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yapf/yapf/yapflib/yapf_api.py

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# Copyright 2015 Google Inc. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Entry points for YAPF.
The main APIs that YAPF exposes to drive the reformatting.
FormatFile(): reformat a file.
FormatCode(): reformat a string of code.
These APIs have some common arguments:
style_config: (string) Either a style name or a path to a file that contains
formatting style settings. If None is specified, use the default style
as set in style.DEFAULT_STYLE_FACTORY
lines: (list of tuples of integers) A list of tuples of lines, [start, end],
that we want to format. The lines are 1-based indexed. It can be used by
third-party code (e.g., IDEs) when reformatting a snippet of code rather
than a whole file.
print_diff: (bool) Instead of returning the reformatted source, return a
diff that turns the formatted source into reformatter source.
verify: (bool) True if reformatted code should be verified for syntax.
"""
import difflib
import re
import sys
from yapf.pytree import pytree_unwrapper
from yapf.pytree import pytree_utils
from yapf.pytree import blank_line_calculator
from yapf.pytree import comment_splicer
from yapf.pytree import continuation_splicer
from yapf.pytree import split_penalty
from yapf.pytree import subtype_assigner
from yapf.yapflib import errors
from yapf.yapflib import file_resources
from yapf.yapflib import identify_container
from yapf.yapflib import py3compat
from yapf.yapflib import reformatter
from yapf.yapflib import style
def FormatFile(filename,
style_config=None,
lines=None,
print_diff=False,
verify=False,
in_place=False,
logger=None):
"""Format a single Python file and return the formatted code.
Arguments:
filename: (unicode) The file to reformat.
style_config: (string) Either a style name or a path to a file that contains
formatting style settings. If None is specified, use the default style
as set in style.DEFAULT_STYLE_FACTORY
lines: (list of tuples of integers) A list of tuples of lines, [start, end],
that we want to format. The lines are 1-based indexed. It can be used by
third-party code (e.g., IDEs) when reformatting a snippet of code rather
than a whole file.
print_diff: (bool) Instead of returning the reformatted source, return a
diff that turns the formatted source into reformatter source.
verify: (bool) True if reformatted code should be verified for syntax.
in_place: (bool) If True, write the reformatted code back to the file.
logger: (io streamer) A stream to output logging.
Returns:
Tuple of (reformatted_code, encoding, changed). reformatted_code is None if
the file is successfully written to (having used in_place). reformatted_code
is a diff if print_diff is True.
Raises:
IOError: raised if there was an error reading the file.
ValueError: raised if in_place and print_diff are both specified.
"""
_CheckPythonVersion()
if in_place and print_diff:
raise ValueError('Cannot pass both in_place and print_diff.')
original_source, newline, encoding = ReadFile(filename, logger)
reformatted_source, changed = FormatCode(
original_source,
style_config=style_config,
filename=filename,
lines=lines,
print_diff=print_diff,
verify=verify)
if reformatted_source.rstrip('\n'):
lines = reformatted_source.rstrip('\n').split('\n')
reformatted_source = newline.join(iter(lines)) + newline
if in_place:
if original_source and original_source != reformatted_source:
file_resources.WriteReformattedCode(filename, reformatted_source,
encoding, in_place)
return None, encoding, changed
return reformatted_source, encoding, changed
def FormatTree(tree, style_config=None, lines=None, verify=False):
"""Format a parsed lib2to3 pytree.
This provides an alternative entry point to YAPF.
Arguments:
tree: (pytree.Node) The root of the pytree to format.
style_config: (string) Either a style name or a path to a file that contains
formatting style settings. If None is specified, use the default style
as set in style.DEFAULT_STYLE_FACTORY
lines: (list of tuples of integers) A list of tuples of lines, [start, end],
that we want to format. The lines are 1-based indexed. It can be used by
third-party code (e.g., IDEs) when reformatting a snippet of code rather
than a whole file.
verify: (bool) True if reformatted code should be verified for syntax.
Returns:
The source formatted according to the given formatting style.
"""
_CheckPythonVersion()
style.SetGlobalStyle(style.CreateStyleFromConfig(style_config))
# Run passes on the tree, modifying it in place.
comment_splicer.SpliceComments(tree)
continuation_splicer.SpliceContinuations(tree)
subtype_assigner.AssignSubtypes(tree)
identify_container.IdentifyContainers(tree)
split_penalty.ComputeSplitPenalties(tree)
blank_line_calculator.CalculateBlankLines(tree)
llines = pytree_unwrapper.UnwrapPyTree(tree)
for lline in llines:
lline.CalculateFormattingInformation()
lines = _LineRangesToSet(lines)
_MarkLinesToFormat(llines, lines)
return reformatter.Reformat(_SplitSemicolons(llines), verify, lines)
def FormatCode(unformatted_source,
filename='<unknown>',
style_config=None,
lines=None,
print_diff=False,
verify=False):
"""Format a string of Python code.
This provides an alternative entry point to YAPF.
