Merge commit 'c2b0355b0de23f6ec83b5fa5be038bcce208e26f' as 'waflib'

1 files changed, 970 insertions, 0 deletions

diff --git a/waflib/Node.py b/waflib/Node.py
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+++ b/waflib/Node.py
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+#!/usr/bin/env python
+# encoding: utf-8
+# Thomas Nagy, 2005-2018 (ita)
+
+"""
+Node: filesystem structure
+
+#. Each file/folder is represented by exactly one node.
+
+#. Some potential class properties are stored on :py:class:`waflib.Build.BuildContext` : nodes to depend on, etc.
+   Unused class members can increase the `.wafpickle` file size sensibly.
+
+#. Node objects should never be created directly, use
+   the methods :py:func:`Node.make_node` or :py:func:`Node.find_node` for the low-level operations
+
+#. The methods :py:func:`Node.find_resource`, :py:func:`Node.find_dir` :py:func:`Node.find_or_declare` must be
+   used when a build context is present
+
+#. Each instance of :py:class:`waflib.Context.Context` has a unique :py:class:`Node` subclass required for serialization.
+   (:py:class:`waflib.Node.Nod3`, see the :py:class:`waflib.Context.Context` initializer). A reference to the context
+   owning a node is held as *self.ctx*
+"""
+
+import os, re, sys, shutil
+from waflib import Utils, Errors
+
+exclude_regs = '''
+**/*~
+**/#*#
+**/.#*
+**/%*%
+**/._*
+**/*.swp
+**/CVS
+**/CVS/**
+**/.cvsignore
+**/SCCS
+**/SCCS/**
+**/vssver.scc
+**/.svn
+**/.svn/**
+**/BitKeeper
+**/.git
+**/.git/**
+**/.gitignore
+**/.bzr
+**/.bzrignore
+**/.bzr/**
+**/.hg
+**/.hg/**
+**/_MTN
+**/_MTN/**
+**/.arch-ids
+**/{arch}
+**/_darcs
+**/_darcs/**
+**/.intlcache
+**/.DS_Store'''
+"""
+Ant patterns for files and folders to exclude while doing the
+recursive traversal in :py:meth:`waflib.Node.Node.ant_glob`
+"""
+
+def ant_matcher(s, ignorecase):
+	reflags = re.I if ignorecase else 0
+	ret = []
+	for x in Utils.to_list(s):
+		x = x.replace('\\', '/').replace('//', '/')
+		if x.endswith('/'):
+			x += '**'
+		accu = []
+		for k in x.split('/'):
+			if k == '**':
+				accu.append(k)
+			else:
+				k = k.replace('.', '[.]').replace('*','.*').replace('?', '.').replace('+', '\\+')
+				k = '^%s$' % k
+				try:
+					exp = re.compile(k, flags=reflags)
+				except Exception as e:
+					raise Errors.WafError('Invalid pattern: %s' % k, e)
+				else:
+					accu.append(exp)
+		ret.append(accu)
+	return ret
+
+def ant_sub_filter(name, nn):
+	ret = []
+	for lst in nn:
+		if not lst:
+			pass
+		elif lst[0] == '**':
+			ret.append(lst)
+			if len(lst) > 1:
+				if lst[1].match(name):
+					ret.append(lst[2:])
+			else:
+				ret.append([])
+		elif lst[0].match(name):
+			ret.append(lst[1:])
+	return ret
+
+def ant_sub_matcher(name, pats):
+	nacc = ant_sub_filter(name, pats[0])
+	nrej = ant_sub_filter(name, pats[1])
+	if [] in nrej:
+		nacc = []
+	return [nacc, nrej]
+
+class Node(object):
+	"""
+	This class is organized in two parts:
+
+	* The basic methods meant for filesystem access (compute paths, create folders, etc)
+	* The methods bound to a :py:class:`waflib.Build.BuildContext` (require ``bld.srcnode`` and ``bld.bldnode``)
+	"""
+
+	dict_class = dict
+	"""
+	Subclasses can provide a dict class to enable case insensitivity for example.
