upload-pack: introduce fetch server command

Introduce the 'fetch' server command.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 266 insertions, 0 deletions

diff --git a/upload-pack.c b/upload-pack.c
index 1e8a9e1..198e9f0 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -18,6 +18,7 @@
 #include "prio-queue.h"
 #include "protocol.h"
 #include "upload-pack.h"
+#include "serve.h"
 
 /* Remember to update object flag allocation in object.h */
 #define THEY_HAVE	(1u << 11)
@@ -1065,3 +1066,268 @@ void upload_pack(struct upload_pack_options *options)
 		create_pack_file();
 	}
 }
+
+struct upload_pack_data {
+	struct object_array wants;
+	struct oid_array haves;
+
+	unsigned stateless_rpc : 1;
+
+	unsigned use_thin_pack : 1;
+	unsigned use_ofs_delta : 1;
+	unsigned no_progress : 1;
+	unsigned use_include_tag : 1;
+	unsigned done : 1;
+};
+
+static void upload_pack_data_init(struct upload_pack_data *data)
+{
+	struct object_array wants = OBJECT_ARRAY_INIT;
+	struct oid_array haves = OID_ARRAY_INIT;
+
+	memset(data, 0, sizeof(*data));
+	data->wants = wants;
+	data->haves = haves;
+}
+
+static void upload_pack_data_clear(struct upload_pack_data *data)
+{
+	object_array_clear(&data->wants);
+	oid_array_clear(&data->haves);
+}
+
+static int parse_want(const char *line)
+{
+	const char *arg;
+	if (skip_prefix(line, "want ", &arg)) {
+		struct object_id oid;
+		struct object *o;
+
+		if (get_oid_hex(arg, &oid))
+			die("git upload-pack: protocol error, "
+			    "expected to get oid, not '%s'", line);
+
+		o = parse_object(&oid);
+		if (!o) {
+			packet_write_fmt(1,
+					 "ERR upload-pack: not our ref %s",
+					 oid_to_hex(&oid));
+			die("git upload-pack: not our ref %s",
+			    oid_to_hex(&oid));
+		}
+
+		if (!(o->flags & WANTED)) {
+			o->flags |= WANTED;
+			add_object_array(o, NULL, &want_obj);
+		}
+
+		return 1;
+	}
+
+	return 0;
+}
+
+static int parse_have(const char *line, struct oid_array *haves)
+{
+	const char *arg;
+	if (skip_prefix(line, "have ", &arg)) {
+		struct object_id oid;
+
+		if (get_oid_hex(arg, &oid))
+			die("git upload-pack: expected SHA1 object, got '%s'", arg);
+		oid_array_append(haves, &oid);
+		return 1;
+	}
+
+	return 0;
+}
+
+static void process_args(struct packet_reader *request,
+			 struct upload_pack_data *data)
+{
+	while (packet_reader_read(request) != PACKET_READ_FLUSH) {
+		const char *arg = request->line;
+
+		/* process want */
+		if (parse_want(arg))
+			continue;
+		/* process have line */
+		if (parse_have(arg, &data->haves))
+			continue;
+
+		/* process args like thin-pack */
+		if (!strcmp(arg, "thin-pack")) {
+			use_thin_pack = 1;
+			continue;
+		}
+		if (!strcmp(arg, "ofs-delta")) {
+			use_ofs_delta = 1;
+			continue;
+		}
+		if (!strcmp(arg, "no-progress")) {
+			no_progress = 1;
+			continue;
+		}
+		if (!strcmp(arg, "include-tag")) {
+			use_include_tag = 1;
+			continue;
+		}
+		if (!strcmp(arg, "done")) {
+			data->done = 1;
+			continue;
+		}
+
+		/* ignore unknown lines maybe? */
+		die("unexpect line: '%s'", arg);
+	}
+}
+
+static int process_haves(struct oid_array *haves, struct oid_array *common)
+{
+	int i;
+
+	/* Process haves */
