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- """Object representations for debugging purposes. Unlike the default
- repr, these expose more information and produce HTML instead of ASCII.
- Together with the CSS and JavaScript of the debugger this gives a
- colorful and more compact output.
- """
- import codecs
- import re
- import sys
- import typing as t
- from collections import deque
- from html import escape
- from traceback import format_exception_only
- missing = object()
- _paragraph_re = re.compile(r"(?:\r\n|\r|\n){2,}")
- RegexType = type(_paragraph_re)
- HELP_HTML = """\
- <div class=box>
- <h3>%(title)s</h3>
- <pre class=help>%(text)s</pre>
- </div>\
- """
- OBJECT_DUMP_HTML = """\
- <div class=box>
- <h3>%(title)s</h3>
- %(repr)s
- <table>%(items)s</table>
- </div>\
- """
- def debug_repr(obj: object) -> str:
- """Creates a debug repr of an object as HTML string."""
- return DebugReprGenerator().repr(obj)
- def dump(obj: object = missing) -> None:
- """Print the object details to stdout._write (for the interactive
- console of the web debugger.
- """
- gen = DebugReprGenerator()
- if obj is missing:
- rv = gen.dump_locals(sys._getframe(1).f_locals)
- else:
- rv = gen.dump_object(obj)
- sys.stdout._write(rv) # type: ignore
- class _Helper:
- """Displays an HTML version of the normal help, for the interactive
- debugger only because it requires a patched sys.stdout.
- """
- def __repr__(self) -> str:
- return "Type help(object) for help about object."
- def __call__(self, topic: t.Optional[t.Any] = None) -> None:
- if topic is None:
- sys.stdout._write(f"<span class=help>{self!r}</span>") # type: ignore
- return
- import pydoc
- pydoc.help(topic)
- rv = sys.stdout.reset() # type: ignore
- if isinstance(rv, bytes):
- rv = rv.decode("utf-8", "ignore")
- paragraphs = _paragraph_re.split(rv)
- if len(paragraphs) > 1:
- title = paragraphs[0]
- text = "\n\n".join(paragraphs[1:])
- else:
- title = "Help"
- text = paragraphs[0]
- sys.stdout._write(HELP_HTML % {"title": title, "text": text}) # type: ignore
- helper = _Helper()
- def _add_subclass_info(
- inner: str, obj: object, base: t.Union[t.Type, t.Tuple[t.Type, ...]]
- ) -> str:
- if isinstance(base, tuple):
- for cls in base:
- if type(obj) is cls:
- return inner
- elif type(obj) is base:
- return inner
- module = ""
- if obj.__class__.__module__ not in ("__builtin__", "exceptions"):
- module = f'<span class="module">{obj.__class__.__module__}.</span>'
- return f"{module}{type(obj).__name__}({inner})"
- def _sequence_repr_maker(
- left: str, right: str, base: t.Type, limit: int = 8
- ) -> t.Callable[["DebugReprGenerator", t.Iterable, bool], str]:
- def proxy(self: "DebugReprGenerator", obj: t.Iterable, recursive: bool) -> str:
- if recursive:
- return _add_subclass_info(f"{left}...{right}", obj, base)
- buf = [left]
- have_extended_section = False
- for idx, item in enumerate(obj):
- if idx:
- buf.append(", ")
- if idx == limit:
- buf.append('<span class="extended">')
- have_extended_section = True
- buf.append(self.repr(item))
- if have_extended_section:
- buf.append("</span>")
- buf.append(right)
- return _add_subclass_info("".join(buf), obj, base)
- return proxy
- class DebugReprGenerator:
- def __init__(self) -> None:
- self._stack: t.List[t.Any] = []
- list_repr = _sequence_repr_maker("[", "]", list)
- tuple_repr = _sequence_repr_maker("(", ")", tuple)
- set_repr = _sequence_repr_maker("set([", "])", set)
- frozenset_repr = _sequence_repr_maker("frozenset([", "])", frozenset)
- deque_repr = _sequence_repr_maker(
- '<span class="module">collections.</span>deque([', "])", deque
- )
- def regex_repr(self, obj: t.Pattern) -> str:
- pattern = repr(obj.pattern)
- pattern = codecs.decode(pattern, "unicode-escape", "ignore") # type: ignore
- pattern = f"r{pattern}"
- return f're.compile(<span class="string regex">{pattern}</span>)'
- def string_repr(self, obj: t.Union[str, bytes], limit: int = 70) -> str:
- buf = ['<span class="string">']
- r = repr(obj)
- # shorten the repr when the hidden part would be at least 3 chars
