From f5dc7e2c85436877606af46a011c2fba112185a9 Mon Sep 17 00:00:00 2001
From: dec05eba <dec05eba@protonmail.com>
Date: Sun, 18 Oct 2020 06:54:18 +0200
Subject: Fix potential crash in thumbnail loader: 2

---
 include/AsyncImageLoader.hpp |  6 ++----
 src/AsyncImageLoader.cpp     | 24 ++++++++----------------
 src/QuickMedia.cpp           |  1 -
 3 files changed, 10 insertions(+), 21 deletions(-)

diff --git a/include/AsyncImageLoader.hpp b/include/AsyncImageLoader.hpp
index fe8d52a..fa32971 100644
--- a/include/AsyncImageLoader.hpp
+++ b/include/AsyncImageLoader.hpp
@@ -4,7 +4,7 @@
 #include <SFML/System/Vector2.hpp>
 #include <SFML/Graphics/Texture.hpp>
 #include <memory>
-#include <future>
+#include <thread>
 
 namespace QuickMedia {
     enum class LoadingState {
@@ -23,15 +23,13 @@ namespace QuickMedia {
 
     class AsyncImageLoader {
     public:
-        ~AsyncImageLoader();
         // Returns false if the image loader is already loading an image. In that case, this function should be called again later.
         // set |resize_target_size| to {0, 0} to disable resizing.
         // |thumbnail_data.loading_state| has to be LoadingState::NOT_LOADED when calling this!
         // Note: this method is not thread-safe
         bool load_thumbnail(const std::string &url, bool local, sf::Vector2i resize_target_size, bool use_tor, std::shared_ptr<ThumbnailData> thumbnail_data);
-        void update();
     private:
         bool loading_image = false;
-        std::future<void> load_image_future;
+        std::thread load_image_thread;
     };
 }
\ No newline at end of file
diff --git a/src/AsyncImageLoader.cpp b/src/AsyncImageLoader.cpp
index fb864c2..8f771e7 100644
--- a/src/AsyncImageLoader.cpp
+++ b/src/AsyncImageLoader.cpp
@@ -70,16 +70,8 @@ namespace QuickMedia {
         return "";
     }
 
-    // TODO: Remove and use std::thread and detach instead of std::async
-    AsyncImageLoader::~AsyncImageLoader() {
-        if(load_image_future.valid())
-            load_image_future.get();
-    }
-
     // TODO: Run in 5 different threads, and add download_to_file(_cache) to reduce memory usage in each (use -O curl option)
     bool AsyncImageLoader::load_thumbnail(const std::string &url, bool local, sf::Vector2i resize_target_size, bool use_tor, std::shared_ptr<ThumbnailData> thumbnail_data) {
-        update();
-
         if(loading_image)
             return false;
 
@@ -95,7 +87,8 @@ namespace QuickMedia {
             return true;
         }
 
-        load_image_future = std::async(std::launch::async, [url, local, resize_target_size, thumbnail_data, use_tor]() mutable {
+        // TODO: Keep the thread running and use conditional variable instead to sleep until a new image should be loaded. Same in ImageViewer.
+        load_image_thread = std::thread([this, url, local, resize_target_size, thumbnail_data, use_tor]() mutable {
             // TODO: Use sha256 instead of base64_url encoding
             Path thumbnail_path = get_cache_dir().join("thumbnails").join(base64_url::encode(url));
 
@@ -103,17 +96,20 @@ namespace QuickMedia {
             if(thumbnail_data->image->loadFromFile(thumbnail_path.data)) {
                 fprintf(stderr, "Loaded %s from thumbnail cache\n", url.c_str());
                 thumbnail_data->loading_state = LoadingState::FINISHED_LOADING;
+                loading_image = false;
                 return;
             } else {
                 if(local) {
                     if(!thumbnail_data->image->loadFromFile(url)) {
                         thumbnail_data->loading_state = LoadingState::FINISHED_LOADING;
+                        loading_image = false;
                         return;
                     }
                 } else {
                     std::string texture_data;
                     if(download_to_string_cache(url, texture_data, {}, use_tor, true) != DownloadResult::OK || !thumbnail_data->image->loadFromMemory(texture_data.data(), texture_data.size())) {
                         thumbnail_data->loading_state = LoadingState::FINISHED_LOADING;
+                        loading_image = false;
                         return;
                     }
                 }
@@ -127,21 +123,17 @@ namespace QuickMedia {
                     thumbnail_data->image = std::move(destination_image);
                     save_image_as_thumbnail_atomic(*thumbnail_data->image, thumbnail_path, get_ext(url));
                     thumbnail_data->loading_state = LoadingState::FINISHED_LOADING;
+                    loading_image = false;
                     return;
                 }
             }
 
             thumbnail_data->loading_state = LoadingState::FINISHED_LOADING;
+            loading_image = false;
             return;
         });
+        load_image_thread.detach();
 
         return true;
     }
-
-    void AsyncImageLoader::update() {
-        if(loading_image && load_image_future.valid() && load_image_future.wait_for(std::chrono::seconds(0)) == std::future_status::ready) {
-            load_image_future.get();
-            loading_image = false;
-        }
-    }
 }
\ No newline at end of file
diff --git a/src/QuickMedia.cpp b/src/QuickMedia.cpp
index 13f7db9..070b8fe 100644
--- a/src/QuickMedia.cpp
+++ b/src/QuickMedia.cpp
@@ -3742,7 +3742,6 @@ namespace QuickMedia {
                 ++it;
             }
 
-            async_image_loader.update();
             if(current_room_body_data && room_avatar_thumbnail_data->loading_state == LoadingState::NOT_LOADED)
                 async_image_loader.load_thumbnail(current_room_body_data->body_item->thumbnail_url, false, sf::Vector2i(32, 32), use_tor, room_avatar_thumbnail_data);
 
-- 
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