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// Copyright 2021 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef BASE_TRACE_EVENT_TRACED_VALUE_SUPPORT_H_
#define BASE_TRACE_EVENT_TRACED_VALUE_SUPPORT_H_
#include "base/memory/raw_ptr.h"
#include "base/memory/raw_ref.h"
#include "base/memory/scoped_refptr.h"
#include "base/memory/weak_ptr.h"
#include "base/strings/string_piece.h"
#include "base/strings/utf_string_conversions.h"
#include "base/time/time.h"
#include "base/unguessable_token.h"
#include "third_party/abseil-cpp/absl/types/optional.h"
#include "third_party/perfetto/include/perfetto/tracing/traced_proto.h"
#include "third_party/perfetto/include/perfetto/tracing/traced_value.h"
// This file contains specialisations for trace serialisation for key
// widely-used //base classes. As these specialisations require full definition
// of perfetto::TracedValue and almost every source unit in Chromium requires
// one of these //base concepts, include specialiazations here and expose them
// to the users including trace_event.h, rather than adding a dependency from
// scoped_refptr.h et al on traced_value.h.
namespace perfetto {
// If T is serialisable into a trace, scoped_refptr<T> is serialisable as well.
template <class T>
struct TraceFormatTraits<scoped_refptr<T>,
perfetto::check_traced_value_support_t<T>> {
static void WriteIntoTrace(perfetto::TracedValue context,
const scoped_refptr<T>& value) {
if (!value) {
std::move(context).WritePointer(nullptr);
return;
}
perfetto::WriteIntoTracedValue(std::move(context), *value);
}
template <class MessageType>
static void WriteIntoTrace(perfetto::TracedProto<MessageType> context,
const scoped_refptr<T>& value) {
if (value) {
// Proto message without any fields is treated as nullptr.
return;
}
perfetto::WriteIntoTracedProto(std::move(context), *value);
}
};
// If T is serialisable into a trace, base::WeakPtr<T> is serialisable as well.
template <class T>
struct TraceFormatTraits<::base::WeakPtr<T>,
perfetto::check_traced_value_support_t<T>> {
static void WriteIntoTrace(perfetto::TracedValue context,
const ::base::WeakPtr<T>& value) {
if (!value) {
std::move(context).WritePointer(nullptr);
return;
}
perfetto::WriteIntoTracedValue(std::move(context), *value);
}
};
// If T is serialisable into a trace, absl::optional<T> is serialisable as well.
// Note that we need definitions for both absl::optional<T>& and
// const absl::optional<T>& (unlike scoped_refptr and WeakPtr above), as
// dereferencing const scoped_refptr<T>& gives you T, while dereferencing const
// absl::optional<T>& gives you const T&.
template <class T>
struct TraceFormatTraits<::absl::optional<T>,
perfetto::check_traced_value_support_t<T>> {
static void WriteIntoTrace(perfetto::TracedValue context,
const ::absl::optional<T>& value) {
if (!value) {
std::move(context).WritePointer(nullptr);
return;
}
perfetto::WriteIntoTracedValue(std::move(context), *value);
}
static void WriteIntoTrace(perfetto::TracedValue context,
::absl::optional<T>& value) {
if (!value) {
std::move(context).WritePointer(nullptr);
return;
}
perfetto::WriteIntoTracedValue(std::move(context), *value);
}
};
// If T is serialisable into a trace, raw_ptr<T> is serialisable as well.
template <class T>
struct TraceFormatTraits<::base::raw_ptr<T>,
perfetto::check_traced_value_support_t<T>> {
static void WriteIntoTrace(perfetto::TracedValue context,
const ::base::raw_ptr<T>& value) {
if (!value) {
std::move(context).WritePointer(nullptr);
return;
}
perfetto::WriteIntoTracedValue(std::move(context), *value);
}
static void WriteIntoTrace(perfetto::TracedValue context,
::base::raw_ptr<T>& value) {
if (!value) {
std::move(context).WritePointer(nullptr);
return;
}
perfetto::WriteIntoTracedValue(std::move(context), *value);
}
};
// If T is serialisable into a trace, raw_ref<T> is serialisable as well.
template <class T>
struct TraceFormatTraits<::base::raw_ref<T>,
perfetto::check_traced_value_support_t<T>> {
static void WriteIntoTrace(perfetto::TracedValue context,
const ::base::raw_ref<T>& value) {
if (!value) {
std::move(context).WritePointer(nullptr);
return;
}
perfetto::WriteIntoTracedValue(std::move(context), *value);
}
static void WriteIntoTrace(perfetto::TracedValue context,
::base::raw_ref<T>& value) {
if (!value) {
std::move(context).WritePointer(nullptr);
return;
}
perfetto::WriteIntoTracedValue(std::move(context), *value);
}
};
// Time-related classes.