+	"""
+
+	__slots__ = ('name', 'parent', 'children', 'cache_abspath', 'cache_isdir')
+	def __init__(self, name, parent):
+		"""
+		.. note:: Use :py:func:`Node.make_node` or :py:func:`Node.find_node` instead of calling this constructor
+		"""
+		self.name = name
+		self.parent = parent
+		if parent:
+			if name in parent.children:
+				raise Errors.WafError('node %s exists in the parent files %r already' % (name, parent))
+			parent.children[name] = self
+
+	def __setstate__(self, data):
+		"Deserializes node information, used for persistence"
+		self.name = data[0]
+		self.parent = data[1]
+		if data[2] is not None:
+			# Issue 1480
+			self.children = self.dict_class(data[2])
+
+	def __getstate__(self):
+		"Serializes node information, used for persistence"
+		return (self.name, self.parent, getattr(self, 'children', None))
+
+	def __str__(self):
+		"""
+		String representation (abspath), for debugging purposes
+
+		:rtype: string
+		"""
+		return self.abspath()
+
+	def __repr__(self):
+		"""
+		String representation (abspath), for debugging purposes
+
+		:rtype: string
+		"""
+		return self.abspath()
+
+	def __copy__(self):
+		"""
+		Provided to prevent nodes from being copied
+
+		:raises: :py:class:`waflib.Errors.WafError`
+		"""
+		raise Errors.WafError('nodes are not supposed to be copied')
+
+	def read(self, flags='r', encoding='latin-1'):
+		"""
+		Reads and returns the contents of the file represented by this node, see :py:func:`waflib.Utils.readf`::
+
+			def build(bld):
+				bld.path.find_node('wscript').read()
+
+		:param flags: Open mode
+		:type  flags: string
+		:param encoding: encoding value for Python3
+		:type encoding: string
+		:rtype: string or bytes
+		:return: File contents
+		"""
+		return Utils.readf(self.abspath(), flags, encoding)
+
+	def write(self, data, flags='w', encoding='latin-1'):
+		"""
+		Writes data to the file represented by this node, see :py:func:`waflib.Utils.writef`::
+
+			def build(bld):
+				bld.path.make_node('foo.txt').write('Hello, world!')
+
+		:param data: data to write
+		:type  data: string
+		:param flags: Write mode
+		:type  flags: string
+		:param encoding: encoding value for Python3
+		:type encoding: string
+		"""
+		Utils.writef(self.abspath(), data, flags, encoding)
+
+	def read_json(self, convert=True, encoding='utf-8'):
+		"""
+		Reads and parses the contents of this node as JSON (Python ≥ 2.6)::
+
+			def build(bld):
+				bld.path.find_node('abc.json').read_json()
+
+		Note that this by default automatically decodes unicode strings on Python2, unlike what the Python JSON module does.
+
+		:type  convert: boolean
+		:param convert: Prevents decoding of unicode strings on Python2
+		:type  encoding: string
+		:param encoding: The encoding of the file to read. This default to UTF8 as per the JSON standard
+		:rtype: object
+		:return: Parsed file contents
+		"""
+		import json # Python 2.6 and up
+		object_pairs_hook = None
+		if convert and sys.hexversion < 0x3000000:
+			try:
+				_type = unicode
+			except NameError:
+				_type = str
+
+			def convert(value):
+				if isinstance(value, list):
+					return [convert(element) for element in value]
+				elif isinstance(value, _type):
+					return str(value)
+				else:
+					return value
+
+			def object_pairs(pairs):
+				return dict((str(pair[0]), convert(pair[1])) for pair in pairs)
+
+			object_pairs_hook = object_pairs
+
+		return json.loads(self.read(encoding=encoding), object_pairs_hook=object_pairs_hook)
+
+	def write_json(self, data, pretty=True):
+		"""
+		Writes a python object as JSON to disk (Python ≥ 2.6) as UTF-8 data (JSON standard)::
+
+			def build(bld):
+				bld.path.find_node('xyz.json').write_json(199)
+
+		:type  data: object
+		:param data: The data to write to disk
+		:type  pretty: boolean
+		:param pretty: Determines if the JSON will be nicely space separated
+		"""
+		import json # Python 2.6 and up
+		indent = 2
+		separators = (',', ': ')
+		sort_keys = pretty
+		newline = os.linesep
+		if not pretty:
+			indent = None
+			separators = (',', ':')
+			newline = ''
+		output = json.dumps(data, indent=indent, separators=separators, sort_keys=sort_keys) + newline
+		self.write(output, encoding='utf-8')
+
+	def exists(self):
+		"""
+		Returns whether the Node is present on the filesystem
+
+		:rtype: bool
+		"""
+		return os.path.exists(self.abspath())
+
+	def isdir(self):
+		"""
+		Returns whether the Node represents a folder
+
+		:rtype: bool
+		"""
+		return os.path.isdir(self.abspath())
+
+	def chmod(self, val):
+		"""
+		Changes the file/dir permissions::
+
+			def build(bld):
+				bld.path.chmod(493) # 0755
+		"""
+		os.chmod(self.abspath(), val)
+
+	def delete(self, evict=True):
+		"""
+		Removes the file/folder from the filesystem (equivalent to `rm -rf`), and remove this object from the Node tree.
+		Do not use this object after calling this method.
+		"""
+		try:
+			try:
+				if os.path.isdir(self.abspath()):
+					shutil.rmtree(self.abspath())
+				else:
+					os.remove(self.abspath())
+			except OSError:
+				if os.path.exists(self.abspath()):
+					raise
+		finally:
+			if evict:
+				self.evict()
+
+	def evict(self):
+		"""
+		Removes this node from the Node tree
+		"""
+		del self.parent.children[self.name]
+
+	def suffix(self):
+		"""
+		Returns the file rightmost extension, for example `a.b.c.d → .d`
+
+		:rtype: string
+		"""
+		k = max(0, self.name.rfind('.'))
+		return self.name[k:]
+
+	def height(self):
+		"""
+		Returns the depth in the folder hierarchy from the filesystem root or from all the file drives
+
+		:returns: filesystem depth
+		:rtype: integer
+		"""
+		d = self
+		val = -1
+		while d:
+			d = d.parent
+			val += 1
+		return val
+
+	def listdir(self):
+		"""
+		Lists the folder contents
+
+		:returns: list of file/folder names ordered alphabetically
+		:rtype: list of string
+		"""
+		lst = Utils.listdir(self.abspath())
+		lst.sort()
+		return lst
+
+	def mkdir(self):
+		"""
+		Creates a folder represented by this node. Intermediate folders are created as needed.
+
+		:raises: :py:class:`waflib.Errors.WafError` when the folder is missing
+		"""
+		if self.isdir():
+			return
+
+		try:
+			self.parent.mkdir()
+		except OSError:
+			pass
+
+		if self.name:
+			try:
+				os.makedirs(self.abspath())
+			except OSError:
+				pass
+
+			if not self.isdir():
+				raise Errors.WafError('Could not create the directory %r' % self)
+
+			try:
+				self.children
+			except AttributeError:
+				self.children = self.dict_class()
+
+	def find_node(self, lst):
+		"""
+		Finds a node on the file system (files or folders), and creates the corresponding Node objects if it exists
+
+		:param lst: relative path
+		:type lst: string or list of string
+		:returns: The corresponding Node object or None if no entry was found on the filesystem
+		:rtype: :py:class:´waflib.Node.Node´
+		"""
+
+		if isinstance(lst, str):
+			lst = [x for x in Utils.split_path(lst) if x and x != '.']
+
+		if lst and lst[0].startswith('\\\\') and not self.parent:
+			node = self.ctx.root.make_node(lst[0])
+			node.cache_isdir = True
+			return node.find_node(lst[1:])
+
+		cur = self
+		for x in lst:
+			if x == '..':
+				cur = cur.parent or cur
+				continue
+
+			try:
+				ch = cur.children
+			except AttributeError:
+				cur.children = self.dict_class()
+			else:
+				try:
+					cur = ch[x]
+					continue
+				except KeyError:
+					pass
+
+			# optimistic: create the node first then look if it was correct to do so
+			cur = self.__class__(x, cur)
+			if not cur.exists():
+				cur.evict()
+				return None
+
+		if not cur.exists():
+			cur.evict()
+			return None
+
+		return cur
+
+	def make_node(self, lst):
+		"""
+		Returns or creates a Node object corresponding to the input path without considering the filesystem.
+
+		:param lst: relative path
+		:type lst: string or list of string
+		:rtype: :py:class:´waflib.Node.Node´
+		"""
+		if isinstance(lst, str):
+			lst = [x for x in Utils.split_path(lst) if x and x != '.']
