10 files changed, 764 insertions, 71 deletions

diff --git a/ext/mixed/js/api.js b/ext/mixed/js/api.js
new file mode 100644
index 00000000..8ed1d996
--- /dev/null
+++ b/ext/mixed/js/api.js
@@ -0,0 +1,130 @@
+/*
+ * Copyright (C) 2016-2020  Alex Yatskov <alex@foosoft.net>
+ * Author: Alex Yatskov <alex@foosoft.net>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+
+function apiOptionsSchemaGet() {
+    return _apiInvoke('optionsSchemaGet');
+}
+
+function apiOptionsGet(optionsContext) {
+    return _apiInvoke('optionsGet', {optionsContext});
+}
+
+function apiOptionsGetFull() {
+    return _apiInvoke('optionsGetFull');
+}
+
+function apiOptionsSet(changedOptions, optionsContext, source) {
+    return _apiInvoke('optionsSet', {changedOptions, optionsContext, source});
+}
+
+function apiOptionsSave(source) {
+    return _apiInvoke('optionsSave', {source});
+}
+
+function apiTermsFind(text, details, optionsContext) {
+    return _apiInvoke('termsFind', {text, details, optionsContext});
+}
+
+function apiTextParse(text, optionsContext) {
+    return _apiInvoke('textParse', {text, optionsContext});
+}
+
+function apiTextParseMecab(text, optionsContext) {
+    return _apiInvoke('textParseMecab', {text, optionsContext});
+}
+
+function apiKanjiFind(text, optionsContext) {
+    return _apiInvoke('kanjiFind', {text, optionsContext});
+}
+
+function apiDefinitionAdd(definition, mode, context, optionsContext) {
+    return _apiInvoke('definitionAdd', {definition, mode, context, optionsContext});
+}
+
+function apiDefinitionsAddable(definitions, modes, optionsContext) {
+    return _apiInvoke('definitionsAddable', {definitions, modes, optionsContext}).catch(() => null);
+}
+
+function apiNoteView(noteId) {
+    return _apiInvoke('noteView', {noteId});
+}
+
+function apiTemplateRender(template, data, dynamic) {
+    return _apiInvoke('templateRender', {data, template, dynamic});
+}
+
+function apiAudioGetUrl(definition, source, optionsContext) {
+    return _apiInvoke('audioGetUrl', {definition, source, optionsContext});
+}
+
+function apiCommandExec(command, params) {
+    return _apiInvoke('commandExec', {command, params});
+}
+
+function apiScreenshotGet(options) {
+    return _apiInvoke('screenshotGet', {options});
+}
+
+function apiForward(action, params) {
+    return _apiInvoke('forward', {action, params});
+}
+
+function apiFrameInformationGet() {
+    return _apiInvoke('frameInformationGet');
+}
+
+function apiInjectStylesheet(css) {
+    return _apiInvoke('injectStylesheet', {css});
+}
+
+function apiGetEnvironmentInfo() {
+    return _apiInvoke('getEnvironmentInfo');
+}
+
+function apiClipboardGet() {
+    return _apiInvoke('clipboardGet');
+}
+
+function _apiInvoke(action, params={}) {
+    const data = {action, params};
+    return new Promise((resolve, reject) => {
+        try {
+            chrome.runtime.sendMessage(data, (response) => {
+                _apiCheckLastError(chrome.runtime.lastError);
+                if (response !== null && typeof response === 'object') {
+                    if (typeof response.error !== 'undefined') {
+                        reject(jsonToError(response.error));
+                    } else {
+                        resolve(response.result);
+                    }
+                } else {
+                    const message = response === null ? 'Unexpected null response' : `Unexpected response of type ${typeof response}`;
+                    reject(new Error(`${message} (${JSON.stringify(data)})`));
+                }
+            });
+        } catch (e) {
+            reject(e);
+            yomichan.triggerOrphaned(e);
+        }
+    });
+}
+
+function _apiCheckLastError() {
+    // NOP
+}
diff --git a/ext/mixed/js/audio.js b/ext/mixed/js/audio.js
index 35f283a4..b0c5fa82 100644
--- a/ext/mixed/js/audio.js
+++ b/ext/mixed/js/audio.js
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2019  Alex Yatskov <alex@foosoft.net>
+ * Copyright (C) 2019-2020  Alex Yatskov <alex@foosoft.net>
  * Author: Alex Yatskov <alex@foosoft.net>
  *
  * This program is free software: you can redistribute it and/or modify
@@ -13,7 +13,7 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
 
