[PATCH v3 4/9] bundle-uri: create "key=value" line parsing

["Ævar Arnfjörð Bjarmason via GitGitGadget" <gitgitgadget@xxxxxxxxx>]

From: =?UTF-8?q?=C3=86var=20Arnfj=C3=B6r=C3=B0=20Bjarmason?=
 <avarab@xxxxxxxxx>

When advertising a bundle list over Git's protocol v2, we will use
packet lines. Each line will be of the form "key=value" representing a
bundle list. Connect the API necessary for Git's transport to the
key-value pair parsing created in the previous change.

We are not currently implementing this protocol v2 functionality, but
instead preparing to expose this parsing to be unit-testable.

Co-authored-by: Derrick Stolee <derrickstolee@xxxxxxxxxx>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx>
Signed-off-by: Derrick Stolee <derrickstolee@xxxxxxxxxx>
---
 bundle-uri.c | 27 ++++++++++++++++++++++++++-
 bundle-uri.h | 12 ++++++++++++
 2 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/bundle-uri.c b/bundle-uri.c
index 0bc59dd9c34..372e6fac5cf 100644
--- a/bundle-uri.c
+++ b/bundle-uri.c
@@ -71,7 +71,6 @@ int for_all_bundles_in_list(struct bundle_list *list,
  * Returns 0 if the key-value pair is understood. Returns -1 if the key
  * is not understood or the value is malformed.
  */
-MAYBE_UNUSED
 static int bundle_list_update(const char *key, const char *value,
 			      struct bundle_list *list)
 {
@@ -306,3 +305,29 @@ cleanup:
 	free(filename);
 	return result;
 }
+
+/**
+ * General API for {transport,connect}.c etc.
+ */
+int bundle_uri_parse_line(struct bundle_list *list, const char *line)
+{
+	int result;
+	const char *equals;
+	struct strbuf key = STRBUF_INIT;
+
+	if (!strlen(line))
+		return error(_("bundle-uri: got an empty line"));
+
+	equals = strchr(line, '=');
+
+	if (!equals)
+		return error(_("bundle-uri: line is not of the form 'key=value'"));
+	if (line == equals || !*(equals + 1))
+		return error(_("bundle-uri: line has empty key or value"));
+
+	strbuf_add(&key, line, equals - line);
+	result = bundle_list_update(key.buf, equals + 1, list);
+	strbuf_release(&key);
+
+	return result;
+}
diff --git a/bundle-uri.h b/bundle-uri.h
index ff7e3fd3fb2..90583461929 100644
--- a/bundle-uri.h
+++ b/bundle-uri.h
@@ -67,4 +67,16 @@ int for_all_bundles_in_list(struct bundle_list *list,
  */
 int fetch_bundle_uri(struct repository *r, const char *uri);
 
+/**
+ * General API for {transport,connect}.c etc.
+ */
+
+/**
+ * Parse a "key=value" packet line from the bundle-uri verb.
+ *
+ * Returns 0 on success and non-zero on error.
+ */
+int bundle_uri_parse_line(struct bundle_list *list,
+			  const char *line);
+
 #endif
-- 
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