gtk: implement get_attachment_fd and texture/attachment cache, viewport loading

gtk/src/transcript/layouts/image-bubble-layout.vala

@@ -13,30 +13,52 @@ private class SizeCache
         return instance;
     }
 
-    public Graphene.Size? get_size(string image_path) {
-        return size_cache.get(image_path);
+    public Graphene.Size? get_size(string attachment_guid) {
+        return size_cache.get(attachment_guid);
     }
 
-    public void set_size(string image_path, Graphene.Size size) {
-        size_cache.set(image_path, size);
+    public void set_size(string attachment_guid, Graphene.Size size) {
+        size_cache.set(attachment_guid, size);
+    }
+}
+
+private class TextureCache
+{
+    private static TextureCache instance = null;
+    private HashMap<string, Gdk.Texture> texture_cache = new HashMap<string, Gdk.Texture>();
+
+    public static TextureCache get_instance() {
+        if (instance == null) {
+            instance = new TextureCache();
+        }
+        return instance;
+    }
+
+    public Gdk.Texture? get_texture(string attachment_guid) {
+        return texture_cache.get(attachment_guid);
+    }
+
+    public void set_texture(string attachment_guid, Gdk.Texture texture) {
+        texture_cache.set(attachment_guid, texture);
     }
 }
 
 private class ImageBubbleLayout : BubbleLayout
 {
-    public string image_path;
+    public string attachment_guid;
     public bool is_downloaded;
-    public string? attachment_guid;
 
     private Graphene.Size image_size;
     private Gdk.Texture? cached_texture = null;
+    private bool preview_download_queued = false;
 
-    public ImageBubbleLayout(string image_path, bool from_me, Widget parent, float max_width, Graphene.Size? image_size = null) {
+    public ImageBubbleLayout(string attachment_guid, bool from_me, Widget parent, float max_width, Graphene.Size? image_size = null) {
         base(parent, max_width);
         
         this.from_me = from_me;
-        this.image_path = image_path;
+        this.attachment_guid = attachment_guid;
         this.is_downloaded = false;
+        this.cached_texture = TextureCache.get_instance().get_texture(attachment_guid);
 
         // Calculate image dimensions for layout
         calculate_image_dimensions(image_size);
@@ -48,26 +70,25 @@ private class ImageBubbleLayout : BubbleLayout
             return;
         }
 
-        var cached_size = SizeCache.get_instance().get_size(image_path);
+        var cached_size = SizeCache.get_instance().get_size(attachment_guid);
         if (cached_size != null) {
             this.image_size = cached_size;
             return;
         }
 
-        // Try to load the image to get its dimensions
+        this.image_size = Graphene.Size() { width = 200.0f, height = 150.0f };
+    }
+
+    private void queue_preview_download_if_needed() {
+        if (is_downloaded || preview_download_queued || attachment_guid == "") {
+            return;
+        }
+
         try {
-            warning("No image size provided, loading image to get dimensions");
-            
-            var texture = Gdk.Texture.from_filename(image_path);
-            var original_width = (float)texture.get_width();
-            var original_height = (float)texture.get_height();
-            
-            this.image_size = Graphene.Size() { width = original_width, height = original_height };
-            SizeCache.get_instance().set_size(image_path, this.image_size);
-        } catch (Error e) {
-            // Fallback dimensions if image can't be loaded
-            warning("Failed to load image %s: %s", image_path, e.message);
-            this.image_size = Graphene.Size() { width = 200.0f, height = 150.0f };
+            Repository.get_instance().download_attachment(attachment_guid, true);
+            preview_download_queued = true;
+        } catch (GLib.Error e) {
+            warning("Failed to queue preview download for %s: %s", attachment_guid, e.message);
         }
     }
 
@@ -81,9 +102,22 @@ private class ImageBubbleLayout : BubbleLayout
         }
 
         try {
-            cached_texture = Gdk.Texture.from_filename(image_path);
+            int fd = Repository.get_instance().open_attachment_fd(attachment_guid, true);
+            var stream = new UnixInputStream(fd, true);
+            var pixbuf = new Gdk.Pixbuf.from_stream(stream, null);
+            cached_texture = Gdk.Texture.for_pixbuf(pixbuf);
+
+            if (cached_texture != null) {
+                TextureCache.get_instance().set_texture(attachment_guid, cached_texture);
+                this.image_size = Graphene.Size() {
+                    width = (float)cached_texture.get_width(),
+                    height = (float)cached_texture.get_height()
+                };
+                SizeCache.get_instance().set_size(attachment_guid, this.image_size);
+                parent.queue_allocate();
+            }
         } catch (Error e) {
-            warning("Failed to load image %s: %s", image_path, e.message);
+            warning("Failed to load preview image for %s: %s", attachment_guid, e.message);
         }
     }
 
@@ -110,6 +144,7 @@ private class ImageBubbleLayout : BubbleLayout
     }
 
     public override void draw_content(Snapshot snapshot) {
+        queue_preview_download_if_needed();
         load_image_if_needed();
 
         snapshot.save();
@@ -137,4 +172,4 @@ private class ImageBubbleLayout : BubbleLayout
     public override void copy(Gdk.Clipboard clipboard) {
         clipboard.set_texture(cached_texture);
     }
-} 
+}