# MIT License
#
# Copyright The SCons Foundation
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be included
# in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
"""Dependency scanner for C/C++ code.
Two scanners are defined here: the default CScanner, and the optional
CConditionalScanner, which must be explicitly selected by calling
add_scanner() for each affected suffix.
"""
from typing import Dict
import SCons.Node.FS
import SCons.cpp
import SCons.Util
from . import ClassicCPP, FindPathDirs
[docs]
class SConsCPPScanner(SCons.cpp.PreProcessor):
"""SCons-specific subclass of the cpp.py module's processing.
We subclass this so that: 1) we can deal with files represented
by Nodes, not strings; 2) we can keep track of the files that are
missing.
"""
def __init__(self, *args, **kwargs) -> None:
super().__init__(*args, **kwargs)
self.missing = []
[docs]
def initialize_result(self, fname) -> None:
self.result = SCons.Util.UniqueList([fname])
[docs]
def finalize_result(self, fname):
return self.result[1:]
[docs]
def find_include_file(self, t):
keyword, quote, fname = t
result = SCons.Node.FS.find_file(fname, self.searchpath[quote])
if not result:
self.missing.append((fname, self.current_file))
return result
[docs]
def read_file(self, file) -> str:
try:
return file.rfile().get_text_contents()
except OSError as e:
self.missing.append((file, self.current_file))
return ''
[docs]
def dictify_CPPDEFINES(env, replace: bool = False) -> dict:
"""Return CPPDEFINES converted to a dict for preprocessor emulation.
The concept is similar to :func:`~SCons.Defaults.processDefines`:
turn the values stored in an internal form in ``env['CPPDEFINES']``
into one needed for a specific context - in this case the cpp-like
work the C/C++ scanner will do. We can't reuse ``processDefines``
output as that's a list of strings for the command line. We also can't
pass the ``CPPDEFINES`` variable directly to the ``dict`` constructor,
as SCons allows it to be stored in several different ways - it's only
after ``Append`` and relatives has been called we know for sure it will
be a deque of tuples.
If requested (*replace* is true), simulate some of the macro
replacement that would take place if an actual preprocessor ran,
to avoid some conditional inclusions comeing out wrong. A bit
of an edge case, but does happen (GH #4623). See 6.10.5 in the C
standard and 15.6 in the C++ standard).
Args:
replace: if true, simulate macro replacement
.. versionchanged:: 4.9.0
Simple macro replacement added, and *replace* arg to enable it.
"""
def _replace(mapping: Dict) -> Dict:
"""Simplistic macro replacer for dictify_CPPDEFINES.
Scan *mapping* for a value that is the same as a key in the dict,
and replace with the value of that key; the process is repeated a few
times, but not forever in case someone left a case that can't be
fully resolved. This is a cheap approximation of the preprocessor's
macro replacement rules with no smarts - it doesn't "look inside"
the values, so only triggers on object-like macros, not on
function-like macros, and will not work on complex values, e.g.
a value like ``(1UL << PR_MTE_TCF_SHIFT)`` would not have
``PR_MTE_TCF_SHIFT`` replaced if that was also a key in ``CPPDEFINES``.
Args:
mapping: a dictionary representing macro names and replacements.
Returns:
a dictionary with replacements made.
"""
old_ns = mapping
loops = 0
while loops < 5: # don't recurse forever in case there's circular data
# this was originally written as a dict comprehension, but unrolling
# lets us add a finer-grained check for whether another loop is
# needed, rather than comparing two dicts to see if one changed.
again = False
ns = {}
for k, v in old_ns.items():
if v in old_ns:
ns[k] = old_ns[v]
if not again and ns[k] != v:
again = True
else:
ns[k] = v
if not again:
break
old_ns = ns
loops += 1
return ns
cppdefines = env.get('CPPDEFINES', {})
if not cppdefines:
return {}
if SCons.Util.is_Tuple(cppdefines):
# single macro defined in a tuple
try:
return {cppdefines[0]: cppdefines[1]}
except IndexError:
return {cppdefines[0]: None}
if SCons.Util.is_Sequence(cppdefines):
# multiple (presumably) macro defines in a deque, list, etc.
result = {}
for c in cppdefines:
if SCons.Util.is_Sequence(c):
try:
result[c[0]] = c[1]
except IndexError:
# could be a one-item sequence
result[c[0]] = None
elif SCons.Util.is_String(c):
try:
name, value = c.split('=')
result[name] = value
except ValueError:
result[c] = None
else:
# don't really know what to do here
result[c] = None
if replace:
return _replace(result)
return(result)
if SCons.Util.is_String(cppdefines):
# single macro define in a string
try:
name, value = cppdefines.split('=')
return {name: value}
except ValueError:
return {cppdefines: None}
if SCons.Util.is_Dict(cppdefines):
# already in the desired form
if replace:
return _replace(cppdefines)
return cppdefines
return {cppdefines: None}
[docs]
class SConsCPPScannerWrapper:
"""The SCons wrapper around a cpp.py scanner.
