Generate documentation with Sphinx

1 files changed, 674 insertions, 0 deletions

diff --git a/scripts/dox_to_sphinx.py b/scripts/dox_to_sphinx.py
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+++ b/scripts/dox_to_sphinx.py
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+#!/usr/bin/env python3
+
+# Copyright 2020 David Robillard <d@drobilla.net>
+#
+# Permission to use, copy, modify, and/or distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+"""
+Write Sphinx markup from Doxygen XML.
+
+Takes a path to a directory of XML generated by Doxygen, and emits a directory
+with a reStructuredText file for every documented symbol.
+"""
+
+import argparse
+import os
+import sys
+import textwrap
+import xml.etree.ElementTree
+
+__author__ = "David Robillard"
+__date__ = "2020-11-18"
+__email__ = "d@drobilla.net"
+__license__ = "ISC"
+__version__ = __date__.replace("-", ".")
+
+
+def load_index(index_path):
+    """
+    Load the index from XML.
+
+    :returns: A dictionary from ID to skeleton records with basic information
+    for every documented entity.  Some records have an ``xml_filename`` key
+    with the filename of a definition file.  These files will be loaded later
+    to flesh out the records in the index.
+    """
+
+    root = xml.etree.ElementTree.parse(index_path).getroot()
+    index = {}
+
+    for compound in root:
+        compound_id = compound.get("refid")
+        compound_kind = compound.get("kind")
+        compound_name = compound.find("name").text
+        if compound_kind in ["dir", "file", "page"]:
+            continue
+
+        # Add record for compound (compounds appear only once in the index)
+        assert compound_id not in index
+        index[compound_id] = {
+            "kind": compound_kind,
+            "name": compound_name,
+            "xml_filename": compound_id + ".xml",
+            "children": [],
+        }
+
+        name_prefix = (
+            ("%s::" % compound_name) if compound_kind == "namespace" else ""
+        )
+
+        for child in compound.findall("member"):
+            if child.get("refid") in index:
+                assert compound_kind == "group"
+                continue
+
+            # Everything has a kind and a name
+            child_record = {
+                "kind": child.get("kind"),
+                "name": name_prefix + child.find("name").text,
+            }
+
+            if child.get("kind") == "enum":
+                # Enums are not compounds, but we want to resolve the parent of
+                # their values so they are not written as top level documents
+                child_record["children"] = []
+
+            if child.get("kind") == "enumvalue":
+                # Remove namespace prefix
+                child_record["name"] = child.find("name").text
+
+            index[child.get("refid")] = child_record
+
+    return index
+
+
+def resolve_index(index, root):
+    """
+    Walk a definition document and extend the index for linking.
+
+    This does two things: sets the "parent" and "children" fields of all
+    applicable records, and sets the "strong" field of enums so that the
+    correct Sphinx role can be used when referring to them.
+    """
+
+    def add_child(index, parent_id, child_id):
+        parent = index[parent_id]
+        child = index[child_id]
+
+        if child["kind"] == "enumvalue":
+            assert parent["kind"] == "enum"
+            assert "parent" not in child or child["parent"] == parent_id
+            child["parent"] = parent_id
+
+        else:
+            if parent["kind"] in ["class", "struct", "union"]:
+                assert "parent" not in child or child["parent"] == parent_id
+                child["parent"] = parent_id
+
+        if child_id not in parent["children"]:
+            parent["children"] += [child_id]
+
+    compound = root.find("compounddef")
+    compound_kind = compound.get("kind")
+
+    if compound_kind == "group":
+        for subgroup in compound.findall("innergroup"):
+            add_child(index, compound.get("id"), subgroup.get("refid"))
+
+        for klass in compound.findall("innerclass"):
+            add_child(index, compound.get("id"), klass.get("refid"))
+
+    for section in compound.findall("sectiondef"):
+        if section.get("kind").startswith("private"):
+            for member in section.findall("memberdef"):
+                if member.get("id") in index:
+                    del index[member.get("id")]
+        else:
+            for member in section.findall("memberdef"):
+                member_id = member.get("id")
+                add_child(index, compound.get("id"), member_id)
+
+                if member.get("kind") == "enum":
+                    index[member_id]["strong"] = member.get("strong") == "yes"
+                    for value in member.findall("enumvalue"):
+                        add_child(index, member_id, value.get("id"))
+
+
+def sphinx_role(record, lang):
+    """
+    Return the Sphinx role used for a record.
