Generate all runtime files from dart.

tool/input_sdk/private/types.dart

+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/// This library defines the representation of runtime types.
+part of dart._runtime;
+
+/// The Symbol for storing type arguments on a specialized generic type.
+final _mixins = JS('', 'Symbol("mixins")');
+@JSExportName('implements')
+final implements_ = JS('', 'Symbol("implements")');
+final metadata = JS('', 'Symbol("metadata")');
+
+
+///
+/// Types in dart are represented at runtime as follows.
+///   - Normal nominal types, produced from classes, are represented
+///     at runtime by the JS class of which they are an instance.
+///     If the type is the result of instantiating a generic class,
+///     then the "classes" module manages the association between the
+///     instantiated class and the original class declaration
+///     and the type arguments with which it was instantiated.  This
+///     assocation can be queried via the "classes" module".
+///
+///   - All other types are represented as instances of class TypeRep,
+///     defined in this module.
+///     - Dynamic, Void, and Bottom are singleton instances of sentinal
+///       classes.
+///     - Function types are instances of subclasses of AbstractFunctionType.
+///
+/// Function types are represented in one of two ways:
+///   - As an instance of FunctionType.  These are eagerly computed.
+///   - As an instance of TypeDef.  The TypeDef representation lazily
+///     computes an instance of FunctionType, and delegates to that instance.
+///
+/// All types satisfy the following interface:
+///  get String name;
+///  String toString();
+///
+///
+final TypeRep = JS('', '''
+  class TypeRep extends $LazyTagged(() => $Type) {
+    get name() {return this.toString();}
+  }
+''');
+
+final Dynamic = JS('', '''
+  class Dynamic extends $TypeRep {
+    toString() { return "dynamic"; }
+  }
+''');
+@JSExportName('dynamic')
+final dynamicR = JS('', 'new $Dynamic()');
+
+final Void = JS('', '''
+  class Void extends $TypeRep {
+    toString() { return "void"; }
+  }
+''');
+
+@JSExportName('void')
+final voidR = JS('', 'new $Void()');
+
+final Bottom = JS('', '''
+  class Bottom extends $TypeRep {
+    toString() { return "bottom"; }
+  }
+''');
+final bottom = JS('', 'new $Bottom()');
+
+final JSObject = JS('', '''
+  class JSObject extends $TypeRep {
+    toString() { return "NativeJavaScriptObject"; }
+  }
+''');
+final jsobject = JS('', 'new $JSObject()');
+
+final AbstractFunctionType = JS('', '''
+  class AbstractFunctionType extends $TypeRep {
+    constructor() {
+      super();
+      this._stringValue = null;
+    }
+
+    toString() { return this.name; }
+
+    get name() {
+      if (this._stringValue) return this._stringValue;
+
+      let buffer = '(';
+      for (let i = 0; i < this.args.length; ++i) {
+        if (i > 0) {
+          buffer += ', ';
+        }
+        buffer += $typeName(this.args[i]);
+      }
+      if (this.optionals.length > 0) {
+        if (this.args.length > 0) buffer += ', ';
+        buffer += '[';
+        for (let i = 0; i < this.optionals.length; ++i) {
+          if (i > 0) {
+            buffer += ', ';
+          }
+          buffer += $typeName(this.optionals[i]);
+        }
+        buffer += ']';
+      } else if (Object.keys(this.named).length > 0) {
+        if (this.args.length > 0) buffer += ', ';
+        buffer += '{';
+        let names = $getOwnPropertyNames(this.named).sort();
+        for (let i = 0; i < names.length; ++i) {
+          if (i > 0) {
+            buffer += ', ';
+          }
+          buffer += names[i] + ': ' + $typeName(this.named[names[i]]);
+        }
+        buffer += '}';
+      }
+
+      buffer += ') -> ' + $typeName(this.returnType);
+      this._stringValue = buffer;
+      return buffer;
+    }
+  }
+''');
+
+final FunctionType = JS('', '''
+  class FunctionType extends $AbstractFunctionType {
+    /**
+     * Construct a function type. There are two arrow constructors,
+     * distinguished by the "definite" flag.
