Class Snapshot

Lib/tracemalloc.py:415–548

Snapshot of traces of memory blocks allocated by Python.

class Snapshot:
    """
    Snapshot of traces of memory blocks allocated by Python.
    """

    def __init__(self, traces, traceback_limit):
        # traces is a tuple of trace tuples: see _Traces constructor for
        # the exact format
        self.traces = _Traces(traces)
        self.traceback_limit = traceback_limit

    def dump(self, filename):
        """
        Write the snapshot into a file.
        """
        with open(filename, "wb") as fp:
            pickle.dump(self, fp, pickle.HIGHEST_PROTOCOL)

    @staticmethod
    def load(filename):
        """
        Load a snapshot from a file.
        """
        with open(filename, "rb") as fp:
            return pickle.load(fp)

    def _filter_trace(self, include_filters, exclude_filters, trace):
        if include_filters:
            if not any(trace_filter._match(trace)
                       for trace_filter in include_filters):
                return False
        if exclude_filters:
            if any(not trace_filter._match(trace)
                   for trace_filter in exclude_filters):
                return False
        return True

    def filter_traces(self, filters):
        """
        Create a new Snapshot instance with a filtered traces sequence, filters
        is a list of Filter or DomainFilter instances.  If filters is an empty
        list, return a new Snapshot instance with a copy of the traces.
        """
        if not isinstance(filters, Iterable):
            raise TypeError("filters must be a list of filters, not %s"
                            % type(filters).__name__)
        if filters:
            include_filters = []
            exclude_filters = []
            for trace_filter in filters:
                if trace_filter.inclusive:
                    include_filters.append(trace_filter)
                else:
                    exclude_filters.append(trace_filter)
            new_traces = [trace for trace in self.traces._traces
                          if self._filter_trace(include_filters,
                                                exclude_filters,
                                                trace)]