xpcom/base/nsCycleCollector.h

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  37
  38 #ifndef nsCycleCollector_h__
  39 #define nsCycleCollector_h__
  40
  41 // NOTE: If you use header files to define DEBUG_CC, you must do so here
  42 // *and* in nsCycleCollectionParticipant.h
  43 //#define DEBUG_CC
  44
  45 class nsISupports;
  46 class nsCycleCollectionParticipant;
  47 class nsCycleCollectionTraversalCallback;
  48
  49 // An nsCycleCollectionLanguageRuntime is a per-language object that
  50 // implements language-specific aspects of the cycle collection task.
  51
  52 struct nsCycleCollectionLanguageRuntime
  53 {
  54     virtual nsresult BeginCycleCollection(nsCycleCollectionTraversalCallback &cb) = 0;
  55     virtual nsresult FinishCycleCollection() = 0;
  56     virtual nsCycleCollectionParticipant *ToParticipant(void *p) = 0;
  57 #ifdef DEBUG_CC
  58     virtual void PrintAllReferencesTo(void *p) = 0;
  59 #endif
  60 };
  61
  62 nsresult nsCycleCollector_startup();
  63 // Returns the number of collected nodes.
  64 NS_COM PRUint32 nsCycleCollector_collect();
  65 NS_COM PRUint32 nsCycleCollector_suspectedCount();
  66 void nsCycleCollector_shutdown();
  67
  68 // The JS runtime is special, it needs to call cycle collection during its GC.
  69 // If the JS runtime is registered nsCycleCollector_collect will call
  70 // nsCycleCollectionJSRuntime::Collect which will call
  71 // nsCycleCollector_doCollect, else nsCycleCollector_collect will call
  72 // nsCycleCollector_doCollect directly.
  73 struct nsCycleCollectionJSRuntime : public nsCycleCollectionLanguageRuntime
  74 {
  75     /**
  76      * Runs cycle collection and returns whether cycle collection collected
  77      * anything.
  78      */
  79     virtual PRBool Collect() = 0;
  80 };
  81 // Returns PR_TRUE if cycle collection was started.
  82 NS_COM PRBool nsCycleCollector_beginCollection();
  83 // Returns PR_TRUE if some nodes were collected. Should only be called after
  84 // nsCycleCollector_beginCollection() returned PR_TRUE.
  85 NS_COM PRBool nsCycleCollector_finishCollection();
  86
  87 #ifdef DEBUG
  88 NS_COM void nsCycleCollector_DEBUG_shouldBeFreed(nsISupports *n);
  89 NS_COM void nsCycleCollector_DEBUG_wasFreed(nsISupports *n);
  90 #endif
  91
  92 // Helpers for interacting with language-identified scripts
  93
  94 NS_COM void nsCycleCollector_registerRuntime(PRUint32 langID, nsCycleCollectionLanguageRuntime *rt);
  95 NS_COM void nsCycleCollector_forgetRuntime(PRUint32 langID);
  96
  97 #endif // nsCycleCollector_h__