ipc/ipc_message_utils.cc - chromium/src - Git at Google

 // 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_utils.h"

 #include <stddef.h>
 #include <stdint.h>

 #include "base/files/file_path.h"
 #include "base/json/json_writer.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/notreached.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/time/time.h"
 #include "base/unguessable_token.h"
 #include "build/build_config.h"
 #include "ipc/ipc_channel_handle.h"
 #include "ipc/ipc_message.h"
 #include "ipc/ipc_message_attachment.h"
 #include "ipc/ipc_message_attachment_set.h"
 #include "ipc/ipc_mojo_param_traits.h"

 #if BUILDFLAG(IS_APPLE)
 #include "ipc/mach_port_mac.h"
 #endif

 #if BUILDFLAG(IS_WIN)
 #include <tchar.h>
 #include "ipc/handle_win.h"
 #include "ipc/ipc_platform_file.h"
 #elif BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
 #include "base/file_descriptor_posix.h"
 #include "ipc/ipc_platform_file_attachment_posix.h"
 #endif

 #if BUILDFLAG(IS_FUCHSIA)
 #include "base/fuchsia/fuchsia_logging.h"
 #include "ipc/handle_attachment_fuchsia.h"
 #endif

 #if BUILDFLAG(IS_ANDROID)
 #include "base/android/scoped_hardware_buffer_handle.h"
 #include "ipc/ipc_mojo_handle_attachment.h"
 #include "mojo/public/cpp/system/message_pipe.h"
 #include "mojo/public/cpp/system/scope_to_message_pipe.h"
 #endif

 namespace IPC {

 namespace {

 const int kMaxRecursionDepth = 200;

 template<typename CharType>
 void LogBytes(const std::vector<CharType>& data, std::string* out) {
 #if BUILDFLAG(IS_WIN)
   // Windows has a GUI for logging, which can handle arbitrary binary data.
   for (size_t i = 0; i < data.size(); ++i)
     out->push_back(data[i]);
 #elif BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
   // On POSIX, we log to stdout, which we assume can display ASCII.
   static const size_t kMaxBytesToLog = 100;
   for (size_t i = 0; i < std::min(data.size(), kMaxBytesToLog); ++i) {
     if (isprint(data[i]))
       out->push_back(data[i]);
     else
       out->append(
           base::StringPrintf("[%02X]", static_cast<unsigned char>(data[i])));
   }
   if (data.size() > kMaxBytesToLog) {
     out->append(base::StringPrintf(
         " and %u more bytes",
         static_cast<unsigned>(data.size() - kMaxBytesToLog)));
   }
 #endif
 }

 void WriteValue(const base::Value& value, int recursion, base::Pickle* pickle);

 void WriteDictValue(const base::Value::Dict& value,
                     int recursion,
                     base::Pickle* pickle) {
   WriteParam(pickle, base::checked_cast<int>(value.size()));
   for (const auto entry : value) {
     WriteParam(pickle, entry.first);
     WriteValue(entry.second, recursion + 1, pickle);
   }
 }

 void WriteListValue(const base::Value::List& value,
                     int recursion,
                     base::Pickle* pickle) {
   WriteParam(pickle, base::checked_cast<int>(value.size()));
   for (const auto& entry : value) {
     WriteValue(entry, recursion + 1, pickle);
   }
 }

 void WriteValue(const base::Value& value, int recursion, base::Pickle* pickle) {
   bool result;
   if (recursion > kMaxRecursionDepth) {
     LOG(ERROR) << "Max recursion depth hit in WriteValue.";
     return;
   }

   pickle->WriteInt(static_cast<int>(value.type()));

   switch (value.type()) {
     case base::Value::Type::NONE:
       break;
     case base::Value::Type::BOOLEAN: {
       WriteParam(pickle, value.GetBool());
       break;
     }
     case base::Value::Type::INTEGER: {
       DCHECK(value.is_int());
       WriteParam(pickle, value.GetInt());
       break;
     }
     case base::Value::Type::DOUBLE: {
       DCHECK(value.is_int() || value.is_double());
       WriteParam(pickle, value.GetDouble());
       break;
     }
     case base::Value::Type::STRING: {
       const std::string* val = value.GetIfString();
       result = !!val;
       DCHECK(result);
       WriteParam(pickle, *val);
       break;
     }
     case base::Value::Type::BINARY: {
       pickle->WriteData(reinterpret_cast<const char*>(value.GetBlob().data()),
                         value.GetBlob().size());
       break;
     }
     case base::Value::Type::DICT: {
       DCHECK(value.is_dict());
       WriteDictValue(value.GetDict(), recursion, pickle);
       break;
     }
     case base::Value::Type::LIST: {
       DCHECK(value.is_list());
       WriteListValue(value.GetList(), recursion, pickle);
       break;
     }
   }
 }

 bool ReadValue(const base::Pickle* pickle,
                base::PickleIterator* iter,
                int recursion,
                base::Value* value);

 // Helper for ReadValue that reads a Value::Dict into a pre-allocated object.
 bool ReadDictValue(const base::Pickle* pickle,
                    base::PickleIterator* iter,
                    int recursion,
                    base::Value::Dict* value) {
   int size;
   if (!ReadParam(pickle, iter, &size))
     return false;

   for (int i = 0; i < size; i++) {
     std::string key;
     base::Value subvalue;
     if (!ReadParam(pickle, iter, &key) ||
         !ReadValue(pickle, iter, recursion + 1, &subvalue)) {
       return false;
     }
     value->Set(key, std::move(subvalue));
   }

   return true;
 }

 // Helper for ReadValue that reads a Value::List into a pre-allocated object.
 bool ReadListValue(const base::Pickle* pickle,
                    base::PickleIterator* iter,
                    int recursion,
                    base::Value::List* value) {
   int size;
   if (!ReadParam(pickle, iter, &size))
     return false;

   value->reserve(size);
   for (int i = 0; i < size; i++) {
     base::Value subval;
     if (!ReadValue(pickle, iter, recursion + 1, &subval))
       return false;
     value->Append(std::move(subval));
   }
   return true;
 }

 bool ReadValue(const base::Pickle* pickle,
                base::PickleIterator* iter,
                int recursion,
                base::Value* value) {
   if (recursion > kMaxRecursionDepth) {
     LOG(ERROR) << "Max recursion depth hit in ReadValue.";
     return false;
   }

   int type;
   if (!ReadParam(pickle, iter, &type))
     return false;

