Cherry pick http://codereview.chromium.org/1207003/show

Implement support for reattaching a global object to a context. This
can be used to use the same global object for different contexts at
different points in time.

Needed to fix b: 2533219

Change-Id: Ib3b0d35f6ce3e0a5f4b8e54561ba2e99a9ab0ab1

1 files changed, 81 insertions, 2 deletions

diff --git a/test/cctest/test-api.cc b/test/cctest/test-api.cc
index db16bfc4..80bc0743 100644
--- a/test/cctest/test-api.cc
+++ b/test/cctest/test-api.cc
@@ -4350,7 +4350,7 @@ TEST(ContextDetachGlobal) {
   // Enter env2
   env2->Enter();
 
-  // Create a function in env1
+  // Create a function in env2 and add a reference to it in env1.
   Local<v8::Object> global2 = env2->Global();
   global2->Set(v8_str("prop"), v8::Integer::New(1));
   CompileRun("function getProp() {return prop;}");
@@ -4358,7 +4358,7 @@ TEST(ContextDetachGlobal) {
   env1->Global()->Set(v8_str("getProp"),
                       global2->Get(v8_str("getProp")));
 
-  // Detach env1's global, and reuse the global object of env1
+  // Detach env2's global, and reuse the global object of env2
   env2->Exit();
   env2->DetachGlobal();
   // env2 has a new global object.
@@ -4398,6 +4398,85 @@ TEST(ContextDetachGlobal) {
 }
 
 
+TEST(DetachAndReattachGlobal) {
+  v8::HandleScope scope;
+  LocalContext env1;
+
+  // Create second environment.
+  v8::Persistent<Context> env2 = Context::New();
+
+  Local<Value> foo = v8_str("foo");
+
+  // Set same security token for env1 and env2.
+  env1->SetSecurityToken(foo);
+  env2->SetSecurityToken(foo);
+
+  // Create a property on the global object in env2.
+  {
+    v8::Context::Scope scope(env2);
+    env2->Global()->Set(v8_str("p"), v8::Integer::New(42));
+  }
+
+  // Create a reference to env2 global from env1 global.
+  env1->Global()->Set(v8_str("other"), env2->Global());
+
+  // Check that we have access to other.p in env2 from env1.
+  Local<Value> result = CompileRun("other.p");
+  CHECK(result->IsInt32());
+  CHECK_EQ(42, result->Int32Value());
+
+  // Hold on to global from env2 and detach global from env2.
+  Local<v8::Object> global2 = env2->Global();
+  env2->DetachGlobal();
+
+  // Check that the global has been detached. No other.p property can
+  // be found.
+  result = CompileRun("other.p");
+  CHECK(result->IsUndefined());
+
+  // Reuse global2 for env3.
+  v8::Persistent<Context> env3 =
+      Context::New(0, v8::Handle<v8::ObjectTemplate>(), global2);
+  CHECK_EQ(global2, env3->Global());
+
+  // Start by using the same security token for env3 as for env1 and env2.
+  env3->SetSecurityToken(foo);
+
+  // Create a property on the global object in env3.
+  {
+    v8::Context::Scope scope(env3);
+    env3->Global()->Set(v8_str("p"), v8::Integer::New(24));
+  }
+
+  // Check that other.p is now the property in env3 and that we have access.
+  result = CompileRun("other.p");
+  CHECK(result->IsInt32());
+  CHECK_EQ(24, result->Int32Value());
+
+  // Change security token for env3 to something different from env1 and env2.
+  env3->SetSecurityToken(v8_str("bar"));
+
+  // Check that we do not have access to other.p in env1. |other| is now
+  // the global object for env3 which has a different security token,
+  // so access should be blocked.
+  result = CompileRun("other.p");
+  CHECK(result->IsUndefined());
+
+  // Detach the global for env3 and reattach it to env2.
+  env3->DetachGlobal();
+  env2->ReattachGlobal(global2);
+
+  // Check that we have access to other.p again in env1.  |other| is now
+  // the global object for env2 which has the same security token as env1.
+  result = CompileRun("other.p");
+  CHECK(result->IsInt32());
+  CHECK_EQ(42, result->Int32Value());
+
+  env2.Dispose();
+  env3.Dispose();
+}
+
+
 static bool NamedAccessBlocker(Local<v8::Object> global,
                                Local<Value> name,
                                v8::AccessType type,