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, 61 insertions, 8 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>");
+	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>");
 }