Merge pull request #2376 from libgit2/cmn/remote-symref

Add support for the symref extension

5 files changed, 120 insertions, 11 deletions

diff --git a/src/transports/local.c b/src/transports/local.c
index 2c17e6271..8d3619388 100644
--- a/src/transports/local.c
+++ b/src/transports/local.c
@@ -43,14 +43,19 @@ typedef struct {
 static int add_ref(transport_local *t, const char *name)
 {
 	const char peeled[] = "^{}";
-	git_oid head_oid;
+	git_reference *ref, *resolved;
 	git_remote_head *head;
+	git_oid obj_id;
 	git_object *obj = NULL, *target = NULL;
 	git_buf buf = GIT_BUF_INIT;
 	int error;
 
-	error = git_reference_name_to_id(&head_oid, t->repo, name);
+	if ((error = git_reference_lookup(&ref, t->repo, name)) < 0)
+		return error;
+
+	error = git_reference_resolve(&resolved, ref);
 	if (error < 0) {
+		git_reference_free(ref);
 		if (!strcmp(name, GIT_HEAD_FILE) && error == GIT_ENOTFOUND) {
 			/* This is actually okay.  Empty repos often have a HEAD that
 			 * points to a nonexistent "refs/heads/master". */
@@ -60,13 +65,22 @@ static int add_ref(transport_local *t, const char *name)
 		return error;
 	}
 
+	git_oid_cpy(&obj_id, git_reference_target(resolved));
+	git_reference_free(resolved);
+
 	head = git__calloc(1, sizeof(git_remote_head));
 	GITERR_CHECK_ALLOC(head);
 
 	head->name = git__strdup(name);
 	GITERR_CHECK_ALLOC(head->name);
 
-	git_oid_cpy(&head->oid, &head_oid);
+	git_oid_cpy(&head->oid, &obj_id);
+
+	if (git_reference_type(ref) == GIT_REF_SYMBOLIC) {
+		head->symref_target = git__strdup(git_reference_symbolic_target(ref));
+		GITERR_CHECK_ALLOC(head->symref_target);
+	}
+	git_reference_free(ref);
 
 	if ((error = git_vector_insert(&t->refs, head)) < 0) {
 		git__free(head->name);
@@ -176,7 +190,7 @@ static int path_from_url_or_path(git_buf *local_path_out, const char *url_or_pat
 
 /*
  * Try to open the url as a git directory. The direction doesn't
- * matter in this case because we're calulating the heads ourselves.
+ * matter in this case because we're calculating the heads ourselves.
  */
 static int local_connect(
 	git_transport *transport,
diff --git a/src/transports/smart.c b/src/transports/smart.c
index 7fb41f788..c9845bff9 100644
--- a/src/transports/smart.c
+++ b/src/transports/smart.c
@@ -7,6 +7,7 @@
 #include "git2.h"
 #include "smart.h"
 #include "refs.h"
+#include "refspec.h"
 
 static int git_smart__recv_cb(gitno_buffer *buf)
 {
@@ -63,7 +64,7 @@ static int git_smart__set_callbacks(
 	return 0;
 }
 
-int git_smart__update_heads(transport_smart *t)
+int git_smart__update_heads(transport_smart *t, git_vector *symrefs)
 {
 	size_t i;
 	git_pkt *pkt;
@@ -74,6 +75,25 @@ int git_smart__update_heads(transport_smart *t)
 		if (pkt->type != GIT_PKT_REF)
 			continue;
 
+		if (symrefs) {
+			git_refspec *spec;
+			git_buf buf = GIT_BUF_INIT;
+			size_t j;
+			int error;
+
+			git_vector_foreach(symrefs, j, spec) {
+				git_buf_clear(&buf);
+				if (git_refspec_src_matches(spec, ref->head.name) &&
+				    !(error = git_refspec_transform(&buf, spec, ref->head.name)))
+					ref->head.symref_target = git_buf_detach(&buf);
+			}
+
+			git_buf_free(&buf);
+
+			if (error < 0)
+				return error;
+		}
+
 		if (git_vector_insert(&t->heads, &ref->head) < 0)
 			return -1;
 	}
@@ -81,6 +101,19 @@ int git_smart__update_heads(transport_smart *t)
 	return 0;
 }
 
+static void free_symrefs(git_vector *symrefs)
+{
+	git_refspec *spec;
+	size_t i;
+
+	git_vector_foreach(symrefs, i, spec) {
+		git_refspec__free(spec);
+		git__free(spec);
+	}
+
+	git_vector_free(symrefs);
+}
+
 static int git_smart__connect(
 	git_transport *transport,
 	const char *url,
@@ -94,6 +127,7 @@ static int git_smart__connect(
 	int error;
 	git_pkt *pkt;
 	git_pkt_ref *first;
+	git_vector symrefs;
 	git_smart_service_t service;
 
 	if (git_smart__reset_stream(t, true) < 0)
@@ -147,8 +181,11 @@ static int git_smart__connect(
 
 	first = (git_pkt_ref *)git_vector_get(&t->refs, 0);
 
+	if ((error = git_vector_init(&symrefs, 1, NULL)) < 0)
+		return error;
+
 	/* Detect capabilities */
-	if (git_smart__detect_caps(first, &t->caps) < 0)
+	if (git_smart__detect_caps(first, &t->caps, &symrefs) < 0)
 		return -1;
 
