linux/scripts/lib/kdoc/kdoc_output.py

#!/usr/bin/env python3
# SPDX-License-Identifier: GPL-2.0
# Copyright(c) 2025: Mauro Carvalho Chehab <mchehab@kernel.org>.
#
# pylint: disable=C0301,R0911,R0912,R0913,R0914,R0915,R0917

# TODO: implement warning filtering

"""
Implement output filters to print kernel-doc documentation.

The implementation uses a virtual base class (OutputFormat) which
contains a dispatches to virtual methods, and some code to filter
out output messages.

The actual implementation is done on one separate class per each type
of output. Currently, there are output classes for ReST and man/troff.
"""

import os
import re
from datetime import datetime

from dateutil import tz

from kdoc_parser import KernelDoc, type_param
from kdoc_re import Re


function_pointer = Re(r"([^\(]*\(\*)\s*\)\s*\(([^\)]*)\)", cache=False)

# match expressions used to find embedded type information
type_constant = Re(r"\b``([^\`]+)``\b", cache=False)
type_constant2 = Re(r"\%([-_*\w]+)", cache=False)
type_func = Re(r"(\w+)\(\)", cache=False)
type_param_ref = Re(r"([\!~\*]?)\@(\w*((\.\w+)|(->\w+))*(\.\.\.)?)", cache=False)

# Special RST handling for func ptr params
type_fp_param = Re(r"\@(\w+)\(\)", cache=False)

# Special RST handling for structs with func ptr params
type_fp_param2 = Re(r"\@(\w+->\S+)\(\)", cache=False)

type_env = Re(r"(\$\w+)", cache=False)
type_enum = Re(r"\&(enum\s*([_\w]+))", cache=False)
type_struct = Re(r"\&(struct\s*([_\w]+))", cache=False)
type_typedef = Re(r"\&(typedef\s*([_\w]+))", cache=False)
type_union = Re(r"\&(union\s*([_\w]+))", cache=False)
type_member = Re(r"\&([_\w]+)(\.|->)([_\w]+)", cache=False)
type_fallback = Re(r"\&([_\w]+)", cache=False)
type_member_func = type_member + Re(r"\(\)", cache=False)


class OutputFormat:
    # output mode.
    OUTPUT_ALL          = 0 # output all symbols and doc sections
    OUTPUT_INCLUDE      = 1 # output only specified symbols
    OUTPUT_EXPORTED     = 2 # output exported symbols
    OUTPUT_INTERNAL     = 3 # output non-exported symbols

    # Virtual member to be overriden at the  inherited classes
    highlights = []

    def __init__(self):
        """Declare internal vars and set mode to OUTPUT_ALL"""

        self.out_mode = self.OUTPUT_ALL
        self.enable_lineno = None
        self.nosymbol = {}
        self.symbol = None
        self.function_table = set()
        self.config = None
        self.no_doc_sections = False

        self.data = ""

    def set_config(self, config):
        self.config = config

    def set_filter(self, export, internal, symbol, nosymbol, function_table,
                   enable_lineno, no_doc_sections):
        """
        Initialize filter variables according with the requested mode.

        Only one choice is valid between export, internal and symbol.

        The nosymbol filter can be used on all modes.
        """

        self.enable_lineno = enable_lineno
        self.no_doc_sections = no_doc_sections

        if symbol:
            self.out_mode = self.OUTPUT_INCLUDE
            function_table = symbol
        elif export:
            self.out_mode = self.OUTPUT_EXPORTED
        elif internal:
            self.out_mode = self.OUTPUT_INTERNAL
        else:
            self.out_mode = self.OUTPUT_ALL

        if nosymbol:
            self.nosymbol = set(nosymbol)

        if function_table:
            self.function_table = function_table

    def highlight_block(self, block):
        """
        Apply the RST highlights to a sub-block of text.
        """

        for r, sub in self.highlights:
            block = r.sub(sub, block)

        return block

    def check_doc(self, name):
        """Check if DOC should be output"""

        if self.no_doc_sections:
            return False

        if self.out_mode == self.OUTPUT_ALL:
            return True

        if self.out_mode == self.OUTPUT_INCLUDE:
            if name in self.nosymbol:
                return False

            if name in self.function_table:
                return True

        return False

    def check_declaration(self, dtype, name):
        if name in self.nosymbol:
            return False

        if self.out_mode == self.OUTPUT_ALL:
            return True

        if self.out_mode in [self.OUTPUT_INCLUDE, self.OUTPUT_EXPORTED]:
            if name in self.function_table:
                return True

