    """The PSP parser.

        This module handles the actual reading of the characters in the source
        PSP file and checking it for valid psp tokens. When it finds one,
        it calls ParseEventHandler with the characters it found.

        (c) Copyright by Jay Love, 2000 (mailto:jsliv@jslove.org)

        Permission to use, copy, modify, and distribute this software and its
        documentation for any purpose and without fee or royalty is hereby granted,
        provided that the above copyright notice appear in all copies and that
        both that copyright notice and this permission notice appear in
        supporting documentation or portions thereof, including modifications,
        that you make.

        THE AUTHORS DISCLAIM ALL WARRANTIES WITH REGARD TO
        THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
        FITNESS, IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL,
        INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
        FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
        NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
        WITH THE USE OR PERFORMANCE OF THIS SOFTWARE !

        This software is based in part on work done by the Jakarta group.

    """

    from Generators import *

    try:
        from cStringIO import StringIO
    except:
        from StringIO import StringIO

    class PSPParser:
        """The main PSP parser class.

        The PSPParser class does the actual sniffing through the input file
        looking for anything we're interested in. Basically, it starts by
        looking at the code looking for a '<' symbol. It looks at the code by
        working with a PSPReader object, which handle the current location in
        the code. When it finds one, it calls a list of functions, the xxxChecks,
        asking each if it recognizes the characters as its kind of input.
        When the check functions look at the characters, if they want it,
        they go ahead and gobble it up and set up to create it in the servlet
        when the time comes.  When they return, they return true if they accept
        the character, and the PSPReader object cursor is positioned past the
        end of the block that the check function accepted.

        """

        checklist = []

        def __init__(self, ctxt):
            self._reader = ctxt.getReader()
            self._writer = ctxt.getServletWriter()
            self._handler = None
            self.cout = StringIO() # This is where we dump straight HTML code that none of the checks want
            self.tmplStart = 0 # marks the start of HTML code
            self.tmplStop = 0 #marks the end of HTML code
            self.currentFile = self._reader.Mark().getFile()

        def setEventHandler(self, handler):
            """Set the handler this parser will use when it finds PSP code."""
            self._handler = handler

        def flushCharData(self, start, stop):
            """Dump everything to the char data handler.

            Dump all the HTML that we've accumulated over to the character data
            handler in the event handler object.

            """
            data = self.cout.getvalue()
            self.cout.close()
            if len(data) > 0: # make sure there's something there
                self._handler.handleCharData(start, stop, data)
            self.cout = StringIO()

        def commentCheck(self, handler, reader):
            """Comments just get eaten."""
            OPEN_COMMENT = '<%--'
            CLOSE_COMMENT = '--%>'
            if reader.Matches(OPEN_COMMENT):
                reader.Advance(len(OPEN_COMMENT))
                start = reader.Mark()
                stop = reader.skipUntil(CLOSE_COMMENT)
                if stop is None:
                    raise 'ParseException'
                self.flushCharData(self.tmplStart, self.tmplStop)
                return 1
            return 0

        checklist.append(commentCheck) # add this checker to the list that the parse function will call

        def checkExpression(self, handler, reader):
            """Look for "expressions" and handle them"""
            OPEN_EXPR = '<%='
            CLOSE_EXPR = '%>'
            end_open = None
            attrs = None
            if not reader.Matches(OPEN_EXPR):
                return 0
            reader.Advance(len(OPEN_EXPR)) # eat the opening tag
            if end_open is not None:
                attrs = reader.parseTagAttributes()
                reader.skipSpaces()
                if not reader.matches(end_open):
                    raise 'ParseException'
                reader.Advance(len(end_open))
                reader.skipSpaces()
            # below not implemented
            # PSPUtil.checkAttrs('Expression',attrs,validAttrs)
            reader.peekChar()
            reader.skipSpaces()
            start = reader.Mark()
            stop = reader.skipUntil(CLOSE_EXPR)
            if stop is None:
                raise 'ParserException'
            handler.setTemplateInfo(self.tmplStart, self.tmplStop)
            handler.handleExpression(start, stop, attrs)
            return 1

        checklist.append(checkExpression)

        def checkDirective(self, handler, reader):
            """Check for directives. I support two right now, page and include."""
            validDirectives = ['page', 'include']
            OPEN_DIRECTIVE = r'<%@'
            CLOSE_DIRECTIVE = r'%>'
            if reader.Matches(OPEN_DIRECTIVE):
                opening = OPEN_DIRECTIVE
                close = CLOSE_DIRECTIVE
            else:
                return 0
            start = reader.Mark()
            reader.Advance(len(OPEN_DIRECTIVE))
            match = None
            reader.skipSpaces()
            for i in validDirectives:
                if reader.Matches(i):
                    match = i
                    break
            if match is None:
                raise 'Invalid Directive'
            reader.Advance(len(match))
            # parse the directive attr:val pair dictionary
            attrs = reader.parseTagAttributes()
            # not checking for validity yet
            # if match == 'page':
            #   PSPUtils.checkAttributes('Page Directive', attrs, pageDvalidAttrs)
            # elif match == 'include':
            #   PSPUtils.checkAttributes('Include Directive', attrs, includeDvalidAttrs)
            # elif match == 'taglib':
            #   raise 'Not Implemented Error'
            # match close
            reader.skipSpaces() #skip to where we expect a close tag
            if not reader.Matches(close):
                raise 'Unterminated directive error'
            else:
                reader.Advance(len(close)) #advance past it
            stop = reader.Mark()
            handler.setTemplateInfo(self.tmplStart, self.tmplStop)
            handler.handleDirective(match, start, stop, attrs)
            return 1

