code_clean.py

#!/usr/bin/env python3
# SPDX-License-Identifier: GPL-2.0-or-later

"""
Example:
  ./source/tools/utils/code_clean.py /src/cmake_debug --match ".*/editmesh_.*" --fix=use_const_vars

Note: currently this is limited to paths in "source/" and "intern/",
we could change this if it's needed.
"""

import argparse
import re
import subprocess
import sys
import os
import string

from typing import (
    Any,
    Dict,
    Generator,
    List,
    Optional,
    Sequence,
    Tuple,
    Type,
)

# List of (source_file, all_arguments)
ProcessedCommands = List[Tuple[str, str]]

USE_MULTIPROCESS = True

VERBOSE = False

# Print the output of the compiler (_very_ noisy, only useful for troubleshooting compiler issues).
VERBOSE_COMPILER = False

# Print the result of each attempted edit:
#
# - Causes code not to compile.
# - Compiles but changes the resulting behavior.
# - Succeeds.
VERBOSE_EDIT_ACTION = False


BASE_DIR = os.path.abspath(os.path.dirname(__file__))

SOURCE_DIR = os.path.normpath(os.path.join(BASE_DIR, "..", "..", ".."))


# -----------------------------------------------------------------------------
# Generic Constants

# Sorted numeric types.
# Intentionally missing are "unsigned".
BUILT_IN_NUMERIC_TYPES = (
    "bool",
    "char",
    "char32_t",
    "double",
    "float",
    "int",
    "int16_t",
    "int32_t",
    "int64_t",
    "int8_t",
    "intptr_t",
    "long",
    "off_t",
    "ptrdiff_t",
    "short",
    "size_t",
    "ssize_t",
    "uchar",
    "uint",
    "uint16_t",
    "uint32_t",
    "uint64_t",
    "uint8_t",
    "uintptr_t",
    "ulong",
    "ushort",
)

IDENTIFIER_CHARS = set(string.ascii_letters + "_" + string.digits)


# -----------------------------------------------------------------------------
# General Utilities

# Note that we could use a hash, however there is no advantage, compare it's contents.
def file_as_bytes(filename: str) -> bytes:
    with open(filename, 'rb') as fh:
        return fh.read()


def line_from_span(text: str, start: int, end: int) -> str:
    while start > 0 and text[start - 1] != '\n':
        start -= 1
    while end < len(text) and text[end] != '\n':
        end += 1
    return text[start:end]


def files_recursive_with_ext(path: str, ext: Tuple[str, ...]) -> Generator[str, None, None]:
    for dirpath, dirnames, filenames in os.walk(path):
        # skip '.git' and other dot-files.
        dirnames[:] = [d for d in dirnames if not d.startswith(".")]
        for filename in filenames:
            if filename.endswith(ext):
                yield os.path.join(dirpath, filename)


def text_matching_bracket_forward(
        data: str,
        pos_beg: int,
        pos_limit: int,
        beg_bracket: str,
        end_bracket: str,
) -> int:
    """
    Return the matching bracket or -1.

    .. note:: This is not sophisticated, brackets in strings will confuse the function.
    """
    level = 1

    # The next bracket.
    pos = pos_beg + 1

    # Clamp the limit.
    limit = min(pos_beg + pos_limit, len(data))

    while pos < limit:
        c = data[pos]
        if c == beg_bracket:
            level += 1
        elif c == end_bracket:
            level -= 1
            if level == 0:
                return pos
        pos += 1
    return -1


def text_matching_bracket_backward(
        data: str,
        pos_end: int,
        pos_limit: int,
        beg_bracket: str,
        end_bracket: str,
) -> int:
    """
    Return the matching bracket or -1.

