private _uv_quote_cmd_arg()

in node/toolrunner.ts [488:567]

• 28 lines of code
• 11 McCabe index (conditional complexity)

    private _uv_quote_cmd_arg(arg: string): string {
        // Tool runner wraps child_process.spawn() and needs to apply the same quoting as
        // Node in certain cases where the undocumented spawn option windowsVerbatimArguments
        // is used.
        //
        // Since this function is a port of quote_cmd_arg from Node 4.x (technically, lib UV,
        // see https://github.com/nodejs/node/blob/v4.x/deps/uv/src/win/process.c for details),
        // pasting copyright notice from Node within this function:
        //
        //      Copyright Joyent, Inc. and other Node contributors. All rights reserved.
        //
        //      Permission is hereby granted, free of charge, to any person obtaining a copy
        //      of this software and associated documentation files (the "Software"), to
        //      deal in the Software without restriction, including without limitation the
        //      rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
        //      sell copies of the Software, and to permit persons to whom the Software is
        //      furnished to do so, subject to the following conditions:
        //
        //      The above copyright notice and this permission notice shall be included in
        //      all copies or substantial portions of the Software.
        //
        //      THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
        //      IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
        //      FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
        //      AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
        //      LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
        //      FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
        //      IN THE SOFTWARE.

        if (!arg) {
            // Need double quotation for empty argument
            return '""';
        }

        if (arg.indexOf(' ') < 0 && arg.indexOf('\t') < 0 && arg.indexOf('"') < 0) {
            // No quotation needed
            return arg;
        }

        if (arg.indexOf('"') < 0 && arg.indexOf('\\') < 0) {
            // No embedded double quotes or backslashes, so I can just wrap
            // quote marks around the whole thing.
            return `"${arg}"`;
        }

        // Expected input/output:
        //   input : hello"world
        //   output: "hello\"world"
        //   input : hello""world
        //   output: "hello\"\"world"
        //   input : hello\world
        //   output: hello\world
        //   input : hello\\world
        //   output: hello\\world
        //   input : hello\"world
        //   output: "hello\\\"world"
        //   input : hello\\"world
        //   output: "hello\\\\\"world"
        //   input : hello world\
        //   output: "hello world\\" - note the comment in libuv actually reads "hello world\"
        //                             but it appears the comment is wrong, it should be "hello world\\"
        let reverse: string = '"';
        let quote_hit = true;
        for (let i = arg.length; i > 0; i--) { // walk the string in reverse
            reverse += arg[i - 1];
            if (quote_hit && arg[i - 1] == '\\') {
                reverse += '\\';
            }
            else if (arg[i - 1] == '"') {
                quote_hit = true;
                reverse += '\\';
            }
            else {
                quote_hit = false;
            }
        }

        reverse += '"';
        return reverse.split('').reverse().join('');
    }