From 9866713ba916f9768edca02c61ed5ec580bd9557 Mon Sep 17 00:00:00 2001
From: dec05eba <dec05eba@protonmail.com>
Date: Sun, 27 Sep 2020 01:08:34 +0200
Subject: Reduce scroll cpu usage from 10% to 1-2% by load image files in
 another thread but load the texture in the main thread

---
 src/QuickMedia.cpp | 47 ++++++++++++++++++++++++++++++-----------------
 1 file changed, 30 insertions(+), 17 deletions(-)

(limited to 'src/QuickMedia.cpp')

diff --git a/src/QuickMedia.cpp b/src/QuickMedia.cpp
index 6293e52..05b65ea 100644
--- a/src/QuickMedia.cpp
+++ b/src/QuickMedia.cpp
@@ -2695,14 +2695,14 @@ namespace QuickMedia {
         std::future<bool> captcha_request_future;
         std::future<bool> captcha_post_solution_future;
         std::future<bool> post_comment_future;
-        std::future<bool> load_image_future;
+        std::future<std::string> load_image_future;
+        bool downloading_image = false;
         sf::Texture captcha_texture;
         sf::Sprite captcha_sprite;
         std::mutex captcha_image_mutex;
 
         auto attached_image_texture = std::make_unique<sf::Texture>();
         sf::Sprite attached_image_sprite;
-        std::mutex attachment_load_mutex;
 
         GoogleCaptchaChallengeInfo challenge_info;
         sf::Text challenge_description_text("", *font, 24);
@@ -2726,6 +2726,8 @@ namespace QuickMedia {
 
         // TODO: Show a white image with "Loading..." text while the captcha image is downloading
 
+        // TODO: Make google captcha images load texture in the main thread, otherwise high cpu usage. I guess its fine right now because of only 1 image?
+
         // TODO: Make this work with other sites than 4chan
         auto request_google_captcha_image = [this, &captcha_texture, &captcha_image_mutex, &navigation_stage, &captcha_sprite, &challenge_description_text](GoogleCaptchaChallengeInfo &challenge_info) {
             std::string payload_image_data;
@@ -2865,26 +2867,21 @@ namespace QuickMedia {
                                 content_url = std::move(prev_content_url);
                                 redraw = true;
                             } else {
+                                if(downloading_image && load_image_future.valid())
+                                    load_image_future.get();
+                                downloading_image = true;
                                 navigation_stage = NavigationStage::VIEWING_ATTACHED_IMAGE;
-                                load_image_future = std::async(std::launch::async, [this, &image_board, &attached_image_texture, &attached_image_sprite, &attachment_load_mutex]() -> bool {
+                                load_image_future = std::async(std::launch::async, [this, &image_board]() {
+                                    std::string image_data;
                                     BodyItem *selected_item = body->get_selected();
                                     if(!selected_item || selected_item->attached_content_url.empty()) {
-                                        return false;
+                                        return image_data;
                                     }
-                                    std::string image_data;
-                                    if(download_to_string(selected_item->attached_content_url, image_data, {}, image_board->use_tor) != DownloadResult::OK) {
+                                    if(download_to_string_cache(selected_item->attached_content_url, image_data, {}, image_board->use_tor) != DownloadResult::OK) {
                                         show_notification(image_board->name, "Failed to download image: " + selected_item->attached_content_url, Urgency::CRITICAL);
-                                        return false;
-                                    }
-
-                                    std::lock_guard<std::mutex> lock(attachment_load_mutex);
-                                    if(!attached_image_texture->loadFromMemory(image_data.data(), image_data.size())) {
-                                        show_notification(image_board->name, "Failed to load image downloaded from url: " + selected_item->attached_content_url, Urgency::CRITICAL);
-                                        return false;
+                                        image_data.clear();
                                     }
-                                    attached_image_texture->setSmooth(true);
-                                    attached_image_sprite.setTexture(*attached_image_texture, true);
-                                    return true;
+                                    return image_data;
                                 });
                             }
                         }
@@ -3050,8 +3047,24 @@ namespace QuickMedia {
             } else if(navigation_stage == NavigationStage::POSTING_COMMENT) {
                 // TODO: Show "Posting..." when posting comment
             } else if(navigation_stage == NavigationStage::VIEWING_ATTACHED_IMAGE) {
+                std::string image_data;
+                if(downloading_image && load_image_future.valid() && load_image_future.wait_for(std::chrono::seconds(0)) == std::future_status::ready) {
+                    downloading_image = false;
+                    image_data = load_image_future.get();
+                    
+                    if(attached_image_texture->loadFromMemory(image_data.data(), image_data.size())) {
+                        attached_image_texture->setSmooth(true);
+                        attached_image_sprite.setTexture(*attached_image_texture, true);
+                    } else {
+                        BodyItem *selected_item = body->get_selected();
+                        std::string selected_item_attached_url;
+                        if(selected_item)
+                            selected_item_attached_url = selected_item->attached_content_url;
+                        show_notification(image_board->name, "Failed to load image downloaded from url: " + selected_item->attached_content_url, Urgency::CRITICAL);
+                    }
+                }
+                
                 // TODO: Show a white image with the text "Downloading..." while the image is downloading and loading
-                std::lock_guard<std::mutex> lock(attachment_load_mutex);
                 if(attached_image_texture->getNativeHandle() != 0) {
                     auto content_size = window_size;
                     sf::Vector2u texture_size = attached_image_texture->getSize();
-- 
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