1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
|
// Copyright 2019 the V8 project 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 "src/libplatform/tracing/json-trace-event-listener.h"
#include <cmath>
#include "base/trace_event/common/trace_event_common.h"
#include "perfetto/trace/chrome/chrome_trace_packet.pb.h"
#include "perfetto/trace/trace.pb.h"
#include "perfetto/tracing.h"
#include "src/base/logging.h"
#include "src/base/macros.h"
namespace v8 {
namespace platform {
namespace tracing {
JSONTraceEventListener::JSONTraceEventListener(std::ostream* stream)
: stream_(stream) {
*stream_ << "{\"traceEvents\":[";
}
JSONTraceEventListener::~JSONTraceEventListener() { *stream_ << "]}"; }
// TODO(petermarshall): Clean up this code which was copied from trace-writer.cc
// once we've removed that file.
// Writes the given string, taking care to escape characters when necessary.
void JSONTraceEventListener::AppendJSONString(const char* str) {
size_t len = strlen(str);
*stream_ << "\"";
for (size_t i = 0; i < len; ++i) {
// All of the permitted escape sequences in JSON strings, as per
// https://mathiasbynens.be/notes/javascript-escapes
switch (str[i]) {
case '\b':
*stream_ << "\\b";
break;
case '\f':
*stream_ << "\\f";
break;
case '\n':
*stream_ << "\\n";
break;
case '\r':
*stream_ << "\\r";
break;
case '\t':
*stream_ << "\\t";
break;
case '\"':
*stream_ << "\\\"";
break;
case '\\':
*stream_ << "\\\\";
break;
// Note that because we use double quotes for JSON strings,
// we don't need to escape single quotes.
default:
*stream_ << str[i];
break;
}
}
*stream_ << "\"";
}
void JSONTraceEventListener::AppendArgValue(
const ::perfetto::protos::ChromeTraceEvent_Arg& arg) {
if (arg.has_bool_value()) {
*stream_ << (arg.bool_value() ? "true" : "false");
} else if (arg.has_uint_value()) {
*stream_ << arg.uint_value();
} else if (arg.has_int_value()) {
*stream_ << arg.int_value();
} else if (arg.has_double_value()) {
std::string real;
double val = arg.double_value();
if (std::isfinite(val)) {
std::ostringstream convert_stream;
convert_stream << val;
real = convert_stream.str();
// Ensure that the number has a .0 if there's no decimal or 'e'. This
// makes sure that when we read the JSON back, it's interpreted as a
// real rather than an int.
if (real.find('.') == std::string::npos &&
real.find('e') == std::string::npos &&
real.find('E') == std::string::npos) {
real += ".0";
}
} else if (std::isnan(val)) {
// The JSON spec doesn't allow NaN and Infinity (since these are
// objects in EcmaScript). Use strings instead.
real = "\"NaN\"";
} else if (val < 0) {
real = "\"-Infinity\"";
} else {
real = "\"Infinity\"";
}
*stream_ << real;
} else if (arg.has_string_value()) {
AppendJSONString(arg.string_value().c_str());
} else if (arg.has_pointer_value()) {
// JSON only supports double and int numbers.
// So as not to lose bits from a 64-bit pointer, output as a hex string.
*stream_ << "\"0x" << std::hex << arg.pointer_value() << std::dec << "\"";
} else if (arg.has_json_value()) {
*stream_ << arg.json_value();
}
// V8 does not emit proto arguments currently.
CHECK(!arg.has_traced_value());
}
void JSONTraceEventListener::ProcessPacket(
const ::perfetto::protos::TracePacket& packet) {
for (const ::perfetto::protos::ChromeTraceEvent& event :
packet.chrome_events().trace_events()) {
if (append_comma_) *stream_ << ",";
append_comma_ = true;
// TODO(petermarshall): Handle int64 fields differently?
// clang-format off
*stream_ << "{\"pid\":" << event.process_id()
<< ",\"tid\":" << event.thread_id()
<< ",\"ts\":" << event.timestamp()
<< ",\"tts\":" << event.thread_timestamp()
<< ",\"ph\":\"" << static_cast<char>(event.phase())
<< "\",\"cat\":\"" << event.category_group_name()
<< "\",\"name\":\"" << event.name()
<< "\",\"dur\":" << event.duration()
<< ",\"tdur\":" << event.thread_duration();
// clang-format on
if (event.flags() &
(TRACE_EVENT_FLAG_FLOW_IN | TRACE_EVENT_FLAG_FLOW_OUT)) {
*stream_ << ",\"bind_id\":\"0x" << std::hex << event.bind_id() << "\""
<< std::dec;
if (event.flags() & TRACE_EVENT_FLAG_FLOW_IN) {
*stream_ << ",\"flow_in\":true";
}
if (event.flags() & TRACE_EVENT_FLAG_FLOW_OUT) {
*stream_ << ",\"flow_out\":true";
}
}
if (event.flags() & TRACE_EVENT_FLAG_HAS_ID) {
if (event.has_scope()) {
*stream_ << ",\"scope\":\"" << event.scope() << "\"";
}
// So as not to lose bits from a 64-bit integer, output as a hex string.
*stream_ << ",\"id\":\"0x" << std::hex << event.id() << "\"" << std::dec;
}
*stream_ << ",\"args\":{";
int i = 0;
for (const ::perfetto::protos::ChromeTraceEvent_Arg& arg : event.args()) {
if (i++ > 0) *stream_ << ",";
*stream_ << "\"" << arg.name() << "\":";
AppendArgValue(arg);
}
*stream_ << "}}";
}
}
} // namespace tracing
} // namespace platform
} // namespace v8
|
