1// Copyright 2006-2009 the V8 project authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef V8_LOG_UTILS_H_
6#define V8_LOG_UTILS_H_
7
8#include <stdio.h>
9
10#include <cstdarg>
11
12#include "src/allocation.h"
13#include "src/base/compiler-specific.h"
14#include "src/base/optional.h"
15#include "src/base/platform/mutex.h"
16#include "src/flags.h"
17#include "src/ostreams.h"
18
19namespace v8 {
20namespace internal {
21
22class Logger;
23template <typename T>
24class Vector;
25
26enum class LogSeparator { kSeparator };
27
28// Functions and data for performing output of log messages.
29class Log {
30 public:
31 Log(Logger* log, const char* log_file_name);
32 // Disables logging, but preserves acquired resources.
33 void stop() { is_stopped_ = true; }
34
35 static bool InitLogAtStart() {
36 return FLAG_log || FLAG_log_api || FLAG_log_code || FLAG_log_handles ||
37 FLAG_log_suspect || FLAG_ll_prof || FLAG_perf_basic_prof ||
38 FLAG_perf_prof || FLAG_log_source_code || FLAG_gdbjit ||
39 FLAG_log_internal_timer_events || FLAG_prof_cpp || FLAG_trace_ic ||
40 FLAG_log_function_events;
41 }
42
43 // Frees all resources acquired in Initialize and Open... functions.
44 // When a temporary file is used for the log, returns its stream descriptor,
45 // leaving the file open.
46 FILE* Close();
47
48 // Returns whether logging is enabled.
49 bool IsEnabled() { return !is_stopped_ && output_handle_ != nullptr; }
50
51 // Size of buffer used for formatting log messages.
52 static const int kMessageBufferSize = 2048;
53
54 // This mode is only used in tests, as temporary files are automatically
55 // deleted on close and thus can't be accessed afterwards.
56 V8_EXPORT_PRIVATE static const char* const kLogToTemporaryFile;
57 static const char* const kLogToConsole;
58
59 // Utility class for formatting log messages. It escapes the given messages
60 // and then appends them to the static buffer in Log.
61 class MessageBuilder {
62 public:
63 // Create a message builder starting from position 0.
64 // This acquires the mutex in the log as well.
65 explicit MessageBuilder(Log* log);
66 ~MessageBuilder() = default;
67
68 void AppendString(String str,
69 base::Optional<int> length_limit = base::nullopt);
70 void AppendString(Vector<const char> str);
71 void AppendString(const char* str);
72 void AppendString(const char* str, size_t length);
73 void PRINTF_FORMAT(2, 3) AppendFormatString(const char* format, ...);
74 void AppendCharacter(char c);
75 void AppendSymbolName(Symbol symbol);
76
77 // Delegate insertion to the underlying {log_}.
78 // All appended strings are escaped to maintain one-line log entries.
79 template <typename T>
80 MessageBuilder& operator<<(T value) {
81 log_->os_ << value;
82 return *this;
83 }
84
85 // Finish the current log line an flush the it to the log file.
86 void WriteToLogFile();
87
88 private:
89 // Prints the format string into |log_->format_buffer_|. Returns the length
90 // of the result, or kMessageBufferSize if it was truncated.
91 int PRINTF_FORMAT(2, 0)
92 FormatStringIntoBuffer(const char* format, va_list args);
93
94 void AppendSymbolNameDetails(String str, bool show_impl_info);
95
96 void PRINTF_FORMAT(2, 3) AppendRawFormatString(const char* format, ...);
97 void AppendRawCharacter(const char character);
98
99 Log* log_;
100 base::MutexGuard lock_guard_;
101 };
102
103 private:
104 static FILE* CreateOutputHandle(const char* file_name);
105
106 // Implementation of writing to a log file.
107 int WriteToFile(const char* msg, int length) {
108 DCHECK_NOT_NULL(output_handle_);
109 os_.write(msg, length);
110 DCHECK(!os_.bad());
111 return length;
112 }
113
114 // Whether logging is stopped (e.g. due to insufficient resources).
115 bool is_stopped_;
116
117 // When logging is active output_handle_ is used to store a pointer to log
118 // destination. mutex_ should be acquired before using output_handle_.
119 FILE* output_handle_;
120 OFStream os_;
121
122 // mutex_ is a Mutex used for enforcing exclusive
123 // access to the formatting buffer and the log file or log memory buffer.
124 base::Mutex mutex_;
125
126 // Buffer used for formatting log messages. This is a singleton buffer and
127 // mutex_ should be acquired before using it.
128 char* format_buffer_;
129
130 Logger* logger_;
131
132 friend class Logger;
133};
134
135template <>
136Log::MessageBuilder& Log::MessageBuilder::operator<<<LogSeparator>(
137 LogSeparator separator);
138template <>
139Log::MessageBuilder& Log::MessageBuilder::operator<<<void*>(void* pointer);
140template <>
141Log::MessageBuilder& Log::MessageBuilder::operator<<<const char*>(
142 const char* string);
143template <>
144Log::MessageBuilder& Log::MessageBuilder::operator<<<char>(char c);
145template <>
146Log::MessageBuilder& Log::MessageBuilder::operator<<<String>(String string);
147template <>
148Log::MessageBuilder& Log::MessageBuilder::operator<<<Symbol>(Symbol symbol);
149template <>
150Log::MessageBuilder& Log::MessageBuilder::operator<<<Name>(Name name);
151
152} // namespace internal
153} // namespace v8
154
155#endif // V8_LOG_UTILS_H_
156