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| 1 /* |
| 2 * Copyright 2015 Google Inc. |
| 3 * |
| 4 * Use of this source code is governed by a BSD-style license that can be |
| 5 * found in the LICENSE file. |
| 6 */ |
| 7 |
| 8 #ifndef GrVkResource_DEFINED |
| 9 #define GrVkResource_DEFINED |
| 10 |
| 11 #include "SkAtomics.h" |
| 12 #include "SkTDynamicHash.h" |
| 13 #include "SkRandom.h" |
| 14 |
| 15 class GrVkGpu; |
| 16 |
| 17 // uncomment to enable tracing of resource refs |
| 18 //#ifdef SK_DEBUG |
| 19 //#define SK_TRACE_VK_RESOURCES |
| 20 //#endif |
| 21 |
| 22 /** \class GrVkResource |
| 23 |
| 24 GrVkResource is the base class for Vulkan resources that may be shared by mult
iple |
| 25 objects. When an existing owner wants to share a reference, it calls ref(). |
| 26 When an owner wants to release its reference, it calls unref(). When the |
| 27 shared object's reference count goes to zero as the result of an unref() |
| 28 call, its (virtual) destructor is called. It is an error for the |
| 29 destructor to be called explicitly (or via the object going out of scope on |
| 30 the stack or calling delete) if getRefCnt() > 1. |
| 31 |
| 32 This is nearly identical to SkRefCntBase. The exceptions are that unref() |
| 33 takes a GrVkGpu, and any derived classes must implement freeGPUData() and |
| 34 possibly abandonSubResources(). |
| 35 */ |
| 36 |
| 37 class GrVkResource : SkNoncopyable { |
| 38 public: |
| 39 // Simple refCount tracing, to ensure that everything ref'ed is unref'ed. |
| 40 #ifdef SK_TRACE_VK_RESOURCES |
| 41 static const uint32_t& GetKey(const GrVkResource& r) { return r.fKey; } |
| 42 static uint32_t Hash(const uint32_t& k) { return k; } |
| 43 static SkTDynamicHash<GrVkResource, uint32_t> fTrace; |
| 44 static SkRandom fRandom; |
| 45 #endif |
| 46 |
| 47 /** Default construct, initializing the reference count to 1. |
| 48 */ |
| 49 GrVkResource() : fRefCnt(1) { |
| 50 #ifdef SK_TRACE_VK_RESOURCES |
| 51 fKey = fRandom.nextU(); |
| 52 fTrace.add(this); |
| 53 #endif |
| 54 } |
| 55 |
| 56 /** Destruct, asserting that the reference count is 1. |
| 57 */ |
| 58 virtual ~GrVkResource() { |
| 59 #ifdef SK_DEBUG |
| 60 SkASSERTF(fRefCnt == 1, "fRefCnt was %d", fRefCnt); |
| 61 fRefCnt = 0; // illegal value, to catch us if we reuse after delete |
| 62 #endif |
| 63 } |
| 64 |
| 65 #ifdef SK_DEBUG |
| 66 /** Return the reference count. Use only for debugging. */ |
| 67 int32_t getRefCnt() const { return fRefCnt; } |
| 68 #endif |
| 69 |
| 70 /** May return true if the caller is the only owner. |
| 71 * Ensures that all previous owner's actions are complete. |
| 72 */ |
| 73 bool unique() const { |
| 74 if (1 == sk_atomic_load(&fRefCnt, sk_memory_order_acquire)) { |
| 75 // The acquire barrier is only really needed if we return true. It |
| 76 // prevents code conditioned on the result of unique() from running |
| 77 // until previous owners are all totally done calling unref(). |
| 78 return true; |
| 79 } |
| 80 return false; |
| 81 } |
| 82 |
| 83 /** Increment the reference count. |
| 84 Must be balanced by a call to unref() or unrefAndFreeResources(). |
