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authorBrandon Williams <bmwill@google.com>2017-10-16 17:55:24 (GMT)
committerJunio C Hamano <gitster@pobox.com>2017-10-17 01:51:29 (GMT)
commit373d70efb2278b76739d8c6538d4a4e59cc81bf7 (patch)
tree10c0e049cdd268c854253ca60bcb0d8da82ba1e2 /protocol.c
parent5d2124b34a11967b56bfeb57556be5e4583172c8 (diff)
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protocol: introduce protocol extension mechanisms
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 <bmwill@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'protocol.c')
-rw-r--r--protocol.c79
1 files changed, 79 insertions, 0 deletions
diff --git a/protocol.c b/protocol.c
new file mode 100644
index 0000000..43012b7
--- /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 state-of-the-art.
+ */
+ if (git_protocol) {
+ struct string_list list = STRING_LIST_INIT_DUP;
+ const struct string_list_item *item;
+ string_list_split(&list, git_protocol, ':', -1);
+
+ for_each_string_list_item(item, &list) {
+ const char *value;
+ enum protocol_version v;
+
+ if (skip_prefix(item->string, "version=", &value)) {
+ v = parse_protocol_version(value);
+ if (v > version)
+ version = v;
+ }
+ }
+
+ string_list_clear(&list, 0);
+ }
+
+ return version;
+}
+
+enum protocol_version determine_protocol_version_client(const char *server_response)
+{
+ enum protocol_version version = protocol_v0;
+
+ if (skip_prefix(server_response, "version ", &server_response)) {
+ version = parse_protocol_version(server_response);
+
+ if (version == protocol_unknown_version)
+ die("server is speaking an unknown protocol");
+ if (version == protocol_v0)
+ die("protocol error: server explicitly said version 0");
+ }
+
+ return version;
+}