clean up use of getrlimit() by wrapping it and move it to platform_util.cpp. Also take the opportunity to make it simulator friendly (consistent in simulation)

include/libtorrent/platform_util.hpp

@@ -5,6 +5,8 @@
 
 namespace libtorrent
 {
+	int max_open_files();
+
 	boost::uint64_t total_physical_ram();
 }
 

src/disk_buffer_pool.cpp

@@ -56,25 +56,6 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <sys/sysctl.h>
 #endif
 
-#if TORRENT_USE_RLIMIT
-
-#ifdef __GNUC__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wlong-long"
-#endif // __GNUC__
-
-#include <sys/resource.h>
-
-// capture this here where warnings are disabled (the macro generates warnings)
-const rlim_t rlimit_as = RLIMIT_AS;
-const rlim_t rlim_infinity = RLIM_INFINITY;
-
-#ifdef __GNUC__
-#pragma GCC diagnostic pop
-#endif // __GNUC__
-
-#endif // TORRENT_USE_RLIMIT
-
 #ifdef TORRENT_LINUX
 #include <linux/unistd.h>
 #endif

src/disk_io_thread.cpp

@@ -40,6 +40,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/error.hpp"
 #include "libtorrent/file_pool.hpp"
 #include "libtorrent/torrent_info.hpp"
+#include "libtorrent/platform_util.hpp"
 #include <boost/scoped_array.hpp>
 #include <boost/bind.hpp>
 #include <boost/tuple/tuple.hpp>
@@ -174,21 +175,14 @@ namespace libtorrent
 		m_disk_cache.set_settings(m_settings, ec);
 		TORRENT_ASSERT(!ec);
 
-#if TORRENT_USE_RLIMIT
-		// ---- auto-cap open files ----
-
-		struct rlimit rl;
-		if (getrlimit(RLIMIT_NOFILE, &rl) == 0)
-		{
-			// deduct some margin for epoll/kqueue, log files,
-			// futexes, shared objects etc.
-			rl.rlim_cur -= 20;
-
-			// 80% of the available file descriptors should go to connections
-			// 20% goes towards regular files
-			m_file_pool.resize((std::min)(m_file_pool.size_limit(), int(rl.rlim_cur * 2 / 10)));
-		}
-#endif // TORRENT_USE_RLIMIT
+		// deduct some margin for epoll/kqueue, log files,
+		// futexes, shared objects etc.
+		// 80% of the available file descriptors should go to connections
+		// 20% goes towards regular files
+		const int max_files = (std::min)((std::max)(5
+				, (max_open_files() - 20) * 2 / 10)
+			, m_file_pool.size_limit());
+		m_file_pool.resize(max_files);
 	}
 
 	disk_io_thread::~disk_io_thread()
@@ -387,7 +381,7 @@ namespace libtorrent
 		// they are ready to be flushed. If so, flush them all,
 		// otherwise, hold off
 		bool range_full = true;
-		
+
 		cached_piece_entry* first_piece = NULL;
 		DLOG("try_flush_hashed: multi-piece: ");
 		for (int i = range_start; i < range_end; ++i)

src/platform_util.cpp

@@ -36,6 +36,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/aux_/disable_warnings_push.hpp"
 
 #include <boost/cstdint.hpp>
+#include <limits>
 
 #if TORRENT_USE_RLIMIT
 
@@ -48,6 +49,7 @@ POSSIBILITY OF SUCH DAMAGE.
 
 // capture this here where warnings are disabled (the macro generates warnings)
 const rlim_t rlimit_as = RLIMIT_AS;
+const rlim_t rlimit_nofile = RLIMIT_NOFILE;
 const rlim_t rlim_infinity = RLIM_INFINITY;
 
 #ifdef __GNUC__
@@ -70,8 +72,33 @@ const rlim_t rlim_infinity = RLIM_INFINITY;
 namespace libtorrent
 {
 
