Fix for multiple alternates requests in http-fetch
Stop additional alternates requests from starting if one is already in
progress. This adds an optional callback which is processed after a slot
has finished running.
Signed-off-by: Nick Hengeveld <nickh@reactrix.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/http-fetch.c b/http-fetch.c
index f39e748..99b6cc7 100644
--- a/http-fetch.c
+++ b/http-fetch.c
@@ -25,7 +25,7 @@
#define PREV_BUF_SIZE 4096
#define RANGE_HEADER_SIZE 30
-static int got_alternates = 0;
+static int got_alternates = -1;
static int active_requests = 0;
static int data_received;
@@ -87,9 +87,19 @@
int done;
CURLcode curl_result;
long http_code;
+ void *callback_data;
+ void (*callback_func)(void *data);
struct active_request_slot *next;
};
+struct alt_request {
+ char *base;
+ char *url;
+ struct buffer *buffer;
+ struct active_request_slot *slot;
+ int http_specific;
+};
+
static struct transfer_request *request_queue_head = NULL;
static struct active_request_slot *active_queue_head = NULL;
@@ -237,7 +247,7 @@
static void process_curl_messages(void);
static void process_request_queue(void);
#endif
-static int fetch_alternates(char *base);
+static void fetch_alternates(char *base);
static CURL* get_curl_handle(void)
{
@@ -324,6 +334,8 @@
slot->in_use = 1;
slot->done = 0;
slot->local = NULL;
+ slot->callback_data = NULL;
+ slot->callback_func = NULL;
curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, pragma_header);
curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_range_header);
curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, curl_errorstr);
@@ -601,6 +613,12 @@
} else {
fprintf(stderr, "Received DONE message for unknown request!\n");
}
+
+ /* Process slot callback if appropriate */
+ if (slot->callback_func != NULL) {
+ slot->callback_func(slot->callback_data);
+ }
+
if (request != NULL) {
request->curl_result = curl_result;
request->http_code = slot->http_code;
@@ -766,72 +784,51 @@
return 0;
}
-static int fetch_alternates(char *base)
+static void process_alternates(void *callback_data)
{
- int ret = 0;
- struct buffer buffer;
- char *url;
+ struct alt_request *alt_req = (struct alt_request *)callback_data;
+ struct active_request_slot *slot = alt_req->slot;
+ struct alt_base *tail = alt;
+ char *base = alt_req->base;
+ static const char null_byte = '\0';
char *data;
int i = 0;
- int http_specific = 1;
- struct alt_base *tail = alt;
- static const char null_byte = '\0';
- struct active_request_slot *slot;
+ if (alt_req->http_specific) {
+ if (slot->curl_result != CURLE_OK ||
+ !alt_req->buffer->posn) {
- if (got_alternates)
- return 0;
-
- data = xmalloc(4096);
- buffer.size = 4096;
- buffer.posn = 0;
- buffer.buffer = data;
-
- if (get_verbosely)
- fprintf(stderr, "Getting alternates list for %s\n", base);
-
- url = xmalloc(strlen(base) + 31);
- sprintf(url, "%s/objects/info/http-alternates", base);
-
- slot = get_active_slot();
- curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
- curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
- fwrite_buffer_dynamic);
- curl_easy_setopt(slot->curl, CURLOPT_URL, url);
- if (start_active_slot(slot)) {
- run_active_slot(slot);
- if (slot->curl_result != CURLE_OK || !buffer.posn) {
- http_specific = 0;
-
- sprintf(url, "%s/objects/info/alternates", base);
-
- slot = get_active_slot();
- curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
- curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
- fwrite_buffer_dynamic);
- curl_easy_setopt(slot->curl, CURLOPT_URL, url);
+ /* Try reusing the slot to get non-http alternates */
+ alt_req->http_specific = 0;
+ sprintf(alt_req->url, "%s/objects/info/alternates",
+ base);
+ curl_easy_setopt(slot->curl, CURLOPT_URL,
+ alt_req->url);
+ active_requests++;
+ slot->in_use = 1;
+ slot->done = 0;
if (start_active_slot(slot)) {
- run_active_slot(slot);
- if (slot->curl_result != CURLE_OK) {
- free(buffer.buffer);
- if (slot->http_code == 404)
- got_alternates = 1;
- return 0;
- }
+ return;
+ } else {
+ got_alternates = -1;
+ slot->done = 1;
+ return;
}
}
- } else {
- free(buffer.buffer);
- return 0;
+ } else if (slot->curl_result != CURLE_OK) {
+ if (slot->http_code != 404) {
+ got_alternates = -1;
+ return;
+ }
}
- fwrite_buffer_dynamic(&null_byte, 1, 1, &buffer);
- buffer.posn--;
- data = buffer.buffer;
+ fwrite_buffer_dynamic(&null_byte, 1, 1, alt_req->buffer);
+ alt_req->buffer->posn--;
+ data = alt_req->buffer->buffer;
- while (i < buffer.posn) {
+ while (i < alt_req->buffer->posn) {
int posn = i;
- while (posn < buffer.posn && data[posn] != '\n')
+ while (posn < alt_req->buffer->posn && data[posn] != '\n')
posn++;
if (data[posn] == '\n') {
int okay = 0;
@@ -855,7 +852,7 @@
// If the server got removed, give up.
okay = strchr(base, ':') - base + 3 <
serverlen;
- } else if (http_specific) {
+ } else if (alt_req->http_specific) {
char *colon = strchr(data + i, ':');
char *slash = strchr(data + i, '/');
if (colon && slash && colon < data + posn &&
@@ -881,15 +878,74 @@
while (tail->next != NULL)
tail = tail->next;
tail->next = newalt;
- ret++;
}
}
i = posn + 1;
}
got_alternates = 1;
- free(buffer.buffer);
- return ret;
+}
+
+static void fetch_alternates(char *base)
+{
+ struct buffer buffer;
+ char *url;
+ char *data;
+ struct active_request_slot *slot;
+ static struct alt_request alt_req;
+ int num_transfers;
+
+ /* If another request has already started fetching alternates,
+ wait for them to arrive and return to processing this request's
+ curl message */
+ while (got_alternates == 0) {
+ curl_multi_perform(curlm, &num_transfers);
+ process_curl_messages();
+ process_request_queue();
+ }
+
+ /* Nothing to do if they've already been fetched */
+ if (got_alternates == 1)
+ return;
+
+ /* Start the fetch */
+ got_alternates = 0;
+
+ data = xmalloc(4096);
+ buffer.size = 4096;
+ buffer.posn = 0;
+ buffer.buffer = data;
+
+ if (get_verbosely)
+ fprintf(stderr, "Getting alternates list for %s\n", base);
+
+ url = xmalloc(strlen(base) + 31);
+ sprintf(url, "%s/objects/info/http-alternates", base);
+
+ /* Use a callback to process the result, since another request
+ may fail and need to have alternates loaded before continuing */
+ slot = get_active_slot();
+ slot->callback_func = process_alternates;
+ slot->callback_data = &alt_req;
+
+ curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
+ curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
+ fwrite_buffer_dynamic);
+ curl_easy_setopt(slot->curl, CURLOPT_URL, url);
+
+ alt_req.base = base;
+ alt_req.url = url;
+ alt_req.buffer = &buffer;
+ alt_req.http_specific = 1;
+ alt_req.slot = slot;
+
+ if (start_active_slot(slot))
+ run_active_slot(slot);
+ else
+ got_alternates = -1;
+
+ free(data);
+ free(url);
}
static int fetch_indices(struct alt_base *repo)
