docs: integrate mkdocs into repository

docs/material/plugins/blog/structure/__init__.py

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+# #
+#   Copyright (c) 2025 Aetherinox
+#
+#   Permission is hereby granted, free of charge, to any person obtaining a copy
+#   of this software and associated documentation files (the "Software"), to
+#   deal in the Software without restriction, including without limitation the
+#   rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+#   sell copies of the Software, and to permit persons to whom the Software is
+#   furnished to do so, subject to the following conditions:
+#
+#   The above copyright notice and this permission notice shall be included in
+#   all copies or substantial portions of the Software.
+#
+#   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+#   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+#   FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+#   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+#   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+#   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+#   IN THE SOFTWARE.
+# #
+
+from __future__ import annotations
+
+import logging
+import os
+import yaml
+
+from copy import copy
+from markdown import Markdown
+from material.plugins.blog.author import Author
+from mkdocs.config.defaults import MkDocsConfig
+from mkdocs.exceptions import PluginError
+from mkdocs.structure.files import File, Files
+from mkdocs.structure.nav import Section
+from mkdocs.structure.pages import Page, _RelativePathTreeprocessor
+from mkdocs.structure.toc import get_toc
+from mkdocs.utils.meta import YAML_RE
+from re import Match
+from yaml import SafeLoader
+
+from .config import PostConfig
+from .markdown import ExcerptTreeprocessor
+
+# -----------------------------------------------------------------------------
+# Classes
+# -----------------------------------------------------------------------------
+
+# Post
+class Post(Page):
+
+    # Initialize post - posts are never listed in the navigation, which is why
+    # they will never include a title that was manually set, so we can omit it
+    def __init__(self, file: File, config: MkDocsConfig):
+        super().__init__(None, file, config)
+
+        # Resolve path relative to docs directory
+        docs = os.path.relpath(config.docs_dir)
+        path = os.path.relpath(file.abs_src_path, docs)
+
+        # Read contents and metadata immediately
+        with open(file.abs_src_path, encoding = "utf-8") as f:
+            self.markdown = f.read()
+
+            # Sadly, MkDocs swallows any exceptions that occur during parsing.
+            # Since we want to provide the best possible user experience, we
+            # need to catch errors early and display them nicely. We decided to
+            # drop support for MkDocs' MultiMarkdown syntax, because it is not
+            # correctly implemented anyway. When using MultiMarkdown syntax, all
+            # date formats are returned as strings and list are not properly
+            # supported. Thus, we just use the relevants parts of `get_data`.
+            match: Match = YAML_RE.match(self.markdown)
+            if not match:
+                raise PluginError(
+                    f"Error reading metadata of post '{path}' in '{docs}':\n"
+                    f"Expected metadata to be defined but found nothing"
+                )
+
+            # Extract metadata and parse as YAML
+            try:
+                self.meta = yaml.load(match.group(1), SafeLoader) or {}
+                self.markdown = self.markdown[match.end():].lstrip("\n")
+
+            # The post's metadata could not be parsed because of a syntax error,
+            # which we display to the author with a nice error message
+            except Exception as e:
+                raise PluginError(
+                    f"Error reading metadata of post '{path}' in '{docs}':\n"
+                    f"{e}"
+                )
+
+        # Initialize post configuration, but remove all keys that this plugin
+        # doesn't care about, or they will be reported as invalid configuration
+        self.config: PostConfig = PostConfig(file.abs_src_path)
+        self.config.load_dict({
+            key: self.meta[key] for key in (
+                set(self.meta.keys()) &
+                set(self.config.keys())
+            )
+        })
+
+        # Validate configuration and throw if errors occurred
+        errors, warnings = self.config.validate()
+        for _, w in warnings:
+            log.warning(w)
+        for k, e in errors:
+            raise PluginError(
+                f"Error reading metadata '{k}' of post '{path}' in '{docs}':\n"
+                f"{e}"
+            )
+
+        # Excerpts are subsets of posts that are used in pages like archive and
+        # category views. They are not rendered as standalone pages, but are
+        # rendered in the context of a view. Each post has a dedicated excerpt
+        # instance which is reused when rendering views.
+        self.excerpt: Excerpt = None
+
+        # Initialize authors and actegories
+        self.authors: list[Author] = []
+        self.categories: list[Category] = []
+
+        # Ensure template is set or use default
+        self.meta.setdefault("template", "blog-post.html")
+
+        # Ensure template hides navigation
+        self.meta["hide"] = self.meta.get("hide", [])
+        if "navigation" not in self.meta["hide"]:
+            self.meta["hide"].append("navigation")
+
+    # The contents and metadata were already read in the constructor (and not
+    # in `read_source` as for pages), so this function must be set to a no-op
+    def read_source(self, config: MkDocsConfig):
+        pass
+
+# -----------------------------------------------------------------------------
+
+# Excerpt
+class Excerpt(Page):
+
+    # Initialize an excerpt for the given post - we create the Markdown parser
+    # when intitializing the excerpt in order to improve rendering performance
+    # for excerpts, as they are reused across several different views, because
+    # posts might be referenced from multiple different locations
+    def __init__(self, post: Post, config: MkDocsConfig, files: Files):
+        self.file = copy(post.file)
+        self.post = post
+
+        # Set canonical URL, or we can't print excerpts when debugging the
+        # blog plugin, as the `abs_url` property would be missing
+        self._set_canonical_url(config.site_url)
+
+        # Initialize configuration and metadata
+        self.config = post.config
+        self.meta   = post.meta
+
+        # Initialize authors and categories - note that views usually contain
+        # subsets of those lists, which is why we need to manage them here
+        self.authors: list[Author] = []
+        self.categories: list[Category] = []
+
+        # Initialize content after separator - allow template authors to render
+        # posts inline or to provide a link to the post's page
+        self.more = None
+
+        # Initialize parser - note that we need to patch the configuration,
+        # more specifically the table of contents extension
+        config = _patch(config)
+        self.md = Markdown(
+            extensions = config.markdown_extensions,
+            extension_configs = config.mdx_configs,
+        )
+
+        # Register excerpt tree processor - this processor resolves anchors to
+        # posts from within views, so they point to the correct location
+        self.md.treeprocessors.register(
+            ExcerptTreeprocessor(post),
+            "excerpt",
+            0
+        )
+
+        # Register relative path tree processor - this processor resolves links
+        # to other pages and assets, and is used by MkDocs itself
+        self.md.treeprocessors.register(
+            _RelativePathTreeprocessor(self.file, files, config),
+            "relpath",
+            1
+        )
+
+    # Render an excerpt of the post on the given page - note that this is not
+    # thread-safe because excerpts are shared across views, as it cuts down on
+    # the cost of initialization. However, if in the future, we decide to render
+    # posts and views concurrently, we must change this behavior.
+    def render(self, page: Page, separator: str):
+        self.file.url = page.url
+
+        # Retrieve excerpt tree processor and set page as base
+        at = self.md.treeprocessors.get_index_for_name("excerpt")
+        processor: ExcerptTreeprocessor = self.md.treeprocessors[at]
+        processor.base = page
+
+        # Ensure that the excerpt includes a title in its content, since the
+        # title is linked to the post when rendering - see https://t.ly/5Gg2F
+        self.markdown = self.post.markdown
+        if not self.post._title_from_render:
+            self.markdown = "\n\n".join([f"# {self.post.title}", self.markdown])
+
+        # Convert Markdown to HTML and extract excerpt
+        self.content = self.md.convert(self.markdown)
+        self.content, *more = self.content.split(separator, 1)
+        if more:
+            self.more = more[0]
+
+        # Extract table of contents and reset post URL - if we wouldn't reset
+        # the excerpt URL, linking to the excerpt from the view would not work
+        self.toc = get_toc(getattr(self.md, "toc_tokens", []))
+        self.file.url = self.post.url
+
+# -----------------------------------------------------------------------------
+
+# View
+class View(Page):
+
+    # Parent view
+    parent: View | Section
+
+    # Initialize view
+    def __init__(self, name: str | None, file: File, config: MkDocsConfig):
+        super().__init__(None, file, config)
+
+        # Initialize name of the view - note that views never pass a title to
+        # the parent constructor, so the author can always override the title
+        # that is used for rendering. However, for some purposes, like for
+        # example sorting, we need something to compare.
+        self.name = name
+
+        # Initialize posts and views
+        self.posts: list[Post] = []
+        self.views: list[View] = []
+
+        # Initialize pages for pagination
+        self.pages: list[View] = []
+
+    # Set necessary metadata
+    def read_source(self, config: MkDocsConfig):
+        super().read_source(config)
+
+        # Ensure template is set or use default
+        self.meta.setdefault("template", "blog.html")
+
+# -----------------------------------------------------------------------------
+
+# Archive view
+class Archive(View):
+    pass
+
+# -----------------------------------------------------------------------------
+
+# Category view
+class Category(View):
+    pass
+
+# -----------------------------------------------------------------------------
+# Helper functions
+# -----------------------------------------------------------------------------
+
+# Patch configuration
+def _patch(config: MkDocsConfig):
+    config = copy(config)
+
+    # Copy parts of configuration that needs to be patched
+    config.validation          = copy(config.validation)
+    config.validation.links    = copy(config.validation.links)
+    config.markdown_extensions = copy(config.markdown_extensions)
+    config.mdx_configs         = copy(config.mdx_configs)
+
+    # Make sure that the author did not add another instance of the table of
+    # contents extension to the configuration, as this leads to weird behavior
+    if "markdown.extensions.toc" in config.markdown_extensions:
+        config.markdown_extensions.remove("markdown.extensions.toc")
+
+    # In order to render excerpts for posts, we need to make sure that the
+    # table of contents extension is appropriately configured
+    config.mdx_configs["toc"] = {
+        **config.mdx_configs.get("toc", {}),
+        **{
+            "anchorlink": True,        # Render headline as clickable
+            "baselevel": 2,            # Render h1 as h2 and so forth
+            "permalink": False,        # Remove permalinks
+            "toc_depth": 2             # Remove everything below h2
+        }
+    }
+
+    # Additionally, we disable link validation when rendering excerpts, because
+    # invalid links have already been reported when rendering the page
+    links = config.validation.links
+    links.not_found = logging.DEBUG
+    links.absolute_links = logging.DEBUG
+    links.unrecognized_links = logging.DEBUG
+
+    # Return patched configuration
+    return config
+
+# -----------------------------------------------------------------------------
+# Data
+# -----------------------------------------------------------------------------
+
+# Set up logging
+log = logging.getLogger("mkdocs.material.blog")