diff --git a/cgit.c b/cgit.c
index b936a70..3fc90bf 100644
--- a/cgit.c
+++ b/cgit.c
@@ -103,8 +103,7 @@ static void cgit_print_repo_page(struct cacheitem *item)
 		cgit_print_commit(cgit_query_sha1);
 		break;
 	case CMD_DIFF:
-		cgit_print_diff(cgit_query_head, cgit_query_sha1, cgit_query_sha2,
-				cgit_query_path);
+		cgit_print_diff(cgit_query_sha1, cgit_query_sha2);
 		break;
 	default:
 		cgit_print_error("Invalid request");
diff --git a/cgit.h b/cgit.h
index c276a24..bd2dd0d 100644
--- a/cgit.h
+++ b/cgit.h
@@ -207,6 +207,8 @@ extern void cgit_log_link(char *name, char *title, char *class, char *head,
 			  char *rev, char *path);
 extern void cgit_commit_link(char *name, char *title, char *class, char *head,
 			     char *rev);
+extern void cgit_diff_link(char *name, char *title, char *class, char *head,
+			   char *new_rev, char *old_rev, char *path);
 
 extern void cgit_print_error(char *msg);
 extern void cgit_print_date(time_t secs, char *format);
@@ -223,9 +225,8 @@ extern void cgit_print_summary();
 extern void cgit_print_log(const char *tip, int ofs, int cnt, char *grep, char *path, int pager);
 extern void cgit_print_blob(struct cacheitem *item, const char *hex, char *path);
 extern void cgit_print_tree(const char *rev, char *path);
-extern void cgit_print_commit(const char *hex);
-extern void cgit_print_diff(const char *head, const char *old_hex, const char *new_hex,
-			    char *path);
+extern void cgit_print_commit(char *hex);
+extern void cgit_print_diff(const char *new_hex, const char *old_hex);
 extern void cgit_print_snapshot(struct cacheitem *item, const char *hex,
 				const char *format, const char *prefix,
 				const char *filename);
diff --git a/shared.c b/shared.c
index c7cd8a5..f20fb5c 100644
--- a/shared.c
+++ b/shared.c
@@ -360,7 +360,7 @@ void cgit_diff_tree(const unsigned char *old_sha1,
 	opt.format_callback_data = fn;
 	diff_setup_done(&opt);
 
-	if (old_sha1)
+	if (old_sha1 && !is_null_sha1(old_sha1))
 		ret = diff_tree_sha1(old_sha1, new_sha1, "", &opt);
 	else
 		ret = diff_root_tree_sha1(new_sha1, "", &opt);
diff --git a/ui-commit.c b/ui-commit.c
index d489d7c..2679b59 100644
--- a/ui-commit.c
+++ b/ui-commit.c
@@ -11,6 +11,7 @@
 static int files, slots;
 static int total_adds, total_rems, max_changes;
 static int lines_added, lines_removed;
+static char *curr_rev;
 
 static struct fileinfo {
 	char status;
@@ -27,7 +28,6 @@ static struct fileinfo {
 
 void print_fileinfo(struct fileinfo *info)
 {
-	char *query, *query2;
 	char *class;
 
 	switch (info->status) {
@@ -75,24 +75,12 @@ void print_fileinfo(struct fileinfo *info)
 		html("]</span>");
 	}
 	htmlf("</td><td class='%s'>", class);
-	query = fmt("id=%s&amp;id2=%s&amp;path=%s", sha1_to_hex(info->old_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 ||
-	    info->status == DIFF_STATUS_RENAMED) {
-		html_txt(info->new_path);
-		htmlf("</a> (%s from ", info->status == DIFF_STATUS_COPIED ?
-		      "copied" : "renamed");
-		query2 = fmt("id=%s", sha1_to_hex(info->old_sha1));
-		html_link_open(cgit_pageurl(cgit_query_repo, "view", query2),
-			       NULL, NULL);
-		html_txt(info->old_path);
-		html("</a>)");
-	} else {
-		html_txt(info->new_path);
-		html("</a>");
-	}
+	cgit_tree_link(info->new_path, NULL, NULL, cgit_query_head, curr_rev,
+		       info->new_path);
+	if (info->status == DIFF_STATUS_COPIED || info->status == DIFF_STATUS_RENAMED)
+		htmlf(" (%s from %s)",
+		      info->status == DIFF_STATUS_COPIED ? "copied" : "renamed",
+		      info->old_path);
 	html("</td><td class='right'>");
 	htmlf("%d", info->added + info->removed);
 	html("</td><td class='graph'>");
@@ -145,19 +133,19 @@ void inspect_filepair(struct diff_filepair *pair)
 }
 
