From b817e0f58d6b62a6d8fc445be0e1bfaf1ef29d03 Mon Sep 17 00:00:00 2001
From: Alexander Shalamov <alexander.shalamov@mapbox.com>
Date: Thu, 19 Mar 2020 23:15:46 +0200
Subject: Use custom deleter for snapshotter

---
 .../android/src/snapshotter/map_snapshotter.cpp    | 46 ++++++++++++----------
 .../android/src/snapshotter/map_snapshotter.hpp    | 14 +++++--
 2 files changed, 35 insertions(+), 25 deletions(-)

diff --git a/platform/android/src/snapshotter/map_snapshotter.cpp b/platform/android/src/snapshotter/map_snapshotter.cpp
index 115c455a94..844d6481da 100644
--- a/platform/android/src/snapshotter/map_snapshotter.cpp
+++ b/platform/android/src/snapshotter/map_snapshotter.cpp
@@ -6,12 +6,28 @@
 #include <mbgl/util/string.hpp>
 #include <mbgl/actor/scheduler.hpp>
 
+#include <mapbox/weak.hpp>
+
 #include "../attach_env.hpp"
 #include "map_snapshot.hpp"
 
 namespace mbgl {
 namespace android {
 
+MapSnapshotter::DeleteOnThread::DeleteOnThread() = default;
+MapSnapshotter::DeleteOnThread::DeleteOnThread(mapbox::base::WeakPtr<mbgl::Scheduler> weakScheduler_) : weakScheduler(weakScheduler_) {}
+
+void MapSnapshotter::DeleteOnThread::operator()(mbgl::MapSnapshotter* p) const {
+    auto guard = weakScheduler.lock();
+    if (weakScheduler && weakScheduler.get() != mbgl::Scheduler::GetCurrent()) {
+        weakScheduler->schedule([ptr = std::shared_ptr<mbgl::MapSnapshotter>(p, DeleteOnThread(weakScheduler))] {
+            (void)ptr;
+        });
+    } else {
+        delete p;
+    }
+}
+
 MapSnapshotter::MapSnapshotter(jni::JNIEnv& _env,
                                const jni::Object<MapSnapshotter>& _obj,
                                const jni::Object<FileSource>& _jFileSource,
@@ -33,19 +49,19 @@ MapSnapshotter::MapSnapshotter(jni::JNIEnv& _env,
         return;
     }
 
-    weakScheduler = mbgl::Scheduler::GetCurrent()->makeWeakPtr();
-
     jFileSource = FileSource::getNativePeer(_env, _jFileSource);
     auto size = mbgl::Size { static_cast<uint32_t>(width), static_cast<uint32_t>(height) };
 
     showLogo = _showLogo;
+
     // Create the core snapshotter
-    snapshotter = std::make_unique<mbgl::MapSnapshotter>(
-        size,
-        pixelRatio,
-        mbgl::android::FileSource::getSharedResourceOptions(_env, _jFileSource),
-        *this,
-        _localIdeographFontFamily ? jni::Make<std::string>(_env, _localIdeographFontFamily) : optional<std::string>{});
+    snapshotter = std::unique_ptr<mbgl::MapSnapshotter, DeleteOnThread>(new mbgl::MapSnapshotter(
+            size,
+            pixelRatio,
+            mbgl::android::FileSource::getSharedResourceOptions(_env, _jFileSource),
+            *this,
+            _localIdeographFontFamily ? jni::Make<std::string>(_env, _localIdeographFontFamily) : optional<std::string>{}),
+                    DeleteOnThread(mbgl::Scheduler::GetCurrent()->makeWeakPtr()));
 
     if (position) {
         snapshotter->setCameraOptions(CameraPosition::getCameraOptions(_env, position, pixelRatio));
@@ -62,19 +78,7 @@ MapSnapshotter::MapSnapshotter(jni::JNIEnv& _env,
     }
 }
 
-MapSnapshotter::~MapSnapshotter() {
-    auto guard = weakScheduler.lock();
-    if (weakScheduler && weakScheduler.get() != mbgl::Scheduler::GetCurrent()) {
-        snapshotter->cancel();
-        std::shared_ptr<mbgl::MapSnapshotter> shared = std::move(snapshotter);
-        weakScheduler->schedule([s = std::move(shared)] {
-            (void)s;
-        });
-    } else {
-        snapshotter.reset();
-    }
-    vm = nullptr;
-}
+MapSnapshotter::~MapSnapshotter() = default;
 
 void MapSnapshotter::start(JNIEnv& env) {
     MBGL_VERIFY_THREAD(tid);
diff --git a/platform/android/src/snapshotter/map_snapshotter.hpp b/platform/android/src/snapshotter/map_snapshotter.hpp
index 1da4f8275b..e6f543649f 100644
--- a/platform/android/src/snapshotter/map_snapshotter.hpp
+++ b/platform/android/src/snapshotter/map_snapshotter.hpp
@@ -3,9 +3,7 @@
 #include <jni/jni.hpp>
 #include <mbgl/map/map_snapshotter.hpp>
 #include <mbgl/util/util.hpp>
-
 #include <memory>
-#include <mapbox/weak.hpp>
 
 #include "../file_source.hpp"
 #include "../geometry/lat_lng_bounds.hpp"
@@ -64,6 +62,15 @@ public:
     void onDidFinishLoadingStyle() override;
     void onStyleImageMissing(const std::string&) override;
 
+private:
+    struct DeleteOnThread {
+        DeleteOnThread();
+        explicit DeleteOnThread(mapbox::base::WeakPtr<mbgl::Scheduler>);
+        void operator()(mbgl::MapSnapshotter* p) const;
+    private:
+        mapbox::base::WeakPtr<mbgl::Scheduler> weakScheduler;
+    };
+
 private:
     MBGL_STORE_THREAD(tid);
 
@@ -77,8 +84,7 @@ private:
     void activateFilesource(JNIEnv&);
     void deactivateFilesource(JNIEnv&);
     bool activatedFilesource = false;
-    std::unique_ptr<mbgl::MapSnapshotter> snapshotter;
-    mapbox::base::WeakPtr<mbgl::Scheduler> weakScheduler;
+    std::unique_ptr<mbgl::MapSnapshotter, DeleteOnThread> snapshotter;
 };
 
 } // namespace android
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