Adding upstream version 0.18.1.upstream/0.18.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 440 insertions, 0 deletions

diff --git a/myst_parser/parsers/parse_html.py b/myst_parser/parsers/parse_html.py
new file mode 100644
index 0000000..7539e42
--- /dev/null
+++ b/myst_parser/parsers/parse_html.py
@@ -0,0 +1,440 @@
+"""A simple but complete HTML to Abstract Syntax Tree (AST) parser.
+
+The AST can also reproduce the HTML text.
+
+Example::
+
+    >> text = '<div class="note"><p>text</p></div>'
+    >> ast = tokenize_html(text)
+    >> list(ast.walk(include_self=True))
+    [Root(''), Tag('div', {'class': 'note'}), Tag('p'), Data('text')]
+    >> str(ast)
+    '<div class="note"><p>text</p></div>'
+    >> str(ast[0][0])
+    '<p>text</p>'
+
+Note: optional tags are not accounted for
+(see https://html.spec.whatwg.org/multipage/syntax.html#optional-tags)
+
+"""
+from __future__ import annotations
+
+import inspect
+import itertools
+from collections import abc, deque
+from html.parser import HTMLParser
+from typing import Any, Callable, Iterable, Iterator
+
+
+class Attribute(dict):
+    """This class holds the tags's attributes."""
+
+    def __getitem__(self, key: str) -> str:
+        """If self doesn't have the key it returns ''."""
+        return self.get(key, "")
+
+    @property
+    def classes(self) -> list[str]:
+        """Return 'class' attribute as list."""
+        return self["class"].split()
+
+    def __str__(self) -> str:
+        """Return a htmlized representation for attributes."""
+        return " ".join(f'{key}="{value}"' for key, value in self.items())
+
+
+class Element(abc.MutableSequence):
+    """An Element of the xml/html document.
+
+    All xml/html entities inherit from this class.
+    """
+
+    def __init__(self, name: str = "", attr: dict | None = None) -> None:
+        """Initialise the element."""
+        self.name = name
+        self.attrs: Attribute = Attribute(attr or {})
+        self._parent: Element | None = None
+        self._children: list[Element] = []
+
+    @property
+    def parent(self) -> Element | None:
+        """Return parent."""
+        return self._parent
+
+    @property
+    def children(self) -> list[Element]:
+        """Return copy of children."""
+        return self._children[:]
+
+    def reset_children(self, children: list[Element], deepcopy: bool = False):
+        new_children = []
+        for i, item in enumerate(children):
+            assert isinstance(item, Element)
+            if deepcopy:
+                item = item.deepcopy()
+            if item._parent is None:
+                item._parent = self
+            elif item._parent != self:
+                raise AssertionError(f"different parent already set for item {i}")
+            new_children.append(item)
+        self._children = new_children
+
+    def __getitem__(self, index: int) -> Element:  # type: ignore[override]
+        return self._children[index]
+
+    def __setitem__(self, index: int, item: Element):  # type: ignore[override]
+        assert isinstance(item, Element)
+        if item._parent is not None and item._parent != self:
+            raise AssertionError(f"different parent already set for: {item!r}")
+        item._parent = self
+        return self._children.__setitem__(index, item)
+
+    def __delitem__(self, index: int):  # type: ignore[override]
+        return self._children.__delitem__(index)
+
+    def __len__(self) -> int:
+        return self._children.__len__()
+
+    def __iter__(self) -> Iterator[Element]:
+        yield from self._children
+
+    def insert(self, index: int, item: Element):
+        assert isinstance(item, Element)
+        if item._parent is not None and item._parent != self:
+            raise AssertionError(f"different parent already set for: {item!r}")
+        item._parent = self
+        return self._children.insert(index, item)
+
+    def deepcopy(self) -> Element:
+        """Recursively copy and remove parent."""
+        _copy = self.__class__(self.name, self.attrs)
+        for child in self:
+            _copy_child = child.deepcopy()
+            _copy.append(_copy_child)
+        return _copy
+
+    def __repr__(self) -> str:
+        text = f"{self.__class__.__name__}({self.name!r}"
+        if self.attrs:
+            text += f", {self.attrs!r}"
+        text += ")"
+        return text
+
+    def render(
+        self,
+        tag_overrides: dict[str, Callable[[Element, dict], str]] | None = None,
+        **kwargs,
+    ) -> str:
+        """Returns a HTML string representation of the element.
+
+        :param tag_overrides: Provide a dictionary of render function
+            for specific tag names, to override the normal render format
+
+        """
+        raise NotImplementedError
+
+    def __str__(self) -> str:
+        return self.render()
+
+    def __eq__(self, item: Any) -> bool:
+        return item is self
+
+    def walk(self, include_self: bool = False) -> Iterator[Element]:
+        """Walk through the xml/html AST."""
