Forgot to add this file to repo.

modules/update-helper.js

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+/*
+Copyright 2020 Intel Corporation
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+var promise = require('promise');
+
+function start(updatePath)
+{
+    var ret = new promise(function (res, rej) { this._res = res; this._rej = rej; });
+    if (!require('zip-reader').isZip(updatePath)) { ret._res(); return (ret); }
+    ret._readpromise = require('zip-reader').read(updatePath);
+    ret._readpromise.then(function _updatehelper(zipped)
+    {
+        var p = new promise(function (res, rej) { this._res = res; this._rej = rej; });
+        if (zipped.files.length != 1)
+        {
+            p._rej('Unexpected contents in zip file');
+            zipped.close();
+        }
+        else
+        {
+            try
+            {
+                p.dest = require('fs').createWriteStream(updatePath + '_unzipped', { flags: 'wb' });
+            }
+            catch (e)
+            {
+                zipped.close();
+                p._rej(e);
+                return (p);
+            }
+            p.dest.prom = p;
+            p.dest.zipped = zipped;
+            p.dest.on('close', function () { this.zipped.close(); this.prom._res(); });
+            zipped.getStream(zipped.files[0]).pipe(p.dest);
+        }
+        return (p);
+    })
+    .then(function ()
+    {
+        try
+        {
+            require('fs').unlinkSync(updatePath);
+            require('fs').copyFileSync(updatePath + '_unzipped', updatePath);
+            require('fs').unlinkSync(updatePath + '_unzipped');
+        }
+        catch(e)
+        {
+            ret._rej(e);
+            return;
+        }
+        ret._res('done');
+    })
+    .catch(function (e) { ret._rej(e); });
+
+    return (ret);
+}
+
+module.exports = { start: start };