text: # Copyright 2020 The Pigweed Authors
  #
  # 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
  #
  #     https://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.
  """Tools for running presubmit checks in a Git repository.
  
  Presubmit checks are defined as a function or other callable. The function may
  take either no arguments or a list of the paths on which to run. Presubmit
  checks communicate failure by raising any exception.
  
  For example, either of these functions may be used as presubmit checks:
  
    @pw_presubmit.filter_paths(endswith='.py')
    def file_contains_ni(ctx: PresubmitContext):
        for path in ctx.paths:
            with open(path) as file:
                contents = file.read()
                if 'ni' not in contents and 'nee' not in contents:
                    raise PresumitFailure('Files must say "ni"!', path=path)
  
    def run_the_build():
        subprocess.run(['make', 'release'], check=True)
  
  Presubmit checks that accept a list of paths may use the filter_paths decorator
  to automatically filter the paths list for file types they care about. See the
  pragma_once function for an example.
  
  See pigweed_presbumit.py for an example of how to define presubmit checks.
  """
  
  import collections
  import contextlib
  import dataclasses
  import enum
  from inspect import Parameter, signature
  import itertools
  import logging
  import os
  from pathlib import Path
  import re
  import subprocess
  import time
  from typing import (Callable, Collection, Dict, Iterable, Iterator, List,
                      NamedTuple, Optional, Pattern, Sequence, Set, Tuple, Union)
  
  from pw_presubmit import git_repo, tools
  from pw_presubmit.tools import plural
  
  _LOG: logging.Logger = logging.getLogger(__name__)
  
  color_red = tools.make_color(31)
  color_bold_red = tools.make_color(31, 1)
  color_black_on_red = tools.make_color(30, 41)
  color_yellow = tools.make_color(33, 1)
  color_green = tools.make_color(32)
  color_black_on_green = tools.make_color(30, 42)
  color_aqua = tools.make_color(36)
  color_bold_white = tools.make_color(37, 1)
  
  _SUMMARY_BOX = '══╦╗ ║║══╩╝'
  _CHECK_UPPER = '━━━┓       '
  _CHECK_LOWER = '       ━━━┛'
  
  WIDTH = 80
  
  _LEFT = 7
  _RIGHT = 11
  
  
  def _title(msg, style=_SUMMARY_BOX) -> str:
      msg = f' {msg} '.center(WIDTH - 2)
      return tools.make_box('^').format(*style, section1=msg, width1=len(msg))
  
  
  def _format_time(time_s: float) -> str:
      minutes, seconds = divmod(time_s, 60)
      if minutes < 60:
          return f' {int(minutes)}:{seconds:04.1f}'
      hours, minutes = divmod(minutes, 60)
      return f'{int(hours):d}:{int(minutes):02}:{int(seconds):02}'
  
  
  def _box(style, left, middle, right, box=tools.make_box('><>')) -> str:
      return box.format(*style,
                        section1=left + ('' if left.endswith(' ') else ' '),
                        width1=_LEFT,
                        section2=' ' + middle,
                        width2=WIDTH - _LEFT - _RIGHT - 4,
                        section3=right + ' ',
                        width3=_RIGHT)
  
  
  class PresubmitFailure(Exception):
      """Optional exception to use for presubmit failures."""
      def __init__(self, description: str = '', path=None):
          super().__init__(f'{path}: {description}' if path else description)
  
  
  class _Result(enum.Enum):
  
      PASS = 'PASSED'  # Check completed successfully.
      FAIL = 'FAILED'  # Check failed.
      CANCEL = 'CANCEL'  # Check didn't complete.
  
      def colorized(self, width: int, invert: bool = False) -> str:
          if self is _Result.PASS:
              color = color_black_on_green if invert else color_green
          elif self is _Result.FAIL:
              color = color_black_on_red if invert else color_red
          elif self is _Result.CANCEL:
              color = color_yellow
          else:
              color = lambda value: value
  
          padding = (width - len(self.value)) // 2 * ' '
          return padding + color(self.value) + padding
  
  
  class Program(collections.abc.Sequence):
      """A sequence of presubmit checks; basically a tuple with a name."""
      def __init__(self, name: str, steps: Iterable[Callable]):
          self.name = name
          self._steps = tuple(tools.flatten(steps))
  
      def __getitem__(self, i):
          return self._steps[i]
  
      def __len__(self):
          return len(self._steps)
  
      def __str__(self):
          return self.name
  
      def title(self):
          return f'{self.name if self.name else ""} presubmit checks'.strip()
  
  
  class Programs(collections.abc.Mapping):
      """A mapping of presubmit check programs.
  
