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Diffstat (limited to 'webrtc/rtc_base/checks.h')
| -rw-r--r-- | webrtc/rtc_base/checks.h | 485 |
1 files changed, 485 insertions, 0 deletions
diff --git a/webrtc/rtc_base/checks.h b/webrtc/rtc_base/checks.h new file mode 100644 index 0000000..61c074a --- /dev/null +++ b/webrtc/rtc_base/checks.h @@ -0,0 +1,485 @@ +/* + * Copyright 2006 The WebRTC 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 in the root of the source + * tree. An additional intellectual property rights grant can be found + * in the file PATENTS. All contributing project authors may + * be found in the AUTHORS file in the root of the source tree. + */ + +#ifndef RTC_BASE_CHECKS_H_ +#define RTC_BASE_CHECKS_H_ + +// If you for some reson need to know if DCHECKs are on, test the value of +// RTC_DCHECK_IS_ON. (Test its value, not if it's defined; it'll always be +// defined, to either a true or a false value.) +#if !defined(NDEBUG) || defined(DCHECK_ALWAYS_ON) +#define RTC_DCHECK_IS_ON 1 +#else +#define RTC_DCHECK_IS_ON 0 +#endif + +// Annotate a function that will not return control flow to the caller. +#if defined(_MSC_VER) +#define RTC_NORETURN __declspec(noreturn) +#elif defined(__GNUC__) +#define RTC_NORETURN __attribute__((__noreturn__)) +#else +#define RTC_NORETURN +#endif + +#ifdef __cplusplus +extern "C" { +#endif +RTC_NORETURN void rtc_FatalMessage(const char* file, int line, const char* msg); +#ifdef __cplusplus +} // extern "C" +#endif + +#ifdef RTC_DISABLE_CHECK_MSG +#define RTC_CHECK_MSG_ENABLED 0 +#else +#define RTC_CHECK_MSG_ENABLED 1 +#endif + +#if RTC_CHECK_MSG_ENABLED +#define RTC_CHECK_EVAL_MESSAGE(message) message +#else +#define RTC_CHECK_EVAL_MESSAGE(message) "" +#endif + +#ifdef __cplusplus +// C++ version. + +#include <string> + +#include "absl/meta/type_traits.h" +#include "absl/strings/string_view.h" +#include "rtc_base/numerics/safe_compare.h" +#include "rtc_base/system/inline.h" +#include "rtc_base/system/rtc_export.h" + +// The macros here print a message to stderr and abort under various +// conditions. All will accept additional stream messages. For example: +// RTC_DCHECK_EQ(foo, bar) << "I'm printed when foo != bar."; +// +// - RTC_CHECK(x) is an assertion that x is always true, and that if it isn't, +// it's better to terminate the process than to continue. During development, +// the reason that it's better to terminate might simply be that the error +// handling code isn't in place yet; in production, the reason might be that +// the author of the code truly believes that x will always be true, but that +// they recognizes that if they are wrong, abrupt and unpleasant process +// termination is still better than carrying on with the assumption violated. +// +// RTC_CHECK always evaluates its argument, so it's OK for x to have side +// effects. +// +// - RTC_DCHECK(x) is the same as RTC_CHECK(x)---an assertion that x is always +// true---except that x will only be evaluated in debug builds; in production +// builds, x is simply assumed to be true. This is useful if evaluating x is +// expensive and the expected cost of failing to detect the violated +// assumption is acceptable. You should not handle cases where a production +// build fails to spot a violated condition, even those that would result in +// crashes. If the code needs to cope with the error, make it