diff --git a/ext/mixed/js/core.js b/ext/mixed/js/core.js
index b5911535..54e8a9d2 100644
--- a/ext/mixed/js/core.js
+++ b/ext/mixed/js/core.js
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2019  Alex Yatskov <alex@foosoft.net>
+ * Copyright (C) 2019-2020  Alex Yatskov <alex@foosoft.net>
  * Author: Alex Yatskov <alex@foosoft.net>
  *
  * This program is free software: you can redistribute it and/or modify
@@ -13,7 +13,7 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
 
@@ -118,6 +118,10 @@ function toIterable(value) {
     throw new Error('Could not convert to iterable');
 }
 
+function stringReverse(string) {
+    return string.split('').reverse().join('').replace(/([\uDC00-\uDFFF])([\uD800-\uDBFF])/g, '$2$1');
+}
+
 
 /*
  * Async utilities
@@ -175,3 +179,96 @@ function stringReplaceAsync(str, regex, replacer) {
     parts.push(str.substring(index));
     return Promise.all(parts).then((v) => v.join(''));
 }
+
+
+/*
+ * Common events
+ */
+
+class EventDispatcher {
+    constructor() {
+        this._eventMap = new Map();
+    }
+
+    trigger(eventName, details) {
+        const callbacks = this._eventMap.get(eventName);
+        if (typeof callbacks === 'undefined') { return false; }
+
+        for (const callback of callbacks) {
+            callback(details);
+        }
+    }
+
+    on(eventName, callback) {
+        let callbacks = this._eventMap.get(eventName);
+        if (typeof callbacks === 'undefined') {
+            callbacks = [];
+            this._eventMap.set(eventName, callbacks);
+        }
+        callbacks.push(callback);
+    }
+
+    off(eventName, callback) {
+        const callbacks = this._eventMap.get(eventName);
+        if (typeof callbacks === 'undefined') { return true; }
+
+        const ii = callbacks.length;
+        for (let i = 0; i < ii; ++i) {
+            if (callbacks[i] === callback) {
+                callbacks.splice(i, 1);
+                if (callbacks.length === 0) {
+                    this._eventMap.delete(eventName);
+                }
+                return true;
+            }
+        }
+        return false;
+    }
+}
+
+
+/*
+ * Default message handlers
+ */
+
+const yomichan = (() => {
+    class Yomichan extends EventDispatcher {
+        constructor() {
+            super();
+
+            this._messageHandlers = new Map([
+                ['getUrl', this._onMessageGetUrl.bind(this)],
+                ['optionsUpdate', this._onMessageOptionsUpdate.bind(this)]
+            ]);
+
+            chrome.runtime.onMessage.addListener(this._onMessage.bind(this));
+        }
+
+        // Public
+
+        triggerOrphaned(error) {
+            this.trigger('orphaned', {error});
+        }
+
+        // Private
+
+        _onMessage({action, params}, sender, callback) {
+            const handler = this._messageHandlers.get(action);
+            if (typeof handler !== 'function') { return false; }
+
+            const result = handler(params, sender);
+            callback(result);
+            return false;
+        }
+
+        _onMessageGetUrl() {
+            return {url: window.location.href};
+        }
+
+        _onMessageOptionsUpdate({source}) {
+            this.trigger('optionsUpdate', {source});
+        }
+    }
+
+    return new Yomichan();
+})();
diff --git a/ext/mixed/js/display-context.js b/ext/mixed/js/display-context.js
index 4b399881..c11c2342 100644
--- a/ext/mixed/js/display-context.js
+++ b/ext/mixed/js/display-context.js
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2019  Alex Yatskov <alex@foosoft.net>
+ * Copyright (C) 2019-2020  Alex Yatskov <alex@foosoft.net>
  * Author: Alex Yatskov <alex@foosoft.net>
  *
  * This program is free software: you can redistribute it and/or modify
@@ -13,7 +13,7 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
 
