Prevent duplicate url (#1231)

prevent creating torrents with duplicate trackers as well as adding duplicate trackers to torrent_info

src/create_torrent.cpp

@@ -664,6 +664,9 @@ namespace libtorrent
 
 	void create_torrent::add_tracker(string_view url, int const tier)
 	{
+		auto i = std::find_if(m_urls.begin(), m_urls.end()
+			, [&url](announce_entry const& ae) { return ae.first == url.to_string(); });
+		if (i != m_urls.end()) return;
 		m_urls.push_back(announce_entry(url.to_string(), tier));
 
 		std::sort(m_urls.begin(), m_urls.end()

src/torrent_info.cpp

@@ -1347,6 +1347,7 @@ namespace libtorrent
 				if (ec) return false;
 
 				m_info_hash = p.info_hash;
+				m_urls.reserve(m_urls.size() + p.trackers.size());
 				for (auto const& url : p.trackers)
 					m_urls.push_back(announce_entry(url));
 
@@ -1534,6 +1535,10 @@ namespace libtorrent
 
 	void torrent_info::add_tracker(std::string const& url, int tier)
 	{
+		auto i = std::find_if(m_urls.begin(), m_urls.end()
+			, [&url](announce_entry const& ae) { return ae.url == url; });
+		if (i != m_urls.end()) return;
+
 		announce_entry e(url);
 		e.tier = tier;
 		e.source = announce_entry::source_client;

test/test_create_torrent.cpp

@@ -36,6 +36,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/create_torrent.hpp"
 #include "libtorrent/bencode.hpp"
 #include "libtorrent/aux_/escape_string.hpp" // for convert_path_to_posix
+#include "libtorrent/announce_entry.hpp"
 
 #include <cstring>
 
@@ -49,6 +50,10 @@ TORRENT_TEST(create_verbatim_torrent)
 
 	lt::torrent_info info(test_torrent, sizeof(test_torrent) - 1);
 
+	info.add_tracker("http://test.com");
+	info.add_tracker("http://test.com");
+	TEST_EQUAL(info.trackers().size(), 1);
+	
 	lt::create_torrent t(info);
 
 	std::vector<char> buffer;