backtrace sink and refactoring

include/spdlog/details/log_msg.h

@@ -4,16 +4,18 @@
 #pragma once
 
 #include "spdlog/common.h"
+#include <string>
 
 namespace spdlog {
 namespace details {
 struct log_msg
 {
+    log_msg() = default;
     log_msg(source_loc loc, string_view_t logger_name, level::level_enum lvl, string_view_t msg);
     log_msg(string_view_t logger_name, level::level_enum lvl, string_view_t msg);
     log_msg(const log_msg &other) = default;
 
-    const string_view_t logger_name;
+    string_view_t logger_name;
     level::level_enum level{level::off};
     log_clock::time_point time;
     size_t thread_id{0};
@@ -23,7 +25,7 @@ struct log_msg
     mutable size_t color_range_end{0};
 
     source_loc source;
-    const string_view_t payload;
+    string_view_t payload;
 };
 } // namespace details
 } // namespace spdlog

include/spdlog/details/log_msg_buffer.h

@@ -0,0 +1,62 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include "spdlog/details/log_msg.h"
+#include "spdlog/fmt/bundled/core.h"
+
+namespace spdlog {
+namespace details {
+
+// regular log_msgs only holds string_views to stack data - so the cannot be stored for later use.
+// this one can, since it contains and owns the payload buffer.
+struct log_msg_buffer : log_msg
+{
+    fmt::basic_memory_buffer<char, 40> loggername_buf;
+    fmt::basic_memory_buffer<char, 200> payload_buf;
+    log_msg_buffer() = default;
+
+    log_msg_buffer(const log_msg &orig_msg): log_msg(orig_msg)
+    {
+        update_buffers();
+    }
+
+    log_msg_buffer(const log_msg_buffer& other):log_msg(other)
+    {
+        update_buffers();
+    }
+
+    log_msg_buffer(const log_msg_buffer&& other):log_msg(std::move(other))
+    {
+        update_buffers();
+    }
+
+    log_msg_buffer& operator=(log_msg_buffer &other) SPDLOG_NOEXCEPT
+    {
+        *static_cast<log_msg*>(this) = other;
+        update_buffers();
+        return *this;
+    }
+
+    log_msg_buffer& operator=(log_msg_buffer &&other) SPDLOG_NOEXCEPT
+    {
+        *static_cast<log_msg*>(this) = std::move(other);
+        update_buffers();
+        return *this;
+    }
+
+    void update_buffers() SPDLOG_NOEXCEPT
+    {
+        loggername_buf.clear();
+        loggername_buf.append(logger_name.data(), logger_name.data() + logger_name.size());
+        logger_name = string_view_t{loggername_buf.data(), loggername_buf.size()};
+
+        payload_buf.clear();
+        payload_buf.append(payload.data(),payload.data() + payload.size());
+        payload = string_view_t{payload_buf.data(), payload_buf.size()};
+    }
+};
+
+}
+}

include/spdlog/details/thread_pool-inl.h

@@ -100,8 +100,7 @@ bool SPDLOG_INLINE thread_pool::process_next_msg_()
     {
     case async_msg_type::log:
     {
-        auto msg = incoming_async_msg.to_log_msg();
-        incoming_async_msg.worker_ptr->backend_log_(msg);
+        incoming_async_msg.worker_ptr->backend_log_(incoming_async_msg);
         return true;
     }
     case async_msg_type::flush:

include/spdlog/details/thread_pool.h

@@ -3,10 +3,11 @@
 
 #pragma once
 
-#include "spdlog/details/log_msg.h"
+#include "spdlog/details/log_msg_buffer.h"
 #include "spdlog/details/mpmc_blocking_q.h"
 #include "spdlog/details/os.h"
 
+
 #include <chrono>
 #include <memory>
 #include <thread>
@@ -27,17 +28,12 @@ enum class async_msg_type
     terminate
 };
 
+#include "spdlog/details/log_msg_buffer.h"
 // Async msg to move to/from the queue
 // Movable only. should never be copied
-struct async_msg
+struct async_msg:log_msg_buffer
 {
     async_msg_type msg_type {async_msg_type::log};
-    level::level_enum level {level::info};
-    log_clock::time_point time;
-    size_t thread_id {0};
-    fmt::basic_memory_buffer<char, 176> raw;
-
-    source_loc source;
     async_logger_ptr worker_ptr;
 
     async_msg() = default;
@@ -49,51 +45,35 @@ struct async_msg
 // support for vs2013 move
 #if defined(_MSC_VER) && _MSC_VER <= 1800
     async_msg(async_msg &&other)
-        : msg_type(other.msg_type)
-        , level(other.level)
-        , time(other.time)
-        , thread_id(other.thread_id)
-        , raw(move(other.raw))
-        , msg_id(other.msg_id)
-        , source(other.source)
+        : log_msg_buffer(std::move(other))
+        , msg_type(other.msg_type)
         , worker_ptr(std::move(other.worker_ptr))
     {}
 
     async_msg &operator=(async_msg &&other)
+
     {
+        *static_cast<log_msg_buffer*>(this) = std::move(other);
         msg_type = other.msg_type;
-        level = other.level;
-        time = other.time;
-        thread_id = other.thread_id;
-        raw = std::move(other.raw);
-        msg_id = other.msg_id;
-        source = other.source;
         worker_ptr = std::move(other.worker_ptr);
         return *this;
     }
 #else // (_MSC_VER) && _MSC_VER <= 1800
-    async_msg(async_msg &&) = default;
-    async_msg &operator=(async_msg &&) = default;
+    async_msg(async_msg &&) SPDLOG_NOEXCEPT = default;
+    async_msg &operator=(async_msg &&) SPDLOG_NOEXCEPT = default;
 #endif
 
