[mojo] Ports EDK

mojo/edk/system/message_pipe_dispatcher.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_EDK_SYSTEM_MESSAGE_PIPE_DISPATCHER_H_
 #define MOJO_EDK_SYSTEM_MESSAGE_PIPE_DISPATCHER_H_
 
-#include <stddef.h>
 #include <stdint.h>
 
-#include "base/memory/ref_counted.h"
-#include "mojo/edk/embedder/platform_channel_pair.h"
+#include <queue>
+
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
 #include "mojo/edk/system/awakable_list.h"
 #include "mojo/edk/system/dispatcher.h"
-#include "mojo/edk/system/message_in_transit_queue.h"
-#include "mojo/edk/system/raw_channel.h"
-#include "mojo/edk/system/system_impl_export.h"
-#include "mojo/public/cpp/system/macros.h"
-
-namespace base {
-namespace debug {
-class StackTrace;
-}
-}
+#include "mojo/edk/system/ports/port_ref.h"
 
 namespace mojo {
 namespace edk {
 
-// This is the |Dispatcher| implementation for message pipes (created by the
-// Mojo primitive |MojoCreateMessagePipe()|). This class is thread-safe.
-class MOJO_SYSTEM_IMPL_EXPORT MessagePipeDispatcher final
-    : public Dispatcher, public RawChannel::Delegate {
+class NodeController;
+class PortsMessage;
+
+class MessagePipeDispatcher : public Dispatcher {
  public:
-  // The default options to use for |MojoCreateMessagePipe()|. (Real uses
-  // should obtain this via |ValidateCreateOptions()| with a null |in_options|;
-  // this is exposed directly for testing convenience.)
-  static const MojoCreateMessagePipeOptions kDefaultCreateOptions;
+  // Constructs a MessagePipeDispatcher permanently tied to a specific port.
+  // |connected| must indicate the state of the port at construction time; if
+  // the port is initialized with a peer, |connected| must be true. Otherwise it
+  // must be false.
+  //
+  // A MessagePipeDispatcher may not be transferred while in a disconnected
+  // state, and one can never return to a disconnected once connected.
+  //
+  // |pipe_id| is a unique identifier which can be used to track pipe endpoints
+  // as they're passed around. |endpoint| is either 0 or 1 and again is only
+  // used for tracking pipes (one side is always 0, the other is always 1.)
+  MessagePipeDispatcher(NodeController* node_controller,
+                        const ports::PortRef& port,
+                        uint64_t pipe_id,
+                        int endpoint);
 
-  static scoped_refptr<MessagePipeDispatcher> Create(
-      const MojoCreateMessagePipeOptions& validated_options) {
-    return make_scoped_refptr(new MessagePipeDispatcher(
-        !!(validated_options.flags &
-           MOJO_CREATE_MESSAGE_PIPE_OPTIONS_FLAG_TRANSFERABLE)));
-  }
+  // Dispatcher:
+  Type GetType() const override;
+  MojoResult Close() override;
+  MojoResult WriteMessage(const void* bytes,
+                          uint32_t num_bytes,
+                          const DispatcherInTransit* dispatchers,
+                          uint32_t num_dispatchers,
+                          MojoWriteMessageFlags flags) override;
+  MojoResult ReadMessage(void* bytes,
+                         uint32_t* num_bytes,
+                         MojoHandle* handles,
+                         uint32_t* num_handles,
+                         MojoReadMessageFlags flags) override;
+  HandleSignalsState GetHandleSignalsState() const override;
+  MojoResult AddAwakable(Awakable* awakable,
+                         MojoHandleSignals signals,
+                         uintptr_t context,
+                         HandleSignalsState* signals_state) override;
+  void RemoveAwakable(Awakable* awakable,
+                      HandleSignalsState* signals_state) override;
+  void StartSerialize(uint32_t* num_bytes,
+                      uint32_t* num_ports,
+                      uint32_t* num_handles) override;
+  bool EndSerialize(void* destination,
+                    ports::PortName* ports,
+                    PlatformHandle* handles) override;
+  bool BeginTransit() override;
+  void CompleteTransitAndClose() override;
+  void CancelTransit() override;
 
