[ADD] stock_barcode: field widget with barcodes scan + manual input

Barcodes are detected by catching keypresses. When a keypress is not
part of a barcode, it is 'released' by forging a keypress event.
For security reasons, a non-native keypress doesn't trigger the native
input mechanism. So in order to make both barcode-scanning and manual
keypresses work in a field, it is necessary to have a handler listen
to the 'false' keypresses and simulate the native input behaviour.

addons/barcodes/static/src/js/field_float_scannable.js

@@ -0,0 +1,46 @@
+odoo.define('barcodes.FieldFloatScannable', function(require) {
+"use strict";
+
+var core = require('web.core');
+var form_widgets = require('web.form_widgets');
+
+// Field in which the user can both type normally and scan barcodes
+
+var FieldFloatScannable = form_widgets.FieldFloat.extend({
+    events: {
+        // The barcode_events component intercepts keypresses and releases them when it
+        // appears they are not part of a barcode. But since released keypresses don't
+        // trigger native behaviour (like characters input), we must simulate it.
+        'keypress': 'simulateKeypress',
+    },
+
+    simulateKeypress: function (e) {
+        var character = String.fromCharCode(e.which);
+        var current_str = e.target.value;
+        var str_before_carret = current_str.substring(0, e.target.selectionStart);
+        var str_after_carret = current_str.substring(e.target.selectionEnd);
+        e.target.value = str_before_carret + character + str_after_carret;
+        var new_carret_index = str_before_carret.length + character.length;
+        e.target.setSelectionRange(new_carret_index, new_carret_index);
+        // Note: FieldChar (that FieldFloat extends) calls store_dom_value upon change
+        // event, which is triggered when the input loses focus and its internal dirty
+        // flag is set. But here, we directly modify the value property of the input,
+        // which doesn't set the dirty flag. So we could call store_dom_value upon blur.
+        // But we also want the DOM value to be stored when a barcode_event occurs and
+        // triggers an onchange. We could listen to barcode_event in order to call
+        // store_dom_value, but that would have to happen before the onchange is triggered.
+        // So the safest method is still to store the value each time it changes.
+        // This long explanation is here to avoid having to do the thinking all over agan
+        // in case this strategy doesn't work / breaks. 
+        // TL;DR Safest way not to lose the value when a barcode scan triggers an onchange.
+        this.store_dom_value();
+    },
+});
+
+core.form_widget_registry.add('field_float_scannable', FieldFloatScannable);
+
+return {
+    FieldFloatScannable: FieldFloatScannable,
+};
+
+});

addons/barcodes/views/templates.xml

@@ -9,6 +9,7 @@
                 <script type="text/javascript" src="/barcodes/static/src/js/barcode_handler_mixin.js"></script>
                 <script type="text/javascript" src="/barcodes/static/src/js/form_view_barcode_handler.js"></script>
                 <script type="text/javascript" src="/barcodes/static/src/js/inherited_form_widget_button.js"></script>
+                <script type="text/javascript" src="/barcodes/static/src/js/field_float_scannable.js"></script>
             </xpath>
         </template>
 

addons/web/static/src/js/views/form_widgets.js

@@ -1663,6 +1663,7 @@ core.form_tag_registry.add('button', WidgetButton);
 
 return {
     FieldChar: FieldChar,
+    FieldFloat: FieldFloat,
     FieldMonetary: FieldMonetary,
     WidgetButton: WidgetButton
 };