scripts/kernel-doc.py: move regex methods to a separate file

In preparation for letting kerneldoc Sphinx extension to import
Python libraries, move regex ancillary classes to a separate
file.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/64f96b6744435b51894bb4ab7612851d9d054190.1744106241.git.mchehab+huawei@kernel.org

1 files changed, 5 insertions, 218 deletions

diff --git a/scripts/kernel-doc.py b/scripts/kernel-doc.py
index fb96d42d287c..7f00c8c86a78 100755
--- a/scripts/kernel-doc.py
+++ b/scripts/kernel-doc.py
@@ -110,228 +110,15 @@ from pprint import pformat
 
 from dateutil import tz
 
-# Local cache for regular expressions
-re_cache = {}
+# Import Python modules
 
+LIB_DIR = "lib/kdoc"
+SRC_DIR = os.path.dirname(os.path.realpath(__file__))
 
-class Re:
-    """
-    Helper class to simplify regex declaration and usage,
-
-    It calls re.compile for a given pattern. It also allows adding
-    regular expressions and define sub at class init time.
-
-    Regular expressions can be cached via an argument, helping to speedup
-    searches.
-    """
-
-    def _add_regex(self, string, flags):
-        if string in re_cache:
-            self.regex = re_cache[string]
-        else:
-            self.regex = re.compile(string, flags=flags)
-
-            if self.cache:
-                re_cache[string] = self.regex
-
-    def __init__(self, string, cache=True, flags=0):
-        self.cache = cache
-        self.last_match = None
-
-        self._add_regex(string, flags)
-
-    def __str__(self):
-        return self.regex.pattern
-
-    def __add__(self, other):
-        return Re(str(self) + str(other), cache=self.cache or other.cache,
-                  flags=self.regex.flags | other.regex.flags)
-
-    def match(self, string):
-        self.last_match = self.regex.match(string)
-        return self.last_match
-
-    def search(self, string):
-        self.last_match = self.regex.search(string)
-        return self.last_match
-
-    def findall(self, string):
-        return self.regex.findall(string)
-
-    def split(self, string):
-        return self.regex.split(string)
-
-    def sub(self, sub, string, count=0):
-        return self.regex.sub(sub, string, count=count)
-
-    def group(self, num):
-        return self.last_match.group(num)
-
-class NestedMatch:
-    """
-    Finding nested delimiters is hard with regular expressions. It is
-    even harder on Python with its normal re module, as there are several
-    advanced regular expressions that are missing.
-
-    This is the case of this pattern:
-
-            '\\bSTRUCT_GROUP(\\(((?:(?>[^)(]+)|(?1))*)\\))[^;]*;'
-
-    which is used to properly match open/close parenthesis of the
-    string search STRUCT_GROUP(),
-
-    Add a class that counts pairs of delimiters, using it to match and
-    replace nested expressions.
-
-    The original approach was suggested by:
-        https://stackoverflow.com/questions/5454322/python-how-to-match-nested-parentheses-with-regex
-
-    Although I re-implemented it to make it more generic and match 3 types
-    of delimiters. The logic checks if delimiters are paired. If not, it
-    will ignore the search string.
-    """
-
-    # TODO:
-    # Right now, regular expressions to match it are defined only up to
-    #       the start delimiter, e.g.:
-    #
-    #       \bSTRUCT_GROUP\(
-    #
-    # is similar to: STRUCT_GROUP\((.*)\)
-    # except that the content inside the match group is delimiter's aligned.
-    #
-    # The content inside parenthesis are converted into a single replace
-    # group (e.g. r`\1').
-    #
-    # It would be nice to change such definition to support multiple
-    # match groups, allowing a regex equivalent to.
-    #
-    #   FOO\((.*), (.*), (.*)\)
-    #
-    # it is probably easier to define it not as a regular expression, but
-    # with some lexical definition like:
-    #
-    #   FOO(arg1, arg2, arg3)
-
-
-    DELIMITER_PAIRS = {
-        '{': '}',
-        '(': ')',
-        '[': ']',
-    }
-
-    RE_DELIM = re.compile(r'[\{\}\[\]\(\)]')
-
-    def _search(self, regex, line):
-        """
-        Finds paired blocks for a regex that ends with a delimiter.
-
-        The suggestion of using finditer to match pairs came from:
-        https://stackoverflow.com/questions/5454322/python-how-to-match-nested-parentheses-with-regex
-        but I ended using a different implementation to align all three types
-        of delimiters and seek for an initial regular expression.
-
-        The algorithm seeks for open/close paired delimiters and place them
-        into a stack, yielding a start/stop position of each match  when the
-        stack is zeroed.
-
-        The algorithm shoud work fine for properly paired lines, but will
-        silently ignore end delimiters that preceeds an start delimiter.
-        This should be OK for kernel-doc parser, as unaligned delimiters
-        would cause compilation errors. So, we don't need to rise exceptions
-        to cover such issues.
-        """
-
-        stack = []
-
-        for match_re in regex.finditer(line):
-            start = match_re.start()
-            offset = match_re.end()
-
-            d = line[offset -1]
-            if d not in self.DELIMITER_PAIRS:
-                continue
-
-            end = self.DELIMITER_PAIRS[d]
-            stack.append(end)
-
-            for match in self.RE_DELIM.finditer(line[offset:]):
-                pos = match.start() + offset
-
-                d = line[pos]
-
-                if d in self.DELIMITER_PAIRS:
-                    end = self.DELIMITER_PAIRS[d]
-
-                    stack.append(end)
-                    continue
-
-                # Does the end delimiter match what it is expected?
-                if stack and d == stack[-1]:
-                    stack.pop()
-
-                    if not stack:
-                        yield start, offset, pos + 1
-                        break
-
-    def search(self, regex, line):
-        """
-        This is similar to re.search:
-
-        It matches a regex that it is followed by a delimiter,
-        returning occurrences only if all delimiters are paired.
-        """
-
-        for t in self._search(regex, line):
-
-            yield line[t[0]:t[2]]
-
-    def sub(self, regex, sub, line, count=0):
-        """
-        This is similar to re.sub:
-
-        It matches a regex that it is followed by a delimiter,
-        replacing occurrences only if all delimiters are paired.
-
-        if r'\1' is used, it works just like re: it places there the
-        matched paired data with the delimiter stripped.
-
-        If count is different than zero, it will replace at most count
-        items.
-        """
-        out = ""
-
-        cur_pos = 0
-        n = 0
-
-        found = False
-        for start, end, pos in self._search(regex, line):
-            out += line[cur_pos:start]
-
-            # Value, ignoring start/end delimiters
-            value = line[end:pos - 1]
-
-            # replaces \1 at the sub string, if \1 is used there
-            new_sub = sub
-            new_sub = new_sub.replace(r'\1', value)
-
-            out += new_sub
-
-            # Drop end ';' if any
-            if line[pos] == ';':
-                pos += 1
-
-            cur_pos = pos
-            n += 1
-
-            if count and count >= n:
-                break
+sys.path.insert(0, os.path.join(SRC_DIR, LIB_DIR))
 
-        # Append the remaining string
-        l = len(line)
-        out += line[cur_pos:l]
+from kdoc_re import Re, NestedMatch
 
-        return out
 
 #
 # Regular expressions used to parse kernel-doc markups at KernelDoc class.