diff --git a/ext/mixed/js/display.js b/ext/mixed/js/display.js
index 7d5e4e7d..e756f948 100644
--- a/ext/mixed/js/display.js
+++ b/ext/mixed/js/display.js
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2017  Alex Yatskov <alex@foosoft.net>
+ * Copyright (C) 2017-2020  Alex Yatskov <alex@foosoft.net>
  * Author: Alex Yatskov <alex@foosoft.net>
  *
  * This program is free software: you can redistribute it and/or modify
@@ -13,7 +13,7 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
 
@@ -144,7 +144,7 @@ class Display {
         try {
             e.preventDefault();
 
-            const textSource = docRangeFromPoint(e.clientX, e.clientY, this.options);
+            const textSource = docRangeFromPoint(e.clientX, e.clientY, this.options.scanning.deepDomScan);
             if (textSource === null) {
                 return false;
             }
@@ -193,9 +193,8 @@ class Display {
 
     onKeyDown(e) {
         const key = Display.getKeyFromEvent(e);
-        const handlers = Display.onKeyDownHandlers;
-        if (hasOwn(handlers, key)) {
-            const handler = handlers[key];
+        const handler = Display._onKeyDownHandlers.get(key);
+        if (typeof handler === 'function') {
             if (handler(this, e)) {
                 e.preventDefault();
                 return true;
@@ -211,23 +210,18 @@ class Display {
                 e.preventDefault();
             }
         } else if (e.shiftKey) {
-            const delta = -e.deltaX || e.deltaY;
-            if (delta > 0) {
-                this.sourceTermView();
-                e.preventDefault();
-            } else if (delta < 0) {
-                this.nextTermView();
-                e.preventDefault();
-            }
+            this.onHistoryWheel(e);
         }
     }
 
-    onRuntimeMessage({action, params}, sender, callback) {
-        const handlers = Display.runtimeMessageHandlers;
-        if (hasOwn(handlers, action)) {
-            const handler = handlers[action];
-            const result = handler(this, params);
-            callback(result);
+    onHistoryWheel(e) {
+        const delta = -e.deltaX || e.deltaY;
+        if (delta > 0) {
+            this.sourceTermView();
+            e.preventDefault();
+        } else if (delta < 0) {
+            this.nextTermView();
+            e.preventDefault();
         }
     }
 
@@ -241,7 +235,7 @@ class Display {
 
     async initialize(options=null) {
         await this.updateOptions(options);
-        chrome.runtime.onMessage.addListener(this.onRuntimeMessage.bind(this));
+        yomichan.on('optionsUpdate', () => this.updateOptions(null));
     }
 
     async updateOptions(options) {
@@ -301,6 +295,7 @@ class Display {
             this.addEventListeners('.kanji-link', 'click', this.onKanjiLookup.bind(this));
             this.addEventListeners('.source-term', 'click', this.onSourceTermView.bind(this));
             this.addEventListeners('.next-term', 'click', this.onNextTermView.bind(this));
+            this.addEventListeners('.term-navigation', 'wheel', this.onHistoryWheel.bind(this), {passive: false});
             if (this.options.scanning.enablePopupSearch) {
                 this.addEventListeners('.glossary-item', 'mouseup', this.onGlossaryMouseUp.bind(this));
                 this.addEventListeners('.glossary-item', 'mousedown', this.onGlossaryMouseDown.bind(this));
@@ -761,101 +756,101 @@ class Display {
     }
 }
 