   constexpr int kMinValueType = static_cast<int>(base::Value::Type::NONE);
   constexpr int kMaxValueType = static_cast<int>(base::Value::Type::LIST);
   if (type > kMaxValueType || type < kMinValueType)
     return false;

   switch (static_cast<base::Value::Type>(type)) {
     case base::Value::Type::NONE:
       *value = base::Value();
       break;
     case base::Value::Type::BOOLEAN: {
       bool val;
       if (!ReadParam(pickle, iter, &val))
         return false;
       *value = base::Value(val);
       break;
     }
     case base::Value::Type::INTEGER: {
       int val;
       if (!ReadParam(pickle, iter, &val))
         return false;
       *value = base::Value(val);
       break;
     }
     case base::Value::Type::DOUBLE: {
       double val;
       if (!ReadParam(pickle, iter, &val))
         return false;
       *value = base::Value(val);
       break;
     }
     case base::Value::Type::STRING: {
       std::string val;
       if (!ReadParam(pickle, iter, &val))
         return false;
       *value = base::Value(std::move(val));
       break;
     }
     case base::Value::Type::BINARY: {
       base::span<const uint8_t> data;
       if (!iter->ReadData(&data))
         return false;
       *value = base::Value(data);
       break;
     }
     case base::Value::Type::DICTIONARY: {
       base::Value::Dict val;
       if (!ReadDictValue(pickle, iter, recursion, &val))
         return false;
       *value = base::Value(std::move(val));
       break;
     }
     case base::Value::Type::LIST: {
       base::Value::List val;
       if (!ReadListValue(pickle, iter, recursion, &val))
         return false;
       *value = base::Value(std::move(val));
       break;
     }
     default:
       NOTREACHED();
       return false;
   }

   return true;
 }

 }  // namespace

 // -----------------------------------------------------------------------------

 LogData::LogData()
     : routing_id(0),
       type(0),
       sent(0),
       receive(0),
       dispatch(0) {
 }

 LogData::LogData(const LogData& other) = default;

 LogData::~LogData() = default;

 void ParamTraits<bool>::Log(const param_type& p, std::string* l) {
   l->append(p ? "true" : "false");
 }

 void ParamTraits<signed char>::Write(base::Pickle* m, const param_type& p) {
   m->WriteBytes(&p, sizeof(param_type));
 }

 bool ParamTraits<signed char>::Read(const base::Pickle* m,
                                     base::PickleIterator* iter,
                                     param_type* r) {
   const char* data;
   if (!iter->ReadBytes(&data, sizeof(param_type)))
     return false;
   memcpy(r, data, sizeof(param_type));
   return true;
 }

 void ParamTraits<signed char>::Log(const param_type& p, std::string* l) {
   l->append(base::NumberToString(p));
 }

 void ParamTraits<unsigned char>::Write(base::Pickle* m, const param_type& p) {
   m->WriteBytes(&p, sizeof(param_type));
 }

 bool ParamTraits<unsigned char>::Read(const base::Pickle* m,
                                       base::PickleIterator* iter,
                                       param_type* r) {
   const char* data;
   if (!iter->ReadBytes(&data, sizeof(param_type)))
     return false;
   memcpy(r, data, sizeof(param_type));
   return true;
 }

 void ParamTraits<unsigned char>::Log(const param_type& p, std::string* l) {
   l->append(base::NumberToString(p));
 }

 void ParamTraits<unsigned short>::Write(base::Pickle* m, const param_type& p) {
   m->WriteBytes(&p, sizeof(param_type));
 }

 bool ParamTraits<unsigned short>::Read(const base::Pickle* m,
                                        base::PickleIterator* iter,
                                        param_type* r) {
   const char* data;
   if (!iter->ReadBytes(&data, sizeof(param_type)))
     return false;
   memcpy(r, data, sizeof(param_type));
   return true;
 }

 void ParamTraits<unsigned short>::Log(const param_type& p, std::string* l) {
   l->append(base::NumberToString(p));
 }

 void ParamTraits<int>::Log(const param_type& p, std::string* l) {
   l->append(base::NumberToString(p));
 }

 void ParamTraits<unsigned int>::Log(const param_type& p, std::string* l) {
   l->append(base::NumberToString(p));
 }

 #if BUILDFLAG(IS_WIN) || BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS) || \
     BUILDFLAG(IS_FUCHSIA) ||                                              \
     (BUILDFLAG(IS_ANDROID) && defined(ARCH_CPU_64_BITS))
 void ParamTraits<long>::Log(const param_type& p, std::string* l) {
   l->append(base::NumberToString(p));
 }

 void ParamTraits<unsigned long>::Log(const param_type& p, std::string* l) {
   l->append(base::NumberToString(p));
 }
 #endif

 void ParamTraits<long long>::Log(const param_type& p, std::string* l) {
   l->append(base::NumberToString(p));
 }

 void ParamTraits<unsigned long long>::Log(const param_type& p, std::string* l) {
   l->append(base::NumberToString(p));
 }

 void ParamTraits<float>::Log(const param_type& p, std::string* l) {
   l->append(base::StringPrintf("%e", p));
 }

 void ParamTraits<double>::Write(base::Pickle* m, const param_type& p) {
   m->WriteBytes(reinterpret_cast<const char*>(&p), sizeof(param_type));
 }

 bool ParamTraits<double>::Read(const base::Pickle* m,
                                base::PickleIterator* iter,
                                param_type* r) {
   const char *data;
   if (!iter->ReadBytes(&data, sizeof(*r))) {
     NOTREACHED();
     return false;
   }
   memcpy(r, data, sizeof(param_type));
   return true;
 }

 void ParamTraits<double>::Log(const param_type& p, std::string* l) {
   l->append(base::StringPrintf("%e", p));
 }


 void ParamTraits<std::string>::Log(const param_type& p, std::string* l) {
   l->append(p);
 }

 void ParamTraits<std::u16string>::Log(const param_type& p, std::string* l) {
   l->append(base::UTF16ToUTF8(p));
 }

 #if BUILDFLAG(IS_WIN)
 bool ParamTraits<std::wstring>::Read(const base::Pickle* m,
                                      base::PickleIterator* iter,
                                      param_type* r) {
   base::StringPiece16 piece16;
   if (!iter->ReadStringPiece16(&piece16))
     return false;

