perf: reduce main-thread work in the extension

- Clear the thumbnail cache asynchronously in batches instead of a
  synchronous enumerate + delete on the compositor thread
- Prune the thumbnail path cache on item delete and clear-all
- Compute the image/url/color row flags once per row instead of
  recomputing isUrl/isColor several times
- Lower-case the excluded-app list once instead of on every read

strata@edu4rdshl.dev/extension.js

@@ -59,10 +59,10 @@ export default class StrataExtension extends Extension {
         this._daemonRestartAttempts = 0;
 
         this._settings = this.getSettings();
-        this._excludedApps = this._settings.get_strv('excluded-apps');
+        this._excludedApps = this._readExcluded();
         this._readSizeLimits();
         this._settings.connectObject(
-            'changed::excluded-apps', () => { this._excludedApps = this._settings.get_strv('excluded-apps'); },
+            'changed::excluded-apps', () => { this._excludedApps = this._readExcluded(); },
             'changed::max-history',   () => { this._readSizeLimits(); this._pushConfig(); },
             'changed::max-text-mb',   () => { this._readSizeLimits(); this._pushConfig(); },
             'changed::max-image-mb',  () => { this._readSizeLimits(); this._pushConfig(); },
@@ -392,23 +392,50 @@ export default class StrataExtension extends Extension {
 
         this._historyClearedId = this._proxy.connectSignal('HistoryCleared',
             () => {
-                try {
-                    const dir = `${GLib.get_user_cache_dir()}/strata/thumbnails`;
-                    const d = Gio.File.new_for_path(dir);
-                    if (d.query_exists(null)) {
-                        const en = d.enumerate_children(
-                            'standard::name', Gio.FileQueryInfoFlags.NONE, null);
-                        let info;
-                        while ((info = en.next_file(null))) {
-                            try { d.get_child(info.get_name()).delete(null); } catch { /* best-effort cleanup */ }
-                        }
-                        en.close(null);
-                    }
-                } catch (e) { logError('cache clear failed', e); }
+                this._clearThumbnailCache();
                 this._addIdleSource(() => this._panel?.clearItems());
             });
     }
 
+    /** Delete every cached thumbnail without blocking the compositor:
+     *  enumerate and unlink asynchronously in batches. */
+    _clearThumbnailCache() {
+        const dir = Gio.File.new_for_path(
+            `${GLib.get_user_cache_dir()}/strata/thumbnails`);
+        dir.enumerate_children_async(
+            'standard::name', Gio.FileQueryInfoFlags.NONE,
+            GLib.PRIORITY_DEFAULT, null,
+            (d, res) => {
+                let en;
+                try {
+                    en = d.enumerate_children_finish(res);
+                } catch {
+                    return; // dir missing or unreadable
+                }
+                const step = () => {
+                    en.next_files_async(32, GLib.PRIORITY_DEFAULT, null, (e, r) => {
+                        let infos;
+                        try {
+                            infos = e.next_files_finish(r);
+                        } catch {
+                            infos = [];
+                        }
+                        if (infos.length === 0) {
+                            e.close_async(GLib.PRIORITY_DEFAULT, null, () => {});
+                            return;
+                        }
+                        for (const info of infos) {
+                            e.get_child(info).delete_async(
+                                GLib.PRIORITY_DEFAULT, null,
+                                (f, rr) => { try { f.delete_finish(rr); } catch { /* best-effort */ } });
+                        }
+                        step();
+                    });
+                };
+                step();
+            });
+    }
+
     _disconnectSignals() {
         if (this._itemAddedId && this._proxy) {
             this._proxy.disconnectSignal(this._itemAddedId);
@@ -459,9 +486,13 @@ export default class StrataExtension extends Extension {
         });
     }
 
+    _readExcluded() {
+        return this._settings.get_strv('excluded-apps').map(s => s.toLowerCase());
+    }
+
     _isExcluded(appClass) {
         if (!appClass) return false;
-        return this._excludedApps.some(ex => appClass.includes(ex.toLowerCase()));
+        return this._excludedApps.some(ex => appClass.includes(ex));
     }
 
 

strata@edu4rdshl.dev/ui/clipboardItem.js

@@ -57,8 +57,11 @@ export const ClipboardItem = GObject.registerClass({
             x_expand: true,
         });
 
-        row.add_child(this._buildLeading(mimeType, preview));
-        row.add_child(this._buildContent(mimeType, preview));
+        const isImage = mimeType.startsWith('image/');
+        const urlLike = !isImage && isUrl(preview ?? '');
+        const colorLike = !isImage && !urlLike && isColor(preview ?? '');
+        row.add_child(this._buildLeading(mimeType, preview, isImage, colorLike));
+        row.add_child(this._buildContent(preview, isImage, urlLike, colorLike));
 
         const deleteBtn = new St.Button({
             style_class: 'strata-item-delete',
@@ -88,11 +91,11 @@ export const ClipboardItem = GObject.registerClass({
         });
     }
 
-    _buildLeading(mimeType, preview) {
-        if (mimeType.startsWith('image/')) {
+    _buildLeading(mimeType, preview, isImage, colorLike) {
+        if (isImage) {
             return this._buildThumbnail(this._id);
         }
-        if (isColor(preview)) {
+        if (colorLike) {
             return this._buildColorSwatch(preview);
         }
         const icon = new St.Icon({
@@ -197,7 +200,7 @@ export const ClipboardItem = GObject.registerClass({
         });
     }
 
-    _buildContent(mimeType, preview) {
+    _buildContent(preview, isImage, urlLike, colorLike) {
         preview = preview ?? '';
         const box = new St.BoxLayout({
             vertical: true,
@@ -208,17 +211,17 @@ export const ClipboardItem = GObject.registerClass({
         let mainText;
         let subText = '';
 
-        if (mimeType.startsWith('image/')) {
+        if (isImage) {
             // Generic label - the thumbnail identifies the image, and the
             // on-clipboard format (often PNG even for a copied GIF/WebP) is an
             // implementation detail that misleads more than it informs.
             mainText = 'Image';
-        } else if (isUrl(preview)) {
+        } else if (urlLike) {
             mainText = preview.trim();
             try {
                 subText = GLib.Uri.parse(preview.trim(), GLib.UriFlags.NONE).get_host() ?? '';
             } catch { /* not a parseable URI */ }
-        } else if (isColor(preview)) {
+        } else if (colorLike) {
             mainText = preview.trim().toUpperCase();
             subText  = 'Color';
         } else {
@@ -230,7 +233,7 @@ export const ClipboardItem = GObject.registerClass({
 
         const labelMain = new St.Label({
             text: mainText || '(empty)',
-            style_class: `strata-item-text${isUrl(preview) ? ' strata-item-url' : ''}`,
+            style_class: `strata-item-text${urlLike ? ' strata-item-url' : ''}`,
             x_expand: true,
             y_align: Clutter.ActorAlign.CENTER,
         });

strata@edu4rdshl.dev/ui/panel.js

@@ -278,6 +278,7 @@ export class StrataPanel {
 
     removeItem(id) {
         this._items = this._items.filter(i => i.id !== id);
+        this._thumbCache.delete(id);
         // Keep the search snapshot in sync so a deleted/pruned item sitting in
         // the not-yet-rendered tail can't be re-created as a phantom row when
         // scrolling appends the next page. Adjust _searchRendered if the removed
@@ -310,6 +311,7 @@ export class StrataPanel {
         this._hoveredWidget = null;
         this._activeWidget  = null;
         this._widgets.clear();
+        this._thumbCache.clear();
         this._itemList.destroy_all_children();
     }