Make it work

Author: surma

lib/asbind-instance/asbind-instance.js

@@ -4,12 +4,10 @@ import { asbindInstantiate, asbindInstantiateSync } from "./instantiate";
 import { bindImportFunction, bindExportFunction } from "./bind-function";
 import { isReservedExportKey } from "./reserved-export-keys";
 
+const SECTION_NAME = "as-bind_bindings";
+
 // Need to traverse the importObject and bind all import functions
-const traverseObjectAndRunCallbackForFunctions = (
-  baseObject,
-  keys,
-  callback
-) => {
+function traverseObjectAndRunCallbackForFunctions(baseObject, keys, callback) {
   if (!baseObject) {
     return;
   }
@@ -26,7 +24,32 @@ const traverseObjectAndRunCallbackForFunctions = (
       );
     }
   });
-};
+}
+
+async function compileStreaming(source) {
+  if (WebAssembly.compileStreaming) {
+    return WebAssembly.compileStreaming(source);
+  }
+  source = await Promise.resolve(souce);
+  if (source instanceof Response) {
+    source = await source.arrayBuffer();
+  }
+  return WebAssembly.compile(source);
+}
+
+function extractTypeDescriptor(module) {
+  const sections = WebAssembly.Module.customSections(module, SECTION_NAME);
+  console.assert(
+    sections.length === 1,
+    `Need exactly one custom section ${JSON.stringify(SECTION_NAME)}`
+  );
+  const str = new TextDecoder("utf8").decode(new Uint8Array(sections[0]));
+  try {
+    return JSON.parse(str);
+  } catch (e) {
+    throw Error(`Couldn’t decode type descriptor: ${e.message}`);
+  }
+}
 
 export default class AsbindInstance {
   constructor() {
@@ -35,26 +58,47 @@ export default class AsbindInstance {
     this.importObject = {};
   }
 
+  _validate() {
+    if (
+      !WebAssembly.Module.exports(this.module).find(exp => exp.name === "__new")
+    ) {
+      throw Error(
+        "The AssemblyScript wasm module was not built with --exportRuntime, which is required."
+      );
+    }
+    if (
+      !WebAssembly.Module.exports(this.module).find(
+        exp => exp.name === "__asbind_entryfile_flaga"
+      )
+    ) {
+      throw new Error(
+        "The AssemblyScript wasm module was not built with the as-bind entryfile. Please see the as-bind documentation (Quick Start), and rebuild your AssemblyScript wasm module."
+      );
+    }
+  }
+
   async _instantiate(source, importObject) {
+    this.module = await compileStreaming(source);
+    this._validate();
+    this.typeDescriptor = extractTypeDescriptor(this.module);
     // Bind our import function
     this._instantiateBindImportFunctions(importObject);
 
     // Instantiate the module through the loader
-    const unboundExports = await asbindInstantiate(source, this.importObject);
+    this.loadedModule = await asbindInstantiate(this.module, this.importObject);
 
     // Bind our unbound exports
-    this._instantiateBindUnboundExports(unboundExports);
+    this._instantiateBindUnboundExports();
   }
 
   _instantiateSync(source, importObject) {
-    // Bind our import function
+    this.module = new WebAssembly.Module(source);
+    this._validate();
+    this.typeDescriptor = extractTypeDescriptor(this.module);
     this._instantiateBindImportFunctions(importObject);
 
-    // Instantiate the module through the loader
-    const unboundExports = asbindInstantiateSync(source, this.importObject);
-
-    // Bind our unbound exports
-    this._instantiateBindUnboundExports(unboundExports);
+    this.loadedModule = asbindInstantiateSync(this.module, this.importObject);
+    this._instantiateBindUnboundExports();
   }
 
   _instantiateBindImportFunctions(importObject) {
@@ -78,25 +122,18 @@ export default class AsbindInstance {
     );
   }
 
-  _instantiateBindUnboundExports(unboundExports) {
-    // Set our unbound exports
-    this.unboundExports = unboundExports;
-
+  _instantiateBindUnboundExports() {
     // Ensure that the AS Wasm was built with the as-bind entryfile
-    if (
-      !this.unboundExports.__asbind_entryfile_flag ||
-      this.unboundExports.__asbind_entryfile_flag === 0
-    ) {
-      throw new Error(
-        "as-bind: The instantiated AssemblyScript wasm module was not built with the as-bind entryfile. Please see the as-bind documentation (Quick Start), and rebuild your AssemblyScript wasm module."
-      );
+    if (this.loadedModule.exports?.__asbind_entryfile_flag?.value !== 1) {
     }
 
     // Wrap appropriate the appropriate export functions
+    const unboundExports = this.loadedModule.exports;
     this.exports = {};
-    Object.keys(this.unboundExports).forEach(unboundExportKey => {
+
+    Object.keys(unboundExports).forEach(unboundExportKey => {
       if (
-        typeof this.unboundExports[unboundExportKey] === "function" &&
+        typeof unboundExports[unboundExportKey] === "function" &&
         !isReservedExportKey(unboundExportKey)
       ) {
         // Wrap the export
@@ -105,66 +142,8 @@ export default class AsbindInstance {
           unboundExportKey
         );
       } else {
-        this.exports[unboundExportKey] = this.unboundExports[unboundExportKey];
-      }
-    });
-  }
-
-  enableExportFunctionTypeCaching() {
-    Object.keys(this.exports).forEach(exportKey => {
-      if (this.exports[exportKey]) {
-        this.exports[exportKey].shouldCacheTypes = true;
+        this.exports[unboundExportKey] = unboundExports[unboundExportKey];
       }
     });
   }
-
-  disableExportFunctionTypeCaching() {
-    Object.keys(this.exports).forEach(exportKey => {
-      if (this.exports[exportKey]) {
-        this.exports[exportKey].shouldCacheTypes = false;
-      }
-    });
-  }
-
-  enableExportFunctionUnsafeReturnValue() {
-    Object.keys(this.exports).forEach(exportKey => {
-      if (this.exports[exportKey]) {
-        this.exports[exportKey].unsafeReturnValue = true;
-      }
-    });
-  }
-
-  disableExportFunctionUnsafeReturnValue() {
-    Object.keys(this.exports).forEach(exportKey => {
-      if (this.exports[exportKey]) {
-        this.exports[exportKey].unsafeReturnValue = false;
-      }
-    });
-  }
-
-  enableImportFunctionTypeCaching() {
-    // Need to traverse the importObject and bind all import functions
-    traverseObjectAndRunCallbackForFunctions(
-      this.importObject,
-      [],
-      (baseObject, keys, baseObjectKey) => {
-        // Wrap the original key, but then expose a new key for the unbound import
-        let importFunction = baseObject[baseObjectKey];
-        importFunction.shouldCacheTypes = true;
-      }
-    );
-  }
-
-  disableImportFunctionTypeCaching() {
-    // Need to traverse the importObject and bind all import functions
-    traverseObjectAndRunCallbackForFunctions(
-      this.importObject,
-      [],
-      (baseObject, keys, baseObjectKey) => {
-        // Wrap the original key, but then expose a new key for the unbound import
-        let importFunction = baseObject[baseObjectKey];
-        importFunction.shouldCacheTypes = false;
-      }
-    );
-  }
 }