#!/usr/bin/env python

'''
Parse a C source file.

To use, subclass CParser and override its handle_* methods.  Then instantiate
the class with a string to parse.
'''

__docformat__ = 'restructuredtext'

import operator
import os.path
import re
import sys
import time
import warnings

import preprocessor
import yacc
import cgrammar
import cdeclarations

# --------------------------------------------------------------------------
# Lexer
# --------------------------------------------------------------------------

class CLexer(object):
    def __init__(self, cparser):
        self.cparser = cparser
        self.type_names = set()
        self.in_define = False

    def input(self, tokens):
        self.tokens = tokens
        self.pos = 0

    def token(self):
        while self.pos < len(self.tokens):
            t = self.tokens[self.pos]
            
            self.pos += 1

            if not t:
                break
            
            if t.type == 'PP_DEFINE':
                self.in_define = True
            elif t.type == 'PP_END_DEFINE':
                self.in_define = False
            
            # Transform PP tokens into C tokens
            elif t.type == 'LPAREN':
                t.type = '('
            elif t.type == 'PP_NUMBER':
                t.type = 'CONSTANT'
            elif t.type == 'IDENTIFIER' and t.value in cgrammar.keywords:
                t.type = t.value.upper()
            elif t.type == 'IDENTIFIER' and t.value in self.type_names:
                if (self.pos < 2 or self.tokens[self.pos-2].type not in
                    ('ENUM', 'STRUCT', 'UNION')):
                    t.type = 'TYPE_NAME'
            
            t.lexer = self
            t.clexpos = self.pos - 1
            
            return t
        return None
        
# --------------------------------------------------------------------------
# Parser
# --------------------------------------------------------------------------

class CParser(object):
    '''Parse a C source file.

    Subclass and override the handle_* methods.  Call `parse` with a string
    to parse.
    '''
    def __init__(self, options, stddef_types=True, gnu_types=True):
        self.preprocessor_parser = preprocessor.PreprocessorParser(options,self)
        self.parser = yacc.Parser()
        prototype = yacc.yacc(method        = 'LALR',
                              debug         = False,
                              module        = cgrammar,
                              write_tables  = True,
                              outputdir     = os.path.dirname(__file__),
                              optimize      = True)
        
        # If yacc is reading tables from a file, then it won't find the error
        # function... need to set it manually
        prototype.errorfunc = cgrammar.p_error
        prototype.init_parser(self.parser)
        self.parser.cparser = self

        self.lexer = CLexer(self)
        if stddef_types:
            self.lexer.type_names.add('wchar_t')
            self.lexer.type_names.add('ptrdiff_t')
            self.lexer.type_names.add('size_t')
        if gnu_types:
            self.lexer.type_names.add('__builtin_va_list')
        if sys.platform == 'win32':
            self.lexer.type_names.add('__int64')
        
    def parse(self, filename, debug=False):
        '''Parse a file.

        If `debug` is True, parsing state is dumped to stdout.
        '''

        self.handle_status('Preprocessing %s' % filename)
        self.preprocessor_parser.parse(filename)
        self.lexer.input(self.preprocessor_parser.output)
        self.handle_status('Parsing %s' % filename)
        self.parser.parse(lexer=self.lexer, debug=debug)

    # ----------------------------------------------------------------------
    # Parser interface.  Override these methods in your subclass.
    # ----------------------------------------------------------------------

    def handle_error(self, message, filename, lineno):
        '''A parse error occurred.  
        
        The default implementation prints `lineno` and `message` to stderr.
        The parser will try to recover from errors by synchronising at the
        next semicolon.
        '''
        print >> sys.stderr, '%s:%s %s' % (filename, lineno, message)
    
    def handle_pp_error(self, message):
        '''The C preprocessor emitted an error.
        
        The default implementatin prints the error to stderr. If processing
        can continue, it will.
        '''
        print >> sys.stderr, 'Preprocessor:', message
    
    def handle_status(self, message):
        '''Progress information.

        The default implementationg prints message to stderr.
        '''
        print >> sys.stderr, message

    def handle_define(self, name, params, value, filename, lineno):
        '''#define `name` `value` 
        or #define `name`(`params`) `value`

        name is a string
        params is None or a list of strings
        value is a ...?
        '''

    def handle_define_constant(self, name, value, filename, lineno):
        '''#define `name` `value`
        
        name is a string
        value is an ExpressionNode or None
        '''
    
    def handle_define_macro(self, name, params, value, filename, lineno):
        '''#define `name`(`params`) `value`
        
        name is a string
        params is a list of strings
        value is an ExpressionNode or None
        '''
    
    def impl_handle_declaration(self, declaration, filename, lineno):
        '''Internal method that calls `handle_declaration`.  This method
        also adds any new type definitions to the lexer's list of valid type
        names, which affects the parsing of subsequent declarations.
        '''
        if declaration.storage == 'typedef':
            declarator = declaration.declarator
            if not declarator:
                # XXX TEMPORARY while struct etc not filled
                return
            while declarator.pointer:
                declarator = declarator.pointer
            self.lexer.type_names.add(declarator.identifier)
        self.handle_declaration(declaration, filename, lineno)

    def handle_declaration(self, declaration, filename, lineno):
        '''A declaration was encountered.  
        
        `declaration` is an instance of Declaration.  Where a declaration has
        multiple initialisers, each is returned as a separate declaration.
        '''
        pass

class DebugCParser(CParser):
    '''A convenience class that prints each invocation of a handle_* method to
    stdout.
    '''

    def handle_define(self, name, value, filename, lineno):
        print '#define name=%r, value=%r' % (name, value)

    def handle_define_constant(self, name, value, filename, lineno):
        print '#define constant name=%r, value=%r' % (name, value)

    def handle_declaration(self, declaration, filename, lineno):
        print declaration
        
if __name__ == '__main__':
    DebugCParser().parse(sys.argv[1], debug=True)
