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
@@ -95,49 +95,49 @@ static void cgit_print_repo_page(struct cacheitem *item)
                 show_search = 1;
 
         cgit_print_docstart(title, item);
 
 
         if (!cgit_query_page) {
                 cgit_print_pageheader("summary", show_search);
                 cgit_print_summary();
                 cgit_print_docend();
                 return;
         }
 
         cgit_print_pageheader(cgit_query_page, show_search);
 
         if (!strcmp(cgit_query_page, "log")) {
                 cgit_print_log(cgit_query_head, cgit_query_ofs,
                                cgit_max_commit_count, cgit_query_search);
         } else if (!strcmp(cgit_query_page, "tree")) {
                 cgit_print_tree(cgit_query_sha1, cgit_query_path);
         } else if (!strcmp(cgit_query_page, "commit")) {
                 cgit_print_commit(cgit_query_sha1);
         } 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_print_docend();
 }
 
 static void cgit_fill_cache(struct cacheitem *item, int use_cache)
 {
         static char buf[PATH_MAX];
         int stdout2;
 
         getcwd(buf, sizeof(buf));
         item->st.st_mtime = time(NULL);
 
         if (use_cache) {
                 stdout2 = chk_positive(dup(STDOUT_FILENO), 
                                        "Preserving STDOUT");
                 chk_zero(close(STDOUT_FILENO), "Closing STDOUT");
                 chk_positive(dup2(item->fd, STDOUT_FILENO), "Dup2(cachefile)");
         }
 
         if (cgit_query_repo)
                 cgit_print_repo_page(item);
         else
diff --git a/cgit.css b/cgit.css
index b736b19..fe0ba50 100644
--- a/cgit.css
+++ b/cgit.css
@@ -269,48 +269,53 @@ table.diffstat td.add a {
 
 table.diffstat td.del a {
         color: red;
 }
 
 table.diffstat td.upd a {
         color: blue;
 }
 
 table.diffstat td.graph {
         width: 75%;
         vertical-align: center;
 }
 
 table.diffstat td.graph img {
         border: none;
         height: 11pt;
 }
 
 div.diffstat-summary {
         color: #888;
         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;
         white-space: pre;
 }
 
 table.diff td div.hunk {
         background: #ccc;
 }
 
 table.diff td div.add {
         color: green;
 }
 
 table.diff td div.del {
         color: red;
 }
 
 .sha1 {
         font-family: courier;
         font-size: 90%;
 }
 
 .left {
diff --git a/cgit.h b/cgit.h
index 46f3173..93699b5 100644
--- a/cgit.h
+++ b/cgit.h
@@ -153,30 +153,30 @@ extern int cache_unlock(struct cacheitem *item);
 extern int cache_cancel_lock(struct cacheitem *item);
 extern int cache_exist(struct cacheitem *item);
 extern int cache_expired(struct cacheitem *item);
 
 extern char *cgit_repourl(const char *reponame);
 extern char *cgit_pageurl(const char *reponame, const char *pagename, 
                           const char *query);
 
 extern void cgit_print_error(char *msg);
 extern void cgit_print_date(unsigned long secs);
 extern void cgit_print_docstart(char *title, struct cacheitem *item);
 extern void cgit_print_docend();
 extern void cgit_print_pageheader(char *title, int show_search);
 extern void cgit_print_snapshot_start(const char *mimetype, 
                                       const char *filename, 
                                       struct cacheitem *item);
 
 extern void cgit_print_repolist(struct cacheitem *item);
 extern void cgit_print_summary();
 extern void cgit_print_log(const char *tip, int ofs, int cnt, char *grep);
 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);
 
 #endif /* CGIT_H */
diff --git a/ui-commit.c b/ui-commit.c
index ce33cf9..b3d1c28 100644
--- a/ui-commit.c
+++ b/ui-commit.c
@@ -55,50 +55,50 @@ void print_fileinfo(struct fileinfo *info)
                 break;
         case DIFF_STATUS_UNMERGED:
                 class = "stg";
                 break;
         default:
                 die("bug: unhandled diff status %c", info->status);
         }
 
         html("<tr>");
         htmlf("<td class='mode'>");
         if (is_null_sha1(info->new_sha1)) {
                 html_filemode(info->old_mode);
         } else {
                 html_filemode(info->new_mode);
         }
 
