Create protocol.{c,h} and provide functions which future servers and
clients can use to determine which protocol to use or is being used.
Also introduce the 'GIT_PROTOCOL' environment variable which will be
used to communicate a colon separated list of keys with optional values
to a server. Unknown keys and values must be tolerated. This mechanism
is used to communicate which version of the wire protocol a client would
like to use with a server.
Signed-off-by: Brandon Williams
---
Documentation/config.txt | 17 +++
Documentation/git.txt| 6
Makefile | 1 +
cache.h | 8 +
protocol.c | 79
protocol.h | 33
6 files changed, 144 insertions(+)
create mode 100644 protocol.c
create mode 100644 protocol.h
diff --git a/Documentation/config.txt b/Documentation/config.txt
index dc4e3f58a..b78747abc 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -2517,6 +2517,23 @@ The protocol names currently used by git are:
`hg` to allow the `git-remote-hg` helper)
--
+protocol.version::
+ Experimental. If set, clients will attempt to communicate with a
+ server using the specified protocol version. If unset, no
+ attempt will be made by the client to communicate using a
+ particular protocol version, this results in protocol version 0
+ being used.
+ Supported versions:
++
+--
+
+* `0` - the original wire protocol.
+
+* `1` - the original wire protocol with the addition of a version string
+ in the initial response from the server.
+
+--
+
pull.ff::
By default, Git does not create an extra merge commit when merging
a commit that is a descendant of the current commit. Instead, the
diff --git a/Documentation/git.txt b/Documentation/git.txt
index 6e3a6767e..7518ea3af 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -697,6 +697,12 @@ of clones and fetches.
which feed potentially-untrusted URLS to git commands. See
linkgit:git-config[1] for more details.
+`GIT_PROTOCOL`::
+ For internal use only. Used in handshaking the wire protocol.
+ Contains a colon ':' separated list of keys with optional values
+ 'key[=value]'. Presence of unknown keys and values must be
+ ignored.
+
Discussion[[Discussion]]
diff --git a/Makefile b/Makefile
index ed4ca438b..9ce68cded 100644
--- a/Makefile
+++ b/Makefile
@@ -842,6 +842,7 @@ LIB_OBJS += pretty.o
LIB_OBJS += prio-queue.o
LIB_OBJS += progress.o
LIB_OBJS += prompt.o
+LIB_OBJS += protocol.o
LIB_OBJS += quote.o
LIB_OBJS += reachable.o
LIB_OBJS += read-cache.o
diff --git a/cache.h b/cache.h
index 49b083ee0..c74b73671 100644
--- a/cache.h
+++ b/cache.h
@@ -445,6 +445,14 @@ static inline enum object_type object_type(unsigned int
mode)
#define GIT_ICASE_PATHSPECS_ENVIRONMENT "GIT_ICASE_PATHSPECS"
#define GIT_QUARANTINE_ENVIRONMENT "GIT_QUARANTINE_PATH"
+/*
+ * Environment variable used in handshaking the wire protocol.
+ * Contains a colon ':' separated list of keys with optional values
+ * 'key[=value]'. Presence of unknown keys and values must be
+ * ignored.
+ */
+#define GIT_PROTOCOL_ENVIRONMENT "GIT_PROTOCOL"
+
/*
* This environment variable is expected to contain a boolean indicating
* whether we should or should not treat:
diff --git a/protocol.c b/protocol.c
new file mode 100644
index 0..43012b7eb
--- /dev/null
+++ b/protocol.c
@@ -0,0 +1,79 @@
+#include "cache.h"
+#include "config.h"
+#include "protocol.h"
+
+static enum protocol_version parse_protocol_version(const char *value)
+{
+ if (!strcmp(value, "0"))
+ return protocol_v0;
+ else if (!strcmp(value, "1"))
+ return protocol_v1;
+ else
+ return protocol_unknown_version;
+}
+
+enum protocol_version get_protocol_version_config(void)
+{
+ const char *value;
+ if (!git_config_get_string_const("protocol.version", &value)) {
+ enum protocol_version version = parse_protocol_version(value);
+
+ if (version == protocol_unknown_version)
+ die("unknown value for config 'protocol.version': %s",
+ value);
+
+ return version;
+ }
+
+ return protocol_v0;
+}
+
+enum protocol_version determine_protocol_version_server(void)
+{
+ const char *git_protocol = getenv(GIT_PROTOCOL_ENVIRONMENT);
+ enum protocol_version version = protocol_v0;
+
+ /*
+* Determine which protocol version the client has requested. Since
+* multiple 'version' keys can be sent by the client, indicating that
+* the client is okay to speak any of them, select the greatest version
+* that the client has requested. This is due to the assumption that
+* the most recent protocol version will be the most stat
