python-uncompyle6/uncompyle6/semantics/aligner.py

#  Copyright (c) 2018, 2022 by Rocky Bernstein
#
#  This program is free software: you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation, either version 3 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program.  If not, see <http://www.gnu.org/licenses/>.

import sys
from uncompyle6.semantics.pysource import (
    SourceWalker, SourceWalkerError, find_globals, ASSIGN_DOC_STRING, RETURN_NONE)

from spark_parser import DEFAULT_DEBUG as PARSER_DEFAULT_DEBUG
from uncompyle6 import IS_PYPY

class AligningWalker(SourceWalker, object):
    def __init__(self, version, out, scanner, showast=False,
                 debug_parser=PARSER_DEFAULT_DEBUG,
                 compile_mode='exec', is_pypy=False):
        SourceWalker.__init__(self, version, out, scanner, showast, debug_parser,
                              compile_mode, is_pypy)
        self.desired_line_number = 0
        self.current_line_number = 0

    def println(self, *data):
        if data and not(len(data) == 1 and data[0] == ''):
            self.write(*data)

        self.pending_newlines = max(self.pending_newlines, 1)

    def write(self, *data):
        if (len(data) == 1) and data[0] == self.indent:
            diff = max(self.pending_newlines,
                       self.desired_line_number - self.current_line_number)
            self.f.write('\n'*diff)
            self.current_line_number += diff
            self.pending_newlines = 0
        if (len(data) == 0) or (len(data) == 1 and data[0] == ''):
            return

        out = ''.join((str(j) for j in data))
        n = 0
        for i in out:
            if i == '\n':
                n += 1
                if n == len(out):
                    self.pending_newlines = max(self.pending_newlines, n)
                    return
            elif n:
                self.pending_newlines = max(self.pending_newlines, n)
                out = out[n:]
                break
            else:
                break

        if self.pending_newlines > 0:
            diff = max(self.pending_newlines,
                       self.desired_line_number - self.current_line_number)
            self.f.write('\n'*diff)
            self.current_line_number += diff
            self.pending_newlines = 0

        for i in out[::-1]:
            if i == '\n':
                self.pending_newlines += 1
            else:
                break

        if self.pending_newlines:
            out = out[:-self.pending_newlines]
        self.f.write(out)

    def default(self, node):
        mapping = self._get_mapping(node)
        if hasattr(node, 'linestart'):
            if node.linestart:
                self.desired_line_number = node.linestart
        table = mapping[0]
        key = node

        for i in mapping[1:]:
            key = key[i]
            pass

        if key.type in table:
            self.engine(table[key.type], node)
            self.prune()

from xdis import iscode
from uncompyle6.scanner import get_scanner
from uncompyle6.show import (
    maybe_show_asm,
)

#
DEFAULT_DEBUG_OPTS = {
    'asm': False,
    'tree': False,
    'grammar': False
}

def code_deparse_align(co, out=sys.stderr, version=None, is_pypy=None,
                       debug_opts=DEFAULT_DEBUG_OPTS,
                       code_objects={}, compile_mode='exec'):
    """
    ingests and deparses a given code block 'co'
    """

    assert iscode(co)

    if version is None:
        version = float(sys.version[0:3])
    if is_pypy is None:
        is_pypy = IS_PYPY


    # store final output stream for case of error
    scanner = get_scanner(version, is_pypy=is_pypy)

    tokens, customize = scanner.ingest(co, code_objects=code_objects)
    show_asm = debug_opts.get('asm', None)
    maybe_show_asm(show_asm, tokens)

    debug_parser = dict(PARSER_DEFAULT_DEBUG)
    show_grammar = debug_opts.get('grammar', None)
    show_grammar = debug_opts.get('grammar', None)
    if show_grammar:
        debug_parser['reduce'] = show_grammar
        debug_parser['errorstack'] = True

    #  Build a parse tree from tokenized and massaged disassembly.
    show_ast = debug_opts.get('ast', None)
    deparsed = AligningWalker(version, scanner, out, showast=show_ast,
                            debug_parser=debug_parser, compile_mode=compile_mode,
                            is_pypy = is_pypy)

    is_top_level_module = co.co_name == '<module>'
    deparsed.ast = deparsed.build_ast(tokens, customize, co, is_top_level_module=is_top_level_module)

    assert deparsed.ast == 'stmts', 'Should have parsed grammar start'

    del tokens # save memory

    deparsed.mod_globs = find_globals(deparsed.ast, set())

    # convert leading '__doc__ = "..." into doc string
    try:
        if deparsed.ast[0][0] == ASSIGN_DOC_STRING(co.co_consts[0]):
            deparsed.print_docstring('', co.co_consts[0])
            del deparsed.ast[0]
        if deparsed.ast[-1] == RETURN_NONE:
            deparsed.ast.pop() # remove last node
            # todo: if empty, add 'pass'
    except:
        pass

    # What we've been waiting for: Generate Python source from the parse tree!
    deparsed.gen_source(deparsed.ast, co.co_name, customize)

    for g in sorted(deparsed.mod_globs):
        deparsed.write('# global %s ## Warning: Unused global\n' % g)

    if deparsed.ERROR:
        raise SourceWalkerError("Deparsing stopped due to parse error")
    return deparsed

if __name__ == '__main__':
    def deparse_test(co):
        "This is a docstring"
        deparsed = code_deparse_align(co)
        print(deparsed.text)
        return
    deparse_test(deparse_test.__code__)