transport_get() can call transport_native_helper_init() to have list and
fetch-ref operations handled by running a separate program as:
git remote-<something> <remote> [<url>]
This program then accepts, on its stdin, "list" and "fetch <hex>
<name>" commands; the former prints out a list of available refs and
either their hashes or what they are symrefs to, while the latter
fetches them into the local object database and prints a newline when done.
Signed-off-by: Daniel Barkalow <barkalow@xxxxxxxxxxxx>
---
Documentation/git-remote-helpers.txt | 71 ++++++++++++++
Makefile | 1 +
transport-helper.c | 168 ++++++++++++++++++++++++++++++++++
transport.h | 3 +
4 files changed, 243 insertions(+), 0 deletions(-)
create mode 100644 Documentation/git-remote-helpers.txt
create mode 100644 transport-helper.c
diff --git a/Documentation/git-remote-helpers.txt b/Documentation/git-remote-helpers.txt
new file mode 100644
index 0000000..173ee23
--- /dev/null
+++ b/Documentation/git-remote-helpers.txt
@@ -0,0 +1,71 @@
+git-remote-helpers(1)
+=====================
+
+NAME
+----
+git-remote-helpers - Helper programs for interoperation with remote git
+
+SYNOPSIS
+--------
+'git remote-<transport>' <remote>
+
+DESCRIPTION
+-----------
+
+These programs are normally not used directly by end users, but are
+invoked by various git programs that interact with remote repositories
+when the repository they would operate on will be accessed using
+transport code not linked into the main git binary. Various particular
+helper programs will behave as documented here.
+
+COMMANDS
+--------
+
+Commands are given by the caller on the helper's standard input, one per line.
+
+'capabilities'::
+ Lists the capabilities of the helper, one per line, ending
+ with a blank line.
+
+'list'::
+ Lists the refs, one per line, in the format "<value> <name>
+ [<attr> ...]". The value may be a hex sha1 hash, "@<dest>" for
+ a symref, or "?" to indicate that the helper could not get the
+ value of the ref. A space-separated list of attributes follows
+ the name; unrecognized attributes are ignored. After the
+ complete list, outputs a blank line.
+
+'fetch' <sha1> <name>::
+ Fetches the given object, writing the necessary objects to the
+ database. Outputs a blank line when the fetch is
+ complete. Only objects which were reported in the ref list
+ with a sha1 may be fetched this way.
++
+Supported if the helper has the "fetch" capability.
+
+If a fatal error occurs, the program writes the error message to
+stderr and exits. The caller should expect that a suitable error
+message has been printed if the child closes the connection without
+completing a valid response for the current command.
+
+Additional commands may be supported, as may be determined from
+capabilities reported by the helper.
+
+CAPABILITIES
+------------
+
+'fetch'::
+ This helper supports the 'fetch' command.
+
+REF LIST ATTRIBUTES
+-------------------
+
+None are defined yet, but the caller must accept any which are supplied.
+
+Documentation
+-------------
+Documentation by Daniel Barkalow.
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Makefile b/Makefile
index daf4296..504646a 100644
--- a/Makefile
+++ b/Makefile
@@ -549,6 +549,7 @@ LIB_OBJS += symlinks.o
LIB_OBJS += tag.o
LIB_OBJS += trace.o
LIB_OBJS += transport.o
+LIB_OBJS += transport-helper.o
LIB_OBJS += tree-diff.o
LIB_OBJS += tree.o
LIB_OBJS += tree-walk.o
diff --git a/transport-helper.c b/transport-helper.c
new file mode 100644
index 0000000..0d19c6c
--- /dev/null
+++ b/transport-helper.c
@@ -0,0 +1,168 @@
+#include "cache.h"
+#include "transport.h"
+
+#include "run-command.h"
+#include "commit.h"
+#include "diff.h"
+#include "revision.h"
+
+struct helper_data
+{
+ const char *name;
+ struct child_process *helper;
+ unsigned fetch : 1;
+};
+
+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;
+
+ 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_in_full(data->helper->in, "capabilities\n", 13);
+ file = fdopen(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;
+ }
+ return data->helper;
+}
+
+static int disconnect_helper(struct transport *transport)
+{
+ struct helper_data *data = transport->data;
+ if (data->helper) {
+ write_in_full(data->helper->in, "\n", 1);
+ 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 fetch_with_fetch(struct transport *transport,
+ int nr_heads, const struct ref **to_fetch)
+{
+ struct child_process *helper = get_helper(transport);
+ FILE *file = fdopen(helper->out, "r");
+ int i;
+ struct strbuf buf = STRBUF_INIT;
+
+ for (i = 0; i < nr_heads; i++) {
+ struct ref *posn = to_fetch[i];
+ if (posn->status & REF_STATUS_UPTODATE)
+ continue;
+ write_in_full(helper->in, "fetch ", 6);
+ write_in_full(helper->in, sha1_to_hex(posn->old_sha1), 40);
+ write_in_full(helper->in, " ", 1);
+ write_in_full(helper->in, posn->name, strlen(posn->name));
+ write_in_full(helper->in, "\n", 1);
+ if (strbuf_getline(&buf, file, '\n') == EOF)
+ exit(128); /* child died, message supplied already */
+ }
+ return 0;
+}
+
+static int fetch(struct transport *transport,
+ int nr_heads, const 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);
+
+ return -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_in_full(helper->in, "list\n", 5);
+
+ file = fdopen(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);
+ 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)
+{
+ struct helper_data *data = xcalloc(sizeof(*data), 1);
+ char *eom = strchr(transport->url, ':');
+ if (!eom)
+ return -1;
+ data->name = xstrndup(transport->url, eom - transport->url);
+
+ transport->data = data;
+ transport->get_refs_list = get_refs_list;
+ transport->fetch = fetch;
+ transport->disconnect = disconnect_helper;
+ return 0;
+}
diff --git a/transport.h b/transport.h
index 51b5397..df87264 100644
--- a/transport.h
+++ b/transport.h
@@ -77,4 +77,7 @@ void transport_unlock_pack(struct transport *transport);
int transport_disconnect(struct transport *transport);
char *transport_anonymize_url(const char *url);
+/* Transport methods defined outside transport.c */
+int transport_helper_init(struct transport *transport);
+
#endif
--
1.6.4.rc3.27.g95032.dirty
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