Initial in-process implementation of some Mojo primitives.

mojo/system/message_pipe.h

+// Copyright 2013 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_SYSTEM_MESSAGE_PIPE_H_
+#define MOJO_SYSTEM_MESSAGE_PIPE_H_
+
+#include <list>
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/synchronization/lock.h"
+#include "mojo/public/system/core.h"
+#include "mojo/system/waiter_list.h"
+
+namespace mojo {
+namespace system {
+
+class Waiter;
+
+// |MessagePipe| is the secondary object implementing a message pipe (see the
+// explanatory comment in core_impl.cc), and is jointly owned by the two
+// dispatchers passed in to the constructor. This class is thread-safe.
+class MessagePipe : public base::RefCountedThreadSafe<MessagePipe> {
+ public:
+  MessagePipe();
+
+  // These are called by the dispatcher to implement its methods of
+  // corresponding names. In all cases, the port |port| must be open.
+  void CancelAllWaiters(unsigned port);
+  void Close(unsigned port);
+  MojoResult WriteMessage(unsigned port,
+                          const void* bytes, uint32_t num_bytes,
+                          const MojoHandle* handles, uint32_t num_handles,
+                          MojoWriteMessageFlags flags);
+  MojoResult ReadMessage(unsigned port,
+                         void* bytes, uint32_t* num_bytes,
+                         MojoHandle* handles, uint32_t* num_handles,
+                         MojoReadMessageFlags flags);
+  MojoResult AddWaiter(unsigned port,
+                       Waiter* waiter,
+                       MojoWaitFlags flags,
+                       MojoResult wake_result);
+  void RemoveWaiter(unsigned port, Waiter* waiter);
+
+ private:
+  struct MessageInTransit {
+    MessageInTransit(const void* bytes, uint32_t num_bytes)
+        : data(static_cast<const char*>(bytes), num_bytes) {}
+
+    // TODO(vtl): Replace with something more efficient.
+    std::string data;
+  };
+
+  friend class base::RefCountedThreadSafe<MessagePipe>;
+  virtual ~MessagePipe();
+
+  MojoWaitFlags SatisfiedFlagsNoLock(unsigned port);
+  MojoWaitFlags SatisfiableFlagsNoLock(unsigned port);
+
+  base::Lock lock_;  // Protects the following members.
+  bool is_open_[2];
+  // These are *incoming* queues for their corresponding ports. It owns its
+  // contents.
+  // TODO(vtl): When possible (with C++11), convert the plain pointers to
+  // scoped_ptr/unique_ptr. (Then we'll be able to use an |std::queue| instead
+  // of an |std::list|.)
+  std::list<MessageInTransit*> message_queues_[2];
+  WaiterList waiter_lists_[2];
+
+  DISALLOW_COPY_AND_ASSIGN(MessagePipe);
+};
+
+}  // namespace system
+}  // namespace mojo
+
+#endif  // MOJO_SYSTEM_MESSAGE_PIPE_H_