Struct wasmer_vm::InstanceHandle

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pub struct InstanceHandle { /* private fields */ }

Expand description

A handle holding an Instance of a WebAssembly module.

This is more or less a public facade of the private Instance, providing useful higher-level API.

Implementations

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impl InstanceHandle

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pub unsafe fn new(
 allocator: InstanceAllocator,
 module: Arc<ModuleInfo>,
 context: &mut StoreObjects,
 finished_functions: BoxedSlice<LocalFunctionIndex, FunctionBodyPtr>,
 finished_function_call_trampolines: BoxedSlice<SignatureIndex, VMTrampoline>,
 finished_memories: BoxedSlice<LocalMemoryIndex, InternalStoreHandle<VMMemory>>,
 finished_tables: BoxedSlice<LocalTableIndex, InternalStoreHandle<VMTable>>,
 finished_globals: BoxedSlice<LocalGlobalIndex, InternalStoreHandle<VMGlobal>>,
 imports: Imports,
 vmshared_signatures: BoxedSlice<SignatureIndex, VMSharedSignatureIndex>
) -> Result<Self, Trap>

Create a new InstanceHandle pointing at a new [InstanceRef].

This method is not necessarily inherently unsafe to call, but in general the APIs of an Instance are quite unsafe and have not been really audited for safety that much. As a result the unsafety here on this method is a low-overhead way of saying “this is an extremely unsafe type to work with”.

Extreme care must be taken when working with InstanceHandle and it’s recommended to have relatively intimate knowledge of how it works internally if you’d like to do so. If possible it’s recommended to use the wasmer crate API rather than this type since that is vetted for safety.

However the following must be taken care of before calling this function:

The memory at instance.tables_ptr() must be initialized with data for all the local tables.
The memory at instance.memories_ptr() must be initialized with data for all the local memories.

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pub unsafe fn finish_instantiation(
 &mut self,
 trap_handler: Option<*const TrapHandlerFn<'static>>,
 data_initializers: &[DataInitializer<'_>]
) -> Result<(), Trap>

Finishes the instantiation process started by Instance::new.

Safety

Only safe to call immediately after instantiation.

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pub fn vmctx(&self) -> &VMContext

Return a reference to the vmctx used by compiled wasm code.

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pub fn vmctx_ptr(&self) -> *mut VMContext

Return a raw pointer to the vmctx used by compiled wasm code.

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pub fn vmoffsets(&self) -> &VMOffsets

Return a reference to the VMOffsets to get offsets in the Self::vmctx_ptr region. Be careful when doing pointer arithmetic!

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pub fn module(&self) -> &Arc<ModuleInfo>

Return a reference-counting pointer to a module.

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pub fn module_ref(&self) -> &ModuleInfo

Return a reference to a module.

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pub fn lookup(&mut self, field: &str) -> Option<VMExtern>

Lookup an export with the given name.

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pub fn lookup_by_declaration(&mut self, export: ExportIndex) -> VMExtern

Lookup an export with the given export declaration.

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pub fn exports(&self) -> Iter<'_, String, ExportIndex>

Return an iterator over the exports of this instance.

Specifically, it provides access to the key-value pairs, where the keys are export names, and the values are export declarations which can be resolved lookup_by_declaration.

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