        if self.out_mode == self.OUTPUT_INTERNAL:
            if dtype != "function":
                return True

            if name not in self.function_table:
                return True

        return False

    def check_function(self, fname, name, args):
        return True

    def check_enum(self, fname, name, args):
        return True

    def check_typedef(self, fname, name, args):
        return True

    def msg(self, fname, name, args):
        self.data = ""

        dtype = args.get('type', "")

        if dtype == "doc":
            self.out_doc(fname, name, args)
            return self.data

        if not self.check_declaration(dtype, name):
            return self.data

        if dtype == "function":
            self.out_function(fname, name, args)
            return self.data

        if dtype == "enum":
            self.out_enum(fname, name, args)
            return self.data

        if dtype == "typedef":
            self.out_typedef(fname, name, args)
            return self.data

        if dtype in ["struct", "union"]:
            self.out_struct(fname, name, args)
            return self.data

        # Warn if some type requires an output logic
        self.config.log.warning("doesn't now how to output '%s' block",
                                dtype)

        return None

    # Virtual methods to be overridden by inherited classes
    def out_doc(self, fname, name, args):
        pass

    def out_function(self, fname, name, args):
        pass

    def out_enum(self, fname, name, args):
        pass

    def out_typedef(self, fname, name, args):
        pass

    def out_struct(self, fname, name, args):
        pass


class RestFormat(OutputFormat):
    # """Consts and functions used by ReST output"""

    highlights = [
        (type_constant, r"``\1``"),
        (type_constant2, r"``\1``"),

        # Note: need to escape () to avoid func matching later
        (type_member_func, r":c:type:`\1\2\3\\(\\) <\1>`"),
        (type_member, r":c:type:`\1\2\3 <\1>`"),
        (type_fp_param, r"**\1\\(\\)**"),
        (type_fp_param2, r"**\1\\(\\)**"),
        (type_func, r"\1()"),
        (type_enum, r":c:type:`\1 <\2>`"),
        (type_struct, r":c:type:`\1 <\2>`"),
        (type_typedef, r":c:type:`\1 <\2>`"),
        (type_union, r":c:type:`\1 <\2>`"),

        # in rst this can refer to any type
        (type_fallback, r":c:type:`\1`"),
        (type_param_ref, r"**\1\2**")
    ]
    blankline = "\n"

    sphinx_literal = Re(r'^[^.].*::$', cache=False)
    sphinx_cblock = Re(r'^\.\.\ +code-block::', cache=False)

    def __init__(self):
        """
        Creates class variables.

        Not really mandatory, but it is a good coding style and makes
        pylint happy.
        """

        super().__init__()
        self.lineprefix = ""

    def print_lineno(self, ln):
        """Outputs a line number"""

        if self.enable_lineno and ln is not None:
            ln += 1
            self.data += f".. LINENO {ln}\n"

    def output_highlight(self, args):
        input_text = args
        output = ""
        in_literal = False
        litprefix = ""
        block = ""

        for line in input_text.strip("\n").split("\n"):

            # If we're in a literal block, see if we should drop out of it.
            # Otherwise, pass the line straight through unmunged.
            if in_literal:
                if line.strip():  # If the line is not blank
                    # If this is the first non-blank line in a literal block,
                    # figure out the proper indent.
                    if not litprefix:
                        r = Re(r'^(\s*)')
                        if r.match(line):
                            litprefix = '^' + r.group(1)
                        else:
                            litprefix = ""

                        output += line + "\n"
                    elif not Re(litprefix).match(line):
                        in_literal = False
                    else:
                        output += line + "\n"
                else:
                    output += line + "\n"

            # Not in a literal block (or just dropped out)
            if not in_literal:
                block += line + "\n"
                if self.sphinx_literal.match(line) or self.sphinx_cblock.match(line):
                    in_literal = True
                    litprefix = ""
                    output += self.highlight_block(block)
                    block = ""

        # Handle any remaining block
        if block:
            output += self.highlight_block(block)

        # Print the output with the line prefix
        for line in output.strip("\n").split("\n"):
            self.data += self.lineprefix + line + "\n"

    def out_section(self, args, out_reference=False):
        """
        Outputs a block section.