   *r = base::AsWString(piece16);
   return true;
 }

 void ParamTraits<std::wstring>::Log(const param_type& p, std::string* l) {
   l->append(base::WideToUTF8(p));
 }
 #endif

 void ParamTraits<std::vector<char>>::Write(base::Pickle* m,
                                            const param_type& p) {
   if (p.empty()) {
     m->WriteData(NULL, 0);
   } else {
     m->WriteData(&p.front(), p.size());
   }
 }

 bool ParamTraits<std::vector<char>>::Read(const base::Pickle* m,
                                           base::PickleIterator* iter,
                                           param_type* r) {
   const char *data;
   size_t data_size = 0;
   if (!iter->ReadData(&data, &data_size))
     return false;
   r->resize(data_size);
   if (data_size)
     memcpy(&r->front(), data, data_size);
   return true;
 }

 void ParamTraits<std::vector<char> >::Log(const param_type& p, std::string* l) {
   LogBytes(p, l);
 }

 void ParamTraits<std::vector<unsigned char>>::Write(base::Pickle* m,
                                                     const param_type& p) {
   if (p.empty()) {
     m->WriteData(NULL, 0);
   } else {
     m->WriteData(reinterpret_cast<const char*>(&p.front()), p.size());
   }
 }

 bool ParamTraits<std::vector<unsigned char>>::Read(const base::Pickle* m,
                                                    base::PickleIterator* iter,
                                                    param_type* r) {
   const char *data;
   size_t data_size = 0;
   if (!iter->ReadData(&data, &data_size))
     return false;
   r->resize(data_size);
   if (data_size)
     memcpy(&r->front(), data, data_size);
   return true;
 }

 void ParamTraits<std::vector<unsigned char> >::Log(const param_type& p,
                                                    std::string* l) {
   LogBytes(p, l);
 }

 void ParamTraits<std::vector<bool>>::Write(base::Pickle* m,
                                            const param_type& p) {
   WriteParam(m, base::checked_cast<int>(p.size()));
   // Cast to bool below is required because libc++'s
   // vector<bool>::const_reference is different from bool, and we want to avoid
   // writing an extra specialization of ParamTraits for it.
   for (size_t i = 0; i < p.size(); i++)
     WriteParam(m, static_cast<bool>(p[i]));
 }

 bool ParamTraits<std::vector<bool>>::Read(const base::Pickle* m,
                                           base::PickleIterator* iter,
                                           param_type* r) {
   size_t size;
   if (!iter->ReadLength(&size))
     return false;
   r->resize(size);
   for (size_t i = 0; i < size; i++) {
     bool value;
     if (!ReadParam(m, iter, &value))
       return false;
     (*r)[i] = value;
   }
   return true;
 }

 void ParamTraits<std::vector<bool> >::Log(const param_type& p, std::string* l) {
   for (size_t i = 0; i < p.size(); ++i) {
     if (i != 0)
       l->push_back(' ');
     LogParam(static_cast<bool>(p[i]), l);
   }
 }

 void ParamTraits<base::DictionaryValue>::Write(base::Pickle* m,
                                                const param_type& p) {
   WriteDictValue(p.GetDict(), 0, m);
 }

 bool ParamTraits<base::DictionaryValue>::Read(const base::Pickle* m,
                                               base::PickleIterator* iter,
                                               param_type* r) {
   return ReadDictValue(m, iter, 0, &(r->GetDict()));
 }

 void ParamTraits<base::DictionaryValue>::Log(const param_type& p,
                                              std::string* l) {
   std::string json;
   base::JSONWriter::Write(p, &json);
   l->append(json);
 }

 void ParamTraits<base::Value::Dict>::Write(base::Pickle* m,
                                            const param_type& p) {
   WriteDictValue(p, 0, m);
 }

 bool ParamTraits<base::Value::Dict>::Read(const base::Pickle* m,
                                           base::PickleIterator* iter,
                                           param_type* r) {
   return ReadDictValue(m, iter, 0, r);
 }

 void ParamTraits<base::Value::Dict>::Log(const param_type& p, std::string* l) {
   std::string json;
   base::JSONWriter::Write(p, &json);
   l->append(json);
 }

 #if BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
 void ParamTraits<base::FileDescriptor>::Write(base::Pickle* m,
                                               const param_type& p) {
   // This serialization must be kept in sync with
   // nacl_message_scanner.cc:WriteHandle().
   const bool valid = p.fd >= 0;
   WriteParam(m, valid);

   if (!valid)
     return;

   if (p.auto_close) {
     if (!m->WriteAttachment(
             new internal::PlatformFileAttachment(base::ScopedFD(p.fd))))
       NOTREACHED();
   } else {
     if (!m->WriteAttachment(new internal::PlatformFileAttachment(p.fd)))
       NOTREACHED();
   }
 }

 bool ParamTraits<base::FileDescriptor>::Read(const base::Pickle* m,
                                              base::PickleIterator* iter,
                                              param_type* r) {
   *r = base::FileDescriptor();

   bool valid;
   if (!ReadParam(m, iter, &valid))
     return false;

   if (!valid)
     return true;

   scoped_refptr<base::Pickle::Attachment> attachment;
   if (!m->ReadAttachment(iter, &attachment))
     return false;

   if (static_cast<MessageAttachment*>(attachment.get())->GetType() !=
       MessageAttachment::Type::PLATFORM_FILE) {
     return false;
   }

   *r = base::FileDescriptor(
       static_cast<internal::PlatformFileAttachment*>(attachment.get())
           ->TakePlatformFile(),
       true);
   return true;
 }

 void ParamTraits<base::FileDescriptor>::Log(const param_type& p,
                                             std::string* l) {
   if (p.auto_close) {
     l->append(base::StringPrintf("FD(%d auto-close)", p.fd));
   } else {
     l->append(base::StringPrintf("FD(%d)", p.fd));
   }
 }

 void ParamTraits<base::ScopedFD>::Write(base::Pickle* m, const param_type& p) {
   // This serialization must be kept in sync with
   // nacl_message_scanner.cc:WriteHandle().
   const bool valid = p.is_valid();
   WriteParam(m, valid);

   if (!valid)
     return;

   if (!m->WriteAttachment(new internal::PlatformFileAttachment(
           std::move(const_cast<param_type&>(p))))) {
     NOTREACHED();
   }
 }

 bool ParamTraits<base::ScopedFD>::Read(const base::Pickle* m,
                                        base::PickleIterator* iter,
                                        param_type* r) {
   r->reset();

   bool valid;
   if (!ReadParam(m, iter, &valid))
     return false;

   if (!valid)
     return true;

   scoped_refptr<base::Pickle::Attachment> attachment;
   if (!m->ReadAttachment(iter, &attachment))
     return false;

   if (static_cast<MessageAttachment*>(attachment.get())->GetType() !=
       MessageAttachment::Type::PLATFORM_FILE) {
     return false;
   }

