Refactor runtime into libraries, better type reps

lib/runtime/_operations.js

+// 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 runtime operations on objects used by the code
+ * generator.
+ */
+dart_library.library('dart_runtime/_operations', null, /* Imports */[
+], /* Lazy Imports */[
+  'dart/async',
+  'dart/core',
+  'dart_runtime/_classes',
+  'dart_runtime/_errors',
+  'dart_runtime/_rtti',
+  'dart_runtime/_types'
+], function(exports, async, core, classes, errors, rtti, types) {
+  'use strict';
+
+  const getOwnNamesAndSymbols = dart_utils.getOwnNamesAndSymbols;
+  const throwError = dart_utils.throwError;
+
+  const getOwnPropertyNames = Object.getOwnPropertyNames;
+  const hasOwnProperty = Object.prototype.hasOwnProperty;
+
+  const slice = [].slice;
+
+  function _canonicalFieldName(obj, name, args, displayName) {
+    name = classes.canonicalMember(obj, name)
+    if (name) return name;
+    // TODO(jmesserly): in the future we might have types that "overlay" Dart
+    // methods while also exposing the full native API, e.g. dart:html vs
+    // dart:dom. To support that we'd need to fall back to the normal name
+    // if an extension method wasn't found.
+    errors.throwNoSuchMethod(obj, displayName, args);
+  }
+
+  function dload(obj, field) {
+    field = _canonicalFieldName(obj, field, [], field);
+    if (classes.hasMethod(obj, field)) {
+      return classes.bind(obj, field);
+    }
+    // TODO(vsm): Implement NSM robustly.  An 'in' check breaks on certain
+    // types.  hasOwnProperty doesn't chase the proto chain.
+    // Also, do we want an NSM on regular JS objects?
+    // See: https://github.com/dart-lang/dev_compiler/issues/169
+    let result = obj[field];
+
+    // TODO(vsm): Check this more robustly.
+    if (typeof result == "function" && !hasOwnProperty.call(obj, field)) {
+      // This appears to be a method tearoff.  Bind this.
+      return result.bind(obj);
+    }
+        return result;
+  }
+  exports.dload = dload;
+
+  function dput(obj, field, value) {
+    field = _canonicalFieldName(obj, field, [value], field);
+    // TODO(vsm): Implement NSM and type checks.
+    // See: https://github.com/dart-lang/dev_compiler/issues/170
+    obj[field] = value;
+  }
+  exports.dput = dput;
+
+
+  /// Check that a function of a given type can be applied to
+  /// actuals.
+  function checkApply(type, actuals) {
+    if (actuals.length < type.args.length) return false;
+    let index = 0;
+    for(let i = 0; i < type.args.length; ++i) {
+      if (!instanceOfOrNull(actuals[i], type.args[i])) return false;
+      ++index;
+    }
+    if (actuals.length == type.args.length) return true;
+    let extras = actuals.length - type.args.length;
+    if (type.optionals.length > 0) {
+      if (extras > type.optionals.length) return false;
+      for(let i = 0, j=index; i < extras; ++i, ++j) {
+        if (!instanceOfOrNull(actuals[j], type.optionals[i])) return false;
+      }
+      return true;
+    }
+    // TODO(leafp): We can't tell when someone might be calling
+    // something expecting an optional argument with named arguments
+
+    if (extras != 1) return false;
+    // An empty named list means no named arguments
+    if (getOwnPropertyNames(type.named).length == 0) return false;
+    let opts = actuals[index];
+    let names = getOwnPropertyNames(opts);
+    // Type is something other than a map
+    if (names.length == 0) return false;
+    for (name of names) {
+      if (!(hasOwnProperty.call(type.named, name))) {
+        return false;
+      }
+      if (!instanceOfOrNull(opts[name], type.named[name])) return false;
+    }
+    return true;
+  }
+
+  function throwNoSuchMethod(obj, name, args, opt_func) {
+    if (obj === void 0) obj = opt_func;
+    errors.throwNoSuchMethod(obj, name, args);
+  }
+
+  function checkAndCall(f, ftype, obj, args, name) {
+    if (!(f instanceof Function)) {
+      // We're not a function (and hence not a method either)
+      // Grab the `call` method if it's not a function.
+      if (f !== null) {
+        ftype = classes.getMethodType(f, 'call');
+        f = f.call;
+      }
+      if (!(f instanceof Function)) {
+        throwNoSuchMethod(obj, name, args);
+      }
+    }
+    // If f is a function, but not a method (no method type)
+    // then it should have been a function valued field, so
+    // get the type from the function.
