tools: ynl_gen_rst.py: Split library from command line tool

As we'll be using the Netlink specs parser inside a Sphinx
extension, move the library part from the command line parser.

While here, change the code which generates an index file
to parse inputs from both .rst and .yaml extensions. With
that, the tool can easily be tested with:

	tools/net/ynl/pyynl/ynl_gen_rst.py -x -o Documentation/netlink/specs/foo.rst

Without needing to first generate a temp directory with the
rst files.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>

1 files changed, 382 insertions, 0 deletions

diff --git a/tools/net/ynl/pyynl/lib/doc_generator.py b/tools/net/ynl/pyynl/lib/doc_generator.py
new file mode 100644
index 000000000000..80e468086693
--- /dev/null
+++ b/tools/net/ynl/pyynl/lib/doc_generator.py
@@ -0,0 +1,382 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+# -*- coding: utf-8; mode: python -*-
+
+"""
+    Class to auto generate the documentation for Netlink specifications.
+
+    :copyright:  Copyright (C) 2023  Breno Leitao <leitao@debian.org>
+    :license:    GPL Version 2, June 1991 see linux/COPYING for details.
+
+    This class performs extensive parsing to the Linux kernel's netlink YAML
+    spec files, in an effort to avoid needing to heavily mark up the original
+    YAML file.
+
+    This code is split in two classes:
+        1) RST formatters: Use to convert a string to a RST output
+        2) YAML Netlink (YNL) doc generator: Generate docs from YAML data
+"""
+
+from typing import Any, Dict, List
+import os.path
+import sys
+import argparse
+import logging
+import yaml
+
+
+# ==============
+# RST Formatters
+# ==============
+class RstFormatters:
+    SPACE_PER_LEVEL = 4
+
+    @staticmethod
+    def headroom(level: int) -> str:
+        """Return space to format"""
+        return " " * (level * RstFormatters.SPACE_PER_LEVEL)
+
+
+    @staticmethod
+    def bold(text: str) -> str:
+        """Format bold text"""
+        return f"**{text}**"
+
+
+    @staticmethod
+    def inline(text: str) -> str:
+        """Format inline text"""
+        return f"``{text}``"
+
+
+    @staticmethod
+    def sanitize(text: str) -> str:
+        """Remove newlines and multiple spaces"""
+        # This is useful for some fields that are spread across multiple lines
+        return str(text).replace("\n", " ").strip()
+
+
+    def rst_fields(self, key: str, value: str, level: int = 0) -> str:
+        """Return a RST formatted field"""
+        return self.headroom(level) + f":{key}: {value}"
+
+
+    def rst_definition(self, key: str, value: Any, level: int = 0) -> str:
+        """Format a single rst definition"""
+        return self.headroom(level) + key + "\n" + self.headroom(level + 1) + str(value)
+
+
+    def rst_paragraph(self, paragraph: str, level: int = 0) -> str:
+        """Return a formatted paragraph"""
+        return self.headroom(level) + paragraph
+
+
+    def rst_bullet(self, item: str, level: int = 0) -> str:
+        """Return a formatted a bullet"""
+        return self.headroom(level) + f"- {item}"
+
+
+    @staticmethod
+    def rst_subsection(title: str) -> str:
+        """Add a sub-section to the document"""
+        return f"{title}\n" + "-" * len(title)
+
+
+    @staticmethod
+    def rst_subsubsection(title: str) -> str:
+        """Add a sub-sub-section to the document"""
+        return f"{title}\n" + "~" * len(title)
+
+
+    @staticmethod
+    def rst_section(namespace: str, prefix: str, title: str) -> str:
+        """Add a section to the document"""
+        return f".. _{namespace}-{prefix}-{title}:\n\n{title}\n" + "=" * len(title)
+
+
+    @staticmethod
+    def rst_subtitle(title: str) -> str:
+        """Add a subtitle to the document"""
+        return "\n" + "-" * len(title) + f"\n{title}\n" + "-" * len(title) + "\n\n"
+
+
+    @staticmethod
+    def rst_title(title: str) -> str:
+        """Add a title to the document"""
+        return "=" * len(title) + f"\n{title}\n" + "=" * len(title) + "\n\n"
+
+
+    def rst_list_inline(self, list_: List[str], level: int = 0) -> str:
+        """Format a list using inlines"""
+        return self.headroom(level) + "[" + ", ".join(self.inline(i) for i in list_) + "]"
+
+
+    @staticmethod
+    def rst_ref(namespace: str, prefix: str, name: str) -> str:
+        """Add a hyperlink to the document"""
+        mappings = {'enum': 'definition',
+                    'fixed-header': 'definition',
+                    'nested-attributes': 'attribute-set',
+                    'struct': 'definition'}
+        if prefix in mappings:
+            prefix = mappings[prefix]
+        return f":ref:`{namespace}-{prefix}-{name}`"
+
+
+    def rst_header(self) -> str:
+        """The headers for all the auto generated RST files"""
+        lines = []