    .. note:: This is not sophisticated, brackets in strings will confuse the function.
    """
    level = 1

    # The next bracket.
    pos = pos_end - 1

    # Clamp the limit.
    limit = max(0, pos_limit)

    while pos >= limit:
        c = data[pos]
        if c == end_bracket:
            level += 1
        elif c == beg_bracket:
            level -= 1
            if level == 0:
                return pos
        pos -= 1
    return -1


# -----------------------------------------------------------------------------
# Execution Wrappers

def run(args: str, *, quiet: bool) -> int:
    if VERBOSE_COMPILER and not quiet:
        out = sys.stdout.fileno()
    else:
        out = subprocess.DEVNULL

    import shlex
    p = subprocess.Popen(shlex.split(args), stdout=out, stderr=out)
    p.wait()
    return p.returncode


# -----------------------------------------------------------------------------
# Build System Access

def cmake_cache_var(cmake_dir: str, var: str) -> Optional[str]:
    with open(os.path.join(cmake_dir, "CMakeCache.txt"), encoding='utf-8') as cache_file:
        lines = [
            l_strip for l in cache_file
            if (l_strip := l.strip())
            if not l_strip.startswith(("//", "#"))
        ]

    for l in lines:
        if l.split(":")[0] == var:
            return l.split("=", 1)[-1]
    return None


RE_CFILE_SEARCH = re.compile(r"\s\-c\s([\S]+)")


def process_commands(cmake_dir: str, data: Sequence[str]) -> Optional[ProcessedCommands]:
    compiler_c = cmake_cache_var(cmake_dir, "CMAKE_C_COMPILER")
    compiler_cxx = cmake_cache_var(cmake_dir, "CMAKE_CXX_COMPILER")
    if compiler_c is None:
        sys.stderr.write("Can't find C compiler in %r" % cmake_dir)
        return None
    if compiler_cxx is None:
        sys.stderr.write("Can't find C++ compiler in %r" % cmake_dir)
        return None

    file_args = []

    for l in data:
        if (
                (compiler_c in l) or
                (compiler_cxx in l)
        ):
            # Extract:
            #   -c SOME_FILE
            c_file_search = re.search(RE_CFILE_SEARCH, l)
            if c_file_search is not None:
                c_file = c_file_search.group(1)
                file_args.append((c_file, l))
            else:
                # could print, NO C FILE FOUND?
                pass

    file_args.sort()

    return file_args


def find_build_args_ninja(build_dir: str) -> Optional[ProcessedCommands]:
    import time
    cmake_dir = build_dir
    make_exe = "ninja"
    process = subprocess.Popen(
        [make_exe, "-t", "commands"],
        stdout=subprocess.PIPE,
        cwd=build_dir,
    )
    while process.poll():
        time.sleep(1)
    assert process.stdout is not None

    out = process.stdout.read()
    process.stdout.close()
    # print("done!", len(out), "bytes")
    data = out.decode("utf-8", errors="ignore").split("\n")
    return process_commands(cmake_dir, data)


def find_build_args_make(build_dir: str) -> Optional[ProcessedCommands]:
    import time
    make_exe = "make"
    process = subprocess.Popen(
        [make_exe, "--always-make", "--dry-run", "--keep-going", "VERBOSE=1"],
        stdout=subprocess.PIPE,
        cwd=build_dir,
    )
    while process.poll():
        time.sleep(1)
    assert process.stdout is not None

    out = process.stdout.read()
    process.stdout.close()

    # print("done!", len(out), "bytes")
    data = out.decode("utf-8", errors="ignore").split("\n")
    return process_commands(build_dir, data)


# -----------------------------------------------------------------------------
# Create Edit Lists

# Create an edit list from a file, in the format:
#
#    [((start_index, end_index), text_to_replace), ...]
#
# Note that edits should not overlap, in the _very_ rare case overlapping edits are needed,
# this could be run multiple times on the same code-base.
#
# Although this seems like it's not a common use-case.

from collections import namedtuple
Edit = namedtuple(
    "Edit", (
        # Keep first, for sorting.
        "span",

        "content",
        "content_fail",

        # Optional.
        "extra_build_args",
    ),

    defaults=(
        # `extra_build_args`.
        None,
    )
)
del namedtuple


class EditGenerator:
    __slots__ = ()

    def __new__(cls, *args: Tuple[Any], **kwargs: Dict[str, Any]) -> Any:
        raise RuntimeError("%s should not be instantiated" % cls)

    @staticmethod
    def edit_list_from_file(_source: str, _data: str, _shared_edit_data: Any) -> List[Edit]:
        raise RuntimeError("This function must be overridden by it's subclass!")
        return []

    @staticmethod
    def setup() -> Any:
        return None

    @staticmethod
    def teardown(_shared_edit_data: Any) -> None:
        pass


class edit_generators:
    # fake module.

    class sizeof_fixed_array(EditGenerator):
        """
        Use fixed size array syntax with `sizeof`:

