v8  7.0.276 (node 11.14.0)
V8 is Google's open source JavaScript engine
Public Types | Public Member Functions | Static Protected Member Functions
Platform Class Referenceabstract

#include <v8-platform.h>

Public Types

typedef void(* StackTracePrinter) ()
 

Public Member Functions

virtual ~Platform ()=default
 
virtual PageAllocator * GetPageAllocator ()
 
virtual void OnCriticalMemoryPressure ()
 
virtual bool OnCriticalMemoryPressure (size_t length)
 
virtual int NumberOfWorkerThreads ()=0
 
virtual std::shared_ptr< v8::TaskRunner > GetForegroundTaskRunner (Isolate *isolate)=0
 
virtual void CallOnWorkerThread (std::unique_ptr< Task > task)=0
 
virtual void CallBlockingTaskOnWorkerThread (std::unique_ptr< Task > task)
 
virtual void CallDelayedOnWorkerThread (std::unique_ptr< Task > task, double delay_in_seconds)=0
 
virtual void CallOnForegroundThread (Isolate *isolate, Task *task)=0
 
virtual void CallDelayedOnForegroundThread (Isolate *isolate, Task *task, double delay_in_seconds)=0
 
virtual void CallIdleOnForegroundThread (Isolate *isolate, IdleTask *task)
 
virtual bool IdleTasksEnabled (Isolate *isolate)
 
virtual double MonotonicallyIncreasingTime ()=0
 
virtual double CurrentClockTimeMillis ()=0
 
virtual StackTracePrinter GetStackTracePrinter ()
 
virtual TracingController * GetTracingController ()=0
 

Static Protected Member Functions

static double SystemClockTimeMillis ()
 

Detailed Description

V8 Platform abstraction layer.

The embedder has to provide an implementation of this interface before initializing the rest of V8.

Definition at line 247 of file v8-platform.h.

Member Typedef Documentation

◆ StackTracePrinter

typedef void(* StackTracePrinter) ()

Definition at line 371 of file v8-platform.h.

Constructor & Destructor Documentation

◆ ~Platform()

virtual ~Platform ( )
virtualdefault

Member Function Documentation

◆ CallBlockingTaskOnWorkerThread()

virtual void CallBlockingTaskOnWorkerThread ( std::unique_ptr< Task >  task)
inlinevirtual

Schedules a task that blocks the main thread to be invoked with high-priority on a worker thread.

Definition at line 307 of file v8-platform.h.

References Platform::CallOnWorkerThread().

◆ CallDelayedOnForegroundThread()

virtual void CallDelayedOnForegroundThread ( Isolate *  isolate,
Task *  task,
double  delay_in_seconds 
)
pure virtual

Schedules a task to be invoked on a foreground thread wrt a specific |isolate| after the given number of seconds |delay_in_seconds|. Tasks posted for the same isolate should be execute in order of scheduling. The definition of "foreground" is opaque to V8.

◆ CallDelayedOnWorkerThread()

virtual void CallDelayedOnWorkerThread ( std::unique_ptr< Task >  task,
double  delay_in_seconds 
)
pure virtual

Schedules a task to be invoked on a worker thread after |delay_in_seconds| expires.

◆ CallIdleOnForegroundThread()

virtual void CallIdleOnForegroundThread ( Isolate *  isolate,
IdleTask *  task 
)
inlinevirtual

Schedules a task to be invoked on a foreground thread wrt a specific |isolate| when the embedder is idle. Requires that SupportsIdleTasks(isolate) is true. Idle tasks may be reordered relative to other task types and may be starved for an arbitrarily long time if no idle time is available. The definition of "foreground" is opaque to V8.

Definition at line 344 of file v8-platform.h.

◆ CallOnForegroundThread()

virtual void CallOnForegroundThread ( Isolate *  isolate,
Task *  task 
)
pure virtual

Schedules a task to be invoked on a foreground thread wrt a specific |isolate|. Tasks posted for the same isolate should be execute in order of scheduling. The definition of "foreground" is opaque to V8.

◆ CallOnWorkerThread()

virtual void CallOnWorkerThread ( std::unique_ptr< Task >  task)
pure virtual

Schedules a task to be invoked on a worker thread.

Referenced by Platform::CallBlockingTaskOnWorkerThread().

◆ CurrentClockTimeMillis()

virtual double CurrentClockTimeMillis ( )
pure virtual

Current wall-clock time in milliseconds since epoch. This function is expected to return at least millisecond-precision values.

◆ GetForegroundTaskRunner()

virtual std::shared_ptr<v8::TaskRunner> GetForegroundTaskRunner ( Isolate *  isolate)
pure virtual

Returns a TaskRunner which can be used to post a task on the foreground. This function should only be called from a foreground thread.

◆ GetPageAllocator()

virtual PageAllocator* GetPageAllocator ( )
inlinevirtual

Allows the embedder to manage memory page allocations.

Definition at line 254 of file v8-platform.h.

◆ GetStackTracePrinter()

virtual StackTracePrinter GetStackTracePrinter ( )
inlinevirtual

Returns a function pointer that print a stack trace of the current stack on invocation. Disables printing of the stack trace if nullptr.

Definition at line 377 of file v8-platform.h.

◆ GetTracingController()

virtual TracingController* GetTracingController ( )
pure virtual

Returns an instance of a v8::TracingController. This must be non-nullptr.

◆ IdleTasksEnabled()

virtual bool IdleTasksEnabled ( Isolate *  isolate)
inlinevirtual

Returns true if idle tasks are enabled for the given |isolate|.

Definition at line 352 of file v8-platform.h.

◆ MonotonicallyIncreasingTime()

virtual double MonotonicallyIncreasingTime ( )
pure virtual

Monotonically increasing time in seconds from an arbitrary fixed point in the past. This function is expected to return at least millisecond-precision values. For this reason, it is recommended that the fixed point be no further in the past than the epoch.

◆ NumberOfWorkerThreads()

virtual int NumberOfWorkerThreads ( )
pure virtual

Gets the number of worker threads used by Call(BlockingTask)OnWorkerThread(). This can be used to estimate the number of tasks a work package should be split into. A return value of 0 means that there are no worker threads available. Note that a value of 0 won't prohibit V8 from posting tasks using |CallOnWorkerThread|.

◆ OnCriticalMemoryPressure() [1/2]

virtual void OnCriticalMemoryPressure ( )
inlinevirtual

Enables the embedder to respond in cases where V8 can't allocate large blocks of memory. V8 retries the failed allocation once after calling this method. On success, execution continues; otherwise V8 exits with a fatal error. Embedder overrides of this function must NOT call back into V8.

Definition at line 266 of file v8-platform.h.

◆ OnCriticalMemoryPressure() [2/2]

virtual bool OnCriticalMemoryPressure ( size_t  length)
inlinevirtual

Enables the embedder to respond in cases where V8 can't allocate large memory regions. The |length| parameter is the amount of memory needed. Returns true if memory is now available. Returns false if no memory could be made available. V8 will retry allocations until this method returns false.

Embedder overrides of this function must NOT call back into V8.

Definition at line 280 of file v8-platform.h.

◆ SystemClockTimeMillis()

static double SystemClockTimeMillis ( )
staticprotected

Default implementation of current wall-clock time in milliseconds since epoch. Useful for implementing |CurrentClockTimeMillis| if nothing special needed.

The documentation for this class was generated from the following file: