IPC: Add attachment brokering support to the message header.

ipc/ipc_message.cc

 // Copyright (c) 2012 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 "ipc/ipc_message.h"
 
 #include "base/atomic_sequence_num.h"
 #include "base/logging.h"
 #include "build/build_config.h"
 #include "ipc/ipc_message_attachment.h"
 #include "ipc/ipc_message_attachment_set.h"
+#include "ipc/placeholder_brokerable_attachment.h"
 
 #if defined(OS_POSIX)
 #include "base/file_descriptor_posix.h"
 #include "ipc/ipc_platform_file_attachment_posix.h"
 #endif
 
 namespace {
 
 base::StaticAtomicSequenceNumber g_ref_num;
 
@@ skipping 17 matching lines @@
 namespace IPC {
 
 //------------------------------------------------------------------------------
 
 Message::~Message() {
 }
 
 Message::Message() : base::Pickle(sizeof(Header)) {
   header()->routing = header()->type = 0;
   header()->flags = GetRefNumUpper24();
+#if USE_ATTACHMENT_BROKER
+  header()->num_brokered_attachments = 0;
+#endif
 #if defined(OS_POSIX)
   header()->num_fds = 0;
   header()->pad = 0;
 #endif
   Init();
 }
 
 Message::Message(int32 routing_id, uint32 type, PriorityValue priority)
     : base::Pickle(sizeof(Header)) {
   header()->routing = routing_id;
   header()->type = type;
   DCHECK((priority & 0xffffff00) == 0);
   header()->flags = priority | GetRefNumUpper24();
+#if USE_ATTACHMENT_BROKER
+  header()->num_brokered_attachments = 0;
+#endif
 #if defined(OS_POSIX)
   header()->num_fds = 0;
   header()->pad = 0;
 #endif
   Init();
 }
 
 Message::Message(const char* data, int data_len)
     : base::Pickle(data, data_len) {
   Init();
@@ skipping 48 matching lines @@
   const char* data = end_of_payload();
   data -= sizeof(int64);
   return *(reinterpret_cast<const int64*>(data));
 }
 
 void Message::set_received_time(int64 time) const {
   received_time_ = time;
 }
 #endif
 
+Message::NextMessageInfo::NextMessageInfo()
+    : message_found(false), pickle_end(nullptr), message_end(nullptr) {}
+Message::NextMessageInfo::~NextMessageInfo() {}
+
+// static
+Message::NextMessageInfo Message::FindNext(const char* range_start,
+                                           const char* range_end) {
+  NextMessageInfo info;
+  const char* pickle_end =
+      base::Pickle::FindNext(sizeof(Header), range_start, range_end);
+  if (pickle_end == nullptr)
+    return info;
+  info.pickle_end = pickle_end;
+
+#if USE_ATTACHMENT_BROKER
+  // The data is not copied.
+  size_t pickle_len = static_cast<size_t>(pickle_end - range_start);
+  Message message(range_start, static_cast<int>(pickle_len));
+  int num_attachments = message.header()->num_brokered_attachments;
+
+  // Each brokered attachment adds kNonceSize bytes of data to the message. We
+  // want to avoid overflows in our computations, so we limit the number of
+  // brokerable attachments to 100.
+  if (num_attachments > 100)
+    return info;
+
+  // Check whether the range includes the attachments.
+  size_t attachment_length = num_attachments * BrokerableAttachment::kNonceSize;
+  size_t buffer_length = static_cast<size_t>(range_end - range_start);
+  if (buffer_length < attachment_length + pickle_len)
+    return info;
+
+  for (int i = 0; i < num_attachments; ++i) {
+    const char* attachment_start =
+        pickle_end + i * (BrokerableAttachment::kNonceSize);
+    BrokerableAttachment::AttachmentId id(attachment_start,
+                                          BrokerableAttachment::kNonceSize);
+    info.attachment_ids.push_back(id);
+  }
+  info.message_end =
+      pickle_end + num_attachments * BrokerableAttachment::kNonceSize;
+#else
+  info.message_end = pickle_end;
+#endif  // USE_ATTACHMENT_BROKER
+
+  info.message_found = true;
+  return info;
+}
+
+Message::SerializedAttachmentIds
+Message::SerializedIdsOfBrokerableAttachments() {
+  DCHECK(HasBrokerableAttachments());
+  std::vector<const BrokerableAttachment*> attachments =
+      attachment_set_->PeekBrokerableAttachments();
+  size_t size = attachments.size() * BrokerableAttachment::kNonceSize;
+  char* buffer = static_cast<char*>(malloc(size));
+  for (size_t i = 0; i < attachments.size(); ++i) {
+    const BrokerableAttachment* attachment = attachments[i];
+    char* start_range = buffer + i * BrokerableAttachment::kNonceSize;
+    BrokerableAttachment::AttachmentId id = attachment->GetIdentifier();
+    id.SerializeToBuffer(start_range, BrokerableAttachment::kNonceSize);
+  }
+  SerializedAttachmentIds ids;
+  ids.buffer = buffer;
+  ids.size = size;
+  return ids;
+}
+
+bool Message::AddPlaceholderBrokerableAttachmentWithId(
+    BrokerableAttachment::AttachmentId id) {
+  scoped_refptr<PlaceholderBrokerableAttachment> attachment(
+      new PlaceholderBrokerableAttachment(id));
+  return attachment_set()->AddAttachment(attachment);
+}
+
 bool Message::WriteAttachment(scoped_refptr<MessageAttachment> attachment) {
   // We write the index of the descriptor so that we don't have to
   // keep the current descriptor as extra decoding state when deserialising.
   WriteInt(attachment_set()->size());
+
+#if USE_ATTACHMENT_BROKER
+  if (attachment->GetType() == MessageAttachment::TYPE_BROKERABLE_ATTACHMENT)
+    header()->num_brokered_attachments += 1;
+#endif
+
   return attachment_set()->AddAttachment(attachment);
 }
 
 bool Message::ReadAttachment(
     base::PickleIterator* iter,
     scoped_refptr<MessageAttachment>* attachment) const {
   int descriptor_index;
   if (!iter->ReadInt(&descriptor_index))
     return false;
 
@@ skipping 12 matching lines @@
 bool Message::HasMojoHandles() const {
   return attachment_set_.get() && attachment_set_->num_mojo_handles() > 0;
 }
 
 bool Message::HasBrokerableAttachments() const {
   return attachment_set_.get() &&
          attachment_set_->num_brokerable_attachments() > 0;
 }
 
 }  // namespace IPC