Settings binder (#542)

* Fix _modifySetting being async

* Return values for modifySettings's set and splice actions

* Add apiGetSettings

* Create a class which can accumulate tasks to run in bulk

* Create a class which binds input elements to customizable sources

* Create class which binds input elements to settings

* Add support for value transforms

* Remove redundant ObjectPropertyAccessor.getPathArray

* Fix not using correct types for input.min/max/step

* Fix wrong condition

* Use api object

5 files changed, 612 insertions, 34 deletions

diff --git a/ext/bg/js/backend.js b/ext/bg/js/backend.js
index 8df4fd9d..90895737 100644
--- a/ext/bg/js/backend.js
+++ b/ext/bg/js/backend.js
@@ -119,7 +119,8 @@ class Backend {
             ['log',                          {async: false, contentScript: true,  handler: this._onApiLog.bind(this)}],
             ['logIndicatorClear',            {async: false, contentScript: true,  handler: this._onApiLogIndicatorClear.bind(this)}],
             ['createActionPort',             {async: false, contentScript: true,  handler: this._onApiCreateActionPort.bind(this)}],
-            ['modifySettings',               {async: true,  contentScript: true,  handler: this._onApiModifySettings.bind(this)}]
+            ['modifySettings',               {async: true,  contentScript: true,  handler: this._onApiModifySettings.bind(this)}],
+            ['getSettings',                  {async: false, contentScript: true,  handler: this._onApiGetSettings.bind(this)}]
         ]);
         this._messageHandlersWithProgress = new Map([
             ['importDictionaryArchive', {async: true,  contentScript: false, handler: this._onApiImportDictionaryArchive.bind(this)}],
@@ -831,8 +832,8 @@ class Backend {
         const results = [];
         for (const target of targets) {
             try {
-                this._modifySetting(target);
-                results.push({result: true});
+                const result = this._modifySetting(target);
+                results.push({result: utilIsolate(result)});
             } catch (e) {
                 results.push({error: errorToJson(e)});
             }
@@ -841,6 +842,19 @@ class Backend {
         return results;
     }
 
+    _onApiGetSettings({targets}) {
+        const results = [];
+        for (const target of targets) {
+            try {
+                const result = this._getSetting(target);
+                results.push({result: utilIsolate(result)});
+            } catch (e) {
+                results.push({error: errorToJson(e)});
+            }
+        }
+        return results;
+    }
+
     // Command handlers
 
     _createActionListenerPort(port, sender, handlers) {
@@ -1017,45 +1031,53 @@ class Backend {
         }
     }
 
