compiler-explorer/shared/common-utils.ts

// Copyright (c) 2022, 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.

export function isString(x: any): x is string {
    return typeof x === 'string' || x instanceof String;
}

// Object.keys is typed as returning :string[] for some reason
// This util is for cases where the key is a union of a few possible keys and we
// want the resulting array properly typed.
export function keys<K extends string | number | symbol>(o: Partial<Record<K, any>>): K[] {
    return Object.keys(o) as K[];
}

export function unique<V>(arr: V[]): V[] {
    return [...new Set(arr)];
}

export function intersection<V>(a: V[], b: V[]): V[] {
    const B = new Set(b);
    return [...a].filter(item => B.has(item));
}

// arr.filter(x => x !== null) returns a (T | null)[] even though it is a T[]
// Apparently the idiomatic solution is arr.filter((x): x is T => x !== null), but this is shorter (and the type
// predicate also isn't type checked so it doesn't seem safe to me)
export function remove<U, V extends U>(arr: U[], v: V) {
    return arr.filter(item => item !== v) as Exclude<U, V extends null | undefined ? V : never>[];
}

// https://www.typescriptlang.org/play?#code/KYDwDg9gTgLgBAMwK4DsDGMCWEVysAWwgDdgAeAVQBo4A1OUGYFAEwGc4KA+ACgEMoUAFycA2gF0axEbQCUcAN4AoOKrzAYSKLgFQAdAkwAbJlB6YmBOAF4ucC4TgBCa9bjF5fDgFEQaI0gs5NR0DCBMrBwoSEZGcAA+cKhBhijALHAA-KEiaaRQXBIA3EoAvkpKQf4CwHBoOGzwuiI8jVCYKADmCXDRsbLFFfUojXAgNupEpPyCNH1GsiUA9EtqcAB6mUMN8ACeE-hTwDNQNABECBAQZ4tKK2ubFUA

// For Array.prototype.sort
export function basic_comparator<T>(a: T, b: T) {
    if (a < b) {
        return -1;
    }
    if (a > b) {
        return 1;
    }
    return 0;
}

// https://stackoverflow.com/questions/41253310/typescript-retrieve-element-type-information-from-array-type
export type ElementType<ArrayType extends readonly unknown[]> = ArrayType extends readonly (infer T)[] ? T : never;

const EscapeMap = {
    '&': '&amp;',
    '<': '&lt;',
    '>': '&gt;',
    '"': '&quot;',
    "'": '&#x27;',
    '`': '&#x60;',
};
const EscapeRE = new RegExp(`(?:${Object.keys(EscapeMap).join('|')})`, 'g');

export function escapeHTML(text: string) {
    return text.replace(EscapeRE, str => EscapeMap[str as keyof typeof EscapeMap]);
}

function splitIntoChunks(s: string, chunkSize: number): string[] {
    const chunks: string[] = [];
    const isNegative = s.slice(0, 1) === '-';
    if (isNegative) {
        s = s.slice(1);
    }
    const firstChunkLength = s.length % chunkSize;
    if (firstChunkLength !== 0) {
        chunks.push(s.slice(0, firstChunkLength));
    }
    for (let i = firstChunkLength; i < s.length; i += chunkSize) {
        chunks.push(s.slice(i, i + chunkSize));
    }
    if (isNegative) {
        chunks[0] = '-' + (chunks[0] ?? '');
    }
    return chunks;
}

export function addDigitSeparator(n: string, digitSeparator: string, chunkSize: number): string {
    return splitIntoChunks(n, chunkSize).join(digitSeparator);
}

class ArgumentParser {
    private rest: string;
    private position: number;
    private inDoubleQuotes: boolean;
    private readonly results: string[];

    constructor(str: string) {
        this.rest = str.trim();
        this.position = 0;
        this.inDoubleQuotes = false;
        this.results = [];
    }

    private addResult(result: string) {
        if (this.results[this.position] === undefined) {
            this.results[this.position] = result;
        } else {
            this.results[this.position] += result;
        }
    }

    private handleEscapeCharacter() {
        if (this.rest.length < 2) {
            this.addResult('\\');
        } else {
            if (this.rest.charAt(1) !== '\n') {
                this.addResult(this.rest.charAt(1));
            }
        }
        this.rest = this.rest.slice(2);
    }

    private handleSingleQuotes() {
        let quotePos = this.rest.indexOf("'", 1);
        if (quotePos === -1) quotePos = this.rest.length;
        this.addResult(this.rest.slice(1, quotePos));
        this.rest = this.rest.slice(quotePos + 1);
    }

    private handleDoubleQuotes() {
        const match = /["\\]/.exec(this.rest);
        const matchEnd = match ? match.index : this.rest.length;

        this.addResult(this.rest.slice(0, matchEnd));