      Use is optional. Helpful when managing multiple presubmit check programs.
      """
      def __init__(self, **programs: Sequence):
          """Initializes a name: program mapping from the provided keyword args.
  
          A program is a sequence of presubmit check functions. The sequence may
          contain nested sequences, which are flattened.
          """
          self._programs: Dict[str, Program] = {
              name: Program(name, checks)
              for name, checks in programs.items()
          }
  
      def all_steps(self) -> Dict[str, Callable]:
          return {c.__name__: c for c in itertools.chain(*self.values())}
  
      def __getitem__(self, item: str) -> Program:
          return self._programs[item]
  
      def __iter__(self) -> Iterator[str]:
          return iter(self._programs)
  
      def __len__(self) -> int:
          return len(self._programs)
  
  
  @dataclasses.dataclass(frozen=True)
  class PresubmitContext:
      """Context passed into presubmit checks."""
      root: Path
      repos: Tuple[Path, ...]
      output_dir: Path
      paths: Tuple[Path, ...]
      package_root: Path
  
      def relative_paths(self, start: Optional[Path] = None) -> Tuple[Path, ...]:
          return tuple(
              tools.relative_paths(self.paths, start if start else self.root))
  
      def paths_by_repo(self) -> Dict[Path, List[Path]]:
          repos = collections.defaultdict(list)
  
          for path in self.paths:
              repos[git_repo.root(path)].append(path)
  
          return repos
  
  
  class _Filter(NamedTuple):
      endswith: Tuple[str, ...] = ('', )
      exclude: Tuple[Pattern[str], ...] = ()
  
      def matches(self, path: str) -> bool:
          return (any(path.endswith(end) for end in self.endswith)
                  and not any(exp.search(path) for exp in self.exclude))
  
  
  def _print_ui(*args) -> None:
      """Prints to stdout and flushes to stay in sync with logs on stderr."""
      print(*args, flush=True)
  
  
  class Presubmit:
      """Runs a series of presubmit checks on a list of files."""
      def __init__(self, root: Path, repos: Sequence[Path],
                   output_directory: Path, paths: Sequence[Path],
                   package_root: Path):
          self._root = root.resolve()
          self._repos = tuple(repos)
          self._output_directory = output_directory.resolve()
          self._paths = tuple(paths)
          self._relative_paths = tuple(
              tools.relative_paths(self._paths, self._root))
          self._package_root = package_root.resolve()
  
      def run(self, program: Program, keep_going: bool = False) -> bool:
          """Executes a series of presubmit checks on the paths."""
  
          checks = self._apply_filters(program)
  
          _LOG.debug('Running %s for %s', program.title(), self._root.name)
          _print_ui(_title(f'{self._root.name}: {program.title()}'))
  
          _LOG.info('%d of %d checks apply to %s in %s', len(checks),
                    len(program), plural(self._paths, 'file'), self._root)
  
          _print_ui()
          for line in tools.file_summary(self._relative_paths):
              _print_ui(line)
          _print_ui()
  
          if not self._paths:
              _print_ui(color_yellow('No files are being checked!'))
  
          _LOG.debug('Checks:\n%s', '\n'.join(c.name for c, _ in checks))
  
          start_time: float = time.time()
          passed, failed, skipped = self._execute_checks(checks, keep_going)
          self._log_summary(time.time() - start_time, passed, failed, skipped)
  
          return not failed and not skipped
  
      def _apply_filters(
              self, program: Sequence[Callable]
      ) -> List[Tuple['_Check', Sequence[Path]]]:
          """Returns list of (check, paths) for checks that should run."""
          checks = [c if isinstance(c, _Check) else _Check(c) for c in program]
          filter_to_checks: Dict[_Filter,
                                 List[_Check]] = collections.defaultdict(list)
  
          for check in checks:
              filter_to_checks[check.filter].append(check)
  
