Text scanner refactor (#517)

* Fix return type

* Pass search function as a constructor argument

* Pass constructor as a details object

For consistency with other complex constructors and improved semantics.

* Convert _ignorePoints to a single optional function

* Organize functions

* Rename ignorePoints to ignorePoint

3 files changed, 117 insertions, 120 deletions

diff --git a/ext/bg/js/search-query-parser.js b/ext/bg/js/search-query-parser.js
index caace34b..e1e37d1c 100644
--- a/ext/bg/js/search-query-parser.js
+++ b/ext/bg/js/search-query-parser.js
@@ -34,12 +34,12 @@ class QueryParser {
         this._queryParser = document.querySelector('#query-parser-content');
         this._queryParserSelect = document.querySelector('#query-parser-select-container');
         this._queryParserGenerator = new QueryParserGenerator();
-        this._textScanner = new TextScanner(
-            this._queryParser,
-            () => [],
-            []
-        );
-        this._textScanner.onSearchSource = this._onSearchSource.bind(this);
+        this._textScanner = new TextScanner({
+            node: this._queryParser,
+            ignoreElements: () => [],
+            ignorePoint: null,
+            search: this._search.bind(this)
+        });
     }
 
     async prepare() {
@@ -74,11 +74,11 @@ class QueryParser {
         this._textScanner.searchAt(e.clientX, e.clientY, 'click');
     }
 
-    async _onSearchSource(textSource, cause) {
+    async _search(textSource, cause) {
         if (textSource === null) { return null; }
 
         const searchText = this._textScanner.getTextSourceContent(textSource, this._options.scanning.length);
-        if (searchText.length === 0) { return; }
+        if (searchText.length === 0) { return null; }
 
         const {definitions, length} = await apiTermsFind(searchText, {}, this._getOptionsContext());
         if (definitions.length === 0) { return null; }
diff --git a/ext/fg/js/frontend.js b/ext/fg/js/frontend.js
index 9de6597e..78440991 100644
--- a/ext/fg/js/frontend.js
+++ b/ext/fg/js/frontend.js
@@ -39,12 +39,12 @@ class Frontend {
         this._enabledEventListeners = new EventListenerCollection();
         this._activeModifiers = new Set();
         this._optionsUpdatePending = false;
-        this._textScanner = new TextScanner(
-            window,
-            () => this._popup.isProxy() ? [] : [this._popup.getContainer()],
-            [(x, y) => this._popup.containsPoint(x, y)]
-        );
-        this._textScanner.onSearchSource = this._onSearchSource.bind(this);
+        this._textScanner = new TextScanner({
+            node: window,
+            ignoreElements: () => this._popup.isProxy() ? [] : [this._popup.getContainer()],
+            ignorePoint: (x, y) => this._popup.containsPoint(x, y),
+            search: this._search.bind(this)
+        });
 
         this._windowMessageHandlers = new Map([
             ['popupClose', () => this._textScanner.clearSelection(false)],
@@ -107,7 +107,7 @@ class Frontend {
     }
 
     async setTextSource(textSource) {
-        await this._onSearchSource(textSource, 'script');
+        await this._search(textSource, 'script');
         this._textScanner.setCurrentTextSource(textSource);
     }
 
@@ -137,7 +137,7 @@ class Frontend {
         const textSourceCurrent = this._textScanner.getCurrentTextSource();
         const causeCurrent = this._textScanner.causeCurrent;
         if (textSourceCurrent !== null && causeCurrent !== null) {
-            await this._onSearchSource(textSourceCurrent, causeCurrent);
+            await this._search(textSourceCurrent, causeCurrent);
         }
     }
 
@@ -204,7 +204,7 @@ class Frontend {
         await this.updateOptions();
     }
 
-    async _onSearchSource(textSource, cause) {
+    async _search(textSource, cause) {
         await this._updatePendingOptions();
 
         let results = null;
diff --git a/ext/mixed/js/text-scanner.js b/ext/mixed/js/text-scanner.js
index 2ed6c3b9..b8688b08 100644
--- a/ext/mixed/js/text-scanner.js
+++ b/ext/mixed/js/text-scanner.js
@@ -22,11 +22,12 @@
  */
 
 class TextScanner extends EventDispatcher {
-    constructor(node, ignoreElements, ignorePoints) {
+    constructor({node, ignoreElements, ignorePoint, search}) {
         super();
         this._node = node;
         this._ignoreElements = ignoreElements;
-        this._ignorePoints = ignorePoints;
+        this._ignorePoint = ignorePoint;
+        this._search = search;
 
         this._ignoreNodes = null;
 
@@ -69,6 +70,103 @@ class TextScanner extends EventDispatcher {
         return this._causeCurrent;
     }
 
