Module synthDriverHandler
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Source Code for Module synthDriverHandler

#synthDriverHandler.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 

from copy import deepcopy
import os
import pkgutil
import config
import baseObject
import globalVars
from logHandler import log
from  synthSettingsRing import SynthSettingsRing
import languageHandler
import speechDictHandler
import synthDrivers

_curSynth=None

def initialize():
        config.addConfigDirsToPythonPackagePath(synthDrivers)

def changeVoice(synth, voice):
        # This function can be called with no voice if the synth doesn't support the voice setting (only has one voice).
        if voice:
                synth.voice = voice
        c=config.conf["speech"][synth.name]
        c.configspec=synth.getConfigSpec()
        config.conf.validate(config.val, copy = True,section = c)
        #start or update the synthSettingsRing
        if globalVars.settingsRing: globalVars.settingsRing.updateSupportedSettings(synth)
        else:  globalVars.settingsRing = SynthSettingsRing(synth)
        speechDictHandler.loadVoiceDict(synth)

def _getSynthDriver(name):
        return __import__("synthDrivers.%s" % name, globals(), locals(), ("synthDrivers",)).SynthDriver

def getSynthList():
        synthList=[]
        for loader, name, isPkg in pkgutil.iter_modules(synthDrivers.__path__):
                if name.startswith('_'):
                        continue
                try:
                        synth=_getSynthDriver(name)
                except:
                        log.error("Error while importing SynthDriver %s"%name,exc_info=True)
                        continue
                try:
                        if synth.check():
                                synthList.append((synth.name,synth.description))
                        else:
                                log.debugWarning("Synthesizer '%s' doesn't pass the check, excluding from list"%name)
                except:
                        log.error("",exc_info=True)
        return synthList

def getSynth():
        return _curSynth

def setSynth(name):
        global _curSynth
        if name is None: 
                _curSynth.terminate()
                _curSynth=None
                return True
        if name=='auto':
                name='espeak'
        if _curSynth:
                _curSynth.cancel()
                _curSynth.terminate()
                prevSynthName = _curSynth.name
                _curSynth = None
        else:
                prevSynthName = None
        try:
                newSynth=_getSynthDriver(name)()
                if name in config.conf["speech"]:
                        newSynth.loadSettings()
                else:
                        # Create the new section.
                        config.conf["speech"][name]={}
                        if newSynth.isSupported("voice"):
                                voice=newSynth.voice
                        else:
                                voice=None
                        # We need to call changeVoice here so that required initialisation can be performed.
                        changeVoice(newSynth,voice)
                        newSynth.saveSettings() #save defaults
                _curSynth=newSynth
                config.conf["speech"]["synth"]=name
                log.info("Loaded synthDriver %s"%name)
                return True
        except:
                log.error("setSynth", exc_info=True)
                if prevSynthName:
                        setSynth(prevSynthName)
                elif name not in ('espeak','silence'):
                        setSynth('espeak')
                elif name=='espeak':
                        setSynth('silence')
                return False

class SynthSetting(object):
        """Represents a synthesizer setting such as voice or variant.
        """
        #: Configuration specification of this particular setting for config file validator.
        #: @type: str
        configSpec="string(default=None)"

        def __init__(self,name,i18nName,availableInSynthSettingsRing=True):
                """
                @param name: internal name of the setting
                @type name: str
                @param i18nName: the localized string
                @type i18nName: str
                @param availableInSynthSettingsRing: Will this option be available in synthesizer settings ring?
                @type availableInSynthSettingsRing: bool
                """
                self.name=name
                self.i18nName=i18nName
                self.availableInSynthSettingsRing=availableInSynthSettingsRing

class NumericSynthSetting(SynthSetting):
        """Represents a numeric synthesizer setting such as rate, volume or pitch."""
        configSpec="integer(default=50,min=0,max=100)"