+	for (i = 0; i < haves->nr; i++) {
+		const struct object_id *oid = &haves->oid[i];
+		struct object *o;
+		int we_knew_they_have = 0;
+
+		if (!has_object_file(oid))
+			continue;
+
+		oid_array_append(common, oid);
+
+		o = parse_object(oid);
+		if (!o)
+			die("oops (%s)", oid_to_hex(oid));
+		if (o->type == OBJ_COMMIT) {
+			struct commit_list *parents;
+			struct commit *commit = (struct commit *)o;
+			if (o->flags & THEY_HAVE)
+				we_knew_they_have = 1;
+			else
+				o->flags |= THEY_HAVE;
+			if (!oldest_have || (commit->date < oldest_have))
+				oldest_have = commit->date;
+			for (parents = commit->parents;
+			     parents;
+			     parents = parents->next)
+				parents->item->object.flags |= THEY_HAVE;
+		}
+		if (!we_knew_they_have)
+			add_object_array(o, NULL, &have_obj);
+	}
+
+	return 0;
+}
+
+static int send_acks(struct oid_array *acks, struct strbuf *response)
+{
+	int i;
+
+	packet_buf_write(response, "acknowledgments\n");
+
+	/* Send Acks */
+	if (!acks->nr)
+		packet_buf_write(response, "NAK\n");
+
+	for (i = 0; i < acks->nr; i++) {
+		packet_buf_write(response, "ACK %s\n",
+				 oid_to_hex(&acks->oid[i]));
+	}
+
+	if (ok_to_give_up()) {
+		/* Send Ready */
+		packet_buf_write(response, "ready\n");
+		return 1;
+	}
+
+	return 0;
+}
+
+static int process_haves_and_send_acks(struct upload_pack_data *data)
+{
+	struct oid_array common = OID_ARRAY_INIT;
+	struct strbuf response = STRBUF_INIT;
+	int ret = 0;
+
+	process_haves(&data->haves, &common);
+	if (data->done) {
+		ret = 1;
+	} else if (send_acks(&common, &response)) {
+		packet_buf_delim(&response);
+		ret = 1;
+	} else {
+		/* Add Flush */
+		packet_buf_flush(&response);
+		ret = 0;
+	}
+
+	/* Send response */
+	write_or_die(1, response.buf, response.len);
+	strbuf_release(&response);
+
+	oid_array_clear(&data->haves);
+	oid_array_clear(&common);
+	return ret;
+}
+
+enum fetch_state {
+	FETCH_PROCESS_ARGS = 0,
+	FETCH_SEND_ACKS,
+	FETCH_SEND_PACK,
+	FETCH_DONE,
+};
+
+int upload_pack_v2(struct repository *r, struct argv_array *keys,
+		   struct packet_reader *request)
+{
+	enum fetch_state state = FETCH_PROCESS_ARGS;
+	struct upload_pack_data data;
+
+	upload_pack_data_init(&data);
+	use_sideband = LARGE_PACKET_MAX;
+
+	while (state != FETCH_DONE) {
+		switch (state) {
+		case FETCH_PROCESS_ARGS:
+			process_args(request, &data);
+
+			if (!want_obj.nr) {
+				/*
+				 * Request didn't contain any 'want' lines,
+				 * guess they didn't want anything.
+				 */
+				state = FETCH_DONE;
+			} else if (data.haves.nr) {
+				/*
+				 * Request had 'have' lines, so lets ACK them.
+				 */
+				state = FETCH_SEND_ACKS;
+			} else {
+				/*
+				 * Request had 'want's but no 'have's so we can
+				 * immedietly go to construct and send a pack.
+				 */
+				state = FETCH_SEND_PACK;
+			}
+			break;
+		case FETCH_SEND_ACKS:
+			if (process_haves_and_send_acks(&data))
+				state = FETCH_SEND_PACK;
+			else
+				state = FETCH_DONE;
+			break;
+		case FETCH_SEND_PACK:
+			packet_write_fmt(1, "packfile\n");
+			create_pack_file();
+			state = FETCH_DONE;
+			break;
+		case FETCH_DONE:
+			continue;
+		}
+	}
+
+	upload_pack_data_clear(&data);
+	return 0;
+}