Add cgit_diff_link()

This adds a new function used to generate links to the diff page and uses
it everywhere such links appear (expect for single files in the diffstat
displayed on the commit page: this is now a link to the tree page).

The updated diff-page now expects zero, one or two revision specifiers, in
parameters head, id and id2. Id defaults to head unless otherwise specified,
while head (as usual) defaults to repo.defbranch. If id2 isn't specified, it
defaults to the first parent of id1.

The most important change is of course that now all repo pages (summary, log,
tree, commit and diff) has support for passing on the current branch and
revision, i.e. the road is now open for a 'static' menu with links to all
of these pages.

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

1 files changed, 31 insertions, 33 deletions

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>");
 }