From bda6ed26c65b541b0633fcdf824f2baef30aa0cc Mon Sep 17 00:00:00 2001
From: Ivo van Dongen <info@ivovandongen.nl>
Date: Fri, 15 Sep 2017 18:03:04 +0300
Subject: [core] send signal to RenderCustomLayer when gl context has been lost

- Prevents cleaning up of GL resources that no longer exist, resulting in a crash
---
 include/mbgl/renderer/renderer.hpp               |  2 ++
 src/mbgl/renderer/layers/render_custom_layer.cpp |  2 +-
 src/mbgl/renderer/layers/render_custom_layer.hpp |  5 +++++
 src/mbgl/renderer/renderer.cpp                   |  4 ++++
 src/mbgl/renderer/renderer_impl.cpp              | 11 +++++++++++
 src/mbgl/renderer/renderer_impl.hpp              |  6 ++++++
 6 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/include/mbgl/renderer/renderer.hpp b/include/mbgl/renderer/renderer.hpp
index 95828a1b79..be8abb2c29 100644
--- a/include/mbgl/renderer/renderer.hpp
+++ b/include/mbgl/renderer/renderer.hpp
@@ -28,6 +28,8 @@ public:
              const optional<std::string> programCacheDir = {});
     ~Renderer();
 
+    void markContextLost();
+
     void setObserver(RendererObserver*);
 
     void render(const UpdateParameters&);
diff --git a/src/mbgl/renderer/layers/render_custom_layer.cpp b/src/mbgl/renderer/layers/render_custom_layer.cpp
index ae0c4b026b..3d19f5ef46 100644
--- a/src/mbgl/renderer/layers/render_custom_layer.cpp
+++ b/src/mbgl/renderer/layers/render_custom_layer.cpp
@@ -16,7 +16,7 @@ RenderCustomLayer::RenderCustomLayer(Immutable<style::CustomLayer::Impl> _impl)
 
 RenderCustomLayer::~RenderCustomLayer() {
     assert(BackendScope::exists());
-    if (initialized && impl().deinitializeFn) {
+    if (initialized && !contextDestroyed && impl().deinitializeFn) {
         impl().deinitializeFn(impl().context);
     }
 }
diff --git a/src/mbgl/renderer/layers/render_custom_layer.hpp b/src/mbgl/renderer/layers/render_custom_layer.hpp
index d8e9d93811..32ed9da8da 100644
--- a/src/mbgl/renderer/layers/render_custom_layer.hpp
+++ b/src/mbgl/renderer/layers/render_custom_layer.hpp
@@ -19,8 +19,13 @@ public:
 
     const style::CustomLayer::Impl& impl() const;
 
+    void markContextDestroyed() {
+        contextDestroyed = true;
+    };
+
 private:
     bool initialized = false;
+    bool contextDestroyed = false;
 };
 
 template <>
diff --git a/src/mbgl/renderer/renderer.cpp b/src/mbgl/renderer/renderer.cpp
index a106d6c5fa..e915f5e146 100644
--- a/src/mbgl/renderer/renderer.cpp
+++ b/src/mbgl/renderer/renderer.cpp
@@ -20,6 +20,10 @@ Renderer::~Renderer() {
     impl.reset();
 }
 
+void Renderer::markContextLost() {
+    impl->markContextLost();
+}
+
 void Renderer::setObserver(RendererObserver* observer) {
     impl->setObserver(observer);
 }
diff --git a/src/mbgl/renderer/renderer_impl.cpp b/src/mbgl/renderer/renderer_impl.cpp
index c45295b693..1a828b80a3 100644
--- a/src/mbgl/renderer/renderer_impl.cpp
+++ b/src/mbgl/renderer/renderer_impl.cpp
@@ -62,6 +62,17 @@ Renderer::Impl::Impl(RendererBackend& backend_,
 
 Renderer::Impl::~Impl() {
     assert(BackendScope::exists());
+
+    if (contextLost) {
+        // Signal all RenderCustomLayers that the context was lost
+        // before cleaning up
+        for (const auto& entry : renderLayers) {
+            RenderLayer& layer = *entry.second;
+            if (layer.is<RenderCustomLayer>()) {
+                layer.as<RenderCustomLayer>()->markContextDestroyed();
+            }
+        }
+    }
 };
 
 void Renderer::Impl::setObserver(RendererObserver* observer_) {
diff --git a/src/mbgl/renderer/renderer_impl.hpp b/src/mbgl/renderer/renderer_impl.hpp
index 8bdb472442..30e7f70722 100644
--- a/src/mbgl/renderer/renderer_impl.hpp
+++ b/src/mbgl/renderer/renderer_impl.hpp
@@ -39,6 +39,10 @@ public:
          const optional<std::string> programCacheDir);
     ~Impl() final;
 
+    void markContextLost() {
+        contextLost = true;
+    };
+
     void setObserver(RendererObserver*);
 
     void render(const UpdateParameters&);
@@ -100,6 +104,8 @@ private:
     std::unordered_map<std::string, std::unique_ptr<RenderSource>> renderSources;
     std::unordered_map<std::string, std::unique_ptr<RenderLayer>> renderLayers;
     RenderLight renderLight;
+
+    bool contextLost = false;
 };
 
 } // namespace mbgl
-- 
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