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>

5 files changed, 63 insertions, 10 deletions

diff --git a/cgit.c b/cgit.c
index aee7ba3..3d85a08 100644
--- a/cgit.c
+++ b/cgit.c
@@ -118,3 +118,3 @@ static void cgit_print_repo_page(struct cacheitem *item)
         } 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 {
diff --git a/cgit.css b/cgit.css
index b736b19..fe0ba50 100644
--- a/cgit.css
+++ b/cgit.css
@@ -292,2 +292,7 @@ div.diffstat-summary {
 
+table.diff th {
+        padding: 1em 0em 0.1em 0.1em;
+        text-align: left;
+}
+
 table.diff td {
diff --git a/cgit.h b/cgit.h
index 46f3173..93699b5 100644
--- a/cgit.h
+++ b/cgit.h
@@ -176,3 +176,3 @@ 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, 
diff --git a/ui-commit.c b/ui-commit.c
index ce33cf9..b3d1c28 100644
--- a/ui-commit.c
+++ b/ui-commit.c
@@ -78,4 +78,4 @@ void print_fileinfo(struct fileinfo *info)
         htmlf("</td><td class='%s'>", class);
-        query = fmt("id=%s&id2=%s", sha1_to_hex(info->old_sha1),
-                    sha1_to_hex(info->new_sha1));
+        query = fmt("id=%s&id2=%s&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),
@@ -153,3 +153,3 @@ void cgit_print_commit(const char *hex)
 {
-        struct commit *commit;
+        struct commit *commit, *parent;
         struct commitinfo *info;
@@ -192,2 +192,9 @@ void cgit_print_commit(const char *hex)
               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>"
@@ -197,4 +204,8 @@ void cgit_print_commit(const char *hex)
                 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>");
         }
diff --git a/ui-diff.c b/ui-diff.c
index 96106af..10330d3 100644
--- a/ui-diff.c
+++ b/ui-diff.c
@@ -33,5 +33,18 @@ static void print_line(char *line, int len)
 
-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;
 
@@ -40,5 +53,29 @@ void cgit_print_diff(const char *old_hex, const char *new_hex)
 
-        html("<table class='diff'><tr><td>");
-        if (cgit_diff_files(sha1, sha2, print_line))
-                cgit_print_error("Error running diff");
+        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>");