        def __init__(self,name,i18nName,availableInSynthSettingsRing=True,minStep=1,normalStep=5,largeStep=10):
                """
                @param minStep: Specifies the minimum step between valid values for each numeric setting. For example, if L{minStep} is set to 10, setting values can only be multiples of 10; 10, 20, 30, etc.
                @type minStep: int
                @param normalStep: Specifies the step between values that a user will normally prefer. This is used in the settings ring.
                @type normalStep: int
                @param largeStep: Specifies the step between values if a large adjustment is desired. This is used for pageUp/pageDown on sliders in the Voice Settings dialog.
                @type largeStep: int
                @note: If necessary, the step values will be normalised so that L{minStep} <= L{normalStep} <= L{largeStep}.
                """
                super(NumericSynthSetting,self).__init__(name,i18nName,availableInSynthSettingsRing)
                self.minStep=minStep
                self.normalStep=max(normalStep,minStep)
                self.largeStep=max(largeStep,self.normalStep)

class BooleanSynthSetting(SynthSetting):
        """Represents a boolean synthesiser setting such as rate boost.
        """
        configSpec = "boolean(default=False)"

        def __init__(self, name, i18nName, availableInSynthSettingsRing=False):
                super(BooleanSynthSetting, self).__init__(name, i18nName, availableInSynthSettingsRing)

class SynthDriver(baseObject.AutoPropertyObject):
        """Abstract base synthesizer driver.
        Each synthesizer driver should be a separate Python module in the root synthDrivers directory containing a SynthDriver class which inherits from this base class.
        
        At a minimum, synth drivers must set L{name} and L{description} and override the L{check} method.
        L{supportedSettings} should be set as appropriate for the settings supported by the synthesiser.
        There are factory functions to create L{SynthSetting} instances for common settings; e.g. L{VoiceSetting} and L{RateSetting}.
        The properties for each setting (e.g. L{voice} and L{pitch}) are created by overriding getters and setters;
        for example, L{_get_pitch} and L{_set_pitch} for L{pitch}.
        The methods L{speakText}, L{speakCharacter}, L{cancel} and L{pause} should be overridden as appropriate.
        If L{speakCharacter} is not overridden, L{speakText} will be used by default.
        @ivar supportedSettings: The settings supported by the synthesiser.
        @type supportedSettings: list or tuple of L{SynthSetting}
        @ivar voice: Unique string identifying the current voice.
        @type voice: str
        @ivar availableVoices: The available voices.
        @type availableVoices: OrderedDict of L{VoiceInfo} keyed by VoiceInfo's ID
        @ivar pitch: The current pitch; ranges between 0 and 100.
        @type pitch: int
        @ivar rate: The current rate; ranges between 0 and 100.
        @type rate: int
        @ivar volume: The current volume; ranges between 0 and 100.
        @type volume: int
        @ivar variant: The current variant of the voice.
        @type variant: str
        @ivar availableVariants: The available variants of the voice.
        @type availableVariants: OrderedDict of [L{VoiceInfo} keyed by VoiceInfo's ID
        @ivar inflection: The current inflection; ranges between 0 and 100.
        @type inflection: int
        @ivar lastIndex: The index of the chunk of text which was last spoken or C{None} if no index.
        @type lastIndex: int
        """

        #: The name of the synth; must be the original module file name.
        #: @type: str
        name = ""
        #: A description of the synth.
        #: @type: str
        description = ""

        @classmethod
        def LanguageSetting(cls):
                """Factory function for creating a language setting."""
                return SynthSetting("language",_("&Language"))

        @classmethod
        def VoiceSetting(cls):
                """Factory function for creating voice setting."""
                return SynthSetting("voice",_("&Voice"))
        @classmethod
        def VariantSetting(cls):
                """Factory function for creating variant setting."""
                return SynthSetting("variant",_("V&ariant"))

        @classmethod
        def RateSetting(cls,minStep=1):
                """Factory function for creating rate setting."""
                return NumericSynthSetting("rate",_("&Rate"),minStep=minStep)
        @classmethod
        def VolumeSetting(cls,minStep=1):
                """Factory function for creating volume setting."""
                return NumericSynthSetting("volume",_("V&olume"),minStep=minStep,normalStep=10)
        @classmethod
        def PitchSetting(cls,minStep=1):
                """Factory function for creating pitch setting."""
                return NumericSynthSetting("pitch",_("&Pitch"),minStep=minStep)

        @classmethod
        def InflectionSetting(cls,minStep=1):
                """Factory function for creating inflection setting."""
                return NumericSynthSetting("inflection",_("&Inflection"),minStep=minStep)