+
+    This is used for the description directive like ".. c:function::", and
+    links like ":c:func:`foo`.
+    """
+
+    kind = record["kind"]
+
+    if kind in ["class", "function", "namespace", "struct", "union"]:
+        return lang + ":" + kind
+
+    if kind == "define":
+        return "c:macro"
+
+    if kind == "enum":
+        return lang + (":enum-class" if record["strong"] else ":enum")
+
+    if kind == "typedef":
+        return lang + ":type"
+
+    if kind == "enumvalue":
+        return lang + ":enumerator"
+
+    if kind == "variable":
+        return lang + (":member" if "parent" in record else ":var")
+
+    raise RuntimeError("No known role for kind '%s'" % kind)
+
+
+def child_identifier(lang, parent_name, child_name):
+    """
+    Return the identifier for an enum value or struct member.
+
+    Sphinx, for some reason, uses a different syntax for this in C and C++.
+    """
+
+    separator = "::" if lang == "cpp" else "."
+
+    return "%s%s%s" % (parent_name, separator, child_name)
+
+
+def link_markup(index, lang, refid):
+    """Return a Sphinx link for a Doxygen reference."""
+
+    record = index[refid]
+    kind, name = record["kind"], record["name"]
+    role = sphinx_role(record, lang)
+
+    if kind in ["class", "enum", "struct", "typedef", "union"]:
+        return ":%s:`%s`" % (role, name)
+
+    if kind == "function":
+        return ":%s:func:`%s`" % (lang, name)
+
+    if kind == "enumvalue":
+        parent_name = index[record["parent"]]["name"]
+        return ":%s:`%s`" % (role, child_identifier(lang, parent_name, name))
+
+    if kind == "variable":
+        if "parent" not in record:
+            return ":%s:var:`%s`" % (lang, name)
+
+        parent_name = index[record["parent"]]["name"]
+        return ":%s:`%s`" % (role, child_identifier(lang, parent_name, name))
+
+    raise RuntimeError("Unknown link target kind: %s" % kind)
+
+
+def indent(markup, depth):
+    """
+    Indent markup to a depth level.
+
+    Like textwrap.indent() but takes an integer and works in reST indentation
+    levels for clarity."
+    """
+
+    return textwrap.indent(markup, "   " * depth)
+
+
+def heading(text, level):
+    """
+    Return a ReST heading at a given level.
+
+    Follows the style in the Python documentation guide, see
+    <https://devguide.python.org/documenting/#sections>.
+    """
+
+    assert 1 <= level <= 6
+
+    chars = ("#", "*", "=", "-", "^", '"')
+    line = chars[level] * len(text)
+
+    return "%s\n%s\n%s\n\n" % (line if level < 3 else "", text, line)
+
+
+def dox_to_rst(index, lang, node):
+    """
+    Convert documentation commands (docCmdGroup) to Sphinx markup.
+
+    This is used to convert the content of descriptions in the documentation.
+    It recursively parses all children tags and raises a RuntimeError if any
+    unknown tag is encountered.
+    """
+
+    def field_value(markup):
+        """Return a value for a field as a single line or indented block."""