+
+		cur = self
+		for x in lst:
+			if x == '..':
+				cur = cur.parent or cur
+				continue
+
+			try:
+				cur = cur.children[x]
+			except AttributeError:
+				cur.children = self.dict_class()
+			except KeyError:
+				pass
+			else:
+				continue
+			cur = self.__class__(x, cur)
+		return cur
+
+	def search_node(self, lst):
+		"""
+		Returns a Node previously defined in the data structure. The filesystem is not considered.
+
+		:param lst: relative path
+		:type lst: string or list of string
+		:rtype: :py:class:´waflib.Node.Node´ or None if there is no entry in the Node datastructure
+		"""
+		if isinstance(lst, str):
+			lst = [x for x in Utils.split_path(lst) if x and x != '.']
+
+		cur = self
+		for x in lst:
+			if x == '..':
+				cur = cur.parent or cur
+			else:
+				try:
+					cur = cur.children[x]
+				except (AttributeError, KeyError):
+					return None
+		return cur
+
+	def path_from(self, node):
+		"""
+		Path of this node seen from the other::
+
+			def build(bld):
+				n1 = bld.path.find_node('foo/bar/xyz.txt')
+				n2 = bld.path.find_node('foo/stuff/')
+				n1.path_from(n2) # '../bar/xyz.txt'
+
+		:param node: path to use as a reference
+		:type node: :py:class:`waflib.Node.Node`
+		:returns: a relative path or an absolute one if that is better
+		:rtype: string
+		"""
+		c1 = self
+		c2 = node
+
+		c1h = c1.height()
+		c2h = c2.height()
+
+		lst = []
+		up = 0
+
+		while c1h > c2h:
+			lst.append(c1.name)
+			c1 = c1.parent
+			c1h -= 1
+
+		while c2h > c1h:
+			up += 1
+			c2 = c2.parent
+			c2h -= 1
+
+		while not c1 is c2:
+			lst.append(c1.name)
+			up += 1
+
+			c1 = c1.parent
+			c2 = c2.parent
+
+		if c1.parent:
+			lst.extend(['..'] * up)
+			lst.reverse()
+			return os.sep.join(lst) or '.'
+		else:
+			return self.abspath()
+
+	def abspath(self):
+		"""
+		Returns the absolute path. A cache is kept in the context as ``cache_node_abspath``
+
+		:rtype: string
+		"""
+		try:
+			return self.cache_abspath
+		except AttributeError:
+			pass
+		# think twice before touching this (performance + complexity + correctness)
+
+		if not self.parent:
+			val = os.sep
+		elif not self.parent.name:
+			val = os.sep + self.name
+		else:
+			val = self.parent.abspath() + os.sep + self.name
+		self.cache_abspath = val
+		return val
+
+	if Utils.is_win32:
+		def abspath(self):
+			try:
+				return self.cache_abspath
+			except AttributeError:
+				pass
+			if not self.parent:
+				val = ''
+			elif not self.parent.name:
+				val = self.name + os.sep
+			else:
+				val = self.parent.abspath().rstrip(os.sep) + os.sep + self.name
+			self.cache_abspath = val
+			return val
+
+	def is_child_of(self, node):
+		"""
+		Returns whether the object belongs to a subtree of the input node::
+
+			def build(bld):
+				node = bld.path.find_node('wscript')
+				node.is_child_of(bld.path) # True
+
+		:param node: path to use as a reference
+		:type node: :py:class:`waflib.Node.Node`
+		:rtype: bool
+		"""
+		p = self
+		diff = self.height() - node.height()
+		while diff > 0:
+			diff -= 1
+			p = p.parent
+		return p is node
+
+	def ant_iter(self, accept=None, maxdepth=25, pats=[], dir=False, src=True, remove=True, quiet=False):
+		"""
+		Recursive method used by :py:meth:`waflib.Node.ant_glob`.
