/*
* Copyright (C) 2015 The Android Open Source Project
*
* 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
*
* http://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.
*/
#ifndef ANDROID_BASE_LOGGING_H
#define ANDROID_BASE_LOGGING_H
// NOTE: For Windows, you must include logging.h after windows.h to allow the
// following code to suppress the evil ERROR macro:
#ifdef _WIN32
// windows.h includes wingdi.h which defines an evil macro ERROR.
#ifdef ERROR
#undef ERROR
#endif
#endif
#include <functional>
#include <memory>
#include <ostream>
#include "android-base/macros.h"
namespace android {
namespace base {
enum LogSeverity {
VERBOSE,
DEBUG,
INFO,
WARNING,
ERROR,
FATAL,
};
enum LogId {
DEFAULT,
MAIN,
SYSTEM,
};
typedef std::function<void(LogId, LogSeverity, const char*, const char*,
unsigned int, const char*)> LogFunction;
extern void StderrLogger(LogId, LogSeverity, const char*, const char*,
unsigned int, const char*);
#ifdef __ANDROID__
// We expose this even though it is the default because a user that wants to
// override the default log buffer will have to construct this themselves.
class LogdLogger {
public:
explicit LogdLogger(LogId default_log_id = android::base::MAIN);
void operator()(LogId, LogSeverity, const char* tag, const char* file,
unsigned int line, const char* message);
private:
LogId default_log_id_;
};
#endif
// Configure logging based on ANDROID_LOG_TAGS environment variable.
// We need to parse a string that looks like
//
// *:v jdwp:d dalvikvm:d dalvikvm-gc:i dalvikvmi:i
//
// The tag (or '*' for the global level) comes first, followed by a colon and a
// letter indicating the minimum priority level we're expected to log. This can
// be used to reveal or conceal logs with specific tags.
extern void InitLogging(char* argv[], LogFunction&& logger);
// Configures logging using the default logger (logd for the device, stderr for
// the host).
extern void InitLogging(char* argv[]);
// Replace the current logger.
extern void SetLogger(LogFunction&& logger);
// Get the minimum severity level for logging.
extern LogSeverity GetMinimumLogSeverity();
class ErrnoRestorer {
public:
ErrnoRestorer()
: saved_errno_(errno) {
}
~ErrnoRestorer() {
errno = saved_errno_;
}
// Allow this object to be used as part of && operation.
operator bool() const {
return true;
}
private:
const int saved_errno_;
DISALLOW_COPY_AND_ASSIGN(ErrnoRestorer);
};
// Logs a message to logcat on Android otherwise to stderr. If the severity is
// FATAL it also causes an abort. For example:
//
// LOG(FATAL) << "We didn't expect to reach here";
#define LOG(severity) LOG_TO(DEFAULT, severity)
// Logs a message to logcat with the specified log ID on Android otherwise to
// stderr. If the severity is FATAL it also causes an abort.
// Use an if-else statement instead of just an if statement here. So if there is a
// else statement after LOG() macro, it won't bind to the if statement in the macro.
// do-while(0) statement doesn't work here. Because we need to support << operator
// following the macro, like "LOG(DEBUG) << xxx;".
#define LOG_TO(dest, severity) \
UNLIKELY(::android::base::severity >= ::android::base::GetMinimumLogSeverity()) && \
::android::base::ErrnoRestorer() && \
::android::base::LogMessage(__FILE__, __LINE__, \
::android::base::dest, \
::android::base::severity, -1).stream()
// A variant of LOG that also logs the current errno value. To be used when
// library calls fail.
#define PLOG(severity) PLOG_TO(DEFAULT, severity)
// Behaves like PLOG, but logs to the specified log ID.
#define PLOG_TO(dest, severity) \
UNLIKELY(::android::base::severity >= ::android::base::GetMinimumLogSeverity()) && \
::android::base::ErrnoRestorer() && \
::android::base::LogMessage(__FILE__, __LINE__, \
::android::base::dest, \
::android::base::severity, errno).stream()
// Marker that code is yet to be implemented.
