Module keyboardHandler
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Source Code for Module keyboardHandler

#keyboardHandler.py
#A part of NonVisual Desktop Access (NVDA)
#This file is covered by the GNU General Public License.
#See the file COPYING for more details.
#Copyright (C) 2006-2010 Michael Curran , James Teh , Peter Vágner , Aleksey Sadovoy 

"""Keyboard support"""

import time
import wx
import winUser
import vkCodes
import speech
import ui
from keyLabels import localizedKeyLabels
from logHandler import log
import queueHandler
import config
import api
import winInputHook
import inputCore

ignoreInjected=False

# Fake vk codes.
# These constants should be assigned to the name that NVDA will use for the key.
VK_WIN = "windows"

#: Keys which have been trapped by NVDA and should not be passed to the OS.
trappedKeys=set()
#: Tracks the number of keys passed through by request of the user.
#: If -1, pass through is disabled.
#: If 0 or higher then key downs and key ups will be passed straight through.
passKeyThroughCount=-1
#: The last key down passed through by request of the user.
lastPassThroughKeyDown = None
#: The last NVDA modifier key that was pressed with no subsequent key presses.
lastNVDAModifier = None
#: When the last NVDA modifier key was released.
lastNVDAModifierReleaseTime = None
#: Indicates that the NVDA modifier's special functionality should be bypassed until a key is next released.
bypassNVDAModifier = False
#: The modifiers currently being pressed.
currentModifiers = set()
#: A counter which is incremented each time a key is pressed.
#: Note that this may be removed in future, so reliance on it should generally be avoided.
#: @type: int
keyCounter = 0

def passNextKeyThrough():
        global passKeyThroughCount
        if passKeyThroughCount==-1:
                passKeyThroughCount=0

def isNVDAModifierKey(vkCode,extended):
        if config.conf["keyboard"]["useNumpadInsertAsNVDAModifierKey"] and vkCode==winUser.VK_INSERT and not extended:
                return True
        elif config.conf["keyboard"]["useExtendedInsertAsNVDAModifierKey"] and vkCode==winUser.VK_INSERT and extended:
                return True
        elif config.conf["keyboard"]["useCapsLockAsNVDAModifierKey"] and vkCode==winUser.VK_CAPITAL:
                return True
        else:
                return False

def internal_keyDownEvent(vkCode,scanCode,extended,injected):
        """Event called by winInputHook when it receives a keyDown.
        """
        try:
                global lastNVDAModifier, lastNVDAModifierReleaseTime, bypassNVDAModifier, passKeyThroughCount, lastPassThroughKeyDown, currentModifiers, keyCounter
                #Injected keys should be ignored
                if ignoreInjected and injected:
                        return True

                keyCode = (vkCode, extended)

                if passKeyThroughCount >= 0:
                        # We're passing keys through.
                        if lastPassThroughKeyDown != keyCode:
                                # Increment the pass key through count.
                                # We only do this if this isn't a repeat of the previous key down, as we don't receive key ups for repeated key downs.
                                passKeyThroughCount += 1
                                lastPassThroughKeyDown = keyCode
                        return True

                keyCounter += 1
                gesture = KeyboardInputGesture(currentModifiers, vkCode, scanCode, extended)
                if bypassNVDAModifier or (keyCode == lastNVDAModifier and lastNVDAModifierReleaseTime and time.time() - lastNVDAModifierReleaseTime < 0.5):
                        # The user wants the key to serve its normal function instead of acting as an NVDA modifier key.
                        # There may be key repeats, so ensure we do this until they stop.
                        bypassNVDAModifier = True
                        gesture.isNVDAModifierKey = False
                lastNVDAModifierReleaseTime = None
                if gesture.isNVDAModifierKey:
                        lastNVDAModifier = keyCode
                else:
                        # Another key was pressed after the last NVDA modifier key, so it should not be passed through on the next press.
                        lastNVDAModifier = None
                if gesture.isModifier:
                        if gesture.speechEffectWhenExecuted in (gesture.SPEECHEFFECT_PAUSE, gesture.SPEECHEFFECT_RESUME) and keyCode in currentModifiers:
                                # Ignore key repeats for the pause speech key to avoid speech stuttering as it continually pauses and resumes.
                                return True
                        currentModifiers.add(keyCode)

                try:
                        inputCore.manager.executeGesture(gesture)
                        trappedKeys.add(keyCode)
                        return False
                except inputCore.NoInputGestureAction:
                        if gesture.isNVDAModifierKey:
                                # Never pass the NVDA modifier key to the OS.
                                trappedKeys.add(keyCode)
                                return False
        except:
                log.error("internal_keyDownEvent", exc_info=True)
        return True

def internal_keyUpEvent(vkCode,scanCode,extended,injected):
        """Event called by winInputHook when it receives a keyUp.
        """
        try:
                global lastNVDAModifier, lastNVDAModifierReleaseTime, bypassNVDAModifier, passKeyThroughCount, lastPassThroughKeyDown, currentModifiers
                if ignoreInjected and injected:
                        return True

