minor code corrections (#1430)

use compact span cast. extend split_path api with only_first_part flag. use single loadlibrary and getprocaddress for IP helper

include/libtorrent/file.hpp

@@ -146,7 +146,8 @@ namespace libtorrent
 	TORRENT_EXTRA_EXPORT void hard_link(std::string const& file
 		, std::string const& link, error_code& ec);
 
-	TORRENT_EXTRA_EXPORT std::string split_path(std::string const& f);
+	TORRENT_EXTRA_EXPORT std::string split_path(std::string const& f
+		, bool only_first_part = false);
 	TORRENT_EXTRA_EXPORT char const* next_path_element(char const* p);
 	TORRENT_EXTRA_EXPORT std::string extension(std::string const& f);
 	TORRENT_EXTRA_EXPORT std::string remove_extension(std::string const& f);

src/disk_io_thread.cpp

@@ -173,6 +173,7 @@ namespace libtorrent
 			if (m_lock) m_lock->lock();
 			m_lock = rhs.m_lock;
 			rhs.m_lock = nullptr;
+			return *this;
 		}
 	private:
 		Lock* m_lock;

src/enum_net.cpp

@@ -385,6 +385,41 @@ namespace libtorrent
 		return false;
 	}
 
+#ifdef TORRENT_WINDOWS
+	struct iphlpapi {
+		static constexpr char const* library_name = "iphlpapi.dll";
+	};
+
+	template <typename Library>
+	HMODULE get_library_handle()
+	{
+		static bool handle_checked = false;
+		static HMODULE handle = 0;
+
+		if (!handle_checked)
+		{
+			handle = LoadLibraryA(Library::library_name);
+			handle_checked = true;
+		}
+		return handle;
+	}
+
+	template <typename Library, typename Signature>
+	Signature get_library_procedure(LPCSTR name)
+	{
+		static Signature proc = nullptr;
+		static bool failed_proc = false;
+
+		if ((proc == nullptr) && !failed_proc)
+		{
+			HMODULE const handle = get_library_handle<Library>();
+			if (handle) proc = (Signature)GetProcAddress(handle, name);
+			failed_proc = (proc == nullptr);
+		}
+		return proc;
+	}
+#endif
+
 #if TORRENT_USE_GETIPFORWARDTABLE
 	address build_netmask(int bits, int family)
 	{
@@ -590,22 +625,13 @@ namespace libtorrent
 #elif TORRENT_USE_GETADAPTERSADDRESSES
 
 #if _WIN32_WINNT >= 0x0501
-		// Load Iphlpapi library
+		typedef ULONG (WINAPI *GetAdaptersAddresses_t)(ULONG,ULONG,PVOID,PIP_ADAPTER_ADDRESSES,PULONG);
-		HMODULE iphlp = LoadLibraryA("Iphlpapi.dll");
+		// Get GetAdaptersAddresses() pointer
-		if (iphlp)
+		auto GetAdaptersAddresses =
+			get_library_procedure<iphlpapi, GetAdaptersAddresses_t>("GetAdaptersAddresses");
+
+		if (GetAdaptersAddresses != nullptr)
 		{
-			// Get GetAdaptersAddresses() pointer
-			typedef ULONG (WINAPI *GetAdaptersAddresses_t)(ULONG,ULONG,PVOID,PIP_ADAPTER_ADDRESSES,PULONG);
-			GetAdaptersAddresses_t GetAdaptersAddresses = (GetAdaptersAddresses_t)GetProcAddress(
-				iphlp, "GetAdaptersAddresses");
-
-			if (GetAdaptersAddresses == nullptr)
-			{
-				FreeLibrary(iphlp);
-				ec = error_code(boost::system::errc::not_supported, generic_category());
-				return std::vector<ip_interface>();
-			}
-
 			ULONG buf_size = 10000;
 			std::vector<char> buffer(buf_size);
 			PIP_ADAPTER_ADDRESSES adapter_addresses
@@ -622,7 +648,6 @@ namespace libtorrent
 			}
 			if (res != NO_ERROR)
 			{
-				FreeLibrary(iphlp);
 				ec = error_code(WSAGetLastError(), system_category());
 				return std::vector<ip_interface>();
 			}
@@ -645,8 +670,6 @@ namespace libtorrent
 				}
 			}
 
