Simple static location sharing (#7135)

Adds maplibre as a dependency, and behind a labs flag, lets users send and receive [MSC3488](https://github.com/matrix-org/matrix-doc/blob/matthew/location/proposals/3488-location.md) style location shares - with backwards compatibility with old school `m.location` `msgtype` location shares too.

For this to work, you have to define a valid maptile server and API in your config.json's `map_style_url`.

src/components/views/messages/MLocationBody.tsx

@@ -0,0 +1,112 @@
+/*
+Copyright 2021 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 maplibregl from 'maplibre-gl';
+import SdkConfig from '../../../SdkConfig';
+import { replaceableComponent } from "../../../utils/replaceableComponent";
+import { IBodyProps } from "./IBodyProps";
+import { logger } from "matrix-js-sdk/src/logger";
+import { _t } from '../../../languageHandler';
+
+interface IState {
+    error: Error;
+}
+
+@replaceableComponent("views.messages.MLocationBody")
+export default class MLocationBody extends React.Component<IBodyProps, IState> {
+    private map: maplibregl.Map;
+    private coords: GeolocationCoordinates;
+    private description: string;
+
+    constructor(props: IBodyProps) {
+        super(props);
+
+        // unfortunately we're stuck supporting legacy `content.geo_uri`
+        // events until the end of days, or until we figure out mutable
+        // events - so folks can read their old chat history correctly.
+        // https://github.com/matrix-org/matrix-doc/issues/3516
+        const content = this.props.mxEvent.getContent();
+        const uri = content['org.matrix.msc3488.location'] ?
+            content['org.matrix.msc3488.location'].uri :
+            content['geo_uri'];
+
+        this.coords = this.parseGeoUri(uri);
+        this.state = {
+            error: undefined,
+        };
+
+        this.description =
+            content['org.matrix.msc3488.location']?.description ?? content['body'];
+    }
+
+    private parseGeoUri = (uri: string): GeolocationCoordinates => {
+        const m = uri.match(/^\s*geo:(.*?)\s*$/);
+        if (!m) return;
+        const parts = m[1].split(';');
+        const coords = parts[0].split(',');
+        let uncertainty: number;
+        for (const param of parts.slice(1)) {
+            const m = param.match(/u=(.*)/);
+            if (m) uncertainty = parseFloat(m[1]);
+        }
+        return {
+            latitude: parseFloat(coords[0]),
+            longitude: parseFloat(coords[1]),
+            altitude: parseFloat(coords[2]),
+            accuracy: uncertainty,
+            altitudeAccuracy: undefined,
+            heading: undefined,
+            speed: undefined,
+        };
+    };
+
+    componentDidMount() {
+        const config = SdkConfig.get();
+        this.map = new maplibregl.Map({
+            container: this.getBodyId(),
+            style: config.map_style_url,
+            center: [this.coords.longitude, this.coords.latitude],
+            zoom: 13,
+        });
+
+        new maplibregl.Marker()
+            .setLngLat([this.coords.longitude, this.coords.latitude])
+            .addTo(this.map);
+
+        this.map.on('error', (e)=>{
+            logger.error("Failed to load map: check map_style_url in config.json has a valid URL and API key", e.error);
+            this.setState({ error: e.error });
+        });
+    }
+
+    private getBodyId = () => {
+        return `mx_MLocationBody_${this.props.mxEvent.getId()}`;
+    };
+
+    render() {
+        const error = this.state.error ?
+            <div className="mx_EventTile_tileError mx_EventTile_body">
+                { _t("Failed to load map") }
+            </div> : null;
+
+        return <div className="mx_MLocationBody">
+            <div id={this.getBodyId()} className="mx_MLocationBody_map" />
+            { error }
+            <span className="mx_EventTile_body">{ this.description }</span>
+        </div>;
+    }
+}