1 files changed, 586 insertions, 0 deletions

diff --git a/http-walker.c b/http-walker.c
new file mode 100644
index 0000000000..88da5468e7
--- /dev/null
+++ b/http-walker.c
@@ -0,0 +1,586 @@
+#include "cache.h"
+#include "commit.h"
+#include "walker.h"
+#include "http.h"
+
+struct alt_base {
+	char *base;
+	int got_indices;
+	struct packed_git *packs;
+	struct alt_base *next;
+};
+
+enum object_request_state {
+	WAITING,
+	ABORTED,
+	ACTIVE,
+	COMPLETE
+};
+
+struct object_request {
+	struct walker *walker;
+	unsigned char sha1[20];
+	struct alt_base *repo;
+	enum object_request_state state;
+	struct http_object_request *req;
+	struct object_request *next;
+};
+
+struct alternates_request {
+	struct walker *walker;
+	const char *base;
+	char *url;
+	struct strbuf *buffer;
+	struct active_request_slot *slot;
+	int http_specific;
+};
+
+struct walker_data {
+	const char *url;
+	int got_alternates;
+	struct alt_base *alt;
+};
+
+static struct object_request *object_queue_head;
+
+static void fetch_alternates(struct walker *walker, const char *base);
+
+static void process_object_response(void *callback_data);
+
+static void start_object_request(struct walker *walker,
+				 struct object_request *obj_req)
+{
+	struct active_request_slot *slot;
+	struct http_object_request *req;
+
+	req = new_http_object_request(obj_req->repo->base, obj_req->sha1);
+	if (req == NULL) {
+		obj_req->state = ABORTED;
+		return;
+	}
+	obj_req->req = req;
+
+	slot = req->slot;
+	slot->callback_func = process_object_response;
+	slot->callback_data = obj_req;
+
+	/* Try to get the request started, abort the request on error */
+	obj_req->state = ACTIVE;
+	if (!start_active_slot(slot)) {
+		obj_req->state = ABORTED;
+		release_http_object_request(req);
+		return;
+	}
+}
+
+static void finish_object_request(struct object_request *obj_req)
+{
+	if (finish_http_object_request(obj_req->req))
+		return;
+
+	if (obj_req->req->rename == 0)
+		walker_say(obj_req->walker, "got %s\n", sha1_to_hex(obj_req->sha1));
+}
+
+static void process_object_response(void *callback_data)
+{
+	struct object_request *obj_req =
+		(struct object_request *)callback_data;
+	struct walker *walker = obj_req->walker;
+	struct walker_data *data = walker->data;
+	struct alt_base *alt = data->alt;
+
+	process_http_object_request(obj_req->req);
+	obj_req->state = COMPLETE;
+
+	/* Use alternates if necessary */
+	if (missing_target(obj_req->req)) {
+		fetch_alternates(walker, alt->base);
+		if (obj_req->repo->next != NULL) {
+			obj_req->repo =
+				obj_req->repo->next;
+			release_http_object_request(obj_req->req);
+			start_object_request(walker, obj_req);
+			return;
+		}
+	}
+
+	finish_object_request(obj_req);
+}
+
+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;
+	}
+
+	free(obj_req);
+}
+
+#ifdef USE_CURL_MULTI
+static int fill_active_slot(struct walker *walker)
+{
+	struct object_request *obj_req;
