ipc/ipc_message.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "ipc/ipc_message.h"
   6
   7 #include "base/atomic_sequence_num.h"
   8 #include "base/logging.h"
   9 #include "build/build_config.h"
  10 #include "ipc/ipc_message_attachment.h"
  11 #include "ipc/ipc_message_attachment_set.h"
  12
  13 #if defined(OS_POSIX)
  14 #include "base/file_descriptor_posix.h"
  15 #include "ipc/ipc_platform_file_attachment_posix.h"
  16 #endif
  17
  18 namespace {
  19
  20 base::StaticAtomicSequenceNumber g_ref_num;
  21
  22 // Create a reference number for identifying IPC messages in traces. The return
  23 // values has the reference number stored in the upper 24 bits, leaving the low
  24 // 8 bits set to 0 for use as flags.
  25 inline uint32_t GetRefNumUpper24() {
  26   base::trace_event::TraceLog* trace_log =
  27       base::trace_event::TraceLog::GetInstance();
  28   uint32_t pid = trace_log ? trace_log->process_id() : 0;
  29   uint32_t count = g_ref_num.GetNext();
  30   // The 24 bit hash is composed of 14 bits of the count and 10 bits of the
  31   // Process ID. With the current trace event buffer cap, the 14-bit count did
  32   // not appear to wrap during a trace. Note that it is not a big deal if
  33   // collisions occur, as this is only used for debugging and trace analysis.
  34   return ((pid << 14) | (count & 0x3fff)) << 8;
  35 }
  36
  37 }  // namespace
  38
  39 namespace IPC {
  40
  41 //------------------------------------------------------------------------------
  42
  43 Message::~Message() {
  44 }
  45
  46 Message::Message() : base::Pickle(sizeof(Header)) {
  47   header()->routing = header()->type = 0;
  48   header()->flags = GetRefNumUpper24();
  49 #if defined(OS_POSIX)
  50   header()->num_fds = 0;
  51   header()->pad = 0;
  52 #endif
  53   Init();
  54 }
  55
  56 Message::Message(int32_t routing_id, uint32_t type, PriorityValue priority)
  57     : base::Pickle(sizeof(Header)) {
  58   header()->routing = routing_id;
  59   header()->type = type;
  60   DCHECK((priority & 0xffffff00) == 0);
  61   header()->flags = priority | GetRefNumUpper24();
  62 #if defined(OS_POSIX)
  63   header()->num_fds = 0;
  64   header()->pad = 0;
  65 #endif
  66   Init();
  67 }
  68
  69 Message::Message(const char* data, int data_len)
  70     : base::Pickle(data, data_len) {
  71   Init();
  72 }
  73
  74 Message::Message(const Message& other) : base::Pickle(other) {
  75   Init();
  76   attachment_set_ = other.attachment_set_;
  77 }
  78
  79 void Message::Init() {
  80   dispatch_error_ = false;
  81   sender_pid_ = base::kNullProcessId;
  82 #ifdef IPC_MESSAGE_LOG_ENABLED
  83   received_time_ = 0;
  84   dont_log_ = false;
  85   log_data_ = NULL;
  86 #endif
  87 }
  88
  89 Message& Message::operator=(const Message& other) {
  90   *static_cast<base::Pickle*>(this) = other;
  91   attachment_set_ = other.attachment_set_;
  92   return *this;
  93 }
  94
  95 void Message::SetHeaderValues(int32_t routing, uint32_t type, uint32_t flags) {
  96   // This should only be called when the message is already empty.
  97   DCHECK(payload_size() == 0);
  98
  99   header()->routing = routing;
 100   header()->type = type;
 101   header()->flags = flags;
 102 }
 103
 104 void Message::EnsureMessageAttachmentSet() {
 105   if (attachment_set_.get() == NULL)
 106     attachment_set_ = new MessageAttachmentSet;
 107 }
 108
 109 #ifdef IPC_MESSAGE_LOG_ENABLED
 110 void Message::set_sent_time(int64_t time) {
 111   DCHECK((header()->flags & HAS_SENT_TIME_BIT) == 0);
 112   header()->flags |= HAS_SENT_TIME_BIT;
 113   WriteInt64(time);
 114 }
 115
 116 int64_t Message::sent_time() const {
 117   if ((header()->flags & HAS_SENT_TIME_BIT) == 0)
 118     return 0;
 119
 120   const char* data = end_of_payload();
 121   data -= sizeof(int64_t);
 122   return *(reinterpret_cast<const int64_t*>(data));
 123 }
 124
 125 void Message::set_received_time(int64_t time) const {
 126   received_time_ = time;
 127 }
 128 #endif
 129
 130 bool Message::WriteAttachment(scoped_refptr<MessageAttachment> attachment) {
 131   // We write the index of the descriptor so that we don't have to
 132   // keep the current descriptor as extra decoding state when deserialising.
 133   WriteInt(attachment_set()->size());
 134   return attachment_set()->AddAttachment(attachment);
 135 }
 136
 137 bool Message::ReadAttachment(
 138     base::PickleIterator* iter,
 139     scoped_refptr<MessageAttachment>* attachment) const {
 140   int descriptor_index;
 141   if (!iter->ReadInt(&descriptor_index))
 142     return false;
 143
 144   MessageAttachmentSet* attachment_set = attachment_set_.get();
 145   if (!attachment_set)
 146     return false;
 147
 148   *attachment = attachment_set->GetAttachmentAt(descriptor_index);
 149   return nullptr != attachment->get();
 150 }
 151
 152 bool Message::HasAttachments() const {
 153   return attachment_set_.get() && !attachment_set_->empty();
 154 }
 155
 156 bool Message::HasMojoHandles() const {
 157   return attachment_set_.get() && attachment_set_->num_mojo_handles() > 0;
 158 }
 159
 160 bool Message::HasBrokerableAttachments() const {
 161   return attachment_set_.get() &&
 162          attachment_set_->num_brokerable_attachments() > 0;
 163 }
 164
 165 }  // namespace IPC