     // construct from log_msg with given type
     async_msg(async_logger_ptr &&worker, async_msg_type the_type, details::log_msg &m)
-        : msg_type(the_type)
-        , level(m.level)
-        , time(m.time)
-        , thread_id(m.thread_id)
-        , source(m.source)
+        : log_msg_buffer(m)
+        , msg_type(the_type)
         , worker_ptr(std::move(worker))
     {
-        raw.append(m.payload.data(), m.payload.data() + m.payload.size());
     }
 
     async_msg(async_logger_ptr &&worker, async_msg_type the_type)
-        : msg_type(the_type)
-        , level(level::off)
-        , time()
-        , thread_id(0)
-        , source()
+        : log_msg_buffer()
+        , msg_type(the_type)
         , worker_ptr(std::move(worker))
     {}
 
@@ -101,17 +81,6 @@ struct async_msg
         : async_msg(nullptr, the_type)
     {}
 
-    // copy into log_msg
-    log_msg to_log_msg()
-    {
-        log_msg msg(string_view_t(worker_ptr->name()), level, string_view_t(raw.data(), raw.size()));
-        msg.time = time;
-        msg.thread_id = thread_id;
-        msg.source = source;
-        msg.color_range_start = 0;
-        msg.color_range_end = 0;
-        return msg;
-    }
 };
 
 class thread_pool

include/spdlog/sinks/backtrace-sink.h

@@ -0,0 +1,98 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include "dist_sink.h"
+#include "spdlog/details/null_mutex.h"
+#include "spdlog/details/log_msg.h"
+#include "spdlog/details/log_msg_buffer.h"
+#include "spdlog/details/circular_q.h"
+
+#include <mutex>
+#include <string>
+#include <chrono>
+
+// Store log messages in circular buffer
+// If it encounters a message with high enough level, it will send all pervious message to its child sinks
+// Useful for storing debug data in case of error/warning happens
+
+//
+// Example:
+//
+//     #include "spdlog/spdlog.h"
+//     #include "spdlog/sinks/backtrace_sink.h
+//
+//     int main() {
+//         auto backtrace_sink = std::make_shared<backtrace_sink>();
+//         backtrace_sink ->add_sink(std::make_shared<stdout_color_sink_mt>());
+//         spdlog::logger l("logger", backtrace_sink);
+//         logger.set_level(spdlog::level::trace);
+//         l.trace("Hello");
+//         l.debug("Hello");
+//         l.info("Hello");
+//         l.warn("This will trigger the log of all prev messages in the queue");
+//     }
+
+
+namespace spdlog {
+namespace sinks {
+template<typename Mutex>
+class backtrace_sink : public dist_sink<Mutex>
+{
+public:
+    explicit backtrace_sink(level::level_enum trigger_level = spdlog::level::warn, size_t n_messages = 32)
+        : trigger_level_{trigger_level}, traceback_msgs_{n_messages}
+    {}
+
+protected:
+    level::level_enum trigger_level_;
+
+    details::circular_q<details::log_msg_buffer> traceback_msgs_;
+
+    // if current message is high enough, trigger a backtrace log,
+    // otherwise save the message in the queue for future trigger.
+    void sink_it_(const details::log_msg &msg) override
+    {
+        if(msg.level < trigger_level_)
+        {
+            traceback_msgs_.push_back(details::log_msg_buffer(msg));
+        }
+        if(msg.level > level::debug)
+        {
+            dist_sink<Mutex>::sink_it_(msg);
+        }
+        if(msg.level >= trigger_level_)
+        {
+            log_backtrace_(msg.logger_name);
+        }
+    }
+
+    void log_backtrace_(const string_view_t& logger_name)
+    {
+        if(traceback_msgs_.empty())
+        {
+            return;
+        }
+
+        dist_sink<Mutex>::sink_it_(details::log_msg{
+            logger_name,level::info,"********************* [Backtrace Start] *********************"});
+
+        do
+        {
+            details::log_msg_buffer popped;
+            traceback_msgs_.pop_front(popped);
+            dist_sink<Mutex>::sink_it_(popped);
+        }
+        while (!traceback_msgs_.empty());
+
+        dist_sink<Mutex>::sink_it_(details::log_msg{
+            logger_name,level::info,"********************* [Backtrace End] ***********************"});
+    }
+};
+
+using backtrace_sink_mt = backtrace_sink<std::mutex>;
+using backtrace_sink_st = backtrace_sink<details::null_mutex>;
+
+} // namespace sinks
+} // namespace spdlog