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/**
* @fileoverview Remove macros from SpiderMonkey's self-hosted JS.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
*/
"use strict";
const path = require("path");
const fs = require("fs");
const selfHostedRegex = /js\/src\/builtin\/.*?\.js$/;
const macroRegex =
/\s*\#(if|ifdef|else|elif|endif|include|define|undef|error).*/;
function isSelfHostedFile(filename) {
if (path.win32) {
filename = filename.split(path.sep).join("/");
}
return selfHostedRegex.test(filename);
}
function tryReadFile(filePath) {
if (!path.isAbsolute(filePath)) {
return "";
}
if (!fs.existsSync(filePath)) {
// Safely handle the case when the file wasn't found, because throwing
// errors can lead to confusing result when used with ESLint.
return "";
}
return fs.readFileSync(filePath, "utf-8");
}
// Adjust the range of fixes to match the original source code.
function createFix(lines, message) {
let { line, column, fix } = message;
// Line and column are 1-based. Make sure we got a valid input.
if (line <= 0 || column <= 0) {
return null;
}
// Reject to create a fix when the line is out of range for some reason.
if (line > lines.length) {
return null;
}
// Find the absolute start position of the line in the original file.
let startOfLine = 0;
for (let i = 0; i < line - 1; ++i) {
// Add the length of the line, including its line separator.
startOfLine += lines[i].length + "\n".length;
}
// Add the 1-based column to the start of line to get the start position.
let start = startOfLine + (column - 1);
// Add the fix range to get the end position.
let end = start + (fix.range[1] - fix.range[0]);
// And finally return the new fix object.
return { text: fix.text, range: [start, end] };
}
module.exports = {
preprocess(text, filename) {
if (!isSelfHostedFile(filename)) {
return [text];
}
let lines = text.split(/\n/);
for (let i = 0; i < lines.length; i++) {
if (!macroRegex.test(lines[i])) {
// No macro here, nothing to do.
continue;
}
for (; i < lines.length; i++) {
// The macro isn't correctly indented, so we need to instruct
// prettier to ignore them.
lines[i] = "// prettier-ignore -- " + lines[i];
// If the line ends with a backslash (\), the next line
// is also part of part of the macro.
if (!lines[i].endsWith("\\")) {
break;
}
}
}
return [lines.join("\n")];
},
postprocess(messages, filename) {
// Don't attempt to create fixes for any non-selfhosted files.
if (!isSelfHostedFile(filename)) {
return [].concat(...messages);
}
let lines = null;
let result = [];
for (let message of messages.flat()) {
if (message.fix) {
if (lines === null) {
lines = tryReadFile(filename).split(/\n/);
}
let fix = createFix(lines, message);
if (fix) {
message.fix = fix;
} else {
// We couldn't create a fix, so we better remove the passed in fix,
// because its range points to the preprocessor output, but the post-
// processor must translate it into a range of the original source.
delete message.fix;
}
}
result.push(message);
}
return result;
},
supportsAutofix: true,
};