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stageCacheContext.h
1 //
2 // Copyright 2016 Pixar
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24 #ifndef USD_STAGECACHECONTEXT_H
25 #define USD_STAGECACHECONTEXT_H
26 
27 #include "pxr/pxr.h"
28 #include "pxr/usd/usd/api.h"
29 #include "pxr/base/tf/stacked.h"
30 
31 #include <vector>
32 
33 PXR_NAMESPACE_OPEN_SCOPE
34 
35 
36 class UsdStageCache;
37 
38 // Private helper wrapper class, holds a const reference to a stage cache.
39 struct Usd_NonPopulatingStageCacheWrapper {
40  explicit Usd_NonPopulatingStageCacheWrapper(const UsdStageCache &cache)
41  : cache(cache) {}
42  const UsdStageCache &cache;
43 };
44 
45 // Using a template arg for 'cache' in UsdUseButDoNotPopulateCache enforces
46 // lvalue requirement: rvalues will not bind to function template non-const
47 // reference parameters.
48 
53 template <class StageCache>
54 Usd_NonPopulatingStageCacheWrapper
55 UsdUseButDoNotPopulateCache(StageCache &cache) {
56  return Usd_NonPopulatingStageCacheWrapper(cache);
57 }
58 
59 enum UsdStageCacheContextBlockType
60 {
64  UsdBlockStageCaches,
68  UsdBlockStageCachePopulation,
69 
70  Usd_NoBlock
71 };
72 
121 TF_DEFINE_STACKED(UsdStageCacheContext, true, USD_API)
122 {
123 public:
126  : _rwCache(&cache)
127  , _isReadOnlyCache(false)
128  , _blockType(Usd_NoBlock) {}
129 
132  explicit UsdStageCacheContext(Usd_NonPopulatingStageCacheWrapper holder)
133  : _roCache(&holder.cache)
134  , _isReadOnlyCache(true)
135  , _blockType(Usd_NoBlock) {}
136 
139  explicit UsdStageCacheContext(UsdStageCacheContextBlockType blockType)
140  : _blockType(blockType) {}
141 
142 private:
143  friend class UsdStage;
144 
145  static std::vector<const UsdStageCache *> _GetReadOnlyCaches();
146  static std::vector<const UsdStageCache *> _GetReadableCaches();
147  static std::vector<UsdStageCache *> _GetWritableCaches();
148 
149  // A blocking context is encoded with both members variables null.
150  union {
151  UsdStageCache *_rwCache;
152  const UsdStageCache *_roCache;
153  };
154  bool _isReadOnlyCache;
155  UsdStageCacheContextBlockType _blockType;
156 };
157 
158 
159 PXR_NAMESPACE_CLOSE_SCOPE
160 
161 #endif // USD_STAGECACHECONTEXT_H
The outermost container for scene description, which owns and presents composed prims as a scenegraph...
Definition: stage.h:142
UsdStageCacheContext(UsdStageCache &cache)
Bind a cache for calls to UsdStage::Open() to read from and write to.
A context object that lets the UsdStage::Open() API read from or read from and write to a UsdStageCac...
A strongly concurrency safe collection of UsdStageRefPtr s, enabling sharing across multiple clients ...
Definition: stageCache.h:86
UsdStageCacheContext(Usd_NonPopulatingStageCacheWrapper holder)
Bind a cache for calls to UsdStage::Open() to read from.
UsdStageCacheContext(UsdStageCacheContextBlockType blockType)
Disable cache use completely (with UsdBlockStageCaches) or only for writing (with UsdBlockStageCacheW...