[PATCH 10/13] transport-helper: implement marks location as capability

[Sverre Rabbelier <srabbelier@gmail.com>]

While this requires the helper to flush stdout after listing 'gitdir'
as capability, and read a command (the 'gitdir' response from the
remote helper infrastructure) right after that, this is more elegant
and does not require an ad-hoc exchange of values.

CC: Daniel Barkalow <barkalow@iabervon.org>
---

  Daniel made some fuss about the ad-hoc exchange when I first sent
  the 'export command' series for review, and it's been nagging me.

  As you can see in the remote-testgit implementation, it's a bit
  icky on the helper side (you have to flush sdout and read another
  command in the middle of responding to 'capabilities'), but I think
  it's better than the alternative.

 git-remote-testgit.py |   29 ++++++++++++++++-------------
 transport-helper.c    |   47 ++++++++++++++++++-----------------------------
 2 files changed, 34 insertions(+), 42 deletions(-)

diff --git a/git-remote-testgit.py b/git-remote-testgit.py
index 50341ce..e2b213d 100644
--- a/git-remote-testgit.py
+++ b/git-remote-testgit.py
@@ -71,8 +71,24 @@ def do_capabilities(repo, args):
     print "import"
     print "export"
     print "gitdir"
+
+    sys.stdout.flush()
+    if not read_one_line(repo):
+        die("Expected gitdir, got empty line")
+
     print "refspec refs/heads/*:%s*" % repo.prefix
 
+    dirname = repo.get_base_path(repo.gitdir)
+
+    if not os.path.exists(dirname):
+        os.makedirs(dirname)
+
+    path = os.path.join(dirname, 'testgit.marks')
+
+    print "*export-marks %s" % path
+    if os.path.exists(path):
+        print "*import-marks %s" % path
+
     print # end capabilities
 
 
@@ -142,19 +158,6 @@ def do_export(repo, args):
     if not repo.gitdir:
         die("Need gitdir to export")
 
-    dirname = repo.get_base_path(repo.gitdir)
-
-    if not os.path.exists(dirname):
-        os.makedirs(dirname)
-
-    path = os.path.join(dirname, 'testgit.marks')
-    print path
-    if os.path.exists(path):
-        print path
-    else:
-        print ""
-    sys.stdout.flush()
-
     update_local_repo(repo)
     repo.importer.do_import(repo.gitdir)
     repo.non_local.push(repo.gitdir)
diff --git a/transport-helper.c b/transport-helper.c
index 82bdad3..0edc1d5 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -23,6 +23,8 @@ struct helper_data
 		push : 1,
 		connect : 1,
 		no_disconnect_req : 1;
+	char *export_marks;
+	char *import_marks;
 	/* These go from remote name (as in "list") to private name */
 	struct refspec *refspecs;
 	int refspec_nr;
@@ -179,6 +181,16 @@ static struct child_process *get_helper(struct transport *transport)
 			strbuf_addf(&gitdir, "gitdir %s\n", get_git_dir());
 			sendline(data, &gitdir);
 			strbuf_release(&gitdir);
+		} else if (!prefixcmp(capname, "export-marks ")) {
+			struct strbuf arg = STRBUF_INIT;
+			strbuf_addstr(&arg, "--export-marks=");
+			strbuf_addstr(&arg, capname + strlen("export-marks "));
+			data->export_marks = strbuf_detach(&arg, NULL);
+		} else if (!prefixcmp(capname, "import-marks")) {
+			struct strbuf arg = STRBUF_INIT;
+			strbuf_addstr(&arg, "--import-marks=");
+			strbuf_addstr(&arg, capname + strlen("import-marks "));
+			data->import_marks = strbuf_detach(&arg, NULL);
 		} else if (mandatory) {
 			die("Unknown mandatory capability %s. This remote "
 			    "helper probably needs newer version of Git.\n",
@@ -364,10 +376,9 @@ static int get_importer(struct transport *transport, struct child_process *fasti
 
 static int get_exporter(struct transport *transport,
 			struct child_process *fastexport,
-			const char *export_marks,
-			const char *import_marks,
 			struct string_list *revlist_args)
 {
+	struct helper_data *data = transport->data;
 	struct child_process *helper = get_helper(transport);
 	int argc = 0, i;
 	memset(fastexport, 0, sizeof(*fastexport));
@@ -378,10 +389,10 @@ static int get_exporter(struct transport *transport,
 	fastexport->argv = xcalloc(5 + revlist_args->nr, sizeof(*fastexport->argv));
 	fastexport->argv[argc++] = "fast-export";
 	fastexport->argv[argc++] = "--use-done-feature";
-	if (export_marks)
-		fastexport->argv[argc++] = export_marks;
-	if (import_marks)
-		fastexport->argv[argc++] = import_marks;
+	if (data->export_marks)
+		fastexport->argv[argc++] = data->export_marks;
+	if (data->import_marks)
+		fastexport->argv[argc++] = data->import_marks;
 
 	for (i = 0; i < revlist_args->nr; i++)
 		fastexport->argv[argc++] = revlist_args->items[i].string;
@@ -708,7 +719,6 @@ static int push_refs_with_export(struct transport *transport,
 	struct ref *ref;
 	struct child_process *helper, exporter;
 	struct helper_data *data = transport->data;
-	char *export_marks = NULL, *import_marks = NULL;
 	struct string_list revlist_args = { NULL, 0, 0 };
 	struct strbuf buf = STRBUF_INIT;
 
@@ -716,26 +726,6 @@ static int push_refs_with_export(struct transport *transport,
 
 	write_constant(helper->in, "export\n");
 
-	recvline(data, &buf);
-	if (debug)
-		fprintf(stderr, "Debug: Got export_marks '%s'\n", buf.buf);
-	if (buf.len) {
-		struct strbuf arg = STRBUF_INIT;
-		strbuf_addstr(&arg, "--export-marks=");
-		strbuf_addbuf(&arg, &buf);
-		export_marks = strbuf_detach(&arg, NULL);
-	}
-
-	recvline(data, &buf);
-	if (debug)
-		fprintf(stderr, "Debug: Got import_marks '%s'\n", buf.buf);
-	if (buf.len) {
-		struct strbuf arg = STRBUF_INIT;
-		strbuf_addstr(&arg, "--import-marks=");
-		strbuf_addbuf(&arg, &buf);
-		import_marks = strbuf_detach(&arg, NULL);
-	}
-
 	strbuf_reset(&buf);
 
 	for (ref = remote_refs; ref; ref = ref->next) {
@@ -754,8 +744,7 @@ static int push_refs_with_export(struct transport *transport,
 
 	}
 
-	if (get_exporter(transport, &exporter,
-			 export_marks, import_marks, &revlist_args))
+	if (get_exporter(transport, &exporter, &revlist_args))
 		die("Couldn't run fast-export");
 
 	if(finish_command(&exporter))
-- 
1.7.2.1.240.g6a95c3