Merge branch 'ew/http-walker' into jk/http-walker-limit-redirect

* ew/http-walker:
  list: avoid incompatibility with *BSD sys/queue.h
  http-walker: reduce O(n) ops with doubly-linked list
  http: avoid disconnecting on 404s for loose objects
  http-walker: remove unused parameter from fetch_object

3 files changed, 206 insertions, 31 deletions

diff --git a/http-walker.c b/http-walker.c
index 4bff31c444..25a8b1ad4b 100644
--- a/http-walker.c
+++ b/http-walker.c
@@ -2,6 +2,7 @@
 #include "commit.h"
 #include "walker.h"
 #include "http.h"
+#include "list.h"
 
 struct alt_base {
 	char *base;
@@ -23,7 +24,7 @@ struct object_request {
 	struct alt_base *repo;
 	enum object_request_state state;
 	struct http_object_request *req;
-	struct object_request *next;
+	struct list_head node;
 };
 
 struct alternates_request {
@@ -41,7 +42,7 @@ struct walker_data {
 	struct alt_base *alt;
 };
 
-static struct object_request *object_queue_head;
+static LIST_HEAD(object_queue_head);
 
 static void fetch_alternates(struct walker *walker, const char *base);
 
@@ -110,19 +111,10 @@ static void process_object_response(void *callback_data)
 
 static void release_object_request(struct object_request *obj_req)
 {
-	struct object_request *entry = object_queue_head;
-
 	if (obj_req->req !=NULL && obj_req->req->localfile != -1)
 		error("fd leakage in release: %d", obj_req->req->localfile);
-	if (obj_req == object_queue_head) {
-		object_queue_head = obj_req->next;
-	} else {
-		while (entry->next != NULL && entry->next != obj_req)
-			entry = entry->next;
-		if (entry->next == obj_req)
-			entry->next = entry->next->next;
-	}
 
+	list_del(&obj_req->node);
 	free(obj_req);
 }
 
@@ -130,8 +122,10 @@ static void release_object_request(struct object_request *obj_req)
 static int fill_active_slot(struct walker *walker)
 {
 	struct object_request *obj_req;
+	struct list_head *pos, *tmp, *head = &object_queue_head;
 
-	for (obj_req = object_queue_head; obj_req; obj_req = obj_req->next) {
+	list_for_each_safe(pos, tmp, head) {
+		obj_req = list_entry(pos, struct object_request, node);
 		if (obj_req->state == WAITING) {
 			if (has_sha1_file(obj_req->sha1))
 				obj_req->state = COMPLETE;
@@ -148,7 +142,6 @@ static int fill_active_slot(struct walker *walker)
 static void prefetch(struct walker *walker, unsigned char *sha1)
 {
 	struct object_request *newreq;
-	struct object_request *tail;
 	struct walker_data *data = walker->data;
 
 	newreq = xmalloc(sizeof(*newreq));
@@ -157,18 +150,9 @@ static void prefetch(struct walker *walker, unsigned char *sha1)
 	newreq->repo = data->alt;
 	newreq->state = WAITING;
 	newreq->req = NULL;
-	newreq->next = NULL;
 
 	http_is_verbose = walker->get_verbosely;
-
-	if (object_queue_head == NULL) {
-		object_queue_head = newreq;
-	} else {
-		tail = object_queue_head;
-		while (tail->next != NULL)
-			tail = tail->next;
-		tail->next = newreq;
-	}
+	list_add_tail(&newreq->node, &object_queue_head);
 
 #ifdef USE_CURL_MULTI
 	fill_active_slots();
@@ -449,15 +433,19 @@ static void abort_object_request(struct object_request *obj_req)
 	release_object_request(obj_req);
 }
 
-static int fetch_object(struct walker *walker, struct alt_base *repo, unsigned char *sha1)
+static int fetch_object(struct walker *walker, unsigned char *sha1)
 {
 	char *hex = sha1_to_hex(sha1);
 	int ret = 0;
-	struct object_request *obj_req = object_queue_head;
+	struct object_request *obj_req = NULL;
 	struct http_object_request *req;
+	struct list_head *pos, *head = &object_queue_head;
 
