ui-tree: render folder README under the directory listing

When browsing a tree, detect the best README (readme[.md/.markdown/.mkd/
.rst/.txt] or bare, case-insensitive, most-preferred extension wins) among
the directory entries and render it through the about-filter beneath the
file list, GitHub-style. The filter gets the readme path as argv[1] so the
md2html relative-link rewriting resolves against the readme dir.

1 files changed, 54 insertions, 4 deletions

diff --git a/ui-tree.c b/ui-tree.c
index 5ac8c9a..fd174b5 100644
--- a/ui-tree.c
+++ b/ui-tree.c
@@ -11,14 +11,51 @@
 #include "cgit.h"
 #include "ui-tree.h"
 #include "html.h"
+#include "ui-blob.h"
 #include "ui-shared.h"
 
 struct walk_tree_context {
 	char *curr_rev;
 	char *match_path;
 	int state;
+	/* Best README found in the directory currently being listed, so we can
+	 * render it (GitHub-style) under the file list. */
+	char *readme_path;
+	int readme_rank;
 };
 
+/* Rank a directory entry as a renderable README: 0 = not a readme, higher =
+ * more preferred. "readme" + a known extension, case-insensitive. */
+static int readme_rank(const char *name)
+{
+	static const char * const exts[] = {
+		"", ".txt", ".rst", ".mkd", ".mdown", ".markdown", ".md"
+	};
+	const char *rest;
+	int i;
+
+	if (strncasecmp(name, "readme", 6))
+		return 0;
+	rest = name + 6;
+	for (i = ARRAY_SIZE(exts) - 1; i >= 0; i--)
+		if (!strcasecmp(rest, exts[i]))
+			return i + 1;
+	return 0;
+}
+
+/* Render the best README of the just-listed directory through the about-filter,
+ * so browsing a tree shows the folder's readme beneath the listing. */
+static void print_dir_readme(struct walk_tree_context *walk_tree_ctx)
+{
+	if (!walk_tree_ctx->readme_path || !ctx.repo->about_filter)
+		return;
+	html("<div id='summary' class='dir-readme'>");
+	cgit_open_filter(ctx.repo->about_filter, walk_tree_ctx->readme_path);
+	cgit_print_file(walk_tree_ctx->readme_path, walk_tree_ctx->curr_rev, 1);
+	cgit_close_filter(ctx.repo->about_filter);
+	html("</div>\n");
+}
+
 static void print_text_buffer(const char *name, char *buf, unsigned long size)
 {
 	unsigned long lineno, idx;
@@ -216,6 +253,15 @@ static int ls_item(const struct object_id *oid, struct strbuf *base,
 	strbuf_addf(&fullpath, "%s%s%s", ctx.qry.path ? ctx.qry.path : "",
 		    ctx.qry.path ? "/" : "", name);
 
+	if (S_ISREG(mode)) {
+		int rank = readme_rank(name);
+		if (rank > walk_tree_ctx->readme_rank) {
+			walk_tree_ctx->readme_rank = rank;
+			free(walk_tree_ctx->readme_path);
+			walk_tree_ctx->readme_path = xstrdup(fullpath.buf);
+		}
+	}
+
 	if (!S_ISGITLINK(mode)) {
 		type = odb_read_object_info(the_repository->objects, oid, &size);
 		if (type == OBJ_BAD) {
@@ -293,9 +339,10 @@ static void ls_head(void)
 	html("</tr>\n");
 }
 
-static void ls_tail(void)
+static void ls_tail(struct walk_tree_context *walk_tree_ctx)
 {
 	html("</table>\n");
+	print_dir_readme(walk_tree_ctx);
 	cgit_print_layout_end();
 }
 
@@ -315,7 +362,7 @@ static void ls_tree(const struct object_id *oid, const char *path, struct walk_t
 
 	ls_head();
 	read_tree(the_repository, tree, &paths, ls_item, walk_tree_ctx);
-	ls_tail();
+	ls_tail(walk_tree_ctx);
 }
 
 
@@ -368,7 +415,9 @@ void cgit_print_tree(const char *rev, char *path)
 	};
 	struct walk_tree_context walk_tree_ctx = {
 		.match_path = path,
-		.state = 0
+		.state = 0,
+		.readme_path = NULL,
+		.readme_rank = 0
 	};
 
 	if (!rev)
@@ -396,7 +445,7 @@ void cgit_print_tree(const char *rev, char *path)
 	read_tree(the_repository, repo_get_commit_tree(the_repository, commit),
 		  &paths, walk_tree, &walk_tree_ctx);
 	if (walk_tree_ctx.state == 1)
-		ls_tail();
+		ls_tail(&walk_tree_ctx);
 	else if (walk_tree_ctx.state == 2)
 		cgit_print_layout_end();
 	else
@@ -404,4 +453,5 @@ void cgit_print_tree(const char *rev, char *path)
 
 cleanup:
 	free(walk_tree_ctx.curr_rev);
+	free(walk_tree_ctx.readme_path);
 }