mirror of
https://github.com/davidhalter/parso.git
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586 lines
22 KiB
Python
586 lines
22 KiB
Python
"""
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Basically a contains parser that is faster, because it tries to parse only
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parts and if anything changes, it only reparses the changed parts.
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It works with a simple diff in the beginning and will try to reuse old parser
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fragments.
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"""
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import re
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import difflib
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from collections import namedtuple
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import logging
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from parso.utils import splitlines
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from parso.python.parser import Parser
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from parso.python.tree import EndMarker
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from parso.python.tokenize import (tokenize_lines, NEWLINE, TokenInfo,
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ENDMARKER, INDENT, DEDENT, ERRORTOKEN)
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def _get_last_line(node_or_leaf):
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last_leaf = node_or_leaf.get_last_leaf()
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if _ends_with_newline(last_leaf):
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return last_leaf.start_pos[0]
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else:
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return last_leaf.end_pos[0]
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def _ends_with_newline(leaf, suffix=''):
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if leaf.type == 'error_leaf':
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typ = leaf.original_type
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else:
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typ = leaf.type
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return typ == 'newline' or suffix.endswith('\n')
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def _flows_finished(pgen_grammar, stack):
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"""
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if, while, for and try might not be finished, because another part might
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still be parsed.
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"""
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for dfa, newstate, (symbol_number, nodes) in stack:
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if pgen_grammar.number2symbol[symbol_number] in ('if_stmt', 'while_stmt',
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'for_stmt', 'try_stmt'):
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return False
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return True
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def suite_or_file_input_is_valid(pgen_grammar, stack):
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if not _flows_finished(pgen_grammar, stack):
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return False
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for dfa, newstate, (symbol_number, nodes) in reversed(stack):
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if pgen_grammar.number2symbol[symbol_number] == 'suite':
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# If only newline is in the suite, the suite is not valid, yet.
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return len(nodes) > 1
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# Not reaching a suite means that we're dealing with file_input levels
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# where there's no need for a valid statement in it. It can also be empty.
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return True
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def _is_flow_node(node):
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try:
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value = node.children[0].value
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except AttributeError:
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return False
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return value in ('if', 'for', 'while', 'try')
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class _PositionUpdatingFinished(Exception):
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pass
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def _update_positions(nodes, line_offset, last_leaf):
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for node in nodes:
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try:
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children = node.children
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except AttributeError:
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# Is a leaf
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node.line += line_offset
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if node is last_leaf:
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raise _PositionUpdatingFinished
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else:
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_update_positions(children, line_offset, last_leaf)
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class DiffParser(object):
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"""
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An advanced form of parsing a file faster. Unfortunately comes with huge
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side effects. It changes the given module.
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"""
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def __init__(self, pgen_grammar, module):
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self._pgen_grammar = pgen_grammar
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self._module = module
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def _reset(self):
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self._copy_count = 0
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self._parser_count = 0
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self._nodes_stack = _NodesStack(self._module)
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def update(self, old_lines, new_lines):
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'''
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The algorithm works as follows:
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Equal:
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- Assure that the start is a newline, otherwise parse until we get
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one.
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- Copy from parsed_until_line + 1 to max(i2 + 1)
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- Make sure that the indentation is correct (e.g. add DEDENT)
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- Add old and change positions
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Insert:
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- Parse from parsed_until_line + 1 to min(j2 + 1), hopefully not
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much more.
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Returns the new module node.
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'''
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logging.debug('diff parser start')
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# Reset the used names cache so they get regenerated.
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self._module._used_names = None
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self._parser_lines_new = new_lines
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self._reset()
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line_length = len(new_lines)
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sm = difflib.SequenceMatcher(None, old_lines, self._parser_lines_new)
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opcodes = sm.get_opcodes()
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logging.debug('diff parser calculated')
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logging.debug('diff: line_lengths old: %s, new: %s' % (len(old_lines), line_length))
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for operation, i1, i2, j1, j2 in opcodes:
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logging.debug('diff %s old[%s:%s] new[%s:%s]',
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operation, i1 + 1, i2, j1 + 1, j2)
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if j2 == line_length and new_lines[-1] == '':
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# The empty part after the last newline is not relevant.