cope, but don't +// call RTC_DCHECK; if the condition really can't occur, but you'd sleep +// better at night knowing that the process will suicide instead of carrying +// on in case you were wrong, use RTC_CHECK instead of RTC_DCHECK. +// +// RTC_DCHECK only evaluates its argument in debug builds, so if x has visible +// side effects, you need to write e.g. +// bool w = x; RTC_DCHECK(w); +// +// - RTC_CHECK_EQ, _NE, _GT, ..., and RTC_DCHECK_EQ, _NE, _GT, ... are +// specialized variants of RTC_CHECK and RTC_DCHECK that print prettier +// messages if the condition doesn't hold. Prefer them to raw RTC_CHECK and +// RTC_DCHECK. +// +// - FATAL() aborts unconditionally. + +namespace rtc { +namespace webrtc_checks_impl { +enum class CheckArgType : int8_t { + kEnd = 0, + kInt, + kLong, + kLongLong, + kUInt, + kULong, + kULongLong, + kDouble, + kLongDouble, + kCharP, + kStdString, + kStringView, + kVoidP, + + // kCheckOp doesn't represent an argument type. Instead, it is sent as the + // first argument from RTC_CHECK_OP to make FatalLog use the next two + // arguments to build the special CHECK_OP error message + // (the "a == b (1 vs. 2)" bit). + kCheckOp, +}; + +#if RTC_CHECK_MSG_ENABLED +RTC_NORETURN RTC_EXPORT void FatalLog(const char* file, + int line, + const char* message, + const CheckArgType* fmt, + ...); +#else +RTC_NORETURN RTC_EXPORT void FatalLog(const char* file, int line); +#endif + +// Wrapper for log arguments. Only ever make values of this type with the +// MakeVal() functions. +template <CheckArgType N, typename T> +struct Val { + static constexpr CheckArgType Type() { return N; } + T GetVal() const { return val; } + T val; +}; + +// Case for when we need to construct a temp string and then print that. +// (We can't use Val<CheckArgType::kStdString, const std::string*> +// because we need somewhere to store the temp string.) +struct ToStringVal { + static constexpr CheckArgType Type() { return CheckArgType::kStdString; } + const std::string* GetVal() const { return &val; } + std::string val; +}; + +inline Val<CheckArgType::kInt, int> MakeVal(int x) { + return {x}; +} +inline Val<CheckArgType::kLong, long> MakeVal(long x) { + return {x}; +} +inline Val<CheckArgType::kLongLong, long long> MakeVal(long long x) { + return {x}; +} +inline Val<CheckArgType::kUInt, unsigned int> MakeVal(unsigned int x) { + return {x}; +} +inline Val<CheckArgType::kULong, unsigned long> MakeVal(unsigned long x) { + return {x}; +} +inline Val<CheckArgType::kULongLong, unsigned long long> MakeVal( + unsigned long long x) { + return {x}; +} + +inline Val<CheckArgType::kDouble, double> MakeVal(double x) { + return {x}; +} +inline Val<CheckArgType::kLongDouble, long double> MakeVal(long double x) { + return {x}; +} + +inline Val<CheckArgType::kCharP, const char*> MakeVal(const char* x) { + return {x}; +} +inline Val<CheckArgType::kStdString, const std::string*> MakeVal( + const std::string& x) { + return {&x}; +} +inline Val<CheckArgType::kStringView, const absl::string_view*> MakeVal( + const absl::string_view& x) { + return {&x}; +} + +inline Val<CheckArgType::kVoidP, const void*> MakeVal(const void* x) { + return {x}; +} + +// The enum class types are not implicitly convertible to arithmetic types. +template <typename T, + absl::enable_if_t<std::is_enum<T>::value && + !std::is_arithmetic<T>::value>* = nullptr> +inline