[mojo] Ports EDK

mojo/edk/system/ports/message.cc

+// 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.
+
+#include <stdlib.h>
+
+#include <limits>
+
+#include "base/logging.h"
+#include "mojo/edk/system/ports/event.h"
+
+namespace mojo {
+namespace edk {
+namespace ports {
+
+// static
+void Message::Parse(const void* bytes,
+                    size_t num_bytes,
+                    size_t* num_header_bytes,
+                    size_t* num_payload_bytes,
+                    size_t* num_ports_bytes) {
+  const EventHeader* header = static_cast<const EventHeader*>(bytes);
+  switch (header->type) {
+    case EventType::kUser:
+      // See below.
+      break;
+    case EventType::kPortAccepted:
+      *num_header_bytes = sizeof(EventHeader);
+      break;
+    case EventType::kObserveProxy:
+      *num_header_bytes = sizeof(EventHeader) + sizeof(ObserveProxyEventData);
+      break;
+    case EventType::kObserveProxyAck:
+      *num_header_bytes =
+          sizeof(EventHeader) + sizeof(ObserveProxyAckEventData);
+      break;
+    case EventType::kObserveClosure:
+      *num_header_bytes = sizeof(EventHeader) + sizeof(ObserveClosureEventData);
+      break;
+    default:
+      CHECK(false) << "Bad event type";
+      return;
+  }
+
+  if (header->type == EventType::kUser) {
+    const UserEventData* event_data =
+        reinterpret_cast<const UserEventData*>(
+            reinterpret_cast<const char*>(header + 1));
+    *num_header_bytes = sizeof(EventHeader) +
+                        sizeof(UserEventData) +
+                        event_data->num_ports * sizeof(PortDescriptor);
+    *num_ports_bytes = event_data->num_ports * sizeof(PortName);
+    *num_payload_bytes = num_bytes - *num_header_bytes - *num_ports_bytes;
+  } else {
+    *num_payload_bytes = 0;
+    *num_ports_bytes = 0;
+    DCHECK_EQ(num_bytes, *num_header_bytes);
+  }
+}
+
+Message::Message(size_t num_payload_bytes, size_t num_ports)
+    : Message(sizeof(EventHeader) + sizeof(UserEventData) +
+                  num_ports * sizeof(PortDescriptor),
+              num_payload_bytes, num_ports * sizeof(PortName)) {
+  num_ports_ = num_ports;
+}
+
+Message::Message(size_t num_header_bytes,
+                 size_t num_payload_bytes,
+                 size_t num_ports_bytes)
+    : start_(nullptr),
+      num_header_bytes_(num_header_bytes),
+      num_ports_bytes_(num_ports_bytes),
+      num_payload_bytes_(num_payload_bytes) {
+}
+
+void Message::InitializeUserMessageHeader(void* start) {
+  start_ = static_cast<char*>(start);
+  memset(start_, 0, num_header_bytes_);
+  GetMutableEventHeader(this)->type = EventType::kUser;
+  GetMutableEventData<UserEventData>(this)->num_ports =
+      static_cast<uint32_t>(num_ports_);
+}
+
+}  // namespace ports
+}  // namespace edk
+}  // namespace mojo