imagelist: Use thread-safe queue for thumbnail queue

Moved thread-safe queue into it's own header so it can be used in both
the imagelist and imagefetcher.

src/booru/imagefetcher.h

@@ -1,49 +1,17 @@
 #ifndef _IMAGEFETCHER_H_
 #define _IMAGEFETCHER_H_
 
-#include "curler.h"
-
-#include <mutex>
-#include <queue>
 #include <thread>
 
+#include "curler.h"
+#include "tsqueue.h"
+
 namespace AhoViewer
 {
     namespace Booru
     {
         class ImageFetcher : public sigc::trackable
         {
-            // Thread-safe queue {{{
-            template <typename T>
-            class Queue
-            {
-            public:
-                bool push(T value)
-                {
-                    std::unique_lock<std::mutex> lock(m_Mutex);
-                    m_Queue.push(value);
-                    return true;
-                }
-                bool pop(T & v)
-                {
-                    std::unique_lock<std::mutex> lock(m_Mutex);
-                    if (m_Queue.empty())
-                        return false;
-                    v = m_Queue.front();
-                    m_Queue.pop();
-                    return true;
-                }
-                void clear()
-                {
-                    std::unique_lock<std::mutex> lock(m_Mutex);
-                    while (!m_Queue.empty()) m_Queue.pop();
-                }
-
-            private:
-                std::queue<T> m_Queue;
-                std::mutex m_Mutex;
-            };
-            // }}}
         public:
             ImageFetcher();
             virtual ~ImageFetcher();
@@ -79,7 +47,7 @@ namespace AhoViewer
 
             CURLM *m_MultiHandle;
             int m_RunningHandles;
-            Queue<Curler*> m_CurlerQueue;
+            TSQueue<Curler*> m_CurlerQueue;
             std::vector<Curler*> m_Curlers;
 
             std::weak_ptr<Glib::Dispatcher> m_SignalHandleAdded;

src/imagelist.cc

@@ -216,10 +216,7 @@ void ImageList::load_thumbnails()
                 return;
 
             const Glib::RefPtr<Gdk::Pixbuf> thumb = m_Images[i]->get_thumbnail();
-            {
-                std::lock_guard<std::mutex> lock(m_ThumbnailMutex);
-                m_ThumbnailQueue.push(PixbufPair(i, std::move(thumb)));
-            }
+            m_ThumbnailQueue.push(PixbufPair(i, std::move(thumb)));
 
             if (!m_ThumbnailCancel->is_cancelled())
                 m_SignalThumbnailLoaded();
@@ -256,8 +253,7 @@ void ImageList::cancel_thumbnail_thread()
     if (m_ThumbnailThread.joinable())
         m_ThumbnailThread.join();
 
-    std::lock_guard<std::mutex> lock(m_ThumbnailMutex);
-    m_ThumbnailQueue = std::queue<PixbufPair>();
+    m_ThumbnailQueue.clear();
 }
 
 // Returns an unsorted vector of the paths to valid T's.
@@ -287,18 +283,10 @@ std::vector<std::string> ImageList::get_entries(const std::string &path)
 void ImageList::on_thumbnail_loaded()
 {
     m_ThumbnailLoadedConn.block();
+    PixbufPair p;
 
-    while (!m_ThumbnailCancel->is_cancelled() && !m_ThumbnailQueue.empty())
-    {
-        std::unique_lock<std::mutex> lock(m_ThumbnailMutex);
-        PixbufPair p = m_ThumbnailQueue.front();
-        lock.unlock();
+    while (!m_ThumbnailCancel->is_cancelled() && m_ThumbnailQueue.pop(p))
         m_Widget->set_pixbuf(p.first, p.second);
-        lock.lock();
-        // Queue may have been clared during set_pixbuf
-        if (!m_ThumbnailQueue.empty())
-            m_ThumbnailQueue.pop();
-    }
 
     m_ThumbnailLoadedConn.unblock();
 }

src/imagelist.h

@@ -3,14 +3,14 @@
 
 #include <gtkmm.h>
 #include <memory>
-#include <queue>
 #include <string>
 #include <vector>
 
 #include "archive/archive.h"
 #include "booru/xml.h"
 #include "image.h"
 #include "threadpool.h"
+#include "tsqueue.h"
 
 namespace AhoViewer
 {
@@ -27,7 +27,7 @@ namespace AhoViewer
         using SignalArchiveErrorType = sigc::signal<void, const std::string>;
 
         // Used for async thumbnail pixbuf loading
-        using PixbufPair = std::pair<size_t, const Glib::RefPtr<Gdk::Pixbuf>>;
+        using PixbufPair = std::pair<size_t, Glib::RefPtr<Gdk::Pixbuf>>;
     public:
         // ImageList::Widget {{{
         // This is used by ThumbnailBar and Booru::Page.
@@ -154,7 +154,7 @@ namespace AhoViewer
         std::vector<size_t> m_Cache;
         std::unique_ptr<Archive> m_Archive;
         std::vector<std::string> m_ArchiveEntries;
-        std::queue<PixbufPair> m_ThumbnailQueue;
+        TSQueue<PixbufPair> m_ThumbnailQueue;
         std::function<int(size_t, size_t)> m_IndexSort;
 
         Glib::RefPtr<Gio::Cancellable> m_CacheCancel;

src/tsqueue.h

@@ -0,0 +1,40 @@
+#ifndef _TSQUEUE_H_
+#define _TSQUEUE_H_
+
+#include <mutex>
+#include <queue>
+
+namespace AhoViewer
+{
+    template <typename T>
+    class TSQueue
+    {
+    public:
+        bool push(T v)
+        {
+            std::unique_lock<std::mutex> lock(m_Mutex);
+            m_Queue.push(v);
+            return true;
+        }
+        bool pop(T &v)
+        {
+            std::unique_lock<std::mutex> lock(m_Mutex);
+            if (m_Queue.empty())
+                return false;
+            v = m_Queue.front();
+            m_Queue.pop();
+            return true;
+        }
+        void clear()
+        {
+            std::unique_lock<std::mutex> lock(m_Mutex);
+            while (!m_Queue.empty()) m_Queue.pop();
+        }
+
+    private:
+        std::queue<T> m_Queue;
+        std::mutex m_Mutex;
+    };
+}
+
+#endif /* _TSQUEUE_H_ */