[QUEUED scylla next] import wasmtime.hh

[Commit Bot]

From: Piotr Sarna <sa...@scylladb.com>
Committer: Piotr Sarna <sa...@scylladb.com>
Branch: next

import wasmtime.hh

Courtesy of https://github.com/bytecodealliance/wasmtime-cpp .
Taken as is, with a small licensing blurb added on top.

---
diff --git a/NOTICE.txt b/NOTICE.txt
--- a/NOTICE.txt
+++ b/NOTICE.txt
@@ -7,3 +7,5 @@ These files are located in utils/arch/powerpc/crc32-vpmsum. Their license may be
It includes modified code from https://gitbox.apache.org/repos/asf?p=cassandra-dtest.git (owned by The Apache Software Foundation)

It includes modified tests from https://github.com/etcd-io/etcd.git (owned by The etcd Authors)
+
+It includes files from https://github.com/bytecodealliance/wasmtime-cpp (owned by Bytecode Alliance), licensed with Apache License 2.0.
diff --git a/lang/wasmtime.hh b/lang/wasmtime.hh
--- a/lang/wasmtime.hh
+++ b/lang/wasmtime.hh
@@ -0,0 +1,2665 @@
+/**
+ * Downloaded from https://github.com/bytecodealliance/wasmtime-cpp/blob/main/include/wasmtime.hh
+ * License: Apache License 2.0
+ */
+
+/**
+ * \mainpage
+ *
+ * This project is a C++ API for
+ * [Wasmtime](https://github.com/bytecodealliance/wasmtime). Support for the
+ * C++ API is exclusively built on the [C API of
+ * Wasmtime](https://docs.wasmtime.dev/c-api/), so the C++ support for this is
+ * simply a single header file. To use this header file, though, it must be
+ * combined with the header and binary of Wasmtime's C API. Note, though, that
+ * while this header is built on top of the `wasmtime.h` header file you should
+ * only need to use the contents of this header file to interact with Wasmtime.
+ *
+ * Examples can be [found
+ * online](https://github.com/bytecodealliance/wasmtime-cpp/tree/main/examples)
+ * and otherwise be sure to check out the
+ * [README](https://github.com/bytecodealliance/wasmtime-cpp/blob/main/README.md)
+ * for simple usage instructions. Otherwise you can dive right in to the
+ * reference documentation of \ref wasmtime.hh
+ *
+ * \example hello.cc
+ * \example gcd.cc
+ * \example linking.cc
+ * \example memory.cc
+ * \example interrupt.cc
+ * \example externref.cc
+ */
+
+/**
+ * \file wasmtime.hh
+ */
+
+#ifndef WASMTIME_HH
+#define WASMTIME_HH
+
+#include <any>
+#include <initializer_list>
+#include <iostream>
+#include <limits>
+#include <memory>
+#include <optional>
+#include <variant>
+#include <vector>
+#ifdef __cpp_lib_span
+#include <span>
+#endif
+
+#include "wasmtime.h"
+
+namespace wasmtime {
+
+#ifdef __cpp_lib_span
+
+/// \brief Alias to C++20 std::span when it is available
+template <typename T, std::size_t Extent = std::dynamic_extent>
+using Span = std::span<T, Extent>;
+
+#else
+
+/// \brief Means number of elements determined at runtime
+inline constexpr size_t dynamic_extent =
+ std::numeric_limits<std::size_t>::max();
+
+/**
+ * \brief Span class used when c++20 is not available
+ * @tparam T Type of data
+ * @tparam Extent Static size of data refered by Span class
+ */
+template <typename T, std::size_t Extent = dynamic_extent> class Span {
+public:
+ /// \brief Type used to iterate over this span (a raw pointer)
+ using iterator = T *;
+
+ /// \brief Constructor of Span class
+ Span(T *t, std::size_t n) : ptr_{t}, size_{n} {}
+
+ /// \brief Constructor of Span class for containers
+ template <template <typename, typename> class Container>
+ Span(Container<T, std::allocator<T>> &range)
+ : ptr_{range.data()}, size_{range.size()} {}
+
+ /// \brief Returns item by index
+ T &operator[](ptrdiff_t idx) const {
+ return ptr_[idx]; // NOLINT
+ }
+
+ /// \brief Returns pointer to data
+ T *data() const { return ptr_; }
+
+ /// \brief Returns number of data that referred by Span class
+ std::size_t size() const { return size_; }
+
+ /// \brief Returns begin iterator
+ iterator begin() const { return ptr_; }
+
+ /// \brief Returns end iterator
+ iterator end() const {
+ return ptr_ + size_; // NOLINT
+ }
+
+ /// \brief Returns size in bytes
+ std::size_t size_bytes() const { return sizeof(T) * size_; }
+
+private:
+ T *ptr_;
+ std::size_t size_;
+};
+
+#endif
+
+/**
+ * \brief Errors coming from Wasmtime
+ *
+ * This class represents an error that came from Wasmtime and contains a textual
+ * description of the error that occurred.
+ */
+class Error {
+ std::string msg;
+
+public:
+ /// \brief Creates an error from the raw C API representation
+ ///
+ /// Takes ownership of the provided `error`.
+ Error(wasmtime_error_t *error) {
+ wasm_byte_vec_t msg_bytes;
+ wasmtime_error_message(error, &msg_bytes);
+ msg = std::string(msg_bytes.data, msg_bytes.size);
+ wasm_byte_vec_delete(&msg_bytes);
+ wasmtime_error_delete(error);
+ }
+
+ /// \brief Returns the error message associated with this error.
+ std::string_view message() const { return msg; }
+};
+
+/// \brief Used to print an error.
+inline std::ostream &operator<<(std::ostream &os, const Error &e) {
+ os << e.message();
+ return os;
+}
+
+/**
+ * \brief Fallible result type used for Wasmtime.
+ *
+ * This type is used as the return value of many methods in the Wasmtime API.
+ * This behaves similarly to Rust's `Result<T, E>` and will be replaced with a
+ * C++ standard when it exists.
+ */
+template <typename T, typename E = Error> class Result {
+ std::variant<T, E> data;
+
+public:
+ /// \brief Creates a `Result` from its successful value.
+ Result(T t) : data(std::move(t)) {}
+ /// \brief Creates a `Result` from an error value.
+ Result(E e) : data(std::move(e)) {}
+
+ /// \brief Returns `true` if this result is a success, `false` if it's an
+ /// error
+ explicit operator bool() { return data.index() == 0; }
+
+ /// \brief Returns the error, if present, aborts if this is not an error.
+ E &&err() { return std::get<E>(std::move(data)); }
+ /// \brief Returns the error, if present, aborts if this is not an error.
+ const E &&err() const { return std::get<E>(std::move(data)); }
+
+ /// \brief Returns the success, if present, aborts if this is an error.
+ T &&ok() { return std::get<T>(std::move(data)); }
+ /// \brief Returns the success, if present, aborts if this is an error.
+ const T &&ok() const { return std::get<T>(std::move(data)); }
+
+ /// \brief Returns the success, if present, aborts if this is an error.
+ T unwrap() {
+ if (*this) {
+ return this->ok();
+ }
+ std::cerr << "error: " << this->err().message() << "\n";
+ std::abort();
+ }
+};
+
+/// \brief Strategies passed to `Config::strategy`
+enum class Strategy {
+ /// Automatically selects the compilation strategy
+ Auto = WASMTIME_STRATEGY_AUTO,
+ /// Requires Cranelift to be used for compilation
+ Cranelift = WASMTIME_STRATEGY_CRANELIFT,
+ /// Uses lightbeam for compilation (not supported)
+ Lightbeam = WASMTIME_STRATEGY_LIGHTBEAM,
+};
+
+/// \brief Values passed to `Config::cranelift_opt_level`
+enum class OptLevel {
+ /// No extra optimizations performed
+ None = WASMTIME_OPT_LEVEL_NONE,
+ /// Optimize for speed
+ Speed = WASMTIME_OPT_LEVEL_SPEED,
+ /// Optimize for speed and generated code size
+ SpeedAndSize = WASMTIME_OPT_LEVEL_SPEED_AND_SIZE,
+};
+
+/// \brief Values passed to `Config::profiler`
+enum class ProfilingStrategy {
+ /// No profiling enabled
+ None = WASMTIME_PROFILING_STRATEGY_NONE,
+ /// Profiling hooks via perf's jitdump
+ Jitdump = WASMTIME_PROFILING_STRATEGY_JITDUMP,
+ /// Profiling hooks via VTune
+ Vtune = WASMTIME_PROFILING_STRATEGY_VTUNE,
+};
+
+/**
+ * \brief Configuration for Wasmtime.
+ *
+ * This class is used to configure Wasmtime's compilation and various other
+ * settings such as enabled WebAssembly proposals.
+ *
+ * For more information be sure to consult the [rust
+ * documentation](https://docs.wasmtime.dev/api/wasmtime/struct.Config.html).
+ */
+class Config {
+ friend class Engine;
+
+ struct deleter {
+ void operator()(wasm_config_t *p) const { wasm_config_delete(p); }
+ };
+
+ std::unique_ptr<wasm_config_t, deleter> ptr;
+
+public:
+ /// \brief Creates configuration with all the default settings.
+ Config() : ptr(wasm_config_new()) {}
+
+ /// \brief Configures whether dwarf debuginfo is emitted for assisting
+ /// in-process debugging.
+ ///
+ /// https://docs.wasmtime.dev/api/wasmtime/struct.Config.html#method.debug_info
+ void debug_info(bool enable) {
+ wasmtime_config_debug_info_set(ptr.get(), enable);
+ }
+
+ /// \brief Configures whether WebAssembly code can be interrupted.
+ ///
+ /// https://docs.wasmtime.dev/api/wasmtime/struct.Config.html#method.interruptable
+ void interruptable(bool enable) {
+ wasmtime_config_interruptable_set(ptr.get(), enable);
+ }
+
+ /// \brief Configures whether WebAssembly code will consume fuel and trap when
+ /// it runs out.
+ ///
+ /// https://docs.wasmtime.dev/api/wasmtime/struct.Config.html#method.consume_fuel
+ void consume_fuel(bool enable) {
+ wasmtime_config_consume_fuel_set(ptr.get(), enable);
+ }
+
+ /// \brief Configures the maximum amount of native stack wasm can consume.
+ ///
+ /// https://docs.wasmtime.dev/api/wasmtime/struct.Config.html#method.max_wasm_stack
+ void max_wasm_stack(size_t stack) {
+ wasmtime_config_max_wasm_stack_set(ptr.get(), stack);
+ }
+
+ /// \brief Configures whether the WebAssembly threads proposal is enabled
+ ///
+ /// https://docs.wasmtime.dev/api/wasmtime/struct.Config.html#method.wasm_threads
+ void wasm_threads(bool enable) {
+ wasmtime_config_wasm_threads_set(ptr.get(), enable);
+ }
+
+ /// \brief Configures whether the WebAssembly reference types proposal is
+ /// enabled
+ ///
+ /// https://docs.wasmtime.dev/api/wasmtime/struct.Config.html#method.wasm_reference_types
+ void wasm_reference_types(bool enable) {
+ wasmtime_config_wasm_reference_types_set(ptr.get(), enable);
+ }
+
+ /// \brief Configures whether the WebAssembly simd proposal is enabled
+ ///
+ /// https://docs.wasmtime.dev/api/wasmtime/struct.Config.html#method.wasm_simd
+ void wasm_simd(bool enable) {
+ wasmtime_config_wasm_simd_set(ptr.get(), enable);
+ }
+
+ /// \brief Configures whether the WebAssembly bulk memory proposal is enabled
+ ///
+ /// https://docs.wasmtime.dev/api/wasmtime/struct.Config.html#method.wasm_bulk_memory
+ void wasm_bulk_memory(bool enable) {
+ wasmtime_config_wasm_bulk_memory_set(ptr.get(), enable);
+ }
+
+ /// \brief Configures whether the WebAssembly multi value proposal is enabled
+ ///
+ /// https://docs.wasmtime.dev/api/wasmtime/struct.Config.html#method.wasm_multi_value
+ void wasm_multi_value(bool enable) {
+ wasmtime_config_wasm_multi_value_set(ptr.get(), enable);
+ }
+
+ /// \brief Configures whether the WebAssembly module linking proposal is
+ /// enabled
+ ///
+ /// https://docs.wasmtime.dev/api/wasmtime/struct.Config.html#method.wasm_module_linking
+ void wasm_module_linking(bool enable) {
+ wasmtime_config_wasm_module_linking_set(ptr.get(), enable);
+ }
+
+ /// \brief Configures compilation strategy for wasm code.