-			// Free memory
-			FreeLibrary(iphlp);
 			return ret;
 		}
 #endif
@@ -915,20 +938,11 @@ namespace libtorrent
 #elif TORRENT_USE_GETIPFORWARDTABLE
 /*
 	move this to enum_net_interfaces
-		// Load Iphlpapi library
-		HMODULE iphlp = LoadLibraryA("Iphlpapi.dll");
-		if (!iphlp)
-		{
-			ec = boost::asio::error::operation_not_supported;
-			return std::vector<ip_route>();
-		}
-
 		// Get GetAdaptersInfo() pointer
 		typedef DWORD (WINAPI *GetAdaptersInfo_t)(PIP_ADAPTER_INFO, PULONG);
-		GetAdaptersInfo_t GetAdaptersInfo = (GetAdaptersInfo_t)GetProcAddress(iphlp, "GetAdaptersInfo");
+		GetAdaptersInfo_t GetAdaptersInfo = get_library_procedure<iphlpapi, GetAdaptersInfo_t>("GetAdaptersInfo");
-		if (!GetAdaptersInfo)
+		if (GetAdaptersInfo == nullptr)
 		{
-			FreeLibrary(iphlp);
 			ec = boost::asio::error::operation_not_supported;
 			return std::vector<ip_route>();
 		}
@@ -937,7 +951,6 @@ namespace libtorrent
 		ULONG out_buf_size = 0;
 		if (GetAdaptersInfo(adapter_info, &out_buf_size) != ERROR_BUFFER_OVERFLOW)
 		{
-			FreeLibrary(iphlp);
 			ec = boost::asio::error::operation_not_supported;
 			return std::vector<ip_route>();
 		}
@@ -945,7 +958,6 @@ namespace libtorrent
 		adapter_info = (IP_ADAPTER_INFO*)malloc(out_buf_size);
 		if (!adapter_info)
 		{
-			FreeLibrary(iphlp);
 			ec = boost::asio::error::no_memory;
 			return std::vector<ip_route>();
 		}
@@ -973,20 +985,12 @@ namespace libtorrent
 
 		// Free memory
 		free(adapter_info);
-		FreeLibrary(iphlp);
 */
 
-		// Load Iphlpapi library
-		HMODULE iphlp = LoadLibraryA("Iphlpapi.dll");
-		if (!iphlp)
-		{
-			ec = boost::asio::error::operation_not_supported;
-			return std::vector<ip_route>();
-		}
-
 		typedef DWORD (WINAPI *GetIfEntry_t)(PMIB_IFROW pIfRow);
-		GetIfEntry_t GetIfEntry = (GetIfEntry_t)GetProcAddress(iphlp, "GetIfEntry");
+		auto GetIfEntry = get_library_procedure<iphlpapi, GetIfEntry_t>("GetIfEntry");
-		if (!GetIfEntry)
+
+		if (GetIfEntry == nullptr)
 		{
 			ec = boost::asio::error::operation_not_supported;
 			return std::vector<ip_route>();
@@ -997,11 +1001,9 @@ namespace libtorrent
 			ADDRESS_FAMILY, PMIB_IPFORWARD_TABLE2*);
 		typedef void (WINAPI *FreeMibTable_t)(PVOID Memory);
 
-		GetIpForwardTable2_t GetIpForwardTable2 = (GetIpForwardTable2_t)GetProcAddress(
+		auto GetIpForwardTable2 = get_library_procedure<iphlpapi, GetIpForwardTable2_t>("GetIpForwardTable2");
-			iphlp, "GetIpForwardTable2");
+		auto FreeMibTable = get_library_procedure<iphlpapi, FreeMibTable_t>("FreeMibTable");
-		FreeMibTable_t FreeMibTable = (FreeMibTable_t)GetProcAddress(
+		if (GetIpForwardTable2 != nullptr && FreeMibTable != nullptr)
-			iphlp, "FreeMibTable");
-		if (GetIpForwardTable2 && FreeMibTable)
 		{
 			MIB_IPFORWARD_TABLE2* routes = nullptr;
 			int res = GetIpForwardTable2(AF_UNSPEC, &routes);
@@ -1026,7 +1028,6 @@ namespace libtorrent
 				}
 			}
 			if (routes) FreeMibTable(routes);
-			FreeLibrary(iphlp);
 			return ret;
 		}
 #endif
@@ -1034,11 +1035,9 @@ namespace libtorrent
 		// Get GetIpForwardTable() pointer
 		typedef DWORD (WINAPI *GetIpForwardTable_t)(PMIB_IPFORWARDTABLE pIpForwardTable,PULONG pdwSize,BOOL bOrder);
 
