cc/quads/list_container.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CC_QUADS_LIST_CONTAINER_H_
   6 #define CC_QUADS_LIST_CONTAINER_H_
   7
   8 #include "base/macros.h"
   9 #include "base/memory/scoped_ptr.h"
  10 #include "cc/base/cc_export.h"
  11
  12 namespace cc {
  13 class SharedQuadState;
  14 class DrawQuad;
  15
  16 // This class is a container type that handles allocating contiguous memory for
  17 // new elements and traversing through elements with either iterator or reverse
  18 // iterator. Since this container hands out raw pointers of its elements, it is
  19 // very important that this container never reallocate its memory so those raw
  20 // pointer will continue to be valid.  This class is used to contain
  21 // SharedQuadState or DrawQuad. Since the size of each DrawQuad varies, to hold
  22 // DrawQuads, the allocations size of each element in this class is
  23 // kLargestDrawQuad while BaseElementType is DrawQuad.
  24 template <class BaseElementType>
  25 class CC_EXPORT ListContainer {
  26  public:
  27   // BaseElementType is the type of raw pointers this class hands out; however,
  28   // its derived classes might require different memory sizes.
  29   // max_size_for_derived_class the largest memory size required for all the
  30   // derived classes to use for allocation.
  31   explicit ListContainer(size_t max_size_for_derived_class);
  32   // This constructor omits input variable for max_size_for_derived_class. This
  33   // is used when there is no derived classes from BaseElementType we need to
  34   // worry about, and allocation size is just sizeof(BaseElementType).
  35   ListContainer();
  36   // This constructor reserves the requested memory up front so only a single
  37   // allocation is needed.
  38   ListContainer(size_t max_size_for_derived_class,
  39                 size_t num_of_elements_to_reserve_for);
  40
  41   ~ListContainer();
  42
  43   // This class deals only with char* and void*. It does allocation and passing
  44   // out raw pointers, as well as memory deallocation when being destroyed.
  45   class CC_EXPORT ListContainerCharAllocator;
  46
  47   // This class points to a certain position inside memory of
  48   // ListContainerCharAllocator. It is a base class for ListContainer iterators.
  49   struct CC_EXPORT PositionInListContainerCharAllocator {
  50     ListContainerCharAllocator* ptr_to_container;
  51     size_t vector_index;
  52     char* item_iterator;
  53
  54     PositionInListContainerCharAllocator(
  55         const PositionInListContainerCharAllocator& other);
  56
  57     PositionInListContainerCharAllocator(ListContainerCharAllocator* container,
  58                                          size_t vector_ind,
  59                                          char* item_iter);
  60
  61     bool operator==(const PositionInListContainerCharAllocator& other) const;
  62     bool operator!=(const PositionInListContainerCharAllocator& other) const;
  63
  64     PositionInListContainerCharAllocator Increment();
  65     PositionInListContainerCharAllocator ReverseIncrement();
  66   };
  67
  68   // Iterator classes that can be used to access data.
  69   /////////////////////////////////////////////////////////////////
  70   class CC_EXPORT Iterator : public PositionInListContainerCharAllocator {
  71     // This class is only defined to forward iterate through
  72     // ListContainerCharAllocator.
  73    public:
  74     Iterator(ListContainerCharAllocator* container,
  75              size_t vector_ind,
  76              char* item_iter);
  77     ~Iterator();
  78     BaseElementType* operator->() const;
  79     BaseElementType& operator*() const;
  80     Iterator operator++(int unused_post_increment);
  81     Iterator operator++();
  82   };
  83
  84   class CC_EXPORT ConstIterator : public PositionInListContainerCharAllocator {
  85     // This class is only defined to forward iterate through
  86     // ListContainerCharAllocator.
  87    public:
  88     ConstIterator(ListContainerCharAllocator* container,
  89                   size_t vector_ind,
  90                   char* item_iter);
  91     ConstIterator(const Iterator& other);  // NOLINT
  92     ~ConstIterator();
  93     const BaseElementType* operator->() const;
  94     const BaseElementType& operator*() const;
  95     ConstIterator operator++(int unused_post_increment);
  96     ConstIterator operator++();
  97   };
  98
  99   class CC_EXPORT ReverseIterator
 100       : public PositionInListContainerCharAllocator {
 101     // This class is only defined to reverse iterate through
 102     // ListContainerCharAllocator.
 103    public:
 104     ReverseIterator(ListContainerCharAllocator* container,
 105                     size_t vector_ind,
 106                     char* item_iter);
 107     ~ReverseIterator();
 108     BaseElementType* operator->() const;
 109     BaseElementType& operator*() const;
 110     ReverseIterator operator++(int unused_post_increment);
 111     ReverseIterator operator++();
 112   };
 113
 114   class CC_EXPORT ConstReverseIterator
 115       : public PositionInListContainerCharAllocator {
 116     // This class is only defined to reverse iterate through
 117     // ListContainerCharAllocator.
 118    public:
 119     ConstReverseIterator(ListContainerCharAllocator* container,
 120                          size_t vector_ind,
 121                          char* item_iter);
 122     ConstReverseIterator(const ReverseIterator& other);  // NOLINT
 123     ~ConstReverseIterator();
 124     const BaseElementType* operator->() const;
 125     const BaseElementType& operator*() const;
 126     ConstReverseIterator operator++(int unused_post_increment);
 127     ConstReverseIterator operator++();
 128   };
 129
 130   // When called, all raw pointers that have been handed out are no longer
 131   // valid. Use with caution.
 132   // This function does not deallocate memory.
 133   void EraseAndInvalidateAllPointers(Iterator position);
 134
 135   ConstReverseIterator rbegin() const;
 136   ConstReverseIterator rend() const;
 137   ReverseIterator rbegin();
 138   ReverseIterator rend();
 139   ConstIterator begin() const;
 140   ConstIterator end() const;
 141   Iterator begin();
 142   Iterator end();
 143
 144   BaseElementType* front();
 145   BaseElementType* back();
 146   const BaseElementType* front() const;
 147   const BaseElementType* back() const;
 148
 149   // Take in derived element type and construct it at location generated by
 150   // Allocate().
 151   template <typename DerivedElementType>
 152   DerivedElementType* AllocateAndConstruct() {
 153     DerivedElementType* result =
 154         new (Allocate(sizeof(DerivedElementType))) DerivedElementType;
 155     return result;
 156   }
 157
 158   size_t size() const;
 159   bool empty() const;
 160   void clear();
 161
 162   size_t AvailableSizeWithoutAnotherAllocationForTesting() const;
 163
 164  private:
 165   // Hands out memory location for an element at the end of data structure.
 166   BaseElementType* Allocate(size_t size_of_actual_element_in_bytes);
 167
 168   scoped_ptr<ListContainerCharAllocator> data_;
 169
 170   DISALLOW_COPY_AND_ASSIGN(ListContainer);
 171 };
 172
 173 #if !defined(COMPILER_MSVC)
 174 extern template class ListContainer<SharedQuadState>;
 175 extern template class ListContainer<DrawQuad>;
 176 #endif
 177 }  // namespace cc
 178
 179 #endif  // CC_QUADS_LIST_CONTAINER_H_