mercurial/dirstateutils/v2.py
91	This should go in the previous changesets.
264–272	This block should go in the `if len(map) ==0:` block
306	This probably deserve that we check `any_tracked`¹ here. [1] introduced in a parallel series
314	can probably be a `<` for clarity.

Diff	ID	Description	Created	Lint	Unit
Base		Base
Diff 1	30446		Oct 1 2021, 3:18 AM	★	★
Diff 2	30500		Oct 1 2021, 9:51 AM	★	★
Diff 3	30616		Oct 3 2021, 7:45 AM	★	★
Diff 4	30687		Oct 8 2021, 8:06 AM	★	★
Diff 5	30690		Oct 8 2021, 12:01 PM	★	★
Diff 6	30760		Oct 12 2021, 2:03 PM	★	★
Diff 7	30775		Oct 13 2021, 1:24 PM	★	★
Diff 8	30798	rHG7e78c72ee3ea436d6d366da05861a0d0b37cba30	Jul 22 2021, 11:31 AM	★	★

Commit	Parents	Author	Summary	Date
66072cd7f776	9ba6eeb9267b	Raphaël Gomès		Jul 22 2021, 11:31 AM

Status	Author	Revision
Closed	marmoute	D11668 dirstate-v2: add an option to prevent unintentional slow dirstate-v2
Closed	SimonSapin	D11520 dirstate-v2: Add support when Rust is not enabled
Closed	SimonSapin	D11519 dirstate-v2: Initial Python serializer
Closed	SimonSapin	D11518 dirstate-v2: initial Python parser
Closed	SimonSapin	D11621 dirstate: Move more methods to the _dirstatemapcommon base class
Closed	SimonSapin	D11655 dirstate-v2: Add storage space for nanoseconds precision in file mtimes
Closed	SimonSapin	D11654 status: Extract TruncatedTimestamp from fs::Metadata without SystemTime

Diff 30760

mercurial/cext/parsers.c

	!(self->flags & dirstate_flag_wc_tracked) \|\|			!(self->flags & dirstate_flag_wc_tracked) \|\|
	(self->flags & dirstate_flag_p2_info)) {			(self->flags & dirstate_flag_p2_info)) {
	return ambiguous_time;			return ambiguous_time;
	} else {			} else {
	return self->mtime;			return self->mtime;
	}			}
	}			}

				static PyObject dirstate_item_v2_data(dirstateItemObject self)
				{
				return Py_BuildValue("Biii", self->flags, self->mode, self->size,
				self->mtime);
				};

	static PyObject dirstate_item_v1_state(dirstateItemObject self)			static PyObject dirstate_item_v1_state(dirstateItemObject self)
	{			{
	char state = dirstate_item_c_v1_state(self);			char state = dirstate_item_c_v1_state(self);
	return PyBytes_FromStringAndSize(&state, 1);			return PyBytes_FromStringAndSize(&state, 1);
	};			};

	static PyObject dirstate_item_v1_mode(dirstateItemObject self)			static PyObject dirstate_item_v1_mode(dirstateItemObject self)
	{			{
	dirstate_flag_has_meaningful_mtime);			dirstate_flag_has_meaningful_mtime);
	self->mode = 0;			self->mode = 0;
	self->mtime = 0;			self->mtime = 0;
	self->size = 0;			self->size = 0;
	}			}
	Py_RETURN_NONE;			Py_RETURN_NONE;
	}			}
	static PyMethodDef dirstate_item_methods[] = {			static PyMethodDef dirstate_item_methods[] = {
				{"v2_data", (PyCFunction)dirstate_item_v2_data, METH_NOARGS,
				"return data suitable for v2 serialization"},
	{"v1_state", (PyCFunction)dirstate_item_v1_state, METH_NOARGS,			{"v1_state", (PyCFunction)dirstate_item_v1_state, METH_NOARGS,
	"return a \"state\" suitable for v1 serialization"},			"return a \"state\" suitable for v1 serialization"},
	{"v1_mode", (PyCFunction)dirstate_item_v1_mode, METH_NOARGS,			{"v1_mode", (PyCFunction)dirstate_item_v1_mode, METH_NOARGS,
	"return a \"mode\" suitable for v1 serialization"},			"return a \"mode\" suitable for v1 serialization"},
	{"v1_size", (PyCFunction)dirstate_item_v1_size, METH_NOARGS,			{"v1_size", (PyCFunction)dirstate_item_v1_size, METH_NOARGS,
	"return a \"size\" suitable for v1 serialization"},			"return a \"size\" suitable for v1 serialization"},
	{"v1_mtime", (PyCFunction)dirstate_item_v1_mtime, METH_NOARGS,			{"v1_mtime", (PyCFunction)dirstate_item_v1_mtime, METH_NOARGS,
	"return a \"mtime\" suitable for v1 serialization"},			"return a \"mtime\" suitable for v1 serialization"},