+     *
+     * The fuzzy arrow (definite is false) treats any arguments
+     * of type dynamic as having type bottom, and will always be
+     * called with a dynamic invoke.
+     *
+     * The definite arrow (definite is true) leaves arguments unchanged.
+     *
+     * We eagerly canonize the argument types to avoid having to deal with
+     * this logic in multiple places.
+     *
+     * TODO(leafp): Figure out how to present this to the user.  How
+     * should these be printed out?
+     */
+    constructor(definite, returnType, args, optionals, named) {
+      super();
+      this.definite = definite;
+      this.returnType = returnType;
+      this.args = args;
+      this.optionals = optionals;
+      this.named = named;
+
+      // TODO(vsm): This is just parameter metadata for now.
+      this.metadata = [];
+      function process(array, metadata) {
+        var result = [];
+        for (var i = 0; i < array.length; ++i) {
+          var arg = array[i];
+          if (arg instanceof Array) {
+            metadata.push(arg.slice(1));
+            result.push(arg[0]);
+          } else {
+            metadata.push([]);
+            result.push(arg);
+          }
+        }
+        return result;
+      }
+      this.args = process(this.args, this.metadata);
+      this.optionals = process(this.optionals, this.metadata);
+      // TODO(vsm): Add named arguments.
+      this._canonize();
+    }
+    _canonize() {
+      if (this.definite) return;
+
+      function replace(a) {
+        return (a == $dynamicR) ? $bottom : a;
+      }
+
+      this.args = this.args.map(replace);
+
+      if (this.optionals.length > 0) {
+        this.optionals = this.optionals.map(replace);
+      }
+
+      if (Object.keys(this.named).length > 0) {
+        let r = {};
+        for (let name of $getOwnPropertyNames(this.named)) {
+          r[name] = replace(this.named[name]);
+        }
+        this.named = r;
+      }
+    }
+  }
+''');
+
+final Typedef = JS('', '''
+  class Typedef extends $AbstractFunctionType {
+    constructor(name, closure) {
+      super();
+      this._name = name;
+      this._closure = closure;
+      this._functionType = null;
+    }
+
+    get definite() {
+      return this._functionType.definite;
+    }
+
+    get name() {
+      return this._name;
+    }
+
+    get functionType() {
+      if (!this._functionType) {
+        this._functionType = this._closure();
+      }
+      return this._functionType;
+    }
+
+    get returnType() {
+      return this.functionType.returnType;
+    }
+
+    get args() {
+      return this.functionType.args;
+    }
+
+    get optionals() {
+      return this.functionType.optionals;
+    }
+
+    get named() {
+      return this.functionType.named;
+    }
+
+    get metadata() {
+      return this.functionType.metadata;
+    }
+  }
+''');
+
+_functionType(definite, returnType, args, extra) => JS('', '''(() => {
+  // TODO(vsm): Cache / memomize?
+  let optionals;
+  let named;
+  if ($extra === void 0) {
+    optionals = [];
+    named = {};
+  } else if ($extra instanceof Array) {
+    optionals = $extra;
+    named = {};
+  } else {
+    optionals = [];
+    named = $extra;
+  }
+  return new $FunctionType($definite, $returnType, $args, optionals, named);
+})()''');
+
+///
+/// Create a "fuzzy" function type.  If any arguments are dynamic
+/// they will be replaced with bottom.
+///
+functionType(returnType, args, extra) => JS('', '''(() => {
+  return _functionType(false, $returnType, $args, $extra);
+})()''');
+
+///
+/// Create a definite function type. No substitution of dynamic for
+/// bottom occurs.