+ ///
+ /// https://docs.wasmtime.dev/api/wasmtime/struct.Config.html#method.strategy
+ [[nodiscard]] Result<std::monostate> strategy(Strategy strategy) {
+ auto *error = wasmtime_config_strategy_set(
+ ptr.get(), static_cast<wasmtime_strategy_t>(strategy));
+ if (error != nullptr) {
+ return Error(error);
+ }
+ return std::monostate();
+ }
+
+ /// \brief Configures whether cranelift's debug verifier is enabled
+ ///
+ /// https://docs.wasmtime.dev/api/wasmtime/struct.Config.html#method.cranelift_debug_verifier
+ void cranelift_debug_verifier(bool enable) {
+ wasmtime_config_cranelift_debug_verifier_set(ptr.get(), enable);
+ }
+
+ /// \brief Configures cranelift's optimization level
+ ///
+ /// https://docs.wasmtime.dev/api/wasmtime/struct.Config.html#method.cranelift_opt_level
+ void cranelift_opt_level(OptLevel level) {
+ wasmtime_config_cranelift_opt_level_set(
+ ptr.get(), static_cast<wasmtime_opt_level_t>(level));
+ }
+
+ /// \brief Configures an active wasm profiler
+ ///
+ /// https://docs.wasmtime.dev/api/wasmtime/struct.Config.html#method.profiler
+ [[nodiscard]] Result<std::monostate> profiler(ProfilingStrategy profiler) {
+ auto *error = wasmtime_config_profiler_set(
+ ptr.get(), static_cast<wasmtime_profiling_strategy_t>(profiler));
+ if (error != nullptr) {
+ return Error(error);
+ }
+ return std::monostate();
+ }
+
+ /// \brief Configures the maximum size of memory to use a "static memory"
+ ///
+ /// https://docs.wasmtime.dev/api/wasmtime/struct.Config.html#method.static_memory_maximum_size
+ void static_memory_maximum_size(size_t size) {
+ wasmtime_config_static_memory_maximum_size_set(ptr.get(), size);
+ }
+
+ /// \brief Configures the size of static memory's guard region
+ ///
+ /// https://docs.wasmtime.dev/api/wasmtime/struct.Config.html#method.static_memory_guard_size
+ void static_memory_guard_size(size_t size) {
+ wasmtime_config_static_memory_guard_size_set(ptr.get(), size);
+ }
+
+ /// \brief Configures the size of dynamic memory's guard region
+ ///
+ /// https://docs.wasmtime.dev/api/wasmtime/struct.Config.html#method.dynamic_memory_guard_size
+ void dynamic_memory_guard_size(size_t size) {
+ wasmtime_config_dynamic_memory_guard_size_set(ptr.get(), size);
+ }
+
+ /// \brief Loads the default cache configuration present on the system.
+ ///
+ /// https://docs.wasmtime.dev/api/wasmtime/struct.Config.html#method.cache_config_load_default
+ [[nodiscard]] Result<std::monostate> cache_load_default() {
+ auto *error = wasmtime_config_cache_config_load(ptr.get(), nullptr);
+ if (error != nullptr) {
+ return Error(error);
+ }
+ return std::monostate();
+ }
+
+ /// \brief Loads cache configuration from the specified filename.
+ ///
+ /// https://docs.wasmtime.dev/api/wasmtime/struct.Config.html#method.cache_config_load
+ [[nodiscard]] Result<std::monostate> cache_load(const std::string &path) {
+ auto *error = wasmtime_config_cache_config_load(ptr.get(), path.c_str());
+ if (error != nullptr) {
+ return Error(error);
+ }
+ return std::monostate();
+ }
+};
+
+/**
+ * \brief Global compilation state in Wasmtime.
+ *
+ * Created with either default configuration or with a specified instance of
+ * configuration, an `Engine` is used as an umbrella "session" for all other
+ * operations in Wasmtime.
+ */
+class Engine {
+ friend class Store;
+ friend class Module;
+ friend class Linker;
+
+ struct deleter {
+ void operator()(wasm_engine_t *p) const { wasm_engine_delete(p); }
+ };
+
+ std::unique_ptr<wasm_engine_t, deleter> ptr;
+
+public:
+ /// \brief Creates an engine with default compilation settings.
+ Engine() : ptr(wasm_engine_new()) {}
+ /// \brief Creates an engine with the specified compilation settings.
+ explicit Engine(Config config)
+ : ptr(wasm_engine_new_with_config(config.ptr.release())) {}
+};
+
+/**
+ * \brief Converts the WebAssembly text format into the WebAssembly binary
+ * format.
+ *
+ * This will parse the text format and attempt to translate it to the binary
+ * format. Note that the text parser assumes that all WebAssembly features are
+ * enabled and will parse syntax of future proposals. The exact syntax here
+ * parsed may be tweaked over time.
+ *
+ * Returns either an error if parsing failed or the wasm binary.
+ */
+[[nodiscard]] inline Result<std::vector<uint8_t>>
+wat2wasm(std::string_view wat) {
+ wasm_byte_vec_t ret;
+ auto *error = wasmtime_wat2wasm(wat.data(), wat.size(), &ret);
+ if (error != nullptr) {
+ return Error(error);
+ }
+ std::vector<uint8_t> vec;
+ // NOLINTNEXTLINE TODO can this be done without triggering lints?
+ Span<uint8_t> raw(reinterpret_cast<uint8_t *>(ret.data), ret.size);
+ vec.assign(raw.begin(), raw.end());
+ wasm_byte_vec_delete(&ret);
+ return vec;
+}
+
+/**
+ * \brief Min/max limits used for `MemoryType` and `TableType`
+ */
+class Limits {
+ friend class MemoryType;
+ friend class TableType;
+
+ wasm_limits_t raw;
+
+public:
+ /// \brief Configures a minimum limit and no maximum limit.
+ explicit Limits(uint32_t min) : raw{} {
+ raw.min = min;
+ raw.max = wasm_limits_max_default;
+ }
+ /// \brief Configures both a minimum and a maximum limit.
+ Limits(uint32_t min, uint32_t max) : raw{} {
+ raw.min = min;
+ raw.max = max;
+ }
+ /// \brief Creates limits from the raw underlying C API.
+ Limits(const wasm_limits_t *limits) : raw(*limits) {}
+
+ /// \brief Returns the minimum size specified by these limits.
+ uint32_t min() const { return raw.min; }
+
+ /// \brief Returns optional maximum limit configured.
+ std::optional<uint32_t> max() const {
+ if (raw.max == wasm_limits_max_default) {
+ return std::nullopt;
+ }
+ return raw.max;
+ }
+};
+
+/// Different kinds of types accepted by Wasmtime.
+enum class ValKind {
+ /// WebAssembly's `i32` type
+ I32,
+ /// WebAssembly's `i64` type
+ I64,
+ /// WebAssembly's `f32` type
+ F32,
+ /// WebAssembly's `f64` type
+ F64,
+ /// WebAssembly's `v128` type from the simd proposal
+ V128,
+ /// WebAssembly's `externref` type from the reference types
+ ExternRef,
+ /// WebAssembly's `funcref` type from the reference types
+ FuncRef,
+};
+
+/**
+ * \brief Type information about a WebAssembly value.
+ *
+ * Currently mostly just contains the `ValKind`.
+ */
+class ValType {
+ friend class TableType;
+ friend class GlobalType;
+ friend class FuncType;
+
+ struct deleter {
+ void operator()(wasm_valtype_t *p) const { wasm_valtype_delete(p); }
+ };
+
+ std::unique_ptr<wasm_valtype_t, deleter> ptr;
+
+ static wasm_valkind_t kind_to_c(ValKind kind) {
+ switch (kind) {
+ case ValKind::I32:
+ return WASM_I32;
+ case ValKind::I64:
+ return WASM_I64;
+ case ValKind::F32:
+ return WASM_F32;
+ case ValKind::F64:
+ return WASM_F64;
+ case ValKind::ExternRef:
+ return WASM_ANYREF;
+ case ValKind::FuncRef:
+ return WASM_FUNCREF;
+ case ValKind::V128:
+ return WASMTIME_V128;
+ }
+ }
+
+public:
+ /// \brief Non-owning reference to a `ValType`, must not be used after the
+ /// original `ValType` is deleted.
+ class Ref {
+ friend class ValType;
+
+ const wasm_valtype_t *ptr;
+
+ public:
+ /// \brief Instantiates from the raw C API representation.
+ Ref(const wasm_valtype_t *ptr) : ptr(ptr) {}
+ /// Copy constructor
+ Ref(const ValType &ty) : Ref(ty.ptr.get()) {}
+
+ /// \brief Returns the corresponding "kind" for this type.
+ ValKind kind() const {
+ switch (wasm_valtype_kind(ptr)) {
+ case WASM_I32:
+ return ValKind::I32;
+ case WASM_I64:
+ return ValKind::I64;
+ case WASM_F32:
+ return ValKind::F32;
+ case WASM_F64:
+ return ValKind::F64;
+ case WASM_ANYREF:
+ return ValKind::ExternRef;
+ case WASM_FUNCREF:
+ return ValKind::FuncRef;
+ case WASMTIME_V128:
+ return ValKind::V128;
+ }
+ std::abort();
+ }
+ };
+
+ /// \brief Non-owning reference to a list of `ValType` instances. Must not be
+ /// used after the original owner is deleted.
+ class ListRef {
+ const wasm_valtype_vec_t *list;
+
+ public:
+ /// Creates a list from the raw underlying C API.
+ ListRef(const wasm_valtype_vec_t *list) : list(list) {}
+
+ /// This list iterates over a list of `ValType::Ref` instances.
+ typedef const Ref *iterator;
+
+ /// Pointer to the beginning of iteration
+ iterator begin() const {
+ return reinterpret_cast<Ref *>(&list->data[0]); // NOLINT
+ }
+
+ /// Pointer to the end of iteration
+ iterator end() const {
+ return reinterpret_cast<Ref *>(&list->data[list->size]); // NOLINT
+ }
+
+ /// Returns how many types are in this list.
+ size_t size() const { return list->size; }
+ };
+
+private:
+ Ref ref;
+ ValType(wasm_valtype_t *ptr) : ptr(ptr), ref(ptr) {}
+
+public:
+ /// Creates a new type from its kind.
+ ValType(ValKind kind) : ValType(wasm_valtype_new(kind_to_c(kind))) {}
+ /// Copies a `Ref` to a new owned value.
+ ValType(Ref other) : ValType(wasm_valtype_copy(other.ptr)) {}
+ /// Copies one type to a new one.
+ ValType(const ValType &other) : ValType(wasm_valtype_copy(other.ptr.get())) {}
+ /// Copies the contents of another type into this one.
+ ValType &operator=(const ValType &other) {
+ ptr.reset(wasm_valtype_copy(other.ptr.get()));
+ return *this;
+ }
+ ~ValType() = default;
+ /// Moves the memory owned by another value type into this one.
+ ValType(ValType &&other) = default;
+ /// Moves the memory owned by another value type into this one.
+ ValType &operator=(ValType &&other) = default;
+
+ /// \brief Returns the underlying `Ref`, a non-owning reference pointing to
+ /// this instance.
+ Ref *operator->() { return &ref; }
+ /// \brief Returns the underlying `Ref`, a non-owning reference pointing to
+ /// this instance.