 
-void cgit_print_commit(const char *hex)
+void cgit_print_commit(char *hex)
 {
 	struct commit *commit, *parent;
 	struct commitinfo *info;
 	struct commit_list *p;
 	unsigned char sha1[20];
-	char *query;
 	char *filename;
 	char *tmp;
 	int i;
 
 	if (!hex)
 		hex = cgit_query_head;
+	curr_rev = hex;
 
 	if (get_sha1(hex, sha1)) {
 		cgit_print_error(fmt("Bad object id: %s", hex));
@@ -202,11 +190,10 @@ void cgit_print_commit(const char *hex)
 		     "<td colspan='2' class='sha1'>");
 		cgit_commit_link(sha1_to_hex(p->item->object.sha1), NULL, NULL,
 				 cgit_query_head, sha1_to_hex(p->item->object.sha1));
-		html(" (<a href='");
-		query = fmt("id=%s&amp;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>");
+		html(" (");
+		cgit_diff_link("diff", NULL, NULL, cgit_query_head, hex,
+			       sha1_to_hex(p->item->object.sha1), NULL);
+		html(")</td></tr>");
 	}
 	if (cgit_repo->snapshots) {
 		htmlf("<tr><th>download</th><td colspan='2' class='sha1'><a href='");
@@ -233,10 +220,9 @@ void cgit_print_commit(const char *hex)
 		html("<div class='diffstat-summary'>");
 		htmlf("%d files changed, %d insertions, %d deletions (",
 		      files, total_adds, total_rems);
-		query = fmt("h=%s", hex);
-		html_link_open(cgit_pageurl(cgit_query_repo, "diff", query), NULL, NULL);
-		html("show diff</a>)");
-		html("</div>");
+		cgit_diff_link("show diff", NULL, NULL, cgit_query_head, hex,
+			       NULL, NULL);
+		html(")</div>");
 	}
 	cgit_free_commitinfo(info);
 }
diff --git a/ui-diff.c b/ui-diff.c
index 5c864d9..a76a234 100644
--- a/ui-diff.c
+++ b/ui-diff.c
@@ -89,54 +89,52 @@ static void filepair_cb(struct diff_filepair *pair)
 		cgit_print_error("Error running diff");
 }
 
-void cgit_print_diff(const char *head, const char *old_hex, const char *new_hex, char *path)
+void cgit_print_diff(const char *new_rev, const char *old_rev)
 {
 	unsigned char sha1[20], sha2[20];
 	enum object_type type;
 	unsigned long size;
-	struct commit *commit;
+	struct commit *commit, *commit2;
 
-	html("<table class='diff'>");
-	html("<tr><td>");
-
-	if (head && !old_hex && !new_hex) {
-		get_sha1(head, sha1);
-		commit = lookup_commit_reference(sha1);
-		if (commit && !parse_commit(commit))
-			cgit_diff_commit(commit, filepair_cb);
-		else
-			cgit_print_error(fmt("Bad commit: %s", head));
-		html("</td></tr>");
-		html("</table>");
+	if (!new_rev)
+		new_rev = cgit_query_head;
+	get_sha1(new_rev, sha1);
+	type = sha1_object_info(sha1, &size);
+	if (type == OBJ_BAD) {
+		cgit_print_error(fmt("Bad object name: %s", new_rev));
+		return;
+	}
+	if (type != OBJ_COMMIT) {
+		cgit_print_error(fmt("Unhandled object type: %s",
+				     typename(type)));
 		return;
 	}
 
-	get_sha1(old_hex, sha1);
-	get_sha1(new_hex, sha2);
+	commit = lookup_commit_reference(sha1);
+	if (!commit || parse_commit(commit))
+		cgit_print_error(fmt("Bad commit: %s", sha1_to_hex(sha1)));
 
-	type = sha1_object_info(sha1, &size);
-	if (type == OBJ_BAD) {
+	if (old_rev)
+		get_sha1(old_rev, sha2);
+	else if (commit->parents && commit->parents->item)
+		hashcpy(sha2, commit->parents->item->object.sha1);
+	else
+		hashclr(sha2);
+
+	if (!is_null_sha1(sha2)) {
 		type = sha1_object_info(sha2, &size);
 		if (type == OBJ_BAD) {
-			cgit_print_error(fmt("Bad object names: %s, %s", old_hex, new_hex));
+			cgit_print_error(fmt("Bad object name: %s", sha1_to_hex(sha2)));
 			return;
 		}
+		commit2 = lookup_commit_reference(sha2);
+		if (!commit2 || parse_commit(commit2))
+			cgit_print_error(fmt("Bad commit: %s", sha1_to_hex(sha2)));
 	}
 
-	switch(type) {
-	case OBJ_BLOB:
-		header(sha1, path, 0644, sha2, path, 0644);
-		if (cgit_diff_files(sha1, sha2, print_line))
-			cgit_print_error("Error running diff");
-		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("<table class='diff'>");
+	html("<tr><td>");
+	cgit_diff_tree(sha2, sha1, filepair_cb);
 	html("</td></tr>");
 	html("</table>");
 }
diff --git a/ui-shared.c b/ui-shared.c
index 71c899a..15d8254 100644
--- a/ui-shared.c
+++ b/ui-shared.c
@@ -176,6 +176,28 @@ void cgit_commit_link(char *name, char *title, char *class, char *head,
 	reporevlink("commit", name, title, class, head, rev, NULL);
 }
 
+void cgit_diff_link(char *name, char *title, char *class, char *head,
+		    char *new_rev, char *old_rev, char *path)
+{
+	char *delim;
+
+	delim = repolink(title, class, "diff", head, path);
+	if (new_rev && strcmp(new_rev, cgit_query_head)) {
+		html(delim);
+		html("id=");
+		html_attr(new_rev);
+		delim = "&amp;";
+	}
+	if (old_rev) {
+		html(delim);
+		html("id2=");
+		html_attr(old_rev);
+	}
+	html("'>");
+	html_txt(name);
+	html("</a>");
+}
+
 void cgit_print_date(time_t secs, char *format)
 {
 	char buf[64];