        checklist.append(checkDirective)

        def checkEndBlock(self, handler, reader):
            OPEN_SCRIPT = '<%'
            CLOSE_SCRIPT = '%>'
            CLOSE_SCRIPT2 = '$%>'
            CENTER_SCRIPT = 'end'
            start = reader.Mark()
            if reader.Matches(OPEN_SCRIPT):
                reader.Advance(len(OPEN_SCRIPT))
                reader.skipSpaces()
                if reader.Matches(CENTER_SCRIPT):
                    reader.Advance(len(CENTER_SCRIPT))
                    reader.skipSpaces()
                    if reader.Matches(CLOSE_SCRIPT):
                        reader.Advance(len(CLOSE_SCRIPT))
                        handler.setTemplateInfo(self.tmplStart, self.tmplStop)
                        handler.handleEndBlock()
                        return 1
                    if reader.Matches(CLOSE_SCRIPT2):
                        reader.Advance(len(CLOSE_SCRIPT2))
                        handler.setTemplateInfo(self.tmplStart, self.tmplStop)
                        handler.handleEndBlock()
                        print ">>>>Putting a $ at the end of an end tag does nothing, I Say"
                        return 1
            # that wasn't it
            reader.reset(start)
            return 0

        checklist.append(checkEndBlock)

        def checkScript(self, handler, reader):
            """The main thing we're after. Check for embedded scripts."""
            OPEN_SCRIPT = '<%'
            CLOSE_SCRIPT = '%>'
            attrs = None
            end_open = None
            if reader.Matches(OPEN_SCRIPT):
                open = OPEN_SCRIPT
                close = CLOSE_SCRIPT
            else:
                return 0
            reader.Advance(len(open))# Matches advances it
            if end_open is not None:
                attrs = reader.parseTagAttributes()
                reader.skipSpaces()
                if not reader.Matches(end_open):
                    raise 'Unterminated script'
                reader.Advance(len(end_open))
                reader.skipSpaces()
                PSPUtils.checkAttributes('Script', attrs, ValidAttributes)
            # reader.skipSpaces() # don't skip as spaces may be significant, leave this for the generator
            start = reader.Mark()
            try:
                stop = reader.skipUntil(close)
            except EOFError:
                raise EOFError("Reached EOF while looking for ending script tag")
            if stop is None:
                raise 'Unterminated Script'
            handler.setTemplateInfo(self.tmplStart, self.tmplStop)
            handler.handleScript(start, stop, attrs)
            return 1

        checklist.append(checkScript)

        def checkScriptFile(self, handler, reader):
            """Check for file level code.

            Check for Python code that should go in the beginning of the generated module.

            <psp:file>
                import xyz
                print 'hi Mome!'
                def foo(): return 'foo'
            </psp:file>

            """
            OPEN_SCRIPT = '<psp:file>'
            CLOSE_SCRIPT = '</psp:file>'
            attrs = None
            if reader.Matches(OPEN_SCRIPT):
                reader.Advance(len(OPEN_SCRIPT))
                start = reader.Mark()
                try:
                    stop = reader.skipUntil(CLOSE_SCRIPT)
                    if stop is None:
                        raise 'Unterminated Script is %s block' % OPEN_SCRIPT
                except EOFError:
                    raise EOFError("Reached EOF while looking for ending script tag (%s)" % CLOSE_SCRIPT)
                handler.setTemplateInfo(self.tmplStart, self.tmplStop)
                handler.handleScriptFile(start, stop, attrs)
                return 1
            return 0

        checklist.append(checkScriptFile)

        def checkScriptClass(self, handler, reader):
            """Check for class level code.

            Check for Python code that should go in the class definition.

            <psp:class>
                def foo(self):
                    return self.dosomething()
            </psp:class>

            """
            OPEN_SCRIPT = '<psp:class>'
            CLOSE_SCRIPT = '</psp:class>'
            attrs = None
            if reader.Matches(OPEN_SCRIPT):
                reader.Advance(len(OPEN_SCRIPT))
                start = reader.Mark()
                try:
                    stop = reader.skipUntil(CLOSE_SCRIPT)
                    if stop is None:
                        raise 'Unterminated Script is %s block' % OPEN_SCRIPT
                except EOFError:
                    raise EOFError("Reached EOF while looking for ending script tag (%s)" % CLOSE_SCRIPT)
                handler.setTemplateInfo(self.tmplStart, self.tmplStop)
                handler.handleScriptClass(start, stop, attrs)
                return 1
            return 0

        checklist.append(checkScriptClass)

        def checkMethod(self, handler, reader):
            """Check for class methods defined in the page.

