Merge pull request #125 from mapbox/failed-requests

Handle failed requests

src/node_map.cpp

@@ -204,10 +204,15 @@ void NodeMap::startRender(std::unique_ptr<NodeMap::RenderOptions> options) {
     map.setLatLngZoom(mbgl::LatLng(options->latitude, options->longitude), options->zoom);
     map.setBearing(options->bearing);
 
-    map.renderStill([this](std::unique_ptr<const mbgl::StillImage> result) {
-        assert(!image);
-        image = std::move(result);
-        uv_async_send(async);
+    map.renderStill([this](const std::exception_ptr eptr, std::unique_ptr<const mbgl::StillImage> result) {
+        if (eptr) {
+            error = std::move(eptr);
+            uv_async_send(async);
+        } else {
+            assert(!image);
+            image = std::move(result);
+            uv_async_send(async);
+        }
     });
 
     // Retain this object, otherwise it might get destructed before we are finished rendering the
@@ -238,7 +243,16 @@ void NodeMap::renderFinished() {
     assert(!callback);
     assert(!image);
 
-    if (img) {
+    if (error) {
+        // This must be empty to be prepared for the next render call.
+        error = nullptr;
+        assert(!error);
+
+        v8::Local<v8::Value> argv[] = {
+            NanError("Error rendering image")
+        };
+        cb->Call(1, argv);
+    } else if (img) {
         auto result = NanNew<v8::Object>();
         result->Set(NanNew("width"), NanNew(img->width));
         result->Set(NanNew("height"), NanNew(img->height));

src/node_map.hpp

@@ -50,6 +50,7 @@ private:
     NodeFileSource &fs;
     mbgl::Map map;
 
+    std::exception_ptr error;
     std::unique_ptr<const mbgl::StillImage> image;
     std::unique_ptr<NanCallback> callback;
 

test/js/map.test.js

@@ -157,7 +157,6 @@ test('Map', function(t) {
         fileSource.request = function(req) {
             fs.readFile(path.join('test', req.url), function(err, data) {
                 req.respond(err, { data: data });
-                t.error(err);
             });
         };
         fileSource.cancel = function() {};
@@ -199,6 +198,17 @@ test('Map', function(t) {
             });
         });
 
+        t.test('returns an error', function(t) {
+            setup(fileSource, function(map) {
+                map.load(style);
+                map.render({ zoom: 1 }, function(err, data) {
+                    t.ok(err);
+                    t.equal(err.message, 'Error rendering image');
+                    t.end();
+                });
+            });
+        });
+
         t.test('returns an image', function(t) {
             setup(fileSource, function(map) {
                 map.load(style);