fix(imageCache): improve cache management & file handling

quickshell/Common/CacheUtils.qml

@@ -7,17 +7,62 @@ import qs.Common
 Singleton {
     id: root
 
+    // Filenames present on disk, so CachingImage never points an Image at a
+    // missing cache file (Qt logs that as a "Cannot open" warning).
+    property var cachedFiles: ({})
+
+    Component.onCompleted: scan()
+
+    function scan() {
+        Proc.runCommand("imagecache_scan", ["ls", "-1", Paths.stringify(Paths.imagecache)], function (output, exitCode) {
+            const map = {};
+            if (exitCode === 0 && output) {
+                const lines = output.split("\n");
+                for (var i = 0; i < lines.length; i++) {
+                    const name = lines[i].trim();
+                    if (name)
+                        map[name] = true;
+                }
+            }
+            root.cachedFiles = map;
+        });
+    }
+
+    function hasCachedFile(name) {
+        return name ? root.cachedFiles[name] === true : false;
+    }
+
+    function recordCachedFile(name) {
+        if (name)
+            root.cachedFiles[name] = true;
+    }
+
+    function forgetCachedFile(name) {
+        if (name && root.cachedFiles[name] !== undefined)
+            delete root.cachedFiles[name];
+    }
+
     function clearImageCache() {
         Quickshell.execDetached(["rm", "-rf", Paths.stringify(Paths.imagecache)]);
         Paths.mkdir(Paths.imagecache);
+        root.cachedFiles = ({});
     }
 
     function clearOldCache(ageInMinutes) {
-        Quickshell.execDetached(["find", Paths.stringify(Paths.imagecache), "-name", "*.png", "-mmin", `+${ageInMinutes}`, "-delete"]);
+        // Rescan on delete completion since we can't know which files matched.
+        Proc.runCommand("imagecache_prune", ["find", Paths.stringify(Paths.imagecache), "-name", "*.png", "-mmin", `+${ageInMinutes}`, "-delete"], function (output, exitCode) {
+            root.scan();
+        });
     }
 
     function clearCacheForSize(size) {
         Quickshell.execDetached(["find", Paths.stringify(Paths.imagecache), "-name", `*@${size}x${size}.png`, "-delete"]);
+        const suffix = `@${size}x${size}.png`;
+        const map = {};
+        for (const key in root.cachedFiles)
+            if (!key.endsWith(suffix))
+                map[key] = true;
+        root.cachedFiles = map;
     }
 
     function getCacheSize(callback) {

quickshell/Widgets/CachingImage.qml

@@ -39,7 +39,8 @@ Item {
     }
 
     readonly property string imageHash: normalizedPath ? djb2Hash(normalizedPath) : ""
-    readonly property string cachePath: imageHash && !isRemoteUrl && !isAnimated ? `${Paths.stringify(Paths.imagecache)}/${imageHash}@${maxCacheSize}x${maxCacheSize}.png` : ""
+    readonly property string cacheFileName: imageHash && !isRemoteUrl && !isAnimated ? `${imageHash}@${maxCacheSize}x${maxCacheSize}.png` : ""
+    readonly property string cachePath: cacheFileName ? `${Paths.stringify(Paths.imagecache)}/${cacheFileName}` : ""
     readonly property string encodedImagePath: {
         if (!normalizedPath)
             return "";
@@ -74,6 +75,7 @@ Item {
                 if (!root._fromCache)
                     return;
                 root._fromCache = false;
+                CacheUtils.forgetCachedFile(root.cacheFileName);
                 source = root.encodedImagePath;
                 return;
             case Image.Ready:
@@ -83,7 +85,11 @@ Item {
                     return;
                 Paths.mkdir(Paths.imagecache);
                 const grabPath = root.cachePath;
-                grabToImage(res => res.saveToFile(grabPath));
+                const grabName = root.cacheFileName;
+                grabToImage(res => {
+                    if (res.saveToFile(grabPath))
+                        CacheUtils.recordCachedFile(grabName);
+                });
                 return;
             }
         }
@@ -108,7 +114,13 @@ Item {
             return;
         }
         Paths.mkdir(Paths.imagecache);
-        _fromCache = true;
+        // Read cache only when present; else load source and cache it on Ready
-        staticImg.source = cachePath;
+        if (CacheUtils.hasCachedFile(cacheFileName)) {
+            _fromCache = true;
+            staticImg.source = cachePath;
+        } else {
+            _fromCache = false;
+            staticImg.source = encodedImagePath;
+        }
     }
 }