feat: move resource pack images to QPixmapCache

This takes care of evicting entries when the cache gets too big for us,
so we can add new entries without much worries.

Signed-off-by: flow <flowlnlnln@gmail.com>

launcher/minecraft/mod/ResourcePack.cpp

@@ -6,6 +6,8 @@
 
 #include "Version.h"
 
+#include "minecraft/mod/tasks/LocalResourcePackParseTask.h"
+
 // Values taken from:
 // https://minecraft.fandom.com/wiki/Tutorials/Creating_a_resource_pack#Formatting_pack.mcmeta
 static const QMap<int, std::pair<Version, Version>> s_pack_format_versions = {
@@ -41,7 +43,29 @@ void ResourcePack::setImage(QImage new_image)
 
     Q_ASSERT(!new_image.isNull());
 
-    m_pack_image = new_image;
+    if (m_pack_image_cache_key.key.isValid())
+        QPixmapCache::remove(m_pack_image_cache_key.key);
+
+    m_pack_image_cache_key.key = QPixmapCache::insert(QPixmap::fromImage(new_image));
+    m_pack_image_cache_key.was_ever_used = true;
+}
+
+QPixmap ResourcePack::image(QSize size)
+{
+    QPixmap cached_image;
+    if (QPixmapCache::find(m_pack_image_cache_key.key, &cached_image)) {
+        if (size.isNull())
+            return cached_image;
+        return cached_image.scaled(size);
+    }
+
+    // No valid image we can get
+    if (!m_pack_image_cache_key.was_ever_used)
+        return {};
+
+    // Imaged got evicted from the cache. Re-process it and retry.
+    ResourcePackUtils::process(*this);
+    return image(size);
 }
 
 std::pair<Version, Version> ResourcePack::compatibleVersions() const

launcher/minecraft/mod/ResourcePack.h

@@ -5,6 +5,7 @@
 #include <QImage>
 #include <QMutex>
 #include <QPixmap>
+#include <QPixmapCache>
 
 class Version;
 
@@ -30,8 +31,7 @@ class ResourcePack : public Resource {
     [[nodiscard]] QString description() const { return m_description; }
 
     /** Gets the image of the resource pack, converted to a QPixmap for drawing, and scaled to size. */
-    [[nodiscard]] QPixmap image(QSize size) const { return QPixmap::fromImage(m_pack_image).scaled(size); }
-    [[nodiscard]] QSize image_size() const { return m_pack_image.size(); }
+    [[nodiscard]] QPixmap image(QSize size);
 
     /** Thread-safe. */
     void setPackFormat(int new_format_id);
@@ -57,8 +57,13 @@ class ResourcePack : public Resource {
      */
     QString m_description;
 
-    /** The resource pack's image, as per the pack.png file.
-     *  TODO: This could probably be just a key into a static image cache.
+    /** The resource pack's image file cache key, for access in the QPixmapCache global instance.
+     *
+     *  The 'was_ever_used' state simply identifies whether the key was never inserted on the cache (true),
+     *  so as to tell whether a cache entry is inexistent or if it was just evicted from the cache.
      */
-    QImage m_pack_image;
+    struct {
+        QPixmapCache::Key key;
+        bool was_ever_used = false;
+    } m_pack_image_cache_key;
 };

launcher/minecraft/mod/tasks/LocalResourcePackParseTask.cpp

@@ -24,6 +24,8 @@
 #include <quazip/quazip.h>
 #include <quazip/quazipfile.h>
 
+#include <QCryptographicHash>
+
 namespace ResourcePackUtils {
 
 bool process(ResourcePack& pack)

launcher/ui/widgets/InfoFrame.cpp

@@ -105,7 +105,7 @@ static const QMap<QChar, QString> s_value_to_color = {
     {'f', "#FFFFFF"}
 };
 
-void InfoFrame::updateWithResourcePack(const ResourcePack& resource_pack)
+void InfoFrame::updateWithResourcePack(ResourcePack& resource_pack)
 {
     setName(resource_pack.name());
 

launcher/ui/widgets/InfoFrame.h

@@ -40,7 +40,7 @@ class InfoFrame : public QFrame {
 
     void updateWithMod(Mod const& m);
     void updateWithResource(Resource const& resource);
-    void updateWithResourcePack(ResourcePack const& rp);
+    void updateWithResourcePack(ResourcePack& rp);
 
    public slots:
     void descriptionEllipsisHandler(QString link);