1 files changed, 276 insertions, 4 deletions

diff --git a/remote-curl.c b/remote-curl.c
index 8d2ffaf..68e7b1c 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -1,6 +1,7 @@
 #include "cache.h"
 #include "config.h"
 #include "remote.h"
+#include "connect.h"
 #include "strbuf.h"
 #include "walker.h"
 #include "http.h"
@@ -13,6 +14,7 @@
 #include "credential.h"
 #include "sha1-array.h"
 #include "send-pack.h"
+#include "protocol.h"
 #include "quote.h"
 
 static struct remote *remote;
@@ -184,12 +186,13 @@ static int set_option(const char *name, const char *value)
 }
 
 struct discovery {
-	const char *service;
+	char *service;
 	char *buf_alloc;
 	char *buf;
 	size_t len;
 	struct ref *refs;
 	struct oid_array shallow;
+	enum protocol_version version;
 	unsigned proto_git : 1;
 };
 static struct discovery *last_discovery;
@@ -197,8 +200,31 @@ static struct discovery *last_discovery;
 static struct ref *parse_git_refs(struct discovery *heads, int for_push)
 {
 	struct ref *list = NULL;
-	get_remote_heads(-1, heads->buf, heads->len, &list,
-			 for_push ? REF_NORMAL : 0, NULL, &heads->shallow);
+	struct packet_reader reader;
+
+	packet_reader_init(&reader, -1, heads->buf, heads->len,
+			   PACKET_READ_CHOMP_NEWLINE |
+			   PACKET_READ_GENTLE_ON_EOF);
+
+	heads->version = discover_version(&reader);
+	switch (heads->version) {
+	case protocol_v2:
+		/*
+		 * Do nothing.  This isn't a list of refs but rather a
+		 * capability advertisement.  Client would have run
+		 * 'stateless-connect' so we'll dump this capability listing
+		 * and let them request the refs themselves.
+		 */
+		break;
+	case protocol_v1:
+	case protocol_v0:
+		get_remote_heads(&reader, &list, for_push ? REF_NORMAL : 0,
+				 NULL, &heads->shallow);
+		break;
+	case protocol_unknown_version:
+		BUG("unknown protocol version");
+	}
+
 	return list;
 }
 
@@ -259,6 +285,7 @@ static void free_discovery(struct discovery *d)
 		free(d->shallow.oid);
 		free(d->buf_alloc);
 		free_refs(d->refs);
+		free(d->service);
 		free(d);
 	}
 }
@@ -290,6 +317,19 @@ static int show_http_message(struct strbuf *type, struct strbuf *charset,
 	return 0;
 }
 
+static int get_protocol_http_header(enum protocol_version version,
+				    struct strbuf *header)
+{
+	if (version > 0) {
+		strbuf_addf(header, GIT_PROTOCOL_HEADER ": version=%d",
+			    version);
+
+		return 1;
+	}
+
+	return 0;
+}
+
 static struct discovery *discover_refs(const char *service, int for_push)
 {
 	struct strbuf exp = STRBUF_INIT;
@@ -298,9 +338,12 @@ static struct discovery *discover_refs(const char *service, int for_push)
 	struct strbuf buffer = STRBUF_INIT;
 	struct strbuf refs_url = STRBUF_INIT;
 	struct strbuf effective_url = STRBUF_INIT;
+	struct strbuf protocol_header = STRBUF_INIT;
+	struct string_list extra_headers = STRING_LIST_INIT_DUP;
 	struct discovery *last = last_discovery;
 	int http_ret, maybe_smart = 0;
 	struct http_get_options http_options;
+	enum protocol_version version = get_protocol_version_config();
 
 	if (last && !strcmp(service, last->service))
 		return last;
@@ -317,11 +360,24 @@ static struct discovery *discover_refs(const char *service, int for_push)
 		strbuf_addf(&refs_url, "service=%s", service);
 	}
 
+	/*
+	 * NEEDSWORK: If we are trying to use protocol v2 and we are planning
+	 * to perform a push, then fallback to v0 since the client doesn't know
+	 * how to push yet using v2.
+	 */
+	if (version == protocol_v2 && !strcmp("git-receive-pack", service))
+		version = protocol_v0;
+
+	/* Add the extra Git-Protocol header */
+	if (get_protocol_http_header(version, &protocol_header))
+		string_list_append(&extra_headers, protocol_header.buf);
+
 	memset(&http_options, 0, sizeof(http_options));
 	http_options.content_type = &type;
 	http_options.charset = &charset;
 	http_options.effective_url = &effective_url;
 	http_options.base_url = &url;
+	http_options.extra_headers = &extra_headers;
 	http_options.initial_request = 1;
 	http_options.no_cache = 1;
 	http_options.keep_error = 1;
@@ -345,7 +401,7 @@ static struct discovery *discover_refs(const char *service, int for_push)
 		warning(_("redirecting to %s"), url.buf);
 
 	last= xcalloc(1, sizeof(*last_discovery));
-	last->service = service;
+	last->service = xstrdup(service);
 	last->buf_alloc = strbuf_detach(&buffer, &last->len);
 	last->buf = last->buf_alloc;
 