        Replace:
          sizeof(float) * 4 * 4
        With:
          sizeof(float[4][4])
        """
        @staticmethod
        def edit_list_from_file(_source: str, data: str, _shared_edit_data: Any) -> List[Edit]:
            edits = []

            for match in re.finditer(r"sizeof\(([a-zA-Z_]+)\) \* (\d+) \* (\d+)", data):
                edits.append(Edit(
                    span=match.span(),
                    content='sizeof(%s[%s][%s])' % (match.group(1), match.group(2), match.group(3)),
                    content_fail='__ALWAYS_FAIL__',
                ))

            for match in re.finditer(r"sizeof\(([a-zA-Z_]+)\) \* (\d+)", data):
                edits.append(Edit(
                    span=match.span(),
                    content='sizeof(%s[%s])' % (match.group(1), match.group(2)),
                    content_fail='__ALWAYS_FAIL__',
                ))

            for match in re.finditer(r"\b(\d+) \* sizeof\(([a-zA-Z_]+)\)", data):
                edits.append(Edit(
                    span=match.span(),
                    content='sizeof(%s[%s])' % (match.group(2), match.group(1)),
                    content_fail='__ALWAYS_FAIL__',
                ))
            return edits

    class use_const(EditGenerator):
        """
        Use const variables:

        Replace:
          float abc[3] = {0, 1, 2};
        With:
          const float abc[3] = {0, 1, 2};

        Replace:
          float abc[3]
        With:
          const float abc[3]

        As well as casts.

        Replace:
          (float *)
        With:
          (const float *)

        Replace:
          (float (*))
        With:
          (const float (*))
        """
        @staticmethod
        def edit_list_from_file(_source: str, data: str, _shared_edit_data: Any) -> List[Edit]:
            edits = []

            # `float abc[3] = {0, 1, 2};` -> `const float abc[3] = {0, 1, 2};`
            for match in re.finditer(r"(\(|, |  )([a-zA-Z_0-9]+ [a-zA-Z_0-9]+\[)\b([^\n]+ = )", data):
                edits.append(Edit(
                    span=match.span(),
                    content='%s const %s%s' % (match.group(1), match.group(2), match.group(3)),
                    content_fail='__ALWAYS_FAIL__',
                ))

            # `float abc[3]` -> `const float abc[3]`
            for match in re.finditer(r"(\(|, )([a-zA-Z_0-9]+ [a-zA-Z_0-9]+\[)", data):
                edits.append(Edit(
                    span=match.span(),
                    content='%s const %s' % (match.group(1), match.group(2)),
                    content_fail='__ALWAYS_FAIL__',
                ))

            # `(float *)`      -> `(const float *)`
            # `(float (*))`    -> `(const float (*))`
            # `(float (*)[4])` -> `(const float (*)[4])`
            for match in re.finditer(
                    r"(\()"
                    r"([a-zA-Z_0-9]+\s*)"
                    r"(\*+\)|\(\*+\))"
                    r"(|\[[a-zA-Z_0-9]+\])",
                    data,
            ):
                edits.append(Edit(
                    span=match.span(),
                    content='%sconst %s%s%s' % (match.group(1), match.group(2), match.group(3), match.group(4)),
                    content_fail='__ALWAYS_FAIL__',
                ))

            return edits

    class use_zero_before_float_suffix(EditGenerator):
        """
        Use zero before the float suffix.

        Replace:
          1.f
        With:
          1.0f

        Replace:
          1.0F
        With:
          1.0f
        """
        @staticmethod
        def edit_list_from_file(_source: str, data: str, _shared_edit_data: Any) -> List[Edit]:
            edits = []

            # `1.f` -> `1.0f`
            for match in re.finditer(r"\b(\d+)\.([fF])\b", data):
                edits.append(Edit(
                    span=match.span(),
                    content='%s.0%s' % (match.group(1), match.group(2)),
                    content_fail='__ALWAYS_FAIL__',
                ))

            # `1.0F` -> `1.0f`
            for match in re.finditer(r"\b(\d+\.\d+)F\b", data):
                edits.append(Edit(
                    span=match.span(),
                    content='%sf' % (match.group(1),),
                    content_fail='__ALWAYS_FAIL__',
                ))

            return edits

    class use_brief_types(EditGenerator):
        """
        Use zero before the float suffix.