This is the actual glue between the calling conventions of generic
SCons scanners, and the (subclass of) cpp.py class that knows how
to look for #include lines with reasonably real C-preprocessor-like
evaluation of #if/#ifdef/#else/#elif lines.
"""
def __init__(self, name, variable) -> None:
self.name = name
self.path = FindPathDirs(variable)
def __call__(self, node, env, path=()):
cpp = SConsCPPScanner(
current=node.get_dir(),
cpppath=path,
dict=dictify_CPPDEFINES(env, replace=True),
)
result = cpp(node)
for included, includer in cpp.missing:
SCons.Warnings.warn(
SCons.Warnings.DependencyWarning,
"No dependency generated for file: %s (included from: %s) "
"-- file not found" % (included, includer),
)
return result
[docs]
def recurse_nodes(self, nodes):
return nodes
[docs]
def select(self, node):
return self
[docs]
def CScanner():
"""Return a prototype Scanner instance for scanning source files
that use the C pre-processor"""
# Here's how we would (or might) use the CPP scanner code above that
# knows how to evaluate #if/#ifdef/#else/#elif lines when searching
# for #includes. This is commented out for now until we add the
# right configurability to let users pick between the scanners.
# return SConsCPPScannerWrapper("CScanner", "CPPPATH")
cs = ClassicCPP(
"CScanner",
"$CPPSUFFIXES",
"CPPPATH",
r'^[ \t]*#[ \t]*(?:include|import)[ \t]*(<|")([^>"]+)(>|")',
)
return cs
#
# ConditionalScanner
#
[docs]
class SConsCPPConditionalScanner(SCons.cpp.PreProcessor):
"""SCons-specific subclass of the cpp.py module's processing.
We subclass this so that: 1) we can deal with files represented
by Nodes, not strings; 2) we can keep track of the files that are
missing.
"""
def __init__(self, *args, **kwargs) -> None:
super().__init__(*args, **kwargs)
self.missing = []
self._known_paths = []
[docs]
def initialize_result(self, fname) -> None:
self.result = SCons.Util.UniqueList([fname])
[docs]
def find_include_file(self, t):
keyword, quote, fname = t
paths = tuple(self._known_paths) + self.searchpath[quote]
if quote == '"':
paths = (self.current_file.dir,) + paths
result = SCons.Node.FS.find_file(fname, paths)
if result:
result_path = result.get_abspath()
for p in self.searchpath[quote]:
if result_path.startswith(p.get_abspath()):
self._known_paths.append(p)
break
else:
self.missing.append((fname, self.current_file))
return result
[docs]
def read_file(self, file) -> str:
try:
return file.rfile().get_text_contents()
except OSError:
self.missing.append((file, self.current_file))
return ""
[docs]
class SConsCPPConditionalScannerWrapper:
"""
The SCons wrapper around a cpp.py scanner.
This is the actual glue between the calling conventions of generic
SCons scanners, and the (subclass of) cpp.py class that knows how
to look for #include lines with reasonably real C-preprocessor-like
evaluation of #if/#ifdef/#else/#elif lines.
"""
def __init__(self, name, variable) -> None:
self.name = name
self.path = FindPathDirs(variable)
def __call__(self, node, env, path=(), depth=-1):
cpp = SConsCPPConditionalScanner(
current=node.get_dir(),
cpppath=path,
dict=dictify_CPPDEFINES(env),
depth=depth,
)
result = cpp(node)
for included, includer in cpp.missing:
fmt = "No dependency generated for file: %s (included from: %s) -- file not found"
SCons.Warnings.warn(
SCons.Warnings.DependencyWarning, fmt % (included, includer)
)
return result
[docs]
def recurse_nodes(self, nodes):
return nodes
[docs]
def select(self, node):
return self
[docs]
def CConditionalScanner():
"""
Return an advanced conditional Scanner instance for scanning source files
Interprets C/C++ Preprocessor conditional syntax
(#ifdef, #if, defined, #else, #elif, etc.).
"""
return SConsCPPConditionalScannerWrapper("CConditionalScanner", "CPPPATH")
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