+    if (ftype === void 0) {
+      ftype = rtti.read(f);
+    }
+
+    if (!ftype) {
+      // TODO(leafp): Allow JS objects to go through?
+      // This includes the DOM.
+      return f.apply(obj, args);
+    }
+
+    if (checkApply(ftype, args)) {
+      return f.apply(obj, args);
+    }
+
+    // TODO(leafp): throw a type error (rather than NSM)
+    // if the arity matches but the types are wrong.
+    throwNoSuchMethod(obj, name, args, f);
+  }
+
+  function dcall(f/*, ...args*/) {
+    let args = slice.call(arguments, 1);
+    let ftype = rtti.read(f);
+    return checkAndCall(f, ftype, void 0, args, 'call');
+  }
+  exports.dcall = dcall;
+
+
+  /** Shared code for dsend, dindex, and dsetindex. */
+  function callMethod(obj, name, args, displayName) {
+    let symbol = _canonicalFieldName(obj, name, args, displayName);
+    let f = obj[symbol];
+    let ftype = classes.getMethodType(obj, name);
+    return checkAndCall(f, ftype, obj, args, displayName);
+  }
+
+  function dsend(obj, method/*, ...args*/) {
+    return callMethod(obj, method, slice.call(arguments, 2));
+  }
+  exports.dsend = dsend;
+
+  function dindex(obj, index) {
+    return callMethod(obj, 'get', [index], '[]');
+  }
+  exports.dindex = dindex;
+
+  function dsetindex(obj, index, value) {
+    return callMethod(obj, 'set', [index, value], '[]=');
+  }
+  exports.dsetindex = dsetindex;
+
+  function _ignoreTypeFailure(actual, type) {
+    // TODO(vsm): Remove this hack ...
+    // This is primarily due to the lack of generic methods,
+    // but we need to triage all the errors.
+    let isSubtype = types.isSubtype;
+    if (isSubtype(type, core.Iterable) && isSubtype(actual, core.Iterable) ||
+        isSubtype(type, async.Future) && isSubtype(actual, async.Future) ||
+        isSubtype(type, core.Map) && isSubtype(actual, core.Map) ||
+        isSubtype(type, core.Function) && isSubtype(actual, core.Function)) {
+      console.error('Ignoring cast fail from ' + types.typeName(actual) +
+        ' to ' + types.typeName(type));
+      return true;
+    }
+    return false;
+  }
+
+  function instanceOf(obj, type) {
+    return types.isSubtype(rtti.realRuntimeType(obj), type);
+  }
+  exports.instanceOf = instanceOf;
+
+  function instanceOfOrNull(obj, type) {
+    if ((obj == null) || instanceOf(obj, type)) return true;
+    let actual = rtti.realRuntimeType(obj);
+    if (_ignoreTypeFailure(actual, type)) return true;
+    return false;
+  }
+  exports.instanceOfOrNull = instanceOfOrNull;
+
+  function cast(obj, type) {
+    // TODO(vsm): handle non-nullable types
+    if (obj == null) return obj;
+    let actual = rtti.realRuntimeType(obj);
+    if (types.isSubtype(actual, type)) return obj;
+    if (_ignoreTypeFailure(actual, type)) return obj;
+    errors.throwCastError(actual, type);
+  }
+  exports.cast = cast;
+
+  function arity(f) {
+    // TODO(jmesserly): need to parse optional params.
+    // In ES6, length is the number of required arguments.
+    return { min: f.length, max: f.length };
+  }
+  exports.arity = arity;
+
+  function equals(x, y) {
+    if (x == null || y == null) return x == y;
+    let eq = x['=='];
+    return eq ? eq.call(x, y) : x === y;
+  }
+  exports.equals = equals;
+
+  /** Checks that `x` is not null or undefined. */
+  function notNull(x) {
+    // TODO(leafp): This is probably not the right error to throw.
+    if (x == null) throwError('expected not-null value');
+    return x;
+  }
+  exports.notNull = notNull;
+
+  /**
+   * Creates a dart:collection LinkedHashMap.
+   *
+   * For a map with string keys an object literal can be used, for example
+   * `map({'hi': 1, 'there': 2})`.
+   *
+   * Otherwise an array should be used, for example `map([1, 2, 3, 4])` will
+   * create a map with keys [1, 3] and values [2, 4]. Each key-value pair
+   * should be adjacent entries in the array.
+   *
+   * For a map with no keys the function can be called with no arguments, for
+   * example `map()`.
