#include <folly/Format.h>
#include <folly/experimental/logging/LogCategory.h>
#include <folly/experimental/logging/LogLevel.h>
+#include <folly/experimental/logging/LogStream.h>
+#include <folly/experimental/logging/LogStreamProcessor.h>
+
+/**
+ * Helper macro for implementing FB_LOG() and FB_LOGF().
+ *
+ * This macro generally should not be used directly by end users.
+ */
+#define FB_LOG_IMPL(logger, level, type, ...) \
+ (!(logger).getCategory()->logCheck(level)) \
+ ? (void)0 \
+ : ::folly::LogStreamProcessor{(logger).getCategory(), \
+ (level), \
+ __FILE__, \
+ __LINE__, \
+ (type), \
+ ##__VA_ARGS__} & \
+ ::folly::LogStream()
/**
* Log a message to the specified logger.
*
* This macro avoids evaluating the log arguments unless the log level check
* succeeds.
+ *
+ * Beware that the logger argument is evaluated twice, so this argument should
+ * be an expression with no side-effects.
*/
-#define FB_LOG(logger, level, msg, ...) \
- do { \
- const auto fbLogLevelTmp = ::folly::LogLevel::level; \
- const auto& fbLoggerTmp = (logger); \
- if (fbLoggerTmp.logCheck(fbLogLevelTmp)) { \
- fbLoggerTmp.log( \
- fbLogLevelTmp, __FILE__, __LINE__, (msg), ##__VA_ARGS__); \
- } \
- } while (0)
+#define FB_LOG(logger, level, ...) \
+ FB_LOG_IMPL( \
+ logger, \
+ ::folly::LogLevel::level, \
+ ::folly::LogStreamProcessor::APPEND, \
+ ##__VA_ARGS__)
/**
* Log a message to the specified logger, using a folly::format() string.
*
* This macro avoids evaluating the log arguments unless the log level check
* succeeds.
+ *
+ * Beware that the logger argument is evaluated twice, so this argument should
+ * be an expression with no side-effects.
*/
-#define FB_LOGF(logger, level, fmt, ...) \
- do { \
- const auto fbLogLevelTmp = ::folly::LogLevel::level; \
- const auto& fbLoggerTmp = (logger); \
- if (fbLoggerTmp.logCheck(fbLogLevelTmp)) { \
- fbLoggerTmp.logf( \
- fbLogLevelTmp, __FILE__, __LINE__, (fmt), ##__VA_ARGS__); \
- } \
- } while (0)
+#define FB_LOGF(logger, level, fmt, arg1, ...) \
+ FB_LOG_IMPL( \
+ logger, \
+ ::folly::LogLevel::level, \
+ ::folly::LogStreamProcessor::FORMAT, \
+ fmt, \
+ arg1, \
+ ##__VA_ARGS__)
namespace folly {
*/
Logger(LoggerDB* db, folly::StringPiece name);
- /**
- * Get the effective level for this logger.
- *
- * This is the minimum log level of this logger, or any of its parents.
- * Log messages below this level will be ignored, while messages at or
- * above this level need to be processed by this logger or one of its
- * parents.
- */
- LogLevel getEffectiveLevel() const {
- return category_->getEffectiveLevel();
- }
-
- /**
- * Check whether this Logger or any of its parent Loggers would do anything
- * with a log message at the given level.
- */
- bool logCheck(LogLevel level) const {
- // We load the effective level using std::memory_order_relaxed.
- //
- // We want to make log checks as lightweight as possible. It's fine if we
- // don't immediately respond to changes made to the log level from other
- // threads. We can wait until some other operation triggers a memory
- // barrier before we honor the new log level setting. No other memory
- // accesses depend on the log level value. Callers should not rely on all
- // other threads to immediately stop logging as soon as they decrease the
- // log level for a given category.
- return category_->getEffectiveLevelRelaxed() <= level;
- }
-
- /**
- * Unconditionally log a message.
- *
- * The caller is responsible for calling logCheck() before log() to ensure
- * that this log message should be admitted. This is typically done with one
- * of the logging macros.
- */
- void log(
- LogLevel level,
- folly::StringPiece filename,
- unsigned int lineNumber,
- std::string&& msg) const;
- void log(
- LogLevel level,
- folly::StringPiece filename,
- unsigned int lineNumber,
- folly::StringPiece msg) const;
-
- /**
- * Unconditionally log a message.
- *
- * This concatenates the arguments into a string using
- * folly::to<std::string>()
- */
- template <typename... Args>
- void log(
- LogLevel level,
- folly::StringPiece filename,
- unsigned int lineNumber,
- Args&&... args) const {
- std::string msg;
- try {
- msg = folly::to<std::string>(std::forward<Args>(args)...);
- } catch (const std::exception& ex) {
- // This most likely means there was some error converting the arguments
- // to strings. Handle the exception here, rather than letting it
- // propagate up, since callers generally do not expect log statements to
- // throw.
- //
- // Just log an error message letting indicating that something went wrong
- // formatting the log message.
- msg =
- folly::to<std::string>("error constructing log message: ", ex.what());
- }
- log(level, filename, lineNumber, std::move(msg));
- }
-
- /**
- * Unconditionally log a message using a format string.
- *
- * This uses folly::format() to format the message.
- */
- template <typename... Args>
- void logf(
- LogLevel level,
- folly::StringPiece filename,
- unsigned int lineNumber,
- folly::StringPiece fmt,
- Args&&... args) const {
- std::string msg;
- try {
- msg = folly::sformat(fmt, std::forward<Args>(args)...);
- } catch (const std::exception& ex) {
- // This most likely means that the caller had a bug in their format
- // string/arguments. Handle the exception here, rather than letting it
- // propagate up, since callers generally do not expect log statements to
- // throw.
- //
- // Log the format string by itself, to help the developer at least
- // identify the buggy format string in their code.
- msg = folly::to<std::string>(
- "error formatting log message: ",
- ex.what(),
- "; format string: ",
- fmt);
- }
- log(level, filename, lineNumber, std::move(msg));
- }
-
/**
* Get the LogCategory that this Logger refers to.
*/
projects / folly.git / blobdiff