Add TimeConditional for logging

common/aixlog.hpp

@@ -277,17 +277,14 @@ struct Conditional
     {
     }
 
-    void set(bool value)
+    virtual ~Conditional() = default;
-    {
-        is_true_ = value;
-    }
 
-    bool is_true() const
+    virtual bool is_true() const
     {
         return is_true_;
     }
 
-private:
+protected:
     bool is_true_;
 };
 
@@ -601,7 +598,7 @@ public:
     }
 
 protected:
-    Log() noexcept : last_buffer_(nullptr)
+    Log() noexcept : last_buffer_(nullptr), do_log_(true)
     {
         std::clog.rdbuf(this);
         std::clog << Severity() << Tag() << Function() << Conditional() << AixLog::Color::NONE << std::flush;
@@ -617,7 +614,7 @@ protected:
         std::lock_guard<std::recursive_mutex> lock(mutex_);
         if (!get_stream().str().empty())
         {
-            if (conditional_.is_true())
+            if (do_log_)
             {
                 for (const auto& sink : log_sinks_)
                 {
@@ -639,7 +636,7 @@ protected:
         {
             if (c == '\n')
                 sync();
-            else
+            else if (do_log_)
                 get_stream() << static_cast<char>(c);
         }
         else
@@ -667,11 +664,14 @@ private:
         return *last_buffer_;
     }
 
+    /// one buffer per thread to avoid mixed log lines
     std::map<std::thread::id, std::stringstream> buffer_;
+    /// the last thread id
     std::thread::id last_id_;
+    /// the last buffer
     std::stringstream* last_buffer_ = nullptr;
     Metadata metadata_;
-    Conditional conditional_;
+    bool do_log_;
     std::vector<log_sink_ptr> log_sinks_;
     std::recursive_mutex mutex_;
 };
@@ -1131,7 +1131,7 @@ static std::ostream& operator<<(std::ostream& os, const Severity& log_severity)
             log->metadata_.timestamp = nullptr;
             log->metadata_.tag = nullptr;
             log->metadata_.function = nullptr;
-            log->conditional_.set(true);
+            log->do_log_ = true;
         }
     }
     else
@@ -1192,7 +1192,7 @@ static std::ostream& operator<<(std::ostream& os, const Conditional& conditional
     if (log != nullptr)
     {
         std::lock_guard<std::recursive_mutex> lock(log->mutex_);
-        log->conditional_.set(conditional.is_true());
+        log->do_log_ = conditional.is_true();
     }
     return os;
 }

common/utils/logging.hpp

@@ -0,0 +1,79 @@
+/***
+    This file is part of snapcast
+    Copyright (C) 2014-2021  Johannes Pohl
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#ifndef LOGGING_UTILS_HPP
+#define LOGGING_UTILS_HPP
+
+#include "common/aixlog.hpp"
+#include <chrono>
+
+
+namespace utils
+{
+namespace logging
+{
+
+using namespace std::chrono_literals;
+
+/// Log Conditional to limit log frequency
+struct TimeConditional : public AixLog::Conditional
+{
+    /// c'tor
+    /// @param interval duration that must be passed since the last log line
+    TimeConditional(const std::chrono::milliseconds& interval) : interval_(interval)
+    {
+        reset();
+    }
+
+    /// return true for the next check
+    void reset()
+    {
+        last_time_ = std::chrono::steady_clock::now() - interval_ - 1s;
+    }
+
+    /// Change log interval
+    /// @param interval duration that must be passed since the last log line
+    void setInterval(const std::chrono::milliseconds& interval)
+    {
+        interval_ = interval;
+    }
+
+    /// check if the interval is passed
+    /// @return true if interval passed since the last log
+    bool is_true() const override
+    {
+        auto now = std::chrono::steady_clock::now();
+        if (now > last_time_ + interval_)
+        {
+            last_time_ = now;
+            return true;
+        }
+        return false;
+    }
+
+private:
+    /// log interval
+    std::chrono::milliseconds interval_;
+    /// last log time
+    mutable std::chrono::steady_clock::time_point last_time_;
+};
+
+} // namespace logging
+} // namespace utils
+
+#endif