+ Ref *operator*() { return &ref; }
+};
+
+/**
+ * \brief Type information about a WebAssembly linear memory
+ */
+class MemoryType {
+ friend class Memory;
+
+ struct deleter {
+ void operator()(wasm_memorytype_t *p) const { wasm_memorytype_delete(p); }
+ };
+
+ std::unique_ptr<wasm_memorytype_t, deleter> ptr;
+
+public:
+ /// \brief Non-owning reference to a `MemoryType`, must not be used after the
+ /// original owner has been deleted.
+ class Ref {
+ friend class MemoryType;
+
+ const wasm_memorytype_t *ptr;
+
+ public:
+ /// Creates a refernece from the raw C API representation.
+ Ref(const wasm_memorytype_t *ptr) : ptr(ptr) {}
+ /// Creates a reference from an original `MemoryType`.
+ Ref(const MemoryType &ty) : Ref(ty.ptr.get()) {}
+
+ /// Returns the underlying limits on this wasm memory type, specified in
+ /// units of wasm pages.
+ Limits limits() const { return Limits(wasm_memorytype_limits(ptr)); }
+ };
+
+private:
+ Ref ref;
+ MemoryType(wasm_memorytype_t *ptr) : ptr(ptr), ref(ptr) {}
+
+public:
+ /// Creates a new wasm memory from the specified limits.
+ explicit MemoryType(const Limits &limits)
+ : MemoryType(wasm_memorytype_new(&limits.raw)) {}
+ /// Creates a new wasm memory type from the specified ref, making a fresh
+ /// owned value.
+ MemoryType(Ref other) : MemoryType(wasm_memorytype_copy(other.ptr)) {}
+ /// Copies the provided type into a new type.
+ MemoryType(const MemoryType &other)
+ : MemoryType(wasm_memorytype_copy(other.ptr.get())) {}
+ /// Copies the provided type into a new type.
+ MemoryType &operator=(const MemoryType &other) {
+ ptr.reset(wasm_memorytype_copy(other.ptr.get()));
+ return *this;
+ }
+ ~MemoryType() = default;
+ /// Moves the type information from another type into this one.
+ MemoryType(MemoryType &&other) = default;
+ /// Moves the type information from another type into this one.
+ MemoryType &operator=(MemoryType &&other) = default;
+
+ /// \brief Returns the underlying `Ref`, a non-owning reference pointing to
+ /// this instance.
+ Ref *operator->() { return &ref; }
+ /// \brief Returns the underlying `Ref`, a non-owning reference pointing to
+ /// this instance.
+ Ref *operator*() { return &ref; }
+};
+
+/**
+ * \brief Type information about a WebAssembly table.
+ */
+class TableType {
+ friend class Table;
+
+ struct deleter {
+ void operator()(wasm_tabletype_t *p) const { wasm_tabletype_delete(p); }
+ };
+
+ std::unique_ptr<wasm_tabletype_t, deleter> ptr;
+
+public:
+ /// Non-owning reference to a `TableType`, must not be used after the original
+ /// owner is deleted.
+ class Ref {
+ friend class TableType;
+
+ const wasm_tabletype_t *ptr;
+
+ public:
+ /// Creates a reference from the raw underlying C API representation.
+ Ref(const wasm_tabletype_t *ptr) : ptr(ptr) {}
+ /// Creates a reference to the provided `TableType`.
+ Ref(const TableType &ty) : Ref(ty.ptr.get()) {}
+
+ /// Returns the limits, in units of elements, of this table.
+ Limits limits() const { return wasm_tabletype_limits(ptr); }
+
+ /// Returns the type of value that is stored in this table.
+ ValType::Ref element() const { return wasm_tabletype_element(ptr); }
+ };
+
+private:
+ Ref ref;
+ TableType(wasm_tabletype_t *ptr) : ptr(ptr), ref(ptr) {}
+
+public:
+ /// Creates a new table type from the specified value type and limits.
+ TableType(ValType ty, Limits limits)
+ : TableType(wasm_tabletype_new(ty.ptr.release(), &limits.raw)) {}
+ /// Clones the given reference into a new table type.
+ TableType(Ref other) : TableType(wasm_tabletype_copy(other.ptr)) {}
+ /// Copies another table type into this one.
+ TableType(const TableType &other)
+ : TableType(wasm_tabletype_copy(other.ptr.get())) {}
+ /// Copies another table type into this one.
+ TableType &operator=(const TableType &other) {
+ ptr.reset(wasm_tabletype_copy(other.ptr.get()));
+ return *this;
+ }
+ ~TableType() = default;
+ /// Moves the table type resources from another type to this one.
+ TableType(TableType &&other) = default;
+ /// Moves the table type resources from another type to this one.
+ TableType &operator=(TableType &&other) = default;
+
+ /// \brief Returns the underlying `Ref`, a non-owning reference pointing to
+ /// this instance.
+ Ref *operator->() { return &ref; }
+ /// \brief Returns the underlying `Ref`, a non-owning reference pointing to
+ /// this instance.
+ Ref *operator*() { return &ref; }
+};
+
+/**
+ * \brief Type information about a WebAssembly global
+ */
+class GlobalType {
+ friend class Global;
+
+ struct deleter {
+ void operator()(wasm_globaltype_t *p) const { wasm_globaltype_delete(p); }
+ };
+
+ std::unique_ptr<wasm_globaltype_t, deleter> ptr;
+
+public:
+ /// Non-owning reference to a `Global`, must not be used after the original
+ /// owner is deleted.
+ class Ref {
+ friend class GlobalType;
+ const wasm_globaltype_t *ptr;
+
+ public:
+ /// Creates a new reference from the raw underlying C API representation.
+ Ref(const wasm_globaltype_t *ptr) : ptr(ptr) {}
+ /// Creates a new reference to the specified type.
+ Ref(const GlobalType &ty) : Ref(ty.ptr.get()) {}
+
+ /// Returns whether or not this global type is mutable.
+ bool is_mutable() const {
+ return wasm_globaltype_mutability(ptr) == WASM_VAR;
+ }
+
+ /// Returns the type of value stored within this global type.
+ ValType::Ref content() const { return wasm_globaltype_content(ptr); }
+ };
+
+private:
+ Ref ref;
+ GlobalType(wasm_globaltype_t *ptr) : ptr(ptr), ref(ptr) {}
+
+public:
+ /// Creates a new global type from the specified value type and mutability.
+ GlobalType(ValType ty, bool mut)
+ : GlobalType(wasm_globaltype_new(
+ ty.ptr.release(),
+ (wasm_mutability_t)(mut ? WASM_VAR : WASM_CONST))) {}
+ /// Clones a reference into a uniquely owned global type.
+ GlobalType(Ref other) : GlobalType(wasm_globaltype_copy(other.ptr)) {}
+ /// Copies othe type information into this one.
+ GlobalType(const GlobalType &other)
+ : GlobalType(wasm_globaltype_copy(other.ptr.get())) {}
+ /// Copies othe type information into this one.
+ GlobalType &operator=(const GlobalType &other) {
+ ptr.reset(wasm_globaltype_copy(other.ptr.get()));
+ return *this;
+ }
+ ~GlobalType() = default;
+ /// Moves the underlying type information from another global into this one.
+ GlobalType(GlobalType &&other) = default;
+ /// Moves the underlying type information from another global into this one.
+ GlobalType &operator=(GlobalType &&other) = default;
+
+ /// \brief Returns the underlying `Ref`, a non-owning reference pointing to
+ /// this instance.
+ Ref *operator->() { return &ref; }
+ /// \brief Returns the underlying `Ref`, a non-owning reference pointing to
+ /// this instance.
+ Ref *operator*() { return &ref; }
+};
+
+/**
+ * \brief Type information for a WebAssembly function.
+ */
+class FuncType {
+ friend class Func;
+
+ struct deleter {
+ void operator()(wasm_functype_t *p) const { wasm_functype_delete(p); }
+ };
+
+ std::unique_ptr<wasm_functype_t, deleter> ptr;
+
+public:
+ /// Non-owning reference to a `FuncType`, must not be used after the original
+ /// owner has been deleted.
+ class Ref {
+ friend class FuncType;
+ const wasm_functype_t *ptr;
+
+ public:
+ /// Creates a new reference from the underlying C API representation.
+ Ref(const wasm_functype_t *ptr) : ptr(ptr) {}
+ /// Creates a new reference to the given type.
+ Ref(const FuncType &ty) : Ref(ty.ptr.get()) {}
+
+ /// Returns the list of types this function type takes as parameters.
+ ValType::ListRef params() const { return wasm_functype_params(ptr); }
+
+ /// Returns the list of types this function type returns.
+ ValType::ListRef results() const { return wasm_functype_results(ptr); }
+ };
+
+private:
+ Ref ref;
+ FuncType(wasm_functype_t *ptr) : ptr(ptr), ref(ptr) {}
+
+public:
+ /// Creates a new function type from the given list of parameters and results.
+ FuncType(std::initializer_list<ValType> params,
+ std::initializer_list<ValType> results)
+ : ref(nullptr) {
+ wasm_valtype_vec_t param_vec;
+ wasm_valtype_vec_t result_vec;
+ wasm_valtype_vec_new_uninitialized(&param_vec, params.size());
+ wasm_valtype_vec_new_uninitialized(&result_vec, results.size());
+ size_t i = 0;
+ for (auto val : params) {
+ param_vec.data[i++] = val.ptr.release(); // NOLINT
+ }
+ i = 0;
+ for (auto val : results) {
+ result_vec.data[i++] = val.ptr.release(); // NOLINT
+ }
+
+ ptr.reset(wasm_functype_new(&param_vec, &result_vec));
+ ref = ptr.get();
+ }
+
+ /// Copies a reference into a uniquely owned function type.
+ FuncType(Ref other) : FuncType(wasm_functype_copy(other.ptr)) {}
+ /// Copies another type's information into this one.
+ FuncType(const FuncType &other)
+ : FuncType(wasm_functype_copy(other.ptr.get())) {}
+ /// Copies another type's information into this one.
+ FuncType &operator=(const FuncType &other) {
+ ptr.reset(wasm_functype_copy(other.ptr.get()));
+ return *this;
+ }
+ ~FuncType() = default;
+ /// Moves type information from anothe type into this one.
+ FuncType(FuncType &&other) = default;
+ /// Moves type information from anothe type into this one.
+ FuncType &operator=(FuncType &&other) = default;
+
+ /// \brief Returns the underlying `Ref`, a non-owning reference pointing to
+ /// this instance.
+ Ref *operator->() { return &ref; }
+ /// \brief Returns the underlying `Ref`, a non-owning reference pointing to
+ /// this instance.
+ Ref *operator*() { return &ref; }
+};
+
+/**
+ * \brief Type information about a WebAssembly import.
+ */
+class ImportType {
+public:
+ /// Non-owning reference to an `ImportType`, must not be used after the
+ /// original owner is deleted.
+ class Ref {
+ friend class TypeList;
+ friend class ExternType;
+
+ const wasm_importtype_t *ptr;
+
+ // TODO: can this circle be broken another way?
+ const wasm_externtype_t *raw_type() { return wasm_importtype_type(ptr); }
+
+ public:
+ /// Creates a new reference from the raw underlying C API representation.
+ Ref(const wasm_importtype_t *ptr) : ptr(ptr) {}
+
+ /// Returns the module name associated with this import.
+ std::string_view module() {
+ const auto *name = wasm_importtype_module(ptr);
+ return std::string_view(name->data, name->size);
+ }
+
+ /// Returns the field name associated with this import.
+ std::string_view name() {
+ const auto *name = wasm_importtype_name(ptr);
+ return std::string_view(name->data, name->size);
+ }
+ };
+
+ /// An owned list of `ImportType` instances.
+ class List {
+ friend class InstanceType;
+ friend class ModuleType;
+
+ wasm_importtype_vec_t list;
+
+ public:
+ /// Creates an empty list
+ List() : list{} {
+ list.size = 0;
+ list.data = nullptr;
+ }
+ List(const List &other) = delete;
+ /// Moves another list into this one.
+ List(List &&other) noexcept : list(other.list) { other.list.size = 0; }
+ ~List() {
+ if (list.size > 0) {
+ wasm_importtype_vec_delete(&list);
+ }
+ }
+
+ List &operator=(const List &other) = delete;
+ /// Moves another list into this one.