            I only support one format for these,
            <psp:method name="xxx" params="xxx,xxx">
            Then the function BODY, then <psp:method>.

            """
            OPEN_METHOD = '<psp:method'
            CLOSE_METHOD = '/>'
            CLOSE_METHOD_2 = '</psp:method>'
            CLOSE_METHOD_3 = '>'
            attrs = None
            validAttributes = ('name', 'params')
            if reader.Matches(OPEN_METHOD):
                start = reader.Mark()
                reader.Advance(len(OPEN_METHOD))
                attrs = reader.parseTagAttributes()
                # PSPUtils.checkAttributes('method',attrs,validAttributes)
                reader.skipSpaces()
                if not reader.Matches(CLOSE_METHOD_3):
                    raise 'Expected method declaration close'
                reader.Advance(len(CLOSE_METHOD_3))
                stop = reader.Mark()
                handler.setTemplateInfo(self.tmplStart, self.tmplStop)
                handler.handleMethod(start, stop, attrs)
                start = stop
                stop = reader.skipUntil(CLOSE_METHOD_2) #skip past the close marker, return the point before the close marker
                handler.handleMethodEnd(start, stop, attrs)
                return 1
            return 0

        checklist.append(checkMethod)

        def checkInclude(self, handler, reader):
            """Check for inserting another pages output in this spot."""
            OPEN_INCLUDE = '<psp:include'
            CLOSE_INCLUDE_NO_BODY = "/>"
            CLOSE_INCLUDE_BODY = ">"
            CLOSE_INCLUDE = "</psp:include>"
            OPEN_INDIVIDUAL_PARAM = "<psp:param"
            CLOSE_INDIVIDUAL_PARAM = "/>"
            if reader.Matches(OPEN_INCLUDE):
                param = {}
                start = reader.Mark()
                reader.Advance(len(OPEN_INCLUDE))
                reader.skipSpaces()
                attrs = reader.parseTagAttributes()
                #PSPUtils.checkTagAttributes()....
                reader.skipSpaces()
                if not reader.Matches(CLOSE_INCLUDE_BODY):
                    raise "Include bodies not implemented"
                reader.Advance(len(CLOSE_INCLUDE_BODY))
                stop = reader.Mark()
                handler.setTemplateInfo(self.tmplStart, self.tmplStop)
                handler.handleInclude(attrs, param)
                return 1
            return 0

        checklist.append(checkInclude)

        def checkInsert(self, handler, reader):
            """Check for straight character dumps.

            No big hurry for this. It's almost the same as the page include
            directive.  This is only a partial implementation of what JSP does.
            JSP can pull it from another server, servlet, JSP page, etc.

            """
            OPEN_INSERT = '<psp:insert'
            CLOSE_INSERT_NO_BODY = "/>"
            CLOSE_INSERT_BODY = ">"
            CLOSE_INSERT = "</psp:insert>"
            OPEN_INDIVIDUAL_PARAM = "<psp:param"
            CLOSE_INDIVIDUAL_PARAM = "/>"
            if reader.Matches(OPEN_INSERT):
                param = {}
                start = reader.Mark()
                reader.Advance(len(OPEN_INSERT))
                reader.skipSpaces()
                attrs = reader.parseTagAttributes()
                # PSPUtils.checkTagAttributes()....
                reader.skipSpaces()
                if not reader.Matches(CLOSE_INSERT_BODY):
                    raise "Insert bodies not implemented"
                reader.Advance(len(CLOSE_INSERT_BODY))
                stop = reader.Mark()
                handler.setTemplateInfo(self.tmplStart, self.tmplStop)
                handler.handleInsert(attrs, param)
                return 1
            return 0

        checklist.append(checkInsert)

        def parse(self, until=None, accept=None):
            """Parse the PSP file."""
            noPspElement = 0
            reader = self._reader
            handler = self._handler
            while reader.hasMoreInput():
                # This is for XML style blocks, which I'm not handling yet
                if until is not None and reader.Matches(until):
                    return
                #If the file the reader is working on has changed due to a push or pop,
                #flush any char data from the old file
                if not reader.Mark().getFile() == self.currentFile:
                    self.flushCharData(self.tmplStart, self.tmplStop)
                    self.currentFile = reader.Mark().getFile()
                    self.tmplStart = reader.Mark()
            # in JSP, this is an array of valid tag type to check for,
            # I'm not using it now, # and I don't think JSP does either
                if accept:
                    pass
                accepted = 0
                for checkfunc in self.checklist:
                    if checkfunc(self, handler, reader):
                        accepted = 1
                        noPspElement = 0
                        break
                if not accepted:
                    if not noPspElement:
                        self.tmplStart = reader.Mark()
                        noPspElement = 1
                    st = reader.nextContent() #skip till the next possible tag
                    self.tmplStop = reader.Mark() #mark the end of HTML data
                    self.cout.write(st) #write out the raw HTML data
                self.flushCharData(self.tmplStart, self.tmplStop) #dump remaining raw HTML