From a81c33b60aac0752ccca06f5183632146f6c6bf0 Mon Sep 17 00:00:00 2001
From: siikamiika <siikamiika@users.noreply.github.com>
Date: Sat, 18 Apr 2020 22:08:38 +0300
Subject: [PATCH] simplify element source lazy load

---
 ext/fg/js/frame-offset-forwarder.js | 58 ++++++++++++-----------------
 1 file changed, 24 insertions(+), 34 deletions(-)

diff --git a/ext/fg/js/frame-offset-forwarder.js b/ext/fg/js/frame-offset-forwarder.js
index 72731605..f40c642d 100644
--- a/ext/fg/js/frame-offset-forwarder.js
+++ b/ext/fg/js/frame-offset-forwarder.js
@@ -94,52 +94,42 @@ class FrameOffsetForwarder {
     }
 
     _findFrameWithContentWindow(contentWindow) {
-        const elementSources = [
-            () => [...this._frameCache],
-            // will contain duplicates, but frame elements are cheap to handle
-            () => [...document.querySelectorAll('frame, iframe:not(.yomichan-float)')],
-            () => [document.documentElement]
-        ];
-        const getMoreElements = () => {
-            while (true) {
-                const source = elementSources.shift();
-                if (source) {
-                    const elements = source();
-                    if (elements.length === 0) { continue; }
-                    return elements;
-                }
-                return [];
-            }
-        };
-
-        const elements = [];
         const ELEMENT_NODE = Node.ELEMENT_NODE;
-        while (elements.length > 0 || elements.push(...getMoreElements())) {
-            const element = elements.shift();
-            if (element.contentWindow === contentWindow) {
-                this._frameCache.add(element);
-                return element;
-            }
+        for (const elements of this._getFrameElementSources()) {
+            while (elements.length > 0) {
+                const element = elements.shift();
+                if (element.contentWindow === contentWindow) {
+                    this._frameCache.add(element);
+                    return element;
+                }
 
-            const shadowRoot = element.shadowRoot;
-            if (shadowRoot) {
-                for (const child of shadowRoot.children) {
+                const shadowRoot = element.shadowRoot;
+                if (shadowRoot) {
+                    for (const child of shadowRoot.children) {
+                        if (child.nodeType === ELEMENT_NODE) {
+                            elements.push(child);
+                        }
+                    }
+                }
+
+                for (const child of element.children) {
                     if (child.nodeType === ELEMENT_NODE) {
                         elements.push(child);
                     }
                 }
             }
-
-            for (const child of element.children) {
-                if (child.nodeType === ELEMENT_NODE) {
-                    elements.push(child);
-                }
-            }
         }
 
         return null;
     }
 
+    *_getFrameElementSources() {
+        yield [...this._frameCache];
+        // will contain duplicates, but frame elements are cheap to handle
+        yield [...document.querySelectorAll('frame, iframe:not(.yomichan-float)')];
+        yield [document.documentElement];
+    }
+
     _forwardFrameOffsetParent(offset, uniqueId) {
         window.parent.postMessage({action: 'getFrameOffset', params: {offset, uniqueId}}, '*');
     }