+
+	for (obj_req = object_queue_head; obj_req; obj_req = obj_req->next) {
+		if (obj_req->state == WAITING) {
+			if (has_sha1_file(obj_req->sha1))
+				obj_req->state = COMPLETE;
+			else {
+				start_object_request(walker, obj_req);
+				return 1;
+			}
+		}
+	}
+	return 0;
+}
+#endif
+
+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));
+	newreq->walker = walker;
+	hashcpy(newreq->sha1, 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;
+	}
+
+#ifdef USE_CURL_MULTI
+	fill_active_slots();
+	step_active_slots();
+#endif
+}
+
+static void process_alternates_response(void *callback_data)
+{
+	struct alternates_request *alt_req =
+		(struct alternates_request *)callback_data;
+	struct walker *walker = alt_req->walker;
+	struct walker_data *cdata = walker->data;
+	struct active_request_slot *slot = alt_req->slot;
+	struct alt_base *tail = cdata->alt;
+	const char *base = alt_req->base;
+	const char null_byte = '\0';
+	char *data;
+	int i = 0;
+
+	if (alt_req->http_specific) {
+		if (slot->curl_result != CURLE_OK ||
+		    !alt_req->buffer->len) {
+
+			/* 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;
+			if (slot->finished != NULL)
+				(*slot->finished) = 0;
+			if (!start_active_slot(slot)) {
+				cdata->got_alternates = -1;
+				slot->in_use = 0;
+				if (slot->finished != NULL)
+					(*slot->finished) = 1;
+			}
+			return;
+		}
+	} else if (slot->curl_result != CURLE_OK) {
+		if (!missing_target(slot)) {
+			cdata->got_alternates = -1;
+			return;
+		}
+	}
+
+	fwrite_buffer((char *)&null_byte, 1, 1, alt_req->buffer);
+	alt_req->buffer->len--;
+	data = alt_req->buffer->buf;
+
+	while (i < alt_req->buffer->len) {
+		int posn = i;
+		while (posn < alt_req->buffer->len && data[posn] != '\n')
+			posn++;
+		if (data[posn] == '\n') {
+			int okay = 0;
+			int serverlen = 0;
+			struct alt_base *newalt;
+			if (data[i] == '/') {
+				/*
+				 * This counts
+				 * http://git.host/pub/scm/linux.git/
+				 * -----------here^
+				 * so memcpy(dst, base, serverlen) will
+				 * copy up to "...git.host".
+				 */
+				const char *colon_ss = strstr(base,"://");
+				if (colon_ss) {
+					serverlen = (strchr(colon_ss + 3, '/')
+						     - base);
+					okay = 1;
+				}
+			} else if (!memcmp(data + i, "../", 3)) {
+				/*
+				 * Relative URL; chop the corresponding
+				 * number of subpath from base (and ../
+				 * from data), and concatenate the result.
+				 *
+				 * The code first drops ../ from data, and
+				 * then drops one ../ from data and one path
+				 * from base.  IOW, one extra ../ is dropped
+				 * from data than path is dropped from base.
+				 *
+				 * This is not wrong.  The alternate in
+				 *     http://git.host/pub/scm/linux.git/
+				 * to borrow from
+				 *     http://git.host/pub/scm/linus.git/
+				 * is ../../linus.git/objects/.  You need
+				 * two ../../ to borrow from your direct
+				 * neighbour.
