proxy.py revision 3109:c3956807347f 
1# Copyright (c) 2004-2006 The Regents of The University of Michigan
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: Steve Reinhardt
28#          Nathan Binkert
29
30#####################################################################
31#
32# Proxy object support.
33#
34#####################################################################
35
36class BaseProxy(object):
37    def __init__(self, search_self, search_up):
38        self._search_self = search_self
39        self._search_up = search_up
40        self._multiplier = None
41
42    def __str__(self):
43        if self._search_self and not self._search_up:
44            s = 'Self'
45        elif not self._search_self and self._search_up:
46            s = 'Parent'
47        else:
48            s = 'ConfusedProxy'
49        return s + '.' + self.path()
50
51    def __setattr__(self, attr, value):
52        if not attr.startswith('_'):
53            raise AttributeError, \
54                  "cannot set attribute '%s' on proxy object" % attr
55        super(BaseProxy, self).__setattr__(attr, value)
56
57    # support multiplying proxies by constants
58    def __mul__(self, other):
59        if not isinstance(other, (int, long, float)):
60            raise TypeError, "Proxy multiplier must be integer"
61        if self._multiplier == None:
62            self._multiplier = other
63        else:
64            # support chained multipliers
65            self._multiplier *= other
66        return self
67
68    __rmul__ = __mul__
69
70    def _mulcheck(self, result):
71        if self._multiplier == None:
72            return result
73        return result * self._multiplier
74
75    def unproxy(self, base):
76        obj = base
77        done = False
78
79        if self._search_self:
80            result, done = self.find(obj)
81
82        if self._search_up:
83            while not done:
84                obj = obj._parent
85                if not obj:
86                    break
87                result, done = self.find(obj)
88
89        if not done:
90            raise AttributeError, \
91                  "Can't resolve proxy '%s' of type '%s' from '%s'" % \
92                  (self.path(), self._pdesc.ptype_str, base.path())
93
94        if isinstance(result, BaseProxy):
95            if result == self:
96                raise RuntimeError, "Cycle in unproxy"
97            result = result.unproxy(obj)
98
99        return self._mulcheck(result)
100
101    def getindex(obj, index):
102        if index == None:
103            return obj
104        try:
105            obj = obj[index]
106        except TypeError:
107            if index != 0:
108                raise
109            # if index is 0 and item is not subscriptable, just
110            # use item itself (so cpu[0] works on uniprocessors)
111        return obj
112    getindex = staticmethod(getindex)
113
114    # This method should be called once the proxy is assigned to a
115    # particular parameter or port to set the expected type of the
116    # resolved proxy
117    def set_param_desc(self, pdesc):
118        self._pdesc = pdesc
119
120class AttrProxy(BaseProxy):
121    def __init__(self, search_self, search_up, attr):
122        super(AttrProxy, self).__init__(search_self, search_up)
123        self._attr = attr
124        self._modifiers = []
125
126    def __getattr__(self, attr):
127        # python uses __bases__ internally for inheritance
128        if attr.startswith('_'):
129            return super(AttrProxy, self).__getattr__(self, attr)
130        if hasattr(self, '_pdesc'):
131            raise AttributeError, "Attribute reference on bound proxy"
132        self._modifiers.append(attr)
133        return self
134
135    # support indexing on proxies (e.g., Self.cpu[0])
136    def __getitem__(self, key):
137        if not isinstance(key, int):
138            raise TypeError, "Proxy object requires integer index"
139        self._modifiers.append(key)
140        return self
141
142    def find(self, obj):
143        try:
144            val = getattr(obj, self._attr)
145        except:
146            return None, False
147        while isproxy(val):
148            val = val.unproxy(obj)
149        for m in self._modifiers:
150            if isinstance(m, str):
151                val = getattr(val, m)
152            elif isinstance(m, int):
153                val = val[m]
154            else:
155                assert("Item must be string or integer")
156            while isproxy(val):
157                val = val.unproxy(obj)
158        return val, True
159
160    def path(self):
161        p = self._attr
162        for m in self._modifiers:
163            if isinstance(m, str):
164                p += '.%s' % m
165            elif isinstance(m, int):
166                p += '[%d]' % m
167            else:
168                assert("Item must be string or integer")
169        return p
170
171class AnyProxy(BaseProxy):
172    def find(self, obj):
173        return obj.find_any(self._pdesc.ptype)
174
175    def path(self):
176        return 'any'
177
178def isproxy(obj):
179    if isinstance(obj, (BaseProxy, params.EthernetAddr)):
180        return True
181    elif isinstance(obj, (list, tuple)):
182        for v in obj:
183            if isproxy(v):
184                return True
185    return False
186
187class ProxyFactory(object):
188    def __init__(self, search_self, search_up):
189        self.search_self = search_self
190        self.search_up = search_up
191
192    def __getattr__(self, attr):
193        if attr == 'any':
194            return AnyProxy(self.search_self, self.search_up)
195        else:
196            return AttrProxy(self.search_self, self.search_up, attr)
197
198# global objects for handling proxies
199Parent = ProxyFactory(search_self = False, search_up = True)
200Self = ProxyFactory(search_self = True, search_up = False)
201
202# limit exports on 'from proxy import *'
203__all__ = ['Parent', 'Self']
204
205# see comment on imports at end of __init__.py.
206import params # for EthernetAddr
207