        @classmethod
        def check(cls):
                """Determine whether this synth is available.
                The synth will be excluded from the list of available synths if this method returns C{False}.
                For example, if this synth requires installation and it is not installed, C{False} should be returned.
                @return: C{True} if this synth is available, C{False} if not.
                @rtype: bool
                """
                return False

        def __init__(self):
                """Initialize this synth driver.
                This method can also set default settings for the synthesizer.
                @raise Exception: If an error occurs.
                @postcondition: This driver can be used.
                """

        def terminate(self):
                """Terminate this synth driver.
                This should be used for any required clean up.
                @precondition: L{initialize} has been called.
                @postcondition: This driver can no longer be used.
                """

        def speak(self,speechSequence):
                """
                Speaks the given sequence of text and speech commands.
                This base implementation will fallback to making use of the old speakText and speakCharacter methods. But new synths should override this method to support its full functionality.
                @param speechSequence: a list of text strings and SpeechCommand objects (such as index and parameter changes).
                @type speechSequence: list of string and L{speechCommand}
                """
                import speech
                lastIndex=None
                text=""
                origSpeakFunc=self.speakText
                speechSequence=iter(speechSequence)
                while True:
                        item = next(speechSequence,None)
                        if text and (item is None or isinstance(item,(speech.IndexCommand,speech.CharacterModeCommand))):
                                # Either we're about to handle a command or this is the end of the sequence.
                                # Speak the text since the last command we handled.
                                origSpeakFunc(text,index=lastIndex)
                                text=""
                                lastIndex=None
                        if item is None:
                                # No more items.
                                break
                        if isinstance(item,basestring):
                                # Merge the text between commands into a single chunk.
                                text+=item
                        elif isinstance(item,speech.IndexCommand):
                                lastIndex=item.index
                        elif isinstance(item,speech.CharacterModeCommand):
                                origSpeakFunc=self.speakCharacter if item.state else self.speakText
                        elif isinstance(item,speech.SpeechCommand):
                                log.debugWarning("Unknown speech command: %s"%item)
                        else:
                                log.error("Unknown item in speech sequence: %s"%item)

        def speakText(self, text, index=None):
                """Speak some text.
                This method is deprecated. Instead implement speak.
                @param text: The chunk of text to speak.
                @type text: str
                @param index: An index (bookmark) to associate with this chunk of text, C{None} if no index.
                @type index: int
                @note: If C{index} is provided, the C{lastIndex} property should return this index when the synth is speaking this chunk of text.
                """
                raise NotImplementedError

        def speakCharacter(self, character, index=None):
                """Speak some character.
                This method is deprecated. Instead implement speak.
                @param character: The character to speak.
                @type character: str
                @param index: An index (bookmark) to associate with this chunk of speech, C{None} if no index.
                @type index: int
                @note: If C{index} is provided, the C{lastIndex} property should return this index when the synth is speaking this chunk of text.
                """
                self.speakText(character,index)

        def _get_lastIndex(self):
                """Obtain the index of the chunk of text which was last spoken.
                When the synth speaks text associated with a particular index, this method should return that index.
                That is, this property should update for each chunk of text spoken by the synth.
                @return: The index or C{None} if no index.
                @rtype: int
                """
                return None

        def cancel(self):
                """Silence speech immediately.
                """

        def _get_language(self):
                return self.availableVoices[self.voice].language

        def _set_language(self,language):
                raise NotImplementedError

        def _get_availableLanguages(self):
                raise NotImplementedError

        def _get_voice(self):
                raise NotImplementedError

        def _set_voice(self, value):
                pass

        def _getAvailableVoices(self):
                """fetches an ordered dictionary of voices that the synth supports.
                @returns: an OrderedDict of L{VoiceInfo} instances representing the available voices, keyed by ID
                @rtype: OrderedDict
                """
                raise NotImplementedError

        def _get_availableVoices(self):
                if not hasattr(self,'_availableVoices'):
                        self._availableVoices=self._getAvailableVoices()
                return self._availableVoices

