Class TermInfo

Lib/_pyrepl/terminfo.py:320–438

@dataclass
class TermInfo:
    terminal_name: str | bytes | None
    fallback: bool = True

    _capabilities: dict[str, bytes] = field(default_factory=dict)

    def __post_init__(self) -> None:
        """Initialize terminal capabilities for the given terminal type.

        Based on ncurses implementation in:
        - ncurses/tinfo/lib_setup.c:setupterm() and _nc_setupterm()
        - ncurses/tinfo/lib_setup.c:TINFO_SETUP_TERM()

        This version first attempts to read terminfo database files like ncurses,
        then, if `fallback` is True, falls back to hardcoded capabilities for
        common terminal types.
        """
        # If termstr is None or empty, try to get from environment
        if not self.terminal_name:
            self.terminal_name = os.environ.get("TERM") or "ANSI"

        if isinstance(self.terminal_name, bytes):
            self.terminal_name = self.terminal_name.decode("ascii")

        try:
            self._parse_terminfo_file(self.terminal_name)
        except (OSError, ValueError):
            if not self.fallback:
                raise

            term_type = _TERM_ALIASES.get(
                self.terminal_name, self.terminal_name
            )
            if term_type not in _TERMINAL_CAPABILITIES:
                term_type = "dumb"
            self._capabilities = _TERMINAL_CAPABILITIES[term_type].copy()

    def _parse_terminfo_file(self, terminal_name: str) -> None:
        """Parse a terminfo file.

        Populate the _capabilities dict for easy retrieval

        Based on ncurses implementation in:
        - ncurses/tinfo/read_entry.c:_nc_read_termtype()
        - ncurses/tinfo/read_entry.c:_nc_read_file_entry()
        - ncurses/tinfo/lib_ti.c:tigetstr()
        """
        data = _read_terminfo_file(terminal_name)
        too_short = f"TermInfo file for {terminal_name!r} too short"
        offset = 12
        if len(data) < offset:
            raise ValueError(too_short)

        magic, name_size, bool_count, num_count, str_count, str_size = (
            struct.unpack("<Hhhhhh", data[:offset])
        )

        if magic == MAGIC16: