Resize IPC input buffer to fit the next message.

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 <limits.h>
 
 #include "base/atomic_sequence_num.h"
 #include "base/logging.h"
@@ skipping 113 matching lines @@
   data -= sizeof(int64_t);
   return *(reinterpret_cast<const int64_t*>(data));
 }
 
 void Message::set_received_time(int64_t time) const {
   received_time_ = time;
 }
 #endif
 
 Message::NextMessageInfo::NextMessageInfo()
-    : message_found(false), pickle_end(nullptr), message_end(nullptr) {}
+    : message_size(0), message_found(false), pickle_end(nullptr),
+      message_end(nullptr) {}
 Message::NextMessageInfo::~NextMessageInfo() {}
 
 Message::SerializedAttachmentIds
 Message::SerializedIdsOfBrokerableAttachments() {
   DCHECK(HasBrokerableAttachments());
   std::vector<const BrokerableAttachment*> attachments =
       attachment_set_->PeekBrokerableAttachments();
   CHECK_LE(attachments.size(), std::numeric_limits<size_t>::max() /
                                    BrokerableAttachment::kNonceSize);
   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;
 }
 
 // static
 void Message::FindNext(const char* range_start,
                        const char* range_end,
                        NextMessageInfo* info) {
   DCHECK(info);
-  const char* pickle_end =
-      base::Pickle::FindNext(sizeof(Header), range_start, range_end);
-  if (!pickle_end)
+  info->message_found = false;
+  info->message_size = 0;
+
+  size_t pickle_size = 0;
+  if (!base::Pickle::PeekNext(sizeof(Header),
+                              range_start, range_end, &pickle_size))
     return;
-  info->pickle_end = pickle_end;
+
+  bool have_entire_pickle =
+      static_cast<size_t>(range_end - range_start) >= pickle_size;
 
 #if USE_ATTACHMENT_BROKER
+  // TODO(dskiba): determine message_size when entire pickle is not available
+
+  if (!have_entire_pickle)
+    return;
+
+  const char* pickle_end = range_start + pickle_size;
+
   // 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;
+  Message message(range_start, static_cast<int>(pickle_size));
+  size_t num_attachments = message.header()->num_brokered_attachments;
 
   // Check for possible overflows.
   size_t max_size_t = std::numeric_limits<size_t>::max();
   if (num_attachments >= max_size_t / BrokerableAttachment::kNonceSize)
     return;
 
   size_t attachment_length = num_attachments * BrokerableAttachment::kNonceSize;
-  if (pickle_len > max_size_t - attachment_length)
+  if (pickle_size > max_size_t - attachment_length)
     return;
 
   // Check whether the range includes the attachments.
   size_t buffer_length = static_cast<size_t>(range_end - range_start);
-  if (buffer_length < attachment_length + pickle_len)
+  if (buffer_length < attachment_length + pickle_size)
     return;
 
   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;
+  info->message_size = info->message_end - range_start;
 #else
+  info->message_size = pickle_size;
+
+  if (!have_entire_pickle)
+    return;
+
+  const char* pickle_end = range_start + pickle_size;
+
   info->message_end = pickle_end;
 #endif  // USE_ATTACHMENT_BROKER
 
+  info->pickle_end = pickle_end;
   info->message_found = true;
 }
 
 bool Message::AddPlaceholderBrokerableAttachmentWithId(
     BrokerableAttachment::AttachmentId id) {
   scoped_refptr<PlaceholderBrokerableAttachment> attachment(
       new PlaceholderBrokerableAttachment(id));
   return attachment_set()->AddAttachment(attachment);
 }
 
@@ skipping 26 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