+    setEnabled(enabled) {
+        this._eventListeners.removeAllEventListeners();
+        this._enabled = enabled;
+        if (this._enabled) {
+            this._hookEvents();
+        } else {
+            this.clearSelection(true);
+        }
+    }
+
+    setOptions(options) {
+        this._options = options;
+    }
+
+    async searchAt(x, y, cause) {
+        try {
+            this._scanTimerClear();
+
+            if (this._pendingLookup) {
+                return;
+            }
+
+            if (typeof this._ignorePoint === 'function' && await this._ignorePoint(x, y)) {
+                return;
+            }
+
+            const textSource = docRangeFromPoint(x, y, this._options.scanning.deepDomScan);
+            try {
+                if (this._textSourceCurrent !== null && this._textSourceCurrent.equals(textSource)) {
+                    return;
+                }
+
+                this._pendingLookup = true;
+                const result = await this._search(textSource, cause);
+                if (result !== null) {
+                    this._causeCurrent = cause;
+                    this.setCurrentTextSource(textSource);
+                }
+                this._pendingLookup = false;
+            } finally {
+                if (textSource !== null) {
+                    textSource.cleanup();
+                }
+            }
+        } catch (e) {
+            yomichan.logError(e);
+        }
+    }
+
+    getTextSourceContent(textSource, length) {
+        const clonedTextSource = textSource.clone();
+
+        clonedTextSource.setEndOffset(length);
+
+        if (this._ignoreNodes !== null && clonedTextSource.range) {
+            length = clonedTextSource.text().length;
+            while (clonedTextSource.range && length > 0) {
+                const nodes = TextSourceRange.getNodesInRange(clonedTextSource.range);
+                if (!TextSourceRange.anyNodeMatchesSelector(nodes, this._ignoreNodes)) {
+                    break;
+                }
+                --length;
+                clonedTextSource.setEndOffset(length);
+            }
+        }
+
+        return clonedTextSource.text();
+    }
+
+    clearSelection(passive) {
+        if (!this._canClearSelection) { return; }
+        if (this._textSourceCurrent !== null) {
+            if (this._textSourceCurrentSelected) {
+                this._textSourceCurrent.deselect();
+            }
+            this._textSourceCurrent = null;
+            this._textSourceCurrentSelected = false;
+        }
+        this.trigger('clearSelection', {passive});
+    }
+
+    getCurrentTextSource() {
+        return this._textSourceCurrent;
+    }
+
+    setCurrentTextSource(textSource) {
+        this._textSourceCurrent = textSource;
+        if (this._options.scanning.selectText) {
+            this._textSourceCurrent.select();
+            this._textSourceCurrentSelected = true;
+        } else {
+            this._textSourceCurrentSelected = false;
+        }
+    }
+
+    // Private
+
     _onMouseOver(e) {
         if (this._ignoreElements().includes(e.target)) {
             this._scanTimerClear();
@@ -221,10 +319,6 @@ class TextScanner extends EventDispatcher {
         e.preventDefault(); // Disable scroll
     }
 
-    async onSearchSource(_textSource, _cause) {
-        throw new Error('Override me');
-    }
-
     async _scanTimerWait() {
         const delay = this._options.scanning.delay;
         const promise = promiseTimeout(delay, true);
@@ -245,16 +339,6 @@ class TextScanner extends EventDispatcher {
         }
     }
 
-    setEnabled(enabled) {
-        this._eventListeners.removeAllEventListeners();
-        this._enabled = enabled;
-        if (this._enabled) {
-            this._hookEvents();
-        } else {
-            this.clearSelection(true);
-        }
-    }
-
     _hookEvents() {
         const eventListenerInfos = this._getMouseEventListeners();
         if (this._options.scanning.touchInputEnabled) {
@@ -287,93 +371,6 @@ class TextScanner extends EventDispatcher {
         ];
     }
 
-    setOptions(options) {
-        this._options = options;
-    }
-
-    async searchAt(x, y, cause) {
-        try {
-            this._scanTimerClear();
-
-            if (this._pendingLookup) {
-                return;
-            }
-
-            for (const ignorePointFn of this._ignorePoints) {
-                if (await ignorePointFn(x, y)) {
-                    return;
-                }
-            }
-
-            const textSource = docRangeFromPoint(x, y, this._options.scanning.deepDomScan);
-            try {
-                if (this._textSourceCurrent !== null && this._textSourceCurrent.equals(textSource)) {
-                    return;
-                }
-
-                this._pendingLookup = true;
-                const result = await this.onSearchSource(textSource, cause);
-                if (result !== null) {
-                    this._causeCurrent = cause;
-                    this.setCurrentTextSource(textSource);
-                }
-                this._pendingLookup = false;
-            } finally {
-                if (textSource !== null) {
-                    textSource.cleanup();
-                }
-            }
-        } catch (e) {
-            yomichan.logError(e);
-        }
-    }
-
-    getTextSourceContent(textSource, length) {
-        const clonedTextSource = textSource.clone();
-
-        clonedTextSource.setEndOffset(length);
-
-        if (this._ignoreNodes !== null && clonedTextSource.range) {
-            length = clonedTextSource.text().length;
-            while (clonedTextSource.range && length > 0) {
-                const nodes = TextSourceRange.getNodesInRange(clonedTextSource.range);
-                if (!TextSourceRange.anyNodeMatchesSelector(nodes, this._ignoreNodes)) {
-                    break;
-                }
-                --length;
-                clonedTextSource.setEndOffset(length);
-            }
-        }
-
-        return clonedTextSource.text();
-    }
-
-    clearSelection(passive) {
-        if (!this._canClearSelection) { return; }
-        if (this._textSourceCurrent !== null) {
-            if (this._textSourceCurrentSelected) {
-                this._textSourceCurrent.deselect();
-            }
-            this._textSourceCurrent = null;
-            this._textSourceCurrentSelected = false;
-        }
-        this.trigger('clearSelection', {passive});
-    }
-
-    getCurrentTextSource() {
-        return this._textSourceCurrent;
-    }
-
-    setCurrentTextSource(textSource) {
-        this._textSourceCurrent = textSource;
-        if (this._options.scanning.selectText) {
-            this._textSourceCurrent.select();
-            this._textSourceCurrentSelected = true;
-        } else {
-            this._textSourceCurrentSelected = false;
-        }
-    }
-
     _isScanningModifierPressed(scanningModifier, mouseEvent) {
         switch (scanningModifier) {
             case 'alt': return mouseEvent.altKey;