Separates ipc code from common (http://crbug.com/16829)

ipc/ipc_message_utils.h

+// Copyright (c) 2006-2009 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.
+
+#ifndef IPC_IPC_MESSAGE_UTILS_H_
+#define IPC_IPC_MESSAGE_UTILS_H_
+
+#include <string>
+#include <vector>
+#include <map>
+
+#include "base/file_path.h"
+#include "base/format_macros.h"
+#include "base/string16.h"
+#include "base/string_util.h"
+#include "base/time.h"
+#include "base/tuple.h"
+#include "base/values.h"
+#if defined(OS_POSIX)
+#include "ipc/file_descriptor_set_posix.h"
+#endif
+#include "ipc/ipc_channel_handle.h"
+#include "ipc/ipc_sync_message.h"
+
+// Used by IPC_BEGIN_MESSAGES so that each message class starts from a unique
+// base.  Messages have unique IDs across channels in order for the IPC logging
+// code to figure out the message class from its ID.
+enum IPCMessageStart {
+  // By using a start value of 0 for automation messages, we keep backward
+  // compatibility with old builds.
+  AutomationMsgStart = 0,
+  ViewMsgStart,
+  ViewHostMsgStart,
+  PluginProcessMsgStart,
+  PluginProcessHostMsgStart,
+  PluginMsgStart,
+  PluginHostMsgStart,
+  NPObjectMsgStart,
+  TestMsgStart,
+  DevToolsAgentMsgStart,
+  DevToolsClientMsgStart,
+  WorkerProcessMsgStart,
+  WorkerProcessHostMsgStart,
+  WorkerMsgStart,
+  WorkerHostMsgStart,
+  // NOTE: When you add a new message class, also update
+  // IPCStatusView::IPCStatusView to ensure logging works.
+  // NOTE: this enum is used by IPC_MESSAGE_MACRO to generate a unique message
+  // id.  Only 4 bits are used for the message type, so if this enum needs more
+  // than 16 entries, that code needs to be updated.
+  LastMsgIndex
+};
+
+COMPILE_ASSERT(LastMsgIndex <= 16, need_to_update_IPC_MESSAGE_MACRO);
+
+
+namespace IPC {
+
+//-----------------------------------------------------------------------------
+// An iterator class for reading the fields contained within a Message.
+
+class MessageIterator {
+ public:
+  explicit MessageIterator(const Message& m) : msg_(m), iter_(NULL) {
+  }
+  int NextInt() const {
+    int val;
+    if (!msg_.ReadInt(&iter_, &val))
+      NOTREACHED();
+    return val;
+  }
+  intptr_t NextIntPtr() const {
+    intptr_t val;
+    if (!msg_.ReadIntPtr(&iter_, &val))
+      NOTREACHED();
+    return val;
+  }
+  const std::string NextString() const {
+    std::string val;
+    if (!msg_.ReadString(&iter_, &val))
+      NOTREACHED();
+    return val;
+  }
+  const std::wstring NextWString() const {
+    std::wstring val;
+    if (!msg_.ReadWString(&iter_, &val))
+      NOTREACHED();
+    return val;
+  }
+  const void NextData(const char** data, int* length) const {
+    if (!msg_.ReadData(&iter_, data, length)) {
+      NOTREACHED();
+    }
+  }
+ private:
+  const Message& msg_;
+  mutable void* iter_;
+};
+
+//-----------------------------------------------------------------------------
+// ParamTraits specializations, etc.
+
+template <class P> struct ParamTraits {};
+
+template <class P>
+static inline void WriteParam(Message* m, const P& p) {
+  ParamTraits<P>::Write(m, p);
+}
+
+template <class P>
+static inline bool WARN_UNUSED_RESULT ReadParam(const Message* m, void** iter,
+                                                P* p) {
+  return ParamTraits<P>::Read(m, iter, p);
+}
+
+template <class P>
+static inline void LogParam(const P& p, std::wstring* l) {
+  ParamTraits<P>::Log(p, l);
+}
+
+template <>
+struct ParamTraits<bool> {
+  typedef bool param_type;
+  static void Write(Message* m, const param_type& p) {
+    m->WriteBool(p);
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    return m->ReadBool(iter, r);
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    l->append(p ? L"true" : L"false");
+  }
+};
+
+template <>
+struct ParamTraits<int> {
+  typedef int param_type;
+  static void Write(Message* m, const param_type& p) {
+    m->WriteInt(p);
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    return m->ReadInt(iter, r);
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    l->append(StringPrintf(L"%d", p));
+  }
+};
+
+template <>
+struct ParamTraits<long> {
+  typedef long param_type;
+  static void Write(Message* m, const param_type& p) {
+    m->WriteLong(p);
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    return m->ReadLong(iter, r);
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    l->append(StringPrintf(L"%l", p));
+  }
+};
+
+#if defined(OS_LINUX) || defined(OS_WIN)
+// On Linux, unsigned long is used for serializing X window ids.
