Merge pull request #1307 from eudoxos/ringbuffer-sink

Add ringbuffer sink

include/spdlog/details/circular_q.h

@@ -72,6 +72,27 @@ public:
         return v_[head_];
     }
 
+    // Return number of elements actually stored
+    size_t size() const
+    {
+        if (tail_ >= head_)
+        {
+           return tail_ - head_;
+        }
+        else
+        {
+            return max_items_ - (head_ - tail_ );
+        }
+    }
+
+    // Return const reference to item by index.
+    // If index is out of range 0…size()-1, the behavior is undefined.
+    const T &at(size_t i) const
+    {
+        assert(i < size());
+        return v_[(head_+ i) % max_items_];
+    }
+
     // Pop item from front.
     // If there are no elements in the container, the behavior is undefined.
     void pop_front()

include/spdlog/sinks/ringbuffer_sink-inl.h

@@ -0,0 +1,46 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+#include "spdlog/sinks/ringbuffer_sink.h"
+#endif
+
+#include "spdlog/common.h"
+#include "spdlog/details/os.h"
+
+namespace spdlog {
+namespace sinks {
+
+template<typename Mutex>
+SPDLOG_INLINE ringbuffer_sink<Mutex>::ringbuffer_sink(size_t buf_size)
+{
+    buf_=details::circular_q<details::log_msg_buffer>(buf_size);
+}
+
+template<typename Mutex>
+SPDLOG_INLINE void ringbuffer_sink<Mutex>::sink_it_(const details::log_msg &msg)
+{
+    buf_.push_back(details::log_msg_buffer{msg});
+}
+
+template<typename Mutex>
+SPDLOG_INLINE std::vector<std::string> ringbuffer_sink<Mutex>::last(size_t lim)
+{
+    std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
+    std::vector<std::string> ret;
+    ret.reserve(lim);
+    size_t num=0;
+    for(size_t i=0; i<buf_.size(); i++){
+        num++;
+        memory_buf_t formatted;
+        base_sink<Mutex>::formatter_->format(buf_.at(i), formatted);
+        ret.push_back(fmt::to_string(formatted));
+        if(lim>0 && num==lim) break;
+    }
+    return ret;
+}
+
+} // namespace sinks
+} // namespace spdlog

include/spdlog/sinks/ringbuffer_sink.h

@@ -0,0 +1,60 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include "spdlog/details/null_mutex.h"
+#include "spdlog/sinks/base_sink.h"
+#include "spdlog/details/synchronous_factory.h"
+#include "spdlog/details/circular_q.h"
+#include "spdlog/details/log_msg_buffer.h"
+
+#include <mutex>
+#include <string>
+#include <vector>
+
+namespace spdlog {
+namespace sinks {
+/*
+ * Ring buffer sink
+ */
+template<typename Mutex>
+class ringbuffer_sink final : public base_sink<Mutex>
+{
+public:
+    explicit ringbuffer_sink(size_t buf_size);
+    std::vector<std::string> last(size_t lim=0);
+
+protected:
+    void sink_it_(const details::log_msg &msg) override;
+    void flush_() override {};
+
+private:
+    details::circular_q<details::log_msg_buffer> buf_;
+};
+
+using ringbuffer_sink_mt = ringbuffer_sink<std::mutex>;
+using ringbuffer_sink_st = ringbuffer_sink<details::null_mutex>;
+
+} // namespace sinks
+
+//
+// factory functions
+//
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> basic_logger_mt(const std::string &logger_name, size_t buf_size)
+{
+    return Factory::template create<sinks::ringbuffer_sink_mt>(logger_name, buf_size);
+}
+
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> basic_logger_st(const std::string &logger_name, size_t buf_size)
+{
+    return Factory::template create<sinks::ringbuffer_sink_st>(logger_name, buf_size);
+}
+
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "ringbuffer_sink-inl.h"
+#endif