-Display.onKeyDownHandlers = {
-    'Escape': (self) => {
+Display._onKeyDownHandlers = new Map([
+    ['Escape', (self) => {
         self.onSearchClear();
         return true;
-    },
+    }],
 
-    'PageUp': (self, e) => {
+    ['PageUp', (self, e) => {
         if (e.altKey) {
             self.entryScrollIntoView(self.index - 3, null, true);
             return true;
         }
         return false;
-    },
+    }],
 
-    'PageDown': (self, e) => {
+    ['PageDown', (self, e) => {
         if (e.altKey) {
             self.entryScrollIntoView(self.index + 3, null, true);
             return true;
         }
         return false;
-    },
+    }],
 
-    'End': (self, e) => {
+    ['End', (self, e) => {
         if (e.altKey) {
             self.entryScrollIntoView(self.definitions.length - 1, null, true);
             return true;
         }
         return false;
-    },
+    }],
 
-    'Home': (self, e) => {
+    ['Home', (self, e) => {
         if (e.altKey) {
             self.entryScrollIntoView(0, null, true);
             return true;
         }
         return false;
-    },
+    }],
 
-    'ArrowUp': (self, e) => {
+    ['ArrowUp', (self, e) => {
         if (e.altKey) {
             self.entryScrollIntoView(self.index - 1, null, true);
             return true;
         }
         return false;
-    },
+    }],
 
-    'ArrowDown': (self, e) => {
+    ['ArrowDown', (self, e) => {
         if (e.altKey) {
             self.entryScrollIntoView(self.index + 1, null, true);
             return true;
         }
         return false;
-    },
+    }],
 
-    'B': (self, e) => {
+    ['B', (self, e) => {
         if (e.altKey) {
             self.sourceTermView();
             return true;
         }
         return false;
-    },
+    }],
 
-    'F': (self, e) => {
+    ['F', (self, e) => {
         if (e.altKey) {
             self.nextTermView();
             return true;
         }
         return false;
-    },
+    }],
 
-    'E': (self, e) => {
+    ['E', (self, e) => {
         if (e.altKey) {
             self.noteTryAdd('term-kanji');
             return true;
         }
         return false;
-    },
+    }],
 
-    'K': (self, e) => {
+    ['K', (self, e) => {
         if (e.altKey) {
             self.noteTryAdd('kanji');
             return true;
         }
         return false;
-    },
+    }],
 
-    'R': (self, e) => {
+    ['R', (self, e) => {
         if (e.altKey) {
             self.noteTryAdd('term-kana');
             return true;
         }
         return false;
-    },
+    }],
 
-    'P': (self, e) => {
+    ['P', (self, e) => {
         if (e.altKey) {
             const entry = self.getEntry(self.index);
             if (entry !== null && entry.dataset.type === 'term') {
@@ -864,17 +859,13 @@ Display.onKeyDownHandlers = {
             return true;
         }
         return false;
-    },
+    }],
 
-    'V': (self, e) => {
+    ['V', (self, e) => {
         if (e.altKey) {
             self.noteTryView();
             return true;
         }
         return false;
-    }
-};
-
-Display.runtimeMessageHandlers = {
-    optionsUpdate: (self) => self.updateOptions(null)
-};
+    }]
+]);
diff --git a/ext/mixed/js/dom.js b/ext/mixed/js/dom.js
index 4e4d49e3..807a48e1 100644
--- a/ext/mixed/js/dom.js
+++ b/ext/mixed/js/dom.js
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2019  Alex Yatskov <alex@foosoft.net>
+ * Copyright (C) 2019-2020  Alex Yatskov <alex@foosoft.net>
  * Author: Alex Yatskov <alex@foosoft.net>
  *
  * This program is free software: you can redistribute it and/or modify
@@ -13,7 +13,7 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
 