- if len(r) - limit > 2:
- buf.extend(
- (
- escape(r[:limit]),
- '<span class="extended">',
- escape(r[limit:]),
- "</span>",
- )
- )
- else:
- buf.append(escape(r))
- buf.append("</span>")
- out = "".join(buf)
- # if the repr looks like a standard string, add subclass info if needed
- if r[0] in "'\"" or (r[0] == "b" and r[1] in "'\""):
- return _add_subclass_info(out, obj, (bytes, str))
- # otherwise, assume the repr distinguishes the subclass already
- return out
- def dict_repr(
- self,
- d: t.Union[t.Dict[int, None], t.Dict[str, int], t.Dict[t.Union[str, int], int]],
- recursive: bool,
- limit: int = 5,
- ) -> str:
- if recursive:
- return _add_subclass_info("{...}", d, dict)
- buf = ["{"]
- have_extended_section = False
- for idx, (key, value) in enumerate(d.items()):
- if idx:
- buf.append(", ")
- if idx == limit - 1:
- buf.append('<span class="extended">')
- have_extended_section = True
- buf.append(
- f'<span class="pair"><span class="key">{self.repr(key)}</span>:'
- f' <span class="value">{self.repr(value)}</span></span>'
- )
- if have_extended_section:
- buf.append("</span>")
- buf.append("}")
- return _add_subclass_info("".join(buf), d, dict)
- def object_repr(
- self, obj: t.Optional[t.Union[t.Type[dict], t.Callable, t.Type[list]]]
- ) -> str:
- r = repr(obj)
- return f'<span class="object">{escape(r)}</span>'
- def dispatch_repr(self, obj: t.Any, recursive: bool) -> str:
- if obj is helper:
- return f'<span class="help">{helper!r}</span>'
- if isinstance(obj, (int, float, complex)):
- return f'<span class="number">{obj!r}</span>'
- if isinstance(obj, str) or isinstance(obj, bytes):
- return self.string_repr(obj)
- if isinstance(obj, RegexType):
- return self.regex_repr(obj)
- if isinstance(obj, list):
- return self.list_repr(obj, recursive)
- if isinstance(obj, tuple):
- return self.tuple_repr(obj, recursive)
- if isinstance(obj, set):
- return self.set_repr(obj, recursive)
- if isinstance(obj, frozenset):
- return self.frozenset_repr(obj, recursive)
- if isinstance(obj, dict):
- return self.dict_repr(obj, recursive)
- if isinstance(obj, deque):
- return self.deque_repr(obj, recursive)
- return self.object_repr(obj)
- def fallback_repr(self) -> str:
- try:
- info = "".join(format_exception_only(*sys.exc_info()[:2]))
- except Exception:
- info = "?"
- return (
- '<span class="brokenrepr">'
- f"<broken repr ({escape(info.strip())})></span>"
- )
- def repr(self, obj: object) -> str:
- recursive = False
- for item in self._stack:
- if item is obj:
- recursive = True
- break
- self._stack.append(obj)
- try:
- try:
- return self.dispatch_repr(obj, recursive)
- except Exception:
- return self.fallback_repr()
- finally:
- self._stack.pop()
- def dump_object(self, obj: object) -> str:
- repr = None
- items: t.Optional[t.List[t.Tuple[str, str]]] = None
- if isinstance(obj, dict):
- title = "Contents of"
- items = []
- for key, value in obj.items():
- if not isinstance(key, str):
- items = None
- break
- items.append((key, self.repr(value)))
- if items is None:
- items = []
- repr = self.repr(obj)
- for key in dir(obj):
- try:
- items.append((key, self.repr(getattr(obj, key))))
- except Exception:
- pass
- title = "Details for"
- title += f" {object.__repr__(obj)[1:-1]}"
- return self.render_object_dump(items, title, repr)
- def dump_locals(self, d: t.Dict[str, t.Any]) -> str:
- items = [(key, self.repr(value)) for key, value in d.items()]
- return self.render_object_dump(items, "Local variables in frame")
- def render_object_dump(
- self, items: t.List[t.Tuple[str, str]], title: str, repr: t.Optional[str] = None
- ) -> str:
- html_items = []
- for key, value in items:
- html_items.append(f"<tr><th>{escape(key)}<td><pre class=repr>{value}</pre>")
- if not html_items:
- html_items.append("<tr><td><em>Nothing</em>")
- return OBJECT_DUMP_HTML % {
- "title": escape(title),
- "repr": f"<pre class=repr>{repr if repr else ''}</pre>",
- "items": "\n".join(html_items),
- }
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