# This script creates a Windows .def file containing all the functions
# and static class variables to be exported by a DLL. The symbols are
# extracted from the output of dumpbin.
#
# To use this script, first generate a normal .lib library file, with
# no special command line options. Then create a .def file with this
# script:
#
#   makedeffile.py foo.lib foo 1.0 foo.def
#
# The command line arguments are the name of the .lib file, the
# library name, the library version, and the name of the .def file to
# output.
#
# Once you have a .def file, you can build a .dll, specifying the .def
# to the linker.
#
# An example of building a .dll from foo.cc:
#
# 1. Compile the source:
#
#      cl -c -O2 -MD -GX -Fofoo.o -Tpfoo.cc
#
# 2. Build a static library (It probably won't work on its own due to
#    the -MD switch to cl, but we just need it to get the symbols
#    out):
#
#      lib -out:foo_static.lib foo.o
#
# 3. Use this script to build a .def file:
#
#      makedeffile.py foo_static.lib foo 1.0 foo.def
#
# 4. Build the .dll and .lib with the def file.
#
#      link -out:foo.dll -dll -def:foo.def -implib:foo.lib foo.o
#
# If you are using this script so you can put omniORB stubs in a DLL,
# you also need to set some defines to correctly import symbols into
# the application. See chapter 12 of the omniORB manual for details.


# The way this script works is to process the output of dumpbin.
#
# The function symbols are extracted from the output using the
# following template:
# ... ........ SECT..  notype ()     External      | ?..................
#
# The static class variable symbols are extracted using the following
# template:
# ... ........ SECT..  notype        External      | ?[^?]..............
#
# Default destructors generated by the compiler and the symbols inside
# an anonymous namespace are excluded.
#
# Class variable and function symbols start with two ??  and class
# static variable and static function symbols start with one ?.

import re, sys, os, os.path

def usage(argv):
    sys.stderr.write("%s <lib file> <library name> <version> <def file>\n" %
                     os.path.basename(argv[0]))

def main(argv):
    try:
        _, libfile, binname, version, deffile = argv
    except ValueError:
        usage(argv)
        sys.exit(1)

    cmd = "DUMPBIN.EXE /SYMBOLS %s /OUT:%s" % (libfile, deffile)
    print(cmd)
    os.system(cmd)

    definitions = {}

    linere1 = re.compile(r"^[^ ]+ +[^ ]+ +SECT[^ ]+ +[^ ]+ +\(\) +External +\| +(\?[^ ]*)(.*)\n")
    linere2 = re.compile(r"^[^ ]+ +[^ ]+ +SECT[^ ]+ +[^ ]+ +External +\| +(\?[^?][^ ]*)(.*)\n")

    exclude = re.compile(r"deleting destructor[^(]+\(unsigned int\)|anonymous namespace")

    with open(deffile, "r") as dumped:
        while 1:
            line = dumped.readline()
            if line == "":
                break

            match = linere1.search(line) or linere2.search(line)
            if match:
                symbol = match.group(1)
                args   = match.group(2)

                if "std@" in symbol or exclude.search(args):
                    continue

                definitions[symbol] = None

    symbols = sorted(definitions.keys())

    print("Output %d symbols." % len(symbols))

    with open(deffile, "w") as out:
        if binname[4:].lower() == ".exe":
            out.write("NAME %s\n" % binname)
        else:
            out.write("LIBRARY %s\n" % binname)

        out.write("VERSION %s\n" % version)
        out.write("EXPORTS\n")

        for s in symbols:
            out.write(s + "\n")


if __name__ == "__main__":
    main(sys.argv)