@@ -377,6 +433,9 @@ static struct discovery *discover_refs(const char *service, int for_push)
 			;
 
 		last->proto_git = 1;
+	} else if (maybe_smart &&
+		   last->len > 5 && starts_with(last->buf + 4, "version 2")) {
+		last->proto_git = 1;
 	}
 
 	if (last->proto_git)
@@ -390,6 +449,8 @@ static struct discovery *discover_refs(const char *service, int for_push)
 	strbuf_release(&charset);
 	strbuf_release(&effective_url);
 	strbuf_release(&buffer);
+	strbuf_release(&protocol_header);
+	string_list_clear(&extra_headers, 0);
 	last_discovery = last;
 	return last;
 }
@@ -426,6 +487,7 @@ struct rpc_state {
 	char *service_url;
 	char *hdr_content_type;
 	char *hdr_accept;
+	char *protocol_header;
 	char *buf;
 	size_t alloc;
 	size_t len;
@@ -612,6 +674,10 @@ static int post_rpc(struct rpc_state *rpc)
 	headers = curl_slist_append(headers, needs_100_continue ?
 		"Expect: 100-continue" : "Expect:");
 
+	/* Add the extra Git-Protocol header */
+	if (rpc->protocol_header)
+		headers = curl_slist_append(headers, rpc->protocol_header);
+
 retry:
 	slot = get_active_slot();
 
@@ -752,6 +818,11 @@ static int rpc_service(struct rpc_state *rpc, struct discovery *heads)
 	strbuf_addf(&buf, "Accept: application/x-%s-result", svc);
 	rpc->hdr_accept = strbuf_detach(&buf, NULL);
 
+	if (get_protocol_http_header(heads->version, &buf))
+		rpc->protocol_header = strbuf_detach(&buf, NULL);
+	else
+		rpc->protocol_header = NULL;
+
 	while (!err) {
 		int n = packet_read(rpc->out, NULL, NULL, rpc->buf, rpc->alloc, 0);
 		if (!n)
@@ -779,6 +850,7 @@ static int rpc_service(struct rpc_state *rpc, struct discovery *heads)
 	free(rpc->service_url);
 	free(rpc->hdr_content_type);
 	free(rpc->hdr_accept);
+	free(rpc->protocol_header);
 	free(rpc->buf);
 	strbuf_release(&buf);
 	return err;
@@ -1056,6 +1128,202 @@ static void parse_push(struct strbuf *buf)
 	free(specs);
 }
 