decltype(MakeVal(std::declval<absl::underlying_type_t<T>>())) MakeVal( + T x) { + return {static_cast<absl::underlying_type_t<T>>(x)}; +} + +template <typename T, decltype(ToLogString(std::declval<T>()))* = nullptr> +ToStringVal MakeVal(const T& x) { + return {ToLogString(x)}; +} + +// Ephemeral type that represents the result of the logging << operator. +template <typename... Ts> +class LogStreamer; + +// Base case: Before the first << argument. +template <> +class LogStreamer<> final { + public: + template <typename U, + typename V = decltype(MakeVal(std::declval<U>())), + absl::enable_if_t<std::is_arithmetic<U>::value || + std::is_enum<U>::value>* = nullptr> + RTC_FORCE_INLINE LogStreamer<V> operator<<(U arg) const { + return LogStreamer<V>(MakeVal(arg), this); + } + + template <typename U, + typename V = decltype(MakeVal(std::declval<U>())), + absl::enable_if_t<!std::is_arithmetic<U>::value && + !std::is_enum<U>::value>* = nullptr> + RTC_FORCE_INLINE LogStreamer<V> operator<<(const U& arg) const { + return LogStreamer<V>(MakeVal(arg), this); + } + +#if RTC_CHECK_MSG_ENABLED + template <typename... Us> + RTC_NORETURN RTC_FORCE_INLINE static void Call(const char* file, + const int line, + const char* message, + const Us&... args) { + static constexpr CheckArgType t[] = {Us::Type()..., CheckArgType::kEnd}; + FatalLog(file, line, message, t, args.GetVal()...); + } + + template <typename... Us> + RTC_NORETURN RTC_FORCE_INLINE static void CallCheckOp(const char* file, + const int line, + const char* message, + const Us&... args) { + static constexpr CheckArgType t[] = {CheckArgType::kCheckOp, Us::Type()..., + CheckArgType::kEnd}; + FatalLog(file, line, message, t, args.GetVal()...); + } +#else + template <typename... Us> + RTC_NORETURN RTC_FORCE_INLINE static void Call(const char* file, + const int line) { + FatalLog(file, line); + } +#endif +}; + +// Inductive case: We've already seen at least one << argument. The most recent +// one had type `T`, and the earlier ones had types `Ts`. +template <typename T, typename... Ts> +class LogStreamer<T, Ts...> final { + public: + RTC_FORCE_INLINE LogStreamer(T arg, const LogStreamer<Ts...>* prior) + : arg_(arg), prior_(prior) {} + + template <typename U, + typename V = decltype(MakeVal(std::declval<U>())), + absl::enable_if_t<std::is_arithmetic<U>::value || + std::is_enum<U>::value>* = nullptr> + RTC_FORCE_INLINE LogStreamer<V, T, Ts...> operator<<(U arg) const { + return LogStreamer<V, T, Ts...>(MakeVal(arg), this); + } + + template <typename U, + typename V = decltype(MakeVal(std::declval<U>())), + absl::enable_if_t<!std::is_arithmetic<U>::value && + !std::is_enum<U>::value>* = nullptr> + RTC_FORCE_INLINE LogStreamer<V, T, Ts...> operator<<(const U& arg) const { + return LogStreamer<V, T, Ts...>(MakeVal(arg), this); + } + +#if RTC_CHECK_MSG_ENABLED + template <typename... Us> + RTC_NORETURN RTC_FORCE_INLINE void Call(const char* file, + const int line, + const char* message, + const Us&... args) const { + prior_->Call(file, line, message, arg_, args...); + } + + template <typename... Us> + RTC_NORETURN RTC_FORCE_INLINE void CallCheckOp(const char* file, + const int line, + const char* message, + const Us&... args) const { + prior_->CallCheckOp(file, line, message, arg_, args...); + } +#else + template <typename... Us> + RTC_NORETURN RTC_FORCE_INLINE void Call(const char* file, + const int line) const { + prior_->Call(file, line); + } +#endif + + private: + // The most recent argument. + T arg_; + + // Earlier arguments. + const LogStreamer<Ts...