tshinnic · August 16, 2011 03:27 · Aug 16, 2011
diff --git a/gistfile1.js b/gistfile1.js
@@ -0,0 +1,92 @@
+//XXX Maybe someday there will be a nice way for user-land modules to
+//      generate pseudo-errno errors?
+
+function errnoException(errno, syscall, message, path) {
+
+  var e = new Error();
+
+  var msg = '';
+  if ( syscall !== undefined ) {
+    msg += syscall + ' ';
+    e.syscall = syscall;
+  }
+
+  if ( errno !== undefined ) {
+    // Try to resolve errno to both a name and a value
+    if ( typeof errno === 'string'  &&  isOwn.call(constants, errno) ) {
+      e.code  = errno;
+      e.errno = constants[errno];
+      msg += errno;
+    } else {
+      e.code = e.errno = errno;
+      msg += errno.toString();
+    }
+  }
+
+  if ( message !== undefined ) {
+    if ( msg !== '' ) { msg += ', '; }
+    msg += message;
+  }
+
+  if ( path !== undefined ) {
+    if ( msg !== '' ) { msg += ' '; }
+    msg += '\'' + path + '\'';
+    e.path = path;
+  }
+
+  e.message = msg;
+
+  return e;
+}
+
+
+
+  Saw real exception     object true  (instanceof Error)
+{ stack: [Getter/Setter],
+  arguments: undefined,
+  type: undefined,
+  message: 'ELOOP, Too many levels of symbolic links \'/home/Tom/study/javascript/node.js/play/test/tmp/testrpx/realpath-3a\'',
+  errno: 40,
+  code: 'ELOOP',
+  path: '/home/Tom/study/javascript/node.js/play/test/tmp/testrpx/realpath-3a' }
+
+  Saw fake exception     object true  (instanceof Error)
+{ stack: [Getter/Setter],
+  arguments: undefined,
+  type: undefined,
+  code: 'ELOOP',
+  errno: 40,
+  path: '/home/Tom/study/javascript/node.js/play/test/tmp/testrpx/realpath-3a',
+  message: 'ELOOP, Too many levels of symbolic links \'/home/Tom/study/javascript/node.js/play/test/tmp/testrpx/realpath-3a\'' }
+
+
+Throwing the 'real' exception
+
+  node.js:134
+          throw e; // process.nextTick error, or 'error' event on first tick
+          ^
+  Error: ELOOP, Too many levels of symbolic links '/home/Tom/study/javascript/node.js/play/test/tmp/testrpx/realpath-3a'
+      at Object.statSync (fs.js:400:18)
+      at realpathX (/home/Tom/study/javascript/node.js/play/pathroot.js:408:18)
+      at test_cyclic_link
+
+Throwing the 'fake' exception
+
+  node.js:134
+          throw e; // process.nextTick error, or 'error' event on first tick
+          ^
+  Error: ELOOP, Too many levels of symbolic links '/home/Tom/study/javascript/node.js/play/test/tmp/testrpx/realpath-3a'
+      at errnoException (/home/Tom/study/javascript/node.js/play/pathroot.js:51:11)
+      at realpathX (/home/Tom/study/javascript/node.js/play/pathroot.js:395:21)
+      at test_cyclic_link_protection (/home/Tom/study/javascript/node.js/play/test/test_realpathx02.js:281:12)
+
+
+
+  lt('  Saw real exception    ', typeof ex, ex instanceof Error);
+  lt(ex);
+
+  var exx = errnoException('ELOOP', undefined,
+              'Too many levels of symbolic links', base);
+  lt('  Saw fake exception    ', typeof exx, exx instanceof Error);
+  lt(exx);
+  throw exx;