Add support for cloning over http

This patch implements basic support for cloning over http, based on the
work on git-http-backend by Shawn O. Pearce.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

Makefile

@@ -56,6 +56,7 @@ OBJECTS += html.o
 OBJECTS += parsing.o
 OBJECTS += shared.o
 OBJECTS += ui-blob.o
+OBJECTS += ui-clone.o
 OBJECTS += ui-commit.o
 OBJECTS += ui-diff.o
 OBJECTS += ui-log.o

cmd.c

@@ -11,6 +11,7 @@
 #include "cache.h"
 #include "ui-shared.h"
 #include "ui-blob.h"
+#include "ui-clone.h"
 #include "ui-commit.h"
 #include "ui-diff.h"
 #include "ui-log.h"
@@ -22,6 +23,11 @@
 #include "ui-tag.h"
 #include "ui-tree.h"
 
+static void HEAD_fn(struct cgit_context *ctx)
+{
+	cgit_clone_head(ctx);
+}
+
 static void about_fn(struct cgit_context *ctx)
 {
 	if (ctx->repo)
@@ -45,6 +51,11 @@ static void diff_fn(struct cgit_context *ctx)
 	cgit_print_diff(ctx->qry.sha1, ctx->qry.sha2, ctx->qry.path);
 }
 
+static void info_fn(struct cgit_context *ctx)
+{
+	cgit_clone_info(ctx);
+}
+
 static void log_fn(struct cgit_context *ctx)
 {
 	cgit_print_log(ctx->qry.sha1, ctx->qry.ofs, ctx->cfg.max_commit_count,
@@ -59,6 +70,11 @@ static void ls_cache_fn(struct cgit_context *ctx)
 	cache_ls(ctx->cfg.cache_root);
 }
 
+static void objects_fn(struct cgit_context *ctx)
+{
+	cgit_clone_objects(ctx);
+}
+
 static void repolist_fn(struct cgit_context *ctx)
 {
 	cgit_print_repolist();
@@ -102,12 +118,15 @@ static void tree_fn(struct cgit_context *ctx)
 struct cgit_cmd *cgit_get_cmd(struct cgit_context *ctx)
 {
 	static struct cgit_cmd cmds[] = {
+		def_cmd(HEAD, 1, 0),
 		def_cmd(about, 0, 1),
 		def_cmd(blob, 1, 0),
 		def_cmd(commit, 1, 1),
 		def_cmd(diff, 1, 1),
+		def_cmd(info, 1, 0),
 		def_cmd(log, 1, 1),
 		def_cmd(ls_cache, 0, 0),
+		def_cmd(objects, 1, 0),
 		def_cmd(patch, 1, 0),
 		def_cmd(refs, 1, 1),
 		def_cmd(repolist, 0, 0),

html.c

@@ -51,6 +51,13 @@ void htmlf(const char *format, ...)
 	html(buf);
 }
 
+void html_status(int code, int more_headers)
+{
+	htmlf("Status: %d\n", code);
+	if (!more_headers)
+		html("\n");
+}
+
 void html_txt(char *txt)
 {
 	char *t = txt;

html.h

@@ -5,6 +5,7 @@ extern int htmlfd;
 
 extern void html(const char *txt);
 extern void htmlf(const char *format,...);
+extern void html_status(int code, int more_headers);
 extern void html_txt(char *txt);
 extern void html_ntxt(int len, char *txt);
 extern void html_attr(char *txt);

ui-clone.c

@@ -0,0 +1,104 @@
+/* ui-clone.c: functions for http cloning, based on
+ * git's http-backend.c by Shawn O. Pearce
+ *
+ * Copyright (C) 2008 Lars Hjemli
+ *
+ * Licensed under GNU General Public License v2
+ *   (see COPYING for full license text)
+ */
+
+#include "cgit.h"
+#include "html.h"
+#include "ui-shared.h"
+
+static int print_ref_info(const char *refname, const unsigned char *sha1,
+                          int flags, void *cb_data)
+{
+	struct object *obj;
+
+	if (!(obj = parse_object(sha1)))
+		return 0;
+
+	if (!strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/"))
+		htmlf("%s\t%s\n", sha1_to_hex(sha1), refname);
+	else if (!prefixcmp(refname, "refs/tags") && obj->type == OBJ_TAG) {
+		if (!(obj = deref_tag(obj, refname, 0)))
+			return 0;
+		htmlf("%s\t%s\n", sha1_to_hex(sha1), refname);
+		htmlf("%s\t%s^{}\n", sha1_to_hex(obj->sha1), refname);
+	}
+	return 0;
+}
+
+static void print_pack_info(struct cgit_context *ctx)
+{
+	struct packed_git *pack;
+	int ofs;
+
+	ctx->page.mimetype = "text/plain";
+	ctx->page.filename = "objects/info/packs";
+	cgit_print_http_headers(ctx);
+	ofs = strlen(ctx->repo->path) + strlen("/objects/pack/");
+	prepare_packed_git();
+	for (pack = packed_git; pack; pack = pack->next)
+		if (pack->pack_local)
+			htmlf("P %s\n", pack->pack_name + ofs);
+}
+
+static void send_file(struct cgit_context *ctx, char *path)
+{
+	struct stat st;
+	int err;
+
+	if (stat(path, &st)) {
+		switch (errno) {
+		case ENOENT:
+			err = 404;
+			break;
+		case EACCES:
+			err = 403;
+			break;
+		default:
+			err = 400;
+		}
+		html_status(err, 0);
+		return;
+	}
+	ctx->page.mimetype = "application/octet-stream";
+	ctx->page.filename = path;
+	if (prefixcmp(ctx->repo->path, path))
+		ctx->page.filename += strlen(ctx->repo->path) + 1;
+	cgit_print_http_headers(ctx);
+	html_include(path);
+}
+
+void cgit_clone_info(struct cgit_context *ctx)
+{
+	if (!ctx->qry.path || strcmp(ctx->qry.path, "refs"))
+		return;
+
+	ctx->page.mimetype = "text/plain";
+	ctx->page.filename = "info/refs";
+	cgit_print_http_headers(ctx);
+	for_each_ref(print_ref_info, ctx);
+}
+
+void cgit_clone_objects(struct cgit_context *ctx)
+{
+	if (!ctx->qry.path) {
+		html_status(400, 0);
+		return;
+	}
+
+	if (!strcmp(ctx->qry.path, "info/packs")) {
+		print_pack_info(ctx);
+		return;
+	}
+
+	send_file(ctx, git_path("objects/%s", ctx->qry.path));
+}
+
+void cgit_clone_head(struct cgit_context *ctx)
+{
+	send_file(ctx, git_path("%s", "HEAD"));
+}

ui-clone.h

@@ -0,0 +1,8 @@
+#ifndef UI_CLONE_H
+#define UI_CLONE_H
+
+void cgit_clone_info(struct cgit_context *ctx);
+void cgit_clone_objects(struct cgit_context *ctx);
+void cgit_clone_head(struct cgit_context *ctx);
+
+#endif /* UI_CLONE_H */