-	while (obj_req != NULL && hashcmp(obj_req->sha1, sha1))
-		obj_req = obj_req->next;
+	list_for_each(pos, head) {
+		obj_req = list_entry(pos, struct object_request, node);
+		if (!hashcmp(obj_req->sha1, sha1))
+			break;
+	}
 	if (obj_req == NULL)
 		return error("Couldn't find request for %s in the queue", hex);
 
@@ -490,6 +478,15 @@ static int fetch_object(struct walker *walker, struct alt_base *repo, unsigned c
 		req->localfile = -1;
 	}
 
+	/*
+	 * we turned off CURLOPT_FAILONERROR to avoid losing a
+	 * persistent connection and got CURLE_OK.
+	 */
+	if (req->http_code == 404 && req->curl_result == CURLE_OK &&
+			(starts_with(req->url, "http://") ||
+			 starts_with(req->url, "https://")))
+		req->curl_result = CURLE_HTTP_RETURNED_ERROR;
+
 	if (obj_req->state == ABORTED) {
 		ret = error("Request for %s aborted", hex);
 	} else if (req->curl_result != CURLE_OK &&
@@ -520,7 +517,7 @@ static int fetch(struct walker *walker, unsigned char *sha1)
 	struct walker_data *data = walker->data;
 	struct alt_base *altbase = data->alt;
 
-	if (!fetch_object(walker, altbase, sha1))
+	if (!fetch_object(walker, sha1))
 		return 0;
 	while (altbase) {
 		if (!http_fetch_pack(walker, altbase, sha1))
diff --git a/http.c b/http.c
index a9778bfa44..7b66519b67 100644
--- a/http.c
+++ b/http.c
@@ -1885,8 +1885,19 @@ static size_t fwrite_sha1_file(char *ptr, size_t eltsize, size_t nmemb,
 	unsigned char expn[4096];
 	size_t size = eltsize * nmemb;
 	int posn = 0;
-	struct http_object_request *freq =
-		(struct http_object_request *)data;
+	struct http_object_request *freq = data;
+	struct active_request_slot *slot = freq->slot;
+
+	if (slot) {
+		CURLcode c = curl_easy_getinfo(slot->curl, CURLINFO_HTTP_CODE,
+						&slot->http_code);
+		if (c != CURLE_OK)
+			die("BUG: curl_easy_getinfo for HTTP code failed: %s",
+				curl_easy_strerror(c));
+		if (slot->http_code >= 400)
+			return size;
+	}
+
 	do {
 		ssize_t retval = xwrite(freq->localfile,
 					(char *) ptr + posn, size - posn);
@@ -2007,6 +2018,7 @@ struct http_object_request *new_http_object_request(const char *base_url,
 	freq->slot = get_active_slot();
 