+        if "\n" in markup.strip():
+            return "\n" + indent(markup, 1)
+
+        return " " + markup.strip()
+
+    if node.tag == "computeroutput":
+        # assert len(node) == 0 FIXME
+        return "``%s``" % node.text
+
+    if node.tag == "itemizedlist":
+        markup = ""
+        for item in node.findall("listitem"):
+            assert len(item) == 1
+            markup += "\n- %s" % dox_to_rst(index, lang, item[0])
+
+        return markup
+
+    if node.tag == "para":
+        markup = node.text if node.text is not None else ""
+        for child in node:
+            markup += dox_to_rst(index, lang, child)
+            markup += child.tail if child.tail is not None else ""
+
+        return markup.strip() + "\n\n"
+
+    if node.tag == "parameterlist":
+        markup = ""
+        for item in node.findall("parameteritem"):
+            name = item.find("parameternamelist/parametername")
+            description = item.find("parameterdescription")
+            assert len(description) == 1
+            markup += "\n\n:param %s:%s" % (
+                name.text,
+                field_value(dox_to_rst(index, lang, description[0])),
+            )
+
+        return markup + "\n"
+
+    if node.tag == "programlisting":
+        return "\n.. code-block:: %s\n\n%s" % (
+            lang,
+            indent(plain_text(node), 1),
+        )
+
+    if node.tag == "ref":
+        refid = node.get("refid")
+        if refid not in index:
+            sys.stderr.write("warning: Unresolved link: %s\n" % refid)
+            return node.text
+
+        assert len(node) == 0
+        assert len(link_markup(index, lang, refid)) > 0
+        return link_markup(index, lang, refid)
+
+    if node.tag == "simplesect":
+        assert len(node) == 1
+
+        if node.get("kind") == "return":
+            return "\n:returns:" + field_value(
+                dox_to_rst(index, lang, node[0])
+            )
+
+        if node.get("kind") == "see":
+            return dox_to_rst(index, lang, node[0])
+
+        raise RuntimeError("Unknown simplesect kind: %s" % node.get("kind"))
+
+    if node.tag == "ulink":
+        return "`%s <%s>`_" % (node.text, node.get("url"))
+
+    raise RuntimeError("Unknown documentation command: %s" % node.tag)
+
+
+def description_markup(index, lang, node):
+    """Return the markup for a brief or detailed description."""
+
+    assert node.tag == "briefdescription" or node.tag == "detaileddescription"
+    assert not (node.tag == "briefdescription" and len(node) > 1)
+    assert len(node.text.strip()) == 0
+
+    return "".join([dox_to_rst(index, lang, child) for child in node])
+
+
+def set_descriptions(index, lang, definition, record):
+    """Set a record's brief/detailed descriptions from the XML definition."""
+
+    for tag in ["briefdescription", "detaileddescription"]:
+        node = definition.find(tag)
+        if node is not None:
+            record[tag] = description_markup(index, lang, node)
+
+
+def set_template_params(node, record):
+    """Set a record's template_params from the XML definition."""
+
+    template_param_list = node.find("templateparamlist")
+    if template_param_list is not None:
+        params = []
+        for param in template_param_list.findall("param"):
+            if param.find("declname") is not None:
+                # Value parameter
+                type_text = plain_text(param.find("type"))
+                name_text = plain_text(param.find("declname"))
+
+                params += ["%s %s" % (type_text, name_text)]
+            else:
+                # Type parameter
+                params += ["%s" % (plain_text(param.find("type")))]
+
+        record["template_params"] = "%s" % ", ".join(params)
+
+
+def plain_text(node):
+    """
+    Return the plain text of a node with all tags ignored.
+
+    This is needed where Doxygen may include refs but Sphinx needs plain text
+    because it parses things itself to generate links.
+    """
+
+    if node.tag == "sp":
+        markup = " "
+    elif node.text is not None:
+        markup = node.text
+    else:
+        markup = ""
+
+    for child in node:
+        markup += plain_text(child)
+        markup += child.tail if child.tail is not None else ""
+
+    return markup
+
+
+def local_name(name):
+    """Return a name with all namespace prefixes stripped."""
+
+    return name[name.rindex("::") + 2 :] if "::" in name else name
+
+
+def read_definition_doc(index, lang, root):
+    """Walk a definition document and update described records in the index."""