        Replace:
          unsigned int
        With:
          uint
        """
        @staticmethod
        def edit_list_from_file(_source: str, data: str, _shared_edit_data: Any) -> List[Edit]:
            edits = []

            # `unsigned char` -> `uchar`.
            for match in re.finditer(r"(unsigned)\s+([a-z]+)", data):
                edits.append(Edit(
                    span=match.span(),
                    content='u%s' % match.group(2),
                    content_fail='__ALWAYS_FAIL__',
                ))

            # There may be some remaining uses of `unsigned` without any integer type afterwards.
            # `unsigned` -> `uint`.
            for match in re.finditer(r"\bunsigned\b", data):
                edits.append(Edit(
                    span=match.span(),
                    content='uint',
                    content_fail='__ALWAYS_FAIL__',
                ))

            return edits

    class use_elem_macro(EditGenerator):
        """
        Use the `ELEM` macro for more abbreviated expressions.

        Replace:
          (a == b || a == c)
          (a != b && a != c)
        With:
          (ELEM(a, b, c))
          (!ELEM(a, b, c))
        """
        @staticmethod
        def edit_list_from_file(_source: str, data: str, _shared_edit_data: Any) -> List[Edit]:
            edits = []

            for use_brackets in (True, False):

                test_equal = (
                    r'([^\|\(\)]+)'  # group 1 (no (|))
                    r'\s+==\s+'
                    r'([^\|\(\)]+)'  # group 2 (no (|))
                )

                test_not_equal = (
                    r'([^\|\(\)]+)'  # group 1 (no (|))
                    r'\s+!=\s+'
                    r'([^\|\(\)]+)'  # group 2 (no (|))
                )

                if use_brackets:
                    test_equal = r'\(' + test_equal + r'\)'
                    test_not_equal = r'\(' + test_not_equal + r'\)'

                for is_equal in (True, False):
                    for n in reversed(range(2, 64)):
                        if is_equal:
                            re_str = r'\(' + r'\s+\|\|\s+'.join([test_equal] * n) + r'\)'
                        else:
                            re_str = r'\(' + r'\s+\&\&\s+'.join([test_not_equal] * n) + r'\)'

                        for match in re.finditer(re_str, data):
                            var = match.group(1)
                            var_rest = []
                            groups = match.groups()
                            groups_paired = [(groups[i * 2], groups[i * 2 + 1]) for i in range(len(groups) // 2)]
                            found = True
                            for a, b in groups_paired:
                                # Unlikely but possible the checks are swapped.
                                if b == var and a != var:
                                    a, b = b, a

                                if a != var:
                                    found = False
                                    break
                                var_rest.append(b)

                            if found:
                                edits.append(Edit(
                                    span=match.span(),
                                    content='(%sELEM(%s, %s))' % (
                                        ('' if is_equal else '!'),
                                        var,
                                        ', '.join(var_rest),
                                    ),
                                    # Use same expression otherwise this can change values
                                    # inside assert when it shouldn't.
                                    content_fail='(%s__ALWAYS_FAIL__(%s, %s))' % (
                                        ('' if is_equal else '!'),
                                        var,
                                        ', '.join(var_rest),
                                    ),
                                ))

            return edits

    class use_str_elem_macro(EditGenerator):
        """
        Use `STR_ELEM` macro:

        Replace:
          (STREQ(a, b) || STREQ(a, c))
        With:
          (STR_ELEM(a, b, c))
        """
        @staticmethod
        def edit_list_from_file(_source: str, data: str, _shared_edit_data: Any) -> List[Edit]:
            edits = []

            for use_brackets in (True, False):

                test_equal = (
                    r'STREQ'
                    r'\('
                    r'([^\|\(\),]+)'  # group 1 (no (|,))
                    r',\s+'
                    r'([^\|\(\),]+)'  # group 2 (no (|,))
                    r'\)'
                )

                test_not_equal = (
                    '!'  # Only difference.
                    r'STREQ'
                    r'\('
                    r'([^\|\(\),]+)'  # group 1 (no (|,))
                    r',\s+'
                    r'([^\|\(\),]+)'  # group 2 (no (|,))
                    r'\)'
                )

                if use_brackets:
                    test_equal = r'\(' + test_equal + r'\)'
                    test_not_equal = r'\(' + test_not_equal + r'\)'

                for is_equal in (True, False):
                    for n in reversed(range(2, 64)):
                        if is_equal:
                            re_str = r'\(' + r'\s+\|\|\s+'.join([test_equal] * n) + r'\)'
                        else:
                            re_str = r'\(' + r'\s+\&\&\s+'.join([test_not_equal] * n) + r'\)'