mercurial/dirstateutils/v2.py

	# v2.py - Pure-Python implementation of the dirstate-v2 file format			# v2.py - Pure-Python implementation of the dirstate-v2 file format
	#			#
	# Copyright Mercurial Contributors			# Copyright Mercurial Contributors
	#			#
	# This software may be used and distributed according to the terms of the			# This software may be used and distributed according to the terms of the
	# GNU General Public License version 2 or any later version.			# GNU General Public License version 2 or any later version.

	from __future__ import absolute_import			from __future__ import absolute_import

	import struct			import struct

	from .. import policy			from ..thirdparty import attr
				from .. import error, policy

	parsers = policy.importmod('parsers')			parsers = policy.importmod('parsers')


	# Must match the constant of the same name in			# Must match the constant of the same name in
	# `rust/hg-core/src/dirstate_tree/on_disk.rs`			# `rust/hg-core/src/dirstate_tree/on_disk.rs`
	TREE_METADATA_SIZE = 44			TREE_METADATA_SIZE = 44
	NODE_SIZE = 43			NODE_SIZE = 43
	This is used by parse_dirstate to recursively fill `map` and `copy_map`.			This is used by parse_dirstate to recursively fill `map` and `copy_map`.
	"""			"""
	for i in range(len):			for i in range(len):
	node_start = start + NODE_SIZE * i			node_start = start + NODE_SIZE * i
	node_bytes = slice_with_len(data, node_start, NODE_SIZE)			node_bytes = slice_with_len(data, node_start, NODE_SIZE)
	(			(
	path_start,			path_start,
	path_len,			path_len,
	_basename_start,			_basename_start,
				marmouteUnsubmitted Not Done This should go in the previous changesets. marmoute: This should go in the previous changesets.
	copy_source_start,			copy_source_start,
	copy_source_len,			copy_source_len,
	children_start,			children_start,
	children_count,			children_count,
	_descendants_with_entry_count,			_descendants_with_entry_count,
	_tracked_descendants_count,			_tracked_descendants_count,
	flags,			flags,
	mode,			mode,
	if copy_source_start:			if copy_source_start:
	copy_map[path] = slice_with_len(			copy_map[path] = slice_with_len(
	data, copy_source_start, copy_source_len			data, copy_source_start, copy_source_len
	)			)


	def slice_with_len(data, start, len):			def slice_with_len(data, start, len):
	return data[start : start + len]			return data[start : start + len]


				@attr.s
				class Node(object):
				path = attr.ib()
				entry = attr.ib()
				parent = attr.ib(default=None)
				children_count = attr.ib(default=0)
				children_offset = attr.ib(default=0)
				descendants_with_entry = attr.ib(default=0)
				tracked_descendants = attr.ib(default=0)

				def pack(self, copy_map, paths_offset):
				path = self.path
				copy = copy_map.get(path)
				entry = self.entry