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j2 -= 1
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if operation == 'equal':
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line_offset = j1 - i1
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self._copy_from_old_parser(line_offset, i2, j2)
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elif operation == 'replace':
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self._parse(until_line=j2)
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elif operation == 'insert':
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self._parse(until_line=j2)
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else:
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assert operation == 'delete'
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# With this action all change will finally be applied and we have a
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# changed module.
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self._nodes_stack.close()
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last_pos = self._module.end_pos[0]
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if last_pos != line_length:
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current_lines = splitlines(self._module.get_code(), keepends=True)
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diff = difflib.unified_diff(current_lines, new_lines)
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raise Exception(
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"There's an issue (%s != %s) with the diff parser. Please report:\n%s"
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% (last_pos, line_length, ''.join(diff))
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)
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logging.debug('diff parser end')
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return self._module
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def _enabled_debugging(self, old_lines, lines_new):
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if self._module.get_code() != ''.join(lines_new):
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logging.warning('parser issue:\n%s\n%s', ''.join(old_lines),
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''.join(lines_new))
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def _copy_from_old_parser(self, line_offset, until_line_old, until_line_new):
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copied_nodes = [None]
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last_until_line = -1
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while until_line_new > self._nodes_stack.parsed_until_line:
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parsed_until_line_old = self._nodes_stack.parsed_until_line - line_offset
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line_stmt = self._get_old_line_stmt(parsed_until_line_old + 1)
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if line_stmt is None:
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# Parse 1 line at least. We don't need more, because we just
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# want to get into a state where the old parser has statements
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# again that can be copied (e.g. not lines within parentheses).
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self._parse(self._nodes_stack.parsed_until_line + 1)
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elif not copied_nodes:
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# We have copied as much as possible (but definitely not too
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# much). Therefore we just parse the rest.
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# We might not reach the end, because there's a statement
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# that is not finished.
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self._parse(until_line_new)
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else:
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p_children = line_stmt.parent.children
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index = p_children.index(line_stmt)
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copied_nodes = self._nodes_stack.copy_nodes(
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p_children[index:],
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until_line_old,
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line_offset
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)
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# Match all the nodes that are in the wanted range.
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if copied_nodes:
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self._copy_count += 1
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from_ = copied_nodes[0].get_start_pos_of_prefix()[0] + line_offset
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to = self._nodes_stack.parsed_until_line
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logging.debug('diff actually copy %s to %s', from_, to)
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# Since there are potential bugs that might loop here endlessly, we
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# just stop here.
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assert last_until_line != self._nodes_stack.parsed_until_line \
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or not copied_nodes, last_until_line
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last_until_line = self._nodes_stack.parsed_until_line
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def _get_old_line_stmt(self, old_line):
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leaf = self._module.get_leaf_for_position((old_line, 0), include_prefixes=True)
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if _ends_with_newline(leaf):
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leaf = leaf.get_next_leaf()
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if leaf.get_start_pos_of_prefix()[0] == old_line:
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node = leaf
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while node.parent.type not in ('file_input', 'suite'):
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node = node.parent
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return node
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# Must be on the same line. Otherwise we need to parse that bit.
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return None
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def _get_before_insertion_node(self):
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if self._nodes_stack.is_empty():
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return None
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line = self._nodes_stack.parsed_until_line + 1
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node = self._new_module.get_last_leaf()
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while True:
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parent = node.parent
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if parent.type in ('suite', 'file_input'):
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assert node.end_pos[0] <= line
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assert node.end_pos[1] == 0 or '\n' in self._prefix
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return node
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node = parent
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def _parse(self, until_line):
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"""
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Parses at least until the given line, but might just parse more until a
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valid state is reached.