+// On Windows, it's used for serializing process ids.
+// On Mac, it conflicts with some other definition.
+template <>
+struct ParamTraits<unsigned long> {
+  typedef unsigned long param_type;
+  static void Write(Message* m, const param_type& p) {
+    m->WriteLong(p);
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    long read_output;
+    if (!m->ReadLong(iter, &read_output))
+      return false;
+    *r = static_cast<unsigned long>(read_output);
+    return true;
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    l->append(StringPrintf(L"%ul", p));
+  }
+};
+#endif
+
+template <>
+struct ParamTraits<size_t> {
+  typedef size_t param_type;
+  static void Write(Message* m, const param_type& p) {
+    m->WriteSize(p);
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    return m->ReadSize(iter, r);
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    l->append(StringPrintf(L"%u", p));
+  }
+};
+
+#if defined(OS_MACOSX)
+// On Linux size_t & uint32 can be the same type.
+// TODO(playmobil): Fix compilation if this is not the case.
+template <>
+struct ParamTraits<uint32> {
+  typedef uint32 param_type;
+  static void Write(Message* m, const param_type& p) {
+    m->WriteUInt32(p);
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    return m->ReadUInt32(iter, r);
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    l->append(StringPrintf(L"%u", p));
+  }
+};
+#endif  // defined(OS_MACOSX)
+
+template <>
+struct ParamTraits<int64> {
+  typedef int64 param_type;
+  static void Write(Message* m, const param_type& p) {
+    m->WriteInt64(p);
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    return m->ReadInt64(iter, r);
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    l->append(StringPrintf(L"%" WidePRId64, p));
+  }
+};
+
+template <>
+struct ParamTraits<uint64> {
+  typedef uint64 param_type;
+  static void Write(Message* m, const param_type& p) {
+    m->WriteInt64(static_cast<int64>(p));
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    return m->ReadInt64(iter, reinterpret_cast<int64*>(r));
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    l->append(StringPrintf(L"%" WidePRId64, p));
+  }
+};
+
+template <>
+struct ParamTraits<double> {
+  typedef double param_type;
+  static void Write(Message* m, const param_type& p) {
+    m->WriteData(reinterpret_cast<const char*>(&p), sizeof(param_type));
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    const char *data;
+    int data_size = 0;
+    bool result = m->ReadData(iter, &data, &data_size);
+    if (result && data_size == sizeof(param_type)) {
+      memcpy(r, data, sizeof(param_type));
+    } else {
+      result = false;
+      NOTREACHED();
+    }
+
+    return result;
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    l->append(StringPrintf(L"e", p));
+  }
+};
+
+template <>
+struct ParamTraits<wchar_t> {
+  typedef wchar_t param_type;
+  static void Write(Message* m, const param_type& p) {
+    m->WriteData(reinterpret_cast<const char*>(&p), sizeof(param_type));
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    const char *data;
+    int data_size = 0;
+    bool result = m->ReadData(iter, &data, &data_size);
+    if (result && data_size == sizeof(param_type)) {
+      memcpy(r, data, sizeof(param_type));
+    } else {
+      result = false;
+      NOTREACHED();
+    }
+
+    return result;
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    l->append(StringPrintf(L"%lc", p));
+  }
+};
+
+template <>
+struct ParamTraits<base::Time> {
+  typedef base::Time param_type;
+  static void Write(Message* m, const param_type& p) {
+    ParamTraits<int64>::Write(m, p.ToInternalValue());
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    int64 value;
+    if (!ParamTraits<int64>::Read(m, iter, &value))
+      return false;
+    *r = base::Time::FromInternalValue(value);
+    return true;
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    ParamTraits<int64>::Log(p.ToInternalValue(), l);
+  }
+};
+
+#if defined(OS_WIN)
+template <>
+struct ParamTraits<LOGFONT> {
+  typedef LOGFONT param_type;
+  static void Write(Message* m, const param_type& p) {
+    m->WriteData(reinterpret_cast<const char*>(&p), sizeof(LOGFONT));
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    const char *data;
+    int data_size = 0;
+    bool result = m->ReadData(iter, &data, &data_size);
+    if (result && data_size == sizeof(LOGFONT)) {
+      memcpy(r, data, sizeof(LOGFONT));
+    } else {
+      result = false;
+      NOTREACHED();
+    }
+
+    return result;
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    l->append(StringPrintf(L"<LOGFONT>"));
+  }
+};
+
+template <>
+struct ParamTraits<MSG> {
+  typedef MSG param_type;
+  static void Write(Message* m, const param_type& p) {
+    m->WriteData(reinterpret_cast<const char*>(&p), sizeof(MSG));
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    const char *data;
+    int data_size = 0;