				path_start = paths_offset
				path_len = len(path)
				basename_start = path.rfind(b'/') + 1 # 0 if rfind returns -1
				if copy is not None:
				copy_source_start = paths_offset + len(path)
				copy_source_len = len(copy)
				else:
				copy_source_start = 0
				copy_source_len = 0
				if entry is not None:
				flags, mode, size, mtime = entry.v2_data()
				else:
				# There are no mtime-cached directories in the Python implementation
				flags = 0
				mode = 0
				size = 0
				mtime = 0
				return NODE.pack(
				path_start,
				path_len,
				basename_start,
				copy_source_start,
				copy_source_len,
				self.children_offset,
				self.children_count,
				self.descendants_with_entry,
				self.tracked_descendants,
				flags,
				mode,
				size,
				mtime,
				)


				def pack_dirstate(map, copy_map, now):
				"""
				Pack `map` and `copy_map` into the dirstate v2 binary format and return
				the bytearray.
				`now` is a timestamp of the current filesystem time used to detect race
				conditions in writing the dirstate to disk, see inline comment.

				The on-disk format expects a tree-like structure where the leaves are
				written first (and sorted per-directory), going up levels until the root
				node and writing that one to the docket. See more details on the on-disk
				format in `mercurial/helptext/internals/dirstate-v2`.

				Since both `map` and `copy_map` are flat dicts we need to figure out the
				hierarchy. This algorithm does so without having to build the entire tree
				in-memory: it only keeps the minimum number of nodes around to satisfy the
				format.

				# Algorithm explanation

				This explanation does not talk about the different counters for tracked
				descendents and storing the copies, but that work is pretty simple once this
				algorithm is in place.

				## Building a subtree

				First, sort `map`: this makes it so the leaves of the tree are contiguous
				per directory (i.e. a/b/c and a/b/d will be next to each other in the list),
				and enables us to use the ordering of folders to have a "cursor" of the
				current folder we're in without ever going twice in the same branch of the
				tree. The cursor is a node that remembers its parent and any information
				relevant to the format (see the `Node` class), building the relevant part
				of the tree lazily.
				Then, for each file in `map`, move the cursor into the tree to the
				corresponding folder of the file: for example, if the very first file
				is "a/b/c", we start from `Node[""]`, create `Node["a"]` which points to
				its parent `Node[""]`, then create `Node["a/b"]`, which points to its parent
				`Node["a"]`. These nodes are kept around in a stack.
				If the next file in `map` is in the same subtree ("a/b/d" or "a/b/e/f"), we
				add it to the stack and keep looping with the same logic of creating the
				tree nodes as needed. If however the next file in `map` is not in the same
				subtree ("a/other", if we're still in the "a/b" folder), then we know that
				the subtree we're in is complete.

				## Writing the subtree

				We have the entire subtree in the stack, so we start writing it to disk
				folder by folder. The way we write a folder is to pop the stack into a list
				until the folder changes, revert this list of direct children (to satisfy
				the format requirement that children be sorted). This process repeats until
				we hit the "other" subtree.

				An example:
				a
				dir1/b
				dir1/c
				dir2/dir3/d
				dir2/dir3/e
				dir2/f

				Would have us:
				- add to the stack until "dir2/dir3/e"
				- realize that "dir2/f" is in a different subtree
				- pop "dir2/dir3/e", "dir2/dir3/d", reverse them so they're sorted and
				pack them since the next entry is "dir2/dir3"
				- go back up to "dir2"
				- add "dir2/f" to the stack
				- realize we're done with the map
				- pop "dir2/f", "dir2/dir3" from the stack, reverse and pack them
				- go up to the root node, do the same to write "a", "dir1" and "dir2" in
				that order

				## Special case for the root node

				The root node is not serialized in the format, but its information is
				written to the docket. Again, see more details on the on-disk format in
				`mercurial/helptext/internals/dirstate-v2`.
				"""
				now = int(now)
				data = bytearray()
				root_nodes_start = 0
				root_nodes_len = 0
				nodes_with_entry_count = 0
				nodes_with_copy_source_count = 0
				# Will always be 0 since this implementation always re-writes everything
				# to disk
				unreachable_bytes = 0
				unused = b'\x00' * 4
				# This is an optimization that's only useful for the Rust implementation
				ignore_patterns_hash = b'\x00' * 20

				if len(map) == 0:
				tree_metadata = TREE_METADATA.pack(
				root_nodes_start,
				root_nodes_len,
				nodes_with_entry_count,
				nodes_with_copy_source_count,
				unreachable_bytes,
				unused,
				ignore_patterns_hash,
				)
				return data, tree_metadata

				marmouteUnsubmitted Not Done This block should go in the `if len(map) ==0:` block marmoute: This block should go in the `if len(map) ==0:` block
				sorted_map = sorted(map.items(), key=lambda x: x[0])

