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scripts: Reworked dbgmtree.py, adopted Mtree, Mdir, etc

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This is where the high-level structure of littlefs starts to reveal
itself.

This is also where a lot of really annoying Mtree vs Btree API questions
come to a head, like should Mtree.lookup return an Mdir or an Rattr?
What about Btree.lookup? What gets included in the returned path in all
of these? Well, at least this is an interesting exercise in rethinking
littlefs's internal APIs...

New classes:

- Mid - A representation of littlefs's metadata ids. I've just gone
  ahead and included the block_size-dependent mbits as a field in every
  Mid instance to try to make Mid operations easier.

  It's not like we care about one extra word of storage in Python.

- Mdir - Again, we intentionally _don't_ inherit Rbyd to try to reduce
  type errors, though Mdirs really are just Rbyds in this design.

- Mtree - The skeleton of littlefs. Tricky bits include traversing the
  mroot chain and handling mroot-inlined mdirs. Note mroots are included
  in the mdir/mid iteration methods.

Getting the tree renderers all working again was a real pain in the ass.
This commit is contained in:
Christopher Haster
2025-03-24 01:36:58 -05:00
parent 0e2a302d35
commit 582f92d073
3 changed files with 2047 additions and 1242 deletions
Download Patch File Download Diff File Expand all files Collapse all files
scripts/dbgrbyd.py
+70 -44
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@@ -266,13 +266,11 @@ def tagrepr(tag, weight=None, size=None, off=None):
' %d' % size if size is not None else '')
# tree branches are an abstract thing for tree rendering
class TreeBranch:
def __init__(self, a, b, depth=0, color='b'):
class TreeBranch(co.namedtuple('TreeBranch', ['a', 'b', 'depth', 'color'])):
__slots__ = ()
def __new__(cls, a, b, depth=0, color='b'):
# a and b are context specific
self.a = a
self.b = b
self.depth = depth
self.color = color
return super().__new__(cls, a, b, depth, color)
def __repr__(self):
return '%s(%s, %s, %s, %s)' % (
@@ -282,16 +280,6 @@ class TreeBranch:
self.depth,
self.color)
def __eq__(self, other):
return ((self.a, self.b, self.depth, self.color)
== (other.a, other.b, other.depth, other.color))
def __ne__(self, other):
return not self.__eq__(other)
def __hash__(self):
return hash((self.a, self.b, self.depth))
def treerepr(tree, x, depth=None, color=False):
# find the max depth from the tree
if depth is None:
@@ -382,9 +370,9 @@ class Rattr:
return len(self.data)
def __repr__(self):
return '<%s %s>' % (self.__class__.__name__, self.tagrepr())
return '<%s %s>' % (self.__class__.__name__, self)
def tagrepr(self):
def __str__(self):
return tagrepr(self.tag, self.weight, self.size)
def __iter__(self):
@@ -421,9 +409,9 @@ class Ralt:
return self.toff - self.jump
def __repr__(self):
return '<%s %s>' % (self.__class__.__name__, self.tagrepr())
return '<%s %s>' % (self.__class__.__name__, self)
def tagrepr(self):
def __str__(self):
return tagrepr(self.tag, self.weight, self.jump, self.toff)
def __iter__(self):
@@ -632,7 +620,7 @@ class Rbyd:
gcksumdelta=gcksumdelta,
corrupt=not trunk_)
def lookupnext(self, rid=-1, tag=None, *,
def lookupnext(self, rid, tag=None, *,
path=False):
if not self:
return None, None, *(([],) if path else ())
@@ -710,21 +698,26 @@ class Rbyd:
self.data[j+d:j+d+jump]),
*((path_,) if path else ()))
def lookup(self, rid, tag=None, mask=None, *,
def lookup_(self, rid, tag=None, mask=None, *,
path=False):
if tag is None:
tag, mask = 0, 0xffff
if mask is None:
mask = 0
rid_, rattr_, *path_ = self.lookupnext(rid, tag & ~(mask or 0),