+
+        lines.append(self.rst_paragraph(".. SPDX-License-Identifier: GPL-2.0"))
+        lines.append(self.rst_paragraph(".. NOTE: This document was auto-generated.\n\n"))
+
+        return "\n".join(lines)
+
+
+    @staticmethod
+    def rst_toctree(maxdepth: int = 2) -> str:
+        """Generate a toctree RST primitive"""
+        lines = []
+
+        lines.append(".. toctree::")
+        lines.append(f"   :maxdepth: {maxdepth}\n\n")
+
+        return "\n".join(lines)
+
+
+    @staticmethod
+    def rst_label(title: str) -> str:
+        """Return a formatted label"""
+        return f".. _{title}:\n\n"
+
+# =======
+# Parsers
+# =======
+class YnlDocGenerator:
+
+    fmt = RstFormatters()
+
+    def parse_mcast_group(self, mcast_group: List[Dict[str, Any]]) -> str:
+        """Parse 'multicast' group list and return a formatted string"""
+        lines = []
+        for group in mcast_group:
+            lines.append(self.fmt.rst_bullet(group["name"]))
+
+        return "\n".join(lines)
+
+
+    def parse_do(self, do_dict: Dict[str, Any], level: int = 0) -> str:
+        """Parse 'do' section and return a formatted string"""
+        lines = []
+        for key in do_dict.keys():
+            lines.append(self.fmt.rst_paragraph(self.fmt.bold(key), level + 1))
+            if key in ['request', 'reply']:
+                lines.append(self.parse_do_attributes(do_dict[key], level + 1) + "\n")
+            else:
+                lines.append(self.fmt.headroom(level + 2) + do_dict[key] + "\n")
+
+        return "\n".join(lines)
+
+
+    def parse_do_attributes(self, attrs: Dict[str, Any], level: int = 0) -> str:
+        """Parse 'attributes' section"""
+        if "attributes" not in attrs:
+            return ""
+        lines = [self.fmt.rst_fields("attributes", self.fmt.rst_list_inline(attrs["attributes"]), level + 1)]
+
+        return "\n".join(lines)
+
+
+    def parse_operations(self, operations: List[Dict[str, Any]], namespace: str) -> str:
+        """Parse operations block"""
+        preprocessed = ["name", "doc", "title", "do", "dump", "flags"]
+        linkable = ["fixed-header", "attribute-set"]
+        lines = []
+
+        for operation in operations:
+            lines.append(self.fmt.rst_section(namespace, 'operation', operation["name"]))
+            lines.append(self.fmt.rst_paragraph(operation["doc"]) + "\n")
+
+            for key in operation.keys():
+                if key in preprocessed:
+                    # Skip the special fields
+                    continue
+                value = operation[key]
+                if key in linkable:
+                    value = self.fmt.rst_ref(namespace, key, value)
+                lines.append(self.fmt.rst_fields(key, value, 0))
+            if 'flags' in operation:
+                lines.append(self.fmt.rst_fields('flags', self.fmt.rst_list_inline(operation['flags'])))
+
+            if "do" in operation:
+                lines.append(self.fmt.rst_paragraph(":do:", 0))
+                lines.append(self.parse_do(operation["do"], 0))
+            if "dump" in operation:
+                lines.append(self.fmt.rst_paragraph(":dump:", 0))
+                lines.append(self.parse_do(operation["dump"], 0))
+
+            # New line after fields
+            lines.append("\n")
+
+        return "\n".join(lines)
+
+
+    def parse_entries(self, entries: List[Dict[str, Any]], level: int) -> str:
+        """Parse a list of entries"""
+        ignored = ["pad"]
+        lines = []
+        for entry in entries:
+            if isinstance(entry, dict):
+                # entries could be a list or a dictionary
+                field_name = entry.get("name", "")
+                if field_name in ignored:
+                    continue
+                type_ = entry.get("type")
+                if type_:
+                    field_name += f" ({self.fmt.inline(type_)})"
+                lines.append(
+                    self.fmt.rst_fields(field_name, self.fmt.sanitize(entry.get("doc", "")), level)
+                )
+            elif isinstance(entry, list):
+                lines.append(self.fmt.rst_list_inline(entry, level))
+            else:
+                lines.append(self.fmt.rst_bullet(self.fmt.inline(self.fmt.sanitize(entry)), level))
+
+        lines.append("\n")
+        return "\n".join(lines)
+
+
+    def parse_definitions(self, defs: Dict[str, Any], namespace: str) -> str:
+        """Parse definitions section"""
+        preprocessed = ["name", "entries", "members"]
+        ignored = ["render-max"]  # This is not printed
+        lines = []
+
+        for definition in defs:
+            lines.append(self.fmt.rst_section(namespace, 'definition', definition["name"]))
+            for k in definition.keys():
+                if k in preprocessed + ignored:
+                    continue
+                lines.append(self.fmt.rst_fields(k, self.fmt.sanitize(definition[k]), 0))
+
+            # Field list needs to finish with a new line
+            lines.append("\n")
+            if "entries" in definition:
+                lines.append(self.fmt.rst_paragraph(":entries:", 0))
+                lines.append(self.parse_entries(definition["entries"], 1))
+            if "members" in definition:
+                lines.append(self.fmt.rst_paragraph(":members:", 0))
+                lines.append(self.parse_entries(definition["members"], 1))
+
+        return "\n".join(lines)
+
+
+    def parse_attr_sets(self, entries: List[Dict[str, Any]], namespace: str) -> str:
+        """Parse attribute from attribute-set"""
+        preprocessed = ["name", "type"]
+        linkable = ["enum", "nested-attributes", "struct", "sub-message"]
+        ignored = ["checks"]
+        lines = []
+
+        for entry in entries:
+            lines.append(self.fmt.rst_section(namespace, 'attribute-set', entry["name"]))
+            for attr in entry["attributes"]:
+                type_ = attr.get("type")
+                attr_line = attr["name"]
+                if type_:
+                    # Add the attribute type in the same line
+                    attr_line += f" ({self.fmt.inline(type_)})"
+
+                lines.append(self.fmt.rst_subsubsection(attr_line))
+
+                for k in attr.keys():
+                    if k in preprocessed + ignored:
+                        continue
+                    if k in linkable:
+                        value = self.fmt.rst_ref(namespace, k, attr[k])
+                    else:
+                        value = self.fmt.sanitize(attr[k])
+                    lines.append(self.fmt.rst_fields(k, value, 0))
+                lines.append("\n")
+
+        return "\n".join(lines)
+
+
+    def parse_sub_messages(self, entries: List[Dict[str, Any]], namespace: str) -> str:
+        """Parse sub-message definitions"""
+        lines = []
+
+        for entry in entries:
+            lines.append(self.fmt.rst_section(namespace, 'sub-message', entry["name"]))
+            for fmt in entry["formats"]:
+                value = fmt["value"]
+
+                lines.append(self.fmt.rst_bullet(self.fmt.bold(value)))
+                for attr in ['fixed-header', 'attribute-set']:
+                    if attr in fmt:
+                        lines.append(self.fmt.rst_fields(attr,
+                                                self.fmt.rst_ref(namespace, attr, fmt[attr]),
+                                                1))
+                lines.append("\n")
+
+        return "\n".join(lines)
+
+
+    def parse_yaml(self, obj: Dict[str, Any]) -> str:
+        """Format the whole YAML into a RST string"""
+        lines = []
+
+        # Main header
+
+        family = obj['name']
+
+        lines.append(self.fmt.rst_header())
+        lines.append(self.fmt.rst_label("netlink-" + family))
+
+        title = f"Family ``{family}`` netlink specification"
+        lines.append(self.fmt.rst_title(title))
+        lines.append(self.fmt.rst_paragraph(".. contents:: :depth: 3\n"))
+
+        if "doc" in obj:
+            lines.append(self.fmt.rst_subtitle("Summary"))
+            lines.append(self.fmt.rst_paragraph(obj["doc"], 0))
+
+        # Operations
+        if "operations" in obj:
+            lines.append(self.fmt.rst_subtitle("Operations"))
+            lines.append(self.parse_operations(obj["operations"]["list"], family))
+
+        # Multicast groups
+        if "mcast-groups" in obj:
+            lines.append(self.fmt.rst_subtitle("Multicast groups"))
+            lines.append(self.parse_mcast_group(obj["mcast-groups"]["list"]))
+
+        # Definitions
+        if "definitions" in obj:
+            lines.append(self.fmt.rst_subtitle("Definitions"))
+            lines.append(self.parse_definitions(obj["definitions"], family))
+
+        # Attributes set
+        if "attribute-sets" in obj:
+            lines.append(self.fmt.rst_subtitle("Attribute sets"))
+            lines.append(self.parse_attr_sets(obj["attribute-sets"], family))
+
+        # Sub-messages
+        if "sub-messages" in obj:
+            lines.append(self.fmt.rst_subtitle("Sub-messages"))
+            lines.append(self.parse_sub_messages(obj["sub-messages"], family))
+
+        return "\n".join(lines)
+
+
+    # Main functions
+    # ==============
+
+
+    def parse_yaml_file(self, filename: str) -> str:
+        """Transform the YAML specified by filename into an RST-formatted string"""
+        with open(filename, "r", encoding="utf-8") as spec_file:
+            yaml_data = yaml.safe_load(spec_file)
+            content = self.parse_yaml(yaml_data)
+
+        return content