				# Use a stack to not have to only remember the nodes we currently need
				# instead of building the entire tree in memory
				stack = []
				current_node = Node(b"", None)
				stack.append(current_node)

				for index, (path, entry) in enumerate(sorted_map, 1):
				if entry.need_delay(now):
				# The file was last modified "simultaneously" with the current
				# write to dirstate (i.e. within the same second for file-
				# systems with a granularity of 1 sec). This commonly happens
				# for at least a couple of files on 'update'.
				# The user could change the file without changing its size
				# within the same second. Invalidate the file's mtime in
				# dirstate, forcing future 'status' calls to compare the
				# contents of the file if the size is the same. This prevents
				# mistakenly treating such files as clean.
				entry.set_possibly_dirty()
				nodes_with_entry_count += 1
				if path in copy_map:
				nodes_with_copy_source_count += 1
				current_folder = get_folder(path)
				current_node = move_to_correct_node_in_tree(
				current_folder, current_node, stack
				)

				current_node.children_count += 1
				# Entries from `map` are never `None`
				if entry.tracked:
				current_node.tracked_descendants += 1
				current_node.descendants_with_entry += 1
				stack.append(Node(path, entry, current_node))
				marmouteUnsubmitted Not Done This probably deserve that we check `any_tracked`¹ here. [1] introduced in a parallel series marmoute: This probably deserve that we check `any_tracked`¹ here. [1] introduced in a parallel series

				should_pack = True
				next_path = None
				if index < len(sorted_map):
				# Determine if the next entry is in the same sub-tree, if so don't
				# pack yet
				next_path = sorted_map[index][0]
				should_pack = not get_folder(next_path).startswith(current_folder)
				marmouteUnsubmitted Not Done can probably be a `<` for clarity. marmoute: can probably be a `<` for clarity.
				if should_pack:
				pack_directory_children(current_node, copy_map, data, stack)
				while stack and current_node.path != b"":
				# Go up the tree and write until we reach the folder of the next
				# entry (if any, otherwise the root)
				parent = current_node.parent
				in_parent_folder_of_next_entry = next_path is not None and (
				get_folder(next_path).startswith(get_folder(stack[-1].path))
				)
				if parent is None or in_parent_folder_of_next_entry:
				break
				pack_directory_children(parent, copy_map, data, stack)
				current_node = parent

				# Special case for the root node since we don't write it to disk, only its
				# children to the docket
				current_node = stack.pop()
				assert current_node.path == b"", current_node.path
				assert len(stack) == 0, len(stack)

				tree_metadata = TREE_METADATA.pack(
				current_node.children_offset,
				current_node.children_count,
				nodes_with_entry_count,
				nodes_with_copy_source_count,
				unreachable_bytes,
				unused,
				ignore_patterns_hash,
				)

				return data, tree_metadata


				def get_folder(path):
				"""
				Return the folder of the path that's given, an empty string for root paths.
				"""
				return path.rsplit(b'/', 1)[0] if b'/' in path else b''