          check_to_paths = self._map_checks_to_paths(filter_to_checks)
          return [(c, check_to_paths[c]) for c in checks if c in check_to_paths]
  
      def _map_checks_to_paths(
          self, filter_to_checks: Dict[_Filter, List['_Check']]
      ) -> Dict['_Check', Sequence[Path]]:
          checks_to_paths: Dict[_Check, Sequence[Path]] = {}
  
          posix_paths = tuple(p.as_posix() for p in self._relative_paths)
  
          for filt, checks in filter_to_checks.items():
              filtered_paths = tuple(
                  path for path, filter_path in zip(self._paths, posix_paths)
                  if filt.matches(filter_path))
  
              for check in checks:
                  if filtered_paths or check.always_run:
                      checks_to_paths[check] = filtered_paths
                  else:
                      _LOG.debug('Skipping "%s": no relevant files', check.name)
  
          return checks_to_paths
  
      def _log_summary(self, time_s: float, passed: int, failed: int,
                       skipped: int) -> None:
          summary_items = []
          if passed:
              summary_items.append(f'{passed} passed')
          if failed:
              summary_items.append(f'{failed} failed')
          if skipped:
              summary_items.append(f'{skipped} not run')
          summary = ', '.join(summary_items) or 'nothing was done'
  
          result = _Result.FAIL if failed or skipped else _Result.PASS
          total = passed + failed + skipped
  
          _LOG.debug('Finished running %d checks on %s in %.1f s', total,
                     plural(self._paths, 'file'), time_s)
          _LOG.debug('Presubmit checks %s: %s', result.value, summary)
  
          _print_ui(
              _box(
                  _SUMMARY_BOX, result.colorized(_LEFT, invert=True),
                  f'{total} checks on {plural(self._paths, "file")}: {summary}',
                  _format_time(time_s)))
  
      @contextlib.contextmanager
      def _context(self, name: str, paths: Tuple[Path, ...]):
          # There are many characters banned from filenames on Windows. To
          # simplify things, just strip everything that's not a letter, digit,
          # or underscore.
          sanitized_name = re.sub(r'[\W_]+', '_', name).lower()
          output_directory = self._output_directory.joinpath(sanitized_name)
          os.makedirs(output_directory, exist_ok=True)
  
          handler = logging.FileHandler(output_directory.joinpath('step.log'),
                                        mode='w')
          handler.setLevel(logging.DEBUG)
  
          try:
              _LOG.addHandler(handler)
  
              yield PresubmitContext(
                  root=self._root,
                  repos=self._repos,
                  output_dir=output_directory,
                  paths=paths,
                  package_root=self._package_root,
              )
  
          finally:
              _LOG.removeHandler(handler)
  
      def _execute_checks(self, program,
                          keep_going: bool) -> Tuple[int, int, int]:
          """Runs presubmit checks; returns (passed, failed, skipped) lists."""
          passed = failed = 0
  
          for i, (check, paths) in enumerate(program, 1):
              with self._context(check.name, paths) as ctx:
                  result = check.run(ctx, i, len(program))
  
              if result is _Result.PASS:
                  passed += 1
              elif result is _Result.CANCEL:
                  break
              else:
                  failed += 1
                  if not keep_going:
                      break
  
          return passed, failed, len(program) - passed - failed
  
  
  def _process_pathspecs(repos: Iterable[Path],
                         pathspecs: Iterable[str]) -> Dict[Path, List[str]]:
      pathspecs_by_repo: Dict[Path, List[str]] = {repo: [] for repo in repos}
      repos_with_paths: Set[Path] = set()
  
      for pathspec in pathspecs:
          # If the pathspec is a path to an existing file, only use it for the
          # repo it is in.
          if os.path.exists(pathspec):
              # Raise an exception if the path exists but is not in a known repo.
              repo = git_repo.within_repo(pathspec)
              if repo not in pathspecs_by_repo:
                  raise ValueError(
                      f'{pathspec} is not in a Git repository in this presubmit')
  
              # Make the path relative to the repo's root.
              pathspecs_by_repo[repo].append(os.path.relpath(pathspec, repo))
              repos_with_paths.add(repo)
          else:
              # Pathspecs that are not paths (e.g. '*.h') are used for all repos.
              for patterns in pathspecs_by_repo.values():
                  patterns.append(pathspec)
  
