summaryrefslogtreecommitdiff
path: root/absl/log/check.h
blob: 33145a57e9de19c2354645a61df438c8128f33a1 (plain)
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
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
// Copyright 2022 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// -----------------------------------------------------------------------------
// File: log/check.h
// -----------------------------------------------------------------------------
//
// This header declares a family of `CHECK` macros.
//
// `CHECK` macros terminate the program with a fatal error if the specified
// condition is not true.
//
// Except for those whose names begin with `DCHECK`, these macros are not
// controlled by `NDEBUG` (cf. `assert`), so the check will be executed
// regardless of compilation mode. `CHECK` and friends are thus useful for
// confirming invariants in situations where continuing to run would be worse
// than terminating, e.g., due to risk of data corruption or security
// compromise.  It is also more robust and portable to deliberately terminate
// at a particular place with a useful message and backtrace than to assume some
// ultimately unspecified and unreliable crashing behavior (such as a
// "segmentation fault").

#ifndef ABSL_LOG_CHECK_H_
#define ABSL_LOG_CHECK_H_

#include "absl/log/internal/check_impl.h"
#include "absl/log/internal/check_op.h"     // IWYU pragma: export
#include "absl/log/internal/conditions.h"   // IWYU pragma: export
#include "absl/log/internal/log_message.h"  // IWYU pragma: export
#include "absl/log/internal/strip.h"        // IWYU pragma: export

// CHECK()
//
// `CHECK` terminates the program with a fatal error if `condition` is not true.
//
// The message may include additional information such as stack traces, when
// available.
//
// Example:
//
//   CHECK(!cheese.empty()) << "Out of Cheese";
//
// Might produce a message like:
//
//   Check failed: !cheese.empty() Out of Cheese
#define CHECK(condition) ABSL_CHECK_IMPL((condition), #condition)

// QCHECK()
//
// `QCHECK` behaves like `CHECK` but does not print a full stack trace and does
// not run registered error handlers (as `QFATAL`).  It is useful when the
// problem is definitely unrelated to program flow, e.g. when validating user
// input.
#define QCHECK(condition) ABSL_QCHECK_IMPL((condition), #condition)

// PCHECK()
//
// `PCHECK` behaves like `CHECK` but appends a description of the current state
// of `errno` to the failure message.
//
// Example:
//
//   int fd = open("/var/empty/missing", O_RDONLY);
//   PCHECK(fd != -1) << "posix is difficult";
//
// Might produce a message like:
//
//   Check failed: fd != -1 posix is difficult: No such file or directory [2]
#define PCHECK(condition) ABSL_PCHECK_IMPL((condition), #condition)

// DCHECK()
//
// `DCHECK` behaves like `CHECK` in debug mode and does nothing otherwise (as
// `DLOG`).  Unlike with `CHECK` (but as with `assert`), it is not safe to rely
// on evaluation of `condition`: when `NDEBUG` is enabled, DCHECK does not
// evaluate the condition.
#define DCHECK(condition) ABSL_DCHECK_IMPL((condition), #condition)

// `CHECK_EQ` and friends are syntactic sugar for `CHECK(x == y)` that
// automatically output the expression being tested and the evaluated values on
// either side.
//
// Example:
//
//   int x = 3, y = 5;
//   CHECK_EQ(2 * x, y) << "oops!";
//
// Might produce a message like:
//
//   Check failed: 2 * x == y (6 vs. 5) oops!
//
// The values must implement the appropriate comparison operator as well as
// `operator<<(std::ostream&, ...)`.  Care is taken to ensure that each
// argument is evaluated exactly once, and that anything which is legal to pass
// as a function argument is legal here.  In particular, the arguments may be
// temporary expressions which will end up being destroyed at the end of the
// statement,
//
// Example:
//
//   CHECK_EQ(std::string("abc")[1], 'b');
//
// WARNING: Passing `NULL` as an argument to `CHECK_EQ` and similar macros does
// not compile.  Use `nullptr` instead.
#define CHECK_EQ(val1, val2) ABSL_CHECK_EQ_IMPL((val1), #val1, (val2), #val2)
#define CHECK_NE(val1, val2) ABSL_CHECK_NE_IMPL((val1), #val1, (val2), #val2)
#define CHECK_LE(val1, val2) ABSL_CHECK_LE_IMPL((val1), #val1, (val2), #val2)
#define CHECK_LT(val1, val2) ABSL_CHECK_LT_IMPL((val1), #val1, (val2), #val2)
#define CHECK_GE(val1, val2) ABSL_CHECK_GE_IMPL((val1), #val1, (val2), #val2)
#define CHECK_GT(val1, val2) ABSL_CHECK_GT_IMPL((val1), #val1, (val2), #val2)
#define QCHECK_EQ(val1, val2) ABSL_QCHECK_EQ_IMPL((val1), #val1, (val2), #val2)
#define QCHECK_NE(val1, val2) ABSL_QCHECK_NE_IMPL((val1), #val1, (val2), #val2)
#define QCHECK_LE(val1, val2) ABSL_QCHECK_LE_IMPL((val1), #val1, (val2), #val2)
#define QCHECK_LT(val1, val2) ABSL_QCHECK_LT_IMPL((val1), #val1, (val2), #val2)
#define QCHECK_GE(val1, val2) ABSL_QCHECK_GE_IMPL((val1), #val1, (val2), #val2)
#define QCHECK_GT(val1, val2) ABSL_QCHECK_GT_IMPL((val1), #val1, (val2), #val2)
#define DCHECK_EQ(val1, val2) ABSL_DCHECK_EQ_IMPL((val1), #val1, (val2), #val2)
#define DCHECK_NE(val1, val2) ABSL_DCHECK_NE_IMPL((val1), #val1, (val2), #val2)
#define DCHECK_LE(val1, val2) ABSL_DCHECK_LE_IMPL((val1), #val1, (val2), #val2)
#define DCHECK_LT(val1, val2) ABSL_DCHECK_LT_IMPL((val1), #val1, (val2), #val2)
#define DCHECK_GE(val1, val2) ABSL_DCHECK_GE_IMPL((val1), #val1, (val2), #val2)
#define DCHECK_GT(val1, val2) ABSL_DCHECK_GT_IMPL((val1), #val1, (val2), #val2)

