source/scriptinterface/ScriptRuntime.h

   1 /* Copyright (C) 2016 Wildfire Games.
   2  * This file is part of 0 A.D.
   3  *
   4  * 0 A.D. is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * 0 A.D. is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #ifndef INCLUDED_SCRIPTRUNTIME
  19 #define INCLUDED_SCRIPTRUNTIME
  20
  21 #include <sstream>
  22
  23 #include "ScriptTypes.h"
  24 #include "ScriptExtraHeaders.h"
  25
  26 #define STACK_CHUNK_SIZE 8192
  27
  28 /**
  29  * Abstraction around a SpiderMonkey JSRuntime.
  30  * Each ScriptRuntime can be used to initialize several ScriptInterface
  31  * contexts which can then share data, but a single ScriptRuntime should
  32  * only be used on a single thread.
  33  *
  34  * (One means to share data between threads and runtimes is to create
  35  * a ScriptInterface::StructuredClone.)
  36  */
  37
  38 class ScriptRuntime
  39 {
  40 public:
  41         ScriptRuntime(shared_ptr<ScriptRuntime> parentRuntime, int runtimeSize, int heapGrowthBytesGCTrigger);
  42         ~ScriptRuntime();
  43
  44         /**
  45          * MaybeIncrementalRuntimeGC tries to determine whether a runtime-wide garbage collection would free up enough memory to
  46          * be worth the amount of time it would take. It does this with our own logic and NOT some predefined JSAPI logic because
  47          * such functionality currently isn't available out of the box.
  48          * It does incremental GC which means it will collect one slice each time it's called until the garbage collection is done.
  49          * This can and should be called quite regularly. The delay parameter allows you to specify a minimum time since the last GC
  50          * in seconds (the delay should be a fraction of a second in most cases though).
  51          * It will only start a new incremental GC or another GC slice if this time is exceeded. The user of this function is
  52          * responsible for ensuring that GC can run with a small enough delay to get done with the work.
  53          */
  54         void MaybeIncrementalGC(double delay);
  55         void ShrinkingGC();
  56
  57         void RegisterContext(JSContext* cx);
  58         void UnRegisterContext(JSContext* cx);
  59
  60         /**
  61          * Registers an object to be freed/finalized by the ScriptRuntime. Freeing is
  62          * guaranteed to happen after the next minor GC has completed, but might also
  63          * happen a bit later. This is only needed in very special situations
  64          * and you should only use it if you know exactly why you need it!
  65          * Specify a deleter for the shared_ptr to free the void pointer correctly
  66          * (by casting to the right type before calling delete for example).
  67          */
  68         void AddDeferredFinalizationObject(const std::shared_ptr<void>& obj);
  69
  70         JSRuntime* m_rt;
  71
  72 private:
  73
  74         void PrepareContextsForIncrementalGC();
  75         void GCCallbackMember();
  76
  77         std::list<JSContext*> m_Contexts;
  78         std::vector<std::shared_ptr<void> > m_FinalizationListObjectIdCache;
  79
  80         int m_RuntimeSize;
  81         int m_HeapGrowthBytesGCTrigger;
  82         int m_LastGCBytes;
  83         double m_LastGCCheck;
  84
  85         static void GCCallback(JSRuntime *rt, JSGCStatus status, void *data);
  86 };
  87
  88 #endif // INCLUDED_SCRIPTRUNTIME