+ char *url, *posn;
+ char hex[42];
+ struct buffer buffer;
+ buffer.size = 41;
+ buffer.posn = 0;
+ buffer.buffer = hex;
+ hex[41] = '\0';
+
+ curl_easy_setopt(curl, CURLOPT_FILE, &buffer);
+ curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
+
+ url = xmalloc(strlen(base) + 6 + strlen(ref));
+ strcpy(url, base);
+ posn = url + strlen(base);
+ strcpy(posn, "refs/");
+ posn += 5;
+ strcpy(posn, ref);
+
+ curl_easy_setopt(curl, CURLOPT_URL, url);
+
+ if (curl_easy_perform(curl))
+ return error("Couldn't get %s for %s\n", url, ref);
+
+ hex[40] = '\0';
+ get_sha1_hex(hex, sha1);
+ return 0;