   *r = base::ScopedFD(
       static_cast<internal::PlatformFileAttachment*>(attachment.get())
           ->TakePlatformFile());
   return true;
 }

 void ParamTraits<base::ScopedFD>::Log(const param_type& p, std::string* l) {
   l->append(base::StringPrintf("ScopedFD(%d)", p.get()));
 }
 #endif  // BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)

 #if BUILDFLAG(IS_WIN)
 void ParamTraits<base::win::ScopedHandle>::Write(base::Pickle* m,
                                                  const param_type& p) {
   const bool valid = p.IsValid();
   WriteParam(m, valid);
   if (!valid)
     return;

   HandleWin handle(p.Get());
   WriteParam(m, handle);
 }

 bool ParamTraits<base::win::ScopedHandle>::Read(const base::Pickle* m,
                                                 base::PickleIterator* iter,
                                                 param_type* r) {
   r->Close();

   bool valid;
   if (!ReadParam(m, iter, &valid))
     return false;
   if (!valid)
     return true;

   HandleWin handle;
   if (!ReadParam(m, iter, &handle))
     return false;

   r->Set(handle.get_handle());
   return true;
 }

 void ParamTraits<base::win::ScopedHandle>::Log(const param_type& p,
                                                std::string* l) {
   l->append(base::StringPrintf("ScopedHandle(%p)", p.Get()));
 }
 #endif  // BUILDFLAG(IS_WIN)

 #if BUILDFLAG(IS_FUCHSIA)
 void ParamTraits<zx::vmo>::Write(base::Pickle* m, const param_type& p) {
   // This serialization must be kept in sync with
   // nacl_message_scanner.cc:WriteHandle().
   const bool valid = p.is_valid();
   WriteParam(m, valid);

   if (!valid)
     return;

   if (!m->WriteAttachment(new internal::HandleAttachmentFuchsia(
           std::move(const_cast<param_type&>(p))))) {
     NOTREACHED();
   }
 }

 bool ParamTraits<zx::vmo>::Read(const base::Pickle* m,
                                 base::PickleIterator* iter,
                                 param_type* r) {
   r->reset();

   bool valid;
   if (!ReadParam(m, iter, &valid))
     return false;

   if (!valid)
     return true;

   scoped_refptr<base::Pickle::Attachment> attachment;
   if (!m->ReadAttachment(iter, &attachment))
     return false;

   if (static_cast<MessageAttachment*>(attachment.get())->GetType() !=
       MessageAttachment::Type::FUCHSIA_HANDLE) {
     return false;
   }

   *r = zx::vmo(static_cast<internal::HandleAttachmentFuchsia*>(attachment.get())
                    ->Take());
   return true;
 }

 void ParamTraits<zx::vmo>::Log(const param_type& p, std::string* l) {
   l->append("ZirconVMO");
 }

 void ParamTraits<zx::channel>::Write(base::Pickle* m, const param_type& p) {
   // This serialization must be kept in sync with
   // nacl_message_scanner.cc:WriteHandle().
   const bool valid = p.is_valid();
   WriteParam(m, valid);

   if (!valid)
     return;

   if (!m->WriteAttachment(new internal::HandleAttachmentFuchsia(
           std::move(const_cast<param_type&>(p))))) {
     NOTREACHED();
   }
 }

 bool ParamTraits<zx::channel>::Read(const base::Pickle* m,
                                     base::PickleIterator* iter,
                                     param_type* r) {
   r->reset();

   bool valid;
   if (!ReadParam(m, iter, &valid))
     return false;

   if (!valid)
     return true;

   scoped_refptr<base::Pickle::Attachment> attachment;
   if (!m->ReadAttachment(iter, &attachment))
     return false;

   if (static_cast<MessageAttachment*>(attachment.get())->GetType() !=
       MessageAttachment::Type::FUCHSIA_HANDLE) {
     return false;
   }

   *r = zx::channel(
       static_cast<internal::HandleAttachmentFuchsia*>(attachment.get())
           ->Take());
   return true;
 }

 void ParamTraits<zx::channel>::Log(const param_type& p, std::string* l) {
   l->append("ZirconChannel");
 }
 #endif  // BUILDFLAG(IS_FUCHSIA)

 #if BUILDFLAG(IS_ANDROID)
 void ParamTraits<base::android::ScopedHardwareBufferHandle>::Write(
     base::Pickle* m,
     const param_type& p) {
   const bool is_valid = p.is_valid();
   WriteParam(m, is_valid);
   if (!is_valid)
     return;

   // We must keep a ref to the AHardwareBuffer alive until the receiver has
   // acquired its own reference. We do this by sending a message pipe handle
   // along with the buffer. When the receiver deserializes (or even if they
   // die without ever reading the message) their end of the pipe will be
   // closed. We will eventually detect this and release the AHB reference.
   mojo::MessagePipe tracking_pipe;
   m->WriteAttachment(new internal::MojoHandleAttachment(
       mojo::ScopedHandle::From(std::move(tracking_pipe.handle0))));
   WriteParam(m, base::FileDescriptor(p.SerializeAsFileDescriptor().release(),
                                      true /* auto_close */));

   // Pass ownership of the input handle to our tracking pipe to keep the AHB
   // alive long enough to be deserialized by the receiver.
   mojo::ScopeToMessagePipe(std::move(const_cast<param_type&>(p)),
                            std::move(tracking_pipe.handle1));
 }

 bool ParamTraits<base::android::ScopedHardwareBufferHandle>::Read(
     const base::Pickle* m,
     base::PickleIterator* iter,
     param_type* r) {
   *r = base::android::ScopedHardwareBufferHandle();

   bool is_valid;
   if (!ReadParam(m, iter, &is_valid))
     return false;
   if (!is_valid)
     return true;

   scoped_refptr<base::Pickle::Attachment> tracking_pipe_attachment;
   if (!m->ReadAttachment(iter, &tracking_pipe_attachment))
     return false;