+   */
+  // TODO(jmesserly): this could be faster
+  function map(values) {
+    let map = collection.LinkedHashMap.new();
+    if (Array.isArray(values)) {
+      for (let i = 0, end = values.length - 1; i < end; i += 2) {
+        let key = values[i];
+        let value = values[i + 1];
+        map.set(key, value);
+      }
+    } else if (typeof values === 'object') {
+      for (let key of getOwnPropertyNames(values)) {
+        map.set(key, values[key]);
+      }
+    }
+    return map;
+  }
+  exports.map = map;
+
+  function assert(condition) {
+    if (!condition) errors.throwAssertionError();
+  }
+  exports.assert = assert;
+
+  function throw_(obj) { throw obj; }
+  exports.throw_ = throw_;
+
+
+  function stackTrace(exception) {
+    return _js_helper.getTraceFromException(exception);
+  }
+  exports.stackTrace = stackTrace;
+
+  let _value = Symbol('_value');
+  /**
+   * Looks up a sequence of [keys] in [map], recursively, and
+   * returns the result. If the value is not found, [valueFn] will be called to
+   * add it. For example:
+   *
+   *     let map = new Map();
+   *     putIfAbsent(map, [1, 2, 'hi ', 'there '], () => 'world');
+   *
+   * ... will create a Map with a structure like:
+   *
+   *     { 1: { 2: { 'hi ': { 'there ': 'world' } } } }
+   */
+  function multiKeyPutIfAbsent(map, keys, valueFn) {
+    for (let k of keys) {
+      let value = map.get(k);
+      if (!value) {
+        // TODO(jmesserly): most of these maps are very small (e.g. 1 item),
+        // so it may be worth optimizing for that.
+        map.set(k, value = new Map());
+      }
+      map = value;
+    }
+    if (map.has(_value)) return map.get(_value);
+    let value = valueFn();
+    map.set(_value, value);
+    return value;
+  }
+
+  /** The global constant table. */
+  const constants = new Map();
+
+  /**
+   * Canonicalize a constant object.
+   *
+   * Preconditions:
+   * - `obj` is an objects or array, not a primitive.
+   * - nested values of the object are themselves already canonicalized.
+   */
+  function constant(obj) {
+    let objectKey = [rtti.realRuntimeType(obj)];
+    // TODO(jmesserly): there's no guarantee in JS that names/symbols are
+    // returned in the same order.
+    //
+    // We could probably get the same order if we're judicious about
+    // initializing fields in a consistent order across all const constructors.
+    // Alternatively we need a way to sort them to make consistent.
+    //
+    // Right now we use the (name,value) pairs in sequence, which prevents
+    // an object with incorrect field values being returned, but won't
+    // canonicalize correctly if key order is different.
+    for (let name of getOwnNamesAndSymbols(obj)) {
+      objectKey.push(name);
+      objectKey.push(obj[name]);
+    }
+    return multiKeyPutIfAbsent(constants, objectKey, () => obj);
+  }
+  exports.const = constant;
+
+
+  // The following are helpers for Object methods when the receiver
+  // may be null or primitive.  These should only be generated by
+  // the compiler.
+  function hashCode(obj) {
+    if (obj == null) {
+      return 0;
+    }
+    // TODO(vsm): What should we do for primitives and non-Dart objects?
+    switch (typeof obj) {
+    case "number":
+    case "boolean":
+      return obj & 0x1FFFFFFF;
+    case "string":
+        // TODO(vsm): Call the JSString hashCode?
+      return obj.length;
+    }
+    return obj.hashCode;
+  }
+  exports.hashCode = hashCode;
+
+  function toString(obj) {
+    if (obj == null) {
+      return "null";
+    }
+    return obj.toString();
+  }
+  exports.toString = toString;
+
+  function noSuchMethod(obj, invocation) {
+    if (obj == null) {
+      errors.throwNoSuchMethod(obj, invocation.memberName,
+        invocation.positionalArguments, invocation.namedArguments);
+    }
+    switch (typeof obj) {
+      case "number":
+      case "boolean":
+      case "string":
+        errors.throwNoSuchMethod(obj, invocation.memberName,
+          invocation.positionalArguments, invocation.namedArguments);
+    }
+    return obj.noSuchMethod(invocation);
+  }
+  exports.noSuchMethod = noSuchMethod;
+
+  class JsIterator {
+    constructor(dartIterator) {
+      this.dartIterator = dartIterator;
+    }
+    next() {
+      let i = this.dartIterator;
+      let done = !i.moveNext();
+      return { done: done, value: done ? void 0 : i.current };
+    }
+  }
+  exports.JsIterator = JsIterator;
+
+
+});