-    async _modifySetting(target) {
+    _getSetting(target) {
+        const options = this._getModifySettingObject(target);
+        const accessor = new ObjectPropertyAccessor(options);
+        const {path} = target;
+        if (typeof path !== 'string') { throw new Error('Invalid path'); }
+        return accessor.get(ObjectPropertyAccessor.getPathArray(path));
+    }
+
+    _modifySetting(target) {
         const options = this._getModifySettingObject(target);
         const accessor = new ObjectPropertyAccessor(options);
         const action = target.action;
         switch (action) {
             case 'set':
-                {
-                    const {path, value} = target;
-                    if (typeof path !== 'string') { throw new Error('Invalid path'); }
-                    accessor.set(ObjectPropertyAccessor.getPathArray(path), value);
-                }
-                break;
+            {
+                const {path, value} = target;
+                if (typeof path !== 'string') { throw new Error('Invalid path'); }
+                const pathArray = ObjectPropertyAccessor.getPathArray(path);
+                accessor.set(pathArray, value);
+                return accessor.get(pathArray);
+            }
             case 'delete':
-                {
-                    const {path} = target;
-                    if (typeof path !== 'string') { throw new Error('Invalid path'); }
-                    accessor.delete(ObjectPropertyAccessor.getPathArray(path));
-                }
-                break;
+            {
+                const {path} = target;
+                if (typeof path !== 'string') { throw new Error('Invalid path'); }
+                accessor.delete(ObjectPropertyAccessor.getPathArray(path));
+                return true;
+            }
             case 'swap':
-                {
-                    const {path1, path2} = target;
-                    if (typeof path1 !== 'string') { throw new Error('Invalid path1'); }
-                    if (typeof path2 !== 'string') { throw new Error('Invalid path2'); }
-                    accessor.swap(ObjectPropertyAccessor.getPathArray(path1), ObjectPropertyAccessor.getPathArray(path2));
-                }
-                break;
+            {
+                const {path1, path2} = target;
+                if (typeof path1 !== 'string') { throw new Error('Invalid path1'); }
+                if (typeof path2 !== 'string') { throw new Error('Invalid path2'); }
+                accessor.swap(ObjectPropertyAccessor.getPathArray(path1), ObjectPropertyAccessor.getPathArray(path2));
+                return true;
+            }
             case 'splice':
-                {
-                    const {path, start, deleteCount, items} = target;
-                    if (typeof path !== 'string') { throw new Error('Invalid path'); }
-                    if (typeof start !== 'number' || Math.floor(start) !== start) { throw new Error('Invalid start'); }
-                    if (typeof deleteCount !== 'number' || Math.floor(deleteCount) !== deleteCount) { throw new Error('Invalid deleteCount'); }
-                    if (!Array.isArray(items)) { throw new Error('Invalid items'); }
-                    const array = accessor.get(ObjectPropertyAccessor.getPathArray(path));
-                    if (!Array.isArray(array)) { throw new Error('Invalid target type'); }
-                    array.splice(start, deleteCount, ...items);
-                }
-                break;
+            {
+                const {path, start, deleteCount, items} = target;
+                if (typeof path !== 'string') { throw new Error('Invalid path'); }
+                if (typeof start !== 'number' || Math.floor(start) !== start) { throw new Error('Invalid start'); }
+                if (typeof deleteCount !== 'number' || Math.floor(deleteCount) !== deleteCount) { throw new Error('Invalid deleteCount'); }
+                if (!Array.isArray(items)) { throw new Error('Invalid items'); }
+                const array = accessor.get(ObjectPropertyAccessor.getPathArray(path));
+                if (!Array.isArray(array)) { throw new Error('Invalid target type'); }
+                return array.splice(start, deleteCount, ...items);
+            }
             default:
                 throw new Error(`Unknown action: ${action}`);
         }
diff --git a/ext/bg/js/settings/dom-settings-binder.js b/ext/bg/js/settings/dom-settings-binder.js
new file mode 100644
index 00000000..0441ec29
--- /dev/null
+++ b/ext/bg/js/settings/dom-settings-binder.js
@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) 2020  Yomichan Authors
+ *
+ * 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/>.
+ */
+
+/* global
+ * DOMDataBinder
+ * api
+ * getOptionsContext
+ */
+
+class DOMSettingsBinder {
+    constructor({getOptionsContext, transforms=null}) {
+        this._getOptionsContext = getOptionsContext;
+        this._defaultScope = 'profile';
+        this._dataBinder = new DOMDataBinder({
+            selector: '[data-setting]',
+            createElementMetadata: this._createElementMetadata.bind(this),
+            compareElementMetadata: this._compareElementMetadata.bind(this),
+            getValues: this._getValues.bind(this),
+            setValues: this._setValues.bind(this)
+        });
+        this._transforms = new Map(transforms !== null ? transforms : []);
+    }
+
+    observe(element) {
+        this._dataBinder.observe(element);
+    }
+
+    disconnect() {
+        this._dataBinder.disconnect();
+    }
+
+    refresh() {
+        this._dataBinder.refresh();
+    }
+
+    // Private
+
+    _createElementMetadata(element) {
+        return {
+            path: element.dataset.setting,
+            scope: element.dataset.scope,
+            transformPre: element.dataset.transformPre,
+            transformPost: element.dataset.transformPost
+        };
+    }
+
+    _compareElementMetadata(metadata1, metadata2) {
+        return (
+            metadata1.path === metadata2.path &&
+            metadata1.scope === metadata2.scope &&
+            metadata1.transformPre === metadata2.transformPre &&
+            metadata1.transformPost === metadata2.transformPost
+        );
+    }
+
+    async _getValues(targets) {
+        const settingsTargets = [];
+        for (const {metadata: {path, scope}} of targets) {
+            const target = {
+                path,
+                scope: scope || this._defaultScope
+            };
+            if (target.scope === 'profile') {
+                target.optionsContext = this._getOptionsContext();
+            }
+            settingsTargets.push(target);
+        }
+        return this._transformResults(await api.getSettings(settingsTargets), targets);
+    }
+
+    async _setValues(targets) {
+        const settingsTargets = [];
+        for (const {metadata, value, element} of targets) {
+            const {path, scope, transformPre} = metadata;
+            const target = {
+                path,
+                scope: scope || this._defaultScope,
+                action: 'set',
+                value: this._transform(value, transformPre, metadata, element)
+            };
+            if (target.scope === 'profile') {
+                target.optionsContext = this._getOptionsContext();
+            }
+            settingsTargets.push(target);
+        }
+        return this._transformResults(await api.modifySettings(settingsTargets), targets);
+    }
+
+    _transform(value, transform, metadata, element) {
+        if (typeof transform === 'string') {
+            const transformFunction = this._transforms.get(transform);
+            if (typeof transformFunction !== 'undefined') {
+                value = transformFunction(value, metadata, element);
+            }
+        }
+        return value;
+    }
+
+    _transformResults(values, targets) {
+        return values.map((value, i) => {
+            const error = value.error;
+            if (error) { return jsonToError(error); }
+            const {metadata, element} = targets[i];
+            const result = this._transform(value.result, metadata.transformPost, metadata, element);
+            return {result};
+        });
+    }
+}
diff --git a/ext/mixed/js/api.js b/ext/mixed/js/api.js
index e09a0db6..2d5ad9e7 100644
--- a/ext/mixed/js/api.js
+++ b/ext/mixed/js/api.js
@@ -172,6 +172,10 @@ const api = (() => {
             return this._invoke('modifySettings', {targets, source});
         }
 