                keyCode = (vkCode, extended)

                if passKeyThroughCount >= 1:
                        if lastPassThroughKeyDown == keyCode:
                                # This key has been released.
                                lastPassThroughKeyDown = None
                        passKeyThroughCount -= 1
                        if passKeyThroughCount == 0:
                                passKeyThroughCount = -1
                        return True

                if lastNVDAModifier and keyCode == lastNVDAModifier:
                        # The last pressed NVDA modifier key is being released and there were no key presses in between.
                        # The user may want to press it again quickly to pass it through.
                        lastNVDAModifierReleaseTime = time.time()
                # If we were bypassing the NVDA modifier, stop doing so now, as there will be no more repeats.
                bypassNVDAModifier = False

                currentModifiers.discard(keyCode)

                if keyCode in trappedKeys:
                        trappedKeys.remove(keyCode)
                        return False
        except:
                log.error("", exc_info=True)
        return True

#Register internal key press event with  operating system

def initialize():
        """Initialises keyboard support."""
        winInputHook.initialize()
        winInputHook.setCallbacks(keyDown=internal_keyDownEvent,keyUp=internal_keyUpEvent)

def terminate():
        winInputHook.terminate()

class KeyboardInputGesture(inputCore.InputGesture):
        """A key pressed on the traditional system keyboard.
        """

        #: All normal modifier keys, where modifier vk codes are mapped to a more general modifier vk code or C{None} if not applicable.
        #: @type: dict
        NORMAL_MODIFIER_KEYS = {
                winUser.VK_LCONTROL: winUser.VK_CONTROL,
                winUser.VK_RCONTROL: winUser.VK_CONTROL,
                winUser.VK_LSHIFT: winUser.VK_SHIFT,
                winUser.VK_RSHIFT: winUser.VK_SHIFT,
                winUser.VK_LMENU: winUser.VK_MENU,
                winUser.VK_RMENU: winUser.VK_MENU,
                winUser.VK_LWIN: VK_WIN,
                winUser.VK_RWIN: VK_WIN,
        }

        #: All possible toggle key vk codes.
        #: @type: frozenset
        TOGGLE_KEYS = frozenset((winUser.VK_CAPITAL, winUser.VK_NUMLOCK, winUser.VK_SCROLL))

        #: All possible keyboard layouts, where layout names are mapped to localised layout names.
        #: @type: dict
        LAYOUTS = {
                "desktop": _("desktop"),
                "laptop": _("laptop"),
        }

        @classmethod
        def getVkName(cls, vkCode, isExtended):
                if isinstance(vkCode, str):
                        return vkCode
                name = vkCodes.byCode.get((vkCode, isExtended))
                if not name and isExtended is not None:
                        # Whether the key is extended doesn't matter for many keys, so try None.
                        name = vkCodes.byCode.get((vkCode, None))
                return name if name else ""

        def __init__(self, modifiers, vkCode, scanCode, isExtended):
                #: The keyboard layout in which this gesture was created.
                #: @type: str
                self.layout = config.conf["keyboard"]["keyboardLayout"]
                self.modifiers = modifiers = set(modifiers)
                # Don't double up if this is a modifier key repeat.
                modifiers.discard((vkCode, isExtended))
                if vkCode in (winUser.VK_DIVIDE, winUser.VK_MULTIPLY, winUser.VK_SUBTRACT, winUser.VK_ADD) and winUser.getKeyState(winUser.VK_NUMLOCK) & 1:
                        # Some numpad keys have the same vkCode regardless of numlock.
                        # For these keys, treat numlock as a modifier.
                        modifiers.add((winUser.VK_NUMLOCK, False))
                self.generalizedModifiers = set((self.NORMAL_MODIFIER_KEYS.get(mod) or mod, extended) for mod, extended in modifiers)
                self.vkCode = vkCode
                self.scanCode = scanCode
                self.isExtended = isExtended
                super(KeyboardInputGesture, self).__init__()

        def _get_isNVDAModifierKey(self):
                return isNVDAModifierKey(self.vkCode, self.isExtended)

        def _get_isModifier(self):
                return self.vkCode in self.NORMAL_MODIFIER_KEYS or self.isNVDAModifierKey

        def _get_mainKeyName(self):
                if self.isNVDAModifierKey:
                        return "NVDA"

                name = self.getVkName(self.vkCode, self.isExtended)
                if name:
                        return name

                if 32 < self.vkCode < 128:
                        return unichr(self.vkCode).lower()
                vkChar = winUser.user32.MapVirtualKeyW(self.vkCode, winUser.MAPVK_VK_TO_CHAR)
                if vkChar>0:
                        return unichr(vkChar).lower()

                return winUser.getKeyNameText(self.scanCode, self.isExtended)

        def _get_modifierNames(self):
                modTexts = set()
                for modVk, modExt in self.generalizedModifiers:
                        if isNVDAModifierKey(modVk, modExt):
                                modTexts.add("NVDA")
                        else:
                                modTexts.add(self.getVkName(modVk, None))

