Class Squeezer

Lib/idlelib/squeezer.py:200–335

Replace long outputs in the shell with a simple button. This avoids IDLE's shell slowing down considerably, and even becoming completely unresponsive, when very long outputs are written.

class Squeezer:
    """Replace long outputs in the shell with a simple button.

    This avoids IDLE's shell slowing down considerably, and even becoming
    completely unresponsive, when very long outputs are written.
    """
    @classmethod
    def reload(cls):
        """Load class variables from config."""
        cls.auto_squeeze_min_lines = idleConf.GetOption(
            "main", "PyShell", "auto-squeeze-min-lines",
            type="int", default=50,
        )

    def __init__(self, editwin):
        """Initialize settings for Squeezer.

        editwin is the shell's Editor window.
        self.text is the editor window text widget.
        self.base_test is the actual editor window Tk text widget, rather than
            EditorWindow's wrapper.
        self.expandingbuttons is the list of all buttons representing
            "squeezed" output.
        """
        self.editwin = editwin
        self.text = text = editwin.text

        # Get the base Text widget of the PyShell object, used to change
        # text before the iomark. PyShell deliberately disables changing
        # text before the iomark via its 'text' attribute, which is
        # actually a wrapper for the actual Text widget. Squeezer,
        # however, needs to make such changes.
        self.base_text = editwin.per.bottom

        # Twice the text widget's border width and internal padding;
        # pre-calculated here for the get_line_width() method.
        self.window_width_delta = 2 * (
            int(text.cget('border')) +
            int(text.cget('padx'))
        )

        self.expandingbuttons = []

        # Replace the PyShell instance's write method with a wrapper,
        # which inserts an ExpandingButton instead of a long text.
        def mywrite(s, tags=(), write=editwin.write):
            # Only auto-squeeze text which has just the "stdout" tag.
            if tags != "stdout":
                return write(s, tags)

            # Only auto-squeeze text with at least the minimum
            # configured number of lines.
            auto_squeeze_min_lines = self.auto_squeeze_min_lines
            # First, a very quick check to skip very short texts.
            if len(s) < auto_squeeze_min_lines:
                return write(s, tags)
            # Now the full line-count check.
            numoflines = self.count_lines(s)