chore: chunk filenames when linting C++ files (#34237)

* chore: chunk filenames when linting C++ files

* chore: refactor code for better readability

Co-authored-by: Charles Kerr <charles@charleskerr.com>

* chore: further tweak

* chore: limit all platforms to 4095 characters on command line

* chore: use python3

* Revert "chore: use python3"

Co-authored-by: Charles Kerr <charles@charleskerr.com>
Co-authored-by: Cheng Zhao <zcbenz@gmail.com>

script/lib/utils.js

@@ -1,5 +1,6 @@
 const { GitProcess } = require('dugite');
 const fs = require('fs');
+const os = require('os');
 const path = require('path');
 
 const ELECTRON_DIR = path.resolve(__dirname, '..', '..');
@@ -95,7 +96,35 @@ async function getCurrentBranch (gitDir) {
   return branch.trim();
 }
 
+function chunkFilenames (filenames, offset = 0) {
+  // Windows has a max command line length of 2047 characters, so we can't
+  // provide too many filenames without going over that. To work around that,
+  // chunk up a list of filenames such that it won't go over that limit when
+  // used as args. Other platforms may have higher limits, but 4095 might be
+  // the limit on Linux systems according to `termios(3)`, so cap it there.
+  const MAX_FILENAME_ARGS_LENGTH =
+    (os.platform() === 'win32' ? 2047 : 4095) - offset;
+
+  return filenames.reduce(
+    (chunkedFilenames, filename) => {
+      const currChunk = chunkedFilenames[chunkedFilenames.length - 1];
+      const currChunkLength = currChunk.reduce(
+        (totalLength, _filename) => totalLength + _filename.length + 1,
+        0
+      );
+      if (currChunkLength + filename.length + 1 > MAX_FILENAME_ARGS_LENGTH) {
+        chunkedFilenames.push([filename]);
+      } else {
+        currChunk.push(filename);
+      }
+      return chunkedFilenames;
+    },
+    [[]]
+  );
+}
+
 module.exports = {
+  chunkFilenames,
   getCurrentBranch,
   getElectronExec,
   getOutDir,

script/lint.js

@@ -9,6 +9,8 @@ const klaw = require('klaw');
 const minimist = require('minimist');
 const path = require('path');
 
+const { chunkFilenames } = require('./lib/utils');
+
 const ELECTRON_ROOT = path.normalize(path.dirname(__dirname));
 const SOURCE_ROOT = path.resolve(ELECTRON_ROOT, '..');
 const DEPOT_TOOLS = path.resolve(SOURCE_ROOT, 'third_party', 'depot_tools');
@@ -69,12 +71,11 @@ const LINTERS = [{
   roots: ['shell'],
   test: filename => filename.endsWith('.cc') || (filename.endsWith('.h') && !isObjCHeader(filename)),
   run: (opts, filenames) => {
-    if (opts.fix) {
+    const clangFormatFlags = opts.fix ? ['--fix'] : [];
-      spawnAndCheckExitCode('python3', ['script/run-clang-format.py', '-r', '--fix', ...filenames]);
+    for (const chunk of chunkFilenames(filenames)) {
-    } else {
+      spawnAndCheckExitCode('python3', ['script/run-clang-format.py', ...clangFormatFlags, ...chunk]);
-      spawnAndCheckExitCode('python3', ['script/run-clang-format.py', '-r', ...filenames]);
+      cpplint(chunk);
     }
-    cpplint(filenames);
   }
 }, {
   key: 'objc',

script/run-clang-tidy.ts

@@ -9,6 +9,8 @@ import * as streamJson from 'stream-json';
 import { ignore as streamJsonIgnore } from 'stream-json/filters/Ignore';
 import { streamArray as streamJsonStreamArray } from 'stream-json/streamers/StreamArray';
 
+import { chunkFilenames } from './lib/utils';
+
 const SOURCE_ROOT = path.normalize(path.dirname(__dirname));
 const LLVM_BIN = path.resolve(
   SOURCE_ROOT,
@@ -108,33 +110,6 @@ function getDepotToolsEnv (): NodeJS.ProcessEnv {
   return depotToolsEnv;
 }
 
-function chunkFilenames (filenames: string[], offset: number = 0): string[][] {
-  // Windows has a max command line length of 2047 characters, so we can't
-  // provide too many filenames without going over that. To work around that,
-  // chunk up a list of filenames such that it won't go over that limit when
-  // used as args. Use a much higher limit on other platforms which will
-  // effectively be a no-op.
-  const MAX_FILENAME_ARGS_LENGTH =
-    PLATFORM === 'win32' ? 2047 - offset : 100 * 1024;
-
-  return filenames.reduce(
-    (chunkedFilenames: string[][], filename) => {
-      const currChunk = chunkedFilenames[chunkedFilenames.length - 1];
-      const currChunkLength = currChunk.reduce(
-        (totalLength, _filename) => totalLength + _filename.length + 1,
-        0
-      );
-      if (currChunkLength + filename.length + 1 > MAX_FILENAME_ARGS_LENGTH) {
-        chunkedFilenames.push([filename]);
-      } else {
-        currChunk.push(filename);
-      }
-      return chunkedFilenames;
-    },
-    [[]]
-  );
-}
-
 async function runClangTidy (
   outDir: string,
   filenames: string[],