Move Add-on SDK source to toolkit/jetpack

1 files changed, 225 insertions, 0 deletions

diff --git a/toolkit/jetpack/method/core.js b/toolkit/jetpack/method/core.js
new file mode 100644
index 000000000..a6a5261e6
--- /dev/null
+++ b/toolkit/jetpack/method/core.js
@@ -0,0 +1,225 @@
+"use strict";
+
+var defineProperty = Object.defineProperty || function(object, name, property) {
+  object[name] = property.value
+  return object
+}
+
+// Shortcut for `Object.prototype.toString` for faster access.
+var typefy = Object.prototype.toString
+
+// Map to for jumping from typeof(value) to associated type prefix used
+// as a hash in the map of builtin implementations.
+var types = { "function": "Object", "object": "Object" }
+
+// Array is used to save method implementations for the host objects in order
+// to avoid extending them with non-primitive values that could cause leaks.
+var host = []
+// Hash map is used to save method implementations for builtin types in order
+// to avoid extending their prototypes. This also allows to share method
+// implementations for types across diff contexts / frames / compartments.
+var builtin = {}
+
+function Primitive() {}
+function ObjectType() {}
+ObjectType.prototype = new Primitive()
+function ErrorType() {}
+ErrorType.prototype = new ObjectType()
+
+var Default = builtin.Default = Primitive.prototype
+var Null = builtin.Null = new Primitive()
+var Void = builtin.Void = new Primitive()
+builtin.String = new Primitive()
+builtin.Number = new Primitive()
+builtin.Boolean = new Primitive()
+
+builtin.Object = ObjectType.prototype
+builtin.Error = ErrorType.prototype
+
+builtin.EvalError = new ErrorType()
+builtin.InternalError = new ErrorType()
+builtin.RangeError = new ErrorType()
+builtin.ReferenceError = new ErrorType()
+builtin.StopIteration = new ErrorType()
+builtin.SyntaxError = new ErrorType()
+builtin.TypeError = new ErrorType()
+builtin.URIError = new ErrorType()
+
+
+function Method(hint) {
+  /**
+  Private Method is a callable private name that dispatches on the first
+  arguments same named Method:
+
+      method(object, ...rest) => object[method](...rest)
+
+  Optionally hint string may be provided that will be used in generated names
+  to ease debugging.
+
+  ## Example
+
+      var foo = Method()
+
+      // Implementation for any types
+      foo.define(function(value, arg1, arg2) {
+        // ...
+      })
+
+      // Implementation for a specific type
+      foo.define(BarType, function(bar, arg1, arg2) {
+        // ...
+      })
+  **/
+
+  // Create an internal unique name if `hint` is provided it is used to
+  // prefix name to ease debugging.
+  var name = (hint || "") + "#" + Math.random().toString(32).substr(2)
+
+  function dispatch(value) {
+    // Method dispatches on type of the first argument.
+    // If first argument is `null` or `void` associated implementation is
+    // looked up in the `builtin` hash where implementations for built-ins
+    // are stored.
+    var type = null
+    var method = value === null ? Null[name] :
+                 value === void(0) ? Void[name] :
+                 // Otherwise attempt to use method with a generated private
+                 // `name` that is supposedly in the prototype chain of the
+                 // `target`.
+                 value[name] ||
+                 // Otherwise assume it's one of the built-in type instances,
+                 // in which case implementation is stored in a `builtin` hash.
+                 // Attempt to find a implementation for the given built-in
+                 // via constructor name and method name.
+                 ((type = builtin[(value.constructor || "").name]) &&
+                  type[name]) ||
+                 // Otherwise assume it's a host object. For host objects
+                 // actual method implementations are stored in the `host`
+                 // array and only index for the implementation is stored
+                 // in the host object's prototype chain. This avoids memory
+                 // leaks that otherwise could happen when saving JS objects
+                 // on host object.
+                 host[value["!" + name] || void(0)] ||
+                 // Otherwise attempt to lookup implementation for builtins by
+                 // a type of the value. This basically makes sure that all
+                 // non primitive values will delegate to an `Object`.