+ List &operator=(List &&other) noexcept {
+ std::swap(list, other.list);
+ return *this;
+ }
+
+ /// Iterator type, which is a list of non-owning `ImportType::Ref`
+ /// instances.
+ typedef const Ref *iterator;
+ /// Returns the start of iteration.
+ iterator begin() const {
+ return reinterpret_cast<iterator>(&list.data[0]); // NOLINT
+ }
+ /// Returns the end of iteration.
+ iterator end() const {
+ return reinterpret_cast<iterator>(&list.data[list.size]); // NOLINT
+ }
+ /// Returns the size of this list.
+ size_t size() const { return list.size; }
+ };
+};
+
+/**
+ * \brief Type information about a WebAssembly export
+ */
+class ExportType {
+
+public:
+ /// \brief Non-owning reference to an `ExportType`.
+ ///
+ /// Note to get type information you can use `ExternType::from_export`.
+ class Ref {
+ friend class ExternType;
+
+ const wasm_exporttype_t *ptr;
+
+ const wasm_externtype_t *raw_type() { return wasm_exporttype_type(ptr); }
+
+ public:
+ /// Creates a new reference from the raw underlying C API representation.
+ Ref(const wasm_exporttype_t *ptr) : ptr(ptr) {}
+
+ /// Returns the name of this export.
+ std::string_view name() {
+ const auto *name = wasm_exporttype_name(ptr);
+ return std::string_view(name->data, name->size);
+ }
+ };
+
+ /// An owned list of `ExportType` instances.
+ class List {
+ friend class InstanceType;
+ friend class ModuleType;
+
+ wasm_exporttype_vec_t list;
+
+ public:
+ /// Creates an empty list
+ List() : list{} {
+ list.size = 0;
+ list.data = nullptr;
+ }
+ List(const List &other) = delete;
+ /// Moves another list into this one.
+ List(List &&other) noexcept : list(other.list) { other.list.size = 0; }
+ ~List() {
+ if (list.size > 0) {
+ wasm_exporttype_vec_delete(&list);
+ }
+ }
+
+ List &operator=(const List &other) = delete;
+ /// Moves another list into this one.
+ List &operator=(List &&other) noexcept {
+ std::swap(list, other.list);
+ return *this;
+ }
+
+ /// Iterator type, which is a list of non-owning `ExportType::Ref`
+ /// instances.
+ typedef const Ref *iterator;
+ /// Returns the start of iteration.
+ iterator begin() const {
+ return reinterpret_cast<iterator>(&list.data[0]); // NOLINT
+ }
+ /// Returns the end of iteration.
+ iterator end() const {
+ return reinterpret_cast<iterator>(&list.data[list.size]); // NOLINT
+ }
+ /// Returns the size of this list.
+ size_t size() const { return list.size; }
+ };
+};
+
+/**
+ * \brief Type information about a WebAssembly module.
+ */
+class ModuleType {
+ friend class Module;
+
+ struct deleter {
+ void operator()(wasmtime_moduletype_t *p) const {
+ wasmtime_moduletype_delete(p);
+ }
+ };
+
+ std::unique_ptr<wasmtime_moduletype_t, deleter> ptr;
+
+public:
+ /// Non-owning reference to a `ModuleType`, must not be used after the owner
+ /// has been deleted.
+ class Ref {
+ friend class ModuleType;
+
+ const wasmtime_moduletype_t *ptr;
+
+ public:
+ /// Creates a new reference from the raw underlying C API representation.
+ Ref(const wasmtime_moduletype_t *ptr) : ptr(ptr) {}
+ /// Creates a reference to the given type.
+ Ref(const ModuleType &ty) : Ref(ty.ptr.get()) {}
+
+ /// Returns the list of types imported by this module.
+ ImportType::List imports() const {
+ ImportType::List list;
+ wasmtime_moduletype_imports(ptr, &list.list);
+ return list;
+ }
+
+ /// Returns the list of types exported by this module.
+ ExportType::List exports() const {
+ ExportType::List list;
+ wasmtime_moduletype_exports(ptr, &list.list);
+ return list;
+ }
+ };
+
+private:
+ Ref ref;
+ ModuleType(wasmtime_moduletype_t *ptr) : ptr(ptr), ref(ptr) {}
+
+public:
+ /// \brief Returns the underlying `Ref`, a non-owning reference pointing to
+ /// this instance.
+ Ref *operator->() { return &ref; }
+ /// \brief Returns the underlying `Ref`, a non-owning reference pointing to
+ /// this instance.
+ Ref *operator*() { return &ref; }
+};
+
+/**
+ * \brief Type information about a WebAssembly instance.
+ */
+class InstanceType {
+ friend class Instance;
+
+ struct deleter {
+ void operator()(wasmtime_instancetype_t *p) const {
+ wasmtime_instancetype_delete(p);
+ }
+ };
+
+ std::unique_ptr<wasmtime_instancetype_t, deleter> ptr;
+
+public:
+ /// Non-owning reference to an `InstanceType`, must not be used after the
+ /// original owner is deleted.
+ class Ref {
+ friend class InstanceType;
+
+ const wasmtime_instancetype_t *ptr;
+
+ public:
+ /// Creates a new reference from the raw underlying C API representation.
+ Ref(const wasmtime_instancetype_t *ptr) : ptr(ptr) {}
+ /// Creates a new reference to the provided type.
+ Ref(const InstanceType &ty) : Ref(ty.ptr.get()) {}
+
+ /// Returns the list of types exported by this instance.
+ ExportType::List exports() const {
+ ExportType::List list;
+ wasmtime_instancetype_exports(ptr, &list.list);
+ return list;
+ }
+ };
+
+private:
+ Ref ref;
+ InstanceType(wasmtime_instancetype_t *ptr) : ptr(ptr), ref(ptr) {}
+
+public:
+ /// \brief Returns the underlying `Ref`, a non-owning reference pointing to
+ /// this instance.
+ Ref *operator->() { return &ref; }
+ /// \brief Returns the underlying `Ref`, a non-owning reference pointing to
+ /// this instance.
+ Ref *operator*() { return &ref; }
+};
+
+/**
+ * \brief Generic type of a WebAssembly item.
+ */
+class ExternType {
+ friend class ExportType;
+ friend class ImportType;
+
+public:
+ /// \typedef Ref
+ /// \brief Non-owning reference to an item's type
+ ///
+ /// This cannot be used after the original owner has been deleted, and
+ /// otherwise this is used to determine what the actual type of the outer item
+ /// is.
+ typedef std::variant<FuncType::Ref, GlobalType::Ref, TableType::Ref,
+ MemoryType::Ref, ModuleType::Ref, InstanceType::Ref>
+ Ref;
+
+ /// Extract the type of the item imported by the provided type.
+ static Ref from_import(ImportType::Ref ty) {
+ // TODO: this would ideally be some sort of implicit constructor, unsure how
+ // to do that though...
+ return ref_from_c(ty.raw_type());
+ }
+
+ /// Extract the type of the item exported by the provided type.
+ static Ref from_export(ExportType::Ref ty) {
+ // TODO: this would ideally be some sort of implicit constructor, unsure how
+ // to do that though...
+ return ref_from_c(ty.raw_type());
+ }
+
+private:
+ static Ref ref_from_c(const wasm_externtype_t *ptr) {
+ switch (wasm_externtype_kind(ptr)) {
+ case WASM_EXTERN_FUNC:
+ return wasm_externtype_as_functype_const(ptr);
+ case WASM_EXTERN_GLOBAL:
+ return wasm_externtype_as_globaltype_const(ptr);
+ case WASM_EXTERN_TABLE:
+ return wasm_externtype_as_tabletype_const(ptr);
+ case WASM_EXTERN_MEMORY:
+ return wasm_externtype_as_memorytype_const(ptr);
+ case WASMTIME_EXTERN_MODULE:
+ // Should probably just add const versions of these functions to
+ // wasmtime's C API?
+ return wasmtime_externtype_as_moduletype(
+ const_cast<wasm_externtype_t *>(ptr)); // NOLINT
+ case WASMTIME_EXTERN_INSTANCE:
+ return wasmtime_externtype_as_instancetype(
+ const_cast<wasm_externtype_t *>(ptr)); // NOLINT
+ }
+ std::abort();
+ }
+};
+
+/**
+ * \brief Non-owning reference to a WebAssembly function frame as part of a
+ * `Trace`
+ *
+ * A `FrameRef` represents a WebAssembly function frame on the stack which was
+ * collected as part of a trap.
+ */
+class FrameRef {
+ wasm_frame_t *frame;
+
+public:
+ /// Returns the WebAssembly function index of this function, in the original
+ /// module.
+ uint32_t func_index() const { return wasm_frame_func_index(frame); }
+ /// Returns the offset, in bytes from the start of the function in the
+ /// original module, to this frame's program counter.
+ size_t func_offset() const { return wasm_frame_func_offset(frame); }
+ /// Returns the offset, in bytes from the start of the original module,
+ /// to this frame's program counter.
+ size_t module_offset() const { return wasm_frame_module_offset(frame); }
+
+ /// Returns the name, if present, associated with this function.
+ ///
+ /// Note that this requires that the `name` section is present in the original
+ /// WebAssembly binary.
+ std::optional<std::string_view> func_name() const {
+ const auto *name = wasmtime_frame_func_name(frame);
+ if (name != nullptr) {
+ return std::string_view(name->data, name->size);
+ }
+ return std::nullopt;
+ }
+
+ /// Returns the name, if present, associated with this function's module.
+ ///
+ /// Note that this requires that the `name` section is present in the original
+ /// WebAssembly binary.
+ std::optional<std::string_view> module_name() const {
+ const auto *name = wasmtime_frame_module_name(frame);
+ if (name != nullptr) {
+ return std::string_view(name->data, name->size);
+ }
+ return std::nullopt;
+ }
+};
+
+/**
+ * \brief An owned vector of `FrameRef` instances representing the WebAssembly
+ * call-stack on a trap.
+ *
+ * This can be used to iterate over the frames of a trap and determine what was
+ * running when a trap happened.
+ */
+class Trace {
+ friend class Trap;
+
+ wasm_frame_vec_t vec;
+
+ Trace(wasm_frame_vec_t vec) : vec(vec) {}
+
+public:
+ ~Trace() { wasm_frame_vec_delete(&vec); }
+
+ Trace(const Trace &other) = delete;
+ Trace(Trace &&other) = delete;
+ Trace &operator=(const Trace &other) = delete;
+ Trace &operator=(Trace &&other) = delete;
+
+ /// Iterator used to iterate over this trace.
+ typedef const FrameRef *iterator;
+
+ /// Returns the start of iteration
+ iterator begin() const {
+ return reinterpret_cast<FrameRef *>(&vec.data[0]); // NOLINT
+ }
+ /// Returns the end of iteration
+ iterator end() const {
+ return reinterpret_cast<FrameRef *>(&vec.data[vec.size]); // NOLINT
+ }
+ /// Returns the size of this trace, or how many frames it contains.
+ size_t size() const { return vec.size; }
+};
+
+/**
+ * \brief Information about a WebAssembly trap.
+ *
+ * Traps can happen during normal wasm execution (such as the `unreachable`
+ * instruction) but they can also happen in host-provided functions to a host
+ * function can simulate raising a trap.
+ *
+ * Traps have a message associated with them as well as a trace of WebAssembly
+ * frames on the stack.
+ */
+class Trap {
+ friend class Linker;
+ friend class Instance;
+ friend class Func;
+
+ struct deleter {
+ void operator()(wasm_trap_t *p) const { wasm_trap_delete(p); }
+ };
+
+ std::unique_ptr<wasm_trap_t, deleter> ptr;
+
+ Trap(wasm_trap_t *ptr) : ptr(ptr) {}
+
+public:
+ /// Creates a new host-defined trap with the specified message.