| 85 */ |
| 86 void ref() const { |
| 87 SkASSERT(fRefCnt > 0); |
| 88 (void)sk_atomic_fetch_add(&fRefCnt, +1, sk_memory_order_relaxed); // No
barrier required. |
| 89 } |
| 90 |
| 91 /** Decrement the reference count. If the reference count is 1 before the |
| 92 decrement, then delete the object. Note that if this is the case, then |
| 93 the object needs to have been allocated via new, and not on the stack. |
| 94 Any GPU data associated with this resource will be freed before it's del
eted. |
| 95 */ |
| 96 void unref(const GrVkGpu* gpu) const { |
| 97 SkASSERT(fRefCnt > 0); |
| 98 SkASSERT(gpu); |
| 99 // A release here acts in place of all releases we "should" have been do
ing in ref(). |
| 100 if (1 == sk_atomic_fetch_add(&fRefCnt, -1, sk_memory_order_acq_rel)) { |
| 101 // Like unique(), the acquire is only needed on success, to make sur
e |
| 102 // code in internal_dispose() doesn't happen before the decrement. |
| 103 this->internal_dispose(gpu); |
| 104 } |
| 105 } |
| 106 |
| 107 /** Unref without freeing GPU data. Used only when we're abandoning the reso
urce */ |
| 108 void unrefAndAbandon() const { |
| 109 SkASSERT(fRefCnt > 0); |
| 110 // A release here acts in place of all releases we "should" have been do
ing in ref(). |
| 111 if (1 == sk_atomic_fetch_add(&fRefCnt, -1, sk_memory_order_acq_rel)) { |
| 112 // Like unique(), the acquire is only needed on success, to make sur
e |
| 113 // code in internal_dispose() doesn't happen before the decrement. |
| 114 this->internal_dispose(); |
| 115 } |
| 116 } |
| 117 |
| 118 #ifdef SK_DEBUG |
| 119 void validate() const { |
| 120 SkASSERT(fRefCnt > 0); |
| 121 } |
| 122 #endif |
| 123 |
| 124 private: |
| 125 /** Must be implemented by any subclasses. |
| 126 * Deletes any Vk data associated with this resource |
| 127 */ |
| 128 virtual void freeGPUData(const GrVkGpu* gpu) const = 0; |
| 129 |
| 130 /** Must be overridden by subclasses that themselves store GrVkResources. |
| 131 * Will unrefAndAbandon those resources without deleting the underlying Vk
data |
| 132 */ |
| 133 virtual void abandonSubResources() const {} |
| 134 |
| 135 /** |
| 136 * Called when the ref count goes to 0. Will free Vk resources. |
| 137 */ |
| 138 void internal_dispose(const GrVkGpu* gpu) const { |
| 139 this->freeGPUData(gpu); |
| 140 #ifdef SK_TRACE_VK_RESOURCES |
| 141 fTrace.remove(GetKey(*this)); |
| 142 #endif |
| 143 SkASSERT(0 == fRefCnt); |
| 144 fRefCnt = 1; |
| 145 delete this; |
| 146 } |
| 147 |
| 148 /** |
| 149 * Internal_dispose without freeing Vk resources. Used when we've lost cont
ext. |
| 150 */ |
| 151 void internal_dispose() const { |
| 152 this->abandonSubResources(); |
| 153 #ifdef SK_TRACE_VK_RESOURCES |
| 154 fTrace.remove(GetKey(*this)); |
| 155 #endif |
| 156 SkASSERT(0 == fRefCnt); |
| 157 fRefCnt = 1; |
| 158 delete this; |
| 159 } |
| 160 |
| 161 mutable int32_t fRefCnt; |
| 162 #ifdef SK_TRACE_VK_RESOURCES |
| 163 uint32_t fKey; |
| 164 #endif |
| 165 |
| 166 typedef SkNoncopyable INHERITED; |
| 167 }; |
| 168 |
| 169 |
| 170 #endif |
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