1
2/*
3 * Copyright 2009 The Android Open Source Project
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9
10#ifndef SkTRegistry_DEFINED
11#define SkTRegistry_DEFINED
12
13#include "SkTypes.h"
14
15/** Template class that registers itself (in the constructor) into a linked-list
16    and provides a function-pointer. This can be used to auto-register a set of
17    services, e.g. a set of image codecs.
18 */
19template <typename T, typename P> class SkTRegistry : SkNoncopyable {
20public:
21    typedef T (*Factory)(P);
22
23    SkTRegistry(Factory fact) {
24#ifdef SK_BUILD_FOR_ANDROID
25        // work-around for double-initialization bug
26        {
27            SkTRegistry* reg = gHead;
28            while (reg) {
29                if (reg == this) {
30                    return;
31                }
32                reg = reg->fChain;
33            }
34        }
35#endif
36        fFact = fact;
37        fChain = gHead;
38        gHead = this;
39    }
40
41    static const SkTRegistry* Head() { return gHead; }
42
43    const SkTRegistry* next() const { return fChain; }
44    Factory factory() const { return fFact; }
45
46private:
47    Factory      fFact;
48    SkTRegistry* fChain;
49
50    static SkTRegistry* gHead;
51};
52
53// The caller still needs to declare an instance of this somewhere
54template <typename T, typename P> SkTRegistry<T, P>* SkTRegistry<T, P>::gHead;
55
56#endif
57