[v3,10/44] connect: add function to detect supported v1 hash functions

Commit Message

brian m. carlson June 19, 2020, 5:55 p.m. UTC

Add a function, server_supports_hash, to see if the remote server
supports a particular hash algorithm when speaking protocol v1.

Signed-off-by: brian m. carlson <[e-mail]>
---
 connect.c | 22 ++++++++++++++++++++++
 connect.h |  1 +
 2 files changed, 23 insertions(+)

Patch

diff --git a/connect.c b/connect.c
index 2cded78b0a..a52b038865 100644
--- a/connect.c
+++ b/connect.c
@@ -527,6 +527,28 @@  static const char *parse_feature_value(const char *feature_list, const char *fea
 	return NULL;
 }
 
+int server_supports_hash(const char *desired, int *feature_supported)
+{
+	int offset = 0;
+	int len;
+	const char *hash;
+
+	hash = next_server_feature_value("object-format", &len, &offset);
+	if (feature_supported)
+		*feature_supported = !!hash;
+	if (!hash) {
+		hash = hash_algos[GIT_HASH_SHA1].name;
+		len = strlen(hash);
+	}
+	while (hash) {
+		if (!xstrncmpz(desired, hash, len))
+			return 1;
+
+		hash = next_server_feature_value("object-format", &len, &offset);
+	}
+	return 0;
+}
+
 int parse_feature_request(const char *feature_list, const char *feature)
 {
 	return !!parse_feature_value(feature_list, feature, NULL, NULL);
diff --git a/connect.h b/connect.h
index 88702fdd17..c53976f7ec 100644
--- a/connect.h
+++ b/connect.h
@@ -18,6 +18,7 @@  int url_is_local_not_ssh(const char *url);
 struct packet_reader;
 enum protocol_version discover_version(struct packet_reader *reader);
 
+int server_supports_hash(const char *desired, int *feature_supported);
 int server_supports_v2(const char *c, int die_on_error);
 int server_feature_v2(const char *c, const char **v);
 int server_supports_feature(const char *c, const char *feature,