        This could use some work; it's used to output the DOC: sections, and
        starts by putting out the name of the doc section itself, but that
        tends to duplicate a header already in the template file.
        """

        sectionlist = args.get('sectionlist', [])
        sections = args.get('sections', {})
        section_start_lines = args.get('section_start_lines', {})

        for section in sectionlist:
            # Skip sections that are in the nosymbol_table
            if section in self.nosymbol:
                continue

            if not self.out_mode == self.OUTPUT_INCLUDE:
                if out_reference:
                    self.data += f".. _{section}:\n\n"

                if not self.symbol:
                    self.data += f'{self.lineprefix}**{section}**\n\n'

            self.print_lineno(section_start_lines.get(section, 0))
            self.output_highlight(sections[section])
            self.data += "\n"
        self.data += "\n"

    def out_doc(self, fname, name, args):
        if not self.check_doc(name):
            return

        self.out_section(args, out_reference=True)

    def out_function(self, fname, name, args):

        oldprefix = self.lineprefix
        signature = ""

        func_macro = args.get('func_macro', False)
        if func_macro:
            signature = args['function']
        else:
            if args.get('functiontype'):
                signature = args['functiontype'] + " "
            signature += args['function'] + " ("

        parameterlist = args.get('parameterlist', [])
        parameterdescs = args.get('parameterdescs', {})
        parameterdesc_start_lines = args.get('parameterdesc_start_lines', {})

        ln = args.get('declaration_start_line', 0)

        count = 0
        for parameter in parameterlist:
            if count != 0:
                signature += ", "
            count += 1
            dtype = args['parametertypes'].get(parameter, "")

            if function_pointer.search(dtype):
                signature += function_pointer.group(1) + parameter + function_pointer.group(3)
            else:
                signature += dtype

        if not func_macro:
            signature += ")"

        self.print_lineno(ln)
        if args.get('typedef') or not args.get('functiontype'):
            self.data += f".. c:macro:: {args['function']}\n\n"

            if args.get('typedef'):
                self.data += "   **Typedef**: "
                self.lineprefix = ""
                self.output_highlight(args.get('purpose', ""))
                self.data += "\n\n**Syntax**\n\n"
                self.data += f"  ``{signature}``\n\n"
            else:
                self.data += f"``{signature}``\n\n"
        else:
            self.data += f".. c:function:: {signature}\n\n"

        if not args.get('typedef'):
            self.print_lineno(ln)
            self.lineprefix = "   "
            self.output_highlight(args.get('purpose', ""))
            self.data += "\n"

        # Put descriptive text into a container (HTML <div>) to help set
        # function prototypes apart
        self.lineprefix = "  "

        if parameterlist:
            self.data += ".. container:: kernelindent\n\n"
            self.data += f"{self.lineprefix}**Parameters**\n\n"

        for parameter in parameterlist:
            parameter_name = Re(r'\[.*').sub('', parameter)
            dtype = args['parametertypes'].get(parameter, "")

            if dtype:
                self.data += f"{self.lineprefix}``{dtype}``\n"
            else:
                self.data += f"{self.lineprefix}``{parameter}``\n"

            self.print_lineno(parameterdesc_start_lines.get(parameter_name, 0))

            self.lineprefix = "    "
            if parameter_name in parameterdescs and \
               parameterdescs[parameter_name] != KernelDoc.undescribed:

                self.output_highlight(parameterdescs[parameter_name])
                self.data += "\n"
            else:
                self.data += f"{self.lineprefix}*undescribed*\n\n"
            self.lineprefix = "  "

        self.out_section(args)
        self.lineprefix = oldprefix

    def out_enum(self, fname, name, args):

        oldprefix = self.lineprefix
        name = args.get('enum', '')
        parameterlist = args.get('parameterlist', [])
        parameterdescs = args.get('parameterdescs', {})
        ln = args.get('declaration_start_line', 0)

        self.data += f"\n\n.. c:enum:: {name}\n\n"

        self.print_lineno(ln)
        self.lineprefix = "  "
        self.output_highlight(args.get('purpose', ''))
        self.data += "\n"

        self.data += ".. container:: kernelindent\n\n"
        outer = self.lineprefix + "  "
        self.lineprefix = outer + "  "
        self.data += f"{outer}**Constants**\n\n"

        for parameter in parameterlist:
            self.data += f"{outer}``{parameter}``\n"

            if parameterdescs.get(parameter, '') != KernelDoc.undescribed:
                self.output_highlight(parameterdescs[parameter])
            else:
                self.data += f"{self.lineprefix}*undescribed*\n\n"
            self.data += "\n"

        self.lineprefix = oldprefix
        self.out_section(args)

    def out_typedef(self, fname, name, args):

        oldprefix = self.lineprefix
        name = args.get('typedef', '')
        ln = args.get('declaration_start_line', 0)

        self.data += f"\n\n.. c:type:: {name}\n\n"

        self.print_lineno(ln)
        self.lineprefix = "   "

