lib/handlers/formatting.js

// Copyright (c) 2018, Compiler Explorer Authors
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
//     * Redistributions of source code must retain the above copyright notice,
//       this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above copyright
//       notice, this list of conditions and the following disclaimer in the
//       documentation and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.

const exec = require('../exec'),
    _ = require('underscore'),
    logger = require('../logger').logger;

class Formatter {
    constructor(ceProps) {
        this.tools = {};
        this.ceProps = ceProps;
        const formatters = _.compact(ceProps('formatters', '').split(':'));
        _.each(formatters, this.fetchToolInfo.bind(this));
    }

    async fetchToolInfo(formatter) {
        const exe = this.ceProps(`formatter.${formatter}.exe`);
        if (!exe) {
            logger.warn(`Formatter ${formatter} does not have a valid executable. Skipping...`);
            return;
        }
        const versionArg = this.ceProps(`formatter.${formatter}.version`, '--version');
        const versionRe = this.ceProps(`formatter.${formatter}.versionRe`, '.*');
        try {
            const result = await this.run(exe, [versionArg], {});
            const match = result.stdout.match(versionRe);
            this.tools[formatter] = {
                exe: exe,
                version: match ? match[0] : result.stdout,
                name: this.ceProps(`formatter.${formatter}.name`, exe),
                styles: this.ceProps(`formatter.${formatter}.styles`, '').split(':'),
            };
        } catch (err) {
            logger.warn(`Error while fetching tool info for ${exe}:`, {err});
        }
    }

    supportsStyle(tool, style) {
        return tool.styles.includes(style);
    }

    validateFormatRequest(req, res) {
        let requestedTool = this.tools[req.params.tool];
        if (!requestedTool) {
            res.status(422); // Unprocessable Entity
            res.send({
                exit: 2,
                answer: 'Tool not supported',
            });
            return false;
        }
        // Only clang supported for now
        if (!req.body || !req.body.source) {
            res.send({
                exit: 0,
                answer: '',
            });
            return false;
        }
        // Hardcoded supported clang-format base styles.
        // Will need a bit of work if we want to support other tools!
        if (!this.supportsStyle(requestedTool, req.body.base)) {
            res.status(422); // Unprocessable Entity
            res.send({
                exit: 3,
                answer: 'Base style not supported',
            });
            return false;
        }
        return true;
    }

    async formatHandler(req, res) {
        if (!this.validateFormatRequest(req, res)) return;
        try {
            const result = await this.formatCode(
                this.tools[req.params.tool],
                [`-style=${req.body.base}`],
                {input: req.body.source});
            res.send({
                exit: result.code,
                answer: result.stdout || '',
            });
        } catch (ex) {
            // Unexpected problem when running the formatter
            res.status(500);
            res.send({
                exit: 1,
                thrown: true,
                answer: ex.message || 'Internal server error',
            });
        }
    }

    async run(exe, args, options) {
        return exec.execute(exe, args, options);
    }

    async formatCode(tool, args, options) {
        return this.run(tool.exe, args, options);
    }

    listHandler(req, res) {
        return res.send(_.map(this.tools, tool => ({name: tool.name, version: tool.version})));
    }
}

module.exports = Formatter;