| /* |
| * 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 WEBRTC_BASE_CHECKS_H_ |
| #define WEBRTC_BASE_CHECKS_H_ |
| |
| #include <sstream> |
| #include <string> |
| |
| #include "webrtc/typedefs.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 |
| // she recognizes that if she is 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. |
| // |
| // TODO(ajm): Ideally, checks.h would be combined with logging.h, but |
| // consolidation with system_wrappers/logging.h should happen first. |
| |
| namespace rtc { |
| |
| // Helper macro which avoids evaluating the arguments to a stream if |
| // the condition doesn't hold. |
| #define RTC_LAZY_STREAM(stream, condition) \ |
| !(condition) ? static_cast<void>(0) : rtc::FatalMessageVoidify() & (stream) |
| |
| // The actual stream used isn't important. We reference condition 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(condition) \ |
| (true ? true : !(condition)) \ |
| ? static_cast<void>(0) \ |
| : rtc::FatalMessageVoidify() & rtc::FatalMessage("", 0).stream() |
| |
| // RTC_CHECK dies with a fatal error if condition is not true. It is *not* |
| // controlled by NDEBUG, so the check will be executed regardless of |
| // compilation mode. |
| // |
| // We make sure RTC_CHECK et al. always evaluates their arguments, as |
| // doing RTC_CHECK(FunctionWithSideEffect()) is a common idiom. |
| #define RTC_CHECK(condition) \ |
| RTC_LAZY_STREAM(rtc::FatalMessage(__FILE__, __LINE__).stream(), \ |
| !(condition)) \ |
| << "Check failed: " #condition << std::endl << "# " |
| |
| // Helper macro for binary operators. |
| // Don't use this macro directly in your code, use RTC_CHECK_EQ et al below. |
| // |
| // TODO(akalin): Rewrite this so that constructs like if (...) |
| // RTC_CHECK_EQ(...) else { ... } work properly. |
| #define RTC_CHECK_OP(name, op, val1, val2) \ |
| if (std::string* _result = \ |
| rtc::Check##name##Impl((val1), (val2), #val1 " " #op " " #val2)) \ |
| rtc::FatalMessage(__FILE__, __LINE__, _result).stream() |
| |
| // Build the error message string. This is separate from the "Impl" |
| // function template because it is not performance critical and so can |
| // be out of line, while the "Impl" code should be inline. Caller |
| // takes ownership of the returned string. |
| template<class t1, class t2> |
| std::string* MakeCheckOpString(const t1& v1, const t2& v2, const char* names) { |
| std::ostringstream ss; |
| ss << names << " (" << v1 << " vs. " << v2 << ")"; |
| std::string* msg = new std::string(ss.str()); |
| return msg; |
| } |
| |
| // MSVC doesn't like complex extern templates and DLLs. |
| #if !defined(COMPILER_MSVC) |
| // Commonly used instantiations of MakeCheckOpString<>. Explicitly instantiated |
| // in logging.cc. |
| extern template std::string* MakeCheckOpString<int, int>( |
| const int&, const int&, const char* names); |
| extern template |
| std::string* MakeCheckOpString<unsigned long, unsigned long>( |
| const unsigned long&, const unsigned long&, const char* names); |
| extern template |
| std::string* MakeCheckOpString<unsigned long, unsigned int>( |
| const unsigned long&, const unsigned int&, const char* names); |
| extern template |
| std::string* MakeCheckOpString<unsigned int, unsigned long>( |
| const unsigned int&, const unsigned long&, const char* names); |
| extern template |
| std::string* MakeCheckOpString<std::string, std::string>( |
| const std::string&, const std::string&, const char* name); |
| #endif |
| |
| // Helper functions for RTC_CHECK_OP macro. |
| // The (int, int) specialization works around the issue that the compiler |
| // will not instantiate the template version of the function on values of |
| // unnamed enum type - see comment below. |
| #define DEFINE_RTC_CHECK_OP_IMPL(name, op) \ |
| template <class t1, class t2> \ |
| inline std::string* Check##name##Impl(const t1& v1, const t2& v2, \ |
| const char* names) { \ |
| if (v1 op v2) \ |
| return NULL; \ |
| else \ |
| return rtc::MakeCheckOpString(v1, v2, names); \ |
| } \ |
| inline std::string* Check##name##Impl(int v1, int v2, const char* names) { \ |
| if (v1 op v2) \ |
| return NULL; \ |
| else \ |
| return rtc::MakeCheckOpString(v1, v2, names); \ |
| } |
| DEFINE_RTC_CHECK_OP_IMPL(EQ, ==) |
| DEFINE_RTC_CHECK_OP_IMPL(NE, !=) |
| DEFINE_RTC_CHECK_OP_IMPL(LE, <=) |
| DEFINE_RTC_CHECK_OP_IMPL(LT, < ) |
| DEFINE_RTC_CHECK_OP_IMPL(GE, >=) |
| DEFINE_RTC_CHECK_OP_IMPL(GT, > ) |
| #undef DEFINE_RTC_CHECK_OP_IMPL |
| |
| #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 (!defined(NDEBUG) || defined(DCHECK_ALWAYS_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((v1) == (v2)) |
| #define RTC_DCHECK_NE(v1, v2) RTC_EAT_STREAM_PARAMETERS((v1) != (v2)) |
| #define RTC_DCHECK_LE(v1, v2) RTC_EAT_STREAM_PARAMETERS((v1) <= (v2)) |
| #define RTC_DCHECK_LT(v1, v2) RTC_EAT_STREAM_PARAMETERS((v1) < (v2)) |
| #define RTC_DCHECK_GE(v1, v2) RTC_EAT_STREAM_PARAMETERS((v1) >= (v2)) |
| #define RTC_DCHECK_GT(v1, v2) RTC_EAT_STREAM_PARAMETERS((v1) > (v2)) |
| #endif |
| |
| // This is identical to LogMessageVoidify but in name. |
| class FatalMessageVoidify { |
| public: |
| FatalMessageVoidify() { } |
| // This has to be an operator with a precedence lower than << but |
| // higher than ?: |
| void operator&(std::ostream&) { } |
| }; |
| |
| #define RTC_UNREACHABLE_CODE_HIT false |
| #define RTC_NOTREACHED() RTC_DCHECK(RTC_UNREACHABLE_CODE_HIT) |
| |
| #define FATAL() rtc::FatalMessage(__FILE__, __LINE__).stream() |
| // TODO(ajm): Consider adding RTC_NOTIMPLEMENTED macro when |
| // base/logging.h and system_wrappers/logging.h are consolidated such that we |
| // can match the Chromium behavior. |
| |
| // Like a stripped-down LogMessage from logging.h, except that it aborts. |
| class FatalMessage { |
| public: |
| FatalMessage(const char* file, int line); |
| // Used for RTC_CHECK_EQ(), etc. Takes ownership of the given string. |
| FatalMessage(const char* file, int line, std::string* result); |
| NO_RETURN ~FatalMessage(); |
| |
| std::ostream& stream() { return stream_; } |
| |
| private: |
| void Init(const char* file, int line); |
| |
| std::ostringstream stream_; |
| }; |
| |
| // 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, static_cast<T>(0)); |
| return a / b; |
| } |
| |
| } // namespace rtc |
| |
| #endif // WEBRTC_BASE_CHECKS_H_ |