+        if include_self:
+            yield self
+        for child in self:
+            yield child
+            yield from child.walk()
+
+    def strip(self, inplace: bool = False, recurse: bool = False) -> Element:
+        """Return copy with all `Data` tokens
+        that only contain whitespace / newlines removed.
+        """
+        element = self
+        if not inplace:
+            element = self.deepcopy()
+        element.reset_children(
+            [
+                e
+                for e in element.children
+                if not (isinstance(e, Data) and e.data.strip() == "")
+            ]
+        )
+        if recurse:
+            for child in element:
+                child.strip(inplace=True, recurse=True)
+        return element
+
+    def find(
+        self,
+        identifier: str | type[Element],
+        attrs: dict | None = None,
+        classes: Iterable[str] | None = None,
+        include_self: bool = False,
+        recurse: bool = True,
+    ) -> Iterator[Element]:
+        """Find all elements that match name and specific attributes."""
+        iterator = self.walk() if recurse else self
+        if include_self:
+            iterator = itertools.chain([self], iterator)
+        if inspect.isclass(identifier):
+            test_func = lambda c: isinstance(c, identifier)  # noqa: E731
+        else:
+            test_func = lambda c: c.name == identifier  # noqa: E731
+        classes = set(classes) if classes is not None else classes
+        for child in iterator:
+            if test_func(child):
+                if classes is not None and not classes.issubset(child.attrs.classes):
+                    continue
+                for key, value in (attrs or {}).items():
+                    if child.attrs[key] != value:
+                        break
+                else:
+                    yield child
+
+
+class Root(Element):
+    """The root of the AST tree."""
+
+    def render(self, **kwargs) -> str:  # type: ignore[override]
+        """Returns a string HTML representation of the structure."""
+        return "".join(child.render(**kwargs) for child in self)
+
+
+class Tag(Element):
+    """Represent xml/html tags under the form: <name key="value" ...> ... </name>."""
+
+    def render(
+        self,
+        tag_overrides: dict[str, Callable[[Element, dict], str]] | None = None,
+        **kwargs,
+    ) -> str:
+        if tag_overrides and self.name in tag_overrides:
+            return tag_overrides[self.name](self, tag_overrides)
+        return (
+            f"<{self.name}{' ' if self.attrs else ''}{self.attrs}>"
+            + "".join(
+                child.render(tag_overrides=tag_overrides, **kwargs) for child in self
+            )
+            + f"</{self.name}>"
+        )
+
+
+class XTag(Element):
+    """Represent XHTML style tags with no children, like `<img src="t.gif" />`"""
+
+    def render(
+        self,
+        tag_overrides: dict[str, Callable[[Element, dict], str]] | None = None,
+        **kwargs,
+    ) -> str:
+        if tag_overrides is not None and self.name in tag_overrides:
+            return tag_overrides[self.name](self, tag_overrides)
+        return f"<{self.name}{' ' if self.attrs else ''}{self.attrs}/>"
+
+
+class VoidTag(Element):
+    """Represent tags with no children, only start tag, like `<img src="t.gif" >`"""
+
+    def render(self, **kwargs) -> str:  # type: ignore[override]
+        return f"<{self.name}{' ' if self.attrs else ''}{self.attrs}>"
+
+
+class TerminalElement(Element):
+    def __init__(self, data: str):
+        super().__init__("")
+        self.data: str = data
+
+    def __repr__(self) -> str:
+        text = self.data
+        if len(text) > 20:
+            text = text[:17] + "..."
+        return f"{self.__class__.__name__}({text!r})"
+
+    def deepcopy(self) -> TerminalElement:
+        """Copy and remove parent."""
+        _copy = self.__class__(self.data)
+        return _copy
+
+
+class Data(TerminalElement):
+    """Represent data inside xml/html documents, like raw text."""
+
+    def render(self, **kwargs) -> str:  # type: ignore[override]
+        return self.data
+
+
+class Declaration(TerminalElement):
+    """Represent declarations, like `<!DOCTYPE html>`"""
+
+    def render(self, **kwargs) -> str:  # type: ignore[override]
+        return f"<!{self.data}>"
+
+
+class Comment(TerminalElement):
+    """Represent HTML comments"""
+
+    def render(self, **kwargs) -> str:  # type: ignore[override]
+        return f"<!--{self.data}-->"
+
+
+class Pi(TerminalElement):
+    """Represent processing instructions like `<?xml-stylesheet ?>`"""
+
+    def render(self, **kwargs) -> str:  # type: ignore[override]
+        return f"<?{self.data}>"
+
+
+class Char(TerminalElement):
+    """Represent character codes like: `&#0`"""
+
+    def render(self, **kwargs) -> str:  # type: ignore[override]
+        return f"&#{self.data};"
+
+
+class Entity(TerminalElement):
+    """Represent entities like `&amp`"""
+
+    def render(self, **kwargs) -> str:  # type: ignore[override]
+        return f"&{self.data};"
+
+
+class Tree:
+    """The engine class to generate the AST tree."""