diff --git a/ext/mixed/js/japanese.js b/ext/mixed/js/japanese.js
index 8b841b2e..23b2bd36 100644
--- a/ext/mixed/js/japanese.js
+++ b/ext/mixed/js/japanese.js
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2016  Alex Yatskov <alex@foosoft.net>
+ * Copyright (C) 2016-2020  Alex Yatskov <alex@foosoft.net>
  * Author: Alex Yatskov <alex@foosoft.net>
  *
  * This program is free software: you can redistribute it and/or modify
@@ -13,7 +13,7 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
 
@@ -160,16 +160,17 @@ function jpDistributeFuriganaInflected(expression, reading, source) {
     }
     const offset = source.length - stemLength;
 
-    const stemExpression = source.slice(0, source.length - offset);
-    const stemReading = reading.slice(
-        0, offset === 0 ? reading.length : reading.length - expression.length + stemLength
+    const stemExpression = source.substring(0, source.length - offset);
+    const stemReading = reading.substring(
+        0,
+        offset === 0 ? reading.length : reading.length - expression.length + stemLength
     );
     for (const segment of jpDistributeFurigana(stemExpression, stemReading)) {
         output.push(segment);
     }
 
     if (stemLength !== source.length) {
-        output.push({text: source.slice(stemLength)});
+        output.push({text: source.substring(stemLength)});
     }
 
     return output;
diff --git a/ext/mixed/js/scroll.js b/ext/mixed/js/scroll.js
index 824fd92b..5829d294 100644
--- a/ext/mixed/js/scroll.js
+++ b/ext/mixed/js/scroll.js
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2019  Alex Yatskov <alex@foosoft.net>
+ * Copyright (C) 2019-2020  Alex Yatskov <alex@foosoft.net>
  * Author: Alex Yatskov <alex@foosoft.net>
  *
  * This program is free software: you can redistribute it and/or modify
@@ -13,7 +13,7 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
 