-  // Validates and/or sets default options for |MojoCreateMessagePipeOptions|.
-  // If non-null, |in_options| must point to a struct of at least
-  // |in_options->struct_size| bytes. |out_options| must point to a (current)
-  // |MojoCreateMessagePipeOptions| and will be entirely overwritten on success
-  // (it may be partly overwritten on failure).
-  static MojoResult ValidateCreateOptions(
-      const MojoCreateMessagePipeOptions* in_options,
-      MojoCreateMessagePipeOptions* out_options);
-
-  // Initializes a transferable message pipe.
-  // Must be called before any other methods. (This method is not thread-safe.)
-  void Init(
-      ScopedPlatformHandle message_pipe,
-      char* serialized_read_buffer, size_t serialized_read_buffer_size,
-      char* serialized_write_buffer, size_t serialized_write_buffer_size,
-      std::vector<int>* serialized_read_fds,
-      std::vector<int>* serialized_write_fds);
-
-  // Initializes a nontransferable message pipe.
-  void InitNonTransferable(uint64_t pipe_id);
-
-  // |Dispatcher| public methods:
-  Type GetType() const override;
-
-  // RawChannel::Delegate methods:
-  void OnReadMessage(
-      const MessageInTransit::View& message_view,
-      ScopedPlatformHandleVectorPtr platform_handles) override;
-  void OnError(Error error) override;
-
-  // Called by broker when a route is established between this
-  // MessagePipeDispatcher and another one. This object will receive messages
-  // sent to its pipe_id. It should tag all outgoing messages by calling
-  // MessageInTransit::set_route_id with pipe_id_.
-  void GotNonTransferableChannel(RawChannel* channel);
-
-  // The "opposite" of |SerializeAndClose()|. (Typically this is called by
-  // |Dispatcher::Deserialize()|.)
-  static scoped_refptr<MessagePipeDispatcher> Deserialize(
-      const void* source,
-      size_t size,
-      PlatformHandleVector* platform_handles);
+  static scoped_refptr<Dispatcher> Deserialize(
+      const void* data,
+      size_t num_bytes,
+      const ports::PortName* ports,
+      size_t num_ports,
+      PlatformHandle* handles,
+      size_t num_handles);
 
  private:
-  // See MOJO_CREATE_MESSAGE_PIPE_OPTIONS_FLAG_TRANSFERABLE's definition for an
-  // explanation of what is a transferable pipe.
-  explicit MessagePipeDispatcher(bool transferable);
+  class PortObserverThunk;
+  friend class PortObserverThunk;
+
   ~MessagePipeDispatcher() override;
 
-  void InitOnIO();
-  void CloseOnIOAndRelease();
-  void CloseOnIO();
+  MojoResult CloseNoLock();
+  HandleSignalsState GetHandleSignalsStateNoLock() const;
+  void OnPortStatusChanged();
 
-  // |Dispatcher| protected methods:
-  void CancelAllAwakablesNoLock() override;
-  void CloseImplNoLock() override;
-  scoped_refptr<Dispatcher> CreateEquivalentDispatcherAndCloseImplNoLock()
-      override;
-  MojoResult WriteMessageImplNoLock(
-      const void* bytes,
-      uint32_t num_bytes,
-      std::vector<DispatcherTransport>* transports,
-      MojoWriteMessageFlags flags) override;
-  MojoResult ReadMessageImplNoLock(void* bytes,
-                                   uint32_t* num_bytes,
-                                   DispatcherVector* dispatchers,
-                                   uint32_t* num_dispatchers,
-                                   MojoReadMessageFlags flags) override;
-  HandleSignalsState GetHandleSignalsStateImplNoLock() const override;
-  MojoResult AddAwakableImplNoLock(Awakable* awakable,
-                                   MojoHandleSignals signals,
-                                   uintptr_t context,
-                                   HandleSignalsState* signals_state) override;
-  void RemoveAwakableImplNoLock(Awakable* awakable,
-                                HandleSignalsState* signals_state) override;
-  void StartSerializeImplNoLock(size_t* max_size,
-                                size_t* max_platform_handles) override;
-  bool EndSerializeAndCloseImplNoLock(
-      void* destination,
-      size_t* actual_size,
-      PlatformHandleVector* platform_handles) override;
-  void TransportStarted() override;
-  void TransportEnded() override;
+  // These are safe to access from any thread without locking.
+  NodeController* const node_controller_;
+  const ports::PortRef port_;
+  const uint64_t pipe_id_;
+  const int endpoint_;
 