+
+    def __init__(self, name: str = ""):
+        """Initialise Tree"""
+        self.name = name
+        self.outmost = Root(name)
+        self.stack: deque = deque()
+        self.stack.append(self.outmost)
+
+    def clear(self):
+        """Clear the outmost and stack for a new parsing."""
+        self.outmost = Root(self.name)
+        self.stack.clear()
+        self.stack.append(self.outmost)
+
+    def last(self) -> Element:
+        """Return the last pointer which point to the actual tag scope."""
+        return self.stack[-1]
+
+    def nest_tag(self, name: str, attrs: dict):
+        """Nest a given tag at the bottom of the tree using
+        the last stack's pointer.
+        """
+        pointer = self.stack.pop()
+        item = Tag(name, attrs)
+        pointer.append(item)
+        self.stack.append(pointer)
+        self.stack.append(item)
+
+    def nest_xtag(self, name: str, attrs: dict):
+        """Nest an XTag onto the tree."""
+        top = self.last()
+        item = XTag(name, attrs)
+        top.append(item)
+
+    def nest_vtag(self, name: str, attrs: dict):
+        """Nest a VoidTag onto the tree."""
+        top = self.last()
+        item = VoidTag(name, attrs)
+        top.append(item)
+
+    def nest_terminal(self, klass: type[TerminalElement], data: str):
+        """Nest the data onto the tree."""
+        top = self.last()
+        item = klass(data)
+        top.append(item)
+
+    def enclose(self, name: str):
+        """When a closing tag is found, pop the pointer's scope from the stack,
+        to then point to the earlier scope's tag.
+        """
+        count = 0
+        for ind in reversed(self.stack):
+            count = count + 1
+            if ind.name == name:
+                break
+        else:
+            count = 0
+
+        # It pops all the items which do not match with the closing tag.
+        for _ in range(0, count):
+            self.stack.pop()
+
+
+class HtmlToAst(HTMLParser):
+    """The tokenizer class."""
+
+    # see https://html.spec.whatwg.org/multipage/syntax.html#void-elements
+    void_elements = {
+        "area",
+        "base",
+        "br",
+        "col",
+        "embed",
+        "hr",
+        "img",
+        "input",
+        "link",
+        "meta",
+        "param",
+        "source",
+        "track",
+        "wbr",
+    }
+
+    def __init__(self, name: str = "", convert_charrefs: bool = False):
+        super().__init__(convert_charrefs=convert_charrefs)
+        self.struct = Tree(name)
+
+    def feed(self, source: str) -> Root:  # type: ignore[override]
+        """Parse the source string."""
+        self.struct.clear()
+        super().feed(source)
+        return self.struct.outmost
+
+    def handle_starttag(self, name: str, attr):
+        """When found an opening tag then nest it onto the tree."""
+        if name in self.void_elements:
+            self.struct.nest_vtag(name, attr)
+        else:
+            self.struct.nest_tag(name, attr)
+
+    def handle_startendtag(self, name: str, attr):
+        """When found a XHTML tag style then nest it up to the tree."""
+        self.struct.nest_xtag(name, attr)
+
+    def handle_endtag(self, name: str):
+        """When found a closing tag then makes it point to the right scope."""
+        if name not in self.void_elements:
+            self.struct.enclose(name)
+
+    def handle_data(self, data: str):
+        """Nest data onto the tree."""
+        self.struct.nest_terminal(Data, data)
+
+    def handle_decl(self, decl: str):
+        self.struct.nest_terminal(Declaration, decl)
+
+    def unknown_decl(self, decl: str):
+        self.struct.nest_terminal(Declaration, decl)
+
+    def handle_charref(self, data: str):
+        self.struct.nest_terminal(Char, data)
+
+    def handle_entityref(self, data: str):
+        self.struct.nest_terminal(Entity, data)
+
+    def handle_pi(self, data: str):
+        self.struct.nest_terminal(Pi, data)
+
+    def handle_comment(self, data: str):
+        self.struct.nest_terminal(Comment, data)
+
+
+def tokenize_html(text: str, name: str = "", convert_charrefs: bool = False) -> Root:
+    parser = HtmlToAst(name, convert_charrefs=convert_charrefs)
+    return parser.feed(text)