diff --git a/ext/mixed/js/text-scanner.js b/ext/mixed/js/text-scanner.js
new file mode 100644
index 00000000..a05dd2ee
--- /dev/null
+++ b/ext/mixed/js/text-scanner.js
@@ -0,0 +1,378 @@
+/*
+ * Copyright (C) 2019-2020  Alex Yatskov <alex@foosoft.net>
+ * Author: Alex Yatskov <alex@foosoft.net>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+
+class TextScanner {
+    constructor(node, ignoreNodes, ignoreElements, ignorePoints) {
+        this.node = node;
+        this.ignoreNodes = (Array.isArray(ignoreNodes) && ignoreNodes.length > 0 ? ignoreNodes.join(',') : null);
+        this.ignoreElements = ignoreElements;
+        this.ignorePoints = ignorePoints;
+
+        this.scanTimerPromise = null;
+        this.textSourceCurrent = null;
+        this.pendingLookup = false;
+        this.options = null;
+
+        this.enabled = false;
+        this.eventListeners = [];
+
+        this.primaryTouchIdentifier = null;
+        this.preventNextContextMenu = false;
+        this.preventNextMouseDown = false;
+        this.preventNextClick = false;
+        this.preventScroll = false;
+    }
+
+    onMouseOver(e) {
+        if (this.ignoreElements.includes(e.target)) {
+            this.scanTimerClear();
+        }
+    }
+
+    onMouseMove(e) {
+        this.scanTimerClear();
+
+        if (this.pendingLookup || DOM.isMouseButtonDown(e, 'primary')) {
+            return;
+        }
+
+        const scanningOptions = this.options.scanning;
+        const scanningModifier = scanningOptions.modifier;
+        if (!(
+            TextScanner.isScanningModifierPressed(scanningModifier, e) ||
+            (scanningOptions.middleMouse && DOM.isMouseButtonDown(e, 'auxiliary'))
+        )) {
+            return;
+        }
+
+        const search = async () => {
+            if (scanningModifier === 'none') {
+                if (!await this.scanTimerWait()) {
+                    // Aborted
+                    return;
+                }
+            }
+
+            await this.searchAt(e.clientX, e.clientY, 'mouse');
+        };
+
+        search();
+    }
+
+    onMouseDown(e) {
+        if (this.preventNextMouseDown) {
+            this.preventNextMouseDown = false;
+            this.preventNextClick = true;
+            e.preventDefault();
+            e.stopPropagation();
+            return false;
+        }
+
+        if (DOM.isMouseButtonDown(e, 'primary')) {
+            this.scanTimerClear();
+            this.onSearchClear(true);
+        }
+    }
+
+    onMouseOut() {
+        this.scanTimerClear();
+    }
+
+    onClick(e) {
+        if (this.preventNextClick) {
+            this.preventNextClick = false;
+            e.preventDefault();
+            e.stopPropagation();
+            return false;
+        }
+    }
+
+    onAuxClick() {
+        this.preventNextContextMenu = false;
+    }
+
+    onContextMenu(e) {
+        if (this.preventNextContextMenu) {
+            this.preventNextContextMenu = false;
+            e.preventDefault();
+            e.stopPropagation();
+            return false;
+        }
+    }
+
+    onTouchStart(e) {
+        if (this.primaryTouchIdentifier !== null || e.changedTouches.length === 0) {
+            return;
+        }
+
+        this.preventScroll = false;
+        this.preventNextContextMenu = false;
+        this.preventNextMouseDown = false;
+        this.preventNextClick = false;
+
+        const primaryTouch = e.changedTouches[0];
+        if (DOM.isPointInSelection(primaryTouch.clientX, primaryTouch.clientY, this.node.getSelection())) {
+            return;
+        }
+
+        this.primaryTouchIdentifier = primaryTouch.identifier;
+
+        if (this.pendingLookup) {
+            return;
+        }
+
+        const textSourceCurrentPrevious = this.textSourceCurrent !== null ? this.textSourceCurrent.clone() : null;
+
+        this.searchAt(primaryTouch.clientX, primaryTouch.clientY, 'touchStart')
+        .then(() => {
+            if (
+                this.textSourceCurrent === null ||
+                this.textSourceCurrent.equals(textSourceCurrentPrevious)
+            ) {
+                return;
+            }
+
+            this.preventScroll = true;
+            this.preventNextContextMenu = true;
+            this.preventNextMouseDown = true;
+        });
+    }
+
+    onTouchEnd(e) {
+        if (
+            this.primaryTouchIdentifier === null ||
+            TextScanner.getIndexOfTouch(e.changedTouches, this.primaryTouchIdentifier) < 0
+        ) {
+            return;
+        }
+
+        this.primaryTouchIdentifier = null;