-  // Calls ReleaseHandle and serializes the raw channel. This is split into a
-  // function because it's called in two different ways:
-  // 1) When serializing "live" dispatchers that are passed to MojoWriteMessage,
-  // CreateEquivalentDispatcherAndCloseImplNoLock calls this.
-  // 2) When serializing dispatchers that are attached to deserialized messages
-  // which haven't been consumed by MojoReadMessage, StartSerializeImplNoLock
-  // calls this.
-  void SerializeInternal();
+  // Guards access to all the fields below.
+  mutable base::Lock signal_lock_;
 
-  MojoResult AttachTransportsNoLock(
-      MessageInTransit* message,
-      std::vector<DispatcherTransport>* transports);
+  // This is not the same is |port_transferred_|. It's only held true between
+  // BeginTransit() and Complete/CancelTransit().
+  bool in_transit_ = false;
 
-  // Called whenever a read or write is done on a non-transferable pipe, which
-  // "binds" the pipe id to this object.
-  void RequestNontransferableChannel();
+  bool port_transferred_ = false;
+  bool port_closed_ = false;
+  AwakableList awakables_;
 
-  // Protected by |lock()|:
-  RawChannel* channel_;
-
-  // Queue of incoming messages that we read from RawChannel but haven't been
-  // consumed through MojoReadMessage yet.
-  MessageInTransitQueue message_queue_;
-
-  // The following members are only used when transferable_ is true;
-
-  // When sending MP, contains serialized message_queue_.
-  std::vector<char> serialized_message_queue_;
-  std::vector<char> serialized_read_buffer_;
-  std::vector<char> serialized_write_buffer_;
-  // Contains FDs from (in this order): the read buffer, the write buffer, and
-  // message queue.
-  std::vector<int> serialized_fds_;
-  size_t serialized_read_fds_length_;
-  size_t serialized_write_fds_length_;
-  size_t serialized_message_fds_length_;
-  ScopedPlatformHandle serialized_platform_handle_;
-
-  // The following members are only used when transferable_ is false;
-
-  // The unique id shared by both ends of a non-transferable message pipe. This
-  // is held on until a read or write are done, and at that point it's used to
-  // get a RawChannel.
-  uint64_t pipe_id_;
-  enum NonTransferableState {
-    // The pipe_id hasn't been bound to this object yet until it's read,
-    // written, or waited on.
-    WAITING_FOR_READ_OR_WRITE,
-    // This object was interacted with, so the pipe_id has been bound and we are
-    // waiting for the broker to connect both sides.
-    CONNECT_CALLED,
-    // We have a connection to the other end of the message pipe.
-    CONNECTED,
-    // This object has been closed before it's connected. To ensure that the
-    // other end receives a closed message from this end, we've initiated
-    // connecting and will close after it succeeds.
-    WAITING_FOR_CONNECT_TO_CLOSE,
-    // The message pipe is closed.
-    CLOSED,
-    // The message pipe has been transferred.
-    SERIALISED,
-  };
-
-  NonTransferableState non_transferable_state_;
-  // Messages that were written while we were waiting to get a RawChannel.
-  MessageInTransitQueue non_transferable_outgoing_message_queue_;
-  scoped_ptr<base::debug::StackTrace> non_transferable_bound_stack_;
-
-
-  // The following members are used for both modes of transferable_.
-
-  AwakableList awakable_list_;
-
-  // If DispatcherTransport is created. Must be set before lock() is called to
-  // avoid deadlocks with RawChannel calling us.
-  base::Lock started_transport_;
-
-  bool serialized_;
-  bool calling_init_;
-  bool write_error_;
-  // Whether it can be sent after read or write.
-  bool transferable_;
-  // When this object is closed, it has to wait to flush any pending messages
-  // from the other side to ensure that any in-queue message pipes are closed.
-  // If this is true, we have already sent the other side the request.
-  bool close_requested_;
-
-  MOJO_DISALLOW_COPY_AND_ASSIGN(MessagePipeDispatcher);
+  DISALLOW_COPY_AND_ASSIGN(MessagePipeDispatcher);
 };
 
 }  // namespace edk
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_MESSAGE_PIPE_DISPATCHER_H_