+ explicit Trap(std::string_view msg)
+ : Trap(wasmtime_trap_new(msg.data(), msg.size())) {}
+
+ /// Returns the descriptive message associated with this trap
+ std::string message() const {
+ wasm_byte_vec_t msg;
+ wasm_trap_message(ptr.get(), &msg);
+ std::string ret(msg.data, msg.size - 1);
+ wasm_byte_vec_delete(&msg);
+ return ret;
+ }
+
+ /// If this trap represents a call to `exit` for WASI, this will return the
+ /// optional error code associated with the exit trap.
+ std::optional<int32_t> i32_exit() const {
+ int32_t status = 0;
+ if (wasmtime_trap_exit_status(ptr.get(), &status)) {
+ return status;
+ }
+ return std::nullopt;
+ }
+
+ /// Returns the trace of WebAssembly frames associated with this trap.
+ Trace trace() const {
+ wasm_frame_vec_t frames;
+ wasm_trap_trace(ptr.get(), &frames);
+ return Trace(frames);
+ }
+};
+
+/// Structure used to represent either a `Trap` or an `Error`.
+struct TrapError {
+ /// Storage for what this trap represents.
+ std::variant<Trap, Error> data;
+
+ /// Creates a new `TrapError` from a `Trap`
+ TrapError(Trap t) : data(std::move(t)) {}
+ /// Creates a new `TrapError` from an `Error`
+ TrapError(Error e) : data(std::move(e)) {}
+
+ /// Dispatches internally to return the message associated with this error.
+ std::string message() {
+ if (auto *trap = std::get_if<Trap>(&data)) {
+ return trap->message();
+ }
+ if (auto *error = std::get_if<Error>(&data)) {
+ return std::string(error->message());
+ }
+ std::abort();
+ }
+};
+
+/// Result used by functions which can fail because of invariants being violated
+/// (such as a type error) as well as because of a WebAssembly trap.
+template <typename T> using TrapResult = Result<T, TrapError>;
+
+/**
+ * \brief Representation of a compiled WebAssembly module.
+ *
+ * This type contains JIT code of a compiled WebAssembly module. A `Module` is
+ * connected to an `Engine` and can only be instantiated within that `Engine`.
+ * You can inspect a `Module` for its type information. This is passed as an
+ * argument to other APIs to instantiate it.
+ */
+class Module {
+ friend class Store;
+ friend class Instance;
+ friend class Linker;
+
+ struct deleter {
+ void operator()(wasmtime_module_t *p) const { wasmtime_module_delete(p); }
+ };
+
+ std::unique_ptr<wasmtime_module_t, deleter> ptr;
+
+ Module(wasmtime_module_t *raw) : ptr(raw) {}
+
+public:
+ /// Copies another module into this one.
+ Module(const Module &other) : ptr(wasmtime_module_clone(other.ptr.get())) {}
+ /// Copies another module into this one.
+ Module &operator=(const Module &other) {
+ ptr.reset(wasmtime_module_clone(other.ptr.get()));
+ return *this;
+ }
+ ~Module() = default;
+ /// Moves resources from another module into this one.
+ Module(Module &&other) = default;
+ /// Moves resources from another module into this one.
+ Module &operator=(Module &&other) = default;
+
+ /**
+ * \brief Compiles a module from the WebAssembly text format.
+ *
+ * This function will automatically use `wat2wasm` on the input and then
+ * delegate to the #compile function.
+ */
+ [[nodiscard]] static Result<Module> compile(Engine &engine,
+ std::string_view wat) {
+ auto wasm = wat2wasm(wat);
+ if (!wasm) {
+ return wasm.err();
+ }
+ auto bytes = wasm.ok();
+ return compile(engine, bytes);
+ }
+
+ /**
+ * \brief Compiles a module from the WebAssembly binary format.
+ *
+ * This function compiles the provided WebAssembly binary specified by `wasm`
+ * within the compilation settings configured by `engine`. This method is
+ * synchronous and will not return until the module has finished compiling.
+ *
+ * This function can fail if the WebAssembly binary is invalid or doesn't
+ * validate (or similar).
+ */
+ [[nodiscard]] static Result<Module> compile(Engine &engine,
+ Span<uint8_t> wasm) {
+ wasmtime_module_t *ret = nullptr;
+ auto *error =
+ wasmtime_module_new(engine.ptr.get(), wasm.data(), wasm.size(), &ret);
+ if (error != nullptr) {
+ return Error(error);
+ }
+ return Module(ret);
+ }
+
+ /**
+ * \brief Validates the provided WebAssembly binary without compiling it.
+ *
+ * This function will validate whether the provided binary is indeed valid
+ * within the compilation settings of the `engine` provided.
+ */
+ [[nodiscard]] static Result<std::monostate> validate(Engine &engine,
+ Span<uint8_t> wasm) {
+ auto *error =
+ wasmtime_module_validate(engine.ptr.get(), wasm.data(), wasm.size());
+ if (error != nullptr) {
+ return Error(error);
+ }
+ return std::monostate();
+ }
+
+ /**
+ * \brief Deserializes a previous list of bytes created with `serialize`.
+ *
+ * This function is intended to be much faster than `compile` where it uses
+ * the artifacts of a previous compilation to quickly create an in-memory
+ * module ready for instantiation.
+ *
+ * It is not safe to pass arbitrary input to this function, it is only safe to
+ * pass in output from previous calls to `serialize`. For more information see
+ * the Rust documentation -
+ * https://docs.wasmtime.dev/api/wasmtime/struct.Module.html#method.deserialize
+ */
+ [[nodiscard]] static Result<Module> deserialize(Engine &engine,
+ Span<uint8_t> wasm) {
+ wasmtime_module_t *ret = nullptr;
+ auto *error = wasmtime_module_deserialize(engine.ptr.get(), wasm.data(),
+ wasm.size(), &ret);
+ if (error != nullptr) {
+ return Error(error);
+ }
+ return Module(ret);
+ }
+
+ /// Returns the type of this module, which can be used to inspect the
+ /// imports/exports.
+ ModuleType type() { return wasmtime_module_type(ptr.get()); }
+
+ /**
+ * \brief Serializes this module to a list of bytes.
+ *
+ * The returned bytes can then be used to later pass to `deserialize` to
+ * quickly recreate this module in a different process perhaps.
+ */
+ [[nodiscard]] Result<std::vector<uint8_t>> serialize() const {
+ wasm_byte_vec_t bytes;
+ auto *error = wasmtime_module_serialize(ptr.get(), &bytes);
+ if (error != nullptr) {
+ return Error(error);
+ }
+ std::vector<uint8_t> ret;
+ // NOLINTNEXTLINE TODO can this be done without triggering lints?
+ Span<uint8_t> raw(reinterpret_cast<uint8_t *>(bytes.data), bytes.size);
+ ret.assign(raw.begin(), raw.end());
+ wasm_byte_vec_delete(&bytes);
+ return ret;
+ }
+};
+
+/**
+ * \brief Handle used to interrupt execution of WebAssembly from another thread.
+ */
+class InterruptHandle {
+ friend class Store;
+
+ struct deleter {
+ void operator()(wasmtime_interrupt_handle_t *p) const {
+ wasmtime_interrupt_handle_delete(p);
+ }
+ };
+
+ std::unique_ptr<wasmtime_interrupt_handle_t, deleter> ptr;
+
+ InterruptHandle(wasmtime_interrupt_handle_t *ptr) : ptr(ptr) {}
+
+public:
+ /// Indicates that the WebAssembly executing in the store this handle is
+ /// connected to should be interrupted as soon as possible.
+ void interrupt() const { wasmtime_interrupt_handle_interrupt(ptr.get()); }
+};
+
+/**
+ * \brief Configuration for an instance of WASI.
+ *
+ * This is inserted into a store with `Store::Context::set_wasi`.
+ */
+class WasiConfig {
+ friend class Store;
+
+ struct deleter {
+ void operator()(wasi_config_t *p) const { wasi_config_delete(p); }
+ };
+
+ std::unique_ptr<wasi_config_t, deleter> ptr;
+
+public:
+ /// Creates a new configuration object with default settings.
+ WasiConfig() : ptr(wasi_config_new()) {}
+
+ /// Configures the argv explicitly with the given string array.
+ void argv(const std::vector<std::string> &args) {
+ std::vector<const char *> ptrs;
+ ptrs.reserve(args.size());
+ for (const auto &arg : args) {
+ ptrs.push_back(arg.c_str());
+ }
+
+ wasi_config_set_argv(ptr.get(), (int)args.size(), ptrs.data());
+ }
+
+ /// Configures the argv for wasm to be inherited from this process itself.
+ void inherit_argv() { wasi_config_inherit_argv(ptr.get()); }
+
+ /// Configures the environment variables available to wasm, specified here as
+ /// a list of pairs where the first element of the pair is the key and the
+ /// second element is the value.
+ void env(const std::vector<std::pair<std::string, std::string>> &env) {
+ std::vector<const char *> names;
+ std::vector<const char *> values;
+ for (const auto &[name, value] : env) {
+ names.push_back(name.c_str());
+ values.push_back(value.c_str());
+ }
+ wasi_config_set_env(ptr.get(), (int)env.size(), names.data(),
+ values.data());
+ }
+
+ /// Indicates that the entire environment of this process should be inherited
+ /// by the wasi configuration.
+ void inherit_env() { wasi_config_inherit_env(ptr.get()); }
+
+ /// Configures the provided file to be used for the stdin of this WASI
+ /// configuration.
+ [[nodiscard]] bool stdin_file(const std::string &path) {
+ return wasi_config_set_stdin_file(ptr.get(), path.c_str());
+ }
+
+ /// Configures this WASI configuration to inherit its stdin from the host
+ /// process.
+ void inherit_stdin() { return wasi_config_inherit_stdin(ptr.get()); }
+
+ /// Configures the provided file to be created and all stdout output will be
+ /// written there.
+ [[nodiscard]] bool stdout_file(const std::string &path) {
+ return wasi_config_set_stdout_file(ptr.get(), path.c_str());
+ }
+
+ /// Configures this WASI configuration to inherit its stdout from the host
+ /// process.
+ void inherit_stdout() { return wasi_config_inherit_stdout(ptr.get()); }
+
+ /// Configures the provided file to be created and all stderr output will be
+ /// written there.
+ [[nodiscard]] bool stderr_file(const std::string &path) {
+ return wasi_config_set_stderr_file(ptr.get(), path.c_str());
+ }
+
+ /// Configures this WASI configuration to inherit its stdout from the host
+ /// process.
+ void inherit_stderr() { return wasi_config_inherit_stderr(ptr.get()); }
+
+ /// Opens `path` to be opened as `guest_path` in the WASI pseudo-filesystem.
+ [[nodiscard]] bool preopen_dir(const std::string &path,
+ const std::string &guest_path) {
+ return wasi_config_preopen_dir(ptr.get(), path.c_str(), guest_path.c_str());
+ }
+};
+
+class Caller;
+
+/**
+ * \brief Owner of all WebAssembly objects
+ *
+ * A `Store` owns all WebAssembly objects such as instances, globals, functions,
+ * memories, etc. A `Store` is one of the main central points about working with
+ * WebAssembly since it's an argument to almost all APIs. The `Store` serves as
+ * a form of "context" to give meaning to the pointers of `Func` and friends.
+ *
+ * A `Store` can be sent between threads but it cannot generally be shared
+ * concurrently between threads. Memory associated with WebAssembly instances
+ * will be deallocated when the `Store` is deallocated.
+ */
+class Store {
+ struct deleter {
+ void operator()(wasmtime_store_t *p) const { wasmtime_store_delete(p); }
+ };
+
+ std::unique_ptr<wasmtime_store_t, deleter> ptr;
+
+public:
+ /// Creates a new `Store` within the provided `Engine`.
+ explicit Store(Engine &engine)
+ : ptr(wasmtime_store_new(engine.ptr.get(), nullptr, nullptr)) {}
+
+ /**
+ * \brief An interior pointer into a `Store`.
+ *
+ * A `Context` object is created from either a `Store` or a `Caller`. It is an
+ * interior pointer into a `Store` and cannot be used outside the lifetime of
+ * the original object it was created from.