        self.output_highlight(args.get('purpose', ''))

        self.data += "\n"

        self.lineprefix = oldprefix
        self.out_section(args)

    def out_struct(self, fname, name, args):

        name = args.get('struct', "")
        purpose = args.get('purpose', "")
        declaration = args.get('definition', "")
        dtype = args.get('type', "struct")
        ln = args.get('declaration_start_line', 0)

        parameterlist = args.get('parameterlist', [])
        parameterdescs = args.get('parameterdescs', {})
        parameterdesc_start_lines = args.get('parameterdesc_start_lines', {})

        self.data += f"\n\n.. c:{dtype}:: {name}\n\n"

        self.print_lineno(ln)

        oldprefix = self.lineprefix
        self.lineprefix += "  "

        self.output_highlight(purpose)
        self.data += "\n"

        self.data += ".. container:: kernelindent\n\n"
        self.data += f"{self.lineprefix}**Definition**::\n\n"

        self.lineprefix = self.lineprefix + "  "

        declaration = declaration.replace("\t", self.lineprefix)

        self.data += f"{self.lineprefix}{dtype} {name}" + ' {' + "\n"
        self.data += f"{declaration}{self.lineprefix}" + "};\n\n"

        self.lineprefix = "  "
        self.data += f"{self.lineprefix}**Members**\n\n"
        for parameter in parameterlist:
            if not parameter or parameter.startswith("#"):
                continue

            parameter_name = parameter.split("[", maxsplit=1)[0]

            if parameterdescs.get(parameter_name) == KernelDoc.undescribed:
                continue

            self.print_lineno(parameterdesc_start_lines.get(parameter_name, 0))

            self.data += f"{self.lineprefix}``{parameter}``\n"

            self.lineprefix = "    "
            self.output_highlight(parameterdescs[parameter_name])
            self.lineprefix = "  "

            self.data += "\n"

        self.data += "\n"

        self.lineprefix = oldprefix
        self.out_section(args)


class ManFormat(OutputFormat):
    """Consts and functions used by man pages output"""

    highlights = (
        (type_constant, r"\1"),
        (type_constant2, r"\1"),
        (type_func, r"\\fB\1\\fP"),
        (type_enum, r"\\fI\1\\fP"),
        (type_struct, r"\\fI\1\\fP"),
        (type_typedef, r"\\fI\1\\fP"),
        (type_union, r"\\fI\1\\fP"),
        (type_param, r"\\fI\1\\fP"),
        (type_param_ref, r"\\fI\1\2\\fP"),
        (type_member, r"\\fI\1\2\3\\fP"),
        (type_fallback, r"\\fI\1\\fP")
    )
    blankline = ""

    def __init__(self):
        """
        Creates class variables.

        Not really mandatory, but it is a good coding style and makes
        pylint happy.
        """

        super().__init__()

        dt = datetime.now()
        if os.environ.get("KBUILD_BUILD_TIMESTAMP", None):
            # use UTC TZ
            to_zone = tz.gettz('UTC')
            dt = dt.astimezone(to_zone)

        self.man_date = dt.strftime("%B %Y")

    def output_highlight(self, block):

        contents = self.highlight_block(block)

        if isinstance(contents, list):
            contents = "\n".join(contents)

        for line in contents.strip("\n").split("\n"):
            line = Re(r"^\s*").sub("", line)

            if line and line[0] == ".":
                self.data += "\\&" + line + "\n"
            else:
                self.data += line + "\n"

    def out_doc(self, fname, name, args):
        module = args.get('module')
        sectionlist = args.get('sectionlist', [])
        sections = args.get('sections', {})

        self.data += f'.TH "{module}" 9 "{module}" "{self.man_date}" "API Manual" LINUX' + "\n"

        for section in sectionlist:
            self.data += f'.SH "{section}"' + "\n"
            self.output_highlight(sections.get(section))

    def out_function(self, fname, name, args):
        """output function in man"""

        parameterlist = args.get('parameterlist', [])
        parameterdescs = args.get('parameterdescs', {})
        sectionlist = args.get('sectionlist', [])
        sections = args.get('sections', {})

        self.data += f'.TH "{args['function']}" 9 "{args['function']}" "{self.man_date}" "Kernel Hacker\'s Manual" LINUX' + "\n"

        self.data += ".SH NAME\n"
        self.data += f"{args['function']} \\- {args['purpose']}\n"

        self.data += ".SH SYNOPSIS\n"
        if args.get('functiontype', ''):
            self.data += f'.B "{args['functiontype']}" {args['function']}' + "\n"
        else:
            self.data += f'.B "{args['function']}' + "\n"

