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import sys, traceback
from ..Qt import QtWidgets, QtGui
class StackWidget(QtWidgets.QTreeWidget):
def __init__(self, parent=None):
QtWidgets.QTreeWidget.__init__(self, parent)
self.setAlternatingRowColors(True)
self.setHeaderHidden(True)
def selectedFrame(self):
"""Return the currently selected stack frame (or None if there is no selection)
"""
sel = self.selectedItems()
if len(sel) == 0:
return None
else:
return sel[0].frame
def clear(self):
QtWidgets.QTreeWidget.clear(self)
self.frames = []
def setException(self, exc=None, lastFrame=None):
"""Display an exception chain with its tracebacks and call stack.
"""
if exc is None:
exc = sys.exc_info()[1]
self.clear()
exceptions = exceptionChain(exc)
for ex, cause in exceptions:
stackFrames, tbFrames = stacksFromTraceback(ex.__traceback__, lastFrame=lastFrame)
catchMsg = textItem("Exception caught here")
excStr = ''.join(traceback.format_exception_only(type(ex), ex)).strip()
items = makeItemTree(stackFrames + [catchMsg] + tbFrames, excStr)
self.addTopLevelItem(items[0])
if cause is not None:
if cause == 'cause':
causeItem = textItem("The above exception was the direct cause of the following exception:")
elif cause == 'context':
causeItem = textItem("During handling of the above exception, another exception occurred:")
self.addTopLevelItem(causeItem)
items[0].setExpanded(True)
def setStack(self, frame=None, expand=True, lastFrame=None):
"""Display a call stack and exception traceback.
This allows the user to probe the contents of any frame in the given stack.
*frame* may either be a Frame instance or None, in which case the current
frame is retrieved from ``sys._getframe()``.
If *tb* is provided then the frames in the traceback will be appended to
the end of the stack list. If *tb* is None, then sys.exc_info() will
be checked instead.
"""
if frame is None:
frame = sys._getframe().f_back
self.clear()
stack = stackFromFrame(frame, lastFrame=lastFrame)
items = makeItemTree(stack, "Call stack")
self.addTopLevelItem(items[0])
if expand:
items[0].setExpanded(True)
def stackFromFrame(frame, lastFrame=None):
"""Return (text, stack_frame) for the entire stack ending at *frame*
If *lastFrame* is given and present in the stack, then the stack is truncated
at that frame.
"""
lines = traceback.format_stack(frame)
frames = []
while frame is not None:
frames.insert(0, frame)
frame = frame.f_back
if lastFrame is not None and lastFrame in frames:
frames = frames[:frames.index(lastFrame)+1]
return list(zip(lines[:len(frames)], frames))
def stacksFromTraceback(tb, lastFrame=None):
"""Return (text, stack_frame) for a traceback and the stack preceding it
If *lastFrame* is given and present in the stack, then the stack is truncated
at that frame.
"""
# get stack before tb
stack = stackFromFrame(tb.tb_frame.f_back if tb is not None else lastFrame)
if tb is None:
return stack, []
# walk to last frame of traceback
lines = traceback.format_tb(tb)
frames = []
while True:
frames.append(tb.tb_frame)
if tb.tb_next is None or tb.tb_frame is lastFrame:
break
tb = tb.tb_next
return stack, list(zip(lines[:len(frames)], frames))
def makeItemTree(stack, title):
topItem = QtWidgets.QTreeWidgetItem([title])
topItem.frame = None
font = topItem.font(0)
font.setWeight(font.Weight.Bold)
topItem.setFont(0, font)
items = [topItem]
for entry in stack:
if isinstance(entry, QtWidgets.QTreeWidgetItem):
item = entry
else:
text, frame = entry
item = QtWidgets.QTreeWidgetItem([text.rstrip()])
item.frame = frame
topItem.addChild(item)
items.append(item)
return items
def exceptionChain(exc):
"""Return a list of (exception, 'cause'|'context') pairs for exceptions
leading up to *exc*
"""
exceptions = [(exc, None)]
while True:
# walk through chained exceptions
if exc.__cause__ is not None:
exc = exc.__cause__
exceptions.insert(0, (exc, 'cause'))
elif exc.__context__ is not None and exc.__suppress_context__ is False:
exc = exc.__context__
exceptions.insert(0, (exc, 'context'))
else:
break
return exceptions
def textItem(text):
"""Return a tree item with no associated stack frame and a darker background color
"""
item = QtWidgets.QTreeWidgetItem([text])
item.frame = None
item.setBackground(0, QtGui.QBrush(QtGui.QColor(220, 220, 220)))
item.setForeground(0, QtGui.QBrush(QtGui.QColor(0, 0, 0)))
item.setChildIndicatorPolicy(item.ChildIndicatorPolicy.DontShowIndicator)
return item
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