Add commitdiff between commit and each of it's parent

A link is added next to each parent of a commit, leading to the new
diff-functionality in ui-diff.c.

Also added support for a path-parameter to filelevel diffs accessed via the
diffstat.

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

cgit.c

@@ -116,7 +116,7 @@ static void cgit_print_repo_page(struct cacheitem *item)
 	} else if (!strcmp(cgit_query_page, "view")) {
 		cgit_print_view(cgit_query_sha1, cgit_query_path);
 	} else if (!strcmp(cgit_query_page, "diff")) {
-		cgit_print_diff(cgit_query_sha1, cgit_query_sha2);
+		cgit_print_diff(cgit_query_sha1, cgit_query_sha2, cgit_query_path);
 	} else {
 		cgit_print_error("Invalid request");
 	}

cgit.css

@@ -290,6 +290,11 @@ div.diffstat-summary {
 	padding-top: 0.5em;
 }
 
+table.diff th {
+	padding: 1em 0em 0.1em 0.1em;
+	text-align: left;
+}
+
 table.diff td {
 	border: solid 1px black;
 	font-family: monospace;

cgit.h

@@ -174,7 +174,7 @@ extern void cgit_print_view(const char *hex, char *path);
 extern void cgit_print_blob(struct cacheitem *item, const char *hex, char *path);
 extern void cgit_print_tree(const char *hex, char *path);
 extern void cgit_print_commit(const char *hex);
-extern void cgit_print_diff(const char *old_hex, const char *new_hex);
+extern void cgit_print_diff(const char *old_hex, const char *new_hex, char *path);
 extern void cgit_print_snapshot(struct cacheitem *item, const char *hex, 
 				const char *format, const char *prefix,
 				const char *filename);

ui-commit.c

@@ -76,8 +76,8 @@ void print_fileinfo(struct fileinfo *info)
 		html("]</span>");
 	}
 	htmlf("</td><td class='%s'>", class);
-	query = fmt("id=%s&id2=%s", sha1_to_hex(info->old_sha1),
+	query = fmt("id=%s&id2=%s&path=%s", sha1_to_hex(info->old_sha1),
-		    sha1_to_hex(info->new_sha1));
+		    sha1_to_hex(info->new_sha1), info->new_path);
 	html_link_open(cgit_pageurl(cgit_query_repo, "diff", query),
 		       NULL, NULL);
 	if (info->status == DIFF_STATUS_COPIED ||
@@ -151,7 +151,7 @@ void inspect_filepair(struct diff_filepair *pair)
 
 void cgit_print_commit(const char *hex)
 {
-	struct commit *commit;
+	struct commit *commit, *parent;
 	struct commitinfo *info;
 	struct commit_list *p;
 	unsigned char sha1[20];
@@ -190,13 +190,24 @@ void cgit_print_commit(const char *hex)
 	html_attr(cgit_pageurl(cgit_query_repo, "tree", query));
 	htmlf("'>%s</a></td></tr>\n", sha1_to_hex(commit->tree->object.sha1));
       	for (p = commit->parents; p ; p = p->next) {
+		parent = lookup_commit_reference(p->item->object.sha1);
+		if (!parent) {
+			html("<tr><td colspan='3'>");
+			cgit_print_error("Error reading parent commit");
+			html("</td></tr>");
+			continue;
+		}
 		html("<tr><th>parent</th>"
 		     "<td colspan='2' class='sha1'>"
 		     "<a href='");
 		query = fmt("id=%s", sha1_to_hex(p->item->object.sha1));
 		html_attr(cgit_pageurl(cgit_query_repo, "commit", query));
-		htmlf("'>%s</a></td></tr>\n",
+		htmlf("'>%s</a> (<a href='",
 		      sha1_to_hex(p->item->object.sha1));
+		query = fmt("id=%s&id2=%s", sha1_to_hex(parent->tree->object.sha1),
+			    sha1_to_hex(commit->tree->object.sha1));
+		html_attr(cgit_pageurl(cgit_query_repo, "diff", query));
+		html("'>diff</a>)</td></tr>");
 	}
 	if (cgit_repo->snapshots) {
 		htmlf("<tr><th>download</th><td colspan='2' class='sha1'><a href='");

ui-diff.c

@@ -31,15 +31,52 @@ static void print_line(char *line, int len)
 	line[len-1] = c;
 }
 
-void cgit_print_diff(const char *old_hex, const char *new_hex)
+static void filepair_cb(struct diff_filepair *pair)
+{
+	html("<tr><th>");
+	html_txt(pair->two->path);
+	html("</th></tr>");
+	html("<tr><td>");
+	if (cgit_diff_files(pair->one->sha1, pair->two->sha1, print_line))
+		cgit_print_error("Error running diff");
+	html("</tr></td>");
+}
+
+void cgit_print_diff(const char *old_hex, const char *new_hex, char *path)
 {
 	unsigned char sha1[20], sha2[20];
+	enum object_type type;
+	unsigned long size;
 
 	get_sha1(old_hex, sha1);
 	get_sha1(new_hex, sha2);
 
-	html("<table class='diff'><tr><td>");
+	type = sha1_object_info(sha1, &size);
+	if (type == OBJ_BAD) {
+		type = sha1_object_info(sha2, &size);
+		if (type == OBJ_BAD) {
+			cgit_print_error(fmt("Bad object names: %s, %s", old_hex, new_hex));
+			return;
+		}
+	}
+
+	html("<table class='diff'>");
+	switch(type) {
+	case OBJ_BLOB:
+		if (path)
+			htmlf("<tr><th>%s</th></tr>", path);
+		html("<tr><td>");
 		if (cgit_diff_files(sha1, sha2, print_line))
 			cgit_print_error("Error running diff");
+		html("</tr></td>");
+		break;
+	case OBJ_TREE:
+		cgit_diff_tree(sha1, sha2, filepair_cb);
+		break;
+	default:
+		cgit_print_error(fmt("Unhandled object type: %s",
+				     typename(type)));
+		break;
+	}
 	html("</td></tr></table>");
 }