Index: mojo/edk/system/ports/message.h |
diff --git a/mojo/edk/system/ports/message.h b/mojo/edk/system/ports/message.h |
new file mode 100644 |
index 0000000000000000000000000000000000000000..df3b8f2ddbf962e96ff91a890eac4b7993fef1b7 |
--- /dev/null |
+++ b/mojo/edk/system/ports/message.h |
@@ -0,0 +1,91 @@ |
+// Copyright 2016 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_PORTS_MESSAGE_H_ |
+#define MOJO_EDK_SYSTEM_PORTS_MESSAGE_H_ |
+ |
+#include <stddef.h> |
+ |
+#include "base/memory/scoped_ptr.h" |
+#include "mojo/edk/system/ports/name.h" |
+ |
+namespace mojo { |
+namespace edk { |
+namespace ports { |
+ |
+// A message consists of a header (array of bytes), payload (array of bytes) |
+// and an array of ports. The header is used by the Node implementation. |
+// |
+// This class is designed to be subclassed, and the subclass is responsible for |
+// providing the underlying storage. The header size will be aligned, and it |
+// should be followed in memory by the array of ports and finally the payload. |
+// |
+// NOTE: This class does not manage the lifetime of the ports it references. |
+class Message { |
+ public: |
+ virtual ~Message() {} |
+ |
+ // Inspect the message at |bytes| and return the size of each section. |
+ static void Parse(const void* bytes, |
+ size_t num_bytes, |
+ size_t* num_header_bytes, |
+ size_t* num_payload_bytes, |
+ size_t* num_ports_bytes); |
+ |
+ void* mutable_header_bytes() { return start_; } |
+ const void* header_bytes() const { return start_; } |
+ size_t num_header_bytes() const { return num_header_bytes_; } |
+ |
+ void* mutable_payload_bytes() { |
+ return start_ + num_header_bytes_ + num_ports_bytes_; |
+ } |
+ const void* payload_bytes() const { |
+ return const_cast<Message*>(this)->mutable_payload_bytes(); |
+ } |
+ size_t num_payload_bytes() const { return num_payload_bytes_; } |
+ |
+ PortName* mutable_ports() { |
+ return reinterpret_cast<PortName*>(start_ + num_header_bytes_); |
+ } |
+ const PortName* ports() const { |
+ return const_cast<Message*>(this)->mutable_ports(); |
+ } |
+ size_t num_ports_bytes() const { return num_ports_bytes_; } |
+ size_t num_ports() const { return num_ports_bytes_ / sizeof(PortName); } |
+ |
+ protected: |
+ // Constructs a new Message base for a user message. |
+ // |
+ // Note: You MUST call InitializeUserMessageHeader() before this Message is |
+ // ready for transmission. |
+ Message(size_t num_payload_bytes, size_t num_ports); |
+ |
+ // Constructs a new Message base for an internal message. Do NOT call |
+ // InitializeUserMessageHeader() when using this constructor. |
+ Message(size_t num_header_bytes, |
+ size_t num_payload_bytes, |
+ size_t num_ports_bytes); |
+ |
+ Message(const Message& other) = delete; |
+ void operator=(const Message& other) = delete; |
+ |
+ // Initializes the header in a newly allocated message buffer to carry a |
+ // user message. |
+ void InitializeUserMessageHeader(void* start); |
+ |
+ // Note: storage is [header][ports][payload]. |
+ char* start_ = nullptr; |
+ size_t num_ports_ = 0; |
+ size_t num_header_bytes_ = 0; |
+ size_t num_ports_bytes_ = 0; |
+ size_t num_payload_bytes_ = 0; |
+}; |
+ |
+using ScopedMessage = scoped_ptr<Message>; |
+ |
+} // namespace ports |
+} // namespace edk |
+} // namespace mojo |
+ |
+#endif // MOJO_EDK_SYSTEM_PORTS_MESSAGE_H_ |