node/test/sequential/test-fs-watch.js

// Copyright Joyent, Inc. and other Node contributors.
//
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// copy of this software and associated documentation files (the
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// 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
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// USE OR OTHER DEALINGS IN THE SOFTWARE.

'use strict';
const common = require('../common');
if (common.isIBMi)
  common.skip('IBMi does not support fs.watch()');

const assert = require('assert');
const fs = require('fs');
const path = require('path');

const tmpdir = require('../common/tmpdir');

if (!common.isMainThread)
  common.skip('process.chdir is not available in Workers');

const expectFilePath = common.isWindows ||
                       common.isLinux ||
                       common.isMacOS ||
                       common.isAIX;

const testDir = tmpdir.path;

tmpdir.refresh();

// Because macOS (and possibly other operating systems) can return a watcher
// before it is actually watching, we need to repeat the operation to avoid
// a race condition.
function repeat(fn) {
  setImmediate(fn);
  const interval = setInterval(fn, 5000);
  return interval;
}

{
  const filepath = path.join(testDir, 'watch.txt');

  fs.writeFileSync(filepath, 'hello');

  const watcher = fs.watch(filepath);
  watcher.on('change', common.mustCall(function(event, filename) {
    assert.strictEqual(event, 'change');

    if (expectFilePath) {
      assert.strictEqual(filename, 'watch.txt');
    }
    clearInterval(interval);
    watcher.close();
  }));

  const interval = repeat(() => { fs.writeFileSync(filepath, 'world'); });
}

{
  const filepathAbs = path.join(testDir, 'hasOwnProperty');

  process.chdir(testDir);

  fs.writeFileSync(filepathAbs, 'howdy');

  const watcher =
    fs.watch('hasOwnProperty', common.mustCall(function(event, filename) {
      assert.strictEqual(event, 'change');

      if (expectFilePath) {
        assert.strictEqual(filename, 'hasOwnProperty');
      }
      clearInterval(interval);
      watcher.close();
    }));

  const interval = repeat(() => { fs.writeFileSync(filepathAbs, 'pardner'); });
}

{
  const testsubdir = fs.mkdtempSync(testDir + path.sep);
  const filepath = path.join(testsubdir, 'newfile.txt');

  const watcher =
    fs.watch(testsubdir, common.mustCall(function(event, filename) {
      const renameEv = common.isSunOS || common.isAIX ? 'change' : 'rename';
      assert.strictEqual(event, renameEv);
      if (expectFilePath) {
        assert.strictEqual(filename, 'newfile.txt');
      } else {
        assert.strictEqual(filename, null);
      }
      clearInterval(interval);
      watcher.close();
    }));

  const interval = repeat(() => {
    fs.rmSync(filepath, { force: true });
    const fd = fs.openSync(filepath, 'w');
    fs.closeSync(fd);
  });
}

// https://github.com/joyent/node/issues/2293 - non-persistent watcher should
// not block the event loop
{
  fs.watch(__filename, { persistent: false }, common.mustNotCall());
}

// Whitebox test to ensure that wrapped FSEvent is safe
// https://github.com/joyent/node/issues/6690
{
  if (common.isMacOS || common.isWindows) {
    let oldhandle;
    assert.throws(
      () => {
        const w = fs.watch(__filename, common.mustNotCall());
        oldhandle = w._handle;
        w._handle = { close: w._handle.close };
        w.close();
      },
      {
        name: 'Error',
        code: 'ERR_INTERNAL_ASSERTION',
        message: /^handle must be a FSEvent/,
      }
    );
    oldhandle.close(); // clean up
  }
}

{
  if (common.isMacOS || common.isWindows) {
    let oldhandle;
    assert.throws(
      () => {
        const w = fs.watch(__filename, common.mustNotCall());
        oldhandle = w._handle;
        const protoSymbols =
          Object.getOwnPropertySymbols(Object.getPrototypeOf(w));
        const kFSWatchStart =
          protoSymbols.find((val) => val.toString() === 'Symbol(kFSWatchStart)');
        w._handle = {};
        w[kFSWatchStart]();
      },
      {
        name: 'Error',
        code: 'ERR_INTERNAL_ASSERTION',
        message: /^handle must be a FSEvent/,
      }
    );
    oldhandle.close(); // clean up
  }
}