 	curl_easy_setopt(freq->slot->curl, CURLOPT_FILE, freq);
+	curl_easy_setopt(freq->slot->curl, CURLOPT_FAILONERROR, 0);
 	curl_easy_setopt(freq->slot->curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);
 	curl_easy_setopt(freq->slot->curl, CURLOPT_ERRORBUFFER, freq->errorstr);
 	curl_easy_setopt(freq->slot->curl, CURLOPT_URL, freq->url);
diff --git a/list.h b/list.h
new file mode 100644
index 0000000000..a226a870dc
--- /dev/null
+++ b/list.h
@@ -0,0 +1,166 @@
+/*
+ * Copyright (C) 2002 Free Software Foundation, Inc.
+ * (originally part of the GNU C Library and Userspace RCU)
+ * Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
+ *
+ * Copyright (C) 2009 Pierre-Marc Fournier
+ * Conversion to RCU list.
+ * Copyright (C) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef LIST_H
+#define LIST_H	1
+
+/*
+ * The definitions of this file are adopted from those which can be
+ * found in the Linux kernel headers to enable people familiar with the
+ * latter find their way in these sources as well.
+ */
+
+/* Basic type for the double-link list. */
+struct list_head {
+	struct list_head *next, *prev;
+};
+
+/* avoid conflicts with BSD-only sys/queue.h */
+#undef LIST_HEAD
+/* Define a variable with the head and tail of the list. */
+#define LIST_HEAD(name) \
+	struct list_head name = { &(name), &(name) }
+
+/* Initialize a new list head. */
+#define INIT_LIST_HEAD(ptr) \
+	(ptr)->next = (ptr)->prev = (ptr)
+
+#define LIST_HEAD_INIT(name) { &(name), &(name) }
+
+/* Add new element at the head of the list. */
+static inline void list_add(struct list_head *newp, struct list_head *head)
+{
+	head->next->prev = newp;
+	newp->next = head->next;
+	newp->prev = head;
+	head->next = newp;
+}
+
+/* Add new element at the tail of the list. */
+static inline void list_add_tail(struct list_head *newp, struct list_head *head)
+{
+	head->prev->next = newp;
+	newp->next = head;
+	newp->prev = head->prev;
+	head->prev = newp;
+}
+
+/* Remove element from list. */
+static inline void __list_del(struct list_head *prev, struct list_head *next)
+{
+	next->prev = prev;
+	prev->next = next;
+}
+
+/* Remove element from list. */
+static inline void list_del(struct list_head *elem)
+{
+	__list_del(elem->prev, elem->next);
+}
+
+/* Remove element from list, initializing the element's list pointers. */
+static inline void list_del_init(struct list_head *elem)
+{
+	list_del(elem);
+	INIT_LIST_HEAD(elem);
+}
+
+/* Delete from list, add to another list as head. */
+static inline void list_move(struct list_head *elem, struct list_head *head)
+{
+	__list_del(elem->prev, elem->next);
+	list_add(elem, head);
+}
+
+/* Replace an old entry. */
+static inline void list_replace(struct list_head *old, struct list_head *newp)
+{
+	newp->next = old->next;
+	newp->prev = old->prev;
+	newp->prev->next = newp;
+	newp->next->prev = newp;
+}
+
+/* Join two lists. */
+static inline void list_splice(struct list_head *add, struct list_head *head)
+{
+	/* Do nothing if the list which gets added is empty. */
+	if (add != add->next) {
+		add->next->prev = head;
+		add->prev->next = head->next;
+		head->next->prev = add->prev;
+		head->next = add->next;
+	}
+}
+
+/* Get typed element from list at a given position. */
+#define list_entry(ptr, type, member) \
+	((type *) ((char *) (ptr) - offsetof(type, member)))
+
+/* Get first entry from a list. */
+#define list_first_entry(ptr, type, member) \
+	list_entry((ptr)->next, type, member)
+
+/* Iterate forward over the elements of the list. */
+#define list_for_each(pos, head) \
+	for (pos = (head)->next; pos != (head); pos = pos->next)
+
+/*
+ * Iterate forward over the elements list. The list elements can be
+ * removed from the list while doing this.
+ */
+#define list_for_each_safe(pos, p, head) \
+	for (pos = (head)->next, p = pos->next; \
+		pos != (head); \
+		pos = p, p = pos->next)
+
+/* Iterate backward over the elements of the list. */
+#define list_for_each_prev(pos, head) \
+	for (pos = (head)->prev; pos != (head); pos = pos->prev)
+
+/*
+ * Iterate backwards over the elements list. The list elements can be
+ * removed from the list while doing this.
+ */
+#define list_for_each_prev_safe(pos, p, head) \
+	for (pos = (head)->prev, p = pos->prev; \
+		pos != (head); \
+		pos = p, p = pos->prev)
+
+static inline int list_empty(struct list_head *head)
+{
+	return head == head->next;
+}
+
+static inline void list_replace_init(struct list_head *old,
+				     struct list_head *newp)
+{
+	struct list_head *head = old->next;
+
+	list_del(old);
+	list_add_tail(newp, head);
+	INIT_LIST_HEAD(old);
+}
+
+#endif /* LIST_H */