Simple code to automatically extract dependencies from C/C++ files and generate Make target rules

cpp_deps.py

"""
Simple code to automatically extract dependencies from C/C++ files and
generate Make target rules
"""

def get_deps(filename):
    dep_set = set()
    with open(filename, 'r') as f:
        for line in f:
            tokens = line.strip().split()
            if len(tokens) > 0:
                if tokens[0] == "#include":
                    if tokens[1].startswith('"'):
                        dep_set.add(tokens[1][1:-1])

    len_ext = len(filename.split(".")[-1])
    headername = filename[:-len_ext]+"h"

    if headername in dep_set:
        try:
            with open(headername, 'r') as f:
                for line in f:
                    tokens = line.strip().split()
                    if len(tokens) > 0:
                        if tokens[0] == "#include":
                            if tokens[1].startswith('"'):
                                dep_set.add(tokens[1][1:-1])
        except FileNotFoundError:
            pass
    return dep_set

def rule_generator(filename, base_rule=r"${CXX} ${CXXFLAGS} -c "):

    dep_set = get_deps(filename)
    len_ext = len(filename.split(".")[-1])
    objectname = filename[:-len_ext]+"o"

    target = "{} : {} ".format(objectname, filename) + " ".join(dep_set)
    rule = "\t" + base_rule + filename
    return target, rule


if __name__ == "__main__":

    import glob

    for filename in glob.glob("*.cpp"):
        target, rule = rule_generator(filename)
        print(target)
        print(rule)