+///
+definiteFunctionType(returnType, args, extra) => JS('', '''(() => {
+  return _functionType(true, $returnType, $args, $extra);
+})()''');
+
+typedef(name, closure) => JS('', '''(() => {
+  return new $Typedef($name, $closure);
+})()''');
+
+isDartType(type) => JS('', '''(() => {
+  return $read($type) === $Type;
+})()''');
+
+typeName(type) => JS('', '''(() => {
+  // Non-instance types
+  if ($type instanceof $TypeRep) return $type.toString();
+  // Instance types
+  let tag = $read($type);
+  if (tag === $Type) {
+    let name = $type.name;
+    let args = $getGenericArgs($type);
+    if (args) {
+      name += '<';
+      for (let i = 0; i < args.length; ++i) {
+        if (i > 0) name += ', ';
+        name += $typeName(args[i]);
+      }
+      name += '>';
+    }
+    return name;
+  }
+  if (tag) return "Not a type: " + tag.name;
+  return "JSObject<" + $type.name + ">";
+})()''');
+
+isFunctionType(type) => JS('', '''(() => {
+  return $type instanceof $AbstractFunctionType || $type == $Function;
+})()''');
+
+isFunctionSubType(ft1, ft2) => JS('', '''(() => {
+  if ($ft2 == $Function) {
+    return true;
+  }
+
+  let ret1 = $ft1.returnType;
+  let ret2 = $ft2.returnType;
+
+  if (!$isSubtype_(ret1, ret2)) {
+    // Covariant return types
+    // Note, void (which can only appear as a return type) is effectively
+    // treated as dynamic.  If the base return type is void, we allow any
+    // subtype return type.
+    // E.g., we allow:
+    //   () -> int <: () -> void
+    if (ret2 != $voidR) {
+      return false;
+    }
+  }
+
+  let args1 = $ft1.args;
+  let args2 = $ft2.args;
+
+  if (args1.length > args2.length) {
+    return false;
+  }
+
+  for (let i = 0; i < args1.length; ++i) {
+    if (!$isSubtype_(args2[i], args1[i])) {
+      return false;
+    }
+  }
+
+  let optionals1 = $ft1.optionals;
+  let optionals2 = $ft2.optionals;
+
+  if (args1.length + optionals1.length < args2.length + optionals2.length) {
+    return false;
+  }
+
+  let j = 0;
+  for (let i = args1.length; i < args2.length; ++i, ++j) {
+    if (!$isSubtype_(args2[i], optionals1[j])) {
+      return false;
+    }
+  }
+
+  for (let i = 0; i < optionals2.length; ++i, ++j) {
+    if (!$isSubtype_(optionals2[i], optionals1[j])) {
+      return false;
+    }
+  }
+
+  let named1 = $ft1.named;
+  let named2 = $ft2.named;
+
+  let names = $getOwnPropertyNames(named2);
+  for (let i = 0; i < names.length; ++i) {
+    let name = names[i];
+    let n1 = named1[name];
+    let n2 = named2[name];
+    if (n1 === void 0) {
+      return false;
+    }
+    if (!$isSubtype_(n2, n1)) {
+      return false;
+    }
+  }
+
+  return true;
+})()''');
+
+///
+/// Computes the canonical type.
+/// This maps JS types onto their corresponding Dart Type.
+///
+// TODO(jmesserly): lots more needs to be done here.
+canonicalType(t) => JS('', '''(() => {
+  if ($t === Object) return $Object;
+  if ($t === Function) return $Function;
+  if ($t === Array) return $List;
+
+  // We shouldn't normally get here with these types, unless something strange
+  // happens like subclassing Number in JS and passing it to Dart.
+  if ($t === String) return $String;
+  if ($t === Number) return $double;
+  if ($t === Boolean) return $bool;
+  return $t;
+})()''');
+
+final subtypeMap = JS('', 'new Map()');
+isSubtype(t1, t2) => JS('', '''(() => {
+  // See if we already know the answer
+  // TODO(jmesserly): general purpose memoize function?
+  let map = $subtypeMap.get($t1);
+  let result;
+  if (map) {
+    result = map.get($t2);
+    if (result !== void 0) return result;
+  } else {
+    $subtypeMap.set($t1, map = new Map());
+  }
+  result = $isSubtype_($t1, $t2);
+  map.set($t2, result);
+  return result;
+})()''');
+
+_isBottom(type) => JS('', '''(() => {
+  return $type == $bottom;
+})()''');
+
+_isTop(type) => JS('', '''(() => {
+  return $type == $Object || ($type == $dynamicR);
+})()''');
+
+isSubtype_(t1, t2) => JS('', '''(() => {
+  $t1 = $canonicalType($t1);
+  $t2 = $canonicalType($t2);
+  if ($t1 == $t2) return true;
+
+  // Trivially true.
