Refactor isolate startup code in preparation for making isolate spawning more truly non-blocking.

runtime/vm/port.cc

 // Copyright (c) 2012, 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.
 
 #include "vm/port.h"
 
 #include "platform/utils.h"
 #include "vm/dart_api_impl.h"
 #include "vm/isolate.h"
 #include "vm/lockers.h"
@@ skipping 45 matching lines @@
       new_ports[new_index] = entry;
     }
   }
   delete[] map_;
   map_ = new_ports;
   capacity_ = new_capacity;
   deleted_ = 0;
 }
 
 
+const char* PortMap::PortStateString(PortState kind) {
+  switch (kind) {
+    case kNewPort:
+      return "new";
+    case kLivePort:
+      return "live";
+    case kControlPort:
+      return "control";
+    default:
+      UNREACHABLE();
+      return "UNKNOWN";
+  }
+}
+
+
 Dart_Port PortMap::AllocatePort() {
   const Dart_Port kMASK = 0x3fffffff;
   Dart_Port result = prng_->NextUInt32() & kMASK;
 
   // Keep getting new values while we have an illegal port number or the port
   // number is already in use.
   while ((result == 0) || (FindPort(result) >= 0)) {
     result = prng_->NextUInt32() & kMASK;
   }
 
   ASSERT(result != 0);
   ASSERT(FindPort(result) < 0);
   return result;
 }
 
 
-void PortMap::SetLive(Dart_Port port) {
+void PortMap::SetPortState(Dart_Port port, PortState state) {
   MutexLocker ml(mutex_);
   intptr_t index = FindPort(port);
   ASSERT(index >= 0);
-  map_[index].live = true;
-  map_[index].handler->increment_live_ports();
+  PortState old_state = map_[index].state;
+  ASSERT(old_state == kNewPort);
+  map_[index].state = state;
+  if (state == kLivePort) {
+    map_[index].handler->increment_live_ports();
+  }
   if (FLAG_trace_isolates) {
-    OS::Print("[^] Live port: \n"
+    OS::Print("[^] Port (%s) -> (%s): \n"
               "\thandler:    %s\n"
               "\tport:       %" Pd64 "\n",
+              PortStateString(old_state), PortStateString(state),
               map_[index].handler->name(), port);
   }
 }
 
 
 void PortMap::MaintainInvariants() {
   intptr_t empty = capacity_ - used_ - deleted_;
   if (used_ > ((capacity_ / 4) * 3)) {
     // Grow the port map.
     Rehash(capacity_ * 2);
   } else if (empty < deleted_) {
     // Rehash without growing the table to flush the deleted slots out of the
     // map.
     Rehash(capacity_);
   }
 }
 
 
 Dart_Port PortMap::CreatePort(MessageHandler* handler) {
   ASSERT(handler != NULL);
   MutexLocker ml(mutex_);
 #if defined(DEBUG)
   handler->CheckAccess();
 #endif
 
   Entry entry;
   entry.port = AllocatePort();
   entry.handler = handler;
-  entry.live = false;
+  entry.state = kNewPort;
 
   // Search for the first unused slot. Make use of the knowledge that here is
   // currently no port with this id in the port map.
   ASSERT(FindPort(entry.port) < 0);
   intptr_t index = entry.port % capacity_;
   Entry cur = map_[index];
   // Stop the search at the first found unused (free or deleted) slot.
   while (cur.port != 0) {
     index = (index + 1) % capacity_;
     cur = map_[index];
@@ skipping 41 matching lines @@
 
     handler = map_[index].handler;
 #if defined(DEBUG)
     handler->CheckAccess();
 #endif
     // Before releasing the lock mark the slot in the map as deleted. This makes
     // it possible to release the port map lock before flushing all of its
     // pending messages below.
     map_[index].port = 0;
     map_[index].handler = deleted_entry_;
-    if (map_[index].live) {
+    if (map_[index].state == kLivePort) {
       handler->decrement_live_ports();
     }
 
     used_--;
     deleted_++;
     MaintainInvariants();
   }
   handler->ClosePort(port);
   if (!handler->HasLivePorts() && handler->OwnedByPortMap()) {
     delete handler;
   }
   return true;
 }
 
 
 void PortMap::ClosePorts(MessageHandler* handler) {
   {
     MutexLocker ml(mutex_);
     for (intptr_t i = 0; i < capacity_; i++) {
       if (map_[i].handler == handler) {
         // Mark the slot as deleted.
         map_[i].port = 0;
         map_[i].handler = deleted_entry_;
-        if (map_[i].live) {
+        if (map_[i].state == kLivePort) {
           handler->decrement_live_ports();
         }
         used_--;
         deleted_++;
       }
     }
     MaintainInvariants();
   }
   handler->CloseAllPorts();
 }
@@ skipping 50 matching lines @@
   // TODO(iposva): Verify whether we want to keep exponentially growing.
   ASSERT(Utils::IsPowerOfTwo(kInitialCapacity));
   map_ = new Entry[kInitialCapacity];
   memset(map_, 0, kInitialCapacity * sizeof(Entry));
   capacity_ = kInitialCapacity;
   used_ = 0;
   deleted_ = 0;
 }
 
 }  // namespace dart