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"""
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last_until_line = 0
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while until_line > self._nodes_stack.parsed_until_line:
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node = self._try_parse_part(until_line)
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nodes = node.children
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self._nodes_stack.add_parsed_nodes(nodes)
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logging.debug(
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'parse_part from %s to %s (to %s in part parser)',
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nodes[0].get_start_pos_of_prefix()[0],
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self._nodes_stack.parsed_until_line,
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node.end_pos[0] - 1
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)
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# Since the tokenizer sometimes has bugs, we cannot be sure that
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# this loop terminates. Therefore assert that there's always a
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# change.
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assert last_until_line != self._nodes_stack.parsed_until_line, last_until_line
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last_until_line = self._nodes_stack.parsed_until_line
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def _try_parse_part(self, until_line):
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"""
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Sets up a normal parser that uses a spezialized tokenizer to only parse
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until a certain position (or a bit longer if the statement hasn't
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ended.
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"""
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self._parser_count += 1
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# TODO speed up, shouldn't copy the whole list all the time.
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# memoryview?
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parsed_until_line = self._nodes_stack.parsed_until_line
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lines_after = self._parser_lines_new[parsed_until_line:]
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#print('parse_content', parsed_until_line, lines_after, until_line)
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tokens = self._diff_tokenize(
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lines_after,
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until_line,
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line_offset=parsed_until_line
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)
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self._active_parser = Parser(
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self._pgen_grammar,
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error_recovery=True
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)
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return self._active_parser.parse(tokens=tokens)
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def _diff_tokenize(self, lines, until_line, line_offset=0):
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is_first_token = True
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omitted_first_indent = False
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indents = []
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tokens = tokenize_lines(lines)
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stack = self._active_parser.pgen_parser.stack
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for typ, string, start_pos, prefix in tokens:
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start_pos = start_pos[0] + line_offset, start_pos[1]
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if typ == INDENT:
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indents.append(start_pos[1])
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if is_first_token:
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omitted_first_indent = True
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# We want to get rid of indents that are only here because
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# we only parse part of the file. These indents would only
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# get parsed as error leafs, which doesn't make any sense.
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is_first_token = False
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continue
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is_first_token = False
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# In case of omitted_first_indent, it might not be dedented fully.
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# However this is a sign for us that a dedent happened.
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if typ == DEDENT \
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or typ == ERRORTOKEN and not string \
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and omitted_first_indent and len(indents) == 1:
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indents.pop()
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if omitted_first_indent and not indents:
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# We are done here, only thing that can come now is an
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# endmarker or another dedented code block.
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typ, string, start_pos, prefix = next(tokens)
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if '\n' in prefix:
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prefix = re.sub(r'(<=\n)[^\n]+$', '', prefix)
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else:
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prefix = ''
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yield TokenInfo(ENDMARKER, '', (start_pos[0] + line_offset, 0), prefix)
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break
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elif typ == NEWLINE and start_pos[0] >= until_line:
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yield TokenInfo(typ, string, start_pos, prefix)
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# Check if the parser is actually in a valid suite state.
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if suite_or_file_input_is_valid(self._pgen_grammar, stack):
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start_pos = start_pos[0] + 1, 0
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while len(indents) > int(omitted_first_indent):
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indents.pop()
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yield TokenInfo(DEDENT, '', start_pos, '')
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yield TokenInfo(ENDMARKER, '', start_pos, '')
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break
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else:
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continue
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yield TokenInfo(typ, string, start_pos, prefix)
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class _NodesStackNode(object):
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ChildrenGroup = namedtuple('ChildrenGroup', 'children line_offset last_line_offset_leaf')
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def __init__(self, tree_node, parent=None):
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self.tree_node = tree_node
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self.children_groups = []
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self.parent = parent
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def close(self):
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children = []
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for children_part, line_offset, last_line_offset_leaf in self.children_groups:
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if line_offset != 0:
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try:
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_update_positions(
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children_part, line_offset, last_line_offset_leaf)
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except _PositionUpdatingFinished:
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pass
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children += children_part
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self.tree_node.children = children
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# Reset the parents
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for node in children:
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node.parent = self.tree_node
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def add(self, children, line_offset=0, last_line_offset_leaf=None):
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group = self.ChildrenGroup(children, line_offset, last_line_offset_leaf)
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self.children_groups.append(group)
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def get_last_line(self, suffix):
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line = 0
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if self.children_groups:
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children_group = self.children_groups[-1]
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last_leaf = children_group.children[-1].get_last_leaf()
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line = last_leaf.end_pos[0]
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# Calculate the line offsets
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offset = children_group.line_offset
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if offset:
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# In case the line_offset is not applied to this specific leaf,
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# just ignore it.
