From ad41c28a618c7e5315898cad54e0ab0769b5db78 Mon Sep 17 00:00:00 2001
From: legendecas <legendecas@gmail.com>
Date: Tue, 26 Apr 2022 00:21:19 +0800
Subject: [PATCH] src: add initial shadow realm support

Add initial shadow realm support behind an off-by-default flag
`--experimental-shadow-realm`.
---
 .eslintrc.js                       |  1 +
 doc/api/cli.md                     | 10 ++++++++++
 lib/.eslintrc.yaml                 |  4 ++++
 node.gyp                           |  1 +
 src/api/environment.cc             |  7 +++++++
 src/node_options.cc                |  9 +++++++++
 src/node_options.h                 |  1 +
 src/node_shadow_realm.cc           | 16 ++++++++++++++++
 src/node_shadow_realm.h            | 19 +++++++++++++++++++
 test/parallel/test-shadow-realm.js | 12 ++++++++++++
 10 files changed, 80 insertions(+)
 create mode 100644 src/node_shadow_realm.cc
 create mode 100644 src/node_shadow_realm.h
 create mode 100644 test/parallel/test-shadow-realm.js

diff --git a/.eslintrc.js b/.eslintrc.js
index ea69a2893ff188..167107a0018e08 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -337,6 +337,7 @@ module.exports = {
     TextEncoderStream: 'readable',
     TransformStream: 'readable',
     TransformStreamDefaultController: 'readable',
+    ShadowRealm: 'readable',
     SubtleCrypto: 'readable',
     WritableStream: 'readable',
     WritableStreamDefaultWriter: 'readable',
diff --git a/doc/api/cli.md b/doc/api/cli.md
index 3db570deb695bc..b0ec9ffc53984b 100644
--- a/doc/api/cli.md
+++ b/doc/api/cli.md
@@ -346,6 +346,14 @@ added: v16.6.0
 
 Use this flag to disable top-level await in REPL.
 
+### `--experimental-shadow-realm`
+
+<!-- YAML
+added: REPLACEME
+ -->
+
+Use this flag to enable [ShadowRealm][] support.
+
 ### `--experimental-specifier-resolution=mode`
 
 <!-- YAML
@@ -1618,6 +1626,7 @@ Node.js options that are allowed are:
 * `--experimental-modules`
 * `--experimental-network-imports`
 * `--experimental-policy`
+* `--experimental-shadow-realm`
 * `--experimental-specifier-resolution`
 * `--experimental-top-level-await`
 * `--experimental-vm-modules`
@@ -2013,6 +2022,7 @@ $ node --max-old-space-size=1536 index.js
 [OSSL_PROVIDER-legacy]: https://www.openssl.org/docs/man3.0/man7/OSSL_PROVIDER-legacy.html
 [REPL]: repl.md
 [ScriptCoverage]: https://chromedevtools.github.io/devtools-protocol/tot/Profiler#type-ScriptCoverage
+[ShadowRealm]: https://github.com/tc39/proposal-shadowrealm
 [Source Map]: https://sourcemaps.info/spec.html
 [Subresource Integrity]: https://developer.mozilla.org/en-US/docs/Web/Security/Subresource_Integrity
 [V8 JavaScript code coverage]: https://v8project.blogspot.com/2017/12/javascript-code-coverage.html
diff --git a/lib/.eslintrc.yaml b/lib/.eslintrc.yaml
index c1635e4cf080af..6bfc102b817cfe 100644
--- a/lib/.eslintrc.yaml
+++ b/lib/.eslintrc.yaml
@@ -87,6 +87,10 @@ rules:
       message: Use `const { Request } = require('internal/deps/undici/undici');` instead of the global.
     - name: Response
       message: Use `const { Response } = require('internal/deps/undici/undici');` instead of the global.
+      # ShadowRealm is not available in primordials because it can be
+      # disabled with --no-harmony-shadow-realm CLI flag.
+    - name: ShadowRealm
+      message: Use `const { ShadowRealm } = globalThis;` instead of the global.
       # SharedArrayBuffer is not available in primordials because it can be
       # disabled with --no-harmony-sharedarraybuffer CLI flag.
     - name: SharedArrayBuffer
diff --git a/node.gyp b/node.gyp
index 4e06d00c823290..9cee99f731464e 100644
--- a/node.gyp
+++ b/node.gyp
@@ -531,6 +531,7 @@
         'src/node_report_module.cc',
         'src/node_report_utils.cc',
         'src/node_serdes.cc',
+        'src/node_shadow_realm.cc',
         'src/node_snapshotable.cc',
         'src/node_sockaddr.cc',
         'src/node_stat_watcher.cc',
diff --git a/src/api/environment.cc b/src/api/environment.cc
index f3a8f49812d5ce..ccdcdefb20fe84 100644
--- a/src/api/environment.cc
+++ b/src/api/environment.cc
@@ -5,6 +5,7 @@
 #include "node_native_module_env.h"
 #include "node_options-inl.h"
 #include "node_platform.h"
+#include "node_shadow_realm.h"
 #include "node_v8_platform-inl.h"
 #include "node_wasm_web_api.h"
 #include "uv.h"
@@ -261,6 +262,12 @@ void SetIsolateMiscHandlers(v8::Isolate* isolate, const IsolateSettings& s) {
     isolate->SetWasmStreamingCallback(wasm_web_api::StartStreamingCompilation);
   }
 
