refactor: introduce primordials (#10939)

This commit introduces primordials to deno_core. Primordials are a
frozen set of all intrinsic objects in the runtime. They are not
vulnerable to prototype pollution.

1 files changed, 190 insertions, 0 deletions

diff --git a/core/01_core.js b/core/01_core.js
new file mode 100644
index 000000000..74e00b5df
--- /dev/null
+++ b/core/01_core.js
@@ -0,0 +1,190 @@
+// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
+"use strict";
+
+((window) => {
+  const {
+    Error,
+    RangeError,
+    ReferenceError,
+    SyntaxError,
+    TypeError,
+    URIError,
+    Map,
+    Array,
+    ArrayPrototypeFill,
+    Promise,
+    ObjectFreeze,
+    ObjectFromEntries,
+    MapPrototypeGet,
+    MapPrototypeDelete,
+    MapPrototypeSet,
+    PromisePrototypeThen,
+    ObjectAssign,
+  } = window.__bootstrap.primordials;
+
+  // Available on start due to bindings.
+  const { opcall } = window.Deno.core;
+
+  let opsCache = {};
+  const errorMap = {};
+  // Builtin v8 / JS errors
+  registerErrorClass("Error", Error);
+  registerErrorClass("RangeError", RangeError);
+  registerErrorClass("ReferenceError", ReferenceError);
+  registerErrorClass("SyntaxError", SyntaxError);
+  registerErrorClass("TypeError", TypeError);
+  registerErrorClass("URIError", URIError);
+
+  let nextPromiseId = 1;
+  const promiseMap = new Map();
+  const RING_SIZE = 4 * 1024;
+  const NO_PROMISE = null; // Alias to null is faster than plain nulls
+  const promiseRing = ArrayPrototypeFill(new Array(RING_SIZE), NO_PROMISE);
+
+  function setPromise(promiseId) {
+    const idx = promiseId % RING_SIZE;
+    // Move old promise from ring to map
+    const oldPromise = promiseRing[idx];
+    if (oldPromise !== NO_PROMISE) {
+      const oldPromiseId = promiseId - RING_SIZE;
+      MapPrototypeSet(promiseMap, oldPromiseId, oldPromise);
+    }
+    // Set new promise
+    return promiseRing[idx] = newPromise();
+  }
+
+  function getPromise(promiseId) {
+    // Check if out of ring bounds, fallback to map
+    const outOfBounds = promiseId < nextPromiseId - RING_SIZE;
+    if (outOfBounds) {
+      const promise = MapPrototypeGet(promiseMap, promiseId);
+      MapPrototypeDelete(promiseMap, promiseId);
+      return promise;
+    }
+    // Otherwise take from ring
+    const idx = promiseId % RING_SIZE;
+    const promise = promiseRing[idx];
+    promiseRing[idx] = NO_PROMISE;
+    return promise;
+  }
+
+  function newPromise() {
+    let resolve, reject;
+    const promise = new Promise((resolve_, reject_) => {
+      resolve = resolve_;
+      reject = reject_;
+    });
+    promise.resolve = resolve;
+    promise.reject = reject;
+    return promise;
+  }
+
+  function ops() {
+    return opsCache;
+  }
+
+  function syncOpsCache() {
+    // op id 0 is a special value to retrieve the map of registered ops.
+    opsCache = ObjectFreeze(ObjectFromEntries(opcall(0)));
+  }
+
+  function handleAsyncMsgFromRust() {
+    for (let i = 0; i < arguments.length; i += 2) {
+      const promiseId = arguments[i];
+      const res = arguments[i + 1];
+      const promise = getPromise(promiseId);
+      promise.resolve(res);
+    }
+  }
+
+  function dispatch(opName, promiseId, control, zeroCopy) {
+    const opId = typeof opName === "string" ? opsCache[opName] : opName;
+    return opcall(opId, promiseId, control, zeroCopy);
+  }
+
+  function registerErrorClass(className, errorClass) {
+    registerErrorBuilder(className, (msg) => new errorClass(msg));
+  }
+
+  function registerErrorBuilder(className, errorBuilder) {
+    if (typeof errorMap[className] !== "undefined") {
+      throw new TypeError(`Error class for "${className}" already registered`);
+    }
+    errorMap[className] = errorBuilder;
+  }
+
+  function unwrapOpResult(res) {
+    // .$err_class_name is a special key that should only exist on errors
+    if (res?.$err_class_name) {
+      const className = res.$err_class_name;
+      const errorBuilder = errorMap[className];
+      if (!errorBuilder) {
+        throw new Error(
+          `Unregistered error class: "${className}"\n  ${res.message}\n  Classes of errors returned from ops should be registered via Deno.core.registerErrorClass().`,
+        );
+      }
+      throw errorBuilder(res.message);
+    }
+    return res;
+  }
+
+  function opAsync(opName, arg1 = null, arg2 = null) {
+    const promiseId = nextPromiseId++;
+    const maybeError = dispatch(opName, promiseId, arg1, arg2);
+    // Handle sync error (e.g: error parsing args)
+    if (maybeError) return unwrapOpResult(maybeError);
+    return PromisePrototypeThen(setPromise(promiseId), unwrapOpResult);
+  }
+
+  function opSync(opName, arg1 = null, arg2 = null) {
+    return unwrapOpResult(dispatch(opName, null, arg1, arg2));
+  }
+
+  function resources() {
+    return ObjectFromEntries(opSync("op_resources"));
+  }
+
+  function close(rid) {
+    opSync("op_close", rid);
+  }
+
+  function print(str, isErr = false) {
+    opSync("op_print", str, isErr);
+  }
+
+  // Some "extensions" rely on "BadResource" and "Interrupted" errors in the
+  // JS code (eg. "deno_net") so they are provided in "Deno.core" but later
+  // reexported on "Deno.errors"
+  class BadResource extends Error {
+    constructor(msg) {
+      super(msg);
+      this.name = "BadResource";
+    }
+  }
+
+  class Interrupted extends Error {
+    constructor(msg) {
+      super(msg);
+      this.name = "Interrupted";
+    }
+  }
+
+  // Extra Deno.core.* exports
+  const core = ObjectAssign(globalThis.Deno.core, {
+    opAsync,
+    opSync,
+    ops,
+    close,
+    print,
+    resources,
+    registerErrorBuilder,
+    registerErrorClass,
+    handleAsyncMsgFromRust,
+    syncOpsCache,
+    BadResource,
+    Interrupted,
+  });
+
+  ObjectAssign(globalThis.__bootstrap, { core });
+  ObjectAssign(globalThis.Deno, { core });
+})(globalThis);