1# Copyright (c) 2008 The Hewlett-Packard Development Company
2# All rights reserved.
3#
4# Redistribution and use in source and binary forms, with or without
5# modification, are permitted provided that the following conditions are
6# met: redistributions of source code must retain the above copyright
7# notice, this list of conditions and the following disclaimer;
8# redistributions in binary form must reproduce the above copyright
9# notice, this list of conditions and the following disclaimer in the
10# documentation and/or other materials provided with the distribution;
11# neither the name of the copyright holders nor the names of its
12# contributors may be used to endorse or promote products derived from
13# this software without specific prior written permission.
14#
15# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
18# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
19# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
21# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
25# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26#
27# Authors: Nathan Binkert
28
29from __future__ import print_function
30from __future__ import absolute_import
31
32# Simple importer that allows python to import data from a dict of
33# code objects.  The keys are the module path, and the items are the
34# filename and bytecode of the file.
35class CodeImporter(object):
36    def __init__(self):
37        self.modules = {}
38
39    def add_module(self, filename, abspath, modpath, code):
40        if modpath in self.modules:
41            raise AttributeError("%s already found in importer" % modpath)
42
43        self.modules[modpath] = (filename, abspath, code)
44
45    def find_module(self, fullname, path):
46        if fullname in self.modules:
47            return self
48
49        return None
50
51    def load_module(self, fullname):
52        # Because the importer is created and initialized in its own
53        # little sandbox (in init.cc), the globals that were available
54        # when the importer module was loaded and CodeImporter was
55        # defined are not available when load_module is actually
56        # called. Soooo, the imports must live here.
57        import imp
58        import os
59        import sys
60
61        try:
62            mod = sys.modules[fullname]
63        except KeyError:
64            mod = imp.new_module(fullname)
65            sys.modules[fullname] = mod
66
67        try:
68            mod.__loader__ = self
69            srcfile,abspath,code = self.modules[fullname]
70
71            override = os.environ.get('M5_OVERRIDE_PY_SOURCE', 'false').lower()
72            if override in ('true', 'yes') and  os.path.exists(abspath):
73                src = open(abspath, 'r').read()
74                code = compile(src, abspath, 'exec')
75
76            if os.path.basename(srcfile) == '__init__.py':
77                mod.__path__ = fullname.split('.')
78                mod.__package__ = fullname
79            else:
80                mod.__package__ = fullname.rpartition('.')[0]
81            mod.__file__ = srcfile
82
83            exec(code, mod.__dict__)
84        except Exception:
85            del sys.modules[fullname]
86            raise
87
88        return mod
89
90# Create an importer and add it to the meta_path so future imports can
91# use it.  There's currently nothing in the importer, but calls to
92# add_module can be used to add code.
93import sys
94importer = CodeImporter()
95add_module = importer.add_module
96sys.meta_path.append(importer)
97