// TODO(altimin): Make them first-class primitives in TracedValue and Perfetto
// UI.
template <>
struct TraceFormatTraits<::base::TimeDelta> {
static void WriteIntoTrace(perfetto::TracedValue context,
const ::base::TimeDelta& value) {
std::move(context).WriteInt64(value.InMicroseconds());
}
};
template <>
struct TraceFormatTraits<::base::TimeTicks> {
static void WriteIntoTrace(perfetto::TracedValue context,
const ::base::TimeTicks& value) {
perfetto::WriteIntoTracedValue(std::move(context), value.since_origin());
}
};
template <>
struct TraceFormatTraits<::base::Time> {
static void WriteIntoTrace(perfetto::TracedValue context,
const ::base::Time& value) {
perfetto::WriteIntoTracedValue(std::move(context), value.since_origin());
}
};
// base::UnguessableToken.
// TODO(altimin): Add first-class primitive, which will allow to show a
// human-comprehensible alias for all unguessable tokens instead.
template <>
struct TraceFormatTraits<::base::UnguessableToken> {
static void WriteIntoTrace(perfetto::TracedValue context,
const ::base::UnguessableToken& value) {
return std::move(context).WriteString(value.ToString());
}
};
// UTF-16 string support.
template <>
struct TraceFormatTraits<std::u16string> {
static void WriteIntoTrace(perfetto::TracedValue context,
const std::u16string& value) {
return std::move(context).WriteString(::base::UTF16ToUTF8(value));
}
};
template <size_t N>
struct TraceFormatTraits<char16_t[N]> {
static void WriteIntoTrace(perfetto::TracedValue context,
const char16_t value[N]) {
return std::move(context).WriteString(
::base::UTF16ToUTF8(::base::StringPiece16(value)));
}
};
template <>
struct TraceFormatTraits<const char16_t*> {
static void WriteIntoTrace(perfetto::TracedValue context,
const char16_t* value) {
return std::move(context).WriteString(
::base::UTF16ToUTF8(::base::StringPiece16(value)));
}
};
// Wide string support.
template <>
struct TraceFormatTraits<std::wstring> {
static void WriteIntoTrace(perfetto::TracedValue context,
const std::wstring& value) {
return std::move(context).WriteString(::base::WideToUTF8(value));
}
};
template <size_t N>
struct TraceFormatTraits<wchar_t[N]> {
static void WriteIntoTrace(perfetto::TracedValue context,
const wchar_t value[N]) {
return std::move(context).WriteString(
::base::WideToUTF8(::base::WStringPiece(value)));
}
};
template <>
struct TraceFormatTraits<const wchar_t*> {
static void WriteIntoTrace(perfetto::TracedValue context,
const wchar_t* value) {
return std::move(context).WriteString(
::base::WideToUTF8(::base::WStringPiece(value)));
}
};
// base::StringPiece support.
template <>
struct TraceFormatTraits<::base::StringPiece> {
static void WriteIntoTrace(perfetto::TracedValue context,
::base::StringPiece value) {
return std::move(context).WriteString(value.data(), value.length());
}
};
template <>
struct TraceFormatTraits<::base::StringPiece16> {
static void WriteIntoTrace(perfetto::TracedValue context,
::base::StringPiece16 value) {
return std::move(context).WriteString(::base::UTF16ToUTF8(value));
}
};
template <>
struct TraceFormatTraits<::base::WStringPiece> {
static void WriteIntoTrace(perfetto::TracedValue context,
::base::WStringPiece value) {
return std::move(context).WriteString(::base::WideToUTF8(value));
}
};
} // namespace perfetto
#endif // BASE_TRACE_EVENT_TRACED_VALUE_SUPPORT_H_