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if last_leaf.line <= children_group.last_line_offset_leaf.line:
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line += children_group.line_offset
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# Newlines end on the next line, which means that they would cover
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# the next line. That line is not fully parsed at this point.
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if _ends_with_newline(last_leaf, suffix):
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line -= 1
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line += suffix.count('\n')
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if suffix and not suffix.endswith('\n'):
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# This is the end of a file (that doesn't end with a newline).
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line += 1
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return line
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class _NodesStack(object):
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endmarker_type = 'endmarker'
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def __init__(self, module):
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# Top of stack
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self._tos = self._base_node = _NodesStackNode(module)
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self._module = module
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self._last_prefix = ''
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self.prefix = ''
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def is_empty(self):
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return not self._base_node.children
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@property
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def parsed_until_line(self):
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return self._tos.get_last_line(self.prefix)
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def _get_insertion_node(self, indentation_node):
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indentation = indentation_node.start_pos[1]
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# find insertion node
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node = self._tos
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while True:
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tree_node = node.tree_node
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if tree_node.type == 'suite':
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# A suite starts with NEWLINE, ...
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node_indentation = tree_node.children[1].start_pos[1]
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if indentation >= node_indentation: # Not a Dedent
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# We might be at the most outer layer: modules. We
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# don't want to depend on the first statement
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# having the right indentation.
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return node
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elif tree_node.type == 'file_input':
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return node
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node = self._close_tos()
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def _close_tos(self):
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self._tos.close()
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self._tos = self._tos.parent
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return self._tos
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def add_parsed_nodes(self, tree_nodes):
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tree_nodes = self._remove_endmarker(tree_nodes)
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if not tree_nodes:
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return
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assert tree_nodes[0].type != 'newline'
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node = self._get_insertion_node(tree_nodes[0])
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assert node.tree_node.type in ('suite', 'file_input')
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node.add(tree_nodes)
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self._update_tos(tree_nodes[-1])
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def _remove_endmarker(self, tree_nodes):
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"""
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Helps cleaning up the tree nodes that get inserted.
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"""
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last_leaf = tree_nodes[-1].get_last_leaf()
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is_endmarker = last_leaf.type == self.endmarker_type
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self._last_prefix = ''
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if is_endmarker:
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try:
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separation = last_leaf.prefix.rindex('\n')
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except ValueError:
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pass
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else:
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# Remove the whitespace part of the prefix after a newline.
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# That is not relevant if parentheses were opened. Always parse
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# until the end of a line.
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last_leaf.prefix, self._last_prefix = \
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last_leaf.prefix[:separation + 1], last_leaf.prefix[separation + 1:]
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first_leaf = tree_nodes[0].get_first_leaf()
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first_leaf.prefix = self.prefix + first_leaf.prefix
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self.prefix = ''
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if is_endmarker:
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self.prefix = last_leaf.prefix
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tree_nodes = tree_nodes[:-1]
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return tree_nodes
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def copy_nodes(self, tree_nodes, until_line, line_offset):
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"""
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Copies tree nodes from the old parser tree.
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Returns the number of tree nodes that were copied.
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"""
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tos = self._get_insertion_node(tree_nodes[0])
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new_nodes, self._tos = self._copy_nodes(tos, tree_nodes, until_line, line_offset)
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return new_nodes
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def _copy_nodes(self, tos, nodes, until_line, line_offset):
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new_nodes = []
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new_tos = tos
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for node in nodes:
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if node.type == 'endmarker':
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# Endmarkers just distort all the checks below. Remove them.
