Chromium Code Reviews
chromiumcodereview-hr@appspot.gserviceaccount.com (chromiumcodereview-hr) | Please choose your nickname with Settings | Help | Chromium Project | Gerrit Changes | Sign out
(13)

Side by Side Diff: include/private/SkOncePtr.h

Issue 1334523002: Revert of Port uses of SkLazyPtr to SkOncePtr. (Closed) Base URL: https://skia.googlesource.com/skia.git@master
Patch Set: Created 5 years, 3 months ago
Use n/p to move between diff chunks; N/P to move between comments. Draft comments are only viewable by you.
Jump to:
View unified diff | Download patch
« no previous file with comments | « include/core/SkTypeface.h ('k') | src/core/SkBigPicture.h » ('j') | no next file with comments »
Toggle Intra-line Diffs ('i') | Expand Comments ('e') | Collapse Comments ('c') | Show Comments Hide Comments ('s')
OLDNEW
1 /* 1 /*
2 * Copyright 2015 Google Inc. 2 * Copyright 2015 Google Inc.
3 * 3 *
4 * Use of this source code is governed by a BSD-style license that can be 4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file. 5 * found in the LICENSE file.
6 */ 6 */
7 7
8 #ifndef SkOncePtr_DEFINED 8 #ifndef SkOncePtr_DEFINED
9 #define SkOncePtr_DEFINED 9 #define SkOncePtr_DEFINED
10 10
11 #include "SkAtomics.h" 11 #include "SkAtomics.h"
12 #include "SkUniquePtr.h"
13 12
14 template <typename T> class SkBaseOncePtr; 13 template <typename T> class SkStaticOnce;
15 14
16 // Use this to create a global static pointer that's intialized exactly once whe n you call get(). 15 // Use this to create a global static pointer that's intialized exactly once whe n you call get().
17 #define SK_DECLARE_STATIC_ONCE_PTR(type, name) namespace {} static SkBaseOncePtr <type> name 16 #define SK_DECLARE_STATIC_ONCE_PTR(type, name) namespace {} static SkStaticOnce< type> name
18 17
19 // Use this for a local or member pointer that's initialized exactly once when y ou call get(). 18 // Use this for a local or member pointer that's initialized exactly once when y ou call get().
20 template <typename T, typename Delete = skstd::default_delete<T>> 19 template <typename T>
21 class SkOncePtr : SkNoncopyable { 20 class SkOncePtr : SkNoncopyable {
22 public: 21 public:
23 SkOncePtr() { sk_bzero(this, sizeof(*this)); } 22 SkOncePtr() { sk_bzero(this, sizeof(*this)); }
24 ~SkOncePtr() { 23
25 if (T* ptr = (T*)*this) { 24 // SkOncePtr does not have a destructor and does not clean up the pointer. But you may, e.g.
26 Delete()(ptr); 25 // delete (T*)fOncePtr;
27 } 26 // SkSafeUnref((T*)fOncePtr);
28 } 27 // etc.
29 28
30 template <typename F> 29 template <typename F>
31 T* get(const F& f) const { 30 T* get(const F& f) const {
32 return fOnce.get(f); 31 return fOnce.get(f);
33 } 32 }
34 33
35 operator T*() const { 34 operator T*() const {
36 return (T*)fOnce; 35 return (T*)fOnce;
37 } 36 }
38 37
39 private: 38 private:
40 SkBaseOncePtr<T> fOnce; 39 SkStaticOnce<T> fOnce;
41 }; 40 };
42 41
43 /* TODO(mtklein): in next CL 42 /* TODO(mtklein): in next CL
44 typedef SkBaseOncePtr<void> SkOnceFlag; 43 typedef SkStaticOnce<void> SkOnceFlag;
45 #define SK_DECLARE_STATIC_ONCE(name) namespace {} static SkOnceFlag name 44 #define SK_DECLARE_STATIC_ONCE(name) namespace {} static SkOnceFlag name
46 45
47 template <typename F> 46 template <typename F>
48 inline void SkOnce(SkOnceFlag* once, const F& f) { 47 inline void SkOnce(SkOnceFlag* once, const F& f) {
49 once->get([&]{ f(); return (void*)2; }); 48 once->get([&]{ f(); return (void*)2; });
50 } 49 }
51 */ 50 */
52 51
53 // Implementation details below here! No peeking! 52 // Implementation details below here! No peeking!
54 53
55 template <typename T> 54 template <typename T>
56 class SkBaseOncePtr { 55 class SkStaticOnce {
57 public: 56 public:
58 template <typename F> 57 template <typename F>
59 T* get(const F& f) const { 58 T* get(const F& f) const {
60 uintptr_t state = fState.load(sk_memory_order_acquire); 59 uintptr_t state = fState.load(sk_memory_order_acquire);
61 if (state < 2) { 60 if (state < 2) {
62 if (state == 0) { 61 if (state == 0) {
63 // It looks like no one has tried to create our pointer yet. 62 // It looks like no one has tried to create our pointer yet.
64 // We try to claim that task by atomically swapping our state fr om '0' to '1'. 63 // We try to claim that task by atomically swapping our state fr om '0' to '1'.
65 if (fState.compare_exchange(&state, 1, sk_memory_order_relaxed, 64 if (fState.compare_exchange(&state, 1, sk_memory_order_relaxed,
66 sk_memory_order_relaxed)) { 65 sk_memory_order_relaxed)) {
(...skipping 27 matching lines...) Expand all
94 } 93 }
95 94
96 private: 95 private:
97 // fState == 0 --> we have not created our ptr yet 96 // fState == 0 --> we have not created our ptr yet
98 // fState == 1 --> someone is in the middle of creating our ptr 97 // fState == 1 --> someone is in the middle of creating our ptr
99 // else --> (T*)fState is our ptr 98 // else --> (T*)fState is our ptr
100 mutable SkAtomic<uintptr_t> fState; 99 mutable SkAtomic<uintptr_t> fState;
101 }; 100 };
102 101
103 #endif//SkOncePtr_DEFINED 102 #endif//SkOncePtr_DEFINED
OLDNEW
« no previous file with comments | « include/core/SkTypeface.h ('k') | src/core/SkBigPicture.h » ('j') | no next file with comments »

Powered by Google App Engine
This is Rietveld 408576698