Source code for SCons.Scanner

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"""The Scanner package for the SCons software construction utility."""

import re

import SCons.Node.FS
import SCons.PathList
import SCons.Util

[docs]class _Null: pass
# This is used instead of None as a default argument value so None can be # used as an actual argument value. _null = _Null
[docs]def Scanner(function, *args, **kwargs): """Factory function to create a Scanner Object. Creates the appropriate Scanner based on the type of "function". TODO: Deprecate this some day. We've moved the functionality inside the ScannerBase class and really don't need this factory function any more. It was, however, used by some of our Tool modules, so the call probably ended up in various people's custom modules patterned on SCons code. """ if SCons.Util.is_Dict(function): return Selector(function, *args, **kwargs) return ScannerBase(function, *args, **kwargs)
[docs]class FindPathDirs: """Class to bind a specific E{*}PATH variable name to a function that will return all of the E{*}path directories. """ def __init__(self, variable) -> None: self.variable = variable def __call__(self, env, dir=None, target=None, source=None, argument=None): try: path = env[self.variable] except KeyError: return () dir = dir or env.fs._cwd path = SCons.PathList.PathList(path).subst_path(env, target, source) return tuple(dir.Rfindalldirs(path))
[docs]class ScannerBase: """Base class for dependency scanners. Implements straightforward, single-pass scanning of a single file. A Scanner is usually set up with a scanner function (and optionally a path function), but can also be a kind of dispatcher which passes control to other Scanners. A scanner function takes three arguments: a Node to scan for dependecies, the construction environment to use, and an optional tuple of paths (as generated by the optional path function). It must return a list containing the Nodes for all the direct dependencies of the file. The optional path function is called to return paths that can be searched for implicit dependency files. It takes five arguments: a construction environment, a Node for the directory containing the SConscript file that defined the primary target, a list of target nodes, a list of source nodes, and the optional argument for this instance. Examples:: s = Scanner(my_scanner_function) s = Scanner(function=my_scanner_function) s = Scanner(function=my_scanner_function, argument='foo') Args: function: either a scanner function taking two or three arguments and returning a list of File Nodes; or a mapping of keys to other Scanner objects. name: an optional name for identifying this scanner object (defaults to "NONE"). argument: an optional argument that will be passed to both *function* and *path_function*. skeys: an optional list argument that can be used to determine if this scanner can be used for a given Node. In the case of File nodes, for example, the *skeys* would be file suffixes. path_function: an optional function which returns a tuple of the directories that can be searched for implicit dependency files. May also return a callable which is called with no args and returns the tuple (supporting Bindable class). node_class: optional class of Nodes which this scan will return. If not specified, defaults to :class:`SCons.Node.FS.Base`. If *node_class* is ``None``, then this scanner will not enforce any Node conversion and will return the raw results from *function*. node_factory: optional factory function to be called to translate the raw results returned by *function* into the expected *node_class* objects. scan_check: optional function to be called to first check whether this node really needs to be scanned. recursive: optional specifier of whether this scanner should be invoked recursively on all of the implicit dependencies it returns (for example `#include` lines in C source files, which may refer to header files which should themselves be scanned). May be a callable, which will be called to filter the list of nodes found to select a subset for recursive scanning (the canonical example being only recursively scanning subdirectories within a directory). The default is to not do recursive scanning. """ def __init__( self, function, name: str="NONE", argument=_null, skeys=_null, path_function=None, # Node.FS.Base so that, by default, it's okay for a # scanner to return a Dir, File or Entry. node_class=SCons.Node.FS.Base, node_factory=None, scan_check=None, recursive=None, ) -> None: """Construct a new scanner object given a scanner function.""" # Note: this class could easily work with scanner functions that take # something other than a filename as an argument (e.g. a database # node) and a dependencies list that aren't file names. All that # would need to be changed is the documentation. self.function = function self.path_function = path_function = name self.argument = argument if skeys is _null: if SCons.Util.is_Dict(function): skeys = list(function.keys()) else: skeys = [] self.skeys = skeys self.node_class = node_class self.node_factory = node_factory self.scan_check = scan_check if callable(recursive): self.recurse_nodes = recursive elif recursive: self.recurse_nodes = self._recurse_all_nodes else: self.recurse_nodes = self._recurse_no_nodes
[docs] def path(self, env, dir=None, target=None, source=None): if not self.path_function: return () if self.argument is not _null: return self.path_function(env, dir, target, source, self.argument) return self.path_function(env, dir, target, source)
[docs] def __call__(self, node, env, path=()) -> list: """Scans a single object. Args: node: the node that will be passed to the scanner function env: the environment that will be passed to the scanner function. path: tuple of paths from the `path_function` Returns: A list of direct dependency nodes for the specified node. """ if self.scan_check and not self.scan_check(node, env): return [] # here we may morph into a different Scanner instance: self = # pylint: disable=self-cls-assignment if self.argument is not _null: node_list = self.function(node, env, path, self.argument) else: node_list = self.function(node, env, path) kw = {} if hasattr(node, 'dir'): kw['directory'] = node.dir conv = env.get_factory(self.node_factory) cls = self.node_class nl = [conv(n, **kw) if cls and not isinstance(n, cls) else n for n in node_list] return nl
