git/transport-helper.c

#include "cache.h"
#include "transport.h"

#include "run-command.h"
#include "commit.h"
#include "diff.h"
#include "revision.h"
#include "remote.h"

struct helper_data
{
	const char *name;
	struct child_process *helper;
	unsigned fetch : 1;
	unsigned import : 1;
	/* These go from remote name (as in "list") to private name */
	struct refspec *refspecs;
	int refspec_nr;
};

static struct child_process *get_helper(struct transport *transport)
{
	struct helper_data *data = transport->data;
	struct strbuf buf = STRBUF_INIT;
	struct child_process *helper;
	FILE *file;
	const char **refspecs = NULL;
	int refspec_nr = 0;
	int refspec_alloc = 0;

	if (data->helper)
		return data->helper;

	helper = xcalloc(1, sizeof(*helper));
	helper->in = -1;
	helper->out = -1;
	helper->err = 0;
	helper->argv = xcalloc(4, sizeof(*helper->argv));
	strbuf_addf(&buf, "remote-%s", data->name);
	helper->argv[0] = strbuf_detach(&buf, NULL);
	helper->argv[1] = transport->remote->name;
	helper->argv[2] = transport->url;
	helper->git_cmd = 1;
	if (start_command(helper))
		die("Unable to run helper: git %s", helper->argv[0]);
	data->helper = helper;

	write_str_in_full(helper->in, "capabilities\n");

	file = xfdopen(helper->out, "r");
	while (1) {
		if (strbuf_getline(&buf, file, '\n') == EOF)
			exit(128); /* child died, message supplied already */

		if (!*buf.buf)
			break;
		if (!strcmp(buf.buf, "fetch"))
			data->fetch = 1;
		if (!strcmp(buf.buf, "import"))
			data->import = 1;
		if (!data->refspecs && !prefixcmp(buf.buf, "refspec ")) {
			ALLOC_GROW(refspecs,
				   refspec_nr + 1,
				   refspec_alloc);
			refspecs[refspec_nr++] = strdup(buf.buf + strlen("refspec "));
		}
	}
	if (refspecs) {
		int i;
		data->refspec_nr = refspec_nr;
		data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
		for (i = 0; i < refspec_nr; i++) {
			free((char *)refspecs[i]);
		}
		free(refspecs);
	}
	strbuf_release(&buf);
	return data->helper;
}

static int disconnect_helper(struct transport *transport)
{
	struct helper_data *data = transport->data;
	if (data->helper) {
		write_str_in_full(data->helper->in, "\n");
		close(data->helper->in);
		finish_command(data->helper);
		free((char *)data->helper->argv[0]);
		free(data->helper->argv);
		free(data->helper);
		data->helper = NULL;
	}
	return 0;
}

static int release_helper(struct transport *transport)
{
	struct helper_data *data = transport->data;
	free_refspec(data->refspec_nr, data->refspecs);
	data->refspecs = NULL;
	disconnect_helper(transport);
	free(transport->data);
	return 0;
}

static int fetch_with_fetch(struct transport *transport,
			    int nr_heads, struct ref **to_fetch)
{
	struct child_process *helper = get_helper(transport);
	FILE *file = xfdopen(helper->out, "r");
	int i;
	struct strbuf buf = STRBUF_INIT;

	for (i = 0; i < nr_heads; i++) {
		const struct ref *posn = to_fetch[i];
		if (posn->status & REF_STATUS_UPTODATE)
			continue;

		strbuf_addf(&buf, "fetch %s %s\n",
			    sha1_to_hex(posn->old_sha1), posn->name);
		write_in_full(helper->in, buf.buf, buf.len);
		strbuf_reset(&buf);

		if (strbuf_getline(&buf, file, '\n') == EOF)
			exit(128); /* child died, message supplied already */
	}
	return 0;
}

static int get_importer(struct transport *transport, struct child_process *fastimport)
{
	struct child_process *helper = get_helper(transport);
	memset(fastimport, 0, sizeof(*fastimport));
	fastimport->in = helper->out;
	fastimport->argv = xcalloc(5, sizeof(*fastimport->argv));
	fastimport->argv[0] = "fast-import";
	fastimport->argv[1] = "--quiet";