+ *
+ * This object is an argument to most APIs in Wasmtime but typically doesn't
+ * need to be constructed explicitly since it can be created from a `Store&`
+ * or a `Caller&`.
+ */
+ class Context {
+ friend class Global;
+ friend class Table;
+ friend class Memory;
+ friend class Func;
+ friend class Instance;
+ friend class Linker;
+ wasmtime_context_t *ptr;
+
+ Context(wasmtime_context_t *ptr) : ptr(ptr) {}
+
+ public:
+ /// Creates a context referencing the provided `Store`.
+ Context(Store &store) : Context(wasmtime_store_context(store.ptr.get())) {}
+ /// Creates a context referencing the provided `Store`.
+ Context(Store *store) : Context(*store) {}
+ /// Creates a context referencing the provided `Caller`.
+ Context(Caller &caller);
+ /// Creates a context referencing the provided `Caller`.
+ Context(Caller *caller);
+
+ /// Runs a garbage collection pass in the referenced store to collect loose
+ /// `externref` values, if any are available.
+ void gc() { wasmtime_context_gc(ptr); }
+
+ /// Injects fuel to be consumed within this store.
+ ///
+ /// Stores start with 0 fuel and if `Config::consume_fuel` is enabled then
+ /// this is required if you want to let WebAssembly actually execute.
+ ///
+ /// Returns an error if fuel consumption isn't enabled.
+ [[nodiscard]] Result<std::monostate> add_fuel(uint64_t fuel) {
+ auto *error = wasmtime_context_add_fuel(ptr, fuel);
+ if (error != nullptr) {
+ return Error(error);
+ }
+ return std::monostate();
+ }
+
+ /// Returns the amount of fuel consumed so far by executing WebAssembly.
+ ///
+ /// Returns `std::nullopt` if fuel consumption is not enabled.
+ std::optional<uint64_t> fuel_consumed() const {
+ uint64_t fuel = 0;
+ if (wasmtime_context_fuel_consumed(ptr, &fuel)) {
+ return fuel;
+ }
+ return std::nullopt;
+ }
+
+ /// Configures the WASI state used by this store.
+ ///
+ /// This will only have an effect if used in conjunction with
+ /// `Linker::define_wasi` because otherwise no host functions will use the
+ /// WASI state.
+ [[nodiscard]] Result<std::monostate> set_wasi(WasiConfig config) {
+ auto *error = wasmtime_context_set_wasi(ptr, config.ptr.release());
+ if (error != nullptr) {
+ return Error(error);
+ }
+ return std::monostate();
+ }
+
+ /// Returns a handle, which can be sent to another thread, which can be used
+ /// to interrupt execution of WebAssembly within this `Store`.
+ ///
+ /// This requires `Config::interruptable` to be enabled to retun a handle.
+ std::optional<InterruptHandle> interrupt_handle() {
+ auto *handle = wasmtime_interrupt_handle_new(ptr);
+ if (handle != nullptr) {
+ return InterruptHandle(handle);
+ }
+ return std::nullopt;
+ }
+ };
+
+ /// Explicit function to acquire a `Context` from this store.
+ Context context() { return this; }
+};
+
+/**
+ * \brief Representation of a WebAssembly `externref` value.
+ *
+ * This class represents an value that cannot be forged by WebAssembly itself.
+ * All `ExternRef` values are guaranteed to be created by the host and its
+ * embedding. It's suitable to place private data structures in here which
+ * WebAssembly will not have access to, only other host functions will have
+ * access to them.
+ */
+class ExternRef {
+ friend class Val;
+
+ struct deleter {
+ void operator()(wasmtime_externref_t *p) const {
+ wasmtime_externref_delete(p);
+ }
+ };
+
+ std::unique_ptr<wasmtime_externref_t, deleter> ptr;
+
+ static void finalizer(void *ptr) {
+ std::unique_ptr<std::any> _ptr(static_cast<std::any *>(ptr));
+ }
+
+ ExternRef(wasmtime_externref_t *ptr) : ptr(ptr) {}
+
+public:
+ /// Creates a new `externref` value from the provided argument.
+ ///
+ /// Note that `val` should be safe to send across threads and should own any
+ /// memory that it points to. Also note that `ExternRef` is similar to a
+ /// `std::shared_ptr` in that there can be many references to the same value.
+ explicit ExternRef(std::any val)
+ : ExternRef(wasmtime_externref_new(
+ std::make_unique<std::any>(std::move(val)).release(), finalizer)) {}
+ /// Performs a shallow copy of another `externref` value, creating another
+ /// reference to it.
+ ExternRef(const ExternRef &other)
+ : ExternRef(wasmtime_externref_clone(other.ptr.get())) {}
+ /// Performs a shallow copy of another `externref` value, creating another
+ /// reference to it.
+ ExternRef &operator=(const ExternRef &other) {
+ ptr.reset(wasmtime_externref_clone(other.ptr.get()));
+ return *this;
+ }
+ /// Moves the resources pointed to by `other` into `this`.
+ ExternRef(ExternRef &&other) = default;
+ /// Moves the resources pointed to by `other` into `this`.
+ ExternRef &operator=(ExternRef &&other) = default;
+ ~ExternRef() = default;
+
+ /// Returns the underlying host data associated with this `ExternRef`.
+ std::any &data() {
+ return *static_cast<std::any *>(wasmtime_externref_data(ptr.get()));
+ }
+};
+
+class Func;
+class Global;
+class Instance;
+class Memory;
+class Table;
+
+/// \typedef Extern
+/// \brief Representation of an external WebAssembly item
+typedef std::variant<Instance, Module, Func, Global, Memory, Table> Extern;
+
+/**
+ * \brief Representation of a generic WebAssembly value.
+ *
+ * This is roughly equivalent to a tagged union of all possible WebAssembly
+ * values. This is later used as an argument with functions, globals, tables,
+ * etc.
+ */
+class Val {
+ friend class Global;
+ friend class Table;
+ friend class Func;
+
+ wasmtime_val_t val;
+
+ Val() : val{} {
+ val.kind = WASMTIME_I32;
+ val.of.i32 = 0;
+ }
+ Val(wasmtime_val_t val) : val(val) {}
+
+public:
+ /// Creates a new `i32` WebAssembly value.
+ Val(int32_t i32) : val{} {
+ val.kind = WASMTIME_I32;
+ val.of.i32 = i32;
+ }
+ /// Creates a new `i64` WebAssembly value.
+ Val(int64_t i64) : val{} {
+ val.kind = WASMTIME_I64;
+ val.of.i64 = i64;
+ }
+ /// Creates a new `f32` WebAssembly value.
+ Val(float f32) : val{} {
+ val.kind = WASMTIME_F32;
+ val.of.f32 = f32;
+ }
+ /// Creates a new `f64` WebAssembly value.
+ Val(double f64) : val{} {
+ val.kind = WASMTIME_F64;
+ val.of.f64 = f64;
+ }
+ /// Creates a new `v128` WebAssembly value.
+ Val(const wasmtime_v128 &v128) : val{} {
+ val.kind = WASMTIME_V128;
+ val.of.i32 = 0;
+ memcpy(&val.of.v128[0], &v128[0], sizeof(wasmtime_v128));
+ }
+ /// Creates a new `funcref` WebAssembly value.
+ Val(std::optional<Func> func);
+ /// Creates a new `funcref` WebAssembly value which is not `ref.null func`.
+ Val(Func func);
+ /// Creates a new `externref` value.
+ Val(std::optional<ExternRef> ptr) : val{} {
+ val.kind = WASMTIME_EXTERNREF;
+ val.of.externref = nullptr;
+ if (ptr) {
+ val.of.externref = ptr->ptr.release();
+ }
+ }
+ /// Creates a new `externref` WebAssembly value which is not `ref.null
+ /// extern`.
+ Val(ExternRef ptr);
+ /// Copies the contents of another value into this one.
+ Val(const Val &other) : val{} {
+ val.kind = WASMTIME_I32;
+ val.of.i32 = 0;
+ wasmtime_val_copy(&val, &other.val);
+ }
+ /// Moves the resources from another value into this one.
+ Val(Val &&other) noexcept : val{} {
+ val.kind = WASMTIME_I32;
+ val.of.i32 = 0;
+ std::swap(val, other.val);
+ }
+
+ ~Val() {
+ if (val.kind == WASMTIME_EXTERNREF && val.of.externref != nullptr) {
+ wasmtime_externref_delete(val.of.externref);
+ }
+ }
+
+ /// Copies the contents of another value into this one.
+ Val &operator=(const Val &other) noexcept {
+ if (val.kind == WASMTIME_EXTERNREF && val.of.externref != nullptr) {
+ wasmtime_externref_delete(val.of.externref);
+ }
+ wasmtime_val_copy(&val, &other.val);
+ return *this;
+ }
+ /// Moves the resources from another value into this one.
+ Val &operator=(Val &&other) noexcept {
+ std::swap(val, other.val);
+ return *this;
+ }
+
+ /// Returns the kind of value that this value has.
+ ValKind kind() const {
+ switch (val.kind) {
+ case WASMTIME_I32:
+ return ValKind::I32;
+ case WASMTIME_I64:
+ return ValKind::I64;
+ case WASMTIME_F32:
+ return ValKind::F32;
+ case WASMTIME_F64:
+ return ValKind::F64;
+ case WASMTIME_FUNCREF:
+ return ValKind::FuncRef;
+ case WASMTIME_EXTERNREF:
+ return ValKind::ExternRef;
+ case WASMTIME_V128:
+ return ValKind::V128;
+ }
+ std::abort();
+ }
+
+ /// Returns the underlying `i32`, requires `kind() == KindI32` or aborts the
+ /// process.
+ int32_t i32() const {
+ if (val.kind != WASMTIME_I32) {
+ std::abort();
+ }
+ return val.of.i32;
+ }
+
+ /// Returns the underlying `i64`, requires `kind() == KindI64` or aborts the
+ /// process.
+ int64_t i64() const {
+ if (val.kind != WASMTIME_I64) {
+ std::abort();
+ }
+ return val.of.i64;
+ }
+
+ /// Returns the underlying `f32`, requires `kind() == KindF32` or aborts the
+ /// process.
+ float f32() const {
+ if (val.kind != WASMTIME_F32) {
+ std::abort();
+ }
+ return val.of.f32;
+ }
+
+ /// Returns the underlying `f64`, requires `kind() == KindF64` or aborts the
+ /// process.
+ double f64() const {
+ if (val.kind != WASMTIME_F64) {
+ std::abort();
+ }
+ return val.of.f64;
+ }
+
+ /// Returns the underlying `v128`, requires `kind() == KindV128` or aborts
+ /// the process.
+ const wasmtime_v128 &v128() const {
+ if (val.kind != WASMTIME_V128) {
+ std::abort();
+ }
+ return val.of.v128;
+ }
+
+ /// Returns the underlying `externref`, requires `kind() == KindExternRef` or
+ /// aborts the process.
+ ///
+ /// Note that `externref` is a nullable reference, hence the `optional` return
+ /// value.
+ std::optional<ExternRef> externref() const {
+ if (val.kind != WASMTIME_EXTERNREF) {
+ std::abort();
+ }
+ if (val.of.externref != nullptr) {
+ return ExternRef(wasmtime_externref_clone(val.of.externref));
+ }
+ return std::nullopt;
+ }
+
+ /// Returns the underlying `funcref`, requires `kind() == KindFuncRef` or
+ /// aborts the process.
+ ///
+ /// Note that `funcref` is a nullable reference, hence the `optional` return
+ /// value.
+ std::optional<Func> funcref() const;
+};
+
+/**
+ * \brief Structure provided to host functions to lookup caller information or
+ * acquire a `Store::Context`.
+ *
+ * This structure is passed to all host functions created with `Func`. It can be
+ * used to create a `Store::Context`.
+ */
+class Caller {
+ friend class Func;
+ friend class Store;
+ wasmtime_caller_t *ptr;
+ Caller(wasmtime_caller_t *ptr) : ptr(ptr) {}
+
+public:
+ /// Attempts to load an exported item from the calling instance.