        count = 0
        parenth = "("
        post = ","

        for parameter in parameterlist:
            if count == len(parameterlist) - 1:
                post = ");"

            dtype = args['parametertypes'].get(parameter, "")
            if function_pointer.match(dtype):
                # Pointer-to-function
                self.data += f'".BI "{parenth}{function_pointer.group(1)}" " ") ({function_pointer.group(2)}){post}"' + "\n"
            else:
                dtype = Re(r'([^\*])$').sub(r'\1 ', dtype)

                self.data += f'.BI "{parenth}{dtype}"  "{post}"' + "\n"
            count += 1
            parenth = ""

        if parameterlist:
            self.data += ".SH ARGUMENTS\n"

        for parameter in parameterlist:
            parameter_name = re.sub(r'\[.*', '', parameter)

            self.data += f'.IP "{parameter}" 12' + "\n"
            self.output_highlight(parameterdescs.get(parameter_name, ""))

        for section in sectionlist:
            self.data += f'.SH "{section.upper()}"' + "\n"
            self.output_highlight(sections[section])

    def out_enum(self, fname, name, args):

        name = args.get('enum', '')
        parameterlist = args.get('parameterlist', [])
        sectionlist = args.get('sectionlist', [])
        sections = args.get('sections', {})

        self.data += f'.TH "{args['module']}" 9 "enum {args['enum']}" "{self.man_date}" "API Manual" LINUX' + "\n"

        self.data += ".SH NAME\n"
        self.data += f"enum {args['enum']} \\- {args['purpose']}\n"

        self.data += ".SH SYNOPSIS\n"
        self.data += f"enum {args['enum']}" + " {\n"

        count = 0
        for parameter in parameterlist:
            self.data += f'.br\n.BI "    {parameter}"' + "\n"
            if count == len(parameterlist) - 1:
                self.data += "\n};\n"
            else:
                self.data += ", \n.br\n"

            count += 1

        self.data += ".SH Constants\n"

        for parameter in parameterlist:
            parameter_name = Re(r'\[.*').sub('', parameter)
            self.data += f'.IP "{parameter}" 12' + "\n"
            self.output_highlight(args['parameterdescs'].get(parameter_name, ""))

        for section in sectionlist:
            self.data += f'.SH "{section}"' + "\n"
            self.output_highlight(sections[section])

    def out_typedef(self, fname, name, args):
        module = args.get('module')
        typedef = args.get('typedef')
        purpose = args.get('purpose')
        sectionlist = args.get('sectionlist', [])
        sections = args.get('sections', {})

        self.data += f'.TH "{module}" 9 "{typedef}" "{self.man_date}" "API Manual" LINUX' + "\n"

        self.data += ".SH NAME\n"
        self.data += f"typedef {typedef} \\- {purpose}\n"

        for section in sectionlist:
            self.data += f'.SH "{section}"' + "\n"
            self.output_highlight(sections.get(section))

    def out_struct(self, fname, name, args):
        module = args.get('module')
        struct_type = args.get('type')
        struct_name = args.get('struct')
        purpose = args.get('purpose')
        definition = args.get('definition')
        sectionlist = args.get('sectionlist', [])
        parameterlist = args.get('parameterlist', [])
        sections = args.get('sections', {})
        parameterdescs = args.get('parameterdescs', {})

        self.data += f'.TH "{module}" 9 "{struct_type} {struct_name}" "{self.man_date}" "API Manual" LINUX' + "\n"

        self.data += ".SH NAME\n"
        self.data += f"{struct_type} {struct_name} \\- {purpose}\n"

        # Replace tabs with two spaces and handle newlines
        declaration = definition.replace("\t", "  ")
        declaration = Re(r"\n").sub('"\n.br\n.BI "', declaration)

        self.data += ".SH SYNOPSIS\n"
        self.data += f"{struct_type} {struct_name} " + "{" + "\n.br\n"
        self.data += f'.BI "{declaration}\n' + "};\n.br\n\n"

        self.data += ".SH Members\n"
        for parameter in parameterlist:
            if parameter.startswith("#"):
                continue

            parameter_name = re.sub(r"\[.*", "", parameter)

            if parameterdescs.get(parameter_name) == KernelDoc.undescribed:
                continue

            self.data += f'.IP "{parameter}" 12' + "\n"
            self.output_highlight(parameterdescs.get(parameter_name))

        for section in sectionlist:
            self.data += f'.SH "{section}"' + "\n"
            self.output_highlight(sections.get(section))