                        for match in re.finditer(re_str, data):
                            var = match.group(1)
                            var_rest = []
                            groups = match.groups()
                            groups_paired = [(groups[i * 2], groups[i * 2 + 1]) for i in range(len(groups) // 2)]
                            found = True
                            for a, b in groups_paired:
                                # Unlikely but possible the checks are swapped.
                                if b == var and a != var:
                                    a, b = b, a

                                if a != var:
                                    found = False
                                    break
                                var_rest.append(b)

                            if found:
                                edits.append(Edit(
                                    span=match.span(),
                                    content='(%sSTR_ELEM(%s, %s))' % (
                                        ('' if is_equal else '!'),
                                        var,
                                        ', '.join(var_rest),
                                    ),
                                    # Use same expression otherwise this can change values
                                    # inside assert when it shouldn't.
                                    content_fail='(%s__ALWAYS_FAIL__(%s, %s))' % (
                                        ('' if is_equal else '!'),
                                        var,
                                        ', '.join(var_rest),
                                    ),
                                ))

            return edits

    class use_const_vars(EditGenerator):
        """
        Use `const` where possible:

        Replace:
          float abc[3] = {0, 1, 2};
        With:
          const float abc[3] = {0, 1, 2};
        """
        @staticmethod
        def edit_list_from_file(_source: str, data: str, _shared_edit_data: Any) -> List[Edit]:
            edits = []

            # for match in re.finditer(r"(  [a-zA-Z0-9_]+ [a-zA-Z0-9_]+ = [A-Z][A-Z_0-9_]*;)", data):
            #     edits.append(Edit(
            #         span=match.span(),
            #         content='const %s' % (match.group(1).lstrip()),
            #         content_fail='__ALWAYS_FAIL__',
            #     ))

            for match in re.finditer(r"(  [a-zA-Z0-9_]+ [a-zA-Z0-9_]+ = .*;)", data):
                edits.append(Edit(
                    span=match.span(),
                    content='const %s' % (match.group(1).lstrip()),
                    content_fail='__ALWAYS_FAIL__',
                ))

            return edits

    class remove_return_parens(EditGenerator):
        """
        Remove redundant parenthesis around return arguments:

        Replace:
          return (value);
        With:
          return value;
        """
        @staticmethod
        def edit_list_from_file(_source: str, data: str, _shared_edit_data: Any) -> List[Edit]:
            edits = []

            # Remove `return (NULL);`
            for match in re.finditer(r"return \(([a-zA-Z_0-9]+)\);", data):
                edits.append(Edit(
                    span=match.span(),
                    content='return %s;' % (match.group(1)),
                    content_fail='return __ALWAYS_FAIL__;',
                ))
            return edits

    class use_streq_macro(EditGenerator):
        """
        Use `STREQ` macro:

        Replace:
          strcmp(a, b) == 0
        With:
          STREQ(a, b)

        Replace:
          strcmp(a, b) != 0
        With:
          !STREQ(a, b)
        """
        @staticmethod
        def edit_list_from_file(_source: str, data: str, _shared_edit_data: Any) -> List[Edit]:
            edits = []

            # `strcmp(a, b) == 0` -> `STREQ(a, b)`
            for match in re.finditer(r"\bstrcmp\((.*)\) == 0", data):
                edits.append(Edit(
                    span=match.span(),
                    content='STREQ(%s)' % (match.group(1)),
                    content_fail='__ALWAYS_FAIL__',
                ))
            for match in re.finditer(r"!strcmp\((.*)\)", data):
                edits.append(Edit(
                    span=match.span(),
                    content='STREQ(%s)' % (match.group(1)),
                    content_fail='__ALWAYS_FAIL__',
                ))

