upload-pack: Run rev-list in an asynchronous function.

This gets rid of an explicit fork().

Since upload-pack has to coordinate two processes (rev-list and
pack-objects), we cannot use the normal finish_async(), but have to monitor
the process explicitly. Hence, there are no changes at this front.

Signed-off-by: Johannes Sixt <johannes.sixt@telecom.at>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

diff --git a/upload-pack.c b/upload-pack.c
index ccdc30653bdede85d351e55bb1360c3049b05fef..67994680f2f48e573f78c592c853422e6d8995cf 100644 (file)
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -97,11 +97,12 @@ static void show_edge(struct commit *commit)
        fprintf(pack_pipe, "-%s\n", sha1_to_hex(commit->object.sha1));
 }
 
-static void do_rev_list(int create_full_pack)
+static int do_rev_list(int fd, void *create_full_pack)
 {
        int i;
        struct rev_info revs;
 
+       pack_pipe = fdopen(fd, "w");
        if (create_full_pack)
                use_thin_pack = 0; /* no point doing it */
        init_revisions(&revs, NULL);
@@ -131,14 +132,12 @@ static void do_rev_list(int create_full_pack)
        prepare_revision_walk(&revs);
        mark_edges_uninteresting(revs.commits, &revs, show_edge);
        traverse_commit_list(&revs, show_commit, show_object);
+       return 0;
 }
 
 static void create_pack_file(void)
 {
-       /* Pipe from rev-list to pack-objects
-        */
-       int lp_pipe[2];
-       pid_t pid_rev_list;
+       struct async rev_list;
        struct child_process pack_objects;
        int create_full_pack = (nr_our_refs == want_obj.nr && !have_obj.nr);
        char data[8193], progress[128];
@@ -148,22 +147,12 @@ static void create_pack_file(void)
        const char *argv[10];
        int arg = 0;
 
-       if (pipe(lp_pipe) < 0)
-               die("git-upload-pack: unable to create pipe");
-       pid_rev_list = fork();
-       if (pid_rev_list < 0)
+       rev_list.proc = do_rev_list;
+       /* .data is just a boolean: any non-NULL value will do */
+       rev_list.data = create_full_pack ? &rev_list : NULL;
+       if (start_async(&rev_list))
                die("git-upload-pack: unable to fork git-rev-list");
 
-       if (!pid_rev_list) {
-               close(lp_pipe[0]);
-               pack_pipe = fdopen(lp_pipe[1], "w");
-               do_rev_list(create_full_pack);
-               exit(0);
-       }
-
-       /* writable pipe end must not be inherited by pack_objects */
-       close(lp_pipe[1]);
-
        argv[arg++] = "pack-objects";
        argv[arg++] = "--stdout";
        if (!no_progress)
@@ -173,14 +162,15 @@ static void create_pack_file(void)
        argv[arg++] = NULL;
 
        memset(&pack_objects, 0, sizeof(pack_objects));
-       pack_objects.in = lp_pipe[0];   /* start_command closes it */
+       pack_objects.in = rev_list.out; /* start_command closes it */
        pack_objects.out = -1;
        pack_objects.err = -1;
        pack_objects.git_cmd = 1;
        pack_objects.argv = argv;
+
        if (start_command(&pack_objects)) {
                /* daemon sets things up to ignore TERM */
-               kill(pid_rev_list, SIGKILL);
+               kill(rev_list.pid, SIGKILL);
                die("git-upload-pack: unable to fork git-pack-objects");
        }
 
@@ -280,11 +270,11 @@ static void create_pack_file(void)
                }
 
                /* See if the children are still there */
-               if (pid_rev_list || pack_objects.pid) {
+               if (rev_list.pid || pack_objects.pid) {
                        pid = waitpid(-1, &status, WNOHANG);
                        if (!pid)
                                continue;
-                       who = ((pid == pid_rev_list) ? "git-rev-list" :
+                       who = ((pid == rev_list.pid) ? "git-rev-list" :
                               (pid == pack_objects.pid) ? "git-pack-objects" :
                               NULL);
                        if (!who) {
@@ -302,11 +292,11 @@ static void create_pack_file(void)
                                      who);
                                goto fail;
                        }
-                       if (pid == pid_rev_list)
-                               pid_rev_list = 0;
+                       if (pid == rev_list.pid)
+                               rev_list.pid = 0;
                        if (pid == pack_objects.pid)
                                pack_objects.pid = 0;
-                       if (pid_rev_list || pack_objects.pid)
+                       if (rev_list.pid || pack_objects.pid)
                                continue;
                }
 
@@ -329,8 +319,8 @@ static void create_pack_file(void)
  fail:
        if (pack_objects.pid)
                kill(pack_objects.pid, SIGKILL);
-       if (pid_rev_list)
-               kill(pid_rev_list, SIGKILL);
+       if (rev_list.pid)
+               kill(rev_list.pid, SIGKILL);
        send_client_data(3, abort_msg, sizeof(abort_msg));
        die("git-upload-pack: %s", abort_msg);
 }