install.py.in

#!/usr/bin/env python

import argparse
import filecmp
import os
import shutil

subdirs = set()
prefix = None


def needs_install(src, dst):
    # Get canonical destination.
    dst_full = os.path.join(prefix, dst)

    # Check if destination exists.
    if not os.path.exists(dst_full):
        # Destination doesn't exist -> installation needed.
        return True

    # Check if files are different.
    if filecmp.cmp(src, dst_full, shallow=False):
        # Files are the same -> no installation needed.
        return False

    # File needs to be installed.
    return True


def install(src, dst):
    global subdirs

    # Ensure destination subdirectory exists, creating it if necessary.
    subdir = os.path.dirname(dst)
    if subdir not in subdirs:
        subdir_full = os.path.join(prefix, subdir)
        if not os.path.exists(subdir_full):
            os.makedirs(subdir_full)
        subdirs.add(subdir)

    # Install file, if not up to date.
    if needs_install(src, dst):
        print("[Installing] %s" % dst)
        dst_full = os.path.join(prefix, dst)
        if os.path.exists(dst_full):
            os.remove(dst_full)
        shutil.copy2(src, dst_full)

    else:
        print("[Up to date] %s" % dst)


def main(args):
    global prefix

    # Set up options.
    parser = argparse.ArgumentParser()
    parser.add_argument('prefix', type=str, help='Install prefix')
    args = parser.parse_args(args)

    # Get install prefix.
    prefix = args.prefix

    # Because Bazel executes us in a strange working directory and not the
    # working directory of the user's shell, enforce that the install
    # location is an absolute path so that the user is not surprised.
    if not os.path.isabs(prefix):
        import sys
        sys.stderr.write(
            "Install prefix must be an absolute path (got %r)\n"
            % prefix)
        sys.exit(1)

    # Execute the install actions.
    <<actions>>


if __name__ == "__main__":
    import sys
    main(sys.argv[1:])