+
+		:param accept: function used for accepting/rejecting a node, returns the patterns that can be still accepted in recursion
+		:type accept: function
+		:param maxdepth: maximum depth in the filesystem (25)
+		:type maxdepth: int
+		:param pats: list of patterns to accept and list of patterns to exclude
+		:type pats: tuple
+		:param dir: return folders too (False by default)
+		:type dir: bool
+		:param src: return files (True by default)
+		:type src: bool
+		:param remove: remove files/folders that do not exist (True by default)
+		:type remove: bool
+		:param quiet: disable build directory traversal warnings (verbose mode)
+		:type quiet: bool
+		:returns: A generator object to iterate from
+		:rtype: iterator
+		"""
+		dircont = self.listdir()
+		dircont.sort()
+
+		try:
+			lst = set(self.children.keys())
+		except AttributeError:
+			self.children = self.dict_class()
+		else:
+			if remove:
+				for x in lst - set(dircont):
+					self.children[x].evict()
+
+		for name in dircont:
+			npats = accept(name, pats)
+			if npats and npats[0]:
+				accepted = [] in npats[0]
+
+				node = self.make_node([name])
+
+				isdir = node.isdir()
+				if accepted:
+					if isdir:
+						if dir:
+							yield node
+					elif src:
+						yield node
+
+				if isdir:
+					node.cache_isdir = True
+					if maxdepth:
+						for k in node.ant_iter(accept=accept, maxdepth=maxdepth - 1, pats=npats, dir=dir, src=src, remove=remove, quiet=quiet):
+							yield k
+
+	def ant_glob(self, *k, **kw):
+		"""
+		Finds files across folders and returns Node objects:
+
+		* ``**/*`` find all files recursively
+		* ``**/*.class`` find all files ending by .class
+		* ``..`` find files having two dot characters
+
+		For example::
+
+			def configure(cfg):
+				# find all .cpp files
+				cfg.path.ant_glob('**/*.cpp')
+				# find particular files from the root filesystem (can be slow)
+				cfg.root.ant_glob('etc/*.txt')
+				# simple exclusion rule example
+				cfg.path.ant_glob('*.c*', excl=['*.c'], src=True, dir=False)
+
+		For more information about the patterns, consult http://ant.apache.org/manual/dirtasks.html
+		Please remember that the '..' sequence does not represent the parent directory::
+
+			def configure(cfg):
+				cfg.path.ant_glob('../*.h') # incorrect
+				cfg.path.parent.ant_glob('*.h') # correct
+
+		The Node structure is itself a filesystem cache, so certain precautions must
+		be taken while matching files in the build or installation phases.
+		Nodes objects that do have a corresponding file or folder are garbage-collected by default.
+		This garbage collection is usually required to prevent returning files that do not
+		exist anymore. Yet, this may also remove Node objects of files that are yet-to-be built.
+
+		This typically happens when trying to match files in the build directory,
+		but there are also cases when files are created in the source directory.
+		Run ``waf -v`` to display any warnings, and try consider passing ``remove=False``
+		when matching files in the build directory.
+
+		Since ant_glob can traverse both source and build folders, it is a best practice
+		to call this method only from the most specific build node::
+
+			def build(bld):
+				# traverses the build directory, may need ``remove=False``:
+				bld.path.ant_glob('project/dir/**/*.h')
+				# better, no accidental build directory traversal:
+				bld.path.find_node('project/dir').ant_glob('**/*.h') # best
+
+		In addition, files and folders are listed immediately. When matching files in the
+		build folders, consider passing ``generator=True`` so that the generator object
+		returned can defer computation to a later stage. For example::
+
+			def build(bld):
+				bld(rule='tar xvf ${SRC}', source='arch.tar')
+				bld.add_group()
+				gen = bld.bldnode.ant_glob("*.h", generator=True, remove=True)
+				# files will be listed only after the arch.tar is unpacked
+				bld(rule='ls ${SRC}', source=gen, name='XYZ')
+
+
+		:param incl: ant patterns or list of patterns to include
+		:type incl: string or list of strings
+		:param excl: ant patterns or list of patterns to exclude
+		:type excl: string or list of strings
+		:param dir: return folders too (False by default)
+		:type dir: bool
