Differential D4816 Diff 21021 source/scriptinterface/ScriptContext.h

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source/scriptinterface/ScriptContext.h

	/* Copyright (C) 2021 Wildfire Games.			/* Copyright (C) 2022 Wildfire Games.
	* This file is part of 0 A.D.			* This file is part of 0 A.D.
	*			*
	* 0 A.D. is free software: you can redistribute it and/or modify			* 0 A.D. is free software: you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by			* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation, either version 2 of the License, or			* the Free Software Foundation, either version 2 of the License, or
	* (at your option) any later version.			* (at your option) any later version.
	*			*
	* 0 A.D. is distributed in the hope that it will be useful,			* 0 A.D. is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of			* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.			* GNU General Public License for more details.
	*			*
	* You should have received a copy of the GNU General Public License			* You should have received a copy of the GNU General Public License
	* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.			* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
	*/			*/

	#ifndef INCLUDED_SCRIPTCONTEXT			#ifndef INCLUDED_SCRIPTCONTEXT
	#define INCLUDED_SCRIPTCONTEXT			#define INCLUDED_SCRIPTCONTEXT

	#include "ScriptTypes.h"			#include "ScriptTypes.h"
	#include "ScriptExtraHeaders.h"			#include "ScriptExtraHeaders.h"

	#include <list>			#include <list>
				#include <memory>

	// Those are minimal defaults. The runtime for the main game is larger and GCs upon a larger growth.			// Those are minimal defaults. The runtime for the main game is larger and GCs upon a larger growth.
	constexpr int DEFAULT_CONTEXT_SIZE = 16 * 1024 * 1024;			constexpr u32 DEFAULT_CONTEXT_SIZE = 16 * 1024 * 1024;
	constexpr int DEFAULT_HEAP_GROWTH_BYTES_GCTRIGGER = 2 * 1024 * 1024;			constexpr u32 DEFAULT_HEAP_GROWTH_BYTES_GCTRIGGER = 2 * 1024 * 1024;

	/**			/**
	* Abstraction around a SpiderMonkey JSContext.			* Abstraction around a SpiderMonkey JSContext.
	*			*
	* A single ScriptContext, with the associated context,			* A single ScriptContext, with the associated context,
	* should only be used on a single thread.			* should only be used on a single thread.
	*			*
	* (One means to share data between threads and contexts is to create			* (One means to share data between threads and contexts is to create
	* a Script::StructuredClone.)			* a Script::StructuredClone.)
	*/			*/

	class ScriptContext			class ScriptContext
	{			{
	public:			public:
	ScriptContext(int contextSize, int heapGrowthBytesGCTrigger);			ScriptContext(u32 contextSize, u32 heapGrowthBytesGCTrigger);
	~ScriptContext();			~ScriptContext();

	/**			/**
	* Returns a context, in which any number of ScriptInterfaces compartments can live.			* Returns a context, in which any number of ScriptInterfaces compartments can live.
	* Each context should only ever be used on a single thread.			* Each context should only ever be used on a single thread.
	* @param parentContext Parent context from the parent thread, with which we share some thread-safe data			* @param parentContext Parent context from the parent thread, with which we share some thread-safe data
	* @param contextSize Maximum size in bytes of the new context			* @param contextSize Maximum size in bytes of the new context
	* @param heapGrowthBytesGCTrigger Size in bytes of cumulated allocations after which a GC will be triggered			* @param heapGrowthBytesGCTrigger Size in bytes of cumulated allocations after which a GC will be triggered
	*/			*/
	static std::shared_ptr<ScriptContext> CreateContext(			static std::shared_ptr<ScriptContext> CreateContext(
	int contextSize = DEFAULT_CONTEXT_SIZE,			u32 contextSize = DEFAULT_CONTEXT_SIZE,
	int heapGrowthBytesGCTrigger = DEFAULT_HEAP_GROWTH_BYTES_GCTRIGGER);			u32 heapGrowthBytesGCTrigger = DEFAULT_HEAP_GROWTH_BYTES_GCTRIGGER);


	/**			/**
	* MaybeIncrementalGC tries to determine whether a context-wide garbage collection would free up enough memory to			* MaybeIncrementalGC tries to determine whether a context-wide garbage collection would free up enough memory to
	* be worth the amount of time it would take. It does this with our own logic and NOT some predefined JSAPI logic because			* be worth the amount of time it would take. It does this with our own logic and NOT some predefined JSAPI logic because
	* such functionality currently isn't available out of the box.			* such functionality currently isn't available out of the box.
	* It does incremental GC which means it will collect one slice each time it's called until the garbage collection is done.			* It does incremental GC which means it will collect one slice each time it's called until the garbage collection is done.
	* This can and should be called quite regularly. The delay parameter allows you to specify a minimum time since the last GC			* This can and should be called quite regularly. The timeBudget paramater specifies the maximum time the GC is allowed to run.
	* in seconds (the delay should be a fraction of a second in most cases though).			*/
	* It will only start a new incremental GC or another GC slice if this time is exceeded. The user of this function is			void MaybeIncrementalGC(double timeBudgetMilliseconds);
	* responsible for ensuring that GC can run with a small enough delay to get done with the work.			/**
				* ShrinkingGC runs a full stop-the-world GC. Used only in testing.
	*/			*/
	void MaybeIncrementalGC(double delay);
	void ShrinkingGC();			void ShrinkingGC();

	/**			/**
	* This is used to keep track of realms which should be prepared for a GC.			* This is used to keep track of realms which should be prepared for a GC.
	*/			*/
	void RegisterRealm(JS::Realm* realm);			void RegisterRealm(JS::Realm* realm);
	void UnRegisterRealm(JS::Realm* realm);			void UnRegisterRealm(JS::Realm* realm);

	/**			/**
	* GetGeneralJSContext returns the context without starting a GC request and without			* GetGeneralJSContext returns the context without starting a GC request and without
	* entering any compartment. It should only be used in specific situations, such as			* entering any compartment. It should only be used in specific situations, such as
	* creating a new compartment, or when initializing a persistent rooted.			* creating a new compartment, or when initializing a persistent rooted.
	* If you need the compartmented context of a ScriptInterface, you should create a			* If you need the compartmented context of a ScriptInterface, you should create a
	* ScriptRequest and use the context from that.			* ScriptRequest and use the context from that.
	*/			*/
	JSContext* GetGeneralJSContext() const { return m_cx; }			JSContext* GetGeneralJSContext() const { return m_cx; }

	private:			private:

	JSContext* m_cx;			JSContext* m_cx;

	void PrepareZonesForIncrementalGC() const;			void PrepareZonesForIncrementalGC() const;
	std::list<JS::Realm*> m_Realms;			std::list<JS::Realm*> m_Realms;

	int m_ContextSize;			u32 m_HeapGrowthBytesGCTrigger;
	int m_HeapGrowthBytesGCTrigger;			u32 m_LastGCBytes;
	int m_LastGCBytes;
	double m_LastGCCheck;
	};			};

	// Using a global object for the context is a workaround until Simulation, AI, etc,			// Using a global object for the context is a workaround until Simulation, AI, etc,
	// use their own threads and also their own contexts.			// use their own threads and also their own contexts.
	extern thread_local std::shared_ptr<ScriptContext> g_ScriptContext;			extern thread_local std::shared_ptr<ScriptContext> g_ScriptContext;

	#endif // INCLUDED_SCRIPTCONTEXT			#endif // INCLUDED_SCRIPTCONTEXT