1 /* 2 * Copyright 2014 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 GrProgramElement_DEFINED 9 #define GrProgramElement_DEFINED 10 11 #include "../private/SkTArray.h" 12 #include "SkRefCnt.h" 13 14 /** 15 * Note: We are converting GrProcessor from ref counting to a single owner model using move 16 * semantics. This class will be removed. 17 * 18 * This is used to track "refs" for two separate types GrProcessor ownership. A regular ref is owned 19 * by any client that may continue to issue draws that use the GrProgramElement. A recorded op or 20 * GrPipeline uses "pending executions" instead of refs. A pending execution is cleared after the 21 * draw is executed (or aborted). 22 * 23 * While a GrProgramElement is ref'ed any resources it owns are also ref'ed. However, once it gets 24 * into the state where it has pending executions AND no refs then it converts its ownership of 25 * its GrGpuResources from refs to pending IOs. The pending IOs allow the cache to track when it is 26 * safe to recycle a resource even though we still have buffered GrOps that read or write to the 27 * the resource. 28 * 29 * To make this work the subclass GrProcessor implements addPendingIOs, removeRefs, and 30 * pendingIOComplete. addPendingIOs adds pending reads/writes to GrGpuResources owned by the 31 * processor as appropriate when the processor is recorded in a GrOpList. removeRefs is called when 32 * the ref count reaches 0 and the GrProcessor is only owned by "pending executions". 33 * pendingIOComplete occurs if the resource is still owned by a ref but all recorded draws have been 34 * completed. Whenever pending executions and refs reach zero the processor is deleted. 35 * 36 * The GrProcessor may also implement notifyRefCntIsZero in order to change its ownership of child 37 * processors from ref to pending execution when the processor is first owned exclusively in pending 38 * execution mode. 39 */ 40 class GrProgramElement : public SkNoncopyable { 41 public: ~GrProgramElement()42 virtual ~GrProgramElement() { 43 // fRefCnt can be one when an effect is created statically using GR_CREATE_STATIC_EFFECT 44 SkASSERT((0 == fRefCnt || 1 == fRefCnt) && 0 == fPendingExecutions); 45 // Set to invalid values. 46 SkDEBUGCODE(fRefCnt = fPendingExecutions = -10;) 47 } 48 ref()49 void ref() const { 50 this->validate(); 51 // Once the ref cnt reaches zero it should never be ref'ed again. 52 SkASSERT(fRefCnt > 0); 53 ++fRefCnt; 54 this->validate(); 55 } 56 unref()57 void unref() const { 58 this->validate(); 59 --fRefCnt; 60 if (0 == fRefCnt) { 61 this->notifyRefCntIsZero(); 62 if (0 == fPendingExecutions) { 63 delete this; 64 return; 65 } else { 66 this->removeRefs(); 67 } 68 } 69 this->validate(); 70 } 71 validate()72 void validate() const { 73 #ifdef SK_DEBUG 74 SkASSERT(fRefCnt >= 0); 75 SkASSERT(fPendingExecutions >= 0); 76 SkASSERT(fRefCnt + fPendingExecutions > 0); 77 #endif 78 } 79 80 protected: GrProgramElement()81 GrProgramElement() : fRefCnt(1), fPendingExecutions(0) {} 82 addPendingExecution()83 void addPendingExecution() const { 84 this->validate(); 85 if (0 == fPendingExecutions) { 86 this->addPendingIOs(); 87 } 88 ++fPendingExecutions; 89 this->validate(); 90 } 91 completedExecution()92 void completedExecution() const { 93 this->validate(); 94 --fPendingExecutions; 95 if (0 == fPendingExecutions) { 96 if (0 == fRefCnt) { 97 delete this; 98 return; 99 } else { 100 this->pendingIOComplete(); 101 } 102 } 103 this->validate(); 104 } 105 106 private: 107 virtual void addPendingIOs() const = 0; 108 virtual void removeRefs() const = 0; 109 virtual void pendingIOComplete() const = 0; 110 111 /** This will be called when the ref cnt is zero. The object may or may not have pending 112 executions. */ 113 virtual void notifyRefCntIsZero() const = 0; 114 115 mutable int32_t fRefCnt; 116 // Count of deferred executions not yet issued to the 3D API. 117 mutable int32_t fPendingExecutions; 118 119 // Only these classes can access addPendingExecution() and completedExecution(). 120 template <typename T> friend class GrPendingProgramElement; 121 friend class GrProcessorSet; 122 123 typedef SkNoncopyable INHERITED; 124 }; 125 126 #endif 127