            # `strcmp(a, b) != 0` -> `!STREQ(a, b)`
            for match in re.finditer(r"\bstrcmp\((.*)\) != 0", data):
                edits.append(Edit(
                    span=match.span(),
                    content='!STREQ(%s)' % (match.group(1)),
                    content_fail='__ALWAYS_FAIL__',
                ))
            for match in re.finditer(r"\bstrcmp\((.*)\)", data):
                edits.append(Edit(
                    span=match.span(),
                    content='!STREQ(%s)' % (match.group(1)),
                    content_fail='__ALWAYS_FAIL__',
                ))

            return edits

    class use_array_size_macro(EditGenerator):
        """
        Use macro for an error checked array size:

        Replace:
          sizeof(foo) / sizeof(*foo)
        With:
          ARRAY_SIZE(foo)
        """
        @staticmethod
        def edit_list_from_file(_source: str, data: str, _shared_edit_data: Any) -> List[Edit]:
            edits = []
            # Note that this replacement is only valid in some cases,
            # so only apply with validation that binary output matches.
            for match in re.finditer(r"\bsizeof\((.*)\) / sizeof\([^\)]+\)", data):
                edits.append(Edit(
                    span=match.span(),
                    content='ARRAY_SIZE(%s)' % match.group(1),
                    content_fail='__ALWAYS_FAIL__',
                ))

            return edits

    class parenthesis_cleanup(EditGenerator):
        """
        Use macro for an error checked array size:

        Replace:
          ((a + b))
        With:
          (a + b)

        Replace:
          (func(a + b))
        With:
          func(a + b)

        Note that the `CFLAGS` should be set so missing parentheses that contain assignments - error instead of warn:
        With GCC: `-Werror=parentheses`
        """
        @staticmethod
        def edit_list_from_file(_source: str, data: str, _shared_edit_data: Any) -> List[Edit]:
            edits = []

            # Give up after searching for a bracket this many characters and finding none.
            bracket_seek_limit = 4000

            # Don't match double brackets because this will not match multiple overlapping matches
            # Where 3 brackets should be checked as two separate pairs.
            for match in re.finditer(r"(\()", data):
                outer_beg = match.span()[0]
                inner_beg = outer_beg + 1
                if data[inner_beg] != "(":
                    continue

                inner_end = text_matching_bracket_forward(data, inner_beg, inner_beg + bracket_seek_limit, "(", ")")
                if inner_end == -1:
                    continue
                outer_beg = inner_beg - 1
                outer_end = text_matching_bracket_forward(data, outer_beg, inner_end + 1, "(", ")")
                if outer_end != inner_end + 1:
                    continue

                text = data[inner_beg:inner_end + 1]
                edits.append(Edit(
                    span=(outer_beg, outer_end + 1),
                    content=text,
                    content_fail='(__ALWAYS_FAIL__)',
                ))

            # Handle `(func(a + b))` -> `func(a + b)`
            for match in re.finditer(r"(\))", data):
                inner_end = match.span()[0]
                outer_end = inner_end + 1
                if data[outer_end] != ")":
                    continue

                inner_beg = text_matching_bracket_backward(data, inner_end, inner_end - bracket_seek_limit, "(", ")")
                if inner_beg == -1:
                    continue
                outer_beg = text_matching_bracket_backward(data, outer_end, outer_end - bracket_seek_limit, "(", ")")
                if outer_beg == -1:
                    continue

                # The text between the first two opening brackets:
                # `(function_name(a + b))` -> `function_name`.
                text = data[outer_beg + 1:inner_beg]

                # Handled in the first loop looking for forward brackets.
                if text == "":
                    continue

                # Don't convert `prefix(func(a + b))` -> `prefixfunc(a + b)`
                if data[outer_beg - 1] in IDENTIFIER_CHARS:
                    continue

                # Don't convert `static_cast<float>(foo(bar))` -> `static_cast<float>foo(bar)`
                # While this will always fail to compile it slows down tests.
                if data[outer_beg - 1] == ">":
                    continue

                # Exact rule here is arbitrary, in general though spaces mean there are operations
                # that can use the brackets.
                if " " in text:
                    continue