   // We keep this alive until the AHB is safely deserialized below. When this
   // goes out of scope, the sender holding the other end of this pipe will treat
   // this handle closure as a signal that it's safe to release their AHB
   // keepalive ref.
   mojo::ScopedHandle tracking_pipe =
       static_cast<MessageAttachment*>(tracking_pipe_attachment.get())
           ->TakeMojoHandle();

   base::FileDescriptor descriptor;
   if (!ReadParam(m, iter, &descriptor))
     return false;

   // NOTE: It is valid to deserialize an invalid FileDescriptor, so the success
   // of |ReadParam()| above does not imply that |descriptor| is valid.
   base::ScopedFD scoped_fd(descriptor.fd);
   if (!scoped_fd.is_valid())
     return false;

   *r = base::android::ScopedHardwareBufferHandle::DeserializeFromFileDescriptor(
       std::move(scoped_fd));
   return true;
 }

 void ParamTraits<base::android::ScopedHardwareBufferHandle>::Log(
     const param_type& p,
     std::string* l) {
   l->append(base::StringPrintf("base::android::ScopedHardwareBufferHandle(%p)",
                                p.get()));
 }
 #endif  // BUILDFLAG(IS_ANDROID)

 void ParamTraits<base::ReadOnlySharedMemoryRegion>::Write(base::Pickle* m,
                                                           const param_type& p) {
   base::subtle::PlatformSharedMemoryRegion handle =
       base::ReadOnlySharedMemoryRegion::TakeHandleForSerialization(
           std::move(const_cast<param_type&>(p)));
   WriteParam(m, std::move(handle));
 }

 bool ParamTraits<base::ReadOnlySharedMemoryRegion>::Read(
     const base::Pickle* m,
     base::PickleIterator* iter,
     param_type* r) {
   base::subtle::PlatformSharedMemoryRegion handle;
   if (!ReadParam(m, iter, &handle))
     return false;

   *r = base::ReadOnlySharedMemoryRegion::Deserialize(std::move(handle));
   return true;
 }

 void ParamTraits<base::ReadOnlySharedMemoryRegion>::Log(const param_type& p,
                                                         std::string* l) {
   *l = "<base::ReadOnlySharedMemoryRegion>";
   // TODO(alexilin): currently there is no way to access underlying handle
   // without destructing a ReadOnlySharedMemoryRegion instance.
 }

 void ParamTraits<base::WritableSharedMemoryRegion>::Write(base::Pickle* m,
                                                           const param_type& p) {
   base::subtle::PlatformSharedMemoryRegion handle =
       base::WritableSharedMemoryRegion::TakeHandleForSerialization(
           std::move(const_cast<param_type&>(p)));
   WriteParam(m, std::move(handle));
 }

 bool ParamTraits<base::WritableSharedMemoryRegion>::Read(
     const base::Pickle* m,
     base::PickleIterator* iter,
     param_type* r) {
   base::subtle::PlatformSharedMemoryRegion handle;
   if (!ReadParam(m, iter, &handle))
     return false;

   *r = base::WritableSharedMemoryRegion::Deserialize(std::move(handle));
   return true;
 }

 void ParamTraits<base::WritableSharedMemoryRegion>::Log(const param_type& p,
                                                         std::string* l) {
   *l = "<base::WritableSharedMemoryRegion>";
   // TODO(alexilin): currently there is no way to access underlying handle
   // without destructing a ReadOnlySharedMemoryRegion instance.
 }

 void ParamTraits<base::UnsafeSharedMemoryRegion>::Write(base::Pickle* m,
                                                         const param_type& p) {
   base::subtle::PlatformSharedMemoryRegion handle =
       base::UnsafeSharedMemoryRegion::TakeHandleForSerialization(
           std::move(const_cast<param_type&>(p)));
   WriteParam(m, std::move(handle));
 }

 bool ParamTraits<base::UnsafeSharedMemoryRegion>::Read(
     const base::Pickle* m,
     base::PickleIterator* iter,
     param_type* r) {
   base::subtle::PlatformSharedMemoryRegion handle;
   if (!ReadParam(m, iter, &handle))
     return false;

   *r = base::UnsafeSharedMemoryRegion::Deserialize(std::move(handle));
   return true;
 }

 void ParamTraits<base::UnsafeSharedMemoryRegion>::Log(const param_type& p,
                                                       std::string* l) {
   *l = "<base::UnsafeSharedMemoryRegion>";
   // TODO(alexilin): currently there is no way to access underlying handle
   // without destructing a ReadOnlySharedMemoryRegion instance.
 }

 void ParamTraits<base::subtle::PlatformSharedMemoryRegion>::Write(
     base::Pickle* m,
     const param_type& p) {
   // This serialization must be kept in sync with
   // nacl_message_scanner.cc::WriteHandle().
   const bool valid = p.IsValid();
   WriteParam(m, valid);

   if (!valid)
     return;

   WriteParam(m, p.GetMode());
   WriteParam(m, static_cast<uint64_t>(p.GetSize()));
   WriteParam(m, p.GetGUID());

 #if BUILDFLAG(IS_WIN)
   base::win::ScopedHandle h = const_cast<param_type&>(p).PassPlatformHandle();
   HandleWin handle_win(h.Get());
   WriteParam(m, handle_win);
 #elif BUILDFLAG(IS_FUCHSIA)
   zx::vmo vmo = const_cast<param_type&>(p).PassPlatformHandle();
   WriteParam(m, vmo);
 #elif BUILDFLAG(IS_APPLE)
   base::mac::ScopedMachSendRight h =
       const_cast<param_type&>(p).PassPlatformHandle();
   MachPortMac mach_port_mac(h.get());
   WriteParam(m, mach_port_mac);
 #elif BUILDFLAG(IS_ANDROID)
   m->WriteAttachment(new internal::PlatformFileAttachment(
       base::ScopedFD(const_cast<param_type&>(p).PassPlatformHandle())));
 #elif BUILDFLAG(IS_POSIX)
   base::subtle::ScopedFDPair h =
       const_cast<param_type&>(p).PassPlatformHandle();
   m->WriteAttachment(new internal::PlatformFileAttachment(std::move(h.fd)));
   if (p.GetMode() ==
       base::subtle::PlatformSharedMemoryRegion::Mode::kWritable) {
     m->WriteAttachment(
         new internal::PlatformFileAttachment(std::move(h.readonly_fd)));
   }
 #endif
 }

 bool ParamTraits<base::subtle::PlatformSharedMemoryRegion>::Read(
     const base::Pickle* m,
     base::PickleIterator* iter,
     param_type* r) {
   bool valid;
   if (!ReadParam(m, iter, &valid))
     return false;
   if (!valid) {
     *r = base::subtle::PlatformSharedMemoryRegion();
     return true;
   }

   base::subtle::PlatformSharedMemoryRegion::Mode mode;
   uint64_t shm_size;
   base::UnguessableToken guid;
   if (!ReadParam(m, iter, &mode) || !ReadParam(m, iter, &shm_size) ||
       !base::IsValueInRangeForNumericType<size_t>(shm_size) ||
       !ReadParam(m, iter, &guid)) {
     return false;
   }
   size_t size = static_cast<size_t>(shm_size);

