Method ControlGetListBox

source/script_gui.cpp:1750–1823

ResultType GuiType::ControlGetListBox(ResultToken &aResultToken, GuiControlType &aControl, ValueModeType aMode)
{
	bool position_mode = (aMode == Value_Mode || (aMode == Submit_Mode && (aControl.attrib & GUI_CONTROL_ATTRIB_ALTSUBMIT)));
	if (GetWindowLong(aControl.hwnd, GWL_STYLE) & (LBS_EXTENDEDSEL|LBS_MULTIPLESEL))
	{
		LRESULT sel_count = SendMessage(aControl.hwnd, LB_GETSELCOUNT, 0, 0);
		if (sel_count < 1)  // <=0 to check for LB_ERR too (but it should be impossible in this case).
			_o_return_empty;
		int *item = (int *)malloc(sel_count * sizeof(int)); // dynamic since there can be a very large number of items.
		if (!item)
			_o_throw_oom;
		sel_count = SendMessage(aControl.hwnd, LB_GETSELITEMS, (WPARAM)sel_count, (LPARAM)item);
		if (sel_count < 1)  // 0 or LB_ERR, but both these conditions should be impossible in this case.
		{
			free(item);
			_o_return_empty;
		}

		// Create object for storing the selected items.
		auto ret = Array::Create();
		if (!ret)
		{
			free(item);
			_o_throw_oom;
		}

		for (LRESULT length = sel_count - 1, i = 0; i < sel_count; ++i)
		{
			if (position_mode) // Caller wants the positions, not the text.
				ret->Append(item[i] + 1); // +1 to convert from zero-based to 1-based.
			else // Store item text vs. position.
			{
				LRESULT item_length = SendMessage(aControl.hwnd, LB_GETTEXTLEN, (WPARAM)item[i], 0);
				if (item_length == LB_ERR) // Realistically impossible based on MSDN.
				{
					free(item);
					ret->Release();
					_o_throw(_T("LB_GETTEXTLEN")); // Short msg since so rare.
				}
				LPTSTR temp = tmalloc(item_length+1);
				if (!temp)
				{
					free(item);
					ret->Release();
					_o_throw_oom; // Short msg since so rare.
				}
				LRESULT lr = SendMessage(aControl.hwnd, LB_GETTEXT, (WPARAM)item[i], (LPARAM)temp);
				if (lr > 0) // Given the way it was called, LB_ERR (-1) should be impossible based on MSDN docs.
					ret->Append(temp, item_length);
				free(temp);
			}
		}

		free(item);
		_o_return(ret);
	}
	else // Single-select ListBox style.
	{