1 files changed, 128 insertions, 0 deletions
diff --git a/tools/lint/eslint/eslint-plugin-spidermonkey-js/lib/processors/self-hosted.js b/tools/lint/eslint/eslint-plugin-spidermonkey-js/lib/processors/self-hosted.js
new file mode 100644
index 0000000000..8a607ffbe5
--- /dev/null
+++ b/tools/lint/eslint/eslint-plugin-spidermonkey-js/lib/processors/self-hosted.js
@@ -0,0 +1,128 @@
+/**
+ * @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
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+"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).*/;
+
+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,
+};