Current File : //usr/share/gdb/python/gdb/dap/frames.py
# Copyright 2022-2024 Free Software Foundation, Inc.
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import itertools
import gdb
from gdb.frames import frame_iterator
from .startup import in_gdb_thread
# A list of all the frames we've reported. A frame's index in the
# list is its ID. We don't use a hash here because frames are not
# hashable.
_all_frames = []
# Map from a global thread ID to a memoizing frame iterator.
_iter_map = {}
# Clear all the frame IDs.
@in_gdb_thread
def _clear_frame_ids(evt):
global _all_frames
_all_frames = []
global _iter_map
_iter_map = {}
# Clear the frame ID map whenever the inferior runs.
gdb.events.cont.connect(_clear_frame_ids)
@in_gdb_thread
def frame_for_id(id):
"""Given a frame identifier ID, return the corresponding frame."""
global _all_frames
return _all_frames[id]
@in_gdb_thread
def select_frame(id):
"""Given a frame identifier ID, select the corresponding frame."""
frame = frame_for_id(id)
frame.inferior_frame().select()
# A simple memoizing iterator. Note that this is not very robust.
# For example, you can't start two copies of the iterator and then
# alternate fetching items from each. Instead, it implements just
# what is needed for the current callers.
class _MemoizingIterator:
def __init__(self, iterator):
self.iterator = iterator
self.seen = []
def __iter__(self):
# First the memoized items.
for item in self.seen:
yield item
# Now memoize new items.
for item in self.iterator:
self.seen.append(item)
yield item
# A generator that fetches frames and pairs them with a frame ID. It
# yields tuples of the form (ID, ELIDED, FRAME), where ID is the
# generated ID, ELIDED is a boolean indicating if the frame should be
# elided, and FRAME is the frame itself. This approach lets us
# memoize the result and assign consistent IDs, independent of how
# "includeAll" is set in the request.
@in_gdb_thread
def _frame_id_generator():
try:
base_iterator = frame_iterator(gdb.newest_frame(), 0, -1)
except gdb.error:
base_iterator = ()
# Helper function to assign an ID to a frame.
def get_id(frame):
global _all_frames
num = len(_all_frames)
_all_frames.append(frame)
return num
def yield_frames(iterator, for_elided):
for frame in iterator:
# Unfortunately the frame filter docs don't describe
# whether the elided frames conceptually come before or
# after the eliding frame. Here we choose after.
yield (get_id(frame), for_elided, frame)
elided = frame.elided()
if elided is not None:
yield from yield_frames(frame.elided(), True)
yield from yield_frames(base_iterator, False)
# Return the memoizing frame iterator for the selected thread.
@in_gdb_thread
def _get_frame_iterator():
thread_id = gdb.selected_thread().global_num
global _iter_map
if thread_id not in _iter_map:
_iter_map[thread_id] = _MemoizingIterator(_frame_id_generator())
return _iter_map[thread_id]
# A helper function that creates an iterable that returns (ID, FRAME)
# pairs. It uses the memoizing frame iterator, but also handles the
# "includeAll" member of StackFrameFormat.
@in_gdb_thread
def dap_frame_generator(frame_low, levels, include_all):
"""A generator that yields identifiers and frames.
Each element is a pair of the form (ID, FRAME).
ID is the internally-assigned frame ID.
FRAME is a FrameDecorator of some kind.
Arguments are as to the stackTrace request."""
base_iterator = _get_frame_iterator()
if not include_all:
base_iterator = itertools.filterfalse(lambda item: item[1], base_iterator)
if levels == 0:
# Zero means all remaining frames.
frame_high = None
else:
frame_high = frame_low + levels
base_iterator = itertools.islice(base_iterator, frame_low, frame_high)
for ident, _, frame in base_iterator:
yield (ident, frame)
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