From d1dd8a8e4ded2806c868a63aeee5cff81cf1579d Mon Sep 17 00:00:00 2001
From: David Glasser <glasser@meteor.com>
Date: Thu, 11 Apr 2013 17:11:45 -0700
Subject: [PATCH] Refactor Avi's improved Meteor.Error to make it possible to
 use for other Error subclasses.

---
 packages/livedata/livedata_common.js | 73 ++++++++++------------------
 packages/meteor/errors.js            | 39 +++++++++++++++
 packages/meteor/package.js           |  1 +
 3 files changed, 65 insertions(+), 48 deletions(-)
 create mode 100644 packages/meteor/errors.js

diff --git a/packages/livedata/livedata_common.js b/packages/livedata/livedata_common.js
index 15344c9629..e2543581fc 100644
--- a/packages/livedata/livedata_common.js
+++ b/packages/livedata/livedata_common.js
@@ -119,55 +119,32 @@ Meteor._CurrentInvocation = new Meteor.EnvironmentVariable;
 // The DDP client manually puts these into Meteor.Error objects. (We don't use
 // EJSON.addType here because the type is determined by location in the
 // protocol, not text on the wire.)
-Meteor.Error = function (error, reason, details) {
-  var self = this;
+Meteor.Error = Meteor.makeErrorType(
+  "Meteor.Error",
+  function (error, reason, details) {
+    var self = this;
 
-  // Ensure we get a proper stack trace in most Javascript environments
-  if (Error.captureStackTrace) {
-    // V8 environments (Chrome and Node.js)
-    Error.captureStackTrace(self, Meteor.Error);
-  } else {
-    // Firefox
-    var e = new Error;
-    e.__proto__ = Meteor.Error.prototype;
-    if (e instanceof Meteor.Error)
-      self = e;
-  }
-  // Safari magically works.
+    // Currently, a numeric code, likely similar to a HTTP code (eg,
+    // 404, 500). That is likely to change though.
+    self.error = error;
 
-  // Currently, a numeric code, likely similar to a HTTP code (eg,
-  // 404, 500). That is likely to change though.
-  self.error = error;
+    // Optional: A short human-readable summary of the error. Not
+    // intended to be shown to end users, just developers. ("Not Found",
+    // "Internal Server Error")
+    self.reason = reason;
 
-  // Optional: A short human-readable summary of the error. Not
-  // intended to be shown to end users, just developers. ("Not Found",
-  // "Internal Server Error")
-  self.reason = reason;
+    // Optional: Additional information about the error, say for
+    // debugging. It might be a (textual) stack trace if the server is
+    // willing to provide one. The corresponding thing in HTTP would be
+    // the body of a 404 or 500 response. (The difference is that we
+    // never expect this to be shown to end users, only developers, so
+    // it doesn't need to be pretty.)
+    self.details = details;
 
-  // Optional: Additional information about the error, say for
-  // debugging. It might be a (textual) stack trace if the server is
-  // willing to provide one. The corresponding thing in HTTP would be
-  // the body of a 404 or 500 response. (The difference is that we
-  // never expect this to be shown to end users, only developers, so
-  // it doesn't need to be pretty.)
-  self.details = details;
-
-  // This is what gets displayed at the top of a stack trace. Current
-  // format is "[404]" (if no reason is set) or "File not found [404]"
-  if (self.reason)
-    self.message = self.reason + ' [' + self.error + ']';
-  else
-    self.message = '[' + self.error + ']';
-
-  return self;
-};
-
-// http://davidshariff.com/blog/javascript-inheritance-patterns/
-var inherits = function (child, parent) {
-  var tmp = function () {};
-  tmp.prototype = parent.prototype;
-  child.prototype = new tmp;
-  child.prototype.constructor = child;
-};
-
-inherits(Meteor.Error, Error);
\ No newline at end of file
+    // This is what gets displayed at the top of a stack trace. Current
+    // format is "[404]" (if no reason is set) or "File not found [404]"
+    if (self.reason)
+      self.message = self.reason + ' [' + self.error + ']';
+    else
+      self.message = '[' + self.error + ']';
+  });
diff --git a/packages/meteor/errors.js b/packages/meteor/errors.js
new file mode 100644
index 0000000000..7a63778556
--- /dev/null
+++ b/packages/meteor/errors.js
@@ -0,0 +1,39 @@
+// http://davidshariff.com/blog/javascript-inheritance-patterns/
+var inherits = function (child, parent) {
+  var tmp = function () {};
+  tmp.prototype = parent.prototype;
+  child.prototype = new tmp;
+  child.prototype.constructor = child;
+};
+
+// Makes an error subclass which properly contains a stack trace in most
+// environments. constructor can set fields on `this` (and should probably set
+// `message`, which is what gets displayed at the top of a stack trace).
+Meteor.makeErrorType = function (name, constructor) {
+  var errorClass = function (/*arguments*/) {
+    var self = this;
+
+    // Ensure we get a proper stack trace in most Javascript environments
+    if (Error.captureStackTrace) {
+      // V8 environments (Chrome and Node.js)
+      Error.captureStackTrace(self, errorClass);
+    } else {
+      // Firefox
+      var e = new Error;
+      e.__proto__ = errorClass.prototype;
+      if (e instanceof errorClass)
+        self = e;
+    }
+    // Safari magically works.
+
+    constructor.apply(self, arguments);
+
+    self.errorType = name;
+
+    return self;
+  };
+
+  inherits(errorClass, Error);
+
+  return errorClass;
+};
diff --git a/packages/meteor/package.js b/packages/meteor/package.js
index 7b0ab1a2e8..25251f9937 100644
--- a/packages/meteor/package.js
+++ b/packages/meteor/package.js
@@ -34,6 +34,7 @@ Package.on_use(function (api, where) {
   api.add_files('server_environment.js', 'server');
   api.add_files('helpers.js', ['client', 'server']);
   api.add_files('timers.js', ['client', 'server']);
+  api.add_files('errors.js', ['client', 'server']);
   api.add_files('fiber_helpers.js', 'server');
 
   // dynamic variables, bindEnvironment