+                 ((type = builtin[types[typeof(value)]]) && type[name])
+
+
+    // If method implementation for the type is still not found then
+    // just fallback for default implementation.
+    method = method || Default[name]
+
+
+    // If implementation is still not found (which also means there is no
+    // default) just throw an error with a descriptive message.
+    if (!method) throw TypeError("Type does not implements method: " + name)
+
+    // If implementation was found then just delegate.
+    return method.apply(method, arguments)
+  }
+
+  // Make `toString` of the dispatch return a private name, this enables
+  // method definition without sugar:
+  //
+  //    var method = Method()
+  //    object[method] = function() { /***/ }
+  dispatch.toString = function toString() { return name }
+
+  // Copy utility methods for convenient API.
+  dispatch.implement = implementMethod
+  dispatch.define = defineMethod
+
+  return dispatch
+}
+
+// Create method shortcuts form functions.
+var defineMethod = function defineMethod(Type, lambda) {
+  return define(this, Type, lambda)
+}
+var implementMethod = function implementMethod(object, lambda) {
+  return implement(this, object, lambda)
+}
+
+// Define `implement` and `define` polymorphic methods to allow definitions
+// and implementations through them.
+var implement = Method("implement")
+var define = Method("define")
+
+
+function _implement(method, object, lambda) {
+  /**
+  Implements `Method` for the given `object` with a provided `implementation`.
+  Calling `Method` with `object` as a first argument will dispatch on provided
+  implementation.
+  **/
+  return defineProperty(object, method.toString(), {
+    enumerable: false,
+    configurable: false,
+    writable: false,
+    value: lambda
+  })
+}
+
+function _define(method, Type, lambda) {
+  /**
+  Defines `Method` for the given `Type` with a provided `implementation`.
+  Calling `Method` with a first argument of this `Type` will dispatch on
+  provided `implementation`. If `Type` is a `Method` default implementation
+  is defined. If `Type` is a `null` or `undefined` `Method` is implemented
+  for that value type.
+  **/
+
+  // Attempt to guess a type via `Object.prototype.toString.call` hack.
+  var type = Type && typefy.call(Type.prototype)
+
+  // If only two arguments are passed then `Type` is actually an implementation
+  // for a default type.
+  if (!lambda) Default[method] = Type
+  // If `Type` is `null` or `void` store implementation accordingly.
+  else if (Type === null) Null[method] = lambda
+  else if (Type === void(0)) Void[method] = lambda
+  // If `type` hack indicates built-in type and type has a name us it to
+  // store a implementation into associated hash. If hash for this type does
+  // not exists yet create one.
+  else if (type !== "[object Object]" && Type.name) {
+    var Bulitin = builtin[Type.name] || (builtin[Type.name] = new ObjectType())
+    Bulitin[method] = lambda
+  }
+  // If `type` hack indicates an object, that may be either object or any
+  // JS defined "Class". If name of the constructor is `Object`, assume it's
+  // built-in `Object` and store implementation accordingly.
+  else if (Type.name === "Object")
+    builtin.Object[method] = lambda
+  // Host objects are pain!!! Every browser does some crazy stuff for them
+  // So far all browser seem to not implement `call` method for host object
+  // constructors. If that is a case here, assume it's a host object and
+  // store implementation in a `host` array and store `index` in the array
+  // in a `Type.prototype` itself. This avoids memory leaks that could be
+  // caused by storing JS objects on a host objects.
+  else if (Type.call === void(0)) {
+    var index = host.indexOf(lambda)
+    if (index < 0) index = host.push(lambda) - 1
+    // Prefix private name with `!` so it can be dispatched from the method
+    // without type checks.
+    implement("!" + method, Type.prototype, index)
+  }
+  // If Got that far `Type` is user defined JS `Class`. Define private name
+  // as hidden property on it's prototype.
+  else
+    implement(method, Type.prototype, lambda)
+}
+
+// And provided implementations for a polymorphic equivalents.
+_define(define, _define)
+_define(implement, _implement)
+
+// Define exports on `Method` as it's only thing being exported.
+Method.implement = implement
+Method.define = define
+Method.Method = Method
+Method.method = Method
+Method.builtin = builtin
+Method.host = host
+
+module.exports = Method