From 77c0fa5872db38084e806bafe4abce1857985bd5 Mon Sep 17 00:00:00 2001
From: Arvid Norberg <arvid@libtorrent.org>
Date: Mon, 1 Mar 2010 06:46:57 +0000
Subject: [PATCH] support multiple trackers in magnet links

---
 ChangeLog                            |  1 +
 include/libtorrent/escape_string.hpp |  2 +-
 src/escape_string.cpp                |  4 +++-
 src/magnet_uri.cpp                   | 18 +++++++++++++--
 test/test_primitives.cpp             | 33 +++++++++++++++++++++++++++-
 5 files changed, 53 insertions(+), 5 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 70c415bbc..2426970fc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -19,6 +19,7 @@
 
 0.15 release
 
+	* added support for multiple trackers in magnet links
 	* added support for explicitly flushing the disk cache
 	* added torrent priority to affect bandwidth allocation for its peers
 	* reduced the number of floating point operations (to better support
diff --git a/include/libtorrent/escape_string.hpp b/include/libtorrent/escape_string.hpp
index 042626ce0..439be40e5 100644
--- a/include/libtorrent/escape_string.hpp
+++ b/include/libtorrent/escape_string.hpp
@@ -72,7 +72,7 @@ namespace libtorrent
 	TORRENT_EXPORT std::string base32decode(std::string const& s);
 
 	TORRENT_EXPORT std::string url_has_argument(
-		std::string const& url, std::string argument);
+		std::string const& url, std::string argument, int* out_pos = 0);
 
 	// replaces \ with /
 	TORRENT_EXPORT void convert_path_to_posix(std::string& path);
diff --git a/src/escape_string.cpp b/src/escape_string.cpp
index aae8c4349..49338f507 100644
--- a/src/escape_string.cpp
+++ b/src/escape_string.cpp
@@ -473,7 +473,7 @@ namespace libtorrent
 	}
 
 	std::string url_has_argument(
-		std::string const& url, std::string argument)
+		std::string const& url, std::string argument, int* out_pos)
 	{
 		size_t i = url.find('?');
 		if (i == std::string::npos) return std::string();
@@ -484,12 +484,14 @@ namespace libtorrent
 		if (url.compare(i, argument.size(), argument) == 0)
 		{
 			size_t pos = i + argument.size();
+			if (out_pos) *out_pos = pos;
 			return url.substr(pos, url.find('&', pos) - pos);
 		}
 		argument.insert(0, "&");
 		i = url.find(argument, i);
 		if (i == std::string::npos) return std::string();
 		size_t pos = i + argument.size();
+		if (out_pos) *out_pos = pos;
 		return url.substr(pos, url.find('&', pos) - pos);
 	}
 
diff --git a/src/magnet_uri.cpp b/src/magnet_uri.cpp
index 793e03ef3..81982ca63 100644
--- a/src/magnet_uri.cpp
+++ b/src/magnet_uri.cpp
@@ -146,7 +146,8 @@ namespace libtorrent
 		error_code e;
 		std::string display_name = url_has_argument(uri, "dn");
 		if (!display_name.empty()) name = unescape_string(display_name.c_str(), e);
-		std::string tracker_string = url_has_argument(uri, "tr");
+		int pos = std::string::npos;
+		std::string tracker_string = url_has_argument(uri, "tr", &pos);
 		if (!tracker_string.empty()) tracker = unescape_string(tracker_string.c_str(), e);
 	
 		std::string btih = url_has_argument(uri, "xt");
@@ -169,7 +170,20 @@ namespace libtorrent
 		if (!tracker.empty()) p.tracker_url = tracker.c_str();
 		p.info_hash = info_hash;
 		if (!name.empty()) p.name = name.c_str();
-		return ses.add_torrent(p, ec);
+		torrent_handle ret = ses.add_torrent(p, ec);
+
+		int tier = 1;
+		// there might be more trackers in the url
+		while (pos != std::string::npos)
+		{
+			pos = uri.find("&tr=", pos);
+			if (pos == std::string::npos) break;
+			pos += 4;
+			announce_entry ae(uri.substr(pos, uri.find('&', pos) - pos));
+			ae.tier = tier++;
+			ret.add_tracker(ae);
+		}
+		return ret;
 	}
 }
 
diff --git a/test/test_primitives.cpp b/test/test_primitives.cpp
index 73fa9d71e..a7d197469 100644
--- a/test/test_primitives.cpp
+++ b/test/test_primitives.cpp
@@ -30,6 +30,7 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/magnet_uri.hpp"
 #include "libtorrent/parse_url.hpp"
 #include "libtorrent/http_tracker_connection.hpp"
 #include "libtorrent/buffer.hpp"
@@ -419,7 +420,37 @@ int test_main()
 */
 	entry session_state;
 	s->save_state(session_state);
-	
+
+	// test magnet link parsing
+	add_torrent_params p;
+	p.save_path = ".";
+	error_code ec;
+	const char* magnet_uri = "magnet:?xt=urn:btih:cdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcd"
+		"&tr=http://1&tr=http://2&tr=http://3&dn=foo";
+	torrent_handle t = add_magnet_uri(*s, magnet_uri, p, ec);
+	TEST_CHECK(!ec);
+	if (ec) fprintf(stderr, "%s\n", ec.message().c_str());
+
+	std::vector<announce_entry> trackers = t.trackers();
+	TEST_EQUAL(trackers.size(), 3);
+	if (trackers.size() > 0)
+	{
+		TEST_EQUAL(trackers[0].url, "http://1");
+		fprintf(stderr, "1: %s\n", trackers[0].url.c_str());
+	}
+	if (trackers.size() > 1)
+	{
+		TEST_EQUAL(trackers[1].url, "http://2");
+		fprintf(stderr, "2: %s\n", trackers[1].url.c_str());
+	}
+	if (trackers.size() > 2)
+	{
+		TEST_EQUAL(trackers[2].url, "http://3");
+		fprintf(stderr, "3: %s\n", trackers[2].url.c_str());
+	}
+
+	TEST_EQUAL(to_hex(t.info_hash().to_string()), "cdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcd");
+
 	delete s;
 	s = new session(fingerprint("LT",0,0,0,0), 0);