>* prior_; +}; + +template <bool isCheckOp> +class FatalLogCall final { + public: + FatalLogCall(const char* file, int line, const char* message) + : file_(file), line_(line), message_(message) {} + + // This can be any binary operator with precedence lower than <<. + template <typename... Ts> + RTC_NORETURN RTC_FORCE_INLINE void operator&( + const LogStreamer<Ts...>& streamer) { +#if RTC_CHECK_MSG_ENABLED + isCheckOp ? streamer.CallCheckOp(file_, line_, message_) + : streamer.Call(file_, line_, message_); +#else + streamer.Call(file_, line_); +#endif + } + + private: + const char* file_; + int line_; + const char* message_; +}; + +} // namespace webrtc_checks_impl + +// The actual stream used isn't important. We reference |ignored| in the code +// but don't evaluate it; this is to avoid "unused variable" warnings (we do so +// in a particularly convoluted way with an extra ?: because that appears to be +// the simplest construct that keeps Visual Studio from complaining about +// condition being unused). +#define RTC_EAT_STREAM_PARAMETERS(ignored) \ + (true ? true : ((void)(ignored), true)) \ + ? static_cast<void>(0) \ + : ::rtc::webrtc_checks_impl::FatalLogCall<false>("", 0, "") & \ + ::rtc::webrtc_checks_impl::LogStreamer<>() + +// Call RTC_EAT_STREAM_PARAMETERS with an argument that fails to compile if +// values of the same types as |a| and |b| can't be compared with the given +// operation, and that would evaluate |a| and |b| if evaluated. +#define RTC_EAT_STREAM_PARAMETERS_OP(op, a, b) \ + RTC_EAT_STREAM_PARAMETERS(((void)::rtc::Safe##op(a, b))) + +// RTC_CHECK dies with a fatal error if condition is not true. It is *not* +// controlled by NDEBUG or anything else, so the check will be executed +// regardless of compilation mode. +// +// We make sure RTC_CHECK et al. always evaluates |condition|, as +// doing RTC_CHECK(FunctionWithSideEffect()) is a common idiom. +// +// RTC_CHECK_OP is a helper macro for binary operators. +// Don't use this macro directly in your code, use RTC_CHECK_EQ et al below. +#if RTC_CHECK_MSG_ENABLED +#define RTC_CHECK(condition) \ + (condition) ? static_cast<void>(0) \ + : ::rtc::webrtc_checks_impl::FatalLogCall<false>( \ + __FILE__, __LINE__, #condition) & \ + ::rtc::webrtc_checks_impl::LogStreamer<>() + +#define RTC_CHECK_OP(name, op, val1, val2) \ + ::rtc::Safe##name((val1), (val2)) \ + ? static_cast<void>(0) \ + : ::rtc::webrtc_checks_impl::FatalLogCall<true>( \ + __FILE__, __LINE__, #val1 " " #op " " #val2) & \ + ::rtc::webrtc_checks_impl::LogStreamer<>() << (val1) << (val2) +#else +#define RTC_CHECK(condition) \ + (condition) \ + ? static_cast<void>(0) \ + : true ? ::rtc::webrtc_checks_impl::FatalLogCall<false>(__FILE__, \ + __LINE__, "") & \ + ::rtc::webrtc_checks_impl::LogStreamer<>() \ + : ::rtc::webrtc_checks_impl::FatalLogCall<false>("", 0, "") & \ + ::rtc::webrtc_checks_impl::LogStreamer<>() + +#define RTC_CHECK_OP(name, op, val1, val2) \ + ::rtc::Safe##name((val1), (val2)) \ + ? static_cast<void>(0) \ + : true ? ::rtc::webrtc_checks_impl::FatalLogCall<true>(__FILE__, \ + __LINE__, "") & \ + ::rtc::webrtc_checks_impl::LogStreamer<>() \ + : ::rtc::webrtc_checks_impl::FatalLogCall<false>("", 0, "") & \ + ::rtc::webrtc_checks_impl::LogStreamer<>() +#endif + +#define RTC_CHECK_EQ(val1, val2) RTC_CHECK_OP(Eq, ==, val1, val2) +#define RTC_CHECK_NE(val1, val2) RTC_CHECK_OP(Ne, !