+    bool result = m->ReadData(iter, &data, &data_size);
+    if (result && data_size == sizeof(MSG)) {
+      memcpy(r, data, sizeof(MSG));
+    } else {
+      result = false;
+      NOTREACHED();
+    }
+
+    return result;
+  }
+};
+#endif  // defined(OS_WIN)
+
+template <>
+struct ParamTraits<DictionaryValue> {
+  typedef DictionaryValue param_type;
+  static void Write(Message* m, const param_type& p);
+  static bool Read(const Message* m, void** iter, param_type* r);
+  static void Log(const param_type& p, std::wstring* l);
+};
+
+template <>
+struct ParamTraits<ListValue> {
+  typedef ListValue param_type;
+  static void Write(Message* m, const param_type& p);
+  static bool Read(const Message* m, void** iter, param_type* r);
+  static void Log(const param_type& p, std::wstring* l);
+};
+
+template <>
+struct ParamTraits<std::string> {
+  typedef std::string param_type;
+  static void Write(Message* m, const param_type& p) {
+    m->WriteString(p);
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    return m->ReadString(iter, r);
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    l->append(UTF8ToWide(p));
+  }
+};
+
+template <>
+struct ParamTraits<std::vector<unsigned char> > {
+  typedef std::vector<unsigned char> param_type;
+  static void Write(Message* m, const param_type& p) {
+    if (p.size() == 0) {
+      m->WriteData(NULL, 0);
+    } else {
+      m->WriteData(reinterpret_cast<const char*>(&p.front()),
+                   static_cast<int>(p.size()));
+    }
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    const char *data;
+    int data_size = 0;
+    if (!m->ReadData(iter, &data, &data_size) || data_size < 0)
+      return false;
+    r->resize(data_size);
+    if (data_size)
+      memcpy(&r->front(), data, data_size);
+    return true;
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    for (size_t i = 0; i < p.size(); ++i)
+      l->push_back(p[i]);
+  }
+};
+
+template <>
+struct ParamTraits<std::vector<char> > {
+  typedef std::vector<char> param_type;
+  static void Write(Message* m, const param_type& p) {
+    if (p.size() == 0) {
+      m->WriteData(NULL, 0);
+    } else {
+      m->WriteData(&p.front(), static_cast<int>(p.size()));
+    }
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    const char *data;
+    int data_size = 0;
+    if (!m->ReadData(iter, &data, &data_size) || data_size < 0)
+      return false;
+    r->resize(data_size);
+    if (data_size)
+      memcpy(&r->front(), data, data_size);
+    return true;
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    for (size_t i = 0; i < p.size(); ++i)
+      l->push_back(p[i]);
+  }
+};
+
+template <class P>
+struct ParamTraits<std::vector<P> > {
+  typedef std::vector<P> param_type;
+  static void Write(Message* m, const param_type& p) {
+    WriteParam(m, static_cast<int>(p.size()));
+    for (size_t i = 0; i < p.size(); i++)
+      WriteParam(m, p[i]);
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    int size;
+    if (!m->ReadLength(iter, &size))
+      return false;
+    // Resizing beforehand is not safe, see BUG 1006367 for details.
+    if (m->IteratorHasRoomFor(*iter, size * sizeof(P))) {
+      r->resize(size);
+      for (int i = 0; i < size; i++) {
+        if (!ReadParam(m, iter, &(*r)[i]))
+          return false;
+      }
+    } else {
+      for (int i = 0; i < size; i++) {
+        P element;
+        if (!ReadParam(m, iter, &element))
+          return false;
+        r->push_back(element);
+      }
+    }
+    return true;
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    for (size_t i = 0; i < p.size(); ++i) {
+      if (i != 0)
+        l->append(L" ");
+
+      LogParam((p[i]), l);
+    }
+  }
+};
+
+template <class K, class V>
+struct ParamTraits<std::map<K, V> > {
+  typedef std::map<K, V> param_type;
+  static void Write(Message* m, const param_type& p) {
+    WriteParam(m, static_cast<int>(p.size()));
+    typename param_type::const_iterator iter;
+    for (iter = p.begin(); iter != p.end(); ++iter) {
+      WriteParam(m, iter->first);
+      WriteParam(m, iter->second);
+    }
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    int size;
+    if (!ReadParam(m, iter, &size) || size < 0)
+      return false;
+    for (int i = 0; i < size; ++i) {
+      K k;
+      if (!ReadParam(m, iter, &k))
+        return false;
+      V& value = (*r)[k];
+      if (!ReadParam(m, iter, &value))
+        return false;
+    }
+    return true;
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    l->append(L"<std::map>");
+  }
+};
+
+
+template <>
+struct ParamTraits<std::wstring> {
+  typedef std::wstring param_type;
+  static void Write(Message* m, const param_type& p) {
+    m->WriteWString(p);
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    return m->ReadWString(iter, r);
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    l->append(p);
+  }
+};
+
+// If WCHAR_T_IS_UTF16 is defined, then string16 is a std::wstring so we don't
+// need this trait.
