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 GetRefNumUpper24() {
  26   base::debug::TraceLog* trace_log = base::debug::TraceLog::GetInstance();
  27   uint32 pid = trace_log ? trace_log->process_id() : 0;
  28   uint32 count = g_ref_num.GetNext();
  29   // The 24 bit hash is composed of 14 bits of the count and 10 bits of the
  30   // Process ID. With the current trace event buffer cap, the 14-bit count did
  31   // not appear to wrap during a trace. Note that it is not a big deal if
  32   // collisions occur, as this is only used for debugging and trace analysis.
  33   return ((pid << 14) | (count & 0x3fff)) << 8;
  34 }
  35
  36 }  // namespace
  37
  38 namespace IPC {
  39
  40 //------------------------------------------------------------------------------
  41
  42 Message::~Message() {
  43 }
  44
  45 Message::Message()
  46     : 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 routing_id, uint32 type, PriorityValue priority)
  57     : 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) : Pickle(data, data_len) {
  70   Init();
  71 }
  72
  73 Message::Message(const Message& other) : Pickle(other) {
  74   Init();
  75 #if defined(OS_POSIX)
  76   attachment_set_ = other.attachment_set_;
  77 #endif
  78 }
  79
  80 void Message::Init() {
  81   dispatch_error_ = false;
  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<Pickle*>(this) = other;
  91 #if defined(OS_POSIX)
  92   attachment_set_ = other.attachment_set_;
  93 #endif
  94   return *this;
  95 }
  96
  97 void Message::SetHeaderValues(int32 routing, uint32 type, uint32 flags) {
  98   // This should only be called when the message is already empty.
  99   DCHECK(payload_size() == 0);
 100
 101   header()->routing = routing;
 102   header()->type = type;
 103   header()->flags = flags;
 104 }
 105
 106 void Message::EnsureMessageAttachmentSet() {
 107   if (attachment_set_.get() == NULL)
 108     attachment_set_ = new MessageAttachmentSet;
 109 }
 110
 111 #ifdef IPC_MESSAGE_LOG_ENABLED
 112 void Message::set_sent_time(int64 time) {
 113   DCHECK((header()->flags & HAS_SENT_TIME_BIT) == 0);
 114   header()->flags |= HAS_SENT_TIME_BIT;
 115   WriteInt64(time);
 116 }
 117
 118 int64 Message::sent_time() const {
 119   if ((header()->flags & HAS_SENT_TIME_BIT) == 0)
 120     return 0;
 121
 122   const char* data = end_of_payload();
 123   data -= sizeof(int64);
 124   return *(reinterpret_cast<const int64*>(data));
 125 }
 126
 127 void Message::set_received_time(int64 time) const {
 128   received_time_ = time;
 129 }
 130 #endif
 131
 132 bool Message::WriteAttachment(scoped_refptr<MessageAttachment> attachment) {
 133   // We write the index of the descriptor so that we don't have to
 134   // keep the current descriptor as extra decoding state when deserialising.
 135   WriteInt(attachment_set()->size());
 136   return attachment_set()->AddAttachment(attachment);
 137 }
 138
 139 bool Message::ReadAttachment(
 140     PickleIterator* iter,
 141     scoped_refptr<MessageAttachment>* attachment) const {
 142   int descriptor_index;
 143   if (!iter->ReadInt(&descriptor_index))
 144     return false;
 145
 146   MessageAttachmentSet* attachment_set = attachment_set_.get();
 147   if (!attachment_set)
 148     return false;
 149
 150   *attachment = attachment_set->GetAttachmentAt(descriptor_index);
 151   return nullptr != attachment->get();
 152 }
 153
 154 bool Message::HasAttachments() const {
 155   return attachment_set_.get() && !attachment_set_->empty();
 156 }
 157
 158 bool Message::HasMojoHandles() const {
 159   return attachment_set_.get() && 0 < attachment_set_->num_mojo_handles();
 160 }
 161
 162 }  // namespace IPC