remote-helpers: Support custom transport options

Some transports, like the native pack transport implemented by
fetch-pack, support useful features like depth or include tags.
These should be exposed if the underlying helper knows how to
use them.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
CC: Daniel Barkalow <barkalow@iabervon.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 87 insertions, 1 deletions

diff --git a/transport-helper.c b/transport-helper.c
index 9de3408947..577abc638e 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -5,13 +5,15 @@
 #include "commit.h"
 #include "diff.h"
 #include "revision.h"
+#include "quote.h"
 
 struct helper_data
 {
 	const char *name;
 	struct child_process *helper;
 	FILE *out;
-	unsigned fetch : 1;
+	unsigned fetch : 1,
+		option : 1;
 };
 
 static struct child_process *get_helper(struct transport *transport)
@@ -48,6 +50,8 @@ static struct child_process *get_helper(struct transport *transport)
 			break;
 		if (!strcmp(buf.buf, "fetch"))
 			data->fetch = 1;
+		if (!strcmp(buf.buf, "option"))
+			data->option = 1;
 	}
 	return data->helper;
 }
@@ -65,9 +69,88 @@ static int disconnect_helper(struct transport *transport)
 		free(data->helper);
 		data->helper = NULL;
 	}
+	free(data);
 	return 0;
 }
 
+static const char *unsupported_options[] = {
+	TRANS_OPT_UPLOADPACK,
+	TRANS_OPT_RECEIVEPACK,
+	TRANS_OPT_THIN,
+	TRANS_OPT_KEEP
+	};
+static const char *boolean_options[] = {
+	TRANS_OPT_THIN,
+	TRANS_OPT_KEEP,
+	TRANS_OPT_FOLLOWTAGS
+	};
+
+static int set_helper_option(struct transport *transport,
+			  const char *name, const char *value)
+{
+	struct helper_data *data = transport->data;
+	struct child_process *helper = get_helper(transport);
+	struct strbuf buf = STRBUF_INIT;
+	int i, ret, is_bool = 0;
+
+	if (!data->option)
+		return 1;
+
+	for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
+		if (!strcmp(name, unsupported_options[i]))
+			return 1;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
+		if (!strcmp(name, boolean_options[i])) {
+			is_bool = 1;
+			break;
+		}
+	}
+
+	strbuf_addf(&buf, "option %s ", name);
+	if (is_bool)
+		strbuf_addstr(&buf, value ? "true" : "false");
+	else
+		quote_c_style(value, &buf, NULL, 0);
+	strbuf_addch(&buf, '\n');
+
+	if (write_in_full(helper->in, buf.buf, buf.len) != buf.len)
+		die_errno("cannot send option to %s", data->name);
+
+	strbuf_reset(&buf);
+	if (strbuf_getline(&buf, data->out, '\n') == EOF)
+		exit(128); /* child died, message supplied already */
+
+	if (!strcmp(buf.buf, "ok"))
+		ret = 0;
+	else if (!prefixcmp(buf.buf, "error")) {
+		ret = -1;
+	} else if (!strcmp(buf.buf, "unsupported"))
+		ret = 1;
+	else {
+		warning("%s unexpectedly said: '%s'", data->name, buf.buf);
+		ret = 1;
+	}
+	strbuf_release(&buf);
+	return ret;
+}
+
+static void standard_options(struct transport *t)
+{
+	char buf[16];
+	int n;
+	int v = t->verbose;
+	int no_progress = v < 0 || (!t->progress && !isatty(1));
+
+	set_helper_option(t, "progress", !no_progress ? "true" : "false");
+
+	n = snprintf(buf, sizeof(buf), "%d", v + 1);
+	if (n >= sizeof(buf))
+		die("impossibly large verbosity value");
+	set_helper_option(t, "verbosity", buf);
+}
+
 static int fetch_with_fetch(struct transport *transport,
 			    int nr_heads, const struct ref **to_fetch)
 {
@@ -75,6 +158,8 @@ static int fetch_with_fetch(struct transport *transport,
 	int i;
 	struct strbuf buf = STRBUF_INIT;
 
+	standard_options(transport);
+
 	for (i = 0; i < nr_heads; i++) {
 		const struct ref *posn = to_fetch[i];
 		if (posn->status & REF_STATUS_UPTODATE)
@@ -178,6 +263,7 @@ int transport_helper_init(struct transport *transport, const char *name)
 	data->name = name;
 
 	transport->data = data;
+	transport->set_option = set_helper_option;
 	transport->get_refs_list = get_refs_list;
 	transport->fetch = fetch;
 	transport->disconnect = disconnect_helper;