 #if BUILDFLAG(IS_WIN)
   HandleWin handle_win;
   if (!ReadParam(m, iter, &handle_win))
     return false;
   *r = base::subtle::PlatformSharedMemoryRegion::Take(
       base::win::ScopedHandle(handle_win.get_handle()), mode, size, guid);
 #elif BUILDFLAG(IS_FUCHSIA)
   zx::vmo vmo;
   if (!ReadParam(m, iter, &vmo))
     return false;
   *r = base::subtle::PlatformSharedMemoryRegion::Take(std::move(vmo), mode,
                                                       size, guid);
 #elif BUILDFLAG(IS_APPLE)
   MachPortMac mach_port_mac;
   if (!ReadParam(m, iter, &mach_port_mac))
     return false;
   *r = base::subtle::PlatformSharedMemoryRegion::Take(
       base::mac::ScopedMachSendRight(mach_port_mac.get_mach_port()), mode, size,
       guid);
 #elif BUILDFLAG(IS_POSIX)
   scoped_refptr<base::Pickle::Attachment> attachment;
   if (!m->ReadAttachment(iter, &attachment))
     return false;
   if (static_cast<MessageAttachment*>(attachment.get())->GetType() !=
       MessageAttachment::Type::PLATFORM_FILE) {
     return false;
   }

 #if BUILDFLAG(IS_ANDROID)
   *r = base::subtle::PlatformSharedMemoryRegion::Take(
       base::ScopedFD(
           static_cast<internal::PlatformFileAttachment*>(attachment.get())
               ->TakePlatformFile()),
       mode, size, guid);
 #else
   scoped_refptr<base::Pickle::Attachment> readonly_attachment;
   if (mode == base::subtle::PlatformSharedMemoryRegion::Mode::kWritable) {
     if (!m->ReadAttachment(iter, &readonly_attachment))
       return false;

     if (static_cast<MessageAttachment*>(readonly_attachment.get())->GetType() !=
         MessageAttachment::Type::PLATFORM_FILE) {
       return false;
     }
   }
   *r = base::subtle::PlatformSharedMemoryRegion::Take(
       base::subtle::ScopedFDPair(
           base::ScopedFD(
               static_cast<internal::PlatformFileAttachment*>(attachment.get())
                   ->TakePlatformFile()),
           readonly_attachment
               ? base::ScopedFD(static_cast<internal::PlatformFileAttachment*>(
                                    readonly_attachment.get())
                                    ->TakePlatformFile())
               : base::ScopedFD()),
       mode, size, guid);
 #endif  // BUILDFLAG(IS_ANDROID)

 #endif

   return true;
 }

 void ParamTraits<base::subtle::PlatformSharedMemoryRegion>::Log(
     const param_type& p,
     std::string* l) {
 #if BUILDFLAG(IS_FUCHSIA)
   l->append("Handle: ");
   LogParam(p.GetPlatformHandle()->get(), l);
 #elif BUILDFLAG(IS_WIN)
   l->append("Handle: ");
   LogParam(p.GetPlatformHandle(), l);
 #elif BUILDFLAG(IS_APPLE)
   l->append("Mach port: ");
   LogParam(p.GetPlatformHandle(), l);
 #elif BUILDFLAG(IS_ANDROID)
   l->append("FD: ");
   LogParam(p.GetPlatformHandle(), l);
 #elif BUILDFLAG(IS_POSIX)
   base::subtle::FDPair h = p.GetPlatformHandle();
   l->append("FD: ");
   LogParam(h.fd, l);
   l->append("Read-only FD: ");
   LogParam(h.readonly_fd, l);
 #endif

   l->append("Mode: ");
   LogParam(p.GetMode(), l);
   l->append("size: ");
   LogParam(static_cast<uint64_t>(p.GetSize()), l);
   l->append("GUID: ");
   LogParam(p.GetGUID(), l);
 }

 void ParamTraits<base::subtle::PlatformSharedMemoryRegion::Mode>::Write(
     base::Pickle* m,
     const param_type& value) {
   DCHECK(static_cast<int>(value) >= 0 &&
          static_cast<int>(value) <= static_cast<int>(param_type::kMaxValue));
   m->WriteInt(static_cast<int>(value));
 }

 bool ParamTraits<base::subtle::PlatformSharedMemoryRegion::Mode>::Read(
     const base::Pickle* m,
     base::PickleIterator* iter,
     param_type* p) {
   int value;
   if (!iter->ReadInt(&value))
     return false;
   if (!(static_cast<int>(value) >= 0 &&
         static_cast<int>(value) <= static_cast<int>(param_type::kMaxValue))) {
     return false;
   }
   *p = static_cast<param_type>(value);
   return true;
 }

 void ParamTraits<base::subtle::PlatformSharedMemoryRegion::Mode>::Log(
     const param_type& p,
     std::string* l) {
   LogParam(static_cast<int>(p), l);
 }

 #if BUILDFLAG(IS_WIN)
 void ParamTraits<PlatformFileForTransit>::Write(base::Pickle* m,
                                                 const param_type& p) {
   m->WriteBool(p.IsValid());
   if (p.IsValid()) {
     HandleWin handle_win(p.GetHandle());
     ParamTraits<HandleWin>::Write(m, handle_win);
     ::CloseHandle(p.GetHandle());
   }
 }

 bool ParamTraits<PlatformFileForTransit>::Read(const base::Pickle* m,
                                                base::PickleIterator* iter,
                                                param_type* r) {
   bool is_valid;
   if (!iter->ReadBool(&is_valid))
     return false;
   if (!is_valid) {
     *r = PlatformFileForTransit();
     return true;
   }

