[RFCv2 07/16] transport: add infrastructure to support a protocol version number

[Stefan Beller <sbeller@google.com>]

Signed-off-by: Stefan Beller <sbeller@google.com>
---

Notes:
    This patch has been split up into 2 parts.
    This first part only introduces the infrastructure
    without exposing it to the user at all (no command line
    option nor a repository configuration option).
    
    The exposure to the user will be added in a later second
    patch. This allows us some time in between to build all
    the features we want without the requirement to be
    functional.

 remote.h           |  2 ++
 transport-helper.c |  1 +
 transport.c        | 15 +++++++++++++++
 transport.h        |  5 +++++
 4 files changed, 23 insertions(+)

diff --git a/remote.h b/remote.h
index 16cacfe..3767bed 100644
--- a/remote.h
+++ b/remote.h
@@ -50,6 +50,8 @@ struct remote {
 	const char *receivepack;
 	const char *uploadpack;
 
+	int transport_version;
+
 	/*
 	 * for curl remotes only
 	 */
diff --git a/transport-helper.c b/transport-helper.c
index 5d99a6b..ab3cd5b 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -247,6 +247,7 @@ static int disconnect_helper(struct transport *transport)
 }
 
 static const char *unsupported_options[] = {
+	TRANS_OPT_TRANSPORTVERSION,
 	TRANS_OPT_UPLOADPACK,
 	TRANS_OPT_RECEIVEPACK,
 	TRANS_OPT_THIN,
diff --git a/transport.c b/transport.c
index f080e93..651f0ac 100644
--- a/transport.c
+++ b/transport.c
@@ -479,6 +479,16 @@ static int set_git_option(struct git_transport_options *opts,
 	} else if (!strcmp(name, TRANS_OPT_PUSH_CERT)) {
 		opts->push_cert = !!value;
 		return 0;
+	} else if (!strcmp(name, TRANS_OPT_TRANSPORTVERSION)) {
+		if (!value)
+			opts->transport_version = DEFAULT_TRANSPORT_VERSION;
+		else {
+			char *end;
+			opts->transport_version = strtol(value, &end, 0);
+			if (*end)
+				die("transport: invalid transport version option '%s'", value);
+		}
+		return 0;
 	}
 	return 1;
 }
@@ -970,6 +980,8 @@ struct transport *transport_get(struct remote *remote, const char *url)
 		ret->connect = connect_git;
 		ret->disconnect = disconnect_git;
 		ret->smart_options = &(data->options);
+		ret->smart_options->transport_version =
+			DEFAULT_TRANSPORT_VERSION;
 
 		data->conn = NULL;
 		data->got_remote_heads = 0;
@@ -988,6 +1000,9 @@ struct transport *transport_get(struct remote *remote, const char *url)
 		ret->smart_options->receivepack = "git-receive-pack";
 		if (remote->receivepack)
 			ret->smart_options->receivepack = remote->receivepack;
+		if (remote->transport_version)
+			ret->smart_options->transport_version =
+				remote->transport_version;
 	}
 
 	return ret;
diff --git a/transport.h b/transport.h
index 18d2cf8..6095d7a 100644
--- a/transport.h
+++ b/transport.h
@@ -14,6 +14,7 @@ struct git_transport_options {
 	unsigned update_shallow : 1;
 	unsigned push_cert : 1;
 	int depth;
+	int transport_version;
 	const char *uploadpack;
 	const char *receivepack;
 	struct push_cas_option *cas;
@@ -162,6 +163,10 @@ struct transport *transport_get(struct remote *, const char *);
 /* Send push certificates */
 #define TRANS_OPT_PUSH_CERT "pushcert"
 
+/* Use a new version of the git protocol */
+#define TRANS_OPT_TRANSPORTVERSION "transportversion"
+#define DEFAULT_TRANSPORT_VERSION 1
+
 /**
  * Returns 0 if the option was used, non-zero otherwise. Prints a
  * message to stderr if the option is not used.
-- 
2.4.1.345.gab207b6.dirty