                # Search back an arbitrary number of chars 8 should be enough
                # but manual formatting can add additional white-space, so increase
                # the size to account for that.
                prefix = data[max(outer_beg - 20, 0):outer_beg].strip()
                if prefix:
                    # Avoid `if (SOME_MACRO(..)) {..}` -> `if SOME_MACRO(..) {..}`
                    # While correct it relies on parenthesis within the macro which isn't ideal.
                    if prefix.split()[-1] in {"if", "while", "switch"}:
                        continue
                    # Avoid `*(--foo)` -> `*--foo`.
                    # While correct it reads badly.
                    if data[outer_beg - 1] == "*":
                        continue

                text_no_parens = data[outer_beg + 1: outer_end]

                edits.append(Edit(
                    span=(outer_beg, outer_end + 1),
                    content=text_no_parens,
                    content_fail='__ALWAYS_FAIL__',
                ))

            return edits

    class header_clean(EditGenerator):
        """
        Clean headers, ensuring that the headers removed are not used directly or indirectly.

        Note that the `CFLAGS` should be set so missing prototypes error instead of warn:
        With GCC: `-Werror=missing-prototypes`
        """

        @staticmethod
        def _header_guard_from_filename(f: str) -> str:
            return '__%s__' % os.path.basename(f).replace('.', '_').upper()

        @classmethod
        def setup(cls) -> Any:
            # For each file replace `pragma once` with old-style header guard.
            # This is needed so we can remove the header with the knowledge the source file didn't use it indirectly.
            files: List[Tuple[str, str, str, str]] = []
            shared_edit_data = {
                'files': files,
            }
            for f in files_recursive_with_ext(
                    os.path.join(SOURCE_DIR, 'source'),
                    ('.h', '.hh', '.inl', '.hpp', '.hxx'),
            ):
                with open(f, 'r', encoding='utf-8') as fh:
                    data = fh.read()

                for match in re.finditer(r'^[ \t]*#\s*(pragma\s+once)\b', data, flags=re.MULTILINE):
                    header_guard = cls._header_guard_from_filename(f)
                    start, end = match.span()
                    src = data[start:end]
                    dst = (
                        '#ifndef %s\n#define %s' % (header_guard, header_guard)
                    )
                    dst_footer = '\n#endif /* %s */\n' % header_guard
                    files.append((f, src, dst, dst_footer))
                    data = data[:start] + dst + data[end:] + dst_footer
                    with open(f, 'w', encoding='utf-8') as fh:
                        fh.write(data)
                    break
            return shared_edit_data

        @staticmethod
        def teardown(shared_edit_data: Any) -> None:
            files = shared_edit_data['files']
            for f, src, dst, dst_footer in files:
                with open(f, 'r', encoding='utf-8') as fh:
                    data = fh.read()

                data = data.replace(
                    dst, src,
                ).replace(
                    dst_footer, '',
                )
                with open(f, 'w', encoding='utf-8') as fh:
                    fh.write(data)

        @classmethod
        def edit_list_from_file(cls, _source: str, data: str, _shared_edit_data: Any) -> List[Edit]:
            edits = []

            # Remove include.
            for match in re.finditer(r"^(([ \t]*#\s*include\s+\")([^\"]+)(\"[^\n]*\n))", data, flags=re.MULTILINE):
                header_name = match.group(3)
                header_guard = cls._header_guard_from_filename(header_name)
                edits.append(Edit(
                    span=match.span(),
                    content='',  # Remove the header.
                    content_fail='%s__ALWAYS_FAIL__%s' % (match.group(2), match.group(4)),
                    extra_build_args=('-D' + header_guard),
                ))

            return edits

    class use_function_style_cast(EditGenerator):
        """
        Use function call style casts (C++ only).

        Replace:
          (float)(a + b)
        With:
          float(a + b)

        Also support more complex cases involving right hand bracket insertion.

        Replace:
          (float)foo(a + b)
        With:
          float(foo(a + b))
        """
        @staticmethod
        def edit_list_from_file(_source: str, data: str, _shared_edit_data: Any) -> List[Edit]:

            any_number_re = "(" + "|".join(BUILT_IN_NUMERIC_TYPES) + ")"

            edits = []

            # Handle both:
            # - Simple case:  `(float)(a + b)` -> `float(a + b)`.
            # - Complex Case: `(float)foo(a + b) + c` -> `float(foo(a + b)) + c`
            for match in re.finditer(
                    "(\\()" +  # 1st group.
                    any_number_re +  # 2nd group.
                    "(\\))",  # 3rd group.
                    data,
            ):
                beg, end = match.span()