+			slots = 4;
+		else
+			slots = slots * 2;
+		items = xrealloc(items, slots * sizeof(struct fileinfo));
 }
+	items[files-1].status = pair->status;
+	hashcpy(items[files-1].old_sha1, pair->one->sha1);
+	hashcpy(items[files-1].new_sha1, pair->two->sha1);
+	items[files-1].old_mode = pair->one->mode;
+	items[files-1].new_mode = pair->two->mode;
+	items[files-1].old_path = xstrdup(pair->one->path);
+	items[files-1].new_path = xstrdup(pair->two->path);
+	items[files-1].added = lines_added;
+	items[files-1].removed = lines_removed;
+	if (lines_added + lines_removed > max_changes)
+		max_changes = lines_added + lines_removed;
+	total_adds += lines_added;
+	total_rems += lines_removed;
+}
+
 
 void cgit_print_commit(const char *hex)
 {
 	struct commit *commit;
 	struct commitinfo *info;
 	struct commit_list *p;
 	unsigned char sha1[20];
 	char *query;
 	char *filename;
+	int i;
 
 	if (get_sha1(hex, sha1)) {
 		cgit_print_error(fmt("Bad object id: %s", hex));
 		return;
 	}
 	commit = lookup_commit_reference(sha1);
@@ -145,14 +209,20 @@ void cgit_print_commit(const char *hex)
 	html("<div class='commit-subject'>");
 	html_txt(info->subject);
 	html("</div>");
 	html("<div class='commit-msg'>");
 	html_txt(info->msg);
 	html("</div>");
+	if (!(commit->parents && commit->parents->next && commit->parents->next->next)) {
 	html("<table class='diffstat'>");
-	html("<tr><th colspan='3'>Affected files</tr>\n");
-	cgit_diff_commit(commit, print_filepair);
-	htmlf("<tr><td colspan='3' class='summary'>"
-	      "%d file%s changed</td></tr>\n", files, files > 1 ? "s" : "");
+		max_changes = 0;
+		cgit_diff_commit(commit, inspect_filepair);
+		for(i = 0; i<files; i++)
+			print_fileinfo(&items[i]);
 	html("</table>");
+		html("<div class='diffstat-summary'>");
+		htmlf("%d files changed, %d insertions, %d deletions\n",
+		      files, total_adds, total_rems);
+		html("</div>");
+	}
 	cgit_free_commitinfo(info);
 }