+				 */
+				i += 3;
+				serverlen = strlen(base);
+				while (i + 2 < posn &&
+				       !memcmp(data + i, "../", 3)) {
+					do {
+						serverlen--;
+					} while (serverlen &&
+						 base[serverlen - 1] != '/');
+					i += 3;
+				}
+				/* If the server got removed, give up. */
+				okay = strchr(base, ':') - base + 3 <
+				       serverlen;
+			} else if (alt_req->http_specific) {
+				char *colon = strchr(data + i, ':');
+				char *slash = strchr(data + i, '/');
+				if (colon && slash && colon < data + posn &&
+				    slash < data + posn && colon < slash) {
+					okay = 1;
+				}
+			}
+			/* skip "objects\n" at end */
+			if (okay) {
+				struct strbuf target = STRBUF_INIT;
+				strbuf_add(&target, base, serverlen);
+				strbuf_add(&target, data + i, posn - i - 7);
+				if (walker->get_verbosely)
+					fprintf(stderr, "Also look at %s\n",
+						target.buf);
+				newalt = xmalloc(sizeof(*newalt));
+				newalt->next = NULL;
+				newalt->base = strbuf_detach(&target, NULL);
+				newalt->got_indices = 0;
+				newalt->packs = NULL;
+
+				while (tail->next != NULL)
+					tail = tail->next;
+				tail->next = newalt;
+			}
+		}
+		i = posn + 1;
+	}
+
+	cdata->got_alternates = 1;
+}
+
+static void fetch_alternates(struct walker *walker, const char *base)
+{
+	struct strbuf buffer = STRBUF_INIT;
+	char *url;
+	struct active_request_slot *slot;
+	struct alternates_request alt_req;
+	struct walker_data *cdata = walker->data;
+
+	/*
+	 * If another request has already started fetching alternates,
+	 * wait for them to arrive and return to processing this request's
+	 * curl message
+	 */
+#ifdef USE_CURL_MULTI
+	while (cdata->got_alternates == 0) {
+		step_active_slots();
+	}
+#endif
+
+	/* Nothing to do if they've already been fetched */
+	if (cdata->got_alternates == 1)
+		return;
+
+	/* Start the fetch */
+	cdata->got_alternates = 0;
+
+	if (walker->get_verbosely)
+		fprintf(stderr, "Getting alternates list for %s\n", base);
+
+	url = xstrfmt("%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_response;
+	alt_req.walker = walker;
+	slot->callback_data = &alt_req;
+
+	curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
+	curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
+	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
+		cdata->got_alternates = -1;
+
+	strbuf_release(&buffer);
+	free(url);
+}
+
+static int fetch_indices(struct walker *walker, struct alt_base *repo)
+{
+	int ret;
+
+	if (repo->got_indices)
+		return 0;
+
+	if (walker->get_verbosely)
+		fprintf(stderr, "Getting pack list for %s\n", repo->base);
+
+	switch (http_get_info_packs(repo->base, &repo->packs)) {
+	case HTTP_OK:
+	case HTTP_MISSING_TARGET:
+		repo->got_indices = 1;
+		ret = 0;
+		break;
+	default:
+		repo->got_indices = 0;
+		ret = -1;
+	}
+
+	return ret;
+}
+
+static int http_fetch_pack(struct walker *walker, struct alt_base *repo, unsigned char *sha1)
+{
+	struct packed_git *target;
+	int ret;
+	struct slot_results results;
+	struct http_pack_request *preq;
+
+	if (fetch_indices(walker, repo))
+		return -1;
+	target = find_sha1_pack(sha1, repo->packs);
+	if (!target)
+		return -1;
+
+	if (walker->get_verbosely) {
+		fprintf(stderr, "Getting pack %s\n",
+			sha1_to_hex(target->sha1));
+		fprintf(stderr, " which contains %s\n",
+			sha1_to_hex(sha1));
+	}
+
+	preq = new_http_pack_request(target, repo->base);
+	if (preq == NULL)
+		goto abort;
+	preq->lst = &repo->packs;
+	preq->slot->results = &results;
+
+	if (start_active_slot(preq->slot)) {
+		run_active_slot(preq->slot);
+		if (results.curl_result != CURLE_OK) {
+			error("Unable to get pack file %s\n%s", preq->url,
+			      curl_errorstr);
+			goto abort;
+		}
+	} else {
+		error("Unable to start request");
+		goto abort;
+	}
+
+	ret = finish_http_pack_request(preq);
+	release_http_pack_request(preq);
+	if (ret)
+		return ret;
+
+	return 0;
+
+abort:
+	return -1;
+}
+
+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)
+{
+	char *hex = sha1_to_hex(sha1);
+	int ret = 0;
+	struct object_request *obj_req = object_queue_head;
+	struct http_object_request *req;
+
+	while (obj_req != NULL && hashcmp(obj_req->sha1, sha1))
+		obj_req = obj_req->next;
+	if (obj_req == NULL)
+		return error("Couldn't find request for %s in the queue", hex);
+
+	if (has_sha1_file(obj_req->sha1)) {
+		if (obj_req->req != NULL)
+			abort_http_object_request(obj_req->req);
+		abort_object_request(obj_req);
+		return 0;
+	}
+
+#ifdef USE_CURL_MULTI
+	while (obj_req->state == WAITING)
+		step_active_slots();
+#else
+	start_object_request(walker, obj_req);
+#endif
+
+	/*
+	 * obj_req->req might change when fetching alternates in the callback
+	 * process_object_response; therefore, the "shortcut" variable, req,
+	 * is used only after we're done with slots.