+
+    # Set descriptions for the compound itself
+    compound = root.find("compounddef")
+    compound_record = index[compound.get("id")]
+    set_descriptions(index, lang, compound, compound_record)
+    set_template_params(compound, compound_record)
+
+    if compound.find("title") is not None:
+        compound_record["title"] = compound.find("title").text.strip()
+
+    # Set documentation for all children
+    for section in compound.findall("sectiondef"):
+        if section.get("kind").startswith("private"):
+            continue
+
+        for member in section.findall("memberdef"):
+            kind = member.get("kind")
+            record = index[member.get("id")]
+            set_descriptions(index, lang, member, record)
+            set_template_params(member, record)
+
+            if compound.get("kind") in ["class", "struct", "union"]:
+                assert kind in ["function", "typedef", "variable"]
+                record["type"] = plain_text(member.find("type"))
+
+            if kind == "enum":
+                for value in member.findall("enumvalue"):
+                    set_descriptions(
+                        index, lang, value, index[value.get("id")]
+                    )
+
+            elif kind == "function":
+                record["prototype"] = "%s %s%s" % (
+                    plain_text(member.find("type")),
+                    member.find("name").text,
+                    member.find("argsstring").text,
+                )
+
+            elif kind == "typedef":
+                name = local_name(record["name"])
+                args_text = member.find("argsstring").text
+                target_text = plain_text(member.find("type"))
+                if args_text is not None:  # Function pointer
+                    assert target_text[-2:] == "(*" and args_text[0] == ")"
+                    record["type"] = target_text + args_text
+                    record["definition"] = target_text + name + args_text
+                else:  # Normal named typedef
+                    assert target_text is not None
+                    record["type"] = target_text
+                    if member.find("definition").text.startswith("using"):
+                        record["definition"] = "%s = %s" % (
+                            name,
+                            target_text,
+                        )
+                    else:
+                        record["definition"] = "%s %s" % (
+                            target_text,
+                            name,
+                        )
+
+            elif kind == "variable":
+                record["definition"] = member.find("definition").text
+
+
+def declaration_string(record):
+    """
+    Return the string that describes a declaration.
+
+    This is what follows the directive, and is in C/C++ syntax, except without
+    keywords like "typedef" and "using" as expected by Sphinx.  For example,
+    "struct ThingImpl Thing" or "void run(int value)".
+    """
+
+    kind = record["kind"]
+    result = ""
+
+    if "template_params" in record:
+        result = "template <%s> " % record["template_params"]
+
+    if kind == "function":
+        result += record["prototype"]
+    elif kind == "typedef":
+        result += record["definition"]
+    elif kind == "variable":
+        if "parent" in record:
+            result += "%s %s" % (record["type"], local_name(record["name"]))
+        else:
+            result += record["definition"]
+    elif "type" in record:
+        result += "%s %s" % (record["type"], local_name(record["name"]))
+    else:
+        result += local_name(record["name"])
+
+    return result
+
+
+def document_markup(index, lang, record):
+    """Return the complete document that describes some documented entity."""
+
+    kind = record["kind"]
+    role = sphinx_role(record, lang)
+    name = record["name"]
+    markup = ""
+
+    if name != local_name(name):
+        markup += ".. cpp:namespace:: %s\n\n" % name[0 : name.rindex("::")]
+
+    # Write top-level directive
+    markup += ".. %s:: %s\n" % (role, declaration_string(record))
+
+    # Write main description blurb
+    markup += "\n"
+    markup += indent(record["briefdescription"], 1)
+    markup += indent(record["detaileddescription"], 1)
+
+    assert (
+        kind in ["class", "enum", "namespace", "struct", "union"]
+        or "children" not in record
+    )
+
+    # Sphinx C++ namespaces work by setting a scope, they have no content
+    child_indent = 0 if kind == "namespace" else 1
+
+    # Write inline children if applicable
+    markup += "\n"
+    for child_id in record.get("children", []):
+        child_record = index[child_id]
+        child_role = sphinx_role(child_record, lang)
+
+        child_header = ".. %s:: %s\n\n" % (
+            child_role,
+            declaration_string(child_record),
+        )
+
+        markup += "\n"
+        markup += indent(child_header, child_indent)
+        markup += indent(child_record["briefdescription"], child_indent + 1)
+        markup += indent(child_record["detaileddescription"], child_indent + 1)
+        markup += "\n"
+
+    return markup
+
+
+def symbol_filename(name):
+    """Adapt the name of a symbol to be suitable for use as a filename."""
