[ADD] barcodes: onchange-like mechanism to react to scans in form view

For a model to use it, it must :
- Inherit barcodes.barcode_events_mixin and override on_barcode_scanned(self, barcode)
- Add <field name=barcode_scanned widget=barcode_handler/> to each form view that
  should listen to barcode events and trigger on_barcode_scanned.

The method on_barcode_scanned works just like an onchange.

addons/barcodes/__init__.py

@@ -1 +1,5 @@
+# -*- coding: utf-8 -*-
+
 import barcodes
+
+import models

addons/barcodes/models/__init__.py

@@ -0,0 +1,3 @@
+# -*- coding: utf-8 -*-
+
+import barcode_events_mixin

addons/barcodes/models/barcode_events_mixin.py

@@ -0,0 +1,24 @@
+# -*- coding: utf-8 -*-
+
+from openerp import models, fields, api
+
+class BarcodeEventsMixin(models.AbstractModel):
+    """ Mixin class for objects reacting when a barcode is scanned in their form views
+        which contains `<field name="_barcode_scanned" widget="barcode_handler"/>`.
+        Models using this mixin must implement the method on_barcode_scanned. It works
+        like an onchange and receives the scanned barcode in parameter.
+    """
+
+    _name = 'barcodes.barcode_events_mixin'
+
+    _barcode_scanned = fields.Char("Barcode Scanned", help="Value of the last barcode scanned.", store=False)
+
+    @api.onchange('_barcode_scanned')
+    def _on_barcode_scanned(self):
+        barcode = self._barcode_scanned
+        if barcode:
+            self._barcode_scanned = ""
+            return self.on_barcode_scanned(barcode)
+
+    def on_barcode_scanned(self, barcode):
+        raise NotImplementedError("In order to use barcodes.barcode_events_mixin, method on_barcode_scanned must be implemented")

addons/barcodes/static/src/js/form_view_barcode_handler.js

@@ -0,0 +1,79 @@
+odoo.define('barcodes.FormViewBarcodeHandler', function(require) {
+"use strict";
+
+var core = require('web.core');
+var utils = require('web.utils');
+var common = require('web.form_common');
+
+var _t = core._t;
+
+var FormViewBarcodeHandler = common.AbstractField.extend({
+
+    start: function() {
+        this._super();
+        this.form_view = this.field_manager;
+        core.bus.on('barcode_scanned', this, this.on_barcode_scanned);
+        // Hardcoded barcode actions
+        this.map_barcode_method = {
+            'O-CMD.NEW': _.bind(this.form_view.on_button_new, this.form_view),
+            'O-CMD.CANCEL': _.bind(this.form_view.on_button_cancel, this.form_view),
+            // FIXME: on_button_save shouldn't mix view and model concerns (it expects to be used as onclick handler)
+            'O-CMD.SAVE': _.bind(this.form_view.on_button_save, this.form_view, {target: $('.o_cp_buttons .o_form_button_save')}),
+        };
+        // Old design pager actions
+        if (this.form_view.execute_pager_action) {
+            this.map_barcode_method['O-CMD.PAGER-PREV'] = _.bind(this.form_view.execute_pager_action, this.form_view, 'previous');
+            this.map_barcode_method['O-CMD.PAGER-NEXT'] = _.bind(this.form_view.execute_pager_action, this.form_view, 'next');
+        // New design pager actions
+        } else if (this.form_view.pager) {
+            this.map_barcode_method['O-CMD.PAGER-PREV'] = _.bind(this.form_view.pager.previous, this.form_view.pager);
+            this.map_barcode_method['O-CMD.PAGER-NEXT'] = _.bind(this.form_view.pager.next, this.form_view.pager);
+        }
+    },
+    
+    // Let subclasses add custom behaviour before onchange
+    // Return false in order to proceed with the onchange, anything else to prevent it.
+    pre_onchange_hook: function(barcode) {
+        return false;
+    },
+
+    on_barcode_scanned: function(barcode) {
+        var self = this;
+        // Execute a harcoded action
+        var action = this.map_barcode_method[barcode];
+        if (typeof action === "function")
+            return $.when(action());
+        // Warn the user if form view is not editable
+        else if (this.form_view.get('actual_mode') === 'view')
+            this.do_warn(_t('Error : Document not editable'), _t('To modify this document, please first start edition.'));
+        else {
+            // Call hook method possibly implemented by subclass
+            $.when(this.pre_onchange_hook(barcode)).then(function(result) {
+                if (result !== false) {
+                    return result;
+                } else {
+                    // Wait for hypothetical ongoing onchange to finish
+                    self.form_view.onchanges_mutex.exec(function() {
+                        // A real onchange is triggered when a value actually changes (which can correspond
+                        // to a widget's blur event per example). Commit the value of fields before
+                        // programmatically triggering an onchange to be consistent with this.
+                        var mutex_commit_value = new utils.Mutex();
+                        _.each(self.form_view.fields, function(field) {
+                            mutex_commit_value.exec(_.bind(field.commit_value, field));
+                        });
+                        return mutex_commit_value.def.then(function(){
+                            // Trigger the barcode onchange
+                            self.set_value(barcode);
+                        });
+                    });
+                }
+            });
+        }
+    },
+});
+
+core.form_widget_registry.add('barcode_handler', FormViewBarcodeHandler);
+
+return FormViewBarcodeHandler;
+
+});

addons/barcodes/views/templates.xml

@@ -6,6 +6,7 @@
             <xpath expr="." position="inside">
                 <script type="text/javascript" src="/barcodes/static/src/js/barcode_parser.js"></script>
                 <script type="text/javascript" src="/barcodes/static/src/js/barcode_events.js"></script>
+                <script type="text/javascript" src="/barcodes/static/src/js/form_view_barcode_handler.js"></script>
             </xpath>
         </template>