recipes/llvm.resources/merge_headers.py

#!/usr/bin/env python
# Copyright 2018 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Merges headers from two different paths, surrounding differing blocks with macro
guards that can be specified via command line argument.

Usage:
  python merge_headers.py --def1=__aarch64__ --def2=__x86_64__ out/arm64 out/x64
"""

import argparse
import difflib
import filecmp
import os
import shutil
import sys


def copyfile(src_a, src_b, dst, def_a=None, def_b=None):
    if filecmp.cmp(src_a, src_b):
        print "Copy: %s" % dst
        shutil.copyfile(src_a, dst)
        return

    with open(src_a, "r") as f:
        a = f.readlines()
    with open(src_b, "r") as f:
        b = f.readlines()

    s = difflib.SequenceMatcher(None, a, b)
    out = []
    blocks = s.get_matching_blocks()
    for i in range(0, len(blocks) - 1):
        out.extend(a[blocks[i].a : blocks[i].a + blocks[i].size])
        diff_a = a[blocks[i].a + blocks[i].size : blocks[i + 1].a]
        if diff_a and def_a:
            out.extend(["#ifdef %s\n" % def_a] + diff_a + ["#endif\n"])
        diff_b = b[blocks[i].b + blocks[i].size : blocks[i + 1].b]
        if diff_b and def_b:
            out.extend(["#ifdef %s\n" % def_b] + diff_b + ["#endif\n"])

    with open(dst, "w") as f:
        print "Merge: %s" % dst
        f.writelines(out)


def copytree(src_a, src_b, dst, def_a=None, def_b=None):
    names = os.listdir(src_a)
    if not os.path.isdir(dst):
        os.makedirs(dst)
    for name in names:
        srcname_a = os.path.join(src_a, name)
        srcname_b = os.path.join(src_b, name)
        dstname = os.path.join(dst, name)
        try:
            if os.path.islink(srcname_a):
                linkto = os.readlink(srcname_a)
                os.symlink(linkto, dstname)
            elif os.path.isdir(srcname_a):
                copytree(srcname_a, srcname_b, dstname, def_a, def_b)
            else:
                copyfile(srcname_a, srcname_b, dstname, def_a, def_b)
        except Exception:
            shutil.rmtree(dst, ignore_errors=True)
            raise


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument("-o", "--out", default=os.getcwd(), help="destination path")
    parser.add_argument("--def1", help="define value for first path")
    parser.add_argument("--def2", help="define value for second path")
    parser.add_argument("path1", help="first path")
    parser.add_argument("path2", help="second path")
    args = parser.parse_args()

    copytree(args.path1, args.path2, args.out, args.def1, args.def2)

    return 0


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