Sphinx

# Source code for sphinx.builders

    """Builder superclass for all builders."""

    from __future__ import annotations

    import pickle
    import re
    import time
    from contextlib import nullcontext
    from pathlib import Path
    from typing import TYPE_CHECKING, final

    from docutils import nodes
    from docutils.utils import DependencyList

    from sphinx._cli.util.colour import bold
    from sphinx.deprecation import _deprecation_warning
    from sphinx.environment import (
        CONFIG_CHANGED_REASON,
        CONFIG_OK,
        _CurrentDocument,
    )
    from sphinx.environment.adapters.asset import ImageAdapter
    from sphinx.errors import SphinxError
    from sphinx.locale import __
    from sphinx.util import get_filetype, logging
    from sphinx.util._importer import import_object
    from sphinx.util._pathlib import _StrPathProperty
    from sphinx.util.build_phase import BuildPhase
    from sphinx.util.display import progress_message, status_iterator
    from sphinx.util.docutils import _parse_str_to_doctree
    from sphinx.util.i18n import CatalogRepository, docname_to_domain
    from sphinx.util.osutil import ensuredir, relative_uri, relpath
    from sphinx.util.parallel import (
        ParallelTasks,
        SerialTasks,
        make_chunks,
        parallel_available,
    )

    # side effect: registers roles and directives
    from sphinx import directives  # NoQA: F401  isort:skip
    from sphinx import roles  # NoQA: F401  isort:skip

    if TYPE_CHECKING:
        from collections.abc import Iterable, Sequence, Set
        from gettext import NullTranslations
        from typing import Any, ClassVar, Literal

        from docutils.nodes import Node

        from sphinx.application import Sphinx
        from sphinx.config import Config
        from sphinx.environment import (
            BuildEnvironment,
        )
        from sphinx.events import EventManager
        from sphinx.util.i18n import CatalogInfo
        from sphinx.util.tags import Tags

    logger = logging.getLogger(__name__)

    class Builder:
        """Builds target formats from the reST sources."""

        #: The builder's name.
        #: This is the value used to select builders on the command line.
        name: ClassVar[str] = ''
        #: The builder's output format, or '' if no document output is produced.
        #: This is commonly the file extension, e.g. "html",
        #: though any string value is accepted.
        #: The builder's format string can be used by various components
        #: such as :class:`.SphinxPostTransform` or extensions to determine
        #: their compatibility with the builder.
        format: ClassVar[str] = ''
        #: The message emitted upon successful build completion.
        #: This can be a printf-style template string
        #: with the following keys: ``outdir``, ``project``
        epilog: ClassVar[str] = ''

        #: default translator class for the builder.  This can be overridden by
        #: :py:meth:`~sphinx.application.Sphinx.set_translator`.
        default_translator_class: ClassVar[type[nodes.NodeVisitor]]
        # doctree versioning method
        versioning_method: ClassVar[str] = 'none'
        versioning_compare: ClassVar[bool] = False
        #: Whether it is safe to make parallel :meth:`~.Builder.write_doc` calls.
        allow_parallel: ClassVar[bool] = False
        # support translation
        use_message_catalog: ClassVar[bool] = True

        #: The list of MIME types of image formats supported by the builder.
        #: Image files are searched in the order in which they appear here.
        supported_image_types: ClassVar[list[str]] = []
        #: The builder can produce output documents that may fetch external images when opened.
        supported_remote_images: ClassVar[bool] = False
        #: The file format produced by the builder allows images to be embedded using data-URIs.
        supported_data_uri_images: ClassVar[bool] = False

        phase: BuildPhase = BuildPhase.INITIALIZATION

        srcdir = _StrPathProperty()
        confdir = _StrPathProperty()
        outdir = _StrPathProperty()
        doctreedir = _StrPathProperty()

        def __init__(self, app: Sphinx, env: BuildEnvironment) -> None:
            self.srcdir = app.srcdir
            self.confdir = app.confdir
            self.outdir = app.outdir
            self.doctreedir = app.doctreedir
            ensuredir(self.doctreedir)

            self._app: Sphinx = app
            self.env: BuildEnvironment = env
            self.env.set_versioning_method(self.versioning_method, self.versioning_compare)
            self.events: EventManager = app.events
            self.config: Config = app.config
            self.tags: Tags = app.tags
            self.tags.add(self.format)
            self.tags.add(self.name)
            self.tags.add(f'format_{self.format}')
            self.tags.add(f'builder_{self.name}')
            self._registry = app.registry

            # images that need to be copied over (source -> dest)
            self.images: dict[str, str] = {}
            # basename of images directory
            self.imagedir = ''
            # relative path to image directory from current docname (used at writing docs)
            self.imgpath = ''

            # these get set later
            self.parallel_ok = False
            self.finish_tasks: Any = None

        @property
        def app(self) -> Sphinx:
            cls_module = self.__class__.__module__
            cls_name = self.__class__.__qualname__
            _deprecation_warning(cls_module, f'{cls_name}.app', remove=(11, 0))
            return self._app

        @property
        def _translator(self) -> NullTranslations | None:
            return self._app.translator

        def get_translator_class(self, *args: Any) -> type[nodes.NodeVisitor]:
            """Return a class of translator."""
            return self._registry.get_translator_class(self)

        def create_translator(self, *args: Any) -> nodes.NodeVisitor:
            """Return an instance of translator.

            This method returns an instance of ``default_translator_class`` by default.
            Users can replace the translator class with ``app.set_translator()`` API.
            """
            return self._registry.create_translator(self, *args)

        # helper methods

        def init(self) -> None:
            """Load necessary templates and perform initialization.  The default
            implementation does nothing.
            """
            pass

        def create_template_bridge(self) -> None:
            """Return the template bridge configured."""
            if self.config.template_bridge:
                template_bridge_cls = import_object(
                    self.config.template_bridge,
                    source='template_bridge setting',
                )
                self.templates = template_bridge_cls()
            else:
                from sphinx.jinja2glue import BuiltinTemplateLoader

                self.templates = BuiltinTemplateLoader()

        def get_target_uri(self, docname: str, typ: str | None = None) -> str:
            """Return the target URI for a document name.

            *typ* can be used to qualify the link characteristic for individual
            builders.
            """
            raise NotImplementedError

        def get_relative_uri(self, from_: str, to: str, typ: str | None = None) -> str:
            """Return a relative URI between two source filenames.

            :raises: :exc:`!NoUri` if there's no way to return a sensible URI.
            """
            return relative_uri(
                self.get_target_uri(from_),
                self.get_target_uri(to, typ),
            )

        def get_outdated_docs(self) -> str | Iterable[str]:
            """Return an iterable of output files that are outdated, or a string
            describing what an update build will build.

            If the builder does not output individual files corresponding to
            source files, return a string here.  If it does, return an iterable
            of those files that need to be written.
            """
            raise NotImplementedError

        def get_asset_paths(self) -> list[str]:
            """Return list of paths for assets (ex. templates, CSS, etc.)."""
            return []

        def post_process_images(self, doctree: Node) -> None:
            """Pick the best candidate for all image URIs."""
            images = ImageAdapter(self.env)
            for node in doctree.findall(nodes.image):
                if '?' in node['candidates']:
                    # don't rewrite nonlocal image URIs
                    continue
                if '*' not in node['candidates']:
                    for imgtype in self.supported_image_types:
                        candidate = node['candidates'].get(imgtype, None)
                        if candidate:
                            break
                    else:
                        mimetypes = sorted(node['candidates'])
                        image_uri = images.get_original_image_uri(node['uri'])
                        if mimetypes:
                            logger.warning(
                                __('a suitable image for %s builder not found: %s (%s)'),
                                self.name,
                                mimetypes,
                                image_uri,
                                location=node,
                            )
                        else:
                            logger.warning(
                                __('a suitable image for %s builder not found: %s'),
                                self.name,
                                image_uri,
                                location=node,
                            )
                        continue
                    node['uri'] = candidate
                else:
                    candidate = node['uri']
                if candidate not in self.env.images:
                    # non-existing URI; let it alone
                    continue
                self.images[candidate] = self.env.images[candidate][1]

        # compile po methods

        def compile_catalogs(self, catalogs: set[CatalogInfo], message: str) -> None:
            if not self.config.gettext_auto_build:
                return

            def cat2relpath(cat: CatalogInfo, srcdir: Path = self.srcdir) -> str:
                return Path(relpath(cat.mo_path, srcdir)).as_posix()

            logger.info(bold(__('building [mo]: ')) + message)  # NoQA: G003
            for catalog in status_iterator(
                catalogs,
                __('writing output... '),
                'darkgreen',
                len(catalogs),
                self.config.verbosity,
                stringify_func=cat2relpath,
            ):
                catalog.write_mo(
                    self.config.language, self.config.gettext_allow_fuzzy_translations
                )

        def compile_all_catalogs(self) -> None:
            repo = CatalogRepository(
                self.srcdir,
                self.config.locale_dirs,
                self.config.language,
                self.config.source_encoding,
            )
            message = __('all of %d po files') % len(list(repo.catalogs))
            self.compile_catalogs(set(repo.catalogs), message)

        def compile_specific_catalogs(self, specified_files: Iterable[Path]) -> None:
            env = self.env
            gettext_compact = self.config.gettext_compact

            domains = {
                docname_to_domain(docname, gettext_compact) if docname else None
                for file in specified_files
                if (docname := env.path2doc(file))
            }
            catalogs = set()
            repo = CatalogRepository(
                self.srcdir,
                self.config.locale_dirs,
                self.config.language,
                self.config.source_encoding,
            )
            for catalog in repo.catalogs:
                if catalog.domain in domains and catalog.is_outdated():
                    catalogs.add(catalog)
            message = __('targets for %d po files that are specified') % len(catalogs)
            self.compile_catalogs(catalogs, message)

        # TODO(stephenfin): This would make more sense as 'compile_outdated_catalogs'
        def compile_update_catalogs(self) -> None:
            repo = CatalogRepository(
                self.srcdir,
                self.config.locale_dirs,
                self.config.language,
                self.config.source_encoding,
            )
            catalogs = {c for c in repo.catalogs if c.is_outdated()}
            message = __('targets for %d po files that are out of date') % len(catalogs)
            self.compile_catalogs(catalogs, message)

        # build methods

        @final
        def build_all(self) -> None:
            """Build all source files."""
            self.compile_all_catalogs()

            self.build(None, summary=__('all source files'), method='all')

        @final
        def build_specific(self, filenames: Sequence[Path]) -> None:
            """Only rebuild as much as needed for changes in the *filenames*."""
            docnames: list[str] = []

            filenames = [Path(filename).resolve() for filename in filenames]
            for filename in filenames:
                if not filename.is_file():
                    logger.warning(
                        __('file %r given on command line does not exist, '), filename
                    )
                    continue

                if not filename.is_relative_to(self.srcdir):
                    logger.warning(
                        __(
                            'file %r given on command line is not under the '
                            'source directory, ignoring'
                        ),
                        filename,
                    )
                    continue

                docname = self.env.path2doc(filename)
                if not docname:
                    logger.warning(
                        __(
                            'file %r given on command line is not a valid '
                            'document, ignoring'
                        ),
                        filename,
                    )
                    continue

                docnames.append(docname)

            self.compile_specific_catalogs(filenames)

            self.build(
                docnames,
                summary=__('%d source files given on command line') % len(docnames),
                method='specific',
            )

        @final
        def build_update(self) -> None:
            """Only rebuild what was changed or added since last build."""
            self.compile_update_catalogs()

            to_build = self.get_outdated_docs()
            if isinstance(to_build, str):
                self.build(['__all__'], summary=to_build, method='update')
            else:
                to_build = set(to_build)
                self.build(
                    to_build,
                    summary=__('targets for %d source files that are out of date')
                    % len(to_build),
                    method='update',
                )

        @final
        def build(
            self,
            docnames: Iterable[str] | None,
            summary: str | None = None,
            method: Literal['all', 'specific', 'update'] = 'update',
        ) -> None:
            """Main build method, usually called by a specific ``build_*`` method.

            First updates the environment, and then calls
            :meth:`!write`.
            """
            if summary:
                logger.info(bold(__('building [%s]: ')) + summary, self.name)  # NoQA: G003

            # while reading, collect all warnings from docutils
            with (
                nullcontext()
                if self._app._exception_on_warning
                else logging.pending_warnings()
            ):
                updated_docnames = set(self.read())

            doccount = len(updated_docnames)
            logger.info(bold(__('looking for now-outdated files... ')), nonl=True)
            updated_docnames.update(self.env.check_dependents(self._app, updated_docnames))
            outdated = len(updated_docnames) - doccount
            if outdated:
                logger.info(__('%d found'), outdated)
            else:
                logger.info(__('none found'))

            if updated_docnames:
                # save the environment
                from sphinx.application import ENV_PICKLE_FILENAME

                with (
                    progress_message(__('pickling environment')),
                    open(self.doctreedir / ENV_PICKLE_FILENAME, 'wb') as f,
                ):
                    pickle.dump(self.env, f, pickle.HIGHEST_PROTOCOL)

                # global actions
                self.phase = BuildPhase.CONSISTENCY_CHECK
                with progress_message(__('checking consistency')):
                    self.env.check_consistency()
            else:
                if method == 'update' and not docnames:
                    logger.info(bold(__('no targets are out of date.')))

            self.phase = BuildPhase.RESOLVING

            # filter "docnames" (list of outdated files) by the updated
            # found_docs of the environment; this will remove docs that
            # have since been removed
            if docnames and docnames != ['__all__']:
                docnames = set(docnames) & self.env.found_docs

            # determine if we can write in parallel
            if parallel_available and self._app.parallel > 1 and self.allow_parallel:
                self.parallel_ok = self._app.is_parallel_allowed('write')
            else:
                self.parallel_ok = False

            #  create a task executor to use for misc. "finish-up" tasks
            # if self.parallel_ok:
            #     self.finish_tasks = ParallelTasks(self._app.parallel)
            # else:
            # for now, just execute them serially
            self.finish_tasks = SerialTasks()

            # write all "normal" documents (or everything for some builders)
            self.write(docnames, updated_docnames, method)

            # finish (write static files etc.)
            self.finish()

            # wait for all tasks
            self.finish_tasks.join()

        @final
        def read(self) -> list[str]:
            """(Re-)read all files new or changed since last update.

            Store all environment docnames in the canonical format (ie using SEP as
            a separator in place of os.path.sep).
            """
            logger.info(bold(__('updating environment: ')), nonl=True)

            self.env.find_files(self.config, self)
            updated = self.env.config_status != CONFIG_OK
            added, changed, removed = self.env.get_outdated_files(updated)

            # allow user intervention as well
            for docs in self.events.emit(
                'env-get-outdated', self.env, added, changed, removed
            ):
                changed.update(set(docs) & self.env.found_docs)

            # if files were added or removed, all documents with globbed toctrees
            # must be reread
            if added or removed:
                # ... but not those that already were removed
                changed.update(self.env.glob_toctrees & self.env.found_docs)

            if updated:  # explain the change iff build config status was not ok
                reason = CONFIG_CHANGED_REASON.get(self.env.config_status, '') + (
                    self.env.config_status_extra or ''
                )
                logger.info('[%s] ', reason, nonl=True)

            logger.info(
                __('%s added, %s changed, %s removed'),
                len(added),
                len(changed),
                len(removed),
            )

            # clear all files no longer present
            for docname in removed:
                self.events.emit('env-purge-doc', self.env, docname)
                self.env.clear_doc(docname)

            # read all new and changed files
            docnames = sorted(added | changed)
            # allow changing and reordering the list of docs to read
            self.events.emit('env-before-read-docs', self.env, docnames)

            # check if we should do parallel or serial read
            if parallel_available and self._app.parallel > 1:
                par_ok = self._app.is_parallel_allowed('read')
            else:
                par_ok = False

            if par_ok:
                self._read_parallel(docnames, nproc=self._app.parallel)
            else:
                self._read_serial(docnames)

            if self.config.master_doc not in self.env.all_docs:
                from sphinx.project import EXCLUDE_PATHS
                from sphinx.util.matching import _translate_pattern

                master_doc_path = self.env.doc2path(self.config.master_doc)
                master_doc_canon = master_doc_path.as_posix()
                for pat in EXCLUDE_PATHS:
                    if not re.match(_translate_pattern(pat), master_doc_canon):
                        continue
                    msg = __(
                        'Sphinx is unable to load the master document (%s) '
                        'because it matches a built-in exclude pattern %r. '
                        'Please move your master document to a different location.'
                    )
                    raise SphinxError(msg % (master_doc_path, pat))
                for pat in self.config.exclude_patterns:
                    if not re.match(_translate_pattern(pat), master_doc_canon):
                        continue
                    msg = __(
                        'Sphinx is unable to load the master document (%s) '
                        'because it matches an exclude pattern specified '
                        'in conf.py, %r. '
                        'Please remove this pattern from conf.py.'
                    )
                    raise SphinxError(msg % (master_doc_path, pat))
                if set(self.config.include_patterns) != {'**'} and not any(
                    re.match(_translate_pattern(pat), master_doc_canon)
                    for pat in self.config.include_patterns
                ):
                    msg = __(
                        'Sphinx is unable to load the master document (%s) '
                        'because it is not included in the custom include_patterns = %r. '
                        'Ensure that a pattern in include_patterns matches the '
                        'master document.'
                    )
                    raise SphinxError(msg % (master_doc_path, self.config.include_patterns))
                msg = __(
                    'Sphinx is unable to load the master document (%s). '
                    'The master document must be within the source directory '
                    'or a subdirectory of it.'
                )
                raise SphinxError(msg % master_doc_path)

            for retval in self.events.emit('env-updated', self.env):
                if retval is not None:
                    docnames.extend(retval)

            # workaround: marked as okay to call builder.read() twice in same process
            self.env.config_status = CONFIG_OK

            return sorted(docnames)

        def _read_serial(self, docnames: list[str]) -> None:
            for docname in status_iterator(
                docnames,
                __('reading sources... '),
                'purple',
                len(docnames),
                self.config.verbosity,
            ):
                # remove all inventory entries for that file
                self.events.emit('env-purge-doc', self.env, docname)
                self.env.clear_doc(docname)
                self.read_doc(docname)

        def _read_parallel(self, docnames: list[str], nproc: int) -> None:
            chunks = make_chunks(docnames, nproc)

            # create a status_iterator to step progressbar after reading a document
            # (see: ``merge()`` function)
            progress = status_iterator(
                chunks,
                __('reading sources... '),
                'purple',
                len(chunks),
                self.config.verbosity,
            )

            # clear all outdated docs at once
            for docname in docnames:
                self.events.emit('env-purge-doc', self.env, docname)
                self.env.clear_doc(docname)

            def read_process(docs: list[str]) -> bytes:
                self.env._app = self._app
                for docname in docs:
                    self.read_doc(docname, _cache=False)
                # allow pickling self to send it back
                return pickle.dumps(self.env, pickle.HIGHEST_PROTOCOL)

            def merge(docs: list[str], otherenv: bytes) -> None:
                env = pickle.loads(otherenv)
                self.env.merge_info_from(docs, env, self._app)

                next(progress)

            tasks = ParallelTasks(nproc)
            for chunk in chunks:
                tasks.add_task(read_process, chunk, merge)