+
+    return name.replace("::", "__")
+
+
+def emit_symbols(index, lang, symbol_dir, force):
+    """Write a description file for every symbol documented in the index."""
+
+    for record in index.values():
+        if (
+            record["kind"] in ["group", "namespace"]
+            or "parent" in record
+            and index[record["parent"]]["kind"] != "group"
+        ):
+            continue
+
+        name = record["name"]
+        filename = os.path.join(symbol_dir, symbol_filename("%s.rst" % name))
+        if not force and os.path.exists(filename):
+            raise FileExistsError("File already exists: '%s'" % filename)
+
+        with open(filename, "w") as rst:
+            rst.write(heading(local_name(name), 3))
+            rst.write(document_markup(index, lang, record))
+
+
+def emit_groups(index, output_dir, symbol_dir_name, force):
+    """Write a description file for every group documented in the index."""
+
+    for record in index.values():
+        if record["kind"] != "group":
+            continue
+
+        name = record["name"]
+        filename = os.path.join(output_dir, "%s.rst" % name)
+        if not force and os.path.exists(filename):
+            raise FileExistsError("File already exists: '%s'" % filename)
+
+        with open(filename, "w") as rst:
+            rst.write(heading(record["title"], 2))
+
+            # Get all child group and symbol names
+            group_names = []
+            symbol_names = []
+            for child_id in record["children"]:
+                child = index[child_id]
+                if child["kind"] == "group":
+                    group_names += [child["name"]]
+                else:
+                    symbol_names += [child["name"]]
+
+            # Emit description (document body)
+            rst.write(record["briefdescription"] + "\n\n")
+            rst.write(record["detaileddescription"] + "\n\n")
+
+            # Emit TOC
+            rst.write(".. toctree::\n")
+
+            # Emit groups at the top of the TOC
+            for group_name in group_names:
+                rst.write("\n" + indent(group_name, 1))
+
+            # Emit symbols in sorted order
+            for symbol_name in sorted(symbol_names):
+                path = "/".join(
+                    [symbol_dir_name, symbol_filename(symbol_name)]
+                )
+                rst.write("\n" + indent(path, 1))
+
+            rst.write("\n")
+
+
+def run(index_xml_path, output_dir, symbol_dir_name, language, force):
+    """Write a directory of Sphinx files from a Doxygen XML directory."""
+
+    # Build skeleton index from index.xml
+    xml_dir = os.path.dirname(index_xml_path)
+    index = load_index(index_xml_path)
+
+    # Load all definition documents
+    definition_docs = []
+    for record in index.values():
+        if "xml_filename" in record:
+            xml_path = os.path.join(xml_dir, record["xml_filename"])
+            definition_docs += [xml.etree.ElementTree.parse(xml_path)]
+
+    # Do an initial pass of the definition documents to resolve the index
+    for root in definition_docs:
+        resolve_index(index, root)
+
+    # Finally read the documentation from definition documents
+    for root in definition_docs:
+        read_definition_doc(index, language, root)
+
+    # Emit output files
+    symbol_dir = os.path.join(output_dir, symbol_dir_name)
+    os.makedirs(symbol_dir, exist_ok=True)
+    emit_symbols(index, language, symbol_dir, force)
+    emit_groups(index, output_dir, symbol_dir_name, force)
+
+
+if __name__ == "__main__":
+    ap = argparse.ArgumentParser(
+        usage="%(prog)s [OPTION]... XML_DIR OUTPUT_DIR",
+        description=__doc__,
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+    )
+
+    ap.add_argument(
+        "-f",
+        "--force",
+        action="store_true",
+        help="overwrite files",
+    )
+
+    ap.add_argument(
+        "-l",
+        "--language",
+        default="c",
+        choices=["c", "cpp"],
+        help="language domain for output",
+    )
+
+    ap.add_argument(
+        "-s",
+        "--symbol-dir-name",
+        default="symbols",
+        help="name for subdirectory of symbol documentation files",
+    )
+
+    ap.add_argument("index_xml_path", help="path index.xml from Doxygen")
+    ap.add_argument("output_dir", help="output directory")
+
+    run(**vars(ap.parse_args(sys.argv[1:])))