+        this.preventScroll = false;
+        this.preventNextClick = false;
+        // Don't revert context menu and mouse down prevention,
+        // since these events can occur after the touch has ended.
+        // this.preventNextContextMenu = false;
+        // this.preventNextMouseDown = false;
+    }
+
+    onTouchCancel(e) {
+        this.onTouchEnd(e);
+    }
+
+    onTouchMove(e) {
+        if (!this.preventScroll || !e.cancelable || this.primaryTouchIdentifier === null) {
+            return;
+        }
+
+        const touches = e.changedTouches;
+        const index = TextScanner.getIndexOfTouch(touches, this.primaryTouchIdentifier);
+        if (index < 0) {
+            return;
+        }
+
+        const primaryTouch = touches[index];
+        this.searchAt(primaryTouch.clientX, primaryTouch.clientY, 'touchMove');
+
+        e.preventDefault(); // Disable scroll
+    }
+
+    async onSearchSource(_textSource, _cause) {
+        throw new Error('Override me');
+    }
+
+    onError(error) {
+        logError(error, false);
+    }
+
+    async scanTimerWait() {
+        const delay = this.options.scanning.delay;
+        const promise = promiseTimeout(delay, true);
+        this.scanTimerPromise = promise;
+        try {
+            return await promise;
+        } finally {
+            if (this.scanTimerPromise === promise) {
+                this.scanTimerPromise = null;
+            }
+        }
+    }
+
+    scanTimerClear() {
+        if (this.scanTimerPromise !== null) {
+            this.scanTimerPromise.resolve(false);
+            this.scanTimerPromise = null;
+        }
+    }
+
+    setEnabled(enabled) {
+        if (enabled) {
+            if (!this.enabled) {
+                this.hookEvents();
+                this.enabled = true;
+            }
+        } else {
+            if (this.enabled) {
+                this.clearEventListeners();
+                this.enabled = false;
+            }
+            this.onSearchClear(false);
+        }
+    }
+
+    hookEvents() {
+        let eventListeners = this.getMouseEventListeners();
+        if (this.options.scanning.touchInputEnabled) {
+            eventListeners = eventListeners.concat(this.getTouchEventListeners());
+        }
+
+        for (const [node, type, listener, options] of eventListeners) {
+            this.addEventListener(node, type, listener, options);
+        }
+    }
+
+    getMouseEventListeners() {
+        return [
+            [this.node, 'mousedown', this.onMouseDown.bind(this)],
+            [this.node, 'mousemove', this.onMouseMove.bind(this)],
+            [this.node, 'mouseover', this.onMouseOver.bind(this)],
+            [this.node, 'mouseout', this.onMouseOut.bind(this)]
+        ];
+    }
+
+    getTouchEventListeners() {
+        return [
+            [this.node, 'click', this.onClick.bind(this)],
+            [this.node, 'auxclick', this.onAuxClick.bind(this)],
+            [this.node, 'touchstart', this.onTouchStart.bind(this)],
+            [this.node, 'touchend', this.onTouchEnd.bind(this)],
+            [this.node, 'touchcancel', this.onTouchCancel.bind(this)],
+            [this.node, 'touchmove', this.onTouchMove.bind(this), {passive: false}],
+            [this.node, 'contextmenu', this.onContextMenu.bind(this)]
+        ];
+    }
+
+    addEventListener(node, type, listener, options) {
+        node.addEventListener(type, listener, options);
+        this.eventListeners.push([node, type, listener, options]);
+    }
+
+    clearEventListeners() {
+        for (const [node, type, listener, options] of this.eventListeners) {
+            node.removeEventListener(type, listener, options);
+        }
+        this.eventListeners = [];
+    }
+
+    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);
+            if (this.textSourceCurrent !== null && this.textSourceCurrent.equals(textSource)) {
+                return;
+            }
+
+            try {
+                this.pendingLookup = true;
+                const result = await this.onSearchSource(textSource, cause);
+                if (result !== null) {
+                    this.textSourceCurrent = textSource;
+                    if (this.options.scanning.selectText) {
+                        textSource.select();
+                    }
+                }
+                this.pendingLookup = false;
+            } finally {
+                if (textSource !== null) {
+                    textSource.cleanup();
+                }
+            }
+        } catch (e) {
+            this.onError(e);