+  if ($_isTop($t2) || $_isBottom($t1)) {
+    return true;
+  }
+
+  // Trivially false.
+  if ($_isTop($t1) || $_isBottom($t2)) {
+    return false;
+  }
+
+  // "Traditional" name-based subtype check.
+  if ($isClassSubType($t1, $t2)) {
+    return true;
+  }
+
+  // Function subtyping.
+  // TODO(vsm): Handle Objects with call methods.  Those are functions
+  // even if they do not *nominally* subtype core.Function.
+  if ($isFunctionType($t1) &&
+      $isFunctionType($t2)) {
+    return $isFunctionSubType($t1, $t2);
+  }
+  return false;
+})()''');
+
+isClassSubType(t1, t2) => JS('', '''(() => {
+  // We support Dart's covariant generics with the caveat that we do not
+  // substitute bottom for dynamic in subtyping rules.
+  // I.e., given T1, ..., Tn where at least one Ti != dynamic we disallow:
+  // - S !<: S<T1, ..., Tn>
+  // - S<dynamic, ..., dynamic> !<: S<T1, ..., Tn>
+  $t1 = $canonicalType($t1);
+  $assert_($t2 == $canonicalType($t2));
+  if ($t1 == $t2) return true;
+
+  if ($t1 == $Object) return false;
+
+  // If t1 is a JS Object, we may not hit core.Object.
+  if ($t1 == null) return $t2 == $Object || $t2 == $dynamicR;
+
+  // Check if t1 and t2 have the same raw type.  If so, check covariance on
+  // type parameters.
+  let raw1 = $getGenericClass($t1);
+  let raw2 = $getGenericClass($t2);
+  if (raw1 != null && raw1 == raw2) {
+    let typeArguments1 = $getGenericArgs($t1);
+    let typeArguments2 = $getGenericArgs($t2);
+    let length = typeArguments1.length;
+    if (typeArguments2.length == 0) {
+      // t2 is the raw form of t1
+      return true;
+    } else if (length == 0) {
+      // t1 is raw, but t2 is not
+      return false;
+    }
+    $assert_(length == typeArguments2.length);
+    for (let i = 0; i < length; ++i) {
+      if (!$isSubtype(typeArguments1[i], typeArguments2[i])) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  // Check superclass.
+  if ($isClassSubType($t1.__proto__, $t2)) return true;
+
+  // Check mixins.
+  let mixins = $getMixins($t1);
+  if (mixins) {
+    for (let m1 of mixins) {
+      // TODO(jmesserly): remove the != null check once we can load core libs.
+      if (m1 != null && $isClassSubType(m1, $t2)) return true;
+    }
+  }
+
+  // Check interfaces.
+  let getInterfaces = $getImplements($t1);
+  if (getInterfaces) {
+    for (let i1 of getInterfaces()) {
+      // TODO(jmesserly): remove the != null check once we can load core libs.
+      if (i1 != null && $isClassSubType(i1, $t2)) return true;
+    }
+  }
+
+  return false;
+})()''');
+
+// TODO(jmesserly): this isn't currently used, but it could be if we want
+// `obj is NonGroundType<T,S>` to be rejected at runtime instead of compile
+// time.
+isGroundType(type) => JS('', '''(() => {
+  // TODO(vsm): Cache this if we start using it at runtime.
+
+  if ($type instanceof $AbstractFunctionType) {
+    if (!$_isTop($type.returnType)) return false;
+    for (let i = 0; i < $type.args.length; ++i) {
+      if (!$_isBottom($type.args[i])) return false;
+    }
+    for (let i = 0; i < $type.optionals.length; ++i) {
+      if (!$_isBottom($type.optionals[i])) return false;
+    }
+    let names = $getOwnPropertyNames($type.named);
+    for (let i = 0; i < names.length; ++i) {
+      if (!$_isBottom($type.named[names[i]])) return false;
+    }
+    return true;
+  }
+
+  let typeArgs = $getGenericArgs($type);
+  if (!typeArgs) return true;
+  for (let t of typeArgs) {
+    if (t != $Object && t != $dynamicR) return false;
+  }
+  return true;
+})()''');