#define UNIMPLEMENTED(level) \
LOG(level) << __PRETTY_FUNCTION__ << " unimplemented "
// Check whether condition x holds and LOG(FATAL) if not. The value of the
// expression x is only evaluated once. Extra logging can be appended using <<
// after. For example:
//
// CHECK(false == true) results in a log message of
// "Check failed: false == true".
#define CHECK(x) \
LIKELY((x)) || \
::android::base::LogMessage(__FILE__, __LINE__, ::android::base::DEFAULT, \
::android::base::FATAL, -1).stream() \
<< "Check failed: " #x << " "
// Helper for CHECK_xx(x,y) macros.
#define CHECK_OP(LHS, RHS, OP) \
for (auto _values = ::android::base::MakeEagerEvaluator(LHS, RHS); \
UNLIKELY(!(_values.lhs OP _values.rhs)); \
/* empty */) \
::android::base::LogMessage(__FILE__, __LINE__, ::android::base::DEFAULT, \
::android::base::FATAL, -1).stream() \
<< "Check failed: " << #LHS << " " << #OP << " " << #RHS \
<< " (" #LHS "=" << _values.lhs << ", " #RHS "=" << _values.rhs << ") "
// Check whether a condition holds between x and y, LOG(FATAL) if not. The value
// of the expressions x and y is evaluated once. Extra logging can be appended
// using << after. For example:
//
// CHECK_NE(0 == 1, false) results in
// "Check failed: false != false (0==1=false, false=false) ".
#define CHECK_EQ(x, y) CHECK_OP(x, y, == )
#define CHECK_NE(x, y) CHECK_OP(x, y, != )
#define CHECK_LE(x, y) CHECK_OP(x, y, <= )
#define CHECK_LT(x, y) CHECK_OP(x, y, < )
#define CHECK_GE(x, y) CHECK_OP(x, y, >= )
#define CHECK_GT(x, y) CHECK_OP(x, y, > )
// Helper for CHECK_STRxx(s1,s2) macros.
#define CHECK_STROP(s1, s2, sense) \
if (LIKELY((strcmp(s1, s2) == 0) == sense)) \
; \
else \
LOG(FATAL) << "Check failed: " \
<< "\"" << s1 << "\"" \
<< (sense ? " == " : " != ") << "\"" << s2 << "\""
// Check for string (const char*) equality between s1 and s2, LOG(FATAL) if not.
#define CHECK_STREQ(s1, s2) CHECK_STROP(s1, s2, true)
#define CHECK_STRNE(s1, s2) CHECK_STROP(s1, s2, false)
// Perform the pthread function call(args), LOG(FATAL) on error.
#define CHECK_PTHREAD_CALL(call, args, what) \
do { \
int rc = call args; \
if (rc != 0) { \
errno = rc; \
PLOG(FATAL) << #call << " failed for " << what; \
} \
} while (false)
// CHECK that can be used in a constexpr function. For example:
//
// constexpr int half(int n) {
// return
// DCHECK_CONSTEXPR(n >= 0, , 0)
// CHECK_CONSTEXPR((n & 1) == 0),
// << "Extra debugging output: n = " << n, 0)
// n / 2;
// }
#define CHECK_CONSTEXPR(x, out, dummy) \
(UNLIKELY(!(x))) \
? (LOG(FATAL) << "Check failed: " << #x out, dummy) \
:
// DCHECKs are debug variants of CHECKs only enabled in debug builds. Generally
// CHECK should be used unless profiling identifies a CHECK as being in
// performance critical code.