+        }
+    }
+
+    setTextSourceScanLength(textSource, length) {
+        textSource.setEndOffset(length);
+        if (this.ignoreNodes === null || !textSource.range) {
+            return;
+        }
+
+        length = textSource.text().length;
+        while (textSource.range && length > 0) {
+            const nodes = TextSourceRange.getNodesInRange(textSource.range);
+            if (!TextSourceRange.anyNodeMatchesSelector(nodes, this.ignoreNodes)) {
+                break;
+            }
+            --length;
+            textSource.setEndOffset(length);
+        }
+    }
+
+    onSearchClear(_) {
+        if (this.textSourceCurrent !== null) {
+            if (this.options.scanning.selectText) {
+                this.textSourceCurrent.deselect();
+            }
+            this.textSourceCurrent = null;
+        }
+    }
+
+    getCurrentTextSource() {
+        return this.textSourceCurrent;
+    }
+
+    setCurrentTextSource(textSource) {
+        return this.textSourceCurrent = textSource;
+    }
+
+    static isScanningModifierPressed(scanningModifier, mouseEvent) {
+        switch (scanningModifier) {
+            case 'alt': return mouseEvent.altKey;
+            case 'ctrl': return mouseEvent.ctrlKey;
+            case 'shift': return mouseEvent.shiftKey;
+            case 'none': return true;
+            default: return false;
+        }
+    }
+
+    static getIndexOfTouch(touchList, identifier) {
+        for (const i in touchList) {
+            const t = touchList[i];
+            if (t.identifier === identifier) {
+                return i;
+            }
+        }
+        return -1;
+    }
+}
diff --git a/ext/mixed/js/timer.js b/ext/mixed/js/timer.js
new file mode 100644
index 00000000..1caf7a05
--- /dev/null
+++ b/ext/mixed/js/timer.js
@@ -0,0 +1,96 @@
+/*
+ * Copyright (C) 2019-2020  Alex Yatskov <alex@foosoft.net>
+ * Author: Alex Yatskov <alex@foosoft.net>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+
+class Timer {
+    constructor(name) {
+        this.samples = [];
+        this.parent = null;
+
+        this.sample(name);
+        const current = Timer._current;
+        if (current !== null) {
+            current.samples[current.samples.length - 1].children.push(this);
+            this.parent = current;
+        }
+        Timer._current = this;
+    }
+
+    sample(name) {
+        const time = window.performance.now();
+        this.samples.push({
+            name,
+            time,
+            children: []
+        });
+    }
+
+    complete(skip) {
+        this.sample('complete');
+
+        Timer._current = this.parent;
+        if (this.parent === null) {
+            if (!skip) {
+                console.log(this.toString());
+            }
+        } else {
+            if (skip) {
+                const sample = this.parent.samples[this.parent.samples.length - 1];
+                sample.children.splice(sample.children.length - 1, 1);
+            }
+        }
+    }
+
+    duration(sampleIndex) {
+        const sampleIndexIsValid = (typeof sampleIndex === 'number');
+        const startIndex = (sampleIndexIsValid ? sampleIndex : 0);
+        const endIndex = (sampleIndexIsValid ? sampleIndex + 1 : this.times.length - 1);
+        return (this.times[endIndex].time - this.times[startIndex].time);
+    }
+
+    toString() {
+        const indent = '  ';
+        const name = this.samples[0].name;
+        const duration = this.samples[this.samples.length - 1].time - this.samples[0].time;
+        const extensionName = chrome.runtime.getManifest().name;
+        return `${name} took ${duration.toFixed(8)}ms  [${extensionName}]` + Timer._indentString(this.getSampleString(), indent);
+    }
+
+    getSampleString() {
+        const indent = '  ';
+        const duration = this.samples[this.samples.length - 1].time - this.samples[0].time;
+        let message = '';
+
+        for (let i = 0, ii = this.samples.length - 1; i < ii; ++i) {
+            const sample = this.samples[i];
+            const sampleDuration = this.samples[i + 1].time - sample.time;
+            message += `\nSample[${i}] took ${sampleDuration.toFixed(8)}ms (${((sampleDuration / duration) * 100.0).toFixed(1)}%)  [${sample.name}]`;
+            for (const child of sample.children) {
+                message += Timer._indentString(child.getSampleString(), indent);
+            }
+        }
+
+        return message;
+    }
+
+    static _indentString(message, indent) {
+        return message.replace(/\n/g, `\n${indent}`);
+    }
+}
+
+Timer._current = null;