http*: add http_get_info_packs

http-push.c and http-walker.c no longer have to use fetch_index or
setup_index; they simply need to use http_get_info_packs, a new http
method, in their fetch_indices implementations.

Move fetch_index() and rename to fetch_pack_index() in http.c; this
method is not meant to be used outside of http.c. It invokes
end_url_with_slash with base_url; apart from that change, the code is
identical.

Move setup_index() and rename to fetch_and_setup_pack_index() in
http.c; this method is not meant to be used outside of http.c.

Do not immediately set ret to 0 in http-walker.c::fetch_indices();
instead do it in the HTTP_MISSING_TARGET case, to make it clear that
the HTTP_OK and HTTP_MISSING_TARGET cases both return 0.

Signed-off-by: Tay Ray Chuan <rctay89@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 164 insertions, 0 deletions

diff --git a/http.c b/http.c
index 2a4937201..96d83d5c3 100644
--- a/http.c
+++ b/http.c
@@ -790,3 +790,167 @@ int http_fetch_ref(const char *base, struct ref *ref)
 	free(url);
 	return ret;
 }
+
+/* Helpers for fetching packs */
+static int fetch_pack_index(unsigned char *sha1, const char *base_url)
+{
+	int ret = 0;
+	char *hex = xstrdup(sha1_to_hex(sha1));
+	char *filename;
+	char *url;
+	char tmpfile[PATH_MAX];
+	long prev_posn = 0;
+	char range[RANGE_HEADER_SIZE];
+	struct strbuf buf = STRBUF_INIT;
+	struct curl_slist *range_header = NULL;
+
+	FILE *indexfile;
+	struct active_request_slot *slot;
+	struct slot_results results;
+
+	/* Don't use the index if the pack isn't there */
+	end_url_with_slash(&buf, base_url);
+	strbuf_addf(&buf, "objects/pack/pack-%s.pack", hex);
+	url = strbuf_detach(&buf, 0);
+
+	slot = get_active_slot();
+	slot->results = &results;
+	curl_easy_setopt(slot->curl, CURLOPT_URL, url);
+	curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 1);
+	if (start_active_slot(slot)) {
+		run_active_slot(slot);
+		if (results.curl_result != CURLE_OK) {
+			ret = error("Unable to verify pack %s is available",
+				    hex);
+			goto cleanup_pack;
+		}
+	} else {
+		ret = error("Unable to start request");
+		goto cleanup_pack;
+	}
+
+	if (has_pack_index(sha1)) {
+		ret = 0;
+		goto cleanup_pack;
+	}
+
+	if (http_is_verbose)
+		fprintf(stderr, "Getting index for pack %s\n", hex);
+
+	end_url_with_slash(&buf, base_url);
+	strbuf_addf(&buf, "objects/pack/pack-%s.idx", hex);
+	url = strbuf_detach(&buf, NULL);
+
+	filename = sha1_pack_index_name(sha1);
+	snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
+	indexfile = fopen(tmpfile, "a");
+	if (!indexfile) {
+		ret = error("Unable to open local file %s for pack index",
+			    tmpfile);
+		goto cleanup_pack;
+	}
+
+	slot = get_active_slot();
+	slot->results = &results;
+	curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 0);
+	curl_easy_setopt(slot->curl, CURLOPT_HTTPGET, 1);
+	curl_easy_setopt(slot->curl, CURLOPT_FILE, indexfile);
+	curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
+	curl_easy_setopt(slot->curl, CURLOPT_URL, url);
+	curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
+	slot->local = indexfile;
+
+	/*
+	 * If there is data present from a previous transfer attempt,
+	 * resume where it left off
+	 */
+	prev_posn = ftell(indexfile);
+	if (prev_posn>0) {
+		if (http_is_verbose)
+			fprintf(stderr,
+				"Resuming fetch of index for pack %s at byte %ld\n",
+				hex, prev_posn);
+		sprintf(range, "Range: bytes=%ld-", prev_posn);
+		range_header = curl_slist_append(range_header, range);
+		curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
+	}
+
+	if (start_active_slot(slot)) {
+		run_active_slot(slot);
+		if (results.curl_result != CURLE_OK) {
+			ret = error("Unable to get pack index %s\n%s",
+				    url, curl_errorstr);
+			goto cleanup_index;
+		}
+	} else {
+		ret = error("Unable to start request");
+		goto cleanup_index;
+	}
+
+	ret = move_temp_to_file(tmpfile, filename);
+
+cleanup_index:
+	fclose(indexfile);
+	slot->local = NULL;
+cleanup_pack:
+	free(hex);
+	free(url);
+	return ret;
+}
+
+static int fetch_and_setup_pack_index(struct packed_git **packs_head,
+	unsigned char *sha1, const char *base_url)
+{
+	struct packed_git *new_pack;
+
+	if (fetch_pack_index(sha1, base_url))
+		return -1;
+
+	new_pack = parse_pack_index(sha1);
+	if (!new_pack)
+		return -1; /* parse_pack_index() already issued error message */
+	new_pack->next = *packs_head;
+	*packs_head = new_pack;
+	return 0;
+}
+
+int http_get_info_packs(const char *base_url, struct packed_git **packs_head)
+{
+	int ret = 0, i = 0;
+	char *url, *data;
+	struct strbuf buf = STRBUF_INIT;
+	unsigned char sha1[20];
+
+	end_url_with_slash(&buf, base_url);
+	strbuf_addstr(&buf, "objects/info/packs");
+	url = strbuf_detach(&buf, NULL);
+
+	ret = http_get_strbuf(url, &buf, HTTP_NO_CACHE);
+	if (ret != HTTP_OK)
+		goto cleanup;
+
+	data = buf.buf;
+	while (i < buf.len) {
+		switch (data[i]) {
+		case 'P':
+			i++;
+			if (i + 52 <= buf.len &&
+			    !prefixcmp(data + i, " pack-") &&
+			    !prefixcmp(data + i + 46, ".pack\n")) {
+				get_sha1_hex(data + i + 6, sha1);
+				fetch_and_setup_pack_index(packs_head, sha1,
+						      base_url);
+				i += 51;
+				break;
+			}
+		default:
+			while (i < buf.len && data[i] != '\n')
+				i++;
+		}
+		i++;
+	}
+
+cleanup:
+	free(url);
+	return ret;
+}