def __eq__(self, other): try: return self.__dict__ == other.__dict__ except AttributeError: # other probably doesn't have a __dict__ return self.__dict__ == other def __hash__(self): return id(self) def __str__(self) -> str: return
[docs] def add_skey(self, skey) -> None: """Add a skey to the list of skeys""" self.skeys.append(skey)
[docs] def get_skeys(self, env=None): if env and SCons.Util.is_String(self.skeys): return env.subst_list(self.skeys)[0] return self.skeys
[docs] def select(self, node): if SCons.Util.is_Dict(self.function): key = node.scanner_key() try: return self.function[key] except KeyError: return None else: return self
[docs] @staticmethod def _recurse_all_nodes(nodes): return nodes
[docs] @staticmethod def _recurse_no_nodes(nodes): return []
# recurse_nodes = _recurse_no_nodes
[docs] def add_scanner(self, skey, scanner) -> None: self.function[skey] = scanner self.add_skey(skey)
# keep the old name for a while in case external users are using. # there are no more internal uses of this class by the name "Base" Base = ScannerBase
[docs]class Selector(ScannerBase): """ A class for selecting a more specific scanner based on the :func:`scanner_key` (suffix) for a specific Node. TODO: This functionality has been moved into the inner workings of the ScannerBase class, and this class will be deprecated at some point. (It was never exposed directly as part of the public interface, although it is used by the :func:`Scanner` factory function that was used by various Tool modules and therefore was likely a template for custom modules that may be out there.) """ def __init__(self, mapping, *args, **kwargs) -> None: super().__init__(None, *args, **kwargs) self.mapping = mapping self.skeys = list(mapping.keys()) def __call__(self, node, env, path=()): return, env, path)
[docs] def select(self, node): try: return self.mapping[node.scanner_key()] except KeyError: return None
[docs] def add_scanner(self, skey, scanner) -> None: self.mapping[skey] = scanner self.add_skey(skey)
[docs]class Current(ScannerBase): """ A class for scanning files that are source files (have no builder) or are derived files and are current (which implies that they exist, either locally or in a repository). """ def __init__(self, *args, **kwargs) -> None: def current_check(node, env): return not node.has_builder() or node.is_up_to_date() kwargs['scan_check'] = current_check super().__init__(*args, **kwargs)
[docs]class Classic(Current): """ A Scanner subclass to contain the common logic for classic CPP-style include scanning, but which can be customized to use different regular expressions to find the includes. Note that in order for this to work "out of the box" (without overriding the :meth:`find_include` and :meth:`sort_key1` methods), the regular expression passed to the constructor must return the name of the include file in group 0. """ def __init__(self, name, suffixes, path_variable, regex, *args, **kwargs) -> None: self.cre = re.compile(regex, re.M) def _scan(node, _, path=(), self=self): node = node.rfile() if not node.exists(): return [] return self.scan(node, path) kwargs['function'] = _scan kwargs['path_function'] = FindPathDirs(path_variable) # Allow recursive to propagate if child class specifies. # In this case resource scanner needs to specify a filter on which files # get recursively processed. Previously was hardcoded to 1 instead of # defaulted to 1. kwargs['recursive'] = kwargs.get('recursive', True) kwargs['skeys'] = suffixes kwargs['name'] = name super().__init__(*args, **kwargs)
[docs] @staticmethod def find_include(include, source_dir, path): n = SCons.Node.FS.find_file(include, (source_dir,) + tuple(path)) return n, include
[docs] @staticmethod def sort_key(include): return SCons.Node.FS._my_normcase(include)
[docs] def find_include_names(self, node): return self.cre.findall(node.get_text_contents())
[docs] def scan(self, node, path=()): # cache the includes list in node so we only scan it once: if node.includes is not None: includes = node.includes else: includes = self.find_include_names(node) # Intern the names of the include files. Saves some memory # if the same header is included many times. node.includes = list(map(SCons.Util.silent_intern, includes)) # This is a hand-coded DSU (decorate-sort-undecorate, or # Schwartzian transform) pattern. The sort key is the raw name # of the file as specifed on the #include line (including the # " or <, since that may affect what file is found), which lets # us keep the sort order constant regardless of whether the file # is actually found in a Repository or locally. nodes = [] source_dir = node.get_dir() if callable(path): path = path() for include in includes: n, i = self.find_include(include, source_dir, path) if n is None: SCons.Warnings.warn( SCons.Warnings.DependencyWarning, "No dependency generated for file: %s " "(included from: %s) -- file not found" % (i, node), ) else: nodes.append((self.sort_key(include), n)) return [pair[1] for pair in sorted(nodes)]
[docs]class ClassicCPP(Classic): """ A Classic Scanner subclass which takes into account the type of bracketing used to include the file, and uses classic CPP rules for searching for the files based on the bracketing. Note that in order for this to work, the regular expression passed to the constructor must return the leading bracket in group 0, and the contained filename in group 1. """
[docs] @staticmethod def find_include(include, source_dir, path): include = list(map(SCons.Util.to_str, include)) if include[0] == '"': paths = (source_dir,) + tuple(path) else: paths = tuple(path) + (source_dir,) n = SCons.Node.FS.find_file(include[1], paths) i = SCons.Util.silent_intern(include[1]) return n, i
[docs] @staticmethod def sort_key(include): return SCons.Node.FS._my_normcase(' '.join(include))
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