+/*
+ * Used to represent the state of a connection to an HTTP server when
+ * communicating using git's wire-protocol version 2.
+ */
+struct proxy_state {
+	char *service_name;
+	char *service_url;
+	struct curl_slist *headers;
+	struct strbuf request_buffer;
+	int in;
+	int out;
+	struct packet_reader reader;
+	size_t pos;
+	int seen_flush;
+};
+
+static void proxy_state_init(struct proxy_state *p, const char *service_name,
+			     enum protocol_version version)
+{
+	struct strbuf buf = STRBUF_INIT;
+
+	memset(p, 0, sizeof(*p));
+	p->service_name = xstrdup(service_name);
+
+	p->in = 0;
+	p->out = 1;
+	strbuf_init(&p->request_buffer, 0);
+
+	strbuf_addf(&buf, "%s%s", url.buf, p->service_name);
+	p->service_url = strbuf_detach(&buf, NULL);
+
+	p->headers = http_copy_default_headers();
+
+	strbuf_addf(&buf, "Content-Type: application/x-%s-request", p->service_name);
+	p->headers = curl_slist_append(p->headers, buf.buf);
+	strbuf_reset(&buf);
+
+	strbuf_addf(&buf, "Accept: application/x-%s-result", p->service_name);
+	p->headers = curl_slist_append(p->headers, buf.buf);
+	strbuf_reset(&buf);
+
+	p->headers = curl_slist_append(p->headers, "Transfer-Encoding: chunked");
+
+	/* Add the Git-Protocol header */
+	if (get_protocol_http_header(version, &buf))
+		p->headers = curl_slist_append(p->headers, buf.buf);
+
+	packet_reader_init(&p->reader, p->in, NULL, 0,
+			   PACKET_READ_GENTLE_ON_EOF);
+
+	strbuf_release(&buf);
+}
+
+static void proxy_state_clear(struct proxy_state *p)
+{
+	free(p->service_name);
+	free(p->service_url);
+	curl_slist_free_all(p->headers);
+	strbuf_release(&p->request_buffer);
+}
+
+/*
+ * CURLOPT_READFUNCTION callback function.
+ * Attempts to copy over a single packet-line at a time into the
+ * curl provided buffer.
+ */
+static size_t proxy_in(char *buffer, size_t eltsize,
+		       size_t nmemb, void *userdata)
+{
+	size_t max;
+	struct proxy_state *p = userdata;
+	size_t avail = p->request_buffer.len - p->pos;
+
+
+	if (eltsize != 1)
+		BUG("curl read callback called with size = %"PRIuMAX" != 1",
+		    (uintmax_t)eltsize);
+	max = nmemb;
+
+	if (!avail) {
+		if (p->seen_flush) {
+			p->seen_flush = 0;
+			return 0;
+		}
+
+		strbuf_reset(&p->request_buffer);
+		switch (packet_reader_read(&p->reader)) {
+		case PACKET_READ_EOF:
+			die("unexpected EOF when reading from parent process");
+		case PACKET_READ_NORMAL:
+			packet_buf_write_len(&p->request_buffer, p->reader.line,
+					     p->reader.pktlen);
+			break;
+		case PACKET_READ_DELIM:
+			packet_buf_delim(&p->request_buffer);
+			break;
+		case PACKET_READ_FLUSH:
+			packet_buf_flush(&p->request_buffer);
+			p->seen_flush = 1;
+			break;
+		}
+		p->pos = 0;
+		avail = p->request_buffer.len;
+	}
+
+	if (max < avail)
+		avail = max;
+	memcpy(buffer, p->request_buffer.buf + p->pos, avail);
+	p->pos += avail;
+	return avail;
+}
+
+static size_t proxy_out(char *buffer, size_t eltsize,
+			size_t nmemb, void *userdata)
+{
+	size_t size;
+	struct proxy_state *p = userdata;
+
+	if (eltsize != 1)
+		BUG("curl read callback called with size = %"PRIuMAX" != 1",
+		    (uintmax_t)eltsize);
+	size = nmemb;
+
+	write_or_die(p->out, buffer, size);
+	return size;
+}
+
+/* Issues a request to the HTTP server configured in `p` */
+static int proxy_request(struct proxy_state *p)
+{
+	struct active_request_slot *slot;
+
+	slot = get_active_slot();
+
+	curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 0);
+	curl_easy_setopt(slot->curl, CURLOPT_POST, 1);
+	curl_easy_setopt(slot->curl, CURLOPT_URL, p->service_url);
+	curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, p->headers);
+
+	/* Setup function to read request from client */
+	curl_easy_setopt(slot->curl, CURLOPT_READFUNCTION, proxy_in);
+	curl_easy_setopt(slot->curl, CURLOPT_READDATA, p);
+
+	/* Setup function to write server response to client */
+	curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, proxy_out);
+	curl_easy_setopt(slot->curl, CURLOPT_WRITEDATA, p);
+
+	if (run_slot(slot, NULL) != HTTP_OK)
+		return -1;
+
+	return 0;
+}
+
+static int stateless_connect(const char *service_name)
+{
+	struct discovery *discover;
+	struct proxy_state p;
+
+	/*
+	 * Run the info/refs request and see if the server supports protocol
+	 * v2.  If and only if the server supports v2 can we successfully
+	 * establish a stateless connection, otherwise we need to tell the
+	 * client to fallback to using other transport helper functions to
+	 * complete their request.
+	 */
+	discover = discover_refs(service_name, 0);
+	if (discover->version != protocol_v2) {
+		printf("fallback\n");
+		fflush(stdout);
+		return -1;
+	} else {
+		/* Stateless Connection established */
+		printf("\n");
+		fflush(stdout);
+	}
+
+	proxy_state_init(&p, service_name, discover->version);
+
+	/*
+	 * Dump the capability listing that we got from the server earlier
+	 * during the info/refs request.
+	 */
+	write_or_die(p.out, discover->buf, discover->len);
+
+	/* Peek the next packet line.  Until we see EOF keep sending POSTs */
+	while (packet_reader_peek(&p.reader) != PACKET_READ_EOF) {
+		if (proxy_request(&p)) {
+			/* We would have an err here */
+			break;
+		}
+	}
+
+	proxy_state_clear(&p);
+	return 0;
+}
+
 int cmd_main(int argc, const char **argv)
 {
 	struct strbuf buf = STRBUF_INIT;
@@ -1124,12 +1392,16 @@ int cmd_main(int argc, const char **argv)
 			fflush(stdout);
 
 		} else if (!strcmp(buf.buf, "capabilities")) {
+			printf("stateless-connect\n");
 			printf("fetch\n");
 			printf("option\n");
 			printf("push\n");
 			printf("check-connectivity\n");
 			printf("\n");
 			fflush(stdout);
+		} else if (skip_prefix(buf.buf, "stateless-connect ", &arg)) {
+			if (!stateless_connect(arg))
+				break;
 		} else {
 			error("remote-curl: unknown command '%s' from git", buf.buf);
 			return 1;