1 files changed, 144 insertions, 0 deletions
diff --git a/fetch-pack.c b/fetch-pack.c
new file mode 100644
index 0000000000..65e007639a
--- /dev/null
+++ b/fetch-pack.c
@@ -0,0 +1,144 @@
+#include "cache.h"
+#include "refs.h"
+#include "pkt-line.h"
+#include <sys/wait.h>
+
+static int quiet;
+static const char fetch_pack_usage[] = "git-fetch-pack [-q] [--exec=upload-pack] [host:]directory [heads]* < mycommitlist";
+static const char *exec = "git-upload-pack";
+
+static int find_common(int fd[2], unsigned char *result_sha1, unsigned char *remote)
+{
+	static char line[1000];
+	int count = 0, flushes = 0, retval;
+	FILE *revs;
+
+	revs = popen("git-rev-list $(git-rev-parse --all)", "r");
+	if (!revs)
+		die("unable to run 'git-rev-list'");
+	packet_write(fd[1], "want %s\n", sha1_to_hex(remote));
+	packet_flush(fd[1]);
+	flushes = 1;
+	retval = -1;
+	while (fgets(line, sizeof(line), revs) != NULL) {
+		unsigned char sha1[20];
+		if (get_sha1_hex(line, sha1))
+			die("git-fetch-pack: expected object name, got crud");
+		packet_write(fd[1], "have %s\n", sha1_to_hex(sha1));
+		if (!(31 & ++count)) {
+			packet_flush(fd[1]);
+			flushes++;
+
+			/*
+			 * We keep one window "ahead" of the other side, and
+			 * will wait for an ACK only on the next one
+			 */
+			if (count == 32)
+				continue;
+			if (get_ack(fd[0], result_sha1)) {
+				flushes = 0;
+				retval = 0;
+				break;
+			}
+			flushes--;
+		}
+	}
+	pclose(revs);
+	packet_write(fd[1], "done\n");
+	while (flushes) {
+		flushes--;
+		if (get_ack(fd[0], result_sha1))
+			return 0;
+	}
+	return retval;
+}
+
+/*
+ * Eventually we'll want to be able to fetch multiple heads.
+ *
+ * Right now we'll just require a single match.
+ */
+static int fetch_pack(int fd[2], int nr_match, char **match)
+{
+	struct ref *ref;
+	unsigned char sha1[20];
+	int status;
+	pid_t pid;
+
+	get_remote_heads(fd[0], &ref, nr_match, match);
+	if (!ref) {
+		packet_flush(fd[1]);
+		die("no matching remote head");
+	}
+	if (ref->next) {
+		packet_flush(fd[1]);
+		die("multiple remote heads");
+	}
+	if (find_common(fd, sha1, ref->old_sha1) < 0)
+		die("git-fetch-pack: no common commits");
+	pid = fork();
+	if (pid < 0)
+		die("git-fetch-pack: unable to fork off git-unpack-objects");
+	if (!pid) {
+		dup2(fd[0], 0);
+		close(fd[0]);
+		close(fd[1]);
+		execlp("git-unpack-objects", "git-unpack-objects",
+		       quiet ? "-q" : NULL, NULL);
+		die("git-unpack-objects exec failed");
+	}
+	close(fd[0]);
+	close(fd[1]);
+	while (waitpid(pid, &status, 0) < 0) {
+		if (errno != EINTR)
+			die("waiting for git-unpack-objects: %s", strerror(errno));
+	}
+	if (WIFEXITED(status)) {
+		int code = WEXITSTATUS(status);
+		if (code)
+			die("git-unpack-objects died with error code %d", code);
+		puts(sha1_to_hex(ref->old_sha1));
+		return 0;
+	}
+	if (WIFSIGNALED(status)) {
+		int sig = WTERMSIG(status);
+		die("git-unpack-objects died of signal %d", sig);
+	}
+	die("Sherlock Holmes! git-unpack-objects died of unnatural causes %d!", status);
+}
+
+int main(int argc, char **argv)
+{
+	int i, ret, nr_heads;
+	char *dest = NULL, **heads;
+	int fd[2];
+	pid_t pid;
+
+	nr_heads = 0;
+	heads = NULL;
+	for (i = 1; i < argc; i++) {
+		char *arg = argv[i];
+
+		if (*arg == '-') {
+			if (!strncmp("--exec=", arg, 7)) {
+				exec = arg + 7;
+				continue;
+			}
+			usage(fetch_pack_usage);
+		}
+		dest = arg;
+		heads = argv + i + 1;
+		nr_heads = argc - i - 1;
+		break;
+	}
+	if (!dest)
+		usage(fetch_pack_usage);
+	pid = git_connect(fd, dest, exec);
+	if (pid < 0)
+		return 1;
+	ret = fetch_pack(fd, nr_heads, heads);
+	close(fd[0]);
+	close(fd[1]);
+	finish_connect(pid);
+	return ret;
+}