+#if !defined(WCHAR_T_IS_UTF16)
+template <>
+struct ParamTraits<string16> {
+  typedef string16 param_type;
+  static void Write(Message* m, const param_type& p) {
+    m->WriteString16(p);
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    return m->ReadString16(iter, r);
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    l->append(UTF16ToWide(p));
+  }
+};
+#endif
+
+// and, a few more useful types...
+#if defined(OS_WIN)
+template <>
+struct ParamTraits<HANDLE> {
+  typedef HANDLE param_type;
+  static void Write(Message* m, const param_type& p) {
+    m->WriteIntPtr(reinterpret_cast<intptr_t>(p));
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    DCHECK_EQ(sizeof(param_type), sizeof(intptr_t));
+    return m->ReadIntPtr(iter, reinterpret_cast<intptr_t*>(r));
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    l->append(StringPrintf(L"0x%X", p));
+  }
+};
+
+template <>
+struct ParamTraits<HCURSOR> {
+  typedef HCURSOR param_type;
+  static void Write(Message* m, const param_type& p) {
+    m->WriteIntPtr(reinterpret_cast<intptr_t>(p));
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    DCHECK_EQ(sizeof(param_type), sizeof(intptr_t));
+    return m->ReadIntPtr(iter, reinterpret_cast<intptr_t*>(r));
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    l->append(StringPrintf(L"0x%X", p));
+  }
+};
+
+template <>
+struct ParamTraits<HACCEL> {
+  typedef HACCEL param_type;
+  static void Write(Message* m, const param_type& p) {
+    m->WriteIntPtr(reinterpret_cast<intptr_t>(p));
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    DCHECK_EQ(sizeof(param_type), sizeof(intptr_t));
+    return m->ReadIntPtr(iter, reinterpret_cast<intptr_t*>(r));
+  }
+};
+
+template <>
+struct ParamTraits<POINT> {
+  typedef POINT param_type;
+  static void Write(Message* m, const param_type& p) {
+    m->WriteInt(p.x);
+    m->WriteInt(p.y);
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    int x, y;
+    if (!m->ReadInt(iter, &x) || !m->ReadInt(iter, &y))
+      return false;
+    r->x = x;
+    r->y = y;
+    return true;
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    l->append(StringPrintf(L"(%d, %d)", p.x, p.y));
+  }
+};
+#endif  // defined(OS_WIN)
+
+template <>
+struct ParamTraits<FilePath> {
+  typedef FilePath param_type;
+  static void Write(Message* m, const param_type& p) {
+    ParamTraits<FilePath::StringType>::Write(m, p.value());
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    FilePath::StringType value;
+    if (!ParamTraits<FilePath::StringType>::Read(m, iter, &value))
+      return false;
+    *r = FilePath(value);
+    return true;
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    ParamTraits<FilePath::StringType>::Log(p.value(), l);
+  }
+};
+
+#if defined(OS_POSIX)
+// FileDescriptors may be serialised over IPC channels on POSIX. On the
+// receiving side, the FileDescriptor is a valid duplicate of the file
+// descriptor which was transmitted: *it is not just a copy of the integer like
+// HANDLEs on Windows*. The only exception is if the file descriptor is < 0. In
+// this case, the receiving end will see a value of -1. *Zero is a valid file
+// descriptor*.
+//
+// The received file descriptor will have the |auto_close| flag set to true. The
+// code which handles the message is responsible for taking ownership of it.
+// File descriptors are OS resources and must be closed when no longer needed.
+//
+// When sending a file descriptor, the file descriptor must be valid at the time
+// of transmission. Since transmission is not synchronous, one should consider
+// dup()ing any file descriptors to be transmitted and setting the |auto_close|
+// flag, which causes the file descriptor to be closed after writing.