   HandleWin handle_win;
   if (!ParamTraits<HandleWin>::Read(m, iter, &handle_win))
     return false;
   *r = PlatformFileForTransit(handle_win.get_handle());
   return true;
 }

 void ParamTraits<PlatformFileForTransit>::Log(const param_type& p,
                                               std::string* l) {
   LogParam(p.GetHandle(), l);
 }
 #endif  // BUILDFLAG(IS_WIN)

 void ParamTraits<base::FilePath>::Write(base::Pickle* m, const param_type& p) {
   p.WriteToPickle(m);
 }

 bool ParamTraits<base::FilePath>::Read(const base::Pickle* m,
                                        base::PickleIterator* iter,
                                        param_type* r) {
   return r->ReadFromPickle(iter);
 }

 void ParamTraits<base::FilePath>::Log(const param_type& p, std::string* l) {
   ParamTraits<base::FilePath::StringType>::Log(p.value(), l);
 }

 void ParamTraits<base::ListValue>::Write(base::Pickle* m, const param_type& p) {
   WriteListValue(p.GetList(), 0, m);
 }

 bool ParamTraits<base::ListValue>::Read(const base::Pickle* m,
                                         base::PickleIterator* iter,
                                         param_type* r) {
   return ReadListValue(m, iter, 0, &(r->GetList()));
 }

 void ParamTraits<base::ListValue>::Log(const param_type& p, std::string* l) {
   std::string json;
   base::JSONWriter::Write(p, &json);
   l->append(json);
 }

 void ParamTraits<base::Value::List>::Write(base::Pickle* m,
                                            const param_type& p) {
   WriteListValue(p, 0, m);
 }

 bool ParamTraits<base::Value::List>::Read(const base::Pickle* m,
                                           base::PickleIterator* iter,
                                           param_type* r) {
   return ReadListValue(m, iter, 0, r);
 }

 void ParamTraits<base::Value::List>::Log(const param_type& p, std::string* l) {
   std::string json;
   base::JSONWriter::Write(p, &json);
   l->append(json);
 }

 void ParamTraits<base::Value>::Write(base::Pickle* m, const param_type& p) {
   WriteValue(p, 0, m);
 }

 bool ParamTraits<base::Value>::Read(const base::Pickle* m,
                                     base::PickleIterator* iter,
                                     param_type* r) {
   return ReadValue(m, iter, 0, r);
 }

 void ParamTraits<base::Value>::Log(const param_type& p, std::string* l) {
   std::string json;
   base::JSONWriter::Write(p, &json);
   l->append(json);
 }

 void ParamTraits<base::File::Info>::Write(base::Pickle* m,
                                           const param_type& p) {
   WriteParam(m, p.size);
   WriteParam(m, p.is_directory);
   WriteParam(m, p.last_modified.ToDoubleT());
   WriteParam(m, p.last_accessed.ToDoubleT());
   WriteParam(m, p.creation_time.ToDoubleT());
 }

 bool ParamTraits<base::File::Info>::Read(const base::Pickle* m,
                                          base::PickleIterator* iter,
                                          param_type* p) {
   double last_modified, last_accessed, creation_time;
   if (!ReadParam(m, iter, &p->size) ||
       !ReadParam(m, iter, &p->is_directory) ||
       !ReadParam(m, iter, &last_modified) ||
       !ReadParam(m, iter, &last_accessed) ||
       !ReadParam(m, iter, &creation_time))
     return false;
   p->last_modified = base::Time::FromDoubleT(last_modified);
   p->last_accessed = base::Time::FromDoubleT(last_accessed);
   p->creation_time = base::Time::FromDoubleT(creation_time);
   return true;
 }

 void ParamTraits<base::File::Info>::Log(const param_type& p,
                                         std::string* l) {
   l->append("(");
   LogParam(p.size, l);
   l->append(",");
   LogParam(p.is_directory, l);
   l->append(",");
   LogParam(p.last_modified.ToDoubleT(), l);
   l->append(",");
   LogParam(p.last_accessed.ToDoubleT(), l);
   l->append(",");
   LogParam(p.creation_time.ToDoubleT(), l);
   l->append(")");
 }

 void ParamTraits<base::Time>::Write(base::Pickle* m, const param_type& p) {
   ParamTraits<int64_t>::Write(m, p.ToInternalValue());
 }

 bool ParamTraits<base::Time>::Read(const base::Pickle* m,
                                    base::PickleIterator* iter,
                                    param_type* r) {
   int64_t value;
   if (!ParamTraits<int64_t>::Read(m, iter, &value))
     return false;
   *r = base::Time::FromInternalValue(value);
   return true;
 }

 void ParamTraits<base::Time>::Log(const param_type& p, std::string* l) {
   ParamTraits<int64_t>::Log(p.ToInternalValue(), l);
 }

 void ParamTraits<base::TimeDelta>::Write(base::Pickle* m, const param_type& p) {
   ParamTraits<int64_t>::Write(m, p.ToInternalValue());
 }

 bool ParamTraits<base::TimeDelta>::Read(const base::Pickle* m,
                                         base::PickleIterator* iter,
                                         param_type* r) {
   int64_t value;
   bool ret = ParamTraits<int64_t>::Read(m, iter, &value);
   if (ret)
     *r = base::TimeDelta::FromInternalValue(value);

   return ret;
 }

 void ParamTraits<base::TimeDelta>::Log(const param_type& p, std::string* l) {
   ParamTraits<int64_t>::Log(p.ToInternalValue(), l);
 }

 void ParamTraits<base::TimeTicks>::Write(base::Pickle* m, const param_type& p) {
   ParamTraits<int64_t>::Write(m, p.ToInternalValue());
 }

 bool ParamTraits<base::TimeTicks>::Read(const base::Pickle* m,
                                         base::PickleIterator* iter,
                                         param_type* r) {
   int64_t value;
   bool ret = ParamTraits<int64_t>::Read(m, iter, &value);
   if (ret)
     *r = base::TimeTicks::FromInternalValue(value);

   return ret;
 }

 void ParamTraits<base::TimeTicks>::Log(const param_type& p, std::string* l) {
   ParamTraits<int64_t>::Log(p.ToInternalValue(), l);
 }

 // If base::UnguessableToken is no longer 128 bits, the IPC serialization logic
 // below should be updated.
 static_assert(sizeof(base::UnguessableToken) == 2 * sizeof(uint64_t),
               "base::UnguessableToken should be of size 2 * sizeof(uint64_t).");

 void ParamTraits<base::UnguessableToken>::Write(base::Pickle* m,
                                                 const param_type& p) {
   DCHECK(!p.is_empty());