-		GetIpForwardTable_t GetIpForwardTable = (GetIpForwardTable_t)GetProcAddress(
+		auto GetIpForwardTable = get_library_procedure<iphlpapi, GetIpForwardTable_t>("GetIpForwardTable");
-			iphlp, "GetIpForwardTable");
+		if (GetIpForwardTable == nullptr)
-		if (!GetIpForwardTable)
 		{
-			FreeLibrary(iphlp);
 			ec = boost::asio::error::operation_not_supported;
 			return std::vector<ip_route>();
 		}
@@ -1047,7 +1046,6 @@ namespace libtorrent
 		ULONG out_buf_size = 0;
 		if (GetIpForwardTable(routes, &out_buf_size, FALSE) != ERROR_INSUFFICIENT_BUFFER)
 		{
-			FreeLibrary(iphlp);
 			ec = boost::asio::error::operation_not_supported;
 			return std::vector<ip_route>();
 		}
@@ -1055,7 +1053,6 @@ namespace libtorrent
 		routes = (MIB_IPFORWARDTABLE*)malloc(out_buf_size);
 		if (!routes)
 		{
-			FreeLibrary(iphlp);
 			ec = boost::asio::error::no_memory;
 			return std::vector<ip_route>();
 		}
@@ -1082,7 +1079,6 @@ namespace libtorrent
 
 		// Free memory
 		free(routes);
-		FreeLibrary(iphlp);
 #elif TORRENT_USE_NETLINK
 		enum { BUFSIZE = 8192 };
 

src/file.cpp

@@ -720,7 +720,7 @@ namespace libtorrent
 		}
 	}
 
-	std::string split_path(std::string const& f)
+	std::string split_path(std::string const& f, bool only_first_part)
 	{
 		if (f.empty()) return f;
 
@@ -738,11 +738,13 @@ namespace libtorrent
 			if (p - start > 0)
 			{
 				ret.append(start, p - start);
+				if (only_first_part) return ret;
 				ret.append(1, '\0');
 			}
 			if (*p != 0) ++p;
 			start = p;
 		}
+		if (only_first_part) return ret;
 		ret.append(1, '\0');
 		return ret;
 	}

src/file_storage.cpp

@@ -563,7 +563,7 @@ namespace libtorrent
 		else
 		{
 			if (m_files.empty())
-				m_name = split_path(path).c_str();
+				m_name = split_path(path, true);
 		}
 
 		// this is poor-man's emplace_back()

src/storage.cpp

@@ -834,8 +834,9 @@ namespace libtorrent
 		, storage_error& ec)
 	{
 		file_storage const& fs = files();
-
+#ifdef TORRENT_DISABLE_MUTABLE_TORRENTS
-#ifndef TORRENT_DISABLE_MUTABLE_TORRENTS
+		TORRENT_UNUSED(links);
+#else
 		if (!links.empty())
 		{
 			TORRENT_ASSERT(int(links.size()) == fs.num_files());

src/utp_socket_manager.cpp

@@ -161,7 +161,7 @@ namespace libtorrent
 	{
 //		UTP_LOGV("incoming packet size:%d\n", size);
 
-		if (p.size() < int(sizeof(utp_header))) return false;
+		if (p.size() < sizeof(utp_header)) return false;
 
 		utp_header const* ph = reinterpret_cast<utp_header const*>(p.data());
 

src/utp_stream.cpp

@@ -712,8 +712,7 @@ bool utp_incoming_packet(utp_socket_impl* s
 	, span<char const> p
 	, udp::endpoint const& ep, time_point receive_time)
 {
-	return s->incoming_packet(
+	return s->incoming_packet({reinterpret_cast<std::uint8_t const*>(p.data()), p.size()}
-		span<std::uint8_t const>(reinterpret_cast<std::uint8_t const*>(p.data()), int(p.size()))
 		, ep, receive_time);
 }