+	 */
+	while (obj_req->state == ACTIVE)
+		run_active_slot(obj_req->req->slot);
+
+	req = obj_req->req;
+
+	if (req->localfile != -1) {
+		close(req->localfile);
+		req->localfile = -1;
+	}
+
+	if (obj_req->state == ABORTED) {
+		ret = error("Request for %s aborted", hex);
+	} else if (req->curl_result != CURLE_OK &&
+		   req->http_code != 416) {
+		if (missing_target(req))
+			ret = -1; /* Be silent, it is probably in a pack. */
+		else
+			ret = error("%s (curl_result = %d, http_code = %ld, sha1 = %s)",
+				    req->errorstr, req->curl_result,
+				    req->http_code, hex);
+	} else if (req->zret != Z_STREAM_END) {
+		walker->corrupt_object_found++;
+		ret = error("File %s (%s) corrupt", hex, req->url);
+	} else if (hashcmp(obj_req->sha1, req->real_sha1)) {
+		ret = error("File %s has bad hash", hex);
+	} else if (req->rename < 0) {
+		ret = error("unable to write sha1 filename %s",
+			    sha1_file_name(req->sha1));
+	}
+
+	release_http_object_request(req);
+	release_object_request(obj_req);
+	return ret;
+}
+
+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))
+		return 0;
+	while (altbase) {
+		if (!http_fetch_pack(walker, altbase, sha1))
+			return 0;
+		fetch_alternates(walker, data->alt->base);
+		altbase = altbase->next;
+	}
+	return error("Unable to find %s under %s", sha1_to_hex(sha1),
+		     data->alt->base);
+}
+
+static int fetch_ref(struct walker *walker, struct ref *ref)
+{
+	struct walker_data *data = walker->data;
+	return http_fetch_ref(data->alt->base, ref);
+}
+
+static void cleanup(struct walker *walker)
+{
+	struct walker_data *data = walker->data;
+	struct alt_base *alt, *alt_next;
+
+	if (data) {
+		alt = data->alt;
+		while (alt) {
+			alt_next = alt->next;
+
+			free(alt->base);
+			free(alt);
+
+			alt = alt_next;
+		}
+		free(data);
+		walker->data = NULL;
+	}
+}
+
+struct walker *get_http_walker(const char *url)
+{
+	char *s;
+	struct walker_data *data = xmalloc(sizeof(struct walker_data));
+	struct walker *walker = xmalloc(sizeof(struct walker));
+
+	data->alt = xmalloc(sizeof(*data->alt));
+	data->alt->base = xstrdup(url);
+	for (s = data->alt->base + strlen(data->alt->base) - 1; *s == '/'; --s)
+		*s = 0;
+
+	data->alt->got_indices = 0;
+	data->alt->packs = NULL;
+	data->alt->next = NULL;
+	data->got_alternates = -1;
+
+	walker->corrupt_object_found = 0;
+	walker->fetch = fetch;
+	walker->fetch_ref = fetch_ref;
+	walker->prefetch = prefetch;
+	walker->cleanup = cleanup;
+	walker->data = data;
+
+#ifdef USE_CURL_MULTI
+	add_fill_function(walker, (int (*)(void *)) fill_active_slot);
+#endif
+
+	return walker;
+}