+ ///
+ /// For more information see the Rust documentation -
+ /// https://docs.wasmtime.dev/api/wasmtime/struct.Caller.html#method.get_export
+ std::optional<Extern> get_export(std::string_view name);
+
+ /// Explicitly acquire a `Store::Context` from this `Caller`.
+ Store::Context context() { return this; }
+};
+
+inline Store::Context::Context(Caller &caller)
+ : Context(wasmtime_caller_context(caller.ptr)) {}
+inline Store::Context::Context(Caller *caller) : Context(*caller) {}
+
+/**
+ * \brief Representation of a WebAssembly function.
+ *
+ * This class represents a WebAssembly function, either created through
+ * instantiating a module or a host function.
+ *
+ * Note that this type does not itself own any resources. It points to resources
+ * owned within a `Store` and the `Store` must be passed in as the first
+ * argument to the functions defined on `Func`. Note that if the wrong `Store`
+ * is passed in then the process will be aborted.
+ */
+class Func {
+ friend class Val;
+ friend class Instance;
+
+ wasmtime_func_t func;
+
+ template <typename F>
+ static wasm_trap_t *raw_callback(void *env, wasmtime_caller_t *caller,
+ const wasmtime_val_t *args, size_t nargs,
+ wasmtime_val_t *results, size_t nresults) {
+ F *func = reinterpret_cast<F *>(env); // NOLINT
+ Span<const Val> args_span(reinterpret_cast<const Val *>(args), // NOLINT
+ nargs);
+ Span<Val> results_span(reinterpret_cast<Val *>(results), // NOLINT
+ nresults);
+ Result<std::monostate, Trap> result =
+ (*func)(Caller(caller), args_span, results_span);
+ if (!result) {
+ return result.err().ptr.release();
+ }
+ return nullptr;
+ }
+
+ template <typename F> static void raw_finalize(void *env) {
+ std::unique_ptr<F> ptr(reinterpret_cast<F *>(env)); // NOLINT
+ }
+
+public:
+ /// Creates a new function from the raw underlying C API representation.
+ Func(wasmtime_func_t func) : func(func) {}
+
+ /**
+ * \brief Creates a new host-defined function.
+ *
+ * This constructor is used to create a host function within the store
+ * provided. This is how WebAssembly can call into the host and make use of
+ * external functionality.
+ *
+ * \param cx the store to create the function within
+ * \param ty the type of the function that will be created
+ * \param f the host callback to be executed when this function is called.
+ *
+ * The parameter `f` is expected to be a lambda (or a lambda lookalike) which
+ * takes three parameters:
+ *
+ * * The first parameter is a `Caller` to get recursive access to the store
+ * and other caller state.
+ * * The second parameter is a `Span<const Val>` which is the list of
+ * parameters to the function. These parameters are guaranteed to be of the
+ * types specified by `ty` when constructing this function.
+ * * The last argument is `Span<Val>` which is where to write the return
+ * values of the function. The function must produce the types of values
+ * specified by `ty` or otherwise a trap will be raised.
+ *
+ * The parameter `f` is expected to return `Result<std::monostate, Trap>`.
+ * This allows `f` to raise a trap if desired, or otherwise return no trap and
+ * finish successfully. If a trap is raised then the results pointer does not
+ * need to be written to.
+ */
+ template <typename F>
+ Func(Store::Context cx, const FuncType &ty, F f) : func({}) {
+ wasmtime_func_new(cx.ptr, ty.ptr.get(), raw_callback<F>,
+ std::make_unique<F>(f).release(), raw_finalize<F>, &func);
+ }
+
+ /**
+ * \brief Invoke a WebAssembly function.
+ *
+ * This function will execute this WebAssembly function. This function muts be
+ * defined within the `cx`'s store provided. The `params` argument is the list
+ * of parameters that are passed to the wasm function, and the types of the
+ * values within `params` must match the type signature of this function.
+ *
+ * This may return one of three values:
+ *
+ * * First the function could succeed, returning a vector of values
+ * representing the results of the function.
+ * * Otherwise a `Trap` might be generated by the WebAssembly function.
+ * * Finally an `Error` could be returned indicating that `params` were not of
+ * the right type.
+ */
+ [[nodiscard]] TrapResult<std::vector<Val>>
+ call(Store::Context cx, const std::vector<Val> &params) const {
+ std::vector<wasmtime_val_t> raw_params;
+ raw_params.reserve(params.size());
+ for (const auto &param : params) {
+ raw_params.push_back(param.val);
+ }
+ size_t nresults = this->type(cx)->results().size();
+ std::vector<wasmtime_val_t> raw_results(nresults);
+
+ wasm_trap_t *trap = nullptr;
+ auto *error =
+ wasmtime_func_call(cx.ptr, &func, raw_params.data(), raw_params.size(),
+ raw_results.data(), raw_results.capacity(), &trap);
+ if (error != nullptr) {
+ return TrapError(Error(error));
+ }
+ if (trap != nullptr) {
+ return TrapError(Trap(trap));
+ }
+
+ std::vector<Val> results;
+ results.reserve(nresults);
+ for (size_t i = 0; i < nresults; i++) {
+ results.push_back(raw_results[i]);
+ }
+ return results;
+ }
+
+ /// Returns the type of this function.
+ FuncType type(Store::Context cx) const {
+ return wasmtime_func_type(cx.ptr, &func);
+ }
+};
+
+inline Val::Val(std::optional<Func> func) : val{} {
+ val.kind = WASMTIME_FUNCREF;
+ val.of.funcref.store_id = 0;
+ val.of.funcref.index = 0;
+ if (func) {
+ val.of.funcref = (*func).func;
+ }
+}
+
+inline Val::Val(Func func) : Val(std::optional(func)) {}
+inline Val::Val(ExternRef ptr) : Val(std::optional(ptr)) {}
+
+inline std::optional<Func> Val::funcref() const {
+ if (val.kind != WASMTIME_FUNCREF) {
+ std::abort();
+ }
+ if (val.of.funcref.store_id == 0) {
+ return std::nullopt;
+ }
+ return Func(val.of.funcref);
+}
+
+/**
+ * \brief A WebAssembly global.
+ *
+ * This class represents a WebAssembly global, either created through
+ * instantiating a module or a host global. Globals contain a WebAssembly value
+ * and can be read and optionally written to.
+ *
+ * Note that this type does not itself own any resources. It points to resources
+ * owned within a `Store` and the `Store` must be passed in as the first
+ * argument to the functions defined on `Global`. Note that if the wrong `Store`
+ * is passed in then the process will be aborted.
+ */
+class Global {
+ friend class Instance;
+ wasmtime_global_t global;
+
+public:
+ /// Creates as global from the raw underlying C API representation.
+ Global(wasmtime_global_t global) : global(global) {}
+
+ /**
+ * \brief Create a new WebAssembly global.
+ *
+ * \param cx the store in which to create the global
+ * \param ty the type that this global will have
+ * \param init the initial value of the global
+ *
+ * This function can fail if `init` does not have a value that matches `ty`.
+ */
+ [[nodiscard]] static Result<Global>
+ create(Store::Context cx, const GlobalType &ty, const Val &init) {
+ wasmtime_global_t global;
+ auto *error = wasmtime_global_new(cx.ptr, ty.ptr.get(), &init.val, &global);
+ if (error != nullptr) {
+ return Error(error);
+ }
+ return Global(global);
+ }
+
+ /// Returns the type of this global.
+ GlobalType type(Store::Context cx) const {
+ return wasmtime_global_type(cx.ptr, &global);
+ }
+
+ /// Returns the current value of this global.
+ Val get(Store::Context cx) const {
+ Val val;
+ wasmtime_global_get(cx.ptr, &global, &val.val);
+ return val;
+ }
+
+ /// Sets this global to a new value.
+ ///
+ /// This can fail if `val` has the wrong type or if this global isn't mutable.
+ [[nodiscard]] Result<std::monostate> set(Store::Context cx,
+ const Val &val) const {
+ auto *error = wasmtime_global_set(cx.ptr, &global, &val.val);
+ if (error != nullptr) {
+ return Error(error);
+ }
+ return std::monostate();
+ }
+};
+
+/**
+ * \brief A WebAssembly table.
+ *
+ * This class represents a WebAssembly table, either created through
+ * instantiating a module or a host table. Tables are contiguous vectors of
+ * WebAssembly reference types, currently either `externref` or `funcref`.
+ *
+ * Note that this type does not itself own any resources. It points to resources
+ * owned within a `Store` and the `Store` must be passed in as the first
+ * argument to the functions defined on `Table`. Note that if the wrong `Store`
+ * is passed in then the process will be aborted.
+ */
+class Table {
+ friend class Instance;
+ wasmtime_table_t table;
+
+public:
+ /// Creates a new table from the raw underlying C API representation.
+ Table(wasmtime_table_t table) : table(table) {}
+
+ /**
+ * \brief Creates a new host-defined table.
+ *
+ * \param cx the store in which to create the table.
+ * \param ty the type of the table to be created
+ * \param init the initial value for all table slots.
+ *
+ * Returns an error if `init` has the wrong value for the `ty` specified.
+ */
+ [[nodiscard]] static Result<Table>
+ create(Store::Context cx, const TableType &ty, const Val &init) {
+ wasmtime_table_t table;
+ auto *error = wasmtime_table_new(cx.ptr, ty.ptr.get(), &init.val, &table);
+ if (error != nullptr) {
+ return Error(error);
+ }
+ return Table(table);
+ }
+
+ /// Returns the type of this table.
+ TableType type(Store::Context cx) const {
+ return wasmtime_table_type(cx.ptr, &table);
+ }
+
+ /// Returns the size, in elements, that the table currently has.
+ size_t size(Store::Context cx) const {
+ return wasmtime_table_size(cx.ptr, &table);
+ }
+
+ /// Loads a value from the specified index in this table.
+ ///
+ /// Returns `std::nullopt` if `idx` is out of bounds.
+ std::optional<Val> get(Store::Context cx, uint32_t idx) const {
+ Val val;
+ if (wasmtime_table_get(cx.ptr, &table, idx, &val.val)) {
+ return val;
+ }
+ return std::nullopt;
+ }
+
+ /// Stores a value into the specified index in this table.
+ ///
+ /// Returns an error if `idx` is out of bounds or if `val` has the wrong type.
+ [[nodiscard]] Result<std::monostate> set(Store::Context cx, uint32_t idx,
+ const Val &val) const {
+ auto *error = wasmtime_table_set(cx.ptr, &table, idx, &val.val);
+ if (error != nullptr) {
+ return Error(error);
+ }
+ return std::monostate();
+ }
+
+ /// Grow this table.
+ ///
+ /// \param cx the store that owns this table.
+ /// \param delta the number of new elements to be added to this table.
+ /// \param init the initial value of all new elements in this table.
+ ///
+ /// Returns an error if `init` has the wrong type for this table. Otherwise
+ /// returns the previous size of the table before growth.
+ [[nodiscard]] Result<uint32_t> grow(Store::Context cx, uint32_t delta,
+ const Val &init) const {
+ uint32_t prev = 0;
+ auto *error = wasmtime_table_grow(cx.ptr, &table, delta, &init.val, &prev);
+ if (error != nullptr) {
+ return Error(error);
+ }
+ return prev;
+ }
+};
+
+/**
+ * \brief A WebAssembly linear memory.
+ *
+ * This class represents a WebAssembly memory, either created through
+ * instantiating a module or a host memory.
+ *
+ * Note that this type does not itself own any resources. It points to resources
+ * owned within a `Store` and the `Store` must be passed in as the first
+ * argument to the functions defined on `Table`. Note that if the wrong `Store`
+ * is passed in then the process will be aborted.
+ */
+class Memory {
+ friend class Instance;
+ wasmtime_memory_t memory;
+
+public:
+ /// Creates a new memory from the raw underlying C API representation.
+ Memory(wasmtime_memory_t memory) : memory(memory) {}
+
+ /// Creates a new host-defined memory with the type specified.
+ [[nodiscard]] static Result<Memory> create(Store::Context cx,
+ const MemoryType &ty) {
+ wasmtime_memory_t memory;
+ auto *error = wasmtime_memory_new(cx.ptr, ty.ptr.get(), &memory);
+ if (error != nullptr) {
+ return Error(error);
+ }
+ return Memory(memory);
+ }
+
+ /// Returns the type of this memory.
+ MemoryType type(Store::Context cx) const {
+ return wasmtime_memory_type(cx.ptr, &memory);
+ }
+
+ /// Returns the size, in WebAssembly pages, of this memory.
+ uint32_t size(Store::Context cx) const {
+ return wasmtime_memory_size(cx.ptr, &memory);
+ }
+
+ /// Returns a `span` of where this memory is located in the host.
+ ///
+ /// Note that embedders need to be very careful in their usage of the returned
+ /// `span`. It can be invalidated with calls to `grow` and/or calls into
+ /// WebAssembly.
+ Span<uint8_t> data(Store::Context cx) const {
+ auto *base = wasmtime_memory_data(cx.ptr, &memory);
+ auto size = wasmtime_memory_data_size(cx.ptr, &memory);
+ return {base, size};
+ }
+
+ /// Grows the memory by `delta` WebAssembly pages.
+ ///
+ /// On success returns the previous size of this memory in units of
+ /// WebAssembly pages.
+ [[nodiscard]] Result<uint32_t> grow(Store::Context cx, uint32_t delta) const {
+ uint32_t prev = 0;
+ auto *error = wasmtime_memory_grow(cx.ptr, &memory, delta, &prev);
+ if (error != nullptr) {
+ return Error(error);
+ }
+ return prev;
+ }
+};
+
+/**
+ * \brief A WebAssembly instance.
+ *
+ * This class represents a WebAssembly instance, created by instantiating a
+ * module. An instance is the collection of items exported by the module, which
+ * can be accessed through the `Store` that owns the instance.
+ *
+ * Note that this type does not itself own any resources. It points to resources
+ * owned within a `Store` and the `Store` must be passed in as the first
+ * argument to the functions defined on `Instance`. Note that if the wrong
+ * `Store` is passed in then the process will be aborted.
+ */
+class Instance {
+ friend class Linker;
+ friend class Caller;
+
+ wasmtime_instance_t instance;
+
+ static Extern cvt(wasmtime_extern_t &e) {
+ switch (e.kind) {
+ case WASMTIME_EXTERN_FUNC:
+ return Func(e.of.func);
+ case WASMTIME_EXTERN_GLOBAL:
+ return Global(e.of.global);
+ case WASMTIME_EXTERN_MEMORY:
+ return Memory(e.of.memory);
+ case WASMTIME_EXTERN_TABLE:
+ return Table(e.of.table);
+ case WASMTIME_EXTERN_INSTANCE:
+ return Instance(e.of.instance);
+ case WASMTIME_EXTERN_MODULE:
+ return Module(e.of.module);
+ }
+ std::abort();
+ }
+
+ static void cvt(const Extern &e, wasmtime_extern_t &raw) {
+ if (const auto *func = std::get_if<Func>(&e)) {
+ raw.kind = WASMTIME_EXTERN_FUNC;
+ raw.of.func = func->func;
+ } else if (const auto *global = std::get_if<Global>(&e)) {
+ raw.kind = WASMTIME_EXTERN_GLOBAL;
+ raw.of.global = global->global;
+ } else if (const auto *table = std::get_if<Table>(&e)) {
+ raw.kind = WASMTIME_EXTERN_TABLE;
+ raw.of.table = table->table;
+ } else if (const auto *memory = std::get_if<Memory>(&e)) {
+ raw.kind = WASMTIME_EXTERN_MEMORY;
+ raw.of.memory = memory->memory;
+ } else if (const auto *instance = std::get_if<Instance>(&e)) {
+ raw.kind = WASMTIME_EXTERN_INSTANCE;
+ raw.of.instance = instance->instance;
+ } else if (const auto *module = std::get_if<Module>(&e)) {
+ raw.kind = WASMTIME_EXTERN_MODULE;
+ raw.of.module = module->ptr.get();
+ } else {
+ std::abort();
+ }
+ }
+
+public:
+ /// Creates a new instance from the raw underlying C API representation.
+ Instance(wasmtime_instance_t instance) : instance(instance) {}
+
+ /**
+ * \brief Instantiates the module `m` with the provided `imports`
+ *
+ * \param cx the store in which to instantiate the provided module
+ * \param m the module to instantiate
+ * \param imports the list of imports to use to instantiate the module
+ *
+ * This `imports` parameter is expected to line up 1:1 with the imports
+ * required by the `m`. The type of `m` can be inspected to determine in which
+ * order to provide the imports. Note that this is a relatively low-level API
+ * and it's generally recommended to use `Linker` instead for name-based
+ * instantiation.
+ *
+ * This function can return an error if any of the `imports` have the wrong
+ * type, or if the wrong number of `imports` is provided.
+ */
+ [[nodiscard]] static TrapResult<Instance>
+ create(Store::Context cx, const Module &m,
+ const std::vector<Extern> &imports) {
+ std::vector<wasmtime_extern_t> raw_imports;
+ for (const auto &item : imports) {
+ raw_imports.push_back(wasmtime_extern_t{});
+ auto &last = raw_imports.back();
+ Instance::cvt(item, last);
+ }
+ wasmtime_instance_t instance;
+ wasm_trap_t *trap = nullptr;
+ auto *error = wasmtime_instance_new(cx.ptr, m.ptr.get(), raw_imports.data(),
+ raw_imports.size(), &instance, &trap);
+ if (error != nullptr) {
+ return TrapError(Error(error));
+ }
+ if (trap != nullptr) {
+ return TrapError(Trap(trap));
+ }
+ return Instance(instance);
+ }
+
+ /// Returns the type of this instance.
+ InstanceType type(Store::Context cx) const {
+ return wasmtime_instance_type(cx.ptr, &instance);
+ }
+
+ /**
+ * \brief Load an instance's export by name.
+ *
+ * This function will look for an export named `name` on this instance and, if
+ * found, return it as an `Extern`.
+ */
+ std::optional<Extern> get(Store::Context cx, std::string_view name) {
+ wasmtime_extern_t e;
+ if (!wasmtime_instance_export_get(cx.ptr, &instance, name.data(),
+ name.size(), &e)) {
+ return std::nullopt;
+ }
+ return Instance::cvt(e);
+ }
+
+ /**
+ * \brief Load an instance's export by index.
+ *
+ * This function will look for the `idx`th export of this instance. This will
+ * return both the name of the export as well as the exported item itself.
+ */
+ std::optional<std::pair<std::string_view, Extern>> get(Store::Context cx,
+ size_t idx) {
+ wasmtime_extern_t e;
+ // I'm not sure why clang-tidy thinks this is using va_list or anything
+ // related to that...
+ // NOLINTNEXTLINE(cppcoreguidelines-pro-type-vararg)
+ char *name = nullptr;
+ size_t len = 0;
+ if (!wasmtime_instance_export_nth(cx.ptr, &instance, idx, &name, &len,
+ &e)) {
+ return std::nullopt;
+ }
+ std::string_view n(name, len);
+ return std::pair(n, Instance::cvt(e));
+ }
+};
+
+inline std::optional<Extern> Caller::get_export(std::string_view name) {
+ wasmtime_extern_t item;
+ if (wasmtime_caller_export_get(ptr, name.data(), name.size(), &item)) {
+ return Instance::cvt(item);
+ }
+ return std::nullopt;
+}
+
+/**
+ * \brief Helper class for linking modules together with name-based resolution.
+ *
+ * This class is used for easily instantiating `Module`s by defining names into
+ * the linker and performing name-based resolution during instantiation. A
+ * `Linker` can also be used to link in WASI functions to instantiate a module.
+ */
+class Linker {
+ struct deleter {
+ void operator()(wasmtime_linker_t *p) const { wasmtime_linker_delete(p); }
+ };
+
+ std::unique_ptr<wasmtime_linker_t, deleter> ptr;
+
+public:
+ /// Creates a new linker which will instantiate in the given engine.
+ explicit Linker(Engine &engine)
+ : ptr(wasmtime_linker_new(engine.ptr.get())) {}
+
+ /// Configures whether shadowing previous names is allowed or not.
+ ///
+ /// By default shadowing is not allowed.
+ void allow_shadowing(bool allow) {
+ wasmtime_linker_allow_shadowing(ptr.get(), allow);
+ }
+
+ /// Defines the provided item into this linker with the given name.
+ [[nodiscard]] Result<std::monostate>
+ define(std::string_view module, std::string_view name, const Extern &item) {
+ wasmtime_extern_t raw;
+ Instance::cvt(item, raw);
+ auto *error =
+ wasmtime_linker_define(ptr.get(), module.data(), module.size(),
+ name.data(), name.size(), &raw);
+ if (error != nullptr) {
+ return Error(error);
+ }
+ return std::monostate();
+ }
+
+ /// Defines WASI functions within this linker.
+ ///
+ /// Note that `Store::Context::set_wasi` must also be used for instantiated
+ /// modules to have access to configured WASI state.
+ [[nodiscard]] Result<std::monostate> define_wasi() {
+ auto *error = wasmtime_linker_define_wasi(ptr.get());
+ if (error != nullptr) {
+ return Error(error);
+ }
+ return std::monostate();
+ }
+
+ /// Defines all exports of the `instance` provided in this linker with the
+ /// given module name of `name`.
+ [[nodiscard]] Result<std::monostate>
+ define_instance(Store::Context cx, std::string_view name, Instance instance) {
+ auto *error = wasmtime_linker_define_instance(
+ ptr.get(), cx.ptr, name.data(), name.size(), &instance.instance);
+ if (error != nullptr) {
+ return Error(error);
+ }
+ return std::monostate();
+ }
+
+ /// Instantiates the module `m` provided within the store `cx` using the items
+ /// defined within this linker.
+ [[nodiscard]] TrapResult<Instance> instantiate(Store::Context cx,
+ const Module &m) {
+ wasmtime_instance_t instance;
+ wasm_trap_t *trap = nullptr;
+ auto *error = wasmtime_linker_instantiate(ptr.get(), cx.ptr, m.ptr.get(),
+ &instance, &trap);
+ if (error != nullptr) {
+ return TrapError(Error(error));
+ }
+ if (trap != nullptr) {
+ return TrapError(Trap(trap));
+ }
+ return Instance(instance);
+ }
+
+ /// Defines instantiations of the module `m` within this linker under the
+ /// given `name`.
+ [[nodiscard]] Result<std::monostate>
+ module(Store::Context cx, std::string_view name, const Module &m) {
+ auto *error = wasmtime_linker_module(ptr.get(), cx.ptr, name.data(),
+ name.size(), m.ptr.get());
+ if (error != nullptr) {
+ return Error(error);
+ }
+ return std::monostate();
+ }
+
+ /// Attempts to load the specified named item from this linker, returning
+ /// `std::nullopt` if it was not defiend.
+ [[nodiscard]] std::optional<Extern>
+ get(Store::Context cx, std::string_view module, std::string_view name) {
+ wasmtime_extern_t item;
+ if (wasmtime_linker_get(ptr.get(), cx.ptr, module.data(), module.size(),
+ name.data(), name.size(), &item)) {
+ return Instance::cvt(item);
+ }
+ return std::nullopt;
+ }
+
+ /// Loads the "default" function, according to WASI commands and reactors, of
+ /// the module named `name` in this linker.
+ [[nodiscard]] Result<Func> get_default(Store::Context cx,
+ std::string_view name) {
+ wasmtime_func_t item;
+ auto *error = wasmtime_linker_get_default(ptr.get(), cx.ptr, name.data(),
+ name.size(), &item);
+ if (error != nullptr) {
+ return Error(error);
+ }
+ return Func(item);
+ }
+};
+
+} // namespace wasmtime
+
+#endif // WASMTIME_HH

[Commit Bot]

[Commit Bot]

From: Piotr Sarna <sa...@scylladb.com>
Committer: Piotr Sarna <sa...@scylladb.com>

Branch: master