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wasmtime/crates/c-api/include/wasmtime/instance.h
Alex Crichton 7a1b7cdf92 Implement RFC 11: Redesigning Wasmtime's APIs (#2897)
Implement Wasmtime's new API as designed by RFC 11. This is quite a large commit which has had lots of discussion externally, so for more information it's best to read the RFC thread and the PR thread.
2021-06-03 09:10:53 -05:00

159 lines
5.1 KiB
C

/**
* \file wasmtime/instance.h
*
* Wasmtime APIs for interacting with wasm instances.
*/
#ifndef WASMTIME_INSTANCE_H
#define WASMTIME_INSTANCE_H
#include <wasm.h>
#include <wasmtime/extern.h>
#include <wasmtime/module.h>
#include <wasmtime/store.h>
#ifdef __cplusplus
extern "C" {
#endif
/**
* \brief An opaque object representing the type of an instance.
*/
typedef struct wasmtime_instancetype wasmtime_instancetype_t;
/// \brief Deletes an instance type
WASM_API_EXTERN void wasmtime_instancetype_delete(wasmtime_instancetype_t *ty);
/**
* \brief Returns the list of exports that this instance type provides.
*
* This function does not take ownership of the provided instance type but
* ownership of `out` is passed to the caller. Note that `out` is treated as
* uninitialized when passed to this function.
*/
WASM_API_EXTERN void wasmtime_instancetype_exports(const wasmtime_instancetype_t*, wasm_exporttype_vec_t* out);
/**
* \brief Converts a #wasmtime_instancetype_t to a #wasm_externtype_t
*
* The returned value is owned by the #wasmtime_instancetype_t argument and should not
* be deleted.
*/
WASM_API_EXTERN wasm_externtype_t* wasmtime_instancetype_as_externtype(wasmtime_instancetype_t*);
/**
* \brief Attempts to convert a #wasm_externtype_t to a #wasmtime_instancetype_t
*
* The returned value is owned by the #wasmtime_instancetype_t argument and should not
* be deleted. Returns `NULL` if the provided argument is not a
* #wasmtime_instancetype_t.
*/
WASM_API_EXTERN wasmtime_instancetype_t* wasmtime_externtype_as_instancetype(wasm_externtype_t*);
/**
* \brief Instantiate a wasm module.
*
* This function will instantiate a WebAssembly module with the provided
* imports, creating a WebAssembly instance. The returned instance can then
* afterwards be inspected for exports.
*
* \param store the store in which to create the instance
* \param module the module that's being instantiated
* \param imports the imports provided to the module
* \param nimports the size of `imports`
* \param instance where to store the returned instance
* \param trap where to store the returned trap
*
* This function requires that `imports` is the same size as the imports that
* `module` has. Additionally the `imports` array must be 1:1 lined up with the
* imports of the `module` specified. This is intended to be relatively low
* level, and #wasmtime_linker_instantiate is provided for a more ergonomic
* name-based resolution API.
*
* The states of return values from this function are similar to
* #wasmtime_func_call where an error can be returned meaning something like a
* link error in this context. A trap can be returned (meaning no error or
* instance is returned), or an instance can be returned (meaning no error or
* trap is returned).
*
* Note that this function requires that all `imports` specified must be owned
* by the `store` provided as well.
*
* This function does not take ownership of any of its arguments, but all return
* values are owned by the caller.
*/
WASM_API_EXTERN wasmtime_error_t *wasmtime_instance_new(
wasmtime_context_t *store,
const wasmtime_module_t *module,
const wasmtime_extern_t* imports,
size_t nimports,
wasmtime_instance_t *instance,
wasm_trap_t **trap
);
/**
* \brief Returns the type of the specified instance.
*
* The returned type is owned by the caller.
*/
WASM_API_EXTERN wasmtime_instancetype_t *wasmtime_instance_type(
const wasmtime_context_t *store,
const wasmtime_instance_t *instance
);
/**
* \brief Get an export by name from an instance.
*
* \param store the store that owns `instance`
* \param instance the instance to lookup within
* \param name the export name to lookup
* \param name_len the byte length of `name`
* \param item where to store the returned value
*
* Returns nonzero if the export was found, and `item` is filled in. Otherwise
* returns 0.
*
* Doesn't take ownership of any arguments but does return ownership of the
* #wasmtime_extern_t.
*/
WASM_API_EXTERN bool wasmtime_instance_export_get(
wasmtime_context_t *store,
const wasmtime_instance_t *instance,
const char *name,
size_t name_len,
wasmtime_extern_t *item
);
/**
* \brief Get an export by index from an instance.
*
* \param store the store that owns `instance`
* \param instance the instance to lookup within
* \param index the index to lookup
* \param name where to store the name of the export
* \param name_len where to store the byte length of the name
* \param item where to store the export itself
*
* Returns nonzero if the export was found, and `name`, `name_len`, and `item`
* are filled in. Otherwise returns 0.
*
* Doesn't take ownership of any arguments but does return ownership of the
* #wasmtime_extern_t. The `name` pointer return value is owned by the `store`
* and must be immediately used before calling any other APIs on
* #wasmtime_context_t.
*/
WASM_API_EXTERN bool wasmtime_instance_export_nth(
wasmtime_context_t *store,
const wasmtime_instance_t *instance,
size_t index,
char **name,
size_t *name_len,
wasmtime_extern_t *item
);
#ifdef __cplusplus
} // extern "C"
#endif
#endif // WASMTIME_INSTANCE_H