[PATCH] Limit the number of requests outstanding in ssh-fetch.

This completes fetches if there are more than 100 outstanding requests
and there are more to prefetch.

Signed-off-by: Daniel Barkalow <barkalow@iabervon.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/ssh-fetch.c b/ssh-fetch.c
index 05d3e49..bf01fbc 100644 (file)
--- a/ssh-fetch.c
+++ b/ssh-fetch.c
@@ -36,12 +36,26 @@ static ssize_t force_write(int fd, void *buffer, size_t length)
        return ret;
 }
 
+static int prefetches = 0;
+
+static struct object_list *in_transit = NULL;
+static struct object_list **end_of_transit = &in_transit;
+
 void prefetch(unsigned char *sha1)
 {
        char type = 'o';
+       struct object_list *node;
+       if (prefetches > 100) {
+               fetch(in_transit->item->sha1);
+       }
+       node = xmalloc(sizeof(struct object_list));
+       node->next = NULL;
+       node->item = lookup_unknown_object(sha1);
+       *end_of_transit = node;
+       end_of_transit = &node->next;
        force_write(fd_out, &type, 1);
        force_write(fd_out, sha1, 20);
-       //memcpy(requested + 20 * prefetches++, sha1, 20);
+       prefetches++;
 }
 
 static char conn_buf[4096];
@@ -51,6 +65,18 @@ int fetch(unsigned char *sha1)
 {
        int ret;
        signed char remote;
+       struct object_list *temp;
+
+       if (memcmp(sha1, in_transit->item->sha1, 20)) {
+               // we must have already fetched it to clean the queue
+               return has_sha1_file(sha1) ? 0 : -1;
+       }
+       prefetches--;
+       temp = in_transit;
+       in_transit = in_transit->next;
+       if (!in_transit)
+               end_of_transit = &in_transit;
+       free(temp);
 
        if (conn_buf_posn) {
                remote = conn_buf[0];