+  if (per_process::cli_options->get_per_isolate_options()
+          ->experimental_shadow_realm) {
+    isolate->SetHostCreateShadowRealmContextCallback(
+        shadow_realm::HostCreateShadowRealmContextCallback);
+  }
+
   if ((s.flags & SHOULD_NOT_SET_PROMISE_REJECTION_CALLBACK) == 0) {
     auto* promise_reject_cb = s.promise_reject_callback ?
       s.promise_reject_callback : PromiseRejectCallback;
diff --git a/src/node_options.cc b/src/node_options.cc
index b2b4c2c18c7f9f..4ef017abebb9be 100644
--- a/src/node_options.cc
+++ b/src/node_options.cc
@@ -713,6 +713,15 @@ PerIsolateOptionsParser::PerIsolateOptionsParser(
   Implies("--harmony-top-level-await", "--experimental-top-level-await");
   ImpliesNot("--no-harmony-top-level-await", "--experimental-top-level-await");
 
+  AddOption("--experimental-shadow-realm",
+            "",
+            &PerIsolateOptions::experimental_shadow_realm,
+            kAllowedInEnvironment);
+  AddOption("--harmony-shadow-realm", "", V8Option{});
+  Implies("--experimental-shadow-realm", "--harmony-shadow-realm");
+  Implies("--harmony-shadow-realm", "--experimental-shadow-realm");
+  ImpliesNot("--no-harmony-shadow-realm", "--experimental-shadow-realm");
+
   Insert(eop, &PerIsolateOptions::get_per_env_options);
 }
 
diff --git a/src/node_options.h b/src/node_options.h
index 0757a767a16208..a6f81d27d5a06d 100644
--- a/src/node_options.h
+++ b/src/node_options.h
@@ -207,6 +207,7 @@ class PerIsolateOptions : public Options {
   bool report_uncaught_exception = false;
   bool report_on_signal = false;
   bool experimental_top_level_await = true;
+  bool experimental_shadow_realm = false;
   std::string report_signal = "SIGUSR2";
   inline EnvironmentOptions* get_per_env_options();
   void CheckOptions(std::vector<std::string>* errors) override;
diff --git a/src/node_shadow_realm.cc b/src/node_shadow_realm.cc
new file mode 100644
index 00000000000000..2ccd62edc315d7
--- /dev/null
+++ b/src/node_shadow_realm.cc
@@ -0,0 +1,16 @@
+#include "node_shadow_realm.h"
+
+namespace node {
+namespace shadow_realm {
+using v8::Context;
+using v8::Local;
+using v8::MaybeLocal;
+
+// static
+MaybeLocal<Context> HostCreateShadowRealmContextCallback(
+    Local<Context> initiator_context) {
+  return Context::New(initiator_context->GetIsolate());
+}
+
+}  // namespace shadow_realm
+}  // namespace node
diff --git a/src/node_shadow_realm.h b/src/node_shadow_realm.h
new file mode 100644
index 00000000000000..a10fc425661f56
--- /dev/null
+++ b/src/node_shadow_realm.h
@@ -0,0 +1,19 @@
+#ifndef SRC_NODE_SHADOW_REALM_H_
+#define SRC_NODE_SHADOW_REALM_H_
+
+#if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
+
+#include "v8.h"
+
+namespace node {
+namespace shadow_realm {
+
+v8::MaybeLocal<v8::Context> HostCreateShadowRealmContextCallback(
+    v8::Local<v8::Context> initiator_context);
+
+}  // namespace shadow_realm
+}  // namespace node
+
+#endif  // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
+
+#endif  // SRC_NODE_SHADOW_REALM_H_
diff --git a/test/parallel/test-shadow-realm.js b/test/parallel/test-shadow-realm.js
new file mode 100644
index 00000000000000..0b20265537fb5c
--- /dev/null
+++ b/test/parallel/test-shadow-realm.js
@@ -0,0 +1,12 @@
+// Flags: --experimental-shadow-realm
+'use strict';
+
+require('../common');
+const assert = require('assert');
+
+// Validates we can construct ShadowRealm successfully.
+const shadowRealm = new ShadowRealm();
+
+const getter = shadowRealm.evaluate('globalThis.realmValue = "inner"; () => globalThis.realmValue;');
+assert.strictEqual(getter(), 'inner');
+assert.strictEqual('realmValue' in globalThis, false);