Add get_runtime_size for JS

Cargo.lock

@@ -2315,6 +2315,17 @@ dependencies = [
  "serde_derive",
 ]
 
+[[package]]
+name = "serde-wasm-bindgen"
+version = "0.4.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e3b4c031cd0d9014307d82b8abf653c0290fbdaeb4c02d00c63cf52f728628bf"
+dependencies = [
+ "js-sys",
+ "serde",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "serde_bytes"
 version = "0.11.7"
@@ -3070,6 +3081,8 @@ dependencies = [
  "js-sys",
  "macro-wasmer-universal-test",
  "more-asserts",
+ "serde",
+ "serde-wasm-bindgen",
  "target-lexicon 0.12.4",
  "tempfile",
  "thiserror",

lib/api/Cargo.toml

@@ -68,6 +68,9 @@ wasmer-derive = { path = "../derive", version = "=3.0.0-beta.2" }
 # - Optional dependencies for `js`.
 wasmparser = { version = "0.83", default-features = false, optional = true }
 hashbrown = { version = "0.11", optional = true }
+serde-wasm-bindgen = { version = "0.4.5" }
+serde = { version = "1.0", features = ["derive"] }
+
 # - Development Dependencies for `js`.
 [target.'cfg(target_arch = "wasm32")'.dev-dependencies]
 wat = "1.0"

lib/api/src/js/export.rs

@@ -3,9 +3,10 @@ use crate::js::store::{AsStoreMut, AsStoreRef, InternalStoreHandle};
 use crate::js::wasm_bindgen_polyfill::Global;
 use js_sys::Function;
 use js_sys::WebAssembly::{Memory, Table};
+use serde::{Deserialize, Serialize};
 use std::fmt;
 use wasm_bindgen::{JsCast, JsValue};
-use wasmer_types::{ExternType, FunctionType, GlobalType, MemoryType, TableType};
+use wasmer_types::{ExternType, FunctionType, GlobalType, MemoryType, TableType, WASM_PAGE_SIZE};
 
 /// Represents linear memory that is managed by the javascript runtime
 #[derive(Clone, Debug, PartialEq)]
@@ -17,13 +18,27 @@ pub struct VMMemory {
 unsafe impl Send for VMMemory {}
 unsafe impl Sync for VMMemory {}
 
+#[derive(Serialize, Deserialize)]
+struct DummyBuffer {
+    #[serde(rename = "byteLength")]
+    byte_length: u32,
+}
+
 impl VMMemory {
     pub(crate) fn new(memory: Memory, ty: MemoryType) -> Self {
         Self { memory, ty }
     }
 
+    /// Returns the size of the memory buffer in pages
     pub fn get_runtime_size(&self) -> u32 {
-        self.memory.get_runtime_size()
+        let dummy: DummyBuffer = match serde_wasm_bindgen::from_value(self.memory.buffer()) {
+            Ok(o) => o,
+            Err(_) => return 0,
+        };
+        if dummy.byte_length == 0 {
+            return 0;
+        }
+        dummy.byte_length / 65536
     }
 
     /// Attempts to clone this memory (if its clonable)
@@ -61,7 +76,7 @@ impl VMTable {
         Self { table, ty }
     }
     pub fn get_runtime_size(&self) -> u32 {
-        self.table.get_runtime_size()
+        self.table.length()
     }
 }