+        getSettings(targets) {
+            return this._invoke('getSettings', {targets});
+        }
+
         // Invoke functions with progress
 
         importDictionaryArchive(archiveContent, details, onProgress) {
diff --git a/ext/mixed/js/dom-data-binder.js b/ext/mixed/js/dom-data-binder.js
new file mode 100644
index 00000000..05a84240
--- /dev/null
+++ b/ext/mixed/js/dom-data-binder.js
@@ -0,0 +1,349 @@
+/*
+ * Copyright (C) 2020  Yomichan Authors
+ *
+ * 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/>.
+ */
+
+/* global
+ * TaskAccumulator
+ */
+
+class DOMDataBinder {
+    constructor({selector, ignoreSelectors=[], createElementMetadata, compareElementMetadata, getValues, setValues, onError=null}) {
+        this._selector = selector;
+        this._ignoreSelectors = ignoreSelectors;
+        this._createElementMetadata = createElementMetadata;
+        this._compareElementMetadata = compareElementMetadata;
+        this._getValues = getValues;
+        this._setValues = setValues;
+        this._onError = onError;
+        this._updateTasks = new TaskAccumulator(this._onBulkUpdate.bind(this));
+        this._assignTasks = new TaskAccumulator(this._onBulkAssign.bind(this));
+        this._mutationObserver = new MutationObserver(this._onMutation.bind(this));
+        this._observingElement = null;
+        this._elementMap = new Map(); // Map([element => observer]...)
+        this._elementAncestorMap = new Map(); // Map([element => Set([observer]...))
+    }
+
+    observe(element) {
+        if (this._isObserving) { return; }
+
+        this._observingElement = element;
+        this._mutationObserver.observe(element, {
+            attributes: true,
+            attributeOldValue: true,
+            childList: true,
+            subtree: true
+        });
+        this._onMutation([{
+            type: 'childList',
+            target: element.parentNode,
+            addedNodes: [element],
+            removedNodes: []
+        }]);
+    }
+
+    disconnect() {
+        if (!this._isObserving) { return; }
+
+        this._mutationObserver.disconnect();
+        this._observingElement = null;
+
+        for (const observer of this._elementMap.values()) {
+            this._removeObserver(observer);
+        }
+    }
+
+    async refresh() {
+        await this._updateTasks.enqueue(null, {all: true});
+    }
+
+    // Private
+
+    _onMutation(mutationList) {
+        for (const mutation of mutationList) {
+            switch (mutation.type) {
+                case 'childList':
+                    this._onChildListMutation(mutation);
+                    break;
+                case 'attributes':
+                    this._onAttributeMutation(mutation);
+                    break;
+            }
+        }
+    }
+
+    _onChildListMutation({addedNodes, removedNodes, target}) {
+        const selector = this._selector;
+        const ELEMENT_NODE = Node.ELEMENT_NODE;
+
+        for (const node of removedNodes) {
+            const observers = this._elementAncestorMap.get(node);
+            if (typeof observers === 'undefined') { continue; }
+            for (const observer of observers) {
+                this._removeObserver(observer);
+            }
+        }
+
+        for (const node of addedNodes) {
+            if (node.nodeType !== ELEMENT_NODE) { continue; }
+            if (node.matches(selector)) {
+                this._createObserver(node);
+            }
+            for (const childNode of node.querySelectorAll(selector)) {
+                this._createObserver(childNode);
+            }
+        }
+
+        if (addedNodes.length !== 0 || addedNodes.length !== 0) {
+            const observer = this._elementMap.get(target);
+            if (typeof observer !== 'undefined') {
+                observer.updateValue();
+            }
+        }
+    }
+
+    _onAttributeMutation({target}) {
+        const selector = this._selector;
+        const observers = this._elementAncestorMap.get(target);
+        if (typeof observers !== 'undefined') {
+            for (const observer of observers) {
+                const element = observer.element;
+                if (
+                    !element.matches(selector) ||
+                    this._shouldIgnoreElement(element) ||
+                    this._isObserverStale(observer)
+                ) {
+                    this._removeObserver(observer);
+                }
+            }
+        }
+
+        if (target.matches(selector)) {
+            this._createObserver(target);
+        }
+    }
+
+    async _onBulkUpdate(tasks) {
+        let all = false;