 	/* If the only ref in the list is capabilities^{} with OID_ZERO, remove it */
@@ -159,7 +196,9 @@ static int git_smart__connect(
 	}
 
 	/* Keep a list of heads for _ls */
-	git_smart__update_heads(t);
+	git_smart__update_heads(t, &symrefs);
+
+	free_symrefs(&symrefs);
 
 	if (t->rpc && git_smart__reset_stream(t, false) < 0)
 		return -1;
diff --git a/src/transports/smart.h b/src/transports/smart.h
index a2b6b2a71..f1fc29520 100644
--- a/src/transports/smart.h
+++ b/src/transports/smart.h
@@ -23,6 +23,7 @@
 #define GIT_CAP_DELETE_REFS "delete-refs"
 #define GIT_CAP_REPORT_STATUS "report-status"
 #define GIT_CAP_THIN_PACK "thin-pack"
+#define GIT_CAP_SYMREF "symref"
 
 enum git_pkt_type {
 	GIT_PKT_CMD,
@@ -154,7 +155,7 @@ typedef struct {
 
 /* smart_protocol.c */
 int git_smart__store_refs(transport_smart *t, int flushes);
-int git_smart__detect_caps(git_pkt_ref *pkt, transport_smart_caps *caps);
+int git_smart__detect_caps(git_pkt_ref *pkt, transport_smart_caps *caps, git_vector *symrefs);
 int git_smart__push(git_transport *transport, git_push *push);
 
 int git_smart__negotiate_fetch(
@@ -174,7 +175,7 @@ int git_smart__download_pack(
 int git_smart__negotiation_step(git_transport *transport, void *data, size_t len);
 int git_smart__get_push_stream(transport_smart *t, git_smart_subtransport_stream **out);
 
-int git_smart__update_heads(transport_smart *t);
+int git_smart__update_heads(transport_smart *t, git_vector *symrefs);
 
 /* smart_pkt.c */
 int git_pkt_parse_line(git_pkt **head, const char *line, const char **out, size_t len);
diff --git a/src/transports/smart_pkt.c b/src/transports/smart_pkt.c
index e9376ae6f..b5f9d6dbe 100644
--- a/src/transports/smart_pkt.c
+++ b/src/transports/smart_pkt.c
@@ -433,6 +433,7 @@ void git_pkt_free(git_pkt *pkt)
 	if (pkt->type == GIT_PKT_REF) {
 		git_pkt_ref *p = (git_pkt_ref *) pkt;
 		git__free(p->head.name);
+		git__free(p->head.symref_target);
 	}
 
 	if (pkt->type == GIT_PKT_OK) {
diff --git a/src/transports/smart_protocol.c b/src/transports/smart_protocol.c
index 5dd6bab24..bab0cf113 100644
--- a/src/transports/smart_protocol.c
+++ b/src/transports/smart_protocol.c
@@ -78,7 +78,52 @@ int git_smart__store_refs(transport_smart *t, int flushes)
 	return flush;
 }
 
-int git_smart__detect_caps(git_pkt_ref *pkt, transport_smart_caps *caps)
+static int append_symref(const char **out, git_vector *symrefs, const char *ptr)
+{
+	int error;
+	const char *end;
+	git_buf buf = GIT_BUF_INIT;
+	git_refspec *mapping;
+
+	ptr += strlen(GIT_CAP_SYMREF);
+	if (*ptr != '=')
+		goto on_invalid;
+
+	ptr++;
+	if (!(end = strchr(ptr, ' ')) &&
+	    !(end = strchr(ptr, '\0')))
+		goto on_invalid;
+
+	if ((error = git_buf_put(&buf, ptr, end - ptr)) < 0)
+		return error;
+
+	/* symref mapping has refspec format */
+	mapping = git__malloc(sizeof(git_refspec));
+	GITERR_CHECK_ALLOC(mapping);
+
+	error = git_refspec__parse(mapping, git_buf_cstr(&buf), true);
+	git_buf_free(&buf);
+
+	/* if the error isn't OOM, then it's a parse error; let's use a nicer message */
+	if (error < 0) {
+		if (giterr_last()->klass != GITERR_NOMEMORY)
+			goto on_invalid;
+
+		return error;
+	}
+
+	if ((error = git_vector_insert(symrefs, mapping)) < 0)
+		return error;
+
+	*out = end;
+	return 0;
+
+on_invalid:
+	giterr_set(GITERR_NET, "remote sent invalid symref");
+	return -1;
+}
+
+int git_smart__detect_caps(git_pkt_ref *pkt, transport_smart_caps *caps, git_vector *symrefs)
 {
 	const char *ptr;
 
@@ -141,6 +186,15 @@ int git_smart__detect_caps(git_pkt_ref *pkt, transport_smart_caps *caps)
 			continue;
 		}
 
+		if (!git__prefixcmp(ptr, GIT_CAP_SYMREF)) {
+			int error;
+
+			if ((error = append_symref(&ptr, symrefs, ptr)) < 0)
+				return error;
+
+			continue;
+		}
+
 		/* We don't know this capability, so skip it */
 		ptr = strchr(ptr, ' ');
 	}
@@ -969,7 +1023,7 @@ int git_smart__push(git_transport *transport, git_push *push)
 		if (error < 0)
 			goto done;
 
-		error = git_smart__update_heads(t);
+		error = git_smart__update_heads(t, NULL);
 	}
 
 done: