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Diffstat (limited to 'Documentation/sphinx/automarkup.py')
| -rw-r--r-- | Documentation/sphinx/automarkup.py | 312 |
1 files changed, 312 insertions, 0 deletions
diff --git a/Documentation/sphinx/automarkup.py b/Documentation/sphinx/automarkup.py new file mode 100644 index 0000000000..06b34740bf --- /dev/null +++ b/Documentation/sphinx/automarkup.py @@ -0,0 +1,312 @@ +# SPDX-License-Identifier: GPL-2.0 +# Copyright 2019 Jonathan Corbet <corbet@lwn.net> +# +# Apply kernel-specific tweaks after the initial document processing +# has been done. +# +from docutils import nodes +import sphinx +from sphinx import addnodes +if sphinx.version_info[0] < 2 or \ + sphinx.version_info[0] == 2 and sphinx.version_info[1] < 1: + from sphinx.environment import NoUri +else: + from sphinx.errors import NoUri +import re +from itertools import chain + +# +# Python 2 lacks re.ASCII... +# +try: + ascii_p3 = re.ASCII +except AttributeError: + ascii_p3 = 0 + +# +# Regex nastiness. Of course. +# Try to identify "function()" that's not already marked up some +# other way. Sphinx doesn't like a lot of stuff right after a +# :c:func: block (i.e. ":c:func:`mmap()`s" flakes out), so the last +# bit tries to restrict matches to things that won't create trouble. +# +RE_function = re.compile(r'\b(([a-zA-Z_]\w+)\(\))', flags=ascii_p3) + +# +# Sphinx 2 uses the same :c:type role for struct, union, enum and typedef +# +RE_generic_type = re.compile(r'\b(struct|union|enum|typedef)\s+([a-zA-Z_]\w+)', + flags=ascii_p3) + +# +# Sphinx 3 uses a different C role for each one of struct, union, enum and +# typedef +# +RE_struct = re.compile(r'\b(struct)\s+([a-zA-Z_]\w+)', flags=ascii_p3) +RE_union = re.compile(r'\b(union)\s+([a-zA-Z_]\w+)', flags=ascii_p3) +RE_enum = re.compile(r'\b(enum)\s+([a-zA-Z_]\w+)', flags=ascii_p3) +RE_typedef = re.compile(r'\b(typedef)\s+([a-zA-Z_]\w+)', flags=ascii_p3) + +# +# Detects a reference to a documentation page of the form Documentation/... with +# an optional extension +# +RE_doc = re.compile(r'(\bDocumentation/)?((\.\./)*[\w\-/]+)\.(rst|txt)') + +RE_namespace = re.compile(r'^\s*..\s*c:namespace::\s*(\S+)\s*$') + +# +# Reserved C words that we should skip when cross-referencing +# +Skipnames = [ 'for', 'if', 'register', 'sizeof', 'struct', 'unsigned' ] + + +# +# Many places in the docs refer to common system calls. It is +# pointless to try to cross-reference them and, as has been known +# to happen, somebody defining a function by these names can lead +# to the creation of incorrect and confusing cross references. So +# just don't even try with these names. +# +Skipfuncs = [ 'open', 'close', 'read', 'write', 'fcntl', 'mmap', + 'select', 'poll', 'fork', 'execve', 'clone', 'ioctl', + 'socket' ] + +c_namespace = '' + +def markup_refs(docname, app, node): + t = node.astext() + done = 0 + repl = [ ] + # + # Associate each regex with the function that will markup its matches + # + markup_func_sphinx2 = {RE_doc: markup_doc_ref, + RE_function: markup_c_ref, + RE_generic_type: markup_c_ref} + + markup_func_sphinx3 = {RE_doc: markup_doc_ref, + RE_function: markup_func_ref_sphinx3, + RE_struct: markup_c_ref, + RE_union: markup_c_ref, + RE_enum: markup_c_ref, + RE_typedef: markup_c_ref} + + if sphinx.version_info[0] >= 3: + markup_func = markup_func_sphinx3 + else: + markup_func = markup_func_sphinx2 + + match_iterators = [regex.finditer(t) for regex in markup_func] + # + # Sort all references by the starting position in text + # + sorted_matches = sorted(chain(*match_iterators), key=lambda m: m.start()) + for m in sorted_matches: + # + # Include any text prior to match as a normal text node. + # + if m.start() > done: + repl.append(nodes.Text(t[done:m.start()])) + + # + # Call the function associated with the regex that matched this text and + # append its return to the text + # + repl.append(markup_func[m.re](docname, app, m)) + + done = m.end() + if done < len(t): + repl.append(nodes.Text(t[done:])) + return repl + +# +# Keep track of cross-reference lookups that failed so we don't have to +# do them again. +# +failed_lookups = { } +def failure_seen(target): + return (target) in failed_lookups +def note_failure(target): + failed_lookups[target] = True + +# +# In sphinx3 we can cross-reference to C macro and function, each one with its +# own C role, but both match the same regex, so we try both. +# +def markup_func_ref_sphinx3(docname, app, match): + cdom = app.env.domains['c'] + # + # Go through the dance of getting an xref out of the C domain + # + base_target = match.group(2) + target_text = nodes.Text(match.group(0)) + xref = None + possible_targets = [base_target] + # Check if this document has a namespace, and if so, try + # cross-referencing inside it first. + if c_namespace: + possible_targets.insert(0, c_namespace + "." + base_target) + + if base_target not in Skipnames: + for target in possible_targets: + if (target not in Skipfuncs) and not failure_seen(target): + lit_text = nodes.literal(classes=['xref', 'c', 'c-func']) + lit_text += target_text + pxref = addnodes.pending_xref('', refdomain = 'c', + reftype = 'function', + reftarget = target, + modname = None, + classname = None) + # + # XXX The Latex builder will throw NoUri exceptions here, + # work around that by ignoring them. + # + try: + xref = cdom.resolve_xref(app.env, docname, app.builder, + 'function', target, pxref, + lit_text) + except NoUri: + xref = None + + if xref: + return xref + note_failure(target) + + return target_text + +def markup_c_ref(docname, app, match): + class_str = {# Sphinx 2 only + RE_function: 'c-func', + RE_generic_type: 'c-type', + # Sphinx 3+ only + RE_struct: 'c-struct', + RE_union: 'c-union', + RE_enum: 'c-enum', + RE_typedef: 'c-type', + } + reftype_str = {# Sphinx 2 only + RE_function: 'function', + RE_generic_type: 'type', + # Sphinx 3+ only + RE_struct: 'struct', + RE_union: 'union', + RE_enum: 'enum', + RE_typedef: 'type', + } + + cdom = app.env.domains['c'] + # + # Go through the dance of getting an xref out of the C domain + # + base_target = match.group(2) + target_text = nodes.Text(match.group(0)) + xref = None + possible_targets = [base_target] + # Check if this document has a namespace, and if so, try + # cross-referencing inside it first. + if c_namespace: + possible_targets.insert(0, c_namespace + "." + base_target) + + if base_target not in Skipnames: + for target in possible_targets: + if not (match.re == RE_function and target in Skipfuncs): + lit_text = nodes.literal(classes=['xref', 'c', class_str[match.re]]) + lit_text += target_text + pxref = addnodes.pending_xref('', refdomain = 'c', + reftype = reftype_str[match.re], + reftarget = target, modname = None, + classname = None) + # + # XXX The Latex builder will throw NoUri exceptions here, + # work around that by ignoring them. + # + try: + xref = cdom.resolve_xref(app.env, docname, app.builder, + reftype_str[match.re], target, pxref, + lit_text) + except NoUri: + xref = None + + if xref: + return xref + + return target_text + +# +# Try to replace a documentation reference of the form Documentation/... with a +# cross reference to that page +# +def markup_doc_ref(docname, app, match): + stddom = app.env.domains['std'] + # + # Go through the dance of getting an xref out of the std domain + # + absolute = match.group(1) + target = match.group(2) + if absolute: + target = "/" + target + xref = None + pxref = addnodes.pending_xref('', refdomain = 'std', reftype = 'doc', + reftarget = target, modname = None, + classname = None, refexplicit = False) + # + # XXX The Latex builder will throw NoUri exceptions here, + # work around that by ignoring them. + # + try: + xref = stddom.resolve_xref(app.env, docname, app.builder, 'doc', + target, pxref, None) + except NoUri: + xref = None + # + # Return the xref if we got it; otherwise just return the plain text. + # + if xref: + return xref + else: + return nodes.Text(match.group(0)) + +def get_c_namespace(app, docname): + source = app.env.doc2path(docname) + with open(source) as f: + for l in f: + match = RE_namespace.search(l) + if match: + return match.group(1) + return '' + +def auto_markup(app, doctree, name): + global c_namespace + c_namespace = get_c_namespace(app, name) + def text_but_not_a_reference(node): + # The nodes.literal test catches ``literal text``, its purpose is to + # avoid adding cross-references to functions that have been explicitly + # marked with cc:func:. + if not isinstance(node, nodes.Text) or isinstance(node.parent, nodes.literal): + return False + + child_of_reference = False + parent = node.parent + while parent: + if isinstance(parent, nodes.Referential): + child_of_reference = True + break + parent = parent.parent + return not child_of_reference + + # + # This loop could eventually be improved on. Someday maybe we + # want a proper tree traversal with a lot of awareness of which + # kinds of nodes to prune. But this works well for now. + # + for para in doctree.traverse(nodes.paragraph): + for node in para.traverse(condition=text_but_not_a_reference): + node.parent.replace(node, markup_refs(name, app, node)) + +def setup(app): + app.connect('doctree-resolved', auto_markup) + return { + 'parallel_read_safe': True, + 'parallel_write_safe': True, + } |