	fastimport->git_cmd = 1;
	return start_command(fastimport);
}

static int fetch_with_import(struct transport *transport,
			     int nr_heads, struct ref **to_fetch)
{
	struct child_process fastimport;
	struct child_process *helper = get_helper(transport);
	struct helper_data *data = transport->data;
	int i;
	struct ref *posn;
	struct strbuf buf = STRBUF_INIT;

	if (get_importer(transport, &fastimport))
		die("Couldn't run fast-import");

	for (i = 0; i < nr_heads; i++) {
		posn = to_fetch[i];
		if (posn->status & REF_STATUS_UPTODATE)
			continue;

		strbuf_addf(&buf, "import %s\n", posn->name);
		write_in_full(helper->in, buf.buf, buf.len);
		strbuf_reset(&buf);
	}
	disconnect_helper(transport);
	finish_command(&fastimport);
	free(fastimport.argv);
	fastimport.argv = NULL;

	for (i = 0; i < nr_heads; i++) {
		char *private;
		posn = to_fetch[i];
		if (posn->status & REF_STATUS_UPTODATE)
			continue;
		if (data->refspecs)
			private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
		else
			private = strdup(posn->name);
		read_ref(private, posn->old_sha1);
		free(private);
	}
	strbuf_release(&buf);
	return 0;
}

static int fetch(struct transport *transport,
		 int nr_heads, struct ref **to_fetch)
{
	struct helper_data *data = transport->data;
	int i, count;

	count = 0;
	for (i = 0; i < nr_heads; i++)
		if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
			count++;

	if (!count)
		return 0;

	if (data->fetch)
		return fetch_with_fetch(transport, nr_heads, to_fetch);

	if (data->import)
		return fetch_with_import(transport, nr_heads, to_fetch);

	return -1;
}

static int has_attribute(const char *attrs, const char *attr) {
	int len;
	if (!attrs)
		return 0;

	len = strlen(attr);
	for (;;) {
		const char *space = strchrnul(attrs, ' ');
		if (len == space - attrs && !strncmp(attrs, attr, len))
			return 1;
		if (!*space)
			return 0;
		attrs = space + 1;
	}
}

static struct ref *get_refs_list(struct transport *transport, int for_push)
{
	struct child_process *helper;
	struct ref *ret = NULL;
	struct ref **tail = &ret;
	struct ref *posn;
	struct strbuf buf = STRBUF_INIT;
	FILE *file;

	helper = get_helper(transport);

	write_str_in_full(helper->in, "list\n");

	file = xfdopen(helper->out, "r");
	while (1) {
		char *eov, *eon;
		if (strbuf_getline(&buf, file, '\n') == EOF)
			exit(128); /* child died, message supplied already */

		if (!*buf.buf)
			break;

		eov = strchr(buf.buf, ' ');
		if (!eov)
			die("Malformed response in ref list: %s", buf.buf);
		eon = strchr(eov + 1, ' ');
		*eov = '\0';
		if (eon)
			*eon = '\0';
		*tail = alloc_ref(eov + 1);
		if (buf.buf[0] == '@')
			(*tail)->symref = xstrdup(buf.buf + 1);
		else if (buf.buf[0] != '?')
			get_sha1_hex(buf.buf, (*tail)->old_sha1);
		if (eon) {
			if (has_attribute(eon + 1, "unchanged")) {
				(*tail)->status |= REF_STATUS_UPTODATE;
				read_ref((*tail)->name, (*tail)->old_sha1);
			}
		}
		tail = &((*tail)->next);
	}
	strbuf_release(&buf);

	for (posn = ret; posn; posn = posn->next)
		resolve_remote_symref(posn, ret);

	return ret;
}

int transport_helper_init(struct transport *transport, const char *name)
{
	struct helper_data *data = xcalloc(sizeof(*data), 1);
	data->name = name;

	transport->data = data;
	transport->get_refs_list = get_refs_list;
	transport->fetch = fetch;
	transport->disconnect = release_helper;
	return 0;
}