   ParamTraits<uint64_t>::Write(m, p.GetHighForSerialization());
   ParamTraits<uint64_t>::Write(m, p.GetLowForSerialization());
 }

 bool ParamTraits<base::UnguessableToken>::Read(const base::Pickle* m,
                                                base::PickleIterator* iter,
                                                param_type* r) {
   uint64_t high, low;
   if (!ParamTraits<uint64_t>::Read(m, iter, &high) ||
       !ParamTraits<uint64_t>::Read(m, iter, &low))
     return false;

   // Receiving a zeroed UnguessableToken is a security issue.
   if (high == 0 && low == 0)
     return false;

   *r = base::UnguessableToken::Deserialize(high, low);
   return true;
 }

 void ParamTraits<base::UnguessableToken>::Log(const param_type& p,
                                               std::string* l) {
   l->append(p.ToString());
 }

 void ParamTraits<IPC::ChannelHandle>::Write(base::Pickle* m,
                                             const param_type& p) {
 #if BUILDFLAG(IS_NACL)
   WriteParam(m, p.socket);
 #else
   WriteParam(m, p.mojo_handle);
 #endif
 }

 bool ParamTraits<IPC::ChannelHandle>::Read(const base::Pickle* m,
                                            base::PickleIterator* iter,
                                            param_type* r) {
 #if BUILDFLAG(IS_NACL)
   return ReadParam(m, iter, &r->socket);
 #else
   return ReadParam(m, iter, &r->mojo_handle);
 #endif
 }

 void ParamTraits<IPC::ChannelHandle>::Log(const param_type& p,
                                           std::string* l) {
   l->append("ChannelHandle(");
 #if BUILDFLAG(IS_NACL)
   ParamTraits<base::FileDescriptor>::Log(p.socket, l);
 #else
   LogParam(p.mojo_handle, l);
 #endif
   l->append(")");
 }

 void ParamTraits<LogData>::Write(base::Pickle* m, const param_type& p) {
   WriteParam(m, p.channel);
   WriteParam(m, p.routing_id);
   WriteParam(m, p.type);
   WriteParam(m, p.flags);
   WriteParam(m, p.sent);
   WriteParam(m, p.receive);
   WriteParam(m, p.dispatch);
   WriteParam(m, p.message_name);
   WriteParam(m, p.params);
 }

 bool ParamTraits<LogData>::Read(const base::Pickle* m,
                                 base::PickleIterator* iter,
                                 param_type* r) {
   return
       ReadParam(m, iter, &r->channel) &&
       ReadParam(m, iter, &r->routing_id) &&
       ReadParam(m, iter, &r->type) &&
       ReadParam(m, iter, &r->flags) &&
       ReadParam(m, iter, &r->sent) &&
       ReadParam(m, iter, &r->receive) &&
       ReadParam(m, iter, &r->dispatch) &&
       ReadParam(m, iter, &r->message_name) &&
       ReadParam(m, iter, &r->params);
 }

 void ParamTraits<LogData>::Log(const param_type& p, std::string* l) {
   // Doesn't make sense to implement this!
 }

 void ParamTraits<Message>::Write(base::Pickle* m, const Message& p) {
 #if BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
   // We don't serialize the file descriptors in the nested message, so there
   // better not be any.
   DCHECK(!p.HasAttachments());
 #endif

   // Don't just write out the message. This is used to send messages between
   // NaCl (Posix environment) and the browser (could be on Windows). The message
   // header formats differ between these systems (so does handle sharing, but
   // we already asserted we don't have any handles). So just write out the
   // parts of the header we use.
   //
   // Be careful also to use only explicitly-sized types. The NaCl environment
   // could be 64-bit and the host browser could be 32-bits. The nested message
   // may or may not be safe to send between 32-bit and 64-bit systems, but we
   // leave that up to the code sending the message to ensure.
   m->WriteUInt32(static_cast<uint32_t>(p.routing_id()));
   m->WriteUInt32(p.type());
   m->WriteUInt32(p.flags());
   m->WriteData(p.payload(), p.payload_size());
 }

 bool ParamTraits<Message>::Read(const base::Pickle* m,
                                 base::PickleIterator* iter,
                                 Message* r) {
   uint32_t routing_id, type, flags;
   if (!iter->ReadUInt32(&routing_id) ||
       !iter->ReadUInt32(&type) ||
       !iter->ReadUInt32(&flags))
     return false;

   size_t payload_size;
   const char* payload;
   if (!iter->ReadData(&payload, &payload_size))
     return false;

   r->SetHeaderValues(static_cast<int32_t>(routing_id), type, flags);
   r->WriteBytes(payload, payload_size);
   return true;
 }

 void ParamTraits<Message>::Log(const Message& p, std::string* l) {
   l->append("<IPC::Message>");
 }

 #if BUILDFLAG(IS_WIN)
 // Note that HWNDs/HANDLE/HCURSOR/HACCEL etc are always 32 bits, even on 64
 // bit systems. That's why we use the Windows macros to convert to 32 bits.
 void ParamTraits<HANDLE>::Write(base::Pickle* m, const param_type& p) {
   m->WriteInt(HandleToLong(p));
 }

 bool ParamTraits<HANDLE>::Read(const base::Pickle* m,
                                base::PickleIterator* iter,
                                param_type* r) {
   int32_t temp;
   if (!iter->ReadInt(&temp))
     return false;
   *r = LongToHandle(temp);
   return true;
 }

 void ParamTraits<HANDLE>::Log(const param_type& p, std::string* l) {
   l->append(base::StringPrintf("0x%p", p));
 }

 void ParamTraits<MSG>::Write(base::Pickle* m, const param_type& p) {
   m->WriteData(reinterpret_cast<const char*>(&p), sizeof(MSG));
 }

 bool ParamTraits<MSG>::Read(const base::Pickle* m,
                             base::PickleIterator* iter,
                             param_type* r) {
   const char *data;
   size_t data_size = 0;
   bool result = iter->ReadData(&data, &data_size);
   if (result && data_size == sizeof(MSG)) {
     memcpy(r, data, sizeof(MSG));
   } else {
     result = false;
     NOTREACHED();
   }

   return result;
 }

 void ParamTraits<MSG>::Log(const param_type& p, std::string* l) {
   l->append("<MSG>");
 }

 #endif  // BUILDFLAG(IS_WIN)

 }  // namespace IPC