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 class GrGpuResourceRef; 15 16 /** 17 * Note: We are converting GrProcessor from ref counting to a single owner model using move 18 * semantics. This class will be removed. 19 * 20 * Base class for GrProcessor. This exists to manage transitioning a GrProcessor from being owned by 21 * a client to being scheduled for execution. While a GrProcessor is ref'ed by drawing code its 22 * GrGpu resources must also be ref'ed to prevent incorrectly recycling them through the cache. 23 * However, once the GrProcessor is baked into a GrPipeline and the drawing code has stopped ref'ing 24 * it, it's internal resources can be recycled in some cases. 25 * 26 * We track this using two types of refs on GrProgramElement. A regular ref is owned by any client 27 * that may continue to issue draws that use the GrProgramElement. The GrPipeline owns "pending 28 * executions" instead of refs. A pending execution is cleared by ~GrPipeline(). 29 * 30 * While a GrProgramElement is ref'ed any resources it owns are also ref'ed. However, once it gets 31 * into the state where it has pending executions AND no refs then it converts its ownership of 32 * its GrGpuResources from refs to pending IOs. The pending IOs allow the cache to track when it is 33 * safe to recycle a resource even though we still have buffered GrOps that read or write to the 34 * the resource. 35 * 36 * To make this work the subclass, GrProcessor, implements addPendingIOs and pendingIOComplete. The 37 * former adds pending reads/writes as appropriate when the processor is recorded in a GrOpList. The 38 * latter removes them after the op list executes the operation. These calls must propagate to any 39 * children processors. Similarly, the subclass implements a removeRefs function in order to remove 40 * refs from resources once the processor is only owned for pending execution. 41 */ 42 template<typename DERIVED> class GrProgramElement : public SkNoncopyable { 43 public: 44 virtual ~GrProgramElement() { 45 // fRefCnt can be one when an effect is created statically using GR_CREATE_STATIC_EFFECT 46 SkASSERT((0 == fRefCnt || 1 == fRefCnt) && 0 == fPendingExecutions); 47 // Set to invalid values. 48 SkDEBUGCODE(fRefCnt = fPendingExecutions = -10;) 49 } 50 51 void ref() const { 52 this->validate(); 53 // Once the ref cnt reaches zero it should never be ref'ed again. 54 SkASSERT(fRefCnt > 0); 55 ++fRefCnt; 56 this->validate(); 57 } 58 59 void unref() const { 60 this->validate(); 61 --fRefCnt; 62 if (0 == fRefCnt) { 63 this->notifyRefCntIsZero(); 64 if (0 == fPendingExecutions) { 65 delete this; 66 return; 67 } else { 68 static_cast<const DERIVED*>(this)->removeRefs(); 69 } 70 } 71 this->validate(); 72 } 73 74 void validate() const { 75 #ifdef SK_DEBUG 76 SkASSERT(fRefCnt >= 0); 77 SkASSERT(fPendingExecutions >= 0); 78 SkASSERT(fRefCnt + fPendingExecutions > 0); 79 #endif 80 } 81 82 protected: 83 GrProgramElement() : fRefCnt(1), fPendingExecutions(0) {} 84 85 void addPendingExecution() const { 86 this->validate(); 87 if (0 == fPendingExecutions) { 88 static_cast<const DERIVED*>(this)->addPendingIOs(); 89 } 90 ++fPendingExecutions; 91 this->validate(); 92 } 93 94 void completedExecution() const { 95 this->validate(); 96 --fPendingExecutions; 97 if (0 == fPendingExecutions) { 98 if (0 == fRefCnt) { 99 delete this; 100 return; 101 } else { 102 static_cast<const DERIVED*>(this)->pendingIOComplete(); 103 } 104 } 105 this->validate(); 106 } 107 108 private: 109 /** This will be called when the ref cnt is zero. The object may or may not have pending 110 executions. */ 111 virtual void notifyRefCntIsZero() const = 0; 112 113 mutable int32_t fRefCnt; 114 // Count of deferred executions not yet issued to the 3D API. 115 mutable int32_t fPendingExecutions; 116 117 // Only this class can access addPendingExecution() and completedExecution(). 118 template <typename T> friend class GrPendingProgramElement; 119 friend class GrProcessorSet; 120 121 typedef SkNoncopyable INHERITED; 122 }; 123 124 #endif 125