runtime/vm/port.h

// Copyright (c) 2011, 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.

#ifndef RUNTIME_VM_PORT_H_
#define RUNTIME_VM_PORT_H_

#include "include/dart_api.h"
#include "vm/allocation.h"
#include "vm/globals.h"
#include "vm/json_stream.h"
#include "vm/random.h"

namespace dart {

class Isolate;
class Message;
class MessageHandler;
class Mutex;
class PortMapTestPeer;

class PortMap : public AllStatic {
 public:
  enum PortState {
    kNewPort = 0,      // a newly allocated port
    kLivePort = 1,     // a regular port (has a ReceivePort)
    kControlPort = 2,  // a special control port (has a ReceivePort)
  };

  // Allocate a port for the provided handler and return its VM-global id.
  static Dart_Port CreatePort(MessageHandler* handler);

  // Indicates that a port has had a ReceivePort created for it at the
  // dart language level.  The port remains live until it is closed.
  static void SetPortState(Dart_Port id, PortState kind);

  // Close the port with id. All pending messages will be dropped.
  //
  // Returns true if the port is successfully closed.
  static bool ClosePort(Dart_Port id);

  // Close all the ports for the provided handler.
  static void ClosePorts(MessageHandler* handler);

  // Enqueues the message in the port with id. Returns false if the port is not
  // active any longer.
  //
  // Claims ownership of 'message'.
  static bool PostMessage(Message* message);

  // Returns whether a port is local to the current isolate.
  static bool IsLocalPort(Dart_Port id);

  // Returns the owning Isolate for port 'id'.
  static Isolate* GetIsolate(Dart_Port id);

  static void Init();
  static void Cleanup();

  static void PrintPortsForMessageHandler(MessageHandler* handler,
                                          JSONStream* stream);

  static void DebugDumpForMessageHandler(MessageHandler* handler);

 private:
  friend class dart::PortMapTestPeer;

  // Mapping between port numbers and handlers.
  //
  // Free entries have id == 0 and handler == NULL. Deleted entries
  // have id == 0 and handler == deleted_entry_.
  typedef struct {
    Dart_Port port;
    MessageHandler* handler;
    PortState state;
  } Entry;

  static const char* PortStateString(PortState state);

  // Allocate a new unique port.
  static Dart_Port AllocatePort();

  static bool IsActivePort(Dart_Port id);
  static bool IsLivePort(Dart_Port id);

  static intptr_t FindPort(Dart_Port port);
  static void Rehash(intptr_t new_capacity);

  static void MaintainInvariants();

  // Lock protecting access to the port map.
  static Mutex* mutex_;

  // Hashmap of ports.
  static Entry* map_;
  static MessageHandler* deleted_entry_;
  static intptr_t capacity_;
  static intptr_t used_;
  static intptr_t deleted_;

  static Random* prng_;
};

}  // namespace dart

#endif  // RUNTIME_VM_PORT_H_