        def _get_rate(self):
                return 0

        def _set_rate(self, value):
                pass

        def _get_pitch(self):
                return 0

        def _set_pitch(self, value):
                pass

        def _get_volume(self):
                return 0

        def _set_volume(self, value):
                pass

        def _get_variant(self):
                raise NotImplementedError

        def _set_variant(self, value):
                pass

        def _getAvailableVariants(self):
                """fetches an ordered dictionary of variants that the synth supports, keyed by ID
                @returns: an ordered dictionary of L{VoiceInfo} instances representing the available variants
                @rtype: OrderedDict
                """
                raise NotImplementedError
 
        def _get_availableVariants(self):
                if not hasattr(self,'_availableVariants'):
                        self._availableVariants=self._getAvailableVariants()
                return self._availableVariants

        def _get_supportedSettings(self):
                raise NotImplementedError

        def getConfigSpec(self):
                spec=deepcopy(config.synthSpec)
                for setting in self.supportedSettings:
                        spec[setting.name]=setting.configSpec
                return spec

        def _get_inflection(self):
                return 0

        def _set_inflection(self, value):
                pass

        def pause(self, switch):
                """Pause or resume speech output.
                @param switch: C{True} to pause, C{False} to resume (unpause).
                @type switch: bool
                """
                pass

        @classmethod
        def _paramToPercent(cls, current, min, max):
                """Convert a raw parameter value to a percentage given the current, minimum and maximum raw values.
                @param current: The current value.
                @type current: int
                @param min: The minimum value.
                @type current: int
                @param max: The maximum value.
                @type max: int
                """
                return int(round(float(current - min) / (max - min) * 100))

        @classmethod
        def _percentToParam(cls, percent, min, max):
                """Convert a percentage to a raw parameter value given the current percentage and the minimum and maximum raw parameter values.
                @param percent: The current percentage.
                @type percent: int
                @param min: The minimum raw parameter value.
                @type min: int
                @param max: The maximum raw parameter value.
                @type max: int
                """
                return int(round(float(percent) / 100 * (max - min) + min))

        def isSupported(self,settingName):
                """Checks whether given setting is supported by the synthesizer.
                @rtype: l{bool}
                """
                for s in self.supportedSettings:
                        if s.name==settingName: return True
                return False

        def saveSettings(self):
                conf=config.conf["speech"][self.name]
                for setting in self.supportedSettings:
                        conf[setting.name]=getattr(self,setting.name)

        def loadSettings(self):
                c=config.conf["speech"][self.name]
                if self.isSupported("voice"):
                        voice=c.get("voice",None)
                        try:
                                changeVoice(self,voice)
                        except LookupError:
                                log.warning("No such voice: %s" % voice)
                                # Update the configuration with the correct voice.
                                c["voice"]=self.voice
                                # We need to call changeVoice here so that required initialisation can be performed.
                                changeVoice(self,self.voice)
                else:
                        changeVoice(self,None)
                for s in self.supportedSettings:
                        if s.name=="voice" or c[s.name] is None:
                                continue
                        setattr(self,s.name,c[s.name])

        def _get_initialSettingsRingSetting (self):
                if not self.isSupported("rate") and len(self.supportedSettings)>0:
                        #Choose first as an initial one
                        for i,s in enumerate(self.supportedSettings): 
                                if s.availableInSynthSettingsRing: return i
                        return None
                for i,s in enumerate(self.supportedSettings):
                        if s.name=="rate": return i
                return None

class StringParameterInfo(object):
        """
        The base class used to represent a value of a string synth setting.
        """

        def __init__(self,ID,name):
                #: The unique identifier of the value.
                #: @type: str
                self.ID=ID
                #: The name of the value, visible to the user.
                #: @type: str
                self.name=name

class VoiceInfo(StringParameterInfo):
        """Provides information about a single synthesizer voice.
        """

        def __init__(self,ID,name,language=None):
                #: The ID of the language this voice speaks, or None if not known or the synth implements language separate from voices
                self.language=language
                super(VoiceInfo,self).__init__(ID,name)

class LanguageInfo(StringParameterInfo):
        """Holds information for a particular language"""

        def __init__(self,ID):
                """Given a language ID (locale name) the description is automatically calculated."""
                name=languageHandler.getLanguageDescription(ID)
                super(LanguageInfo,self).__init__(ID,name)