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>

6 files changed, 75 insertions, 69 deletions

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];