=, val1, val2) +#define RTC_CHECK_LE(val1, val2) RTC_CHECK_OP(Le, <=, val1, val2) +#define RTC_CHECK_LT(val1, val2) RTC_CHECK_OP(Lt, <, val1, val2) +#define RTC_CHECK_GE(val1, val2) RTC_CHECK_OP(Ge, >=, val1, val2) +#define RTC_CHECK_GT(val1, val2) RTC_CHECK_OP(Gt, >, val1, val2) + +// The RTC_DCHECK macro is equivalent to RTC_CHECK except that it only generates +// code in debug builds. It does reference the condition parameter in all cases, +// though, so callers won't risk getting warnings about unused variables. +#if RTC_DCHECK_IS_ON +#define RTC_DCHECK(condition) RTC_CHECK(condition) +#define RTC_DCHECK_EQ(v1, v2) RTC_CHECK_EQ(v1, v2) +#define RTC_DCHECK_NE(v1, v2) RTC_CHECK_NE(v1, v2) +#define RTC_DCHECK_LE(v1, v2) RTC_CHECK_LE(v1, v2) +#define RTC_DCHECK_LT(v1, v2) RTC_CHECK_LT(v1, v2) +#define RTC_DCHECK_GE(v1, v2) RTC_CHECK_GE(v1, v2) +#define RTC_DCHECK_GT(v1, v2) RTC_CHECK_GT(v1, v2) +#else +#define RTC_DCHECK(condition) RTC_EAT_STREAM_PARAMETERS(condition) +#define RTC_DCHECK_EQ(v1, v2) RTC_EAT_STREAM_PARAMETERS_OP(Eq, v1, v2) +#define RTC_DCHECK_NE(v1, v2) RTC_EAT_STREAM_PARAMETERS_OP(Ne, v1, v2) +#define RTC_DCHECK_LE(v1, v2) RTC_EAT_STREAM_PARAMETERS_OP(Le, v1, v2) +#define RTC_DCHECK_LT(v1, v2) RTC_EAT_STREAM_PARAMETERS_OP(Lt, v1, v2) +#define RTC_DCHECK_GE(v1, v2) RTC_EAT_STREAM_PARAMETERS_OP(Ge, v1, v2) +#define RTC_DCHECK_GT(v1, v2) RTC_EAT_STREAM_PARAMETERS_OP(Gt, v1, v2) +#endif + +#define RTC_UNREACHABLE_CODE_HIT false +#define RTC_NOTREACHED() RTC_DCHECK(RTC_UNREACHABLE_CODE_HIT) + +// TODO(bugs.webrtc.org/8454): Add an RTC_ prefix or rename differently. +#define FATAL() \ + ::rtc::webrtc_checks_impl::FatalLogCall<false>(__FILE__, __LINE__, \ + "FATAL()") & \ + ::rtc::webrtc_checks_impl::LogStreamer<>() + +// Performs the integer division a/b and returns the result. CHECKs that the +// remainder is zero. +template <typename T> +inline T CheckedDivExact(T a, T b) { + RTC_CHECK_EQ(a % b, 0) << a << " is not evenly divisible by " << b; + return a / b; +} + +} // namespace rtc + +#else // __cplusplus not defined +// C version. Lacks many features compared to the C++ version, but usage +// guidelines are the same. + +#define RTC_CHECK(condition) \ + do { \ + if (!(condition)) { \ + rtc_FatalMessage(__FILE__, __LINE__, \ + RTC_CHECK_EVAL_MESSAGE("CHECK failed: " #condition)); \ + } \ + } while (0) + +#define RTC_CHECK_EQ(a, b) RTC_CHECK((a) == (b)) +#define RTC_CHECK_NE(a, b) RTC_CHECK((a) != (b)) +#define RTC_CHECK_LE(a, b) RTC_CHECK((a) <= (b)) +#define RTC_CHECK_LT(a, b) RTC_CHECK((a) < (b)) +#define RTC_CHECK_GE(a, b) RTC_CHECK((a) >= (b)) +#define RTC_CHECK_GT(a, b) RTC_CHECK((a) > (b)) + +#define RTC_DCHECK(condition) \ + do { \ + if (RTC_DCHECK_IS_ON && !(condition)) { \ + rtc_FatalMessage(__FILE__, __LINE__, \ + RTC_CHECK_EVAL_MESSAGE("DCHECK failed: " #condition)); \ + } \ + } while (0) + +#define RTC_DCHECK_EQ(a, b) RTC_DCHECK((a) == (b)) +#define RTC_DCHECK_NE(a, b) RTC_DCHECK((a) != (b)) +#define RTC_DCHECK_LE(a, b) RTC_DCHECK((a) <= (b)) +#define RTC_DCHECK_LT(a, b) RTC_DCHECK((a) < (b)) +#define RTC_DCHECK_GE(a, b) RTC_DCHECK((a) >= (b)) +#define RTC_DCHECK_GT(a, b) RTC_DCHECK((a) > (b)) + +#endif // __cplusplus + +#endif // RTC_BASE_CHECKS_H_ |