1 /* 2 * Copyright 2018 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 GrCCSTLList_DEFINED 9 #define GrCCSTLList_DEFINED 10 11 #include "SkArenaAlloc.h" 12 #include "SkNoncopyable.h" 13 #include <new> 14 15 /** 16 * A singly-linked list whose head element is a local class member. This is required by 17 * GrCCDrawPathsOp because the owning opList is unknown at the time of creation, so we can't use its 18 * associated allocator to create the first element. 19 */ 20 template<typename T> class GrCCSTLList : SkNoncopyable { 21 public: 22 template <typename ...Args> GrCCSTLList(Args &&...args)23 GrCCSTLList(Args&&... args) : fHead(std::forward<Args>(args)...) {} 24 ~GrCCSTLList()25 ~GrCCSTLList() { 26 T* draw = fHead.fNext; // fHead will be destructed automatically. 27 while (draw) { 28 T* next = draw->fNext; 29 draw->~T(); 30 draw = next; 31 } 32 } 33 head()34 const T& head() const { return fHead; } head()35 T& head() { return fHead; } 36 append(GrCCSTLList && right,SkArenaAlloc * alloc)37 void append(GrCCSTLList&& right, SkArenaAlloc* alloc) { 38 T* nextTail = (&right.fHead == right.fTail) ? nullptr : right.fTail; 39 T* newRightHead = 40 new (alloc->makeBytesAlignedTo(sizeof(T), alignof(T))) T(std::move(right.fHead)); 41 42 // Finish the move of right.fHead. 43 right.fHead.fNext = nullptr; 44 right.fTail = &right.fHead; 45 46 fTail->fNext = newRightHead; 47 fTail = !nextTail ? newRightHead : nextTail; 48 } 49 50 template<typename U> struct Iter { 51 bool operator!=(const Iter& that) { return fCurr != that.fCurr; } 52 U& operator*() { return *fCurr; } 53 void operator++() { fCurr = fCurr->fNext; } 54 U* fCurr; 55 }; begin()56 Iter<const T> begin() const { return Iter<const T>{&fHead}; } end()57 Iter<const T> end() const { return Iter<const T>{nullptr}; } begin()58 Iter<T> begin() { return Iter<T>{&fHead}; } end()59 Iter<T> end() { return Iter<T>{nullptr}; } 60 61 private: 62 T fHead; 63 T* fTail = &fHead; 64 }; 65 66 #endif 67