| # 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 | |
| from sphinx.errors import NoUri | |
| import re | |
| from itertools import chain | |
| from kernel_abi import get_kernel_abi | |
| # | |
| # 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=re.ASCII) | |
| # | |
| # 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=re.ASCII) | |
| RE_union = re.compile(r'\b(union)\s+([a-zA-Z_]\w+)', flags=re.ASCII) | |
| RE_enum = re.compile(r'\b(enum)\s+([a-zA-Z_]\w+)', flags=re.ASCII) | |
| RE_typedef = re.compile(r'\b(typedef)\s+([a-zA-Z_]\w+)', flags=re.ASCII) | |
| # | |
| # 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_abi_file = re.compile(r'(\bDocumentation/ABI/[\w\-/]+)') | |
| RE_abi_symbol = re.compile(r'(\b/(sys|config|proc)/[\w\-/]+)') | |
| 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' ] | |
| # | |
| # Common English words that should not be recognized as C identifiers | |
| # when following struct/union/enum/typedef keywords. | |
| # Example: "a simple struct that" in workqueue.rst should not be marked as code. | |
| # | |
| Skipidentifiers = [ 'that', 'which', 'where', 'whose' ] | |
| # | |
| # 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 = '' | |
| # | |
| # Detect references to commits. | |
| # | |
| RE_git = re.compile(r'commit\s+(?P<rev>[0-9a-f]{12,40})(?:\s+\(".*?"\))?', | |
| flags=re.IGNORECASE | re.DOTALL) | |
| 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 = {RE_doc: markup_doc_ref, | |
| RE_abi_file: markup_abi_file_ref, | |
| RE_abi_symbol: markup_abi_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, | |
| RE_git: markup_git} | |
| 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): | |
| base_target = match.group(2) | |
| target_text = nodes.Text(match.group(0)) | |
| 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 | |
| xref = add_and_resolve_xref(app, docname, 'c', 'function', | |
| target, contnode=lit_text) | |
| if xref: | |
| return xref | |
| note_failure(target) | |
| return target_text | |
| def markup_c_ref(docname, app, match): | |
| class_str = {RE_struct: 'c-struct', | |
| RE_union: 'c-union', | |
| RE_enum: 'c-enum', | |
| RE_typedef: 'c-type', | |
| } | |
| reftype_str = {RE_struct: 'struct', | |
| RE_union: 'union', | |
| RE_enum: 'enum', | |
| RE_typedef: 'type', | |
| } | |
| base_target = match.group(2) | |
| target_text = nodes.Text(match.group(0)) | |
| 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) | |
| # Skip common English words that match identifier pattern but are not C code. | |
| if base_target in Skipidentifiers: | |
| return target_text | |
| 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 | |
| xref = add_and_resolve_xref(app, docname, 'c', | |
| reftype_str[match.re], target, | |
| contnode=lit_text) | |
| 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): | |
| absolute = match.group(1) | |
| target = match.group(2) | |
| if absolute: | |
| target = "/" + target | |
| xref = add_and_resolve_xref(app, docname, 'std', 'doc', target) | |
| if xref: | |
| return xref | |
| else: | |
| return nodes.Text(match.group(0)) | |
| # | |
| # Try to replace a documentation reference for ABI symbols and files | |
| # with a cross reference to that page | |
| # | |
| def markup_abi_ref(docname, app, match, warning=False): | |
| kernel_abi = get_kernel_abi() | |
| fname = match.group(1) | |
| target = kernel_abi.xref(fname) | |
| # Kernel ABI doesn't describe such file or symbol | |
| if not target: | |
| if warning: | |
| kernel_abi.log.warning("%s not found", fname) | |
| return nodes.Text(match.group(0)) | |
| xref = add_and_resolve_xref(app, docname, 'std', 'ref', target) | |
| if xref: | |
| return xref | |
| else: | |
| return nodes.Text(match.group(0)) | |
| def add_and_resolve_xref(app, docname, domain, reftype, target, contnode=None): | |
| # | |
| # Go through the dance of getting an xref out of the corresponding domain | |
| # | |
| dom_obj = app.env.domains[domain] | |
| pxref = addnodes.pending_xref('', refdomain = domain, reftype = reftype, | |
| 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 = dom_obj.resolve_xref(app.env, docname, app.builder, reftype, | |
| target, pxref, contnode) | |
| except NoUri: | |
| xref = None | |
| if xref: | |
| return xref | |
| # | |
| # We didn't find the xref; if a container node was supplied, | |
| # mark it as a broken xref | |
| # | |
| if contnode: | |
| contnode['classes'].append("broken_xref") | |
| return contnode | |
| # | |
| # Variant of markup_abi_ref() that warns when a reference is not found | |
| # | |
| def markup_abi_file_ref(docname, app, match): | |
| return markup_abi_ref(docname, app, match, warning=True) | |
| 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 markup_git(docname, app, match): | |
| # While we could probably assume that we are running in a git | |
| # repository, we can't know for sure, so let's just mechanically | |
| # turn them into git.kernel.org links without checking their | |
| # validity. (Maybe we can do something in the future to warn about | |
| # these references if this is explicitly requested.) | |
| text = match.group(0) | |
| rev = match.group('rev') | |
| return nodes.reference('', nodes.Text(text), | |
| refuri=f'https://git.kernel.org/torvalds/c/{rev}') | |
| 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, | |
| } |