gecko-dev/js/public/Initialization.h

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/* SpiderMonkey initialization and shutdown APIs. */
#ifndef js_Initialization_h
#define js_Initialization_h
#include "jstypes.h"
namespace JS {
namespace detail {
enum class InitState {
Uninitialized = 0,
Initializing,
Running,
ShutDown
};
/**
* SpiderMonkey's initialization status is tracked here, and it controls things
* that should happen only once across all runtimes. It's an API requirement
* that JS_Init (and JS_ShutDown, if called) be called in a thread-aware
* manner, so this (internal -- embedders, don't use!) variable doesn't need to
* be atomic.
*/
extern JS_PUBLIC_DATA(InitState)
libraryInitState;
extern JS_PUBLIC_API(const char*)
InitWithFailureDiagnostic(bool isDebugBuild);
} // namespace detail
} // namespace JS
// These are equivalent to ICU's |UMemAllocFn|, |UMemReallocFn|, and
// |UMemFreeFn| types. The first argument (called |context| in the ICU docs)
// will always be nullptr and should be ignored.
typedef void* (*JS_ICUAllocFn)(const void*, size_t size);
typedef void* (*JS_ICUReallocFn)(const void*, void* p, size_t size);
typedef void (*JS_ICUFreeFn)(const void*, void* p);
/**
* This function can be used to track memory used by ICU. If it is called, it
* *must* be called before JS_Init. Don't use it unless you know what you're
* doing!
*/
extern JS_PUBLIC_API(bool)
JS_SetICUMemoryFunctions(JS_ICUAllocFn allocFn,
JS_ICUReallocFn reallocFn,
JS_ICUFreeFn freeFn);
#ifdef ENABLE_BIGINT
namespace JS {
// These types are documented as allocate_function, reallocate_function,
// and free_function in the Info node `(gmp)Custom Allocation`.
using GMPAllocFn = void* (*)(size_t allocSize);
using GMPReallocFn = void* (*)(void* p, size_t oldSize, size_t newSize);
using GMPFreeFn = void (*)(void* p, size_t size);
// This function can be used to track memory used by GMP. If it is
// called, it *must* be called before JS_Init so that same functions are
// used for all allocations.
extern JS_PUBLIC_API(void)
SetGMPMemoryFunctions(GMPAllocFn allocFn,
GMPReallocFn reallocFn,
GMPFreeFn freeFn);
}; // namespace JS
#endif
/**
* Initialize SpiderMonkey, returning true only if initialization succeeded.
* Once this method has succeeded, it is safe to call JS_NewContext and other
* JSAPI methods.
*
* This method must be called before any other JSAPI method is used on any
* thread. Once it has been used, it is safe to call any JSAPI method, and it
* remains safe to do so until JS_ShutDown is correctly called.
*
* It is currently not possible to initialize SpiderMonkey multiple times (that
* is, calling JS_Init/JSAPI methods/JS_ShutDown in that order, then doing so
* again). This restriction may eventually be lifted.
*/
inline bool
JS_Init(void)
{
#ifdef DEBUG
return !JS::detail::InitWithFailureDiagnostic(true);
#else
return !JS::detail::InitWithFailureDiagnostic(false);
#endif
}
/**
* A variant of JS_Init. On success it returns nullptr. On failure it returns a
* pointer to a string literal that describes how initialization failed, which
* can be useful for debugging purposes.
*/
inline const char*
JS_InitWithFailureDiagnostic(void)
{
#ifdef DEBUG
return JS::detail::InitWithFailureDiagnostic(true);
#else
return JS::detail::InitWithFailureDiagnostic(false);
#endif
}
/*
* Returns true if SpiderMonkey has been initialized successfully, even if it has
* possibly been shut down.
*
* Note that it is the responsibility of the embedder to call JS_Init() and
* JS_ShutDown() at the correct times, and therefore this API should ideally not
* be necessary to use. This is only intended to be used in cases where the
* embedder isn't in full control of deciding whether to initialize SpiderMonkey
* or hand off the task to another consumer.
*/
inline bool
JS_IsInitialized(void)
{
return JS::detail::libraryInitState >= JS::detail::InitState::Running;
}
/**
* Destroy free-standing resources allocated by SpiderMonkey, not associated
* with any runtime, context, or other structure.
*
* This method should be called after all other JSAPI data has been properly
* cleaned up: every new runtime must have been destroyed, every new context
* must have been destroyed, and so on. Calling this method before all other
* resources have been destroyed has undefined behavior.
*
* Failure to call this method, at present, has no adverse effects other than
* leaking memory. This may not always be the case; it's recommended that all
* embedders call this method when all other JSAPI operations have completed.
*
* It is currently not possible to initialize SpiderMonkey multiple times (that
* is, calling JS_Init/JSAPI methods/JS_ShutDown in that order, then doing so
* again). This restriction may eventually be lifted.
*/
extern JS_PUBLIC_API(void)
JS_ShutDown(void);
#endif /* js_Initialization_h */