+		:param src: return files (True by default)
+		:type src: bool
+		:param maxdepth: maximum depth of recursion
+		:type maxdepth: int
+		:param ignorecase: ignore case while matching (False by default)
+		:type ignorecase: bool
+		:param generator: Whether to evaluate the Nodes lazily
+		:type generator: bool
+		:param remove: remove files/folders that do not exist (True by default)
+		:type remove: bool
+		:param quiet: disable build directory traversal warnings (verbose mode)
+		:type quiet: bool
+		:returns: The corresponding Node objects as a list or as a generator object (generator=True)
+		:rtype: by default, list of :py:class:`waflib.Node.Node` instances
+		"""
+		src = kw.get('src', True)
+		dir = kw.get('dir')
+		excl = kw.get('excl', exclude_regs)
+		incl = k and k[0] or kw.get('incl', '**')
+		remove = kw.get('remove', True)
+		maxdepth = kw.get('maxdepth', 25)
+		ignorecase = kw.get('ignorecase', False)
+		quiet = kw.get('quiet', False)
+		pats = (ant_matcher(incl, ignorecase), ant_matcher(excl, ignorecase))
+
+		if kw.get('generator'):
+			return Utils.lazy_generator(self.ant_iter, (ant_sub_matcher, maxdepth, pats, dir, src, remove, quiet))
+
+		it = self.ant_iter(ant_sub_matcher, maxdepth, pats, dir, src, remove, quiet)
+		if kw.get('flat'):
+			# returns relative paths as a space-delimited string
+			# prefer Node objects whenever possible
+			return ' '.join(x.path_from(self) for x in it)
+		return list(it)
+
+	# ----------------------------------------------------------------------------
+	# the methods below require the source/build folders (bld.srcnode/bld.bldnode)
+
+	def is_src(self):
+		"""
+		Returns True if the node is below the source directory. Note that ``!is_src() ≠ is_bld()``
+
+		:rtype: bool
+		"""
+		cur = self
+		x = self.ctx.srcnode
+		y = self.ctx.bldnode
+		while cur.parent:
+			if cur is y:
+				return False
+			if cur is x:
+				return True
+			cur = cur.parent
+		return False
+
+	def is_bld(self):
+		"""
+		Returns True if the node is below the build directory. Note that ``!is_bld() ≠ is_src()``
+
+		:rtype: bool
+		"""
+		cur = self
+		y = self.ctx.bldnode
+		while cur.parent:
+			if cur is y:
+				return True
+			cur = cur.parent
+		return False
+
+	def get_src(self):
+		"""
+		Returns the corresponding Node object in the source directory (or self if already
+		under the source directory). Use this method only if the purpose is to create
+		a Node object (this is common with folders but not with files, see ticket 1937)
+
+		:rtype: :py:class:`waflib.Node.Node`
+		"""
+		cur = self
+		x = self.ctx.srcnode
+		y = self.ctx.bldnode
+		lst = []
+		while cur.parent:
+			if cur is y:
+				lst.reverse()
+				return x.make_node(lst)
+			if cur is x:
+				return self
+			lst.append(cur.name)
+			cur = cur.parent
+		return self
+
+	def get_bld(self):
+		"""
+		Return the corresponding Node object in the build directory (or self if already
+		under the build directory). Use this method only if the purpose is to create
+		a Node object (this is common with folders but not with files, see ticket 1937)
+
+		:rtype: :py:class:`waflib.Node.Node`
+		"""
+		cur = self
+		x = self.ctx.srcnode
+		y = self.ctx.bldnode
+		lst = []
+		while cur.parent:
+			if cur is y:
+				return self
+			if cur is x:
+				lst.reverse()
+				return self.ctx.bldnode.make_node(lst)
+			lst.append(cur.name)
+			cur = cur.parent
+		# the file is external to the current project, make a fake root in the current build directory
+		lst.reverse()
+		if lst and Utils.is_win32 and len(lst[0]) == 2 and lst[0].endswith(':'):
+			lst[0] = lst[0][0]
+		return self.ctx.bldnode.make_node(['__root__'] + lst)
+
+	def find_resource(self, lst):
+		"""
+		Use this method in the build phase to find source files corresponding to the relative path given.
+
+		First it looks up the Node data structure to find any declared Node object in the build directory.
+		If None is found, it then considers the filesystem in the source directory.
+
+		:param lst: relative path
+		:type lst: string or list of string
+		:returns: the corresponding Node object or None
+		:rtype: :py:class:`waflib.Node.Node`
+		"""
+		if isinstance(lst, str):
+			lst = [x for x in Utils.split_path(lst) if x and x != '.']