+        const targets = [];
+        for (const [observer, task] of tasks) {
+            if (observer === null) {
+                if (task.data.all) {
+                    all = true;
+                    break;
+                }
+            } else {
+                targets.push([observer, task]);
+            }
+        }
+        if (all) {
+            targets.length = 0;
+            for (const observer of this._elementMap.values()) {
+                targets.push([observer, null]);
+            }
+        }
+
+        const args = targets.map(([observer]) => ({
+            element: observer.element,
+            metadata: observer.metadata
+        }));
+        const responses = await this._getValues(args);
+        this._applyValues(targets, responses, true);
+    }
+
+    async _onBulkAssign(tasks) {
+        const targets = tasks;
+        const args = targets.map(([observer, task]) => ({
+            element: observer.element,
+            metadata: observer.metadata,
+            value: task.data.value
+        }));
+        const responses = await this._setValues(args);
+        this._applyValues(targets, responses, false);
+    }
+
+    _onElementChange(observer) {
+        const value = this._getElementValue(observer.element);
+        observer.value = value;
+        observer.hasValue = true;
+        this._assignTasks.enqueue(observer, {value});
+    }
+
+    _applyValues(targets, response, ignoreStale) {
+        if (!Array.isArray(response)) { return; }
+
+        for (let i = 0, ii = targets.length; i < ii; ++i) {
+            const [observer, task] = targets[i];
+            const {error, result} = response[i];
+            const stale = (task !== null && task.stale);
+
+            if (error) {
+                if (typeof this._onError === 'function') {
+                    this._onError(error, stale, observer.element, observer.metadata);
+                }
+                continue;
+            }
+
+            if (stale && !ignoreStale) { continue; }
+
+            observer.value = result;
+            observer.hasValue = true;
+            this._setElementValue(observer.element, result);
+        }
+    }
+
+    _createObserver(element) {
+        if (this._elementMap.has(element) || this._shouldIgnoreElement(element)) { return; }
+
+        const metadata = this._createElementMetadata(element);
+        const nodeName = element.nodeName.toUpperCase();
+        const ancestors = this._getAncestors(element);
+        const observer = {
+            element,
+            ancestors,
+            type: (nodeName === 'INPUT' ? element.type : null),
+            value: null,
+            hasValue: false,
+            onChange: null,
+            metadata
+        };
+        observer.onChange = this._onElementChange.bind(this, observer);
+        this._elementMap.set(element, observer);
+
+        element.addEventListener('change', observer.onChange, false);
+
+        for (const ancestor of ancestors) {
+            let observers = this._elementAncestorMap.get(ancestor);
+            if (typeof observers === 'undefined') {
+                observers = new Set();
+                this._elementAncestorMap.set(ancestor, observers);
+            }
+            observers.add(observer);
+        }
+
+        this._updateTasks.enqueue(observer);
+    }
+
+    _removeObserver(observer) {
+        const {element, ancestors} = observer;
+
+        element.removeEventListener('change', observer.onChange, false);
+        observer.onChange = null;
+
+        this._elementMap.delete(element);
+
+        for (const ancestor of ancestors) {
+            const observers = this._elementAncestorMap.get(ancestor);
+            if (typeof observers === 'undefined') { continue; }
+
+            observers.delete(observer);
+            if (observers.size === 0) {
+                this._elementAncestorMap.delete(ancestor);
+            }
+        }
+    }
+
+    _isObserverStale(observer) {
+        const {element, type, metadata} = observer;
+        const nodeName = element.nodeName.toUpperCase();
+        return !(
+            type === (nodeName === 'INPUT' ? element.type : null) &&
+            this._compareElementMetadata(metadata, this._createElementMetadata(element))
+        );
+    }
+
+    _shouldIgnoreElement(element) {
+        for (const selector of this._ignoreSelectors) {
+            if (element.matches(selector)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    _getAncestors(node) {
+        const root = this._observingElement;
+        const results = [];
+        while (true) {
+            results.push(node);