rid_, rattr_, *path_ = self.lookupnext(rid, tag & ~mask,
path=path)
if (rid_ is None
or rid_ != rid
or (rattr_.tag_ & ~(mask or 0)) != (tag & ~(mask or 0))):
if path:
return None, *path_
else:
return None
or (rattr_.tag & ~mask) != (tag & ~mask)):
return None, *path_
return rattr_, *path_
def lookup(self, rid, tag=None, mask=None, *,
path=False):
rattr_, *path_ = self.lookup_(rid, tag, mask,
path=path)
if path:
return rattr_, *path_
else:
@@ -740,26 +733,22 @@ class Rbyd:
if not isinstance(key, tuple):
key = (key,)
v = self.lookup(*key)
if isinstance(v, tuple):
return v[0] is not None
else:
return v is not None
return self.lookup_(*key)[0] is not None
def rids(self, *,
path=False):
rid = -1
while True:
rid, rattr, *path_ = self.lookupnext(rid,
rid, name, *path_ = self.lookupnext(rid,
path=path)
# found end of tree?
if rid is None:
break
yield rid, rattr, *path_
yield rid, name, *path_
rid += 1
def rattrs(self, rid=None, *,
def rattrs_(self, rid=None, *,
path=False):
if rid is None:
rid, tag = -1, 0
@@ -781,11 +770,21 @@ class Rbyd:
if rid_ is None or rid_ != rid:
break
yield rattr, *path_
tag = rattr.tag
def rattrs(self, rid=None, *,
path=False):
if rid is None:
yield from self.rattrs_(rid,
path=path)
else:
for rattr, *path_ in self.rattrs_(rid,
path=path):
if path:
yield rattr, *path_
else:
yield rattr
tag = rattr.tag
def __iter__(self):
return self.rattrs()
@@ -823,8 +822,8 @@ class Rbyd:
return best
# create tree representation for debugging
def tree(self, **args):
# create an rbyd tree for debugging
def _tree_rtree(self, **args):
trunks = co.defaultdict(lambda: (-1, 0))
alts = co.defaultdict(lambda: {})
@@ -913,6 +912,25 @@ class Rbyd:
return tree
# create a btree tree for debugging
def _tree_btree(self, **args):
# for rbyds this is just a pointer to ever rid
tree = set()
root = None
for rid, name in self.rids():
b = (rid, name.tag)
if root is None:
root = b
tree.add(TreeBranch(root, b))
return tree
# create tree representation for debugging
def tree(self, **args):
if args.get('tree_btree'):
return self._tree_btree(**args)
else:
return self._tree_rtree(**args)
def dbg_log(rbyd, *,
block_size,
@@ -1291,9 +1309,11 @@ def dbg_tree(rbyd, *,
data = rbyd.data
# precompute tree
# precompute tree renderings
t_width = 0
if args.get('tree') or args.get('tree_rbyd'):
if (args.get('tree')
or args.get('tree_rbyd')
or args.get('tree_btree')):
tree = rbyd.tree(**args)
# find the max depth from the tree
@@ -1309,13 +1329,15 @@ def dbg_tree(rbyd, *,
print('%08x: %s%*s %-*s %s' % (
rattr.toff,
treerepr(tree, (rid, rattr.tag), t_depth, color)
if args.get('tree') or args.get('tree_rbyd')
if (args.get('tree')
or args.get('tree_rbyd')
or args.get('tree_btree'))
else '',
2*w_width+1, '%d-%d' % (rid-(rattr.weight-1), rid)
if rattr.weight > 1
else rid if rattr.weight > 0 or i == 0
else '',
21+w_width, rattr.tagrepr(),
21+w_width, rattr,
next(xxd(rattr.data[:8], 8), '')
if not args.get('raw')
and not args.get('no_truncate')
@@ -1375,6 +1397,7 @@ def main(disk, blocks=None, *,
bd = Bd(f, block_size, block_count)
rbyd = Rbyd.fetch(bd, blocks)
# print some information about the rbyd
print('rbyd %s w%d, rev %08x, size %d, cksum %08x' % (
rbyd.addr(),
rbyd.weight,
@@ -1448,11 +1471,14 @@ if __name__ == "__main__":
'-t', '--tree',
action='store_true',
help="Show the rbyd tree.")
# TODO adopt this rename in all scripts
parser.add_argument(
'-R', '--tree-rbyd',
action='store_true',
help="Show the full rbyd tree.")
parser.add_argument(
'-B', '--tree-btree',
action='store_true',
help="Show a simplified btree tree.")
parser.add_argument(
'-j', '--jumps',
action='store_true',