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.

crates/c-api/include/wasmtime/memory.h

@@ -0,0 +1,90 @@
+/**
+ * \file wasmtime/memory.h
+ *
+ * Wasmtime API for interacting with wasm memories.
+ */
+
+#ifndef WASMTIME_MEMORY_H
+#define WASMTIME_MEMORY_H
+
+#include <wasm.h>
+#include <wasmtime/extern.h>
+#include <wasmtime/store.h>
+#include <wasmtime/error.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * \brief Creates a new WebAssembly linear memory
+ *
+ * \param store the store to create the memory within
+ * \param ty the type of the memory to create
+ * \param ret where to store the returned memory
+ *
+ * If an error happens when creating the memory it's returned and owned by the
+ * caller. If an error happens then `ret` is not filled in.
+ */
+WASM_API_EXTERN wasmtime_error_t *wasmtime_memory_new(
+    wasmtime_context_t *store,
+    const wasm_memorytype_t* ty,
+    wasmtime_memory_t *ret
+);
+
+/**
+ * \brief Returns the tyep of the memory specified
+ */
+WASM_API_EXTERN wasm_memorytype_t* wasmtime_memory_type(
+    const wasmtime_context_t *store,
+    const wasmtime_memory_t *memory
+);
+
+/**
+ * \brief Returns the base pointer in memory where the linear memory starts.
+ */
+WASM_API_EXTERN uint8_t *wasmtime_memory_data(
+    const wasmtime_context_t *store,
+    const wasmtime_memory_t *memory
+);
+
+/**
+ * \brief Returns the byte length of this linear memory.
+ */
+WASM_API_EXTERN size_t wasmtime_memory_data_size(
+    const wasmtime_context_t *store,
+    const wasmtime_memory_t *memory
+);
+
+/**
+ * \brief Returns the length, in WebAssembly pages, of this linear memory
+ */
+WASM_API_EXTERN uint32_t wasmtime_memory_size(
+    const wasmtime_context_t *store,
+    const wasmtime_memory_t *memory
+);
+
+/**
+ * \brief Attempts to grow the specified memory by `delta` pages.
+ *
+ * \param store the store that owns `memory`
+ * \param memory the memory to grow
+ * \param delta the number of pages to grow by
+ * \param prev_size where to store the previous size of memory
+ *
+ * If memory cannot be grown then `prev_size` is left unchanged and an error is
+ * returned. Otherwise `prev_size` is set to the previous size of the memory, in
+ * WebAssembly pages, and `NULL` is returned.
+ */
+WASM_API_EXTERN wasmtime_error_t *wasmtime_memory_grow(
+    wasmtime_context_t *store,
+    const wasmtime_memory_t *memory,
+    uint32_t delta,
+    uint32_t *prev_size
+);
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
+#endif // WASMTIME_MEMORY_H