Arguments:
unformatted_source: (unicode) The code to format.
filename: (unicode) The name of the file being reformatted.
style_config: (string) Either a style name or a path to a file that contains
formatting style settings. If None is specified, use the default style
as set in style.DEFAULT_STYLE_FACTORY
lines: (list of tuples of integers) A list of tuples of lines, [start, end],
that we want to format. The lines are 1-based indexed. It can be used by
third-party code (e.g., IDEs) when reformatting a snippet of code rather
than a whole file.
print_diff: (bool) Instead of returning the reformatted source, return a
diff that turns the formatted source into reformatter source.
verify: (bool) True if reformatted code should be verified for syntax.
Returns:
Tuple of (reformatted_source, changed). reformatted_source conforms to the
desired formatting style. changed is True if the source changed.
"""
try:
tree = pytree_utils.ParseCodeToTree(unformatted_source)
except Exception as e:
e.filename = filename
raise errors.YapfError(errors.FormatErrorMsg(e))
reformatted_source = FormatTree(
tree, style_config=style_config, lines=lines, verify=verify)
if unformatted_source == reformatted_source:
return '' if print_diff else reformatted_source, False
code_diff = _GetUnifiedDiff(
unformatted_source, reformatted_source, filename=filename)
if print_diff:
return code_diff, code_diff.strip() != '' # pylint: disable=g-explicit-bool-comparison # noqa
return reformatted_source, True
def _CheckPythonVersion(): # pragma: no cover
errmsg = 'yapf is only supported for Python 2.7 or 3.6+'
if sys.version_info[0] == 2:
if sys.version_info[1] < 7:
raise RuntimeError(errmsg)
elif sys.version_info[0] == 3:
if sys.version_info[1] < 6:
raise RuntimeError(errmsg)
def ReadFile(filename, logger=None):
"""Read the contents of the file.
An optional logger can be specified to emit messages to your favorite logging
stream. If specified, then no exception is raised. This is external so that it
can be used by third-party applications.
Arguments:
filename: (unicode) The name of the file.
logger: (function) A function or lambda that takes a string and emits it.
Returns:
The contents of filename.
Raises:
IOError: raised if there was an error reading the file.
"""
try:
encoding = file_resources.FileEncoding(filename)
# Preserves line endings.
with py3compat.open_with_encoding(
filename, mode='r', encoding=encoding, newline='') as fd:
lines = fd.readlines()
line_ending = file_resources.LineEnding(lines)
source = '\n'.join(line.rstrip('\r\n') for line in lines) + '\n'
return source, line_ending, encoding
except IOError as e: # pragma: no cover
if logger:
logger(e)
e.args = (e.args[0], (filename, e.args[1][1], e.args[1][2], e.args[1][3]))
raise
except UnicodeDecodeError as e: # pragma: no cover
if logger:
logger('Could not parse %s! Consider excluding this file with --exclude.',
filename)
logger(e)
e.args = (e.args[0], (filename, e.args[1][1], e.args[1][2], e.args[1][3]))
raise
def _SplitSemicolons(lines):
res = []
for line in lines:
res.extend(line.Split())
return res
DISABLE_PATTERN = r'^#.*\byapf:\s*disable\b'
ENABLE_PATTERN = r'^#.*\byapf:\s*enable\b'
def _LineRangesToSet(line_ranges):
"""Return a set of lines in the range."""
if line_ranges is None:
return None
line_set = set()
for low, high in sorted(line_ranges):
line_set.update(range(low, high + 1))
return line_set
def _MarkLinesToFormat(llines, lines):
"""Skip sections of code that we shouldn't reformat."""
if lines:
for uwline in llines:
uwline.disable = not lines.intersection(
range(uwline.lineno, uwline.last.lineno + 1))
# Now go through the lines and disable any lines explicitly marked as
# disabled.
index = 0
while index < len(llines):
uwline = llines[index]
if uwline.is_comment:
if _DisableYAPF(uwline.first.value.strip()):
index += 1
while index < len(llines):
uwline = llines[index]
line = uwline.first.value.strip()
if uwline.is_comment and _EnableYAPF(line):
if not _DisableYAPF(line):
break
uwline.disable = True
index += 1
elif re.search(DISABLE_PATTERN, uwline.last.value.strip(), re.IGNORECASE):
uwline.disable = True
index += 1
def _DisableYAPF(line):
return (re.search(DISABLE_PATTERN,
line.split('\n')[0].strip(), re.IGNORECASE) or
re.search(DISABLE_PATTERN,
line.split('\n')[-1].strip(), re.IGNORECASE))
def _EnableYAPF(line):
return (re.search(ENABLE_PATTERN,
line.split('\n')[0].strip(), re.IGNORECASE) or
re.search(ENABLE_PATTERN,
line.split('\n')[-1].strip(), re.IGNORECASE))
def _GetUnifiedDiff(before, after, filename='code'):
"""Get a unified diff of the changes.
Arguments:
before: (unicode) The original source code.
after: (unicode) The reformatted source code.
filename: (unicode) The code's filename.
Returns:
The unified diff text.
"""
before = before.splitlines()
after = after.splitlines()
return '\n'.join(
difflib.unified_diff(
before,
after,
filename,
filename,
'(original)',
'(reformatted)',
lineterm='')) + '\n'