+template<>
+struct ParamTraits<base::FileDescriptor> {
+  typedef base::FileDescriptor param_type;
+  static void Write(Message* m, const param_type& p) {
+    const bool valid = p.fd >= 0;
+    WriteParam(m, valid);
+
+    if (valid) {
+      if (!m->WriteFileDescriptor(p))
+        NOTREACHED();
+    }
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    bool valid;
+    if (!ReadParam(m, iter, &valid))
+      return false;
+
+    if (!valid) {
+      r->fd = -1;
+      r->auto_close = false;
+      return true;
+    }
+
+    return m->ReadFileDescriptor(iter, r);
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    if (p.auto_close) {
+      l->append(StringPrintf(L"FD(%d auto-close)", p.fd));
+    } else {
+      l->append(StringPrintf(L"FD(%d)", p.fd));
+    }
+  }
+};
+#endif // defined(OS_POSIX)
+
+// A ChannelHandle is basically a platform-inspecific wrapper around the
+// fact that IPC endpoints are handled specially on POSIX.  See above comments
+// on FileDescriptor for more background.
+template<>
+struct ParamTraits<IPC::ChannelHandle> {
+  typedef ChannelHandle param_type;
+  static void Write(Message* m, const param_type& p) {
+    WriteParam(m, p.name);
+#if defined(OS_POSIX)
+    WriteParam(m, p.socket);
+#endif
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    return ReadParam(m, iter, &r->name)
+#if defined(OS_POSIX)
+        && ReadParam(m, iter, &r->socket)
+#endif
+        ;
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    l->append(ASCIIToWide(StringPrintf("ChannelHandle(%s", p.name.c_str())));
+#if defined(OS_POSIX)
+    ParamTraits<base::FileDescriptor>::Log(p.socket, l);
+#endif
+    l->append(L")");
+  }
+};
+
+#if defined(OS_WIN)
+template <>
+struct ParamTraits<XFORM> {
+  typedef XFORM param_type;
+  static void Write(Message* m, const param_type& p) {
+    m->WriteData(reinterpret_cast<const char*>(&p), sizeof(XFORM));
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    const char *data;
+    int data_size = 0;
+    bool result = m->ReadData(iter, &data, &data_size);
+    if (result && data_size == sizeof(XFORM)) {
+      memcpy(r, data, sizeof(XFORM));
+    } else {
+      result = false;
+      NOTREACHED();
+    }
+
+    return result;
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    l->append(L"<XFORM>");
+  }
+};
+#endif  // defined(OS_WIN)
+
+struct LogData {
+  std::string channel;
+  int32 routing_id;
+  uint16 type;
+  std::wstring flags;
+  int64 sent;  // Time that the message was sent (i.e. at Send()).
+  int64 receive;  // Time before it was dispatched (i.e. before calling
+                  // OnMessageReceived).
+  int64 dispatch;  // Time after it was dispatched (i.e. after calling
+                   // OnMessageReceived).
+  std::wstring message_name;
+  std::wstring params;
+};
+
+template <>
+struct ParamTraits<LogData> {
+  typedef LogData param_type;
+  static void Write(Message* m, const param_type& p) {
+    WriteParam(m, p.channel);
+    WriteParam(m, p.routing_id);
+    WriteParam(m, static_cast<int>(p.type));
+    WriteParam(m, p.flags);
+    WriteParam(m, p.sent);
+    WriteParam(m, p.receive);
+    WriteParam(m, p.dispatch);
+    WriteParam(m, p.params);
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    int type;
+    bool result =
+      ReadParam(m, iter, &r->channel) &&
+      ReadParam(m, iter, &r->routing_id);
+      ReadParam(m, iter, &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->params);
+    r->type = static_cast<uint16>(type);
+    return result;
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    // Doesn't make sense to implement this!
