From 9dcc9665ceac7dc08ff3ba95b647d2d1a01e92d3 Mon Sep 17 00:00:00 2001
From: Alex Ling <hkalexling@gmail.com>
Date: Sat, 12 Dec 2020 16:15:16 +0000
Subject: [PATCH] Cancel a download job when deleted from web UI

---
 src/mangadex/downloader.cr | 11 +++++++++++
 src/plugin/downloader.cr   |  8 ++++++++
 src/queue.cr               | 15 +++++++++++++++
 3 files changed, 34 insertions(+)

diff --git a/src/mangadex/downloader.cr b/src/mangadex/downloader.cr
index ff395d9..e2babb6 100644
--- a/src/mangadex/downloader.cr
+++ b/src/mangadex/downloader.cr
@@ -91,6 +91,7 @@ module MangaDex
           end
 
           channel.send page_job
+          break unless @queue.exists? job
         end
       end
 
@@ -98,6 +99,9 @@ module MangaDex
         page_jobs = [] of PageJob
         chapter.pages.size.times do
           page_job = channel.receive
+
+          break unless @queue.exists? job
+
           Logger.debug "[#{page_job.success ? "success" : "failed"}] " \
                        "#{page_job.url}"
           page_jobs << page_job
@@ -110,6 +114,13 @@ module MangaDex
             Logger.error msg
           end
         end
+
+        unless @queue.exists? job
+          Logger.debug "Download cancelled"
+          @downloading = false
+          next
+        end
+
         fail_count = page_jobs.count { |j| !j.success }
         Logger.debug "Download completed. " \
                      "#{fail_count}/#{page_jobs.size} failed"
diff --git a/src/plugin/downloader.cr b/src/plugin/downloader.cr
index 99cd52d..054698e 100644
--- a/src/plugin/downloader.cr
+++ b/src/plugin/downloader.cr
@@ -66,6 +66,8 @@ class Plugin
       fail_count = 0
 
       while page = plugin.next_page
+        break unless @queue.exists? job
+
         fn = process_filename page["filename"].as_s
         url = page["url"].as_s
         headers = HTTP::Headers.new
@@ -109,6 +111,12 @@ class Plugin
         end
       end
 
+      unless @queue.exists? job
+        Logger.debug "Download cancelled"
+        @downloading = false
+        return
+      end
+
       Logger.debug "Download completed. #{fail_count}/#{pages} failed"
       writer.close
       filename = File.join File.dirname(zip_path), File.basename(zip_path,
diff --git a/src/queue.cr b/src/queue.cr
index 0281b61..c9f805c 100644
--- a/src/queue.cr
+++ b/src/queue.cr
@@ -196,6 +196,21 @@ class Queue
     self.delete job.id
   end
 
+  def exists?(id : String)
+    res = false
+    MainFiber.run do
+      DB.open "sqlite3://#{@path}" do |db|
+        res = db.query_one "select count(*) from queue where id = (?)", id,
+          as: Bool
+      end
+    end
+    res
+  end
+
+  def exists?(job : Job)
+    self.exists? job.id
+  end
+
   def delete_status(status : JobStatus)
     MainFiber.run do
       DB.open "sqlite3://#{@path}" do |db|