            # make sure all threads have finished
            tasks.join()
            logger.info('')

        @final
        def read_doc(self, docname: str, *, _cache: bool = True) -> None:
            """Parse a file and add/update inventory entries for the doctree."""
            env = self.env
            env.prepare_settings(docname)

            # Add confdir/docutils.conf to dependencies list if exists
            docutils_conf = self.confdir / 'docutils.conf'
            if docutils_conf.is_file():
                env.note_dependency(docutils_conf)

            filename = env.doc2path(docname)

            # read the source file
            content = filename.read_text(encoding=env.settings['input_encoding'])

            # TODO: move the "source-read" event to here.

            filetype = get_filetype(self.config.source_suffix, filename)
            parser = self._registry.create_source_parser(
                filetype, config=self.config, env=env
            )
            doctree = _parse_str_to_doctree(
                content,
                filename=filename,
                default_role=self.config.default_role,
                default_settings=env.settings,
                env=env,
                events=self.events,
                parser=parser,
                transforms=self._registry.get_transforms(),
            )

            # store time of reading, for outdated files detection
            env.all_docs[docname] = time.time_ns() // 1_000

            # cleanup
            env.current_document = _CurrentDocument()
            env.ref_context.clear()

            self.write_doctree(docname, doctree, _cache=_cache)

        @final
        def write_doctree(
            self,
            docname: str,
            doctree: nodes.document,
            *,
            _cache: bool = True,
        ) -> None:
            """Write the doctree to a file, to be used as a cache by re-builds."""
            # make it pickleable
            doctree.reporter = None  # type: ignore[assignment]
            doctree.transformer = None  # type: ignore[assignment]

            # Create a copy of settings object before modification because it is
            # shared with other documents.
            doctree.settings = doctree.settings.copy()
            doctree.settings.warning_stream = None
            doctree.settings.env = None
            doctree.settings.record_dependencies = DependencyList()

            doctree_filename = self.doctreedir / f'{docname}.doctree'
            doctree_filename.parent.mkdir(parents=True, exist_ok=True)
            with open(doctree_filename, 'wb') as f:
                pickle.dump(doctree, f, pickle.HIGHEST_PROTOCOL)

            # When Sphinx is running in parallel mode, ``write_doctree()`` is invoked
            # in the context of a process worker, and thus it does not make sense to
            # pickle the doctree and send it to the main process
            if _cache:
                self.env._write_doc_doctree_cache[docname] = doctree

        @final
        def write(
            self,
            build_docnames: Iterable[str] | None,
            updated_docnames: Iterable[str],
            method: Literal['all', 'specific', 'update'] = 'update',
        ) -> None:
            """Write builder specific output files."""
            env = self.env

            # Allow any extensions to perform setup for writing
            self.events.emit('write-started', self)

            if build_docnames is None or build_docnames == ['__all__']:
                # build_all
                build_docnames = env.found_docs
            if method == 'update':
                # build updated ones as well
                docnames = set(build_docnames) | set(updated_docnames)
            else:
                docnames = set(build_docnames)
            if docnames:
                logger.debug(__('docnames to write: %s'), ', '.join(sorted(docnames)))
            else:
                logger.debug(__('no docnames to write!'))

            # add all toctree-containing files that may have changed
            docnames |= {
                toc_docname
                for docname in docnames
                for toc_docname in env.files_to_rebuild.get(docname, ())
                if toc_docname in env.found_docs
            }

            # sort to ensure deterministic toctree generation
            env.toctree_includes = dict(sorted(env.toctree_includes.items()))

            with progress_message(__('preparing documents')):
                self.prepare_writing(docnames)

            with progress_message(__('copying assets'), nonl=False):
                self.copy_assets()

            if docnames:
                self.write_documents(docnames)

        def write_documents(self, docnames: Set[str]) -> None:
            """Write all documents in *docnames*.

            This method can be overridden if a builder does not create
            output files for each document.
            """
            sorted_docnames = sorted(docnames)
            if self.parallel_ok:
                # number of subprocesses is parallel-1 because the main process
                # is busy loading doctrees and doing write_doc_serialized()
                self._write_parallel(sorted_docnames, nproc=self._app.parallel - 1)
            else:
                self._write_serial(sorted_docnames)

        def _write_serial(self, docnames: Sequence[str]) -> None:
            with (
                nullcontext()
                if self._app._exception_on_warning
                else logging.pending_warnings()
            ):
                for docname in status_iterator(
                    docnames,
                    __('writing output... '),
                    'darkgreen',
                    len(docnames),
                    self.config.verbosity,
                ):
                    _write_docname(docname, env=self.env, builder=self, tags=self.tags)

        def _write_parallel(self, docnames: Sequence[str], nproc: int) -> None:
            def write_process(docs: list[tuple[str, nodes.document]]) -> None:
                self.phase = BuildPhase.WRITING
                for docname, doctree in docs:
                    self.write_doc(docname, doctree)

            # warm up caches/compile templates using the first document
            firstname, docnames = docnames[0], docnames[1:]
            _write_docname(firstname, env=self.env, builder=self, tags=self.tags)

            tasks = ParallelTasks(nproc)
            chunks = make_chunks(docnames, nproc)

            # create a status_iterator to step progressbar after writing a document
            # (see: ``on_chunk_done()`` function)
            progress = status_iterator(
                chunks,
                __('writing output... '),
                'darkgreen',
                len(chunks),
                self.config.verbosity,
            )

            def on_chunk_done(args: list[tuple[str, nodes.document]], result: None) -> None:
                next(progress)

            self.phase = BuildPhase.RESOLVING
            for chunk in chunks:
                arg = []
                for docname in chunk:
                    doctree = self.env.get_and_resolve_doctree(
                        docname, self, tags=self.tags
                    )
                    self.write_doc_serialized(docname, doctree)
                    arg.append((docname, doctree))
                tasks.add_task(write_process, arg, on_chunk_done)

            # make sure all threads have finished
            tasks.join()
            logger.info('')

        def prepare_writing(self, docnames: Set[str]) -> None:
            """A place where you can add logic before :meth:`write_doc` is run"""
            pass

        def copy_assets(self) -> None:
            """Where assets (images, static files, etc) are copied before writing"""
            pass

        def write_doc(self, docname: str, doctree: nodes.document) -> None:
            """Write the output file for the document

            :param docname: the :term:`docname <document name>`.
            :param doctree: defines the content to be written.

            The output filename must be determined within this method,
            typically by calling :meth:`~.Builder.get_target_uri`
            or :meth:`~.Builder.get_relative_uri`.
            """
            raise NotImplementedError

        def write_doc_serialized(self, docname: str, doctree: nodes.document) -> None:
            """Handle parts of write_doc that must be called in the main process
            if parallel build is active.
            """
            pass

        def finish(self) -> None:
            """Finish the building process.

            The default implementation does nothing.
            """
            pass

        def cleanup(self) -> None:
            """Cleanup any resources.

            The default implementation does nothing.
            """
            pass

        def get_builder_config(self, option: str, default: str) -> Any:
            """Return a builder specific option.

            This method allows customization of common builder settings by
            inserting the name of the current builder in the option key.
            If the key does not exist, use default as builder name.
            """
            # At the moment, only XXX_use_index is looked up this way.
            # Every new builder variant must be registered in Config.config_values.
            try:
                optname = f'{self.name}_{option}'
                return getattr(self.config, optname)
            except AttributeError:
                optname = f'{default}_{option}'
                return getattr(self.config, optname)

    def _write_docname(
        docname: str,
        /,
        *,
        env: BuildEnvironment,
        builder: Builder,
        tags: Tags,
    ) -> None:
        """Write a single document."""
        builder.phase = BuildPhase.RESOLVING
        doctree = env.get_and_resolve_doctree(docname, builder=builder, tags=tags)
        builder.phase = BuildPhase.WRITING
        builder.write_doc_serialized(docname, doctree)
        builder.write_doc(docname, doctree)