[Qt] Implement updateSource

It will create or update a source. Right now only GeoJSON sources are
mutable and can be updated using this method.

3 files changed, 28 insertions, 3 deletions

diff --git a/platform/qt/include/qmapboxgl.hpp b/platform/qt/include/qmapboxgl.hpp
index 2361b78f8f..8a77bbffab 100644
--- a/platform/qt/include/qmapboxgl.hpp
+++ b/platform/qt/include/qmapboxgl.hpp
@@ -186,6 +186,7 @@ public:
     QMargins margins() const;
 
     void addSource(const QString &sourceID, const QVariantMap& params);
+    void updateSource(const QString &sourceID, const QVariantMap& params);
     void removeSource(const QString &sourceID);
 
     void addImage(const QString &name, const QImage &sprite);
diff --git a/platform/qt/src/qmapboxgl.cpp b/platform/qt/src/qmapboxgl.cpp
index 75f5d112ca..ae4c028eed 100644
--- a/platform/qt/src/qmapboxgl.cpp
+++ b/platform/qt/src/qmapboxgl.cpp
@@ -13,6 +13,7 @@
 #include <mbgl/style/conversion/layer.hpp>
 #include <mbgl/style/conversion/source.hpp>
 #include <mbgl/style/layers/custom_layer.hpp>
+#include <mbgl/style/sources/geojson_source.hpp>
 #include <mbgl/style/transition_options.hpp>
 #include <mbgl/sprite/sprite_image.hpp>
 #include <mbgl/storage/network_status.hpp>
@@ -694,8 +695,6 @@ void QMapboxGL::addSource(const QString &sourceID, const QVariantMap &params)
     using namespace mbgl::style;
     using namespace mbgl::style::conversion;
 
-    removeSource(sourceID);
-
     Result<std::unique_ptr<Source>> source = convert<std::unique_ptr<Source>>(QVariant(params), sourceID.toStdString());
     if (!source) {
         qWarning() << "Unable to add source:" << source.error().message.c_str();
@@ -705,6 +704,31 @@ void QMapboxGL::addSource(const QString &sourceID, const QVariantMap &params)
     d_ptr->mapObj->addSource(std::move(*source));
 }
 
+void QMapboxGL::updateSource(const QString &sourceID, const QVariantMap &params)
+{
+    using namespace mbgl::style;
+    using namespace mbgl::style::conversion;
+
+    auto source = d_ptr->mapObj->getSource(sourceID.toStdString());
+    if (!source) {
+        addSource(sourceID, params);
+        return;
+    }
+
+    auto sourceGeoJSON = source->as<GeoJSONSource>();
+    if (!sourceGeoJSON) {
+        qWarning() << "Unable to update source: only GeoJSON sources are mutable.";
+        return;
+    }
+
+    if (params.contains("data")) {
+        auto result = convertGeoJSON(params["data"]);
+        if (result) {
+            sourceGeoJSON->setGeoJSON(*result);
+        }
+    }
+}
+
 void QMapboxGL::removeSource(const QString& sourceID)
 {
     auto sourceIDStdString = sourceID.toStdString();
diff --git a/platform/qt/src/qquickmapboxglrenderer.cpp b/platform/qt/src/qquickmapboxglrenderer.cpp
index 903e1c0b05..880d7b2e40 100644
--- a/platform/qt/src/qquickmapboxglrenderer.cpp
+++ b/platform/qt/src/qquickmapboxglrenderer.cpp
@@ -88,7 +88,7 @@ void QQuickMapboxGLRenderer::synchronize(QQuickFramebufferObject *item)
     }
 
     for (const auto& change : quickMap->m_sourceChanges) {
-        m_map->addSource(change.value("id").toString(), change);
+        m_map->updateSource(change.value("id").toString(), change);
     }
     quickMap->m_sourceChanges.clear();