Function CollectInput

source/hook.cpp:2275–2598

bool CollectInput(KBDLLHOOKSTRUCT &aEvent, const vk_type aVK, const sc_type aSC, bool aKeyUp, bool aIsIgnored
	, KeyHistoryItem *pKeyHistoryCurr, WPARAM &aHotstringWparamToPost, LPARAM &aHotstringLparamToPost)
// Caller is responsible for having initialized aHotstringWparamToPost to HOTSTRING_INDEX_INVALID.
// Returns true if the caller should treat the key as visible (non-suppressed).
// Always use the parameter vk rather than event.vkCode because the caller or caller's caller
// might have adjusted vk, namely to make it a left/right specific modifier key rather than a
// neutral one.
{
	// Transcription is done only once for all layers, so do this if any layer requests it:
	bool transcribe_modified_keys = false;

	for (auto *input = g_input; input; input = input->Prev)
	{
		if (input->InProgress() && input->IsInteresting(aEvent))
		{
			if (   aKeyUp && input->ScriptObject && input->ScriptObject->onKeyUp
				&& ( ((input->KeySC[aSC] | input->KeyVK[aVK]) & INPUT_KEY_NOTIFY)
					|| input->NotifyNonText && !((input->KeyVK[aVK]) & INPUT_KEY_IS_TEXT) )   )
			{
				PostMessage(g_hWnd, AHK_INPUT_KEYUP, (WPARAM)input, (aSC << 16) | aVK);
			}
			if (aKeyUp && (input->KeySC[aSC] & INPUT_KEY_DOWN_SUPPRESSED))
			{
				input->KeySC[aSC] &= ~INPUT_KEY_DOWN_SUPPRESSED;
				return false;
			}
			if (aKeyUp && (input->KeyVK[aVK] & INPUT_KEY_DOWN_SUPPRESSED))
			{
				input->KeyVK[aVK] &= ~INPUT_KEY_DOWN_SUPPRESSED;
				return false;
			}

			if (input->TranscribeModifiedKeys)
				transcribe_modified_keys = true;
		}
	}

	// The checks above suppress key-up if key-down was suppressed and the Input is still active.
	// Otherwise, avoid suppressing key-up since it may result in the key getting stuck down.
	// At the very least, this is needed for cases where a user presses a #z hotkey, for example,
	// to initiate an Input.  When the user releases the LWIN/RWIN key during the input, that
	// up-event should not be suppressed otherwise the modifier key would get "stuck down".  
	if (aKeyUp)
		return true;

	static vk_type sPendingDeadKeyVK = 0;
	static sc_type sPendingDeadKeySC = 0; // Need to track this separately because sometimes default VK-to-SC mapping isn't correct.
	static bool sPendingDeadKeyUsedShift = false;
	static bool sPendingDeadKeyUsedAltGr = false;
	
	bool transcribe_key = true;
	
	// Don't unconditionally transcribe modified keys such as Ctrl-C because calling ToAsciiEx() on
	// some such keys (e.g. Ctrl-LeftArrow or RightArrow if I recall correctly), disrupts the native
	// function of those keys.  That is the reason for the existence of the
	// g_input.TranscribeModifiedKeys option.
	// Fix for v1.0.38: Below now uses g_modifiersLR_logical vs. g_modifiersLR_physical because
	// it's the logical state that determines what will actually be produced on the screen and