Struct CreateParams 

pub struct CreateParams { /* private fields */ }

Initial configuration parameters for a new Isolate.

Implementations

impl CreateParams

pub fn counter_lookup_callback( self, callback: unsafe extern "C" fn(name: *const char) -> *mut i32, ) -> Self

Enables the host application to provide a mechanism for recording statistics counters.

pub fn snapshot_blob(self, data: StartupData) -> Self

Explicitly specify a startup snapshot blob.

pub fn array_buffer_allocator( self, array_buffer_allocator: impl Into<SharedPtr<ArrayBufferAllocator>>, ) -> Self

The ArrayBuffer::ArrayBufferAllocator to use for allocating and freeing the backing store of ArrayBuffers.

pub fn has_set_array_buffer_allocator(&self) -> bool

Check if array_buffer_allocator has already been called. Useful to some embedders that might want to set an allocator but not overwrite if one was already set by a user.

pub fn external_references( self, ext_refs: Cow<'static, [ExternalReference]>, ) -> Self

Specifies an optional nullptr-terminated array of raw addresses in the embedder that V8 can match against during serialization and use for deserialization. This array and its content must stay valid for the entire lifetime of the isolate.

pub fn allow_atomics_wait(self, value: bool) -> Self

Whether calling Atomics.wait (a function that may block) is allowed in this isolate. This can also be configured via SetAllowAtomicsWait.

pub fn heap_limits(self, initial: usize, max: usize) -> Self

Configures the constraints with reasonable default values based on the provided lower and upper bounds.

By default V8 starts with a small heap and dynamically grows it to match the set of live objects. This may lead to ineffective garbage collections at startup if the live set is large. Setting the initial heap size avoids such garbage collections. Note that this does not affect young generation garbage collections.

When the heap size approaches max, V8 will perform series of garbage collections and invoke the NearHeapLimitCallback. If the garbage collections do not help and the callback does not increase the limit, then V8 will crash with V8::FatalProcessOutOfMemory.

The heap size includes both the young and the old generation.

Arguments

• initial - The initial heap size or zero in bytes
• max - The hard limit for the heap size in bytes

pub fn heap_limits_from_system_memory( self, physical_memory: u64, virtual_memory_limit: u64, ) -> Self

Configures the constraints with reasonable default values based on the capabilities of the current device the VM is running on.

By default V8 starts with a small heap and dynamically grows it to match the set of live objects. This may lead to ineffective garbage collections at startup if the live set is large. Setting the initial heap size avoids such garbage collections. Note that this does not affect young generation garbage collections.

When the heap size approaches its maximum, V8 will perform series of garbage collections and invoke the NearHeapLimitCallback. If the garbage collections do not help and the callback does not increase the limit, then V8 will crash with V8::FatalProcessOutOfMemory.

Arguments

• physical_memory - The total amount of physical memory on the current device, in bytes.
• virtual_memory_limit - The amount of virtual memory on the current device, in bytes, or zero, if there is no limit.

pub fn max_old_generation_size_in_bytes(&self) -> usize

Returns the maximum size of the old generation in bytes.

pub fn set_max_old_generation_size_in_bytes(self, limit: usize) -> Self

Sets the maximum size of the old generation in bytes. When the old generation approaches this limit, V8 will perform series of garbage collections and invoke the NearHeapLimitCallback.

pub fn max_young_generation_size_in_bytes(&self) -> usize

Returns the maximum size of the young generation in bytes.

pub fn set_max_young_generation_size_in_bytes(self, limit: usize) -> Self

Sets the maximum size of the young generation in bytes. The young generation consists of two semi-spaces and a large object space. This affects frequency of Scavenge garbage collections.

pub fn code_range_size_in_bytes(&self) -> usize

Returns the code range size in bytes.

pub fn set_code_range_size_in_bytes(self, limit: usize) -> Self

Sets the amount of virtual memory reserved for generated code in bytes. This is relevant for 64-bit architectures that rely on code range for calls in code.

pub fn stack_limit(&self) -> *mut u32

Returns the stack limit (the address beyond which the VM’s stack may not grow), or null if not set.

pub unsafe fn set_stack_limit(self, value: *mut u32) -> Self

Sets the address beyond which the VM’s stack may not grow.

Safety

The caller must ensure that the pointer remains valid for the lifetime of the isolate, and points to a valid stack boundary.

pub fn initial_old_generation_size_in_bytes(&self) -> usize

Returns the initial size of the old generation in bytes.

pub fn set_initial_old_generation_size_in_bytes( self, initial_size: usize, ) -> Self

Sets the initial size of the old generation in bytes. Setting the initial size avoids ineffective garbage collections at startup if the live set is large.

pub fn initial_young_generation_size_in_bytes(&self) -> usize

Returns the initial size of the young generation in bytes.

pub fn set_initial_young_generation_size_in_bytes( self, initial_size: usize, ) -> Self

Sets the initial size of the young generation in bytes.

pub fn cpp_heap(self, heap: UniqueRef<Heap>) -> Self

A CppHeap used to construct the Isolate. V8 takes ownership of the CppHeap passed this way.

Trait Implementations

impl Debug for CreateParams

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for CreateParams

fn default() -> CreateParams

Returns the “default value” for a type.