+  }
+};
+
+
+template <>
+struct ParamTraits<Message> {
+  static void Write(Message* m, const Message& p) {
+    m->WriteInt(p.size());
+    m->WriteData(reinterpret_cast<const char*>(p.data()), p.size());
+  }
+  static bool Read(const Message* m, void** iter, Message* r) {
+    int size;
+    if (!m->ReadInt(iter, &size))
+      return false;
+    const char* data;
+    if (!m->ReadData(iter, &data, &size))
+      return false;
+    *r = Message(data, size);
+    return true;
+  }
+  static void Log(const Message& p, std::wstring* l) {
+    l->append(L"<IPC::Message>");
+  }
+};
+
+template <>
+struct ParamTraits<Tuple0> {
+  typedef Tuple0 param_type;
+  static void Write(Message* m, const param_type& p) {
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    return true;
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+  }
+};
+
+template <class A>
+struct ParamTraits< Tuple1<A> > {
+  typedef Tuple1<A> param_type;
+  static void Write(Message* m, const param_type& p) {
+    WriteParam(m, p.a);
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    return ReadParam(m, iter, &r->a);
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    LogParam(p.a, l);
+  }
+};
+
+template <class A, class B>
+struct ParamTraits< Tuple2<A, B> > {
+  typedef Tuple2<A, B> param_type;
+  static void Write(Message* m, const param_type& p) {
+    WriteParam(m, p.a);
+    WriteParam(m, p.b);
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    return (ReadParam(m, iter, &r->a) &&
+            ReadParam(m, iter, &r->b));
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    LogParam(p.a, l);
+    l->append(L", ");
+    LogParam(p.b, l);
+  }
+};
+
+template <class A, class B, class C>
+struct ParamTraits< Tuple3<A, B, C> > {
+  typedef Tuple3<A, B, C> param_type;
+  static void Write(Message* m, const param_type& p) {
+    WriteParam(m, p.a);
+    WriteParam(m, p.b);
+    WriteParam(m, p.c);
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    return (ReadParam(m, iter, &r->a) &&
+            ReadParam(m, iter, &r->b) &&
+            ReadParam(m, iter, &r->c));
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    LogParam(p.a, l);
+    l->append(L", ");
+    LogParam(p.b, l);
+    l->append(L", ");
+    LogParam(p.c, l);
+  }
+};
+
+template <class A, class B, class C, class D>
+struct ParamTraits< Tuple4<A, B, C, D> > {
+  typedef Tuple4<A, B, C, D> param_type;
+  static void Write(Message* m, const param_type& p) {
+    WriteParam(m, p.a);
+    WriteParam(m, p.b);
+    WriteParam(m, p.c);
+    WriteParam(m, p.d);
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    return (ReadParam(m, iter, &r->a) &&
+            ReadParam(m, iter, &r->b) &&
+            ReadParam(m, iter, &r->c) &&
+            ReadParam(m, iter, &r->d));
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    LogParam(p.a, l);
+    l->append(L", ");
+    LogParam(p.b, l);
+    l->append(L", ");
+    LogParam(p.c, l);
+    l->append(L", ");
+    LogParam(p.d, l);
+  }
+};
+
+template <class A, class B, class C, class D, class E>
+struct ParamTraits< Tuple5<A, B, C, D, E> > {
+  typedef Tuple5<A, B, C, D, E> param_type;
+  static void Write(Message* m, const param_type& p) {
+    WriteParam(m, p.a);
+    WriteParam(m, p.b);
+    WriteParam(m, p.c);
+    WriteParam(m, p.d);
+    WriteParam(m, p.e);
+  }
+  static bool Read(const Message* m, void** iter, param_type* r) {
+    return (ReadParam(m, iter, &r->a) &&
+            ReadParam(m, iter, &r->b) &&
+            ReadParam(m, iter, &r->c) &&
+            ReadParam(m, iter, &r->d) &&
+            ReadParam(m, iter, &r->e));
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    LogParam(p.a, l);
+    l->append(L", ");
+    LogParam(p.b, l);
+    l->append(L", ");
+    LogParam(p.c, l);
+    l->append(L", ");
+    LogParam(p.d, l);
+    l->append(L", ");
+    LogParam(p.e, l);
+  }
+};
+
+//-----------------------------------------------------------------------------
+// Generic message subclasses
+
+// Used for asynchronous messages.
+template <class ParamType>
+class MessageWithTuple : public Message {
+ public:
+  typedef ParamType Param;
+  typedef typename ParamType::ParamTuple RefParam;
+
+  MessageWithTuple(int32 routing_id, uint16 type, const RefParam& p)
+      : Message(routing_id, type, PRIORITY_NORMAL) {
+    WriteParam(this, p);
+  }
+
+  static bool Read(const Message* msg, Param* p) {
+    void* iter = NULL;
+    if (ReadParam(msg, &iter, p))
+      return true;
+    NOTREACHED() << "Error deserializing message " << msg->type();
+    return false;
+  }
+
+  // Generic dispatcher.  Should cover most cases.
+  template<class T, class Method>
+  static bool Dispatch(const Message* msg, T* obj, Method func) {
+    Param p;
+    if (Read(msg, &p)) {
+      DispatchToMethod(obj, func, p);
+      return true;
+    }
+    return false;
+  }
+
+  // The following dispatchers exist for the case where the callback function
+  // needs the message as well.  They assume that "Param" is a type of Tuple
+  // (except the one arg case, as there is no Tuple1).
+  template<class T, typename TA>
+  static bool Dispatch(const Message* msg, T* obj,
+                       void (T::*func)(const Message&, TA)) {
+    Param p;
+    if (Read(msg, &p)) {
+      (obj->*func)(*msg, p.a);
+      return true;
+    }
+    return false;
+  }
+
+  template<class T, typename TA, typename TB>
+  static bool Dispatch(const Message* msg, T* obj,
+                       void (T::*func)(const Message&, TA, TB)) {
+    Param p;
+    if (Read(msg, &p)) {
+      (obj->*func)(*msg, p.a, p.b);
+      return true;
+    }
+    return false;
+  }
+
+  template<class T, typename TA, typename TB, typename TC>
+  static bool Dispatch(const Message* msg, T* obj,
+                       void (T::*func)(const Message&, TA, TB, TC)) {
+    Param p;
+    if (Read(msg, &p)) {
+      (obj->*func)(*msg, p.a, p.b, p.c);
+      return true;
+    }
+    return false;
+  }
+
+  template<class T, typename TA, typename TB, typename TC, typename TD>
+  static bool Dispatch(const Message* msg, T* obj,
+                       void (T::*func)(const Message&, TA, TB, TC, TD)) {
+    Param p;
+    if (Read(msg, &p)) {
+      (obj->*func)(*msg, p.a, p.b, p.c, p.d);
+      return true;
+    }
+    return false;
+  }
+
+  template<class T, typename TA, typename TB, typename TC, typename TD,
+           typename TE>
+  static bool Dispatch(const Message* msg, T* obj,
+                       void (T::*func)(const Message&, TA, TB, TC, TD, TE)) {
+    Param p;
+    if (Read(msg, &p)) {
+      (obj->*func)(*msg, p.a, p.b, p.c, p.d, p.e);
+      return true;
+    }
+    return false;
+  }
+
+  static void Log(const Message* msg, std::wstring* l) {
+    Param p;
+    if (Read(msg, &p))
+      LogParam(p, l);
+  }
+
+  // Functions used to do manual unpacking.  Only used by the automation code,
+  // these should go away once that code uses SyncChannel.
+  template<typename TA, typename TB>
+  static bool Read(const IPC::Message* msg, TA* a, TB* b) {
+    ParamType params;
+    if (!Read(msg, &params))
+      return false;
+    *a = params.a;
+    *b = params.b;
+    return true;
+  }
+
+  template<typename TA, typename TB, typename TC>
+  static bool Read(const IPC::Message* msg, TA* a, TB* b, TC* c) {
+    ParamType params;
+    if (!Read(msg, &params))
+      return false;
+    *a = params.a;
+    *b = params.b;
+    *c = params.c;
+    return true;
+  }
+
+  template<typename TA, typename TB, typename TC, typename TD>
+  static bool Read(const IPC::Message* msg, TA* a, TB* b, TC* c, TD* d) {
+    ParamType params;
+    if (!Read(msg, &params))
+      return false;
+    *a = params.a;
+    *b = params.b;
+    *c = params.c;
+    *d = params.d;
+    return true;
+  }
+
+  template<typename TA, typename TB, typename TC, typename TD, typename TE>
+  static bool Read(const IPC::Message* msg, TA* a, TB* b, TC* c, TD* d, TE* e) {
+    ParamType params;
+    if (!Read(msg, &params))
+      return false;
+    *a = params.a;
+    *b = params.b;
+    *c = params.c;
+    *d = params.d;
+    *e = params.e;
+    return true;
+  }
+};
+
+// This class assumes that its template argument is a RefTuple (a Tuple with
+// reference elements).
+template <class RefTuple>
+class ParamDeserializer : public MessageReplyDeserializer {
+ public:
+  explicit ParamDeserializer(const RefTuple& out) : out_(out) { }
+
+  bool SerializeOutputParameters(const IPC::Message& msg, void* iter) {
+    return ReadParam(&msg, &iter, &out_);
+  }
+
+  RefTuple out_;
+};
+
+// defined in ipc_logging.cc
+void GenerateLogData(const std::string& channel, const Message& message,
+                     LogData* data);
+
+// Used for synchronous messages.
