Convert readAsync to return a promise. NFC (#22035)

Followup to #22026

Since all the call sites are mostly promise based it makes logical
sense to return a promise here.

Author: sbc100

ChangeLog.md

@@ -3119,19 +3119,22 @@ addToLibrary({
   $asyncLoad__docs: '/** @param {boolean=} noRunDep */',
   $asyncLoad: (url, onload, onerror, noRunDep) => {
     var dep = !noRunDep ? getUniqueRunDependency(`al ${url}`) : '';
-    readAsync(url, (arrayBuffer) => {
+    readAsync(url).then(
+      (arrayBuffer) => {
 #if ASSERTIONS
-      assert(arrayBuffer, `Loading data file "${url}" failed (no arrayBuffer).`);
+        assert(arrayBuffer, `Loading data file "${url}" failed (no arrayBuffer).`);
 #endif
-      onload(new Uint8Array(arrayBuffer));
-      if (dep) removeRunDependency(dep);
-    }, (event) => {
-      if (onerror) {
-        onerror();
-      } else {
-        throw `Loading data file "${url}" failed.`;
+        onload(new Uint8Array(arrayBuffer));
+        if (dep) removeRunDependency(dep);
+      },
+      (err) => {
+        if (onerror) {
+          onerror();
+        } else {
+          throw `Loading data file "${url}" failed.`;
+        }
       }
-    });
+    );
     if (dep) addRunDependency(dep);
   },
 

src/library.js

@@ -802,10 +802,10 @@ var LibraryBrowser = {
 
 #if ENVIRONMENT_MAY_BE_NODE && DYNAMIC_EXECUTION
     if (ENVIRONMENT_IS_NODE) {
-      readAsync(url, (data) => {
+      readAsync(url, false).then((data) => {
         eval(data);
         loadDone();
-      }, loadError, false);
+      }, loadError);
       return;
     }
 #endif

src/library_browser.js

@@ -22,11 +22,13 @@ readBinary = (filename) => {
   return ret;
 };
 
-readAsync = (filename, onload, onerror, binary = true) => {
+readAsync = (filename, binary = true) => {
   // See the comment in the `read_` function.
   filename = isFileURI(filename) ? new URL(filename) : nodePath.normalize(filename);
-  fs.readFile(filename, binary ? undefined : 'utf8', (err, data) => {
-    if (err) onerror(err);
-    else onload(binary ? data.buffer : data);
+  return new Promise((resolve, reject) => {
+    fs.readFile(filename, binary ? undefined : 'utf8', (err, data) => {
+      if (err) reject(err);
+      else resolve(binary ? data.buffer : data);
+    });
   });
 };

src/node_shell_read.js

@@ -648,15 +648,12 @@ function getBinaryPromise(binaryFile) {
       || isDataURI(binaryFile)
 #endif
       ) {
-    // Fetch the binary use readAsync
-    return new Promise((resolve, reject) => {
-      readAsync(binaryFile,
-        (response) => resolve(new Uint8Array(/** @type{!ArrayBuffer} */(response))),
-        (error) => {
-          try { resolve(getBinarySync(binaryFile)); }
-          catch (e) { reject(e); }
-        });
-    });
+    // Fetch the binary using readAsync
+    return readAsync(binaryFile).then(
+      (response) => new Uint8Array(/** @type{!ArrayBuffer} */(response)),
+      // Fall back to getBinarySync if readAsync fails
+      () => getBinarySync(binaryFile)
+    );
   }
 #endif
 

src/preamble.js

@@ -324,8 +324,10 @@ if (ENVIRONMENT_IS_SHELL) {
     return data;
   };
 
-  readAsync = (f, onload, onerror) => {
-    setTimeout(() => onload(readBinary(f)));
+  readAsync = (f) => {
+    return new Promise((resolve, reject) => {
+      setTimeout(() => resolve(readBinary(f)));
+    });
   };
 
   if (typeof clearTimeout == 'undefined') {

src/shell.js

@@ -21,36 +21,35 @@
     };
   }
 
-  readAsync = (url, onload, onerror) => {
+  readAsync = (url) => {
 #if ENVIRONMENT_MAY_BE_WEBVIEW
     // Fetch has some additional restrictions over XHR, like it can't be used on a file:// url.
     // See https://github.com/github/fetch/pull/92#issuecomment-140665932
     // Cordova or Electron apps are typically loaded from a file:// url.
     // So use XHR on webview if URL is a file URL.
     if (isFileURI(url)) {
-      var xhr = new XMLHttpRequest();
-      xhr.open('GET', url, true);
-      xhr.responseType = 'arraybuffer';
-      xhr.onload = () => {
-        if (xhr.status == 200 || (xhr.status == 0 && xhr.response)) { // file URLs can return 0
-          onload(xhr.response);
-          return;
-        }
-        onerror();
-      };
-      xhr.onerror = onerror;
-      xhr.send(null);
-      return;
+      return new Promise((reject, resolve) => {
+        var xhr = new XMLHttpRequest();
+        xhr.open('GET', url, true);
+        xhr.responseType = 'arraybuffer';
+        xhr.onload = () => {
+          if (xhr.status == 200 || (xhr.status == 0 && xhr.response)) { // file URLs can return 0
+            resolve(xhr.response);
+          }
+          reject(xhr.status);
+        };
+        xhr.onerror = reject;
+        xhr.send(null);
+      });
     }
 #elif ASSERTIONS
     assert(!isFileURI(url), "readAsync does not work with file:// URLs");
 #endif
-    fetch(url, {{{ makeModuleReceiveExpr('fetchSettings', "{ credentials: 'same-origin' }") }}})
-    .then((response) => {
-      if (response.ok) {
-        return response.arrayBuffer();
-      }
-      return Promise.reject(new Error(response.status + ' : ' + response.url));
-    })
-    .then(onload, onerror)
+    return fetch(url, {{{ makeModuleReceiveExpr('fetchSettings', "{ credentials: 'same-origin' }") }}})
+      .then((response) => {
+        if (response.ok) {
+          return response.arrayBuffer();
+        }
+        return Promise.reject(new Error(response.status + ' : ' + response.url));
+      })
   };

src/web_or_worker_shell_read.js

@@ -1 +1 @@
-9817
+9804

test/other/metadce/test_metadce_cxx_ctors1.gzsize

@@ -1 +1 @@
-24102
+24088

test/other/metadce/test_metadce_cxx_ctors1.jssize

@@ -1 +1 @@
-9801
+9788