        if (match && match[0] === '\\') {
            this.rest = this.rest.slice(matchEnd);
            this.handleEscapeCharacter();
        } else {
            this.rest = this.rest.slice(matchEnd + 1);
            this.inDoubleQuotes = false;
        }
    }

    private handleWhitespace() {
        const wsMatch = /^\s+/.exec(this.rest);
        if (wsMatch) {
            this.rest = this.rest.slice(wsMatch[0].length);
            ++this.position;
        }
    }

    private handleNonDoubleQuote(nextMatch: RegExpExecArray) {
        this.addResult(this.rest.slice(0, nextMatch.index));
        this.rest = this.rest.slice(nextMatch.index);

        switch (nextMatch[0]) {
            case '\\':
                this.handleEscapeCharacter();
                break;
            case "'":
                this.handleSingleQuotes();
                break;
            case '"':
                this.rest = this.rest.slice(1);
                this.inDoubleQuotes = true;
                break;
            default:
                break;
        }
    }

    public exec(): string[] {
        while (this.rest) {
            if (this.inDoubleQuotes) {
                this.handleDoubleQuotes();
                continue;
            }

            this.handleWhitespace();

            const nextMatch = /[\s'"\\]/.exec(this.rest);
            if (!nextMatch) {
                this.addResult(this.rest);
                this.rest = '';
                continue;
            }

            this.handleNonDoubleQuote(nextMatch);
        }
        return this.results;
    }
}

export function splitArguments(str = ''): string[] {
    return new ArgumentParser(str).exec();
}

export function capitaliseFirst(str: string): string {
    if (str.length === 0) return str;
    return str.charAt(0).toUpperCase() + str.slice(1);
}

export const ce_temp_prefix = 'compiler-explorer-compiler';

// Matches everything up to and through a CE temp dir, `.../<ce_temp_prefix><suffix>/`.
// We key off the ce_temp_prefix marker, NOT the live os.tmpdir(): the temp root varies
// by host/config (macOS /var vs /private/var, an execution.tempDirRoot elsewhere) and
// the path being masked may have been recorded under a different tmpdir than this one.
// The marker is the only invariant — it's the same constant we create the dir with.
// `(?:[A-Za-z]:)?` + `/` handles Windows too; `[^/\s]+` confines the match to one
// non-empty path token so an embedded `-I/tmp/<prefix>XXX/inc` still masks to
// `-I/app/inc` (real temp paths never have empty `//` segments).
// A user path that itself contains a `<ce_temp_prefix>...` segment would be masked too,
// but that only affects displayed output (never what's compiled/executed) and needs a
// deliberately odd dir name, so it's not worth a costlier scheme to prevent.
const TEMPDIR_RE = new RegExp(`(?:[A-Za-z]:)?/(?:[^/\\s]+/)*${ce_temp_prefix}[\\w.-]*/`);

/**
 * Rewrites a CE temp dir down to `/app/`, and stops there. That is the path the compiler
 * is really given, and what `__FILE__` and friends expand to, so anything that shows the
 * user a command line has to keep the prefix. Use maskRootdir() for output lines instead.
 */
export function maskRootdirKeepingAppPrefix(filepath: string): string {
    // TODO: this falsy guard is load-bearing against runtime `undefined` that the types
    // don't catch — not declared `string | undefined` callers (TS would reject those),
    // but type holes: a JSON.parse(...) result typed `any` (base-compiler cleanup) and a
    // Record<number,string> index that's really `undefined` when the key is missing
    // (noUncheckedIndexedAccess is off). Tighten those two sites, then this can go.
    if (!filepath) return filepath;
    // TEMPDIR_RE has a repeated path-segment group that backtracks on long input, and this
    // runs on every output line. Gate it behind a cheap linear substring check: the regex
    // cannot match without the marker anyway.
    return filepath.includes(ce_temp_prefix) ? filepath.replace(TEMPDIR_RE, '/app/') : filepath;
}

// As TEMPDIR_RE, but global, and the trailing slash is optional so a bare temp dir counts as a path. Both
// differences only matter for free-form text: an argv entry holds one path and the temp dir is always the
// prefix of a file within it, neither of which holds for something like `-L/tmp/<prefix>X -Wl,-rpath,...`.
const TEMPDIR_TEXT_RE = new RegExp(`(?:[A-Za-z]:)?/(?:[^/\\s]+/)*${ce_temp_prefix}[\\w.-]*(/?)`, 'g');

/**
 * Rewrites every CE temp dir in a string that may hold several paths — an environment value such as
 * LDFLAGS, rather than a single argument. Use maskRootdirKeepingAppPrefix() for one path on its own.
 */
export function maskRootdirsInText(text: string): string {
    if (!text) return text;
    // Same cheap guard as above: the regex cannot match without the marker, and it backtracks on long input.
    return text.includes(ce_temp_prefix) ? text.replace(TEMPDIR_TEXT_RE, '/app$1') : text;
}