element-web/src/components/structures/MainSplit.js

/*
Copyright 2018 New Vector Ltd
Copyright 2019 The Matrix.org Foundation C.I.C.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

import React from 'react';
import ResizeHandle from '../views/elements/ResizeHandle';
import {Resizer, FixedDistributor} from '../../resizer';

export default class MainSplit extends React.Component {
    constructor(props) {
        super(props);
        this._setResizeContainerRef = this._setResizeContainerRef.bind(this);
        this._onResized = this._onResized.bind(this);
    }

    _onResized(size) {
        window.localStorage.setItem("mx_rhs_size", size);
        if (this.props.resizeNotifier) {
            this.props.resizeNotifier.notifyRightHandleResized();
        }
    }

    _createResizer() {
        const classNames = {
            handle: "mx_ResizeHandle",
            vertical: "mx_ResizeHandle_vertical",
            reverse: "mx_ResizeHandle_reverse",
        };
        const resizer = new Resizer(
            this.resizeContainer,
            FixedDistributor,
            {onResized: this._onResized},
        );
        resizer.setClassNames(classNames);
        let rhsSize = window.localStorage.getItem("mx_rhs_size");
        if (rhsSize !== null) {
            rhsSize = parseInt(rhsSize, 10);
        } else {
            rhsSize = 350;
        }
        resizer.forHandleAt(0).resize(rhsSize);

        resizer.attach();
        this.resizer = resizer;
    }

    _setResizeContainerRef(div) {
        this.resizeContainer = div;
    }

    componentDidMount() {
        if (this.props.panel) {
            this._createResizer();
        }
    }

    componentWillUnmount() {
        if (this.resizer) {
            this.resizer.detach();
            this.resizer = null;
        }
    }

    componentDidUpdate(prevProps) {
        const wasPanelSet = this.props.panel && !prevProps.panel;
        const wasPanelCleared = !this.props.panel && prevProps.panel;

        if (this.resizeContainer && wasPanelSet) {
            // The resizer can only be created when **both** expanded and the panel is
            // set. Once both are true, the container ref will mount, which is required
            // for the resizer to work.
            this._createResizer();
        } else if (this.resizer && wasPanelCleared) {
            this.resizer.detach();
            this.resizer = null;
        }
    }

    render() {
        const bodyView = React.Children.only(this.props.children);
        const panelView = this.props.panel;

        const hasResizer = !this.props.collapsedRhs && panelView;

        let children;
        if (hasResizer) {
            children = <React.Fragment>
                <ResizeHandle reverse={true} />
                { panelView }
            </React.Fragment>;
        }

        return <div className="mx_MainSplit" ref={hasResizer ? this._setResizeContainerRef : undefined}>
            { bodyView }
            { children }
        </div>;
    }
}