      # If any paths were specified, only search for paths in those repos.
      if repos_with_paths:
          for repo in set(pathspecs_by_repo) - repos_with_paths:
              del pathspecs_by_repo[repo]
  
      return pathspecs_by_repo
  
  
  def run(program: Sequence[Callable],
          root: Path,
          repos: Collection[Path] = (),
          base: Optional[str] = None,
          paths: Sequence[str] = (),
          exclude: Sequence[Pattern] = (),
          output_directory: Optional[Path] = None,
          package_root: Path = None,
          keep_going: bool = False) -> bool:
      """Lists files in the current Git repo and runs a Presubmit with them.
  
      This changes the directory to the root of the Git repository after listing
      paths, so all presubmit checks can assume they run from there.
  
      The paths argument contains Git pathspecs. If no pathspecs are provided, all
      paths in all repos are included. If paths to files or directories are
      provided, only files within those repositories are searched. Patterns are
      searched across all repositories. For example, if the pathspecs "my_module/"
      and "*.h", paths under "my_module/" in the containing repo and paths in all
      repos matching "*.h" will be included in the presubmit.
  
      Args:
          program: list of presubmit check functions to run
          root: root path of the project
          repos: paths to the roots of Git repositories to check
          name: name to use to refer to this presubmit check run
          base: optional base Git commit to list files against
          paths: optional list of Git pathspecs to run the checks against
          exclude: regular expressions for Posix-style paths to exclude
          output_directory: where to place output files
          package_root: where to place package files
          keep_going: whether to continue running checks if an error occurs
  
      Returns:
          True if all presubmit checks succeeded
      """
      repos = [repo.resolve() for repo in repos]
  
      for repo in repos:
          if git_repo.root(repo) != repo:
              raise ValueError(f'{repo} is not the root of a Git repo; '
                               'presubmit checks must be run from a Git repo')
  
      pathspecs_by_repo = _process_pathspecs(repos, paths)
  
      files: List[Path] = []
  
      for repo, pathspecs in pathspecs_by_repo.items():
          files += tools.exclude_paths(
              exclude, git_repo.list_files(base, pathspecs, repo), root)
  
          _LOG.info(
              'Checking %s',
              git_repo.describe_files(repo, repo, base, pathspecs, exclude))
  
      if output_directory is None:
          output_directory = root / '.presubmit'
  
      if package_root is None:
          package_root = output_directory / 'packages'
  
      presubmit = Presubmit(
          root=root,
          repos=repos,
          output_directory=output_directory,
          paths=files,
          package_root=package_root,
      )
  
      if not isinstance(program, Program):
          program = Program('', program)
  
      return presubmit.run(program, keep_going)
  
  
  class _Check:
      """Wraps a presubmit check function.
  
      This class consolidates the logic for running and logging a presubmit check.
      It also supports filtering the paths passed to the presubmit check.
      """
      def __init__(self,
                   check_function: Callable,
                   path_filter: _Filter = _Filter(),
                   always_run: bool = True):
          _ensure_is_valid_presubmit_check_function(check_function)
  
          self._check: Callable = check_function
          self.filter: _Filter = path_filter
          self.always_run: bool = always_run
  
          # Since _Check wraps a presubmit function, adopt that function's name.
          self.__name__ = self._check.__name__
  
      @property
      def name(self):
          return self.__name__
  
      def run(self, ctx: PresubmitContext, count: int, total: int) -> _Result:
          """Runs the presubmit check on the provided paths."""
  
          _print_ui(
              _box(_CHECK_UPPER, f'{count}/{total}', self.name,
                   plural(ctx.paths, "file")))
  
          _LOG.debug('[%d/%d] Running %s on %s', count, total, self.name,
                     plural(ctx.paths, "file"))
  
          start_time_s = time.time()
          result = self._call_function(ctx)
          time_str = _format_time(time.time() - start_time_s)
          _LOG.debug('%s %s', self.name, result.value)
  
          _print_ui(
              _box(_CHECK_LOWER, result.colorized(_LEFT), self.name, time_str))
          _LOG.debug('%s duration:%s', self.name, time_str)
  
          return result
  
      def _call_function(self, ctx: PresubmitContext) -> _Result:
          try:
              self._check(ctx)
          except PresubmitFailure as failure:
              if str(failure):
                  _LOG.warning('%s', failure)
              return _Result.FAIL
          except Exception as failure:  # pylint: disable=broad-except
              _LOG.exception('Presubmit check %s failed!', self.name)
              return _Result.FAIL
          except KeyboardInterrupt:
              _print_ui()
              return _Result.CANCEL
  
          return _Result.PASS
  
      def __call__(self, ctx: PresubmitContext, *args, **kwargs):
          """Calling a _Check calls its underlying function directly.
  
        This makes it possible to call functions wrapped by @filter_paths. The
        prior filters are ignored, so new filters may be applied.
        """
          return self._check(ctx, *args, **kwargs)
  
  
  def _required_args(function: Callable) -> Iterable[Parameter]:
      """Returns the required arguments for a function."""
      optional_types = Parameter.VAR_POSITIONAL, Parameter.VAR_KEYWORD
  
      for param in signature(function).parameters.values():
          if param.default is param.empty and param.kind not in optional_types:
              yield param
  
  
  def _ensure_is_valid_presubmit_check_function(check: Callable) -> None:
      """Checks if a Callable can be used as a presubmit check."""
      try:
          required_args = tuple(_required_args(check))
      except (TypeError, ValueError):
          raise TypeError('Presubmit checks must be callable, but '
                          f'{check!r} is a {type(check).__name__}')
  
      if len(required_args) != 1:
          raise TypeError(
              f'Presubmit check functions must have exactly one required '
              f'positional argument (the PresubmitContext), but '
              f'{check.__name__} has {len(required_args)} required arguments' +
              (f' ({", ".join(a.name for a in required_args)})'
               if required_args else ''))
  
  
  def _make_str_tuple(value: Iterable[str]) -> Tuple[str, ...]:
      return tuple([value] if isinstance(value, str) else value)
  
  
  def filter_paths(endswith: Iterable[str] = (''),
                   exclude: Iterable[Union[Pattern[str], str]] = (),
                   always_run: bool = False) -> Callable[[Callable], _Check]:
      """Decorator for filtering the paths list for a presubmit check function.
  
      Path filters only apply when the function is used as a presubmit check.
      Filters are ignored when the functions are called directly. This makes it
      possible to reuse functions wrapped in @filter_paths in other presubmit
      checks, potentially with different path filtering rules.
  
      Args:
          endswith: str or iterable of path endings to include
          exclude: regular expressions of paths to exclude
  
      Returns:
          a wrapped version of the presubmit function
      """
      def filter_paths_for_function(function: Callable):
          return _Check(function,
                        _Filter(_make_str_tuple(endswith),
                                tuple(re.compile(e) for e in exclude)),
                        always_run=always_run)
  
      return filter_paths_for_function
  
  
  @filter_paths(endswith='.h', exclude=(r'\.pb\.h$', ))
  def pragma_once(ctx: PresubmitContext) -> None:
      """Presubmit check that ensures all header files contain '#pragma once'."""
  
      for path in ctx.paths:
          with open(path) as file:
              for line in file:
                  if line.startswith('#pragma once'):
                      break
              else:
                  raise PresubmitFailure('#pragma once is missing!', path=path)
  
  
  def call(*args, **kwargs) -> None:
      """Optional subprocess wrapper that causes a PresubmitFailure on errors."""
      attributes, command = tools.format_command(args, kwargs)
      _LOG.debug('[RUN] %s\n%s', attributes, command)
  
      process = subprocess.run(args,
                               stdout=subprocess.PIPE,
                               stderr=subprocess.STDOUT,
                               **kwargs)
      logfunc = _LOG.warning if process.returncode else _LOG.debug
  
      logfunc('[FINISHED]\n%s', command)
      logfunc('[RESULT] %s with return code %d',
              'Failed' if process.returncode else 'Passed', process.returncode)
  
      output = process.stdout.decode(errors='backslashreplace')
      if output:
          logfunc('[OUTPUT]\n%s', output)
  
      if process.returncode:
          raise PresubmitFailure
  