sym_link.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
 
import os
import errno
from SCons.Script import GetOption
from SCons.Builder import Builder
 
# define relpath for python < 2.6
if not hasattr(os.path, 'relpath'):
 
    def relpath(path, start=os.path.curdir):
        """Return a relative version of a path"""
 
        if not path:
            raise ValueError('no path specified')
 
        start_list = os.path.abspath(start).split(os.path.sep)
        path_list = os.path.abspath(path).split(os.path.sep)
 
        # Work out how much of the filepath is shared by start and path.
        i = len(os.path.commonprefix([start_list, path_list]))
 
        rel_list = [os.path.pardir] * (len(start_list) - i) + path_list[i:]
        if not rel_list:
            return os.path.curdir
        return os.path.join(*rel_list)
 
    os.path.relpath = relpath
 
 
def create_symlink(target, source, env):
    """Create a symbolic link from source to target"""
 
    source = os.path.relpath(source, os.path.dirname(target))
    try:
        os.symlink(source, target)
    except OSError as e:
        # target might exist if source was moved!
        if e.errno == errno.EEXIST:
            os.remove(target)
            os.symlink(source, target)
        else:
            raise e
    return 0
 
 
copy_file = Builder(action='cp -pf $SOURCE $TARGET')
copy_file.action.cmdstr = '${COPYCOMSTR}'
 
 
def generate(env):
    if not GetOption('no-symlink'):
        env['INSTALL'] = create_symlink
    env['BUILDERS']['Copy'] = copy_file
 
 
def exists(env):
    return True