// `CHECK_OK` and friends validate that the provided `absl::Status` or
// `absl::StatusOr<T>` is OK.  If it isn't, they print a failure message that
// includes the actual status and terminate the program.
//
// As with all `DCHECK` variants, `DCHECK_OK` has no effect (not even
// evaluating its argument) if `NDEBUG` is enabled.
//
// Example:
//
//   CHECK_OK(FunctionReturnsStatus(x, y, z)) << "oops!";
//
// Might produce a message like:
//
//   Check failed: FunctionReturnsStatus(x, y, z) is OK (ABORTED: timeout) oops!
#define CHECK_OK(status) ABSL_CHECK_OK_IMPL((status), #status)
#define QCHECK_OK(status) ABSL_QCHECK_OK_IMPL((status), #status)
#define DCHECK_OK(status) ABSL_DCHECK_OK_IMPL((status), #status)

// `CHECK_STREQ` and friends provide `CHECK_EQ` functionality for C strings,
// i.e., nul-terminated char arrays.  The `CASE` versions are case-insensitive.
//
// Example:
//
//   CHECK_STREQ(argv[0], "./skynet");
//
// Note that both arguments may be temporary strings which are destroyed by the
// compiler at the end of the current full expression.
//
// Example:
//
//   CHECK_STREQ(Foo().c_str(), Bar().c_str());
#define CHECK_STREQ(s1, s2) ABSL_CHECK_STREQ_IMPL((s1), #s1, (s2), #s2)
#define CHECK_STRNE(s1, s2) ABSL_CHECK_STRNE_IMPL((s1), #s1, (s2), #s2)
#define CHECK_STRCASEEQ(s1, s2) ABSL_CHECK_STRCASEEQ_IMPL((s1), #s1, (s2), #s2)
#define CHECK_STRCASENE(s1, s2) ABSL_CHECK_STRCASENE_IMPL((s1), #s1, (s2), #s2)
#define QCHECK_STREQ(s1, s2) ABSL_QCHECK_STREQ_IMPL((s1), #s1, (s2), #s2)
#define QCHECK_STRNE(s1, s2) ABSL_QCHECK_STRNE_IMPL((s1), #s1, (s2), #s2)
#define QCHECK_STRCASEEQ(s1, s2) \
  ABSL_QCHECK_STRCASEEQ_IMPL((s1), #s1, (s2), #s2)
#define QCHECK_STRCASENE(s1, s2) \
  ABSL_QCHECK_STRCASENE_IMPL((s1), #s1, (s2), #s2)
#define DCHECK_STREQ(s1, s2) ABSL_DCHECK_STREQ_IMPL((s1), #s1, (s2), #s2)
#define DCHECK_STRNE(s1, s2) ABSL_DCHECK_STRNE_IMPL((s1), #s1, (s2), #s2)
#define DCHECK_STRCASEEQ(s1, s2) \
  ABSL_DCHECK_STRCASEEQ_IMPL((s1), #s1, (s2), #s2)
#define DCHECK_STRCASENE(s1, s2) \
  ABSL_DCHECK_STRCASENE_IMPL((s1), #s1, (s2), #s2)

#endif  // ABSL_LOG_CHECK_H_