#if defined(NDEBUG)
static constexpr bool kEnableDChecks = false;
#else
static constexpr bool kEnableDChecks = true;
#endif
#define DCHECK(x) \
if (::android::base::kEnableDChecks) CHECK(x)
#define DCHECK_EQ(x, y) \
if (::android::base::kEnableDChecks) CHECK_EQ(x, y)
#define DCHECK_NE(x, y) \
if (::android::base::kEnableDChecks) CHECK_NE(x, y)
#define DCHECK_LE(x, y) \
if (::android::base::kEnableDChecks) CHECK_LE(x, y)
#define DCHECK_LT(x, y) \
if (::android::base::kEnableDChecks) CHECK_LT(x, y)
#define DCHECK_GE(x, y) \
if (::android::base::kEnableDChecks) CHECK_GE(x, y)
#define DCHECK_GT(x, y) \
if (::android::base::kEnableDChecks) CHECK_GT(x, y)
#define DCHECK_STREQ(s1, s2) \
if (::android::base::kEnableDChecks) CHECK_STREQ(s1, s2)
#define DCHECK_STRNE(s1, s2) \
if (::android::base::kEnableDChecks) CHECK_STRNE(s1, s2)
#if defined(NDEBUG)
#define DCHECK_CONSTEXPR(x, out, dummy)
#else
#define DCHECK_CONSTEXPR(x, out, dummy) CHECK_CONSTEXPR(x, out, dummy)
#endif
// Temporary class created to evaluate the LHS and RHS, used with
// MakeEagerEvaluator to infer the types of LHS and RHS.
template <typename LHS, typename RHS>
struct EagerEvaluator {
EagerEvaluator(LHS l, RHS r) : lhs(l), rhs(r) {
}
LHS lhs;
RHS rhs;
};
// Helper function for CHECK_xx.
template <typename LHS, typename RHS>
static inline EagerEvaluator<LHS, RHS> MakeEagerEvaluator(LHS lhs, RHS rhs) {
return EagerEvaluator<LHS, RHS>(lhs, rhs);
}
// Explicitly instantiate EagerEvalue for pointers so that char*s aren't treated
// as strings. To compare strings use CHECK_STREQ and CHECK_STRNE. We rely on
// signed/unsigned warnings to protect you against combinations not explicitly
// listed below.
#define EAGER_PTR_EVALUATOR(T1, T2) \
template <> \
struct EagerEvaluator<T1, T2> { \
EagerEvaluator(T1 l, T2 r) \
: lhs(reinterpret_cast<const void*>(l)), \
rhs(reinterpret_cast<const void*>(r)) { \
} \
const void* lhs; \
const void* rhs; \
}
EAGER_PTR_EVALUATOR(const char*, const char*);
EAGER_PTR_EVALUATOR(const char*, char*);
EAGER_PTR_EVALUATOR(char*, const char*);
EAGER_PTR_EVALUATOR(char*, char*);
EAGER_PTR_EVALUATOR(const unsigned char*, const unsigned char*);
EAGER_PTR_EVALUATOR(const unsigned char*, unsigned char*);
EAGER_PTR_EVALUATOR(unsigned char*, const unsigned char*);
EAGER_PTR_EVALUATOR(unsigned char*, unsigned char*);
EAGER_PTR_EVALUATOR(const signed char*, const signed char*);
EAGER_PTR_EVALUATOR(const signed char*, signed char*);
EAGER_PTR_EVALUATOR(signed char*, const signed char*);
EAGER_PTR_EVALUATOR(signed char*, signed char*);
// Data for the log message, not stored in LogMessage to avoid increasing the
// stack size.
class LogMessageData;
// A LogMessage is a temporarily scoped object used by LOG and the unlikely part
// of a CHECK. The destructor will abort if the severity is FATAL.
class LogMessage {
public:
LogMessage(const char* file, unsigned int line, LogId id,
LogSeverity severity, int error);
~LogMessage();
// Returns the stream associated with the message, the LogMessage performs
// output when it goes out of scope.
std::ostream& stream();
// The routine that performs the actual logging.
static void LogLine(const char* file, unsigned int line, LogId id,
LogSeverity severity, const char* msg);
private:
const std::unique_ptr<LogMessageData> data_;
DISALLOW_COPY_AND_ASSIGN(LogMessage);
};
// Allows to temporarily change the minimum severity level for logging.
class ScopedLogSeverity {
public:
explicit ScopedLogSeverity(LogSeverity level);
~ScopedLogSeverity();
private:
LogSeverity old_;
};
} // namespace base
} // namespace android
#endif // ANDROID_BASE_LOGGING_H