Source code for schrodinger.infra.qt_message_handler

"""
A Qt message handler that suppresses debugging and info output as well as any
warnings or errors that we can't otherwise fix.
"""
from schrodinger.Qt import QtCore

_MSG_TYPES_TO_SUPPRESS = {QtCore.QtDebugMsg, QtCore.QtInfoMsg}
_MESSAGES_TO_SUPPRESS = {
    # This warning can come from matplotlib 2.2.4, so we suppress it until
    # we upgrade to matplotlib 3
    "Attribute Qt::AA_EnableHighDpiScaling must be set before QCoreApplication "
    "is created.",
}
_OLD_HANDLER = None
_HANDLER_INSTALLED = False


def install_handler():
    """
    Install the message handler.  Is a no-op if called more than once.
    """
    global _OLD_HANDLER, _HANDLER_INSTALLED
    if _HANDLER_INSTALLED:
        return
    _OLD_HANDLER = QtCore.qInstallMessageHandler(_handler)
    _HANDLER_INSTALLED = True


def _handler(msg_type, context, msg):
    """
    Handle Qt messages.  Message types in _MSG_TYPES_TO_SUPPRESS and messages in
    _MESSAGES_TO_SUPPRESS will be ignored.  All other messages will be sent to
    the previous custom handler if one exists.  If there's no previous custom
    handler, then the messages will be printed to standard output (which is the
    default Qt behavior).

    :param msg_type: The message type.  Given as an integer representing a
        QtCore.QtMsgType enum value.
    :type msg_type: int

    :param context: The context of the message
    :type context: QtMessageLogContext

    :param msg: The message itself
    :type msg: str
    """
    if msg_type in _MSG_TYPES_TO_SUPPRESS or msg in _MESSAGES_TO_SUPPRESS:
        return
    elif _OLD_HANDLER is not None:
        _OLD_HANDLER(msg_type, context, msg)
    else:
        print(msg)