Binary tools cache & load from buffer

scripts/setup.js

@@ -13,11 +13,26 @@ if (fs.existsSync(util.bindir)) {
     process.exit(0);
 }
 
-var platform = process.platform + "-" + process.arch,
+var platform  = process.platform + "-" + process.arch,
     isWindows = /^win32/.test(platform),
-    temp = tmp.fileSync({ prefix: "wa-tools-" }),
-    file = fs.createWriteStream(temp.name),
-    archive = "tools-" + platform + (isWindows ? ".zip" : ".tar.gz");
+    temp      = tmp.fileSync({ prefix: "wa-tools-" }),
+    file      = fs.createWriteStream(temp.name),
+    archive   = "tools-" + platform + (isWindows ? ".zip" : ".tar.gz");
+
+function cachedDownload(callback) {
+  var tmpDir    = ['','tmp'].join(path.sep);
+  var cacheDir  = [tmpDir,'webassembly',pkg.tools].join(path.sep);
+  var cacheFile = [cacheDir,archive].join(path.sep);
+  if (fs.existsSync(cacheFile)) return callback(null,cacheFile);
+  if (!fs.existsSync(tmpDir)) return download(callback);
+  fs.mkdirSync(cacheDir, { recursive: true });
+
+  download(function(err, filename) {
+    if (err) return callback(err);
+    fs.copyFileSync(filename,cacheFile);
+    return callback(null,filename);
+  });
+}
 
 function download(callback) {
     var req = https.get("https://github.com/dcodeIO/webassembly/releases/download/" + pkg.tools + "/" + archive, res => {
@@ -62,7 +77,7 @@ function install(file, callback) {
 
 util.printLogo("Setup");
 process.stdout.write(chalk.white.bold("Downloading binaries for " + platform + " ...") + "\n");
-download(function(err, file) {
+cachedDownload(function(err, file) {
     if (err) {
         process.stderr.write("\n");
         throw err;

src/index.js

@@ -35,11 +35,13 @@ var getOwnPropertyNames = Object.getOwnPropertyNames;
 
 /**
  * Loads a WebAssembly.
- * @param {string} file File name
- * @param {LoadOptions} [options] Options
+ *
+ * @param {Buffer}       assembly   WebAssembly buffer
+ * @param {LoadOptions}  [options]  Options
+ *
  * @returns {Promise.<IModule>} Promise resolving to the instantiated module
  */
-function load(file, options) {
+function load_buffer(assembly, options) {
 
     /**
      * Options as used by {@link load}.
@@ -198,16 +200,15 @@ function load(file, options) {
     // Add default exit listeners if not explicitly imported
 
     if (!env._abort)
-        env._abort = errno => { throw Error("abnormal abort in " + file + ": " + errno); };
+        env._abort = errno => { throw Error("abnormal abort: " + errno); };
     if (!env._exit)
-        env._exit = code => { if (code) throw Error("abnormal exit in " + file + ": " + code); }
+        env._exit = code => { if (code) throw Error("abnormal exit: " + code); }
 
     // Finally, fetch the assembly and instantiate it
 
     env._grow = grow;
 
-    return (typeof fetch === "function" && fetch || fetch_node)(file)
-        .then(result => result.arrayBuffer())
+    return Promise.resolve(Buffer.from(assembly))
         .then(buffer => WebAssembly.instantiate(buffer, { env: env }))
         .then(module => {
             var instance = module.instance;
@@ -218,7 +219,21 @@ function load(file, options) {
         });
 }
 
-exports.load = load;
+exports.load_buffer = load_buffer;
+
+/**
+ * Loads a WebAssembly.
+ *
+ * @param {string}       filename   The file to load
+ * @param {LoadOptions}  [options]  Options
+ *
+ * @returns {Promise.<IModule>} Promise resolving to the instantiated module
+ */
+exports.load = function( filename, options ) {
+  return ('function' === typeof fetch && fetch || fetch_node)(filename)
+    .then(result => result.arrayBuffer())
+    .then(buffer => load_buffer(buffer, options));
+};
 
 // Internal fetch API polyfill for node that doesn't trigger webpack
 var fs;