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break
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if node.start_pos[0] > until_line:
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break
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# TODO this check might take a bit of time for large files. We
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# might want to change this to do more intelligent guessing or
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# binary search.
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if _get_last_line(node) > until_line:
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# We can split up functions and classes later.
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if node.type in ('classdef', 'funcdef') and node.children[-1].type == 'suite':
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|
new_nodes.append(node)
|
|
break
|
|
|
|
new_nodes.append(node)
|
|
|
|
if not new_nodes:
|
|
return [], tos
|
|
|
|
last_node = new_nodes[-1]
|
|
line_offset_index = -1
|
|
if last_node.type in ('classdef', 'funcdef'):
|
|
suite = last_node.children[-1]
|
|
if suite.type == 'suite':
|
|
suite_tos = _NodesStackNode(suite)
|
|
# Don't need to pass line_offset here, it's already done by the
|
|
# parent.
|
|
suite_nodes, recursive_tos = self._copy_nodes(
|
|
suite_tos, suite.children, until_line, line_offset)
|
|
if len(suite_nodes) < 2:
|
|
# A suite only with newline is not valid.
|
|
new_nodes.pop()
|
|
else:
|
|
suite_tos.parent = tos
|
|
new_tos = recursive_tos
|
|
line_offset_index = -2
|
|
|
|
elif (new_nodes[-1].type in ('error_leaf', 'error_node') or
|
|
_is_flow_node(new_nodes[-1])):
|
|
# Error leafs/nodes don't have a defined start/end. Error
|
|
# nodes might not end with a newline (e.g. if there's an
|
|
# open `(`). Therefore ignore all of them unless they are
|
|
# succeeded with valid parser state.
|
|
# If we copy flows at the end, they might be continued
|
|
# after the copy limit (in the new parser).
|
|
# In this while loop we try to remove until we find a newline.
|
|
new_nodes.pop()
|
|
while new_nodes:
|
|
last_node = new_nodes[-1]
|
|
if last_node.get_last_leaf().type == 'newline':
|
|
break
|
|
new_nodes.pop()
|
|
|
|
if new_nodes:
|
|
try:
|
|
last_line_offset_leaf = new_nodes[line_offset_index].get_last_leaf()
|
|
except IndexError:
|
|
line_offset = 0
|
|
# In this case we don't have to calculate an offset, because
|
|
# there's no children to be managed.
|
|
last_line_offset_leaf = None
|
|
tos.add(new_nodes, line_offset, last_line_offset_leaf)
|
|
return new_nodes, new_tos
|
|
|
|
def _update_tos(self, tree_node):
|
|
if tree_node.type in ('suite', 'file_input'):
|
|
self._tos = _NodesStackNode(tree_node, self._tos)
|
|
self._tos.add(list(tree_node.children))
|
|
self._update_tos(tree_node.children[-1])
|
|
elif tree_node.type in ('classdef', 'funcdef'):
|
|
self._update_tos(tree_node.children[-1])
|
|
|
|
def close(self):
|
|
while self._tos is not None:
|
|
self._close_tos()
|
|
|
|
# Add an endmarker.
|
|
try:
|
|
last_leaf = self._module.get_last_leaf()
|
|
end_pos = list(last_leaf.end_pos)
|
|
except IndexError:
|
|
end_pos = [1, 0]
|
|
lines = splitlines(self.prefix)
|
|
assert len(lines) > 0
|
|
if len(lines) == 1:
|
|
end_pos[1] += len(lines[0])
|
|
else:
|
|
end_pos[0] += len(lines) - 1
|
|
end_pos[1] = len(lines[-1])
|
|
|
|
endmarker = EndMarker('', tuple(end_pos), self.prefix + self._last_prefix)
|
|
endmarker.parent = self._module
|
|
self._module.children.append(endmarker)
|