improved support for out-of-memory conditions

src/bt_peer_connection.cpp

@@ -382,6 +382,7 @@ namespace libtorrent
 #endif
 
 		buffer::interval send_buf = allocate_send_buffer(dh_key_len + pad_size);
+		if (send_buf.begin == 0) return; // out of memory
 
 		std::copy(m_DH_key_exchange->get_local_key(),
 				   m_DH_key_exchange->get_local_key() + dh_key_len,
@@ -416,6 +417,7 @@ namespace libtorrent
 		// synchash,skeyhash,vc,crypto_provide,len(pad),pad,len(ia)
 		buffer::interval send_buf = 
 			allocate_send_buffer(20 + 20 + 8 + 4 + 2 + pad_size + 2);
+		if (send_buf.begin == 0) return; // out of memory
 
 		// sync hash (hash('req1',S))
 		h.reset();
@@ -490,6 +492,7 @@ namespace libtorrent
 
 		const int buf_size = 8 + 4 + 2 + pad_size;
 		buffer::interval send_buf = allocate_send_buffer(buf_size);
+		if (send_buf.begin == 0) return; // out of memory
 		write_pe_vc_cryptofield(send_buf, crypto_select, pad_size);
 
 		m_RC4_handler->encrypt(send_buf.end - buf_size, buf_size);
@@ -682,6 +685,7 @@ namespace libtorrent
 		const int string_len = sizeof(version_string)-1;
 
 		buffer::interval i = allocate_send_buffer(1 + string_len + 8 + 20 + 20);
+		if (i.begin == 0) return; // out of memory
 		// length of version string
 		*i.begin = string_len;
 		++i.begin;
@@ -1449,6 +1453,7 @@ namespace libtorrent
 		const int packet_size = (num_pieces + 7) / 8 + 5;
 	
 		buffer::interval i = allocate_send_buffer(packet_size);	
+		if (i.begin == 0) return; // out of memory
 
 		detail::write_int32(packet_size - 4, i.begin);
 		detail::write_uint8(msg_bitfield, i.begin);
@@ -1537,6 +1542,7 @@ namespace libtorrent
 
 		// make room for message
 		buffer::interval i = allocate_send_buffer(6 + msg.size());
+		if (i.begin == 0) return; // out of memory
 		
 		// write the length of the message
 		detail::write_int32((int)msg.size() + 2, i.begin);
@@ -1635,11 +1641,6 @@ namespace libtorrent
 			, boost::bind(&session_impl::free_disk_buffer
 			, boost::ref(m_ses), _1));
 
-/*
-		buffer::interval i = allocate_send_buffer(r.length);
-		std::memcpy(i.begin, buffer, r.length);
-		t->filesystem().free_buffer(buffer);
-*/	
 		m_payloads.push_back(range(send_buffer_size() - r.length, r.length));
 		setup_send();
 	}

src/peer_connection.cpp

@@ -2673,6 +2673,11 @@ namespace libtorrent
 		if (size <= 0) return;
 
 		std::pair<char*, int> buffer = m_ses.allocate_buffer(size);
+		if (buffer.first == 0)
+		{
+			disconnect("out of memory");
+			return;
+		}
 		TORRENT_ASSERT(buffer.second >= size);
 		std::memcpy(buffer.first, buf, size);
 		m_send_buffer.append_buffer(buffer.first, buffer.second, size
@@ -2693,6 +2698,11 @@ namespace libtorrent
 		if (insert == 0)
 		{
 			std::pair<char*, int> buffer = m_ses.allocate_buffer(size);
+			if (buffer.first == 0)
+			{
+				disconnect("out of memory");
+				return buffer::interval(0, 0);
+			}
 			TORRENT_ASSERT(buffer.second >= size);
 			m_send_buffer.append_buffer(buffer.first, buffer.second, size
 				, bind(&session_impl::free_buffer, boost::ref(m_ses), _1, buffer.second));

src/session_impl.cpp

@@ -1280,10 +1280,21 @@ namespace detail
 				torrent& t = *i->second;
 				if (t.want_more_peers())
 				{
-					if (t.try_connect_peer())
+					try
 					{
-						--max_connections;
-						steps_since_last_connect = 0;
+						if (t.try_connect_peer())
+						{
+							--max_connections;
+							steps_since_last_connect = 0;
+						}
+					}
+					catch (std::bad_alloc&)
+					{
+						// we ran out of memory trying to connect to a peer
+						// lower the global limit to the number of peers
+						// we already have
+						m_max_connections = num_connections();
+						if (m_max_connections < 2) m_max_connections = 2;
 					}
 				}
 				++m_next_connect_torrent;