Function Test_send_buffer_full

tests/test_connection.cpp:1470–1559

}

void Test_send_buffer_full()
{
	TEST_Printf( "***************************************************\n" );
	TEST_Printf( "Test: SendMessages batch stop and retry on buffer full\n" );
	TEST_Printf( "***************************************************\n" );

	// Network loopback so we get real rate limiting
	HSteamNetConnection hSender, hRecver;
	assert( SteamNetworkingSockets()->CreateSocketPair( &hSender, &hRecver, true, nullptr, nullptr ) );
	SteamNetworkingSockets()->SetConnectionName( hSender, "sender" );
	SteamNetworkingSockets()->SetConnectionName( hRecver, "recver" );

	// Low send rate so the buffer stays full long enough to observe
	const int k_nSendRate = 64 * 1024;
	SteamNetworkingUtils()->SetConnectionConfigValueInt32( hSender, k_ESteamNetworkingConfig_SendRateMin, k_nSendRate );
	SteamNetworkingUtils()->SetConnectionConfigValueInt32( hSender, k_ESteamNetworkingConfig_SendRateMax, k_nSendRate );

	// Buffer fits one 100K message but not two, so msg[1] overflows and msg[2] is never attempted
	const int k_cbMsg = 100 * 1024;
	const int k_nSendBuffer = 160 * 1024;
	SteamNetworkingUtils()->SetConnectionConfigValueInt32( hSender, k_ESteamNetworkingConfig_SendBufferSize, k_nSendBuffer );

	// Prepare three reliable messages
	SteamNetworkingMessage_t *pMessages[3];
	for ( int i = 0; i < 3; ++i )
	{
		pMessages[i] = SteamNetworkingUtils()->AllocateMessage( k_cbMsg );
		pMessages[i]->m_conn = hSender;
		pMessages[i]->m_nFlags = k_nSteamNetworkingSend_Reliable;
	}

	// Send all three at once. Pass bDeleteFailedMessages=false so the library
	// leaves failed/not-attempted message pointers in place for retry.
	int64 results[3] = {};
	SteamNetworkingSockets()->SendMessages( 3, pMessages, results, /*bDeleteFailedMessages=*/false );

	// First message fits in the 160K buffer: should succeed
	assert( results[0] > 0 );
	assert( pMessages[0] == nullptr ); // library took ownership

	// Second message overflows the buffer: should fail
	assert( results[1] == -k_EResultLimitExceeded );
	assert( pMessages[1] != nullptr ); // we still own it; can retry

	// Third message was never attempted because the second failed
	assert( results[2] == 0 );
	assert( pMessages[2] != nullptr ); // we still own it; can retry

	TEST_Printf( "Initial send: msg[0]=#%lld succeeded, msg[1]=LimitExceeded, msg[2]=not attempted.\n", results[0] );

	// Retry the two remaining messages one at a time.  The buffer only holds one
	// 100K message, so we must wait for space before each retry.
	SteamNetworkingMessage_t *pRetry[2] = { pMessages[1], pMessages[2] };
	for ( int i = 0; i < 2; ++i )
	{
		TEST_Printf( "Waiting for buffer space (retry %d)...\n", i );
		SteamNetworkingMicroseconds usecDeadline = SteamNetworkingUtils()->GetLocalTimestamp() + 10 * 1000000LL;
		for (;;)