+
+		node = self.get_bld().search_node(lst)
+		if not node:
+			node = self.get_src().find_node(lst)
+		if node and node.isdir():
+			return None
+		return node
+
+	def find_or_declare(self, lst):
+		"""
+		Use this method in the build phase to declare output files which
+		are meant to be written in the build directory.
+
+		This method creates the Node object and its parent folder
+		as needed.
+
+		:param lst: relative path
+		:type lst: string or list of string
+		"""
+		if isinstance(lst, str) and os.path.isabs(lst):
+			node = self.ctx.root.make_node(lst)
+		else:
+			node = self.get_bld().make_node(lst)
+		node.parent.mkdir()
+		return node
+
+	def find_dir(self, lst):
+		"""
+		Searches for a folder on the filesystem (see :py:meth:`waflib.Node.Node.find_node`)
+
+		:param lst: relative path
+		:type lst: string or list of string
+		:returns: The corresponding Node object or None if there is no such folder
+		:rtype: :py:class:`waflib.Node.Node`
+		"""
+		if isinstance(lst, str):
+			lst = [x for x in Utils.split_path(lst) if x and x != '.']
+
+		node = self.find_node(lst)
+		if node and not node.isdir():
+			return None
+		return node
+
+	# helpers for building things
+	def change_ext(self, ext, ext_in=None):
+		"""
+		Declares a build node with a distinct extension; this is uses :py:meth:`waflib.Node.Node.find_or_declare`
+
+		:return: A build node of the same path, but with a different extension
+		:rtype: :py:class:`waflib.Node.Node`
+		"""
+		name = self.name
+		if ext_in is None:
+			k = name.rfind('.')
+			if k >= 0:
+				name = name[:k] + ext
+			else:
+				name = name + ext
+		else:
+			name = name[:- len(ext_in)] + ext
+
+		return self.parent.find_or_declare([name])
+
+	def bldpath(self):
+		"""
+		Returns the relative path seen from the build directory ``src/foo.cpp``
+
+		:rtype: string
+		"""
+		return self.path_from(self.ctx.bldnode)
+
+	def srcpath(self):
+		"""
+		Returns the relative path seen from the source directory ``../src/foo.cpp``
+
+		:rtype: string
+		"""
+		return self.path_from(self.ctx.srcnode)
+
+	def relpath(self):
+		"""
+		If a file in the build directory, returns :py:meth:`waflib.Node.Node.bldpath`,
+		else returns :py:meth:`waflib.Node.Node.srcpath`
+
+		:rtype: string
+		"""
+		cur = self
+		x = self.ctx.bldnode
+		while cur.parent:
+			if cur is x:
+				return self.bldpath()
+			cur = cur.parent
+		return self.srcpath()
+
+	def bld_dir(self):
+		"""
+		Equivalent to self.parent.bldpath()
+
+		:rtype: string
+		"""
+		return self.parent.bldpath()
+
+	def h_file(self):
+		"""
+		See :py:func:`waflib.Utils.h_file`
+
+		:return: a hash representing the file contents
+		:rtype: string or bytes
+		"""
+		return Utils.h_file(self.abspath())
+
+	def get_bld_sig(self):
+		"""
+		Returns a signature (see :py:meth:`waflib.Node.Node.h_file`) for the purpose
+		of build dependency calculation. This method uses a per-context cache.
+
+		:return: a hash representing the object contents
+		:rtype: string or bytes
+		"""
+		# previous behaviour can be set by returning self.ctx.node_sigs[self] when a build node
+		try:
+			cache = self.ctx.cache_sig
+		except AttributeError:
+			cache = self.ctx.cache_sig = {}
+		try:
+			ret = cache[self]
+		except KeyError:
+			p = self.abspath()
+			try:
+				ret = cache[self] = self.h_file()
+			except EnvironmentError:
+				if self.isdir():
+					# allow folders as build nodes, do not use the creation time
+					st = os.stat(p)
+					ret = cache[self] = Utils.h_list([p, st.st_ino, st.st_mode])
+					return ret
+				raise
+		return ret
+
+pickle_lock = Utils.threading.Lock()
+"""Lock mandatory for thread-safe node serialization"""
+
+class Nod3(Node):
+	"""Mandatory subclass for thread-safe node serialization"""
+	pass # do not remove
+
+