				def move_to_correct_node_in_tree(target_folder, current_node, stack):
				"""
				Move inside the dirstate node tree to the node corresponding to
				`target_folder`, creating the missing nodes along the way if needed.
				"""
				while target_folder != current_node.path:
				if target_folder.startswith(current_node.path):
				# We need to go down a folder
				prefix = target_folder[len(current_node.path) :].lstrip(b'/')
				subfolder_name = prefix.split(b'/', 1)[0]
				if current_node.path:
				subfolder_path = current_node.path + b'/' + subfolder_name
				else:
				subfolder_path = subfolder_name
				next_node = stack[-1]
				if next_node.path == target_folder:
				# This folder is now a file and only contains removed entries
				# merge with the last node
				current_node = next_node
				else:
				current_node.children_count += 1
				current_node = Node(subfolder_path, None, current_node)
				stack.append(current_node)
				else:
				# We need to go up a folder
				current_node = current_node.parent
				return current_node


				def pack_directory_children(node, copy_map, data, stack):
				"""
				Write the binary representation of the direct sorted children of `node` to
				`data`
				"""
				direct_children = []

				while stack[-1].path != b"" and get_folder(stack[-1].path) == node.path:
				direct_children.append(stack.pop())
				if not direct_children:
				raise error.ProgrammingError(b"no direct children for %r" % node.path)

				# Reverse the stack to get the correct sorted order
				direct_children.reverse()
				packed_children = bytearray()
				# Write the paths to `data`. Pack child nodes but don't write them yet
				for child in direct_children:
				packed = child.pack(copy_map=copy_map, paths_offset=len(data))
				packed_children.extend(packed)
				data.extend(child.path)
				data.extend(copy_map.get(child.path, b""))
				node.tracked_descendants += child.tracked_descendants
				node.descendants_with_entry += child.descendants_with_entry
				# Write the fixed-size child nodes all together
				node.children_offset = len(data)
				data.extend(packed_children)

mercurial/pure/parsers.py

	"""			"""
	return self._wc_tracked and self._p2_info			return self._wc_tracked and self._p2_info

	@property			@property
	def removed(self):			def removed(self):
	"""True if the file has been removed"""			"""True if the file has been removed"""
	return not self._wc_tracked and (self._p1_tracked or self._p2_info)			return not self._wc_tracked and (self._p1_tracked or self._p2_info)

				def v2_data(self):
				"""Returns (flags, mode, size, mtime) for v2 serialization"""
				flags = 0
				if self._wc_tracked:
				flags \|= DIRSTATE_V2_WDIR_TRACKED
				if self._p1_tracked:
				flags \|= DIRSTATE_V2_P1_TRACKED
				if self._p2_info:
				flags \|= DIRSTATE_V2_P2_INFO
				if self.mode is not None and self.size is not None:
				flags \|= DIRSTATE_V2_HAS_MODE_AND_SIZE
				if self.mtime is not None:
				flags \|= DIRSTATE_V2_HAS_MTIME
				return (flags, self.mode or 0, self.size or 0, self.mtime or 0)

	def v1_state(self):			def v1_state(self):
	"""return a "state" suitable for v1 serialization"""			"""return a "state" suitable for v1 serialization"""
	if not self.any_tracked:			if not self.any_tracked:
	# the object has no state to record, this is -currently-			# the object has no state to record, this is -currently-
	# unsupported			# unsupported
	raise RuntimeError('untracked item')			raise RuntimeError('untracked item')
	elif self.removed:			elif self.removed:
	return b'r'			return b'r'

			Path	Packages
M			mercurial/cext/parsers.c (8 lines)
M			mercurial/dirstateutils/v2.py (293 lines)
M			mercurial/pure/parsers.py (15 lines)

This is an archive of the discontinued Mercurial Phabricator instance.

dirstate-v2: Initial Python serializer
ClosedPublic

Details

Diff Detail

Event Timeline

Revision Contents
Changeset List

Diff 30760

mercurial/cext/parsers.c

mercurial/dirstateutils/v2.py

mercurial/pure/parsers.py

This is an archive of the discontinued Mercurial Phabricator instance.

dirstate-v2: Initial Python serializerClosedPublic

Details

Diff Detail

Event Timeline

Revision ContentsChangeset List

Diff 30760

mercurial/cext/parsers.c

mercurial/dirstateutils/v2.py

mercurial/pure/parsers.py

dirstate-v2: Initial Python serializer
ClosedPublic

Revision Contents
Changeset List