+	int max_open_files()
+	{
+#if defined TORRENT_BUILD_SIMULATOR
+		return 256;
+#elif TORRENT_USE_RLIMIT
+
+		struct rlimit rl;
+		if (getrlimit(RLIMIT_NOFILE, &rl) == 0)
+		{
+			if (rl.rlim_cur == rlim_infinity)
+				return (std::numeric_limits<int>::max)();
+
+			return rl.rlim_cur;
+		}
+		return 1024;
+#else
+		// this seems like a reasonable limit for windows.
+		// http://blogs.msdn.com/b/oldnewthing/archive/2007/07/18/3926581.aspx
+		return 10000;
+#endif
+	}
+
 	boost::uint64_t total_physical_ram()
 	{
+#if defined TORRENT_BUILD_SIMULATOR
+		return boost::uint64_t(4) * 1024 * 1024 * 1024;
+#else
 		// figure out how much physical RAM there is in
 		// this machine. This is used for automatically
 		// sizing the disk cache size when it's set to
@@ -116,6 +143,7 @@ namespace libtorrent
 		}
 #endif
 		return ret;
+#endif // TORRENT_BUILD_SIMULATOR
 	}
 }
 

src/session_impl.cpp

@@ -114,6 +114,7 @@ const rlim_t rlim_infinity = RLIM_INFINITY;
 #include "libtorrent/torrent_handle.hpp"
 #include "libtorrent/choker.hpp"
 #include "libtorrent/error.hpp"
+#include "libtorrent/platform_util.hpp"
 
 #ifndef TORRENT_DISABLE_LOGGING
 
@@ -523,33 +524,19 @@ namespace aux {
 
 #endif // TORRENT_DISABLE_LOGGING
 
-#if TORRENT_USE_RLIMIT
 		// ---- auto-cap max connections ----
-
-		struct rlimit rl;
-		if (getrlimit(RLIMIT_NOFILE, &rl) == 0)
-		{
+		int max_files = max_open_files();
+		// deduct some margin for epoll/kqueue, log files,
+		// futexes, shared objects etc.
+		// 80% of the available file descriptors should go to connections
+		m_settings.set_int(settings_pack::connections_limit, (std::min)(
+			m_settings.get_int(settings_pack::connections_limit)
+			, (std::max)(5, (max_files - 20) * 8 / 10)));
+		// 20% goes towards regular files (see disk_io_thread)
 #ifndef TORRENT_DISABLE_LOGGING
-			session_log(" max number of open files: %d", int(rl.rlim_cur));
-#endif
-			// deduct some margin for epoll/kqueue, log files,
-			// futexes, shared objects etc.
-			rl.rlim_cur -= 20;
+		session_log("   max connections: %d", m_settings.get_int(settings_pack::connections_limit));
+		session_log("   max files: %d", max_files);
 
-			// 80% of the available file descriptors should go to connections
-			m_settings.set_int(settings_pack::connections_limit, (std::min)(
-				m_settings.get_int(settings_pack::connections_limit)
-				, int(rl.rlim_cur * 8 / 10)));
-			// 20% goes towards regular files (see disk_io_thread)
-#ifndef TORRENT_DISABLE_LOGGING
-			session_log("   max connections: %d", m_settings.get_int(settings_pack::connections_limit));
-			session_log("   max files: %d", int(rl.rlim_cur * 2 / 10));
-#endif
-		}
-#endif // TORRENT_USE_RLIMIT
-
-
-#ifndef TORRENT_DISABLE_LOGGING
 		session_log(" generated peer ID: %s", m_peer_id.to_string().c_str());
 #endif
 
@@ -6292,21 +6279,15 @@ retry:
 
 	void session_impl::update_connections_limit()
 	{
-		if (m_settings.get_int(settings_pack::connections_limit) <= 0)
-		{
-			m_settings.set_int(settings_pack::connections_limit, (std::numeric_limits<int>::max)());
-#if TORRENT_USE_RLIMIT
-			rlimit l;
-			if (getrlimit(RLIMIT_NOFILE, &l) == 0
-				&& l.rlim_cur != rlim_infinity)
-			{
-				m_settings.set_int(settings_pack::connections_limit
-					, l.rlim_cur - m_settings.get_int(settings_pack::file_pool_size));
-				if (m_settings.get_int(settings_pack::connections_limit) < 5)
-					m_settings.set_int(settings_pack::connections_limit, 5);
-			}
-#endif
-		}
+		int limit = m_settings.get_int(settings_pack::connections_limit);
+
+		if (limit <= 0)
+			limit = (std::numeric_limits<int>::max)();
+
+		limit = (std::max)(5, (std::min)(limit
+				, max_open_files() - 20 - m_settings.get_int(settings_pack::file_pool_size)));
+
+		m_settings.set_int(settings_pack::connections_limit, limit);
 
 		if (num_connections() > m_settings.get_int(settings_pack::connections_limit)
 			&& !m_torrents.empty())