1 // Copyright 2019 The Chromium 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 UTIL_TRACE_LOGGING_H_
6 #define UTIL_TRACE_LOGGING_H_
7
8 #include "platform/base/trace_logging_types.h"
9
10 // All compile-time macros for tracing.
11 // NOTE: The ternary operator is used here to ensure that the TraceLogger object
12 // is only constructed if tracing is enabled, but at the same time is created in
13 // the caller's scope. The C++ standards guide guarantees that the constructor
14 // should only be called when IsTraceLoggingEnabled(...) evaluates to true.
15 // static_cast calls are used because if the type of the result of the ternary
16 // operator does not match the expected type, temporary storage is used for the
17 // created object, which results in an extra call to the constructor and
18 // destructor of the tracing objects.
19 //
20 // Further details about how these macros are used can be found in
21 // docs/trace_logging.md.
22 // TODO(rwkeane): Add support for user-provided properties.
23
24 #if defined(ENABLE_TRACE_LOGGING)
25
26 #define INCLUDING_FROM_UTIL_TRACE_LOGGING_H_
27 #include "util/trace_logging/macro_support.h"
28 #undef INCLUDING_FROM_UTIL_TRACE_LOGGING_H_
29
30 #define TRACE_SET_RESULT(result) \
31 do { \
32 if (TRACE_IS_ENABLED(openscreen::TraceCategory::Value::kAny)) { \
33 openscreen::internal::ScopedTraceOperation::set_result(result); \
34 } \
35 } while (false)
36 #define TRACE_SET_HIERARCHY(ids) TRACE_SET_HIERARCHY_INTERNAL(__LINE__, ids)
37 #define TRACE_HIERARCHY \
38 (TRACE_IS_ENABLED(openscreen::TraceCategory::Value::kAny) \
39 ? openscreen::internal::ScopedTraceOperation::hierarchy() \
40 : openscreen::TraceIdHierarchy::Empty())
41 #define TRACE_CURRENT_ID \
42 (TRACE_IS_ENABLED(openscreen::TraceCategory::Value::kAny) \
43 ? openscreen::internal::ScopedTraceOperation::current_id() \
44 : kEmptyTraceId)
45 #define TRACE_ROOT_ID \
46 (TRACE_IS_ENABLED(openscreen::TraceCategory::Value::kAny) \
47 ? openscreen::internal::ScopedTraceOperation::root_id() \
48 : kEmptyTraceId)
49
50 // Synchronous Trace Macros.
51 #define TRACE_SCOPED(category, name, ...) \
52 TRACE_SCOPED_INTERNAL(__LINE__, category, name, ##__VA_ARGS__)
53 #define TRACE_DEFAULT_SCOPED(category, ...) \
54 TRACE_SCOPED(category, __PRETTY_FUNCTION__, ##__VA_ARGS__)
55
56 // Asynchronous Trace Macros.
57 #define TRACE_ASYNC_START(category, name, ...) \
58 TRACE_ASYNC_START_INTERNAL(__LINE__, category, name, ##__VA_ARGS__)
59
60 #define TRACE_ASYNC_END(category, id, result) \
61 TRACE_IS_ENABLED(category) \
62 ? openscreen::internal::ScopedTraceOperation::TraceAsyncEnd( \
63 __LINE__, __FILE__, id, result) \
64 : false
65
66 #else // ENABLE_TRACE_LOGGING not defined
67
68 namespace openscreen {
69 namespace internal {
70 // Consumes |args| (to avoid "warn unused variable" errors at compile time), and
71 // provides a "void" result type in the macros below.
72 template <typename... Args>
DoNothingForTracing(Args...args)73 inline void DoNothingForTracing(Args... args) {}
74 } // namespace internal
75 } // namespace openscreen
76
77 #define TRACE_SET_RESULT(result) \
78 openscreen::internal::DoNothingForTracing(result)
79 #define TRACE_SET_HIERARCHY(ids) openscreen::internal::DoNothingForTracing(ids)
80 #define TRACE_HIERARCHY openscreen::TraceIdHierarchy::Empty()
81 #define TRACE_CURRENT_ID openscreen::kEmptyTraceId
82 #define TRACE_ROOT_ID openscreen::kEmptyTraceId
83 #define TRACE_SCOPED(category, name, ...) \
84 openscreen::internal::DoNothingForTracing(category, name, ##__VA_ARGS__)
85 #define TRACE_DEFAULT_SCOPED(category, ...) \
86 TRACE_SCOPED(category, __PRETTY_FUNCTION__, ##__VA_ARGS__)
87 #define TRACE_ASYNC_START(category, name, ...) \
88 openscreen::internal::DoNothingForTracing(category, name, ##__VA_ARGS__)
89 #define TRACE_ASYNC_END(category, id, result) \
90 openscreen::internal::DoNothingForTracing(category, id, result)
91
92 #endif // defined(ENABLE_TRACE_LOGGING)
93
94 #endif // UTIL_TRACE_LOGGING_H_
95