+template <class SendParamType, class ReplyParamType>
+class MessageWithReply : public SyncMessage {
+ public:
+  typedef SendParamType SendParam;
+  typedef typename SendParam::ParamTuple RefSendParam;
+  typedef ReplyParamType ReplyParam;
+
+  MessageWithReply(int32 routing_id, uint16 type,
+                   const RefSendParam& send, const ReplyParam& reply)
+      : SyncMessage(routing_id, type, PRIORITY_NORMAL,
+                    new ParamDeserializer<ReplyParam>(reply)) {
+    WriteParam(this, send);
+  }
+
+  static void Log(const Message* msg, std::wstring* l) {
+    if (msg->is_sync()) {
+      SendParam p;
+      void* iter = SyncMessage::GetDataIterator(msg);
+      if (ReadParam(msg, &iter, &p))
+        LogParam(p, l);
+
+#if defined(IPC_MESSAGE_LOG_ENABLED)
+      const std::wstring& output_params = msg->output_params();
+      if (!l->empty() && !output_params.empty())
+        l->append(L", ");
+
+      l->append(output_params);
+#endif
+    } else {
+      // This is an outgoing reply.  Now that we have the output parameters, we
+      // can finally log the message.
+      typename ReplyParam::ValueTuple p;
+      void* iter = SyncMessage::GetDataIterator(msg);
+      if (ReadParam(msg, &iter, &p))
+        LogParam(p, l);
+    }
+  }
+
+  template<class T, class Method>
+  static bool Dispatch(const Message* msg, T* obj, Method func) {
+    SendParam send_params;
+    void* iter = GetDataIterator(msg);
+    Message* reply = GenerateReply(msg);
+    bool error;
+    if (ReadParam(msg, &iter, &send_params)) {
+      typename ReplyParam::ValueTuple reply_params;
+      DispatchToMethod(obj, func, send_params, &reply_params);
+      WriteParam(reply, reply_params);
+      error = false;
+#ifdef IPC_MESSAGE_LOG_ENABLED
+      if (msg->received_time() != 0) {
+        std::wstring output_params;
+        LogParam(reply_params, &output_params);
+        msg->set_output_params(output_params);
+      }
+#endif
+    } else {
+      NOTREACHED() << "Error deserializing message " << msg->type();
+      reply->set_reply_error();
+      error = true;
+    }
+
+    obj->Send(reply);
+    return !error;
+  }
+
+  template<class T, class Method>
+  static bool DispatchDelayReply(const Message* msg, T* obj, Method func) {
+    SendParam send_params;
+    void* iter = GetDataIterator(msg);
+    Message* reply = GenerateReply(msg);
+    bool error;
+    if (ReadParam(msg, &iter, &send_params)) {
+      Tuple1<Message&> t = MakeRefTuple(*reply);
+
+#ifdef IPC_MESSAGE_LOG_ENABLED
+      if (msg->sent_time()) {
+        // Don't log the sync message after dispatch, as we don't have the
+        // output parameters at that point.  Instead, save its data and log it
+        // with the outgoing reply message when it's sent.
+        LogData* data = new LogData;
+        GenerateLogData("", *msg, data);
+        msg->set_dont_log();
+        reply->set_sync_log_data(data);
+      }
+#endif
+      DispatchToMethod(obj, func, send_params, &t);
+      error = false;
+    } else {
+      NOTREACHED() << "Error deserializing message " << msg->type();
+      reply->set_reply_error();
+      obj->Send(reply);
+      error = true;
+    }
+    return !error;
+  }
+
+  template<typename TA>
+  static void WriteReplyParams(Message* reply, TA a) {
+    ReplyParam p(a);
+    WriteParam(reply, p);
+  }
+
+  template<typename TA, typename TB>
+  static void WriteReplyParams(Message* reply, TA a, TB b) {
+    ReplyParam p(a, b);
+    WriteParam(reply, p);
+  }
+
+  template<typename TA, typename TB, typename TC>
+  static void WriteReplyParams(Message* reply, TA a, TB b, TC c) {
+    ReplyParam p(a, b, c);
+    WriteParam(reply, p);
+  }
+
+  template<typename TA, typename TB, typename TC, typename TD>
+  static void WriteReplyParams(Message* reply, TA a, TB b, TC c, TD d) {
+    ReplyParam p(a, b, c, d);
+    WriteParam(reply, p);
+  }
+
+  template<typename TA, typename TB, typename TC, typename TD, typename TE>
+  static void WriteReplyParams(Message* reply, TA a, TB b, TC c, TD d, TE e) {
+    ReplyParam p(a, b, c, d, e);
+    WriteParam(reply, p);
+  }
+};
+
+//-----------------------------------------------------------------------------
+
+}  // namespace IPC
+
+#endif  // IPC_IPC_MESSAGE_UTILS_H_