1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
|
/* -*-c++-*-
*
* $Id: Callback.h,v 1.1.1.1 2003/02/08 00:42:21 dairiki Exp $
*
* Copyright (C) 2003 Geoffrey T. Dairiki
*
* This file is part of Pyxine, Python bindings for xine.
*
* Pyxine is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* Pyxine is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#pragma interface
#ifndef _Callback_H
#define _Callback_H
#include "pxlib.h"
#include "Mutex.h"
#include "Traits.h"
extern "C" {
# include <Python.h>
}
BEGIN_PXLIB_NAMESPACE
class PythonException
: public Error
{
public:
PythonException()
: Error("A python exception occurred.")
{
PyErr_Print();
}
};
////////////////////////////////////////////////////////////////
class PythonObject
{
PyObject * ptr;
public:
PythonObject() : ptr(0) {}
PythonObject(PyObject * object, bool owned=true);
PythonObject(const PythonObject& that);
PythonObject& operator= (const PythonObject& that);
~PythonObject();
operator PyObject * () const { return ptr; }
operator bool () const { return ptr != 0; }
int refcnt () const { return ptr ? ptr->ob_refcnt : 0; } // debugging
};
////////////////////////////////////////////////////////////////
class PythonContext
{
struct rep_t {
int ref_cnt;
Mutex mutex;
PyThreadState * state;
rep_t();
~rep_t();
};
rep_t * rep;
friend class PythonGlobalLock;
operator PyThreadState * () const { return rep->state; }
operator Mutex * () const { return &rep->mutex; }
public:
PythonContext(); // You must call this from a python thread.
PythonContext(const PythonContext& c);
PythonContext& operator=(const PythonContext& c);
~PythonContext();
};
class PythonGlobalLock
{
MutexLock mutex_lock;
PythonContext& context;
PyThreadState * saved_state;
public:
PythonGlobalLock(PythonContext& context); // Never call this from a python thread
~PythonGlobalLock();
};
/////////////////////////////////////////////////////////////////////
template<class ArgType, class ReturnType>
class PythonCallback
{
public:
typedef ReturnType return_type;
typedef ArgType arg_type;
private:
mutable PythonContext context;
PythonObject callback;
public:
PythonCallback(PyObject *callable)
: callback(callable, false)
{
if (!PyCallable_Check(callable))
throw Error("callback object not callable");
}
return_type operator() (const arg_type& arg) const
{
PythonGlobalLock s(context);
PythonObject args = pack_tuple(arg);
PythonObject retval = PyObject_CallObject(callback, args);
return Traits<return_type>::unpack_tuple(retval);
}
};
////////////////////////////////////////////////////////////////
template <class Callback>
class CachedCallback
{
public:
typedef typename Callback::return_type return_type;
typedef typename Callback::arg_type arg_type;
private:
const std::string name;
Callback callback;
mutable Mutex mutex;
mutable bool cache_valid;
mutable arg_type cached_arg;
mutable return_type cached_retval;
public:
CachedCallback(const Callback& cb, const char * _name = "")
: name(_name), callback(cb), cache_valid(false) {}
void invalidate_cache() const
{
MutexLock lock(mutex); // this is paranoia
cache_valid = false;
}
return_type operator() (const arg_type& arg, int verbosity = 0) const
{
MutexLock lock(mutex);
if (!cache_valid || cached_arg != arg) {
if (verbosity > 1)
cerr << "Calling callback " << name << endl;
cached_retval = callback(arg);
cached_arg = arg;
cache_valid = true;
}
else {
if (verbosity > 2)
cerr << "Not calling callback " << name << endl;
}
return cached_retval;
}
};
////////////////////////////////////////////////////////////////
template<class ArgType, class ReturnType>
class CachedPythonCallback
: public CachedCallback<PythonCallback<ArgType, ReturnType> >
{
typedef CachedCallback<PythonCallback<ArgType, ReturnType> > super;
public:
CachedPythonCallback(PyObject *callable, const char * name="")
: super(callable, name)
{}
};
////////////////////////////////////////////////////////////////
END_PXLIB_NAMESPACE
#endif // !Callback_H
|