+            if (node === root) { break; }
+            node = node.parentNode;
+            if (node === null) { break; }
+        }
+        return results;
+    }
+
+    _setElementValue(element, value) {
+        switch (element.nodeName.toUpperCase()) {
+            case 'INPUT':
+                switch (element.type) {
+                    case 'checkbox':
+                        element.checked = value;
+                        break;
+                    case 'text':
+                    case 'number':
+                        element.value = value;
+                        break;
+                }
+                break;
+            case 'TEXTAREA':
+            case 'SELECT':
+                element.value = value;
+                break;
+        }
+    }
+
+    _getElementValue(element) {
+        switch (element.nodeName.toUpperCase()) {
+            case 'INPUT':
+                switch (element.type) {
+                    case 'checkbox':
+                        return !!element.checked;
+                    case 'text':
+                        return `${element.value}`;
+                    case 'number':
+                        return this._getInputNumberValue(element);
+                }
+                break;
+            case 'TEXTAREA':
+            case 'SELECT':
+                return element.value;
+        }
+        return null;
+    }
+
+    _getInputNumberValue(element) {
+        let value = parseFloat(element.value);
+        if (!Number.isFinite(value)) { return 0; }
+
+        let {min, max, step} = element;
+        min = this._stringValueToNumberOrNull(min);
+        max = this._stringValueToNumberOrNull(max);
+        step = this._stringValueToNumberOrNull(step);
+        if (typeof min === 'number') { value = Math.max(value, min); }
+        if (typeof max === 'number') { value = Math.min(value, max); }
+        if (typeof step === 'number' && step !== 0) { value = Math.round(value / step) * step; }
+        return value;
+    }
+
+    _stringValueToNumberOrNull(value) {
+        if (typeof value !== 'string' || value.length === 0) {
+            return null;
+        }
+
+        const number = parseFloat(value);
+        return !Number.isNaN(number) ? number : null;
+    }
+}
diff --git a/ext/mixed/js/task-accumulator.js b/ext/mixed/js/task-accumulator.js
new file mode 100644
index 00000000..5c6fe312
--- /dev/null
+++ b/ext/mixed/js/task-accumulator.js
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2020  Yomichan Authors
+ *
+ * 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 TaskAccumulator {
+    constructor(runTasks) {
+        this._deferPromise = null;
+        this._activePromise = null;
+        this._tasks = [];
+        this._tasksActive = [];
+        this._uniqueTasks = new Map();
+        this._uniqueTasksActive = new Map();
+        this._runTasksBind = this._runTasks.bind(this);
+        this._tasksCompleteBind = this._tasksComplete.bind(this);
+        this._runTasks = runTasks;
+    }
+
+    enqueue(key, data) {
+        if (this._deferPromise === null) {
+            const promise = this._activePromise !== null ? this._activePromise : Promise.resolve();
+            this._deferPromise = promise.then(this._runTasksBind);
+        }
+
+        const task = {data, stale: false};
+        if (key !== null) {
+            const activeTaskInfo = this._uniqueTasksActive.get(key);
+            if (typeof activeTaskInfo !== 'undefined') {
+                activeTaskInfo.stale = true;
+            }
+
+            this._uniqueTasks.set(key, task);
+        } else {
+            this._tasks.push(task);
+        }
+
+        return this._deferPromise;
+    }
+
+    _runTasks() {
+        this._deferPromise = null;
+
+        // Swap
+        [this._tasks, this._tasksActive] = [this._tasksActive, this._tasks];
+        [this._uniqueTasks, this._uniqueTasksActive] = [this._uniqueTasksActive, this._uniqueTasks];
+
+        const promise = this._runTasksAsync();
+        this._activePromise = promise.then(this._tasksCompleteBind);
+        return this._activePromise;
+    }
+
+    async _runTasksAsync() {
+        try {
+            const allTasks = [
+                ...this._tasksActive.map((taskInfo) => [null, taskInfo]),
+                ...this._uniqueTasksActive.entries()
+            ];
+            await this._runTasks(allTasks);
+        } catch (e) {
+            yomichan.logError(e);
+        }
+    }
+
+    _tasksComplete() {
+        this._tasksActive.length = 0;
+        this._uniqueTasksActive.clear();
+        this._activePromise = null;
+    }
+}