[gnome-maps] shapeLayer: Load file contents asynchronously

[Marcus Lundblad <mlundblad src gnome org>]

commit ba125a91a0bb83c598009b777e111e94c0754109
Author: tyagi619 <tyagianubhav619 gmail com>
Date:   Mon Dec 14 19:02:07 2020 +0530

    shapeLayer: Load file contents asynchronously
    
    The loading of the file contents which is done from
    shapelayer.js uses load_contents() which is a synchronous
    call. Replaced load_contents() with load_contents_async()
    which is an async version of loading the file contents.
    
    Fixes #59

 src/mapView.js    | 19 ++++++++++++++++---
 src/shapeLayer.js | 27 ++++++++++++++++++---------
 2 files changed, 34 insertions(+), 12 deletions(-)
---
diff --git a/src/mapView.js b/src/mapView.js
index f6166599..f4e5e3d5 100644
--- a/src/mapView.js
+++ b/src/mapView.js
@@ -453,9 +453,24 @@ var MapView = GObject.registerClass({
         this._scale.visible = !this._scale.visible;
     }
 
+    _onShapeLoad(error, bbox, layer) {
+        if (error) {
+            let msg = _("Failed to open layer");
+            Utils.showDialog(msg, Gtk.MessageType.ERROR, this._mainWindow);
+        } else {
+            bbox.compose(layer.bbox);
+        }
+
+        this._remainingFilesToLoad--;
+        if (this._remainingFilesToLoad === 0) {
+            this.gotoBBox(bbox);
+        }
+    }
+
     openShapeLayers(files) {
         let bbox = new Champlain.BoundingBox();
         let ret = true;
+        this._remainingFilesToLoad = files.length;
         files.forEach((file) => {
             try {
                 let i = this._findShapeLayerIndex(file);
@@ -464,10 +479,9 @@ var MapView = GObject.registerClass({
                     layer = ShapeLayer.newFromFile(file, this);
                     if (!layer)
                         throw new Error(_("File type is not supported"));
-                    layer.load();
+                    layer.load(this._onShapeLoad.bind(this), bbox);
                     this.shapeLayerStore.append(layer);
                 }
-                bbox.compose(layer.bbox);
             } catch (e) {
                 Utils.debug(e);
                 let msg = _("Failed to open layer");
@@ -476,7 +490,6 @@ var MapView = GObject.registerClass({
             }
         });
 
-        this.gotoBBox(bbox);
         return ret;
     }
 
diff --git a/src/shapeLayer.js b/src/shapeLayer.js
index 1b9b00ae..7d42c9b4 100644
--- a/src/shapeLayer.js
+++ b/src/shapeLayer.js
@@ -22,6 +22,7 @@ const Gio = imports.gi.Gio;
 const GObject = imports.gi.GObject;
 
 const GeoJSONShapeLayer = imports.geoJSONShapeLayer;
+const Utils = imports.utils;
 
 var SUPPORTED_TYPES = [];
 
@@ -84,17 +85,25 @@ var ShapeLayer = GObject.registerClass({
         return this.filename.replace(/\.[^\.]+$/, '');
     }
 
-    load() {
-        let [status, buffer] = this.file.load_contents(null);
-        this._fileContents = buffer;
-        if (!status)
-            throw new Error(_("failed to load file"));
-        this._parseContent();
-        this._mapView.view.add_layer(this._markerLayer);
-        this._mapView.view.add_overlay_source(this._mapSource, 255);
+    load(callback, bbox) {
+        this.file.load_contents_async(null, (sourceObject, result) => {
+            let error = false;
+            try {
+                let [status, buffer] = this.file.load_contents_finish(result);
+                this._fileContents = buffer;
+                if (!status)
+                    throw new Error(_("failed to load file"));
+                this._parseContent();
+                this._mapView.view.add_layer(this._markerLayer);
+                this._mapView.view.add_overlay_source(this._mapSource, 255);
+            } catch (e) {
+                Utils.debug(e);
+                error = true;
+            }
+            callback(error, bbox, this);
+        });
     }
 
-
     _parseContent() {
         /* Unimplemented */
     }