ParseDepends SCons tool

parse_depends.py

"""
Use the C preprocessor to generate include dependencies

The SCons ParseDepends can parse the dependency files output by the
preprocessor, however this requires a rebuild as the dependency files are
updated after the compiler is run once.

See the `-M` flags in `man gcc` for more info.
This implementation was taken from
https://bitbucket.org/scons/scons/wiki/ParseDepends

The entire example on that link is:
###############################################################################
#   If you want to extract the dependencies (and call ParseDepends) before
#   building the object files, the only viable solution is to use a multi-stage
#   builder with a source scanner:
##################################
    def parsedep(node, env, path):
            print "ParseDepends(%s)" % str(node)
            ParseDepends(str(node))
            return []

    def parsecheck(node, env):
            return node.exists()

    depscan = Scanner(function = parsedep, skeys = ['.d'],
                      scan_check=parsecheck)

    depbuild = Builder(action = '$CC -M -MF $TARGET $CCFLAGS -c $SOURCE',
                       suffix='.d', src_suffix='.c')

    depparse = Builder(action = Copy('$TARGET', '$SOURCE'),
                       suffix='.dep',
                       src_builder=depbuild,
                       source_scanner=depscan)

    env = Environment(BUILDERS = {'ExtractDependencies': depparse})

    dep = env.ExtractDependencies('hello.c')

    obj = env.Object('hello.c')
    env.Requires(obj, dep)
    env.Program(obj)
###############################################################################

This files combines part of those steps as a SCons Tool.
"""
import SCons


def parsedep(node, env, path):
        print "ParseDepends(%s)" % str(node)
        env.ParseDepends(str(node))
        return []

def parsecheck(node, env):
    return node.exists()


depscan = SCons.Scanner.Base(
    function=parsedep,
    skeys=['.d'],
    scan_check=parsecheck)

depbuild = SCons.Builder.Builder(
    action='$CC -M -MG -MF $TARGET $CFLAGS $CCFLAGS $_CCCOMCOM -c $SOURCE',
    suffix='.d',
    src_suffix=['.c', '.S'])

ExtractDependencies = SCons.Builder.Builder(
    action=SCons.Defaults.Copy('$TARGET', '$SOURCE'),
    suffix='.dep',
    src_builder=depbuild,
    source_scanner=depscan)

def ObjectsWithDependencies(env, sources, *args, **kwargs):
    dep = env.ExtractDependencies(sources)
    obj = env.Object(sources, *args, **kwargs)
    env.Requires(obj, dep)
    return (obj, dep)


def generate(env):
    """
    Add required methods and environment variables
    """
    env.Append(BUILDERS={'ExtractDependencies': ExtractDependencies})
    env.AddMethod(ObjectsWithDependencies, 'ObjectsWithDependencies')


def exists(env):
    """
    This tool requires no additional dependencies
    """
    return True