Add support for native ports in the vm.

runtime/vm/dart_api_impl.cc

Index: runtime/vm/dart_api_impl.cc
===================================================================
--- runtime/vm/dart_api_impl.cc	(revision 3603)
+++ runtime/vm/dart_api_impl.cc	(working copy)
@@ -15,8 +15,9 @@
 #include "vm/exceptions.h"
 #include "vm/growable_array.h"
 #include "vm/longjump.h"
-#include "vm/message_queue.h"
+#include "vm/message.h"
 #include "vm/native_entry.h"
+#include "vm/native_message_handler.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/port.h"
@@ -676,7 +677,7 @@
   Message::Priority priority = Message::kNormalPriority;
   do {
     DARTSCOPE(isolate);
-    message = isolate->message_queue()->DequeueNoWait();
+    message = isolate->message_handler()->queue()->DequeueNoWait();
     if (message == NULL) {
       break;
     }
@@ -705,7 +706,7 @@
 DART_EXPORT bool Dart_HasLivePorts() {
   Isolate* isolate = Isolate::Current();
   ASSERT(isolate);
-  return isolate->live_ports() > 0;
+  return isolate->message_handler()->HasLivePorts();
 }
 
 
@@ -743,6 +744,41 @@
 }
 
 
+DART_EXPORT Dart_Port Dart_NewNativePort(const char* name,
+                                         Dart_NativeMessageHandler func,
+                                         bool allow_concurrent) {
+  if (name == NULL) {
+    name = "<UnnamedNativePort>";
+  }
+  if (func == NULL) {
+      FATAL1("%s expects argument 'func' to be non-null.", CURRENT_FUNC);

[siva, 2012/01/28 00:21:05]

Why is this FATAL and not a
return Api::NewError(...);  // Expect argument to be non NULL

[turnidge, 2012/01/31 20:04:31]

We can only do Api::NewError when we are in an isolate.  I don't want to force
callers of this function to be in an isolate.

[siva, 2012/02/01 00:38:56]

Agreed but it seems odd that a bad parameter results in a fatal error. Can we
have some kind of an invalid sentinel port that can be returned on all error
cases?

On 2012/01/31 20:04:31, turnidge wrote:

[turnidge, 2012/02/01 18:51:26]

Ok.  Done.  Added a test for this too.

+  }
+  // Start the native port without a current isolate.
+  Isolate* saved = Isolate::Current();

[Søren Gjesse, 2012/01/27 13:33:14]

How about a stack allocated isolate switcher?

{
  SwitchIsolate switch(NULL);

  ...
}

The name could probably be better.

[turnidge, 2012/01/31 20:04:31]

I made an IsolateSaver class which handles the save/restore but not the switch.

On 2012/01/27 13:33:14, Søren Gjesse wrote:

+  Isolate::SetCurrent(NULL);

[siva, 2012/01/28 00:21:05]

Should we restrict creation of native ports only on threads which do not have an
isolate?

i.e change this to
ASSERT(Isolate::Current() == NULL);

[turnidge, 2012/01/31 20:04:31]

I'm not sure.  I could see us often creating the native thread on demand when it
is first needed in dart code.  It might be a pain to require them to always
Dart_ExitIsolate before they call this function.  Can we defer this decision?

On 2012/01/28 00:21:05, asiva wrote:

[siva, 2012/02/01 00:38:56]

Sure we can revisit this once we have usage patterns. Maybe a TODO here to
revisit would suffice for now.

On 2012/01/31 20:04:31, turnidge wrote:

+
+  NativeMessageHandler* handler = new NativeMessageHandler(name, func);
+  Dart_Port port_id = PortMap::CreatePort(handler);
+  handler->StartWorker();
+
+  Isolate::SetCurrent(saved);
+  return port_id;
+}
+
+
+DART_EXPORT bool Dart_CloseNativePort(Dart_Port native_port_id) {
+  // Close the native port without a current isolate.
+  Isolate* saved = Isolate::Current();
+  Isolate::SetCurrent(NULL);

[siva, 2012/01/28 00:21:05]

Ditto regarding current isolate.

[turnidge, 2012/01/31 20:04:31]

Maybe we can chat about it during the tea break.

+
+  // TODO(turnidge): Check that the port is native before trying to close.
+  bool result = PortMap::ClosePort(native_port_id);
+
+  Isolate::SetCurrent(saved);
+  return result;
+}
+
+
 DART_EXPORT Dart_Handle Dart_NewSendPort(Dart_Port port_id) {
   Isolate* isolate = Isolate::Current();
   DARTSCOPE(isolate);