         if (info->old_mode != info->new_mode &&
             !is_null_sha1(info->old_sha1) &&
             !is_null_sha1(info->new_sha1)) {
                 html("<span class='modechange'>[");
                 html_filemode(info->old_mode);
                 html("]</span>");
         }
         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),
                        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>");
         }
         html("</td><td class='right'>");
         htmlf("%d", info->added + info->removed);
 
         html("</td><td class='graph'>");
         width = (info->added + info->removed) * 100.0 / max_changes;
         if (width < 0.1)
                 width = 0.1;
         html_link_open(cgit_pageurl(cgit_query_repo, "diff", query),
@@ -130,94 +130,105 @@ void inspect_filepair(struct diff_filepair *pair)
                 if (slots == 0)
                         slots = 4;
                 else
                         slots = slots * 2;
                 items = xrealloc(items, slots * sizeof(struct fileinfo));
         }
         items[files-1].status = pair->status;
         hashcpy(items[files-1].old_sha1, pair->one->sha1);
         hashcpy(items[files-1].new_sha1, pair->two->sha1);
         items[files-1].old_mode = pair->one->mode;
         items[files-1].new_mode = pair->two->mode;
         items[files-1].old_path = xstrdup(pair->one->path);
         items[files-1].new_path = xstrdup(pair->two->path);
         items[files-1].added = lines_added;
         items[files-1].removed = lines_removed;
         if (lines_added + lines_removed > max_changes)
                 max_changes = lines_added + lines_removed;
         total_adds += lines_added;
         total_rems += lines_removed;
 }
 
 
 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];
         char *query;
         char *filename;
         int i;
 
         if (get_sha1(hex, sha1)) {
                 cgit_print_error(fmt("Bad object id: %s", hex));
                 return;
         }
         commit = lookup_commit_reference(sha1);
         if (!commit) {
                 cgit_print_error(fmt("Bad commit reference: %s", hex));
                 return;
         }
         info = cgit_parse_commit(commit);
 
         html("<table class='commit-info'>\n");
         html("<tr><th>author</th><td>");
         html_txt(info->author);
         html(" ");
         html_txt(info->author_email);
         html("</td><td class='right'>");
         cgit_print_date(info->author_date);
         html("</td></tr>\n");
         html("<tr><th>committer</th><td>");
         html_txt(info->committer);
         html(" ");
         html_txt(info->committer_email);
         html("</td><td class='right'>");
         cgit_print_date(info->committer_date);
         html("</td></tr>\n");
         html("<tr><th>tree</th><td colspan='2' class='sha1'><a href='");
         query = fmt("id=%s", sha1_to_hex(commit->tree->object.sha1));
         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='");
                 filename = fmt("%s-%s.zip", cgit_query_repo, hex);
                 html_attr(cgit_pageurl(cgit_query_repo, "snapshot",
                                        fmt("id=%s&name=%s", hex, filename)));
                 htmlf("'>%s</a></td></tr>", filename);
         }
         html("</table>\n");
         html("<div class='commit-subject'>");
         html_txt(info->subject);
         html("</div>");
         html("<div class='commit-msg'>");
         html_txt(info->msg);
         html("</div>");
         if (!(commit->parents && commit->parents->next && commit->parents->next->next)) {
                 html("<table class='diffstat'>");
                 max_changes = 0;
                 cgit_diff_commit(commit, inspect_filepair);
                 for(i = 0; i<files; i++)
                         print_fileinfo(&items[i]);
                 html("</table>");
                 html("<div class='diffstat-summary'>");
                 htmlf("%d files changed, %d insertions, %d deletions\n",
diff --git a/ui-diff.c b/ui-diff.c
index 96106af..10330d3 100644
--- a/ui-diff.c
+++ b/ui-diff.c
@@ -10,36 +10,73 @@
 
 
 /*
  * print a single line returned from xdiff
  */
 static void print_line(char *line, int len)
 {
         char *class = "ctx";
         char c = line[len-1];
 
         if (line[0] == '+')
                 class = "add";
         else if (line[0] == '-')
                 class = "del";
         else if (line[0] == '@')
                 class = "hunk";
 
         htmlf("<div class='%s'>", class);
         line[len-1] = '\0';
         html_txt(line);
         html("</div>");
         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>");
-        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>");
 }