Added attributes

CMakeLists.txt

@@ -146,7 +146,8 @@ set(SPDLOG_HEADERS
         "include/spdlog/sinks/systemd_sink.h"
         "include/spdlog/sinks/tcp_sink.h"
         "include/spdlog/sinks/udp_sink.h"
-        "include/spdlog/sinks/async_sink.h")
+        "include/spdlog/sinks/async_sink.h"
+        "include/spdlog/attributes.h")
 set(SPDLOG_SRCS
         "src/common.cpp"
         "src/logger.cpp"

include/spdlog/attributes.h

@@ -0,0 +1,88 @@
+#pragma once
+
+#include <spdlog/common.h>
+
+#include <mutex>
+#include <unordered_map>
+
+namespace spdlog {
+
+class SPDLOG_API log_attributes {
+public:
+    using attr_map_t = std::unordered_map<std::string, std::string>;
+    using key_t = attr_map_t::key_type;
+    using value_t = attr_map_t::mapped_type;
+    using const_iter = attr_map_t::const_iterator;
+
+    log_attributes() = default;
+    log_attributes(const log_attributes& other) {
+        const auto& o_map = other.get_map();
+        attr_ctx(o_map.begin(), o_map.end());
+    }
+    log_attributes& operator=(const log_attributes& other) {
+        if (this != &other) {
+            clear();
+            const auto& o_map = other.get_map();
+            attr_ctx(o_map.begin(), o_map.end());
+        }
+        return *this;
+    }
+
+    void put(const key_t& key, const value_t& value) {
+        auto lck = lock();
+        attrs[key] = value;
+    }
+
+    void remove(const key_t& key) {
+        auto lck = lock();
+        auto value_it = attrs.find(key);
+        if (value_it != attrs.end()) {
+            attrs.erase(key);
+        }
+    }
+
+    void clear() {
+        auto lck = lock();
+        attrs.clear();
+    }
+
+    bool empty() const {
+        auto lck = lock();
+        return attrs.empty();
+    }
+
+    std::pair<bool, const_iter> const get(key_t const& key) const {
+        auto lck = lock();
+        auto value_it = attrs.find(key);
+
+        return std::make_pair(value_it == attrs.end(), value_it);
+    }
+
+    // provide a local copy of the attributes to be free of race issues
+    // alternative is to lock the attr_map while the formatter iterates over it
+    attr_map_t get_map() const {
+        auto lck = lock();
+        return attrs;
+    }
+
+    template <typename Attribute_Iter>
+    void attr_ctx(Attribute_Iter begin, Attribute_Iter end) {
+        auto lck = lock();
+        attrs.insert(begin, end);
+    }
+
+    void attr_ctx(std::initializer_list<attr_map_t::value_type> attributes) { attr_ctx(attributes.begin(), attributes.end()); }
+
+    bool empty() {
+        auto lck = lock();
+        return attrs.empty();
+    }
+
+private:
+    std::lock_guard<std::mutex> lock() const { return std::lock_guard(attrs_mtx); }
+
+    mutable std::mutex attrs_mtx;
+    attr_map_t attrs;
+};
+
+}  // namespace spdlog