                return modTexts

        def _get__keyNamesInDisplayOrder(self):
                return tuple(self.modifierNames) + (self.mainKeyName,)

        def _get_logIdentifier(self):
                return u"kb({layout}):{key}".format(layout=self.layout,
                        key="+".join(self._keyNamesInDisplayOrder))

        def _get_displayName(self):
                return "+".join(localizedKeyLabels.get(key, key) for key in self._keyNamesInDisplayOrder)

        def _get_identifiers(self):
                keyNames = set(self.modifierNames)
                keyNames.add(self.mainKeyName)
                keyName = "+".join(keyNames).lower()
                return (
                        u"kb({layout}):{key}".format(layout=self.layout, key=keyName),
                        u"kb:{key}".format(key=keyName)
                )

        def _get_shouldReportAsCommand(self):
                if self.isExtended and winUser.VK_VOLUME_MUTE <= self.vkCode <= winUser.VK_VOLUME_UP:
                        # Don't report volume controlling keys.
                        return False
                # Aside from space, a key name of more than 1 character is a command.
                if self.vkCode != winUser.VK_SPACE and len(self.mainKeyName) > 1:
                        return True
                # If this key has modifiers other than shift, it is a command; e.g. shift+f is text, but control+f is a command.
                modifiers = self.generalizedModifiers
                if modifiers and (len(modifiers) > 1 or tuple(modifiers)[0][0] != winUser.VK_SHIFT):
                        return True
                return False

        def _get_speechEffectWhenExecuted(self):
                if inputCore.manager.isInputHelpActive:
                        return self.SPEECHEFFECT_CANCEL
                if self.isExtended and winUser.VK_VOLUME_MUTE <= self.vkCode <= winUser.VK_VOLUME_UP:
                        return None
                if self.vkCode in (winUser.VK_SHIFT, winUser.VK_LSHIFT, winUser.VK_RSHIFT):
                        return self.SPEECHEFFECT_RESUME if speech.isPaused else self.SPEECHEFFECT_PAUSE
                return self.SPEECHEFFECT_CANCEL

        def reportExtra(self):
                if self.vkCode in self.TOGGLE_KEYS:
                        wx.CallLater(30, self._reportToggleKey)

        def _reportToggleKey(self):
                toggleState = winUser.getKeyState(self.vkCode) & 1
                key = self.mainKeyName
                ui.message(u"{key} {state}".format(
                        key=localizedKeyLabels.get(key, key),
                        state=_("on") if toggleState else _("off")))

        def send(self):
                global ignoreInjected
                keys = []
                for vk, ext in self.generalizedModifiers:
                        if vk == VK_WIN:
                                if winUser.getKeyState(winUser.VK_LWIN) & 32768 or winUser.getKeyState(winUser.VK_RWIN) & 32768:
                                        # Already down.
                                        continue
                                vk = winUser.VK_LWIN
                        elif winUser.getKeyState(vk) & 32768:
                                # Already down.
                                continue
                        keys.append((vk, 0, ext))
                keys.append((self.vkCode, self.scanCode, self.isExtended))

                try:
                        ignoreInjected=True
                        if winUser.getKeyState(self.vkCode) & 32768:
                                # This key is already down, so send a key up for it first.
                                winUser.keybd_event(self.vkCode, self.scanCode, self.isExtended + 2, 0)

                        # Send key down events for these keys.
                        for vk, scan, ext in keys:
                                winUser.keybd_event(vk, scan, ext, 0)
                        # Send key up events for the keys in reverse order.
                        for vk, scan, ext in reversed(keys):
                                winUser.keybd_event(vk, scan, ext + 2, 0)

                        if not queueHandler.isPendingItems(queueHandler.eventQueue):
                                time.sleep(0.01)
                                wx.Yield()
                finally:
                        ignoreInjected=False

        @classmethod
        def fromName(cls, name):
                """Create an instance given a key name.
                @param name: The key name.
                @type name: str
                @return: A gesture for the specified key.
                @rtype: L{KeyboardInputGesture}
                """
                keyNames = name.split("+")
                keys = []
                for keyName in keyNames:
                        if keyName == VK_WIN:
                                vk = winUser.VK_LWIN
                                ext = False
                        elif len(keyName) == 1:
                                ext = False
                                requiredMods, vk = winUser.VkKeyScan(keyName)
                                if requiredMods & 1:
                                        keys.append((winUser.VK_SHIFT, False))
                                if requiredMods & 2:
                                        keys.append((winUser.VK_CONTROL, False))
                                if requiredMods & 4:
                                        keys.append((winUser.VK_MENU, False))
                                # Not sure whether we need to support the Hankaku modifier (& 8).
                        else:
                                vk, ext = vkCodes.byName[keyName.lower()]
                                if ext is None:
                                        ext = False
                        keys.append((vk, ext))

                if not keys:
                        raise ValueError

                return cls(keys[:-1], vk, 0, ext)