From 450a11f3b88cb96a214781b0c78d27936c92734c Mon Sep 17 00:00:00 2001
From: Alexey Ochapov <alexez@alexez.com>
Date: Sun, 10 Feb 2019 04:13:18 +0300
Subject: [PATCH] add custom thread id type

---
 include/spdlog/details/log_msg.h           |  2 +-
 include/spdlog/details/os.h                | 31 +++++++++++++++-------
 include/spdlog/details/pattern_formatter.h |  8 ++++++
 include/spdlog/tweakme.h                   | 20 +++++++++++++-
 4 files changed, 49 insertions(+), 12 deletions(-)

diff --git a/include/spdlog/details/log_msg.h b/include/spdlog/details/log_msg.h
index 69422ba3..3c7d9a23 100644
--- a/include/spdlog/details/log_msg.h
+++ b/include/spdlog/details/log_msg.h
@@ -41,7 +41,7 @@ struct log_msg
     const std::string *logger_name{nullptr};
     level::level_enum level{level::off};
     log_clock::time_point time;
-    size_t thread_id{0};
+    details::os::thread_t thread_id{};
     size_t msg_id{0};
 
     // wrapping the formatted text with color (updated by pattern_formatter).
diff --git a/include/spdlog/details/os.h b/include/spdlog/details/os.h
index 646805e6..8ad1f674 100644
--- a/include/spdlog/details/os.h
+++ b/include/spdlog/details/os.h
@@ -310,38 +310,49 @@ inline int utc_minutes_offset(const std::tm &tm = details::os::localtime())
 #endif
 }
 
-// Return current thread id as size_t
+#if defined(SPDLOG_CUSTOM_THREAD_T)
+using thread_t = SPDLOG_CUSTOM_THREAD_T;
+#else
+using thread_t = size_t;
+#endif
+
+// Return current thread id as thread_t
 // It exists because the std::this_thread::get_id() is much slower(especially
 // under VS 2013)
-inline size_t _thread_id() SPDLOG_NOEXCEPT
+inline thread_t _thread_id() SPDLOG_NOEXCEPT
 {
+#if defined(SPDLOG_CUSTOM_THREAD_ID_GETTER)
+    return SPDLOG_CUSTOM_THREAD_ID_GETTER;
+#else
 #ifdef _WIN32
-    return static_cast<size_t>(::GetCurrentThreadId());
+    return static_cast<thread_t>(::GetCurrentThreadId());
 #elif __linux__
+
 #if defined(__ANDROID__) && defined(__ANDROID_API__) && (__ANDROID_API__ < 21)
 #define SYS_gettid __NR_gettid
 #endif
-    return static_cast<size_t>(syscall(SYS_gettid));
+    return static_cast<thread_t>(syscall(SYS_gettid));
 #elif __FreeBSD__
     long tid;
     thr_self(&tid);
-    return static_cast<size_t>(tid);
+    return static_cast<thread_t>(tid);
 #elif __APPLE__
     uint64_t tid;
     pthread_threadid_np(nullptr, &tid);
-    return static_cast<size_t>(tid);
+    return static_cast<thread_t>(tid);
 #else // Default to standard C++11 (other Unix)
-    return static_cast<size_t>(std::hash<std::thread::id>()(std::this_thread::get_id()));
+    return static_cast<thread_t>(std::hash<std::thread::id>()(std::this_thread::get_id()));
+#endif
 #endif
 }
 
-// Return current thread id as size_t (from thread local storage)
-inline size_t thread_id() SPDLOG_NOEXCEPT
+// Return current thread id as thread_t (from thread local storage)
+inline thread_t thread_id() SPDLOG_NOEXCEPT
 {
 #if defined(SPDLOG_NO_TLS)
     return _thread_id();
 #else // cache thread id in tls
-    static thread_local const size_t tid = _thread_id();
+    static thread_local const thread_t tid = _thread_id();
     return tid;
 #endif
 }
diff --git a/include/spdlog/details/pattern_formatter.h b/include/spdlog/details/pattern_formatter.h
index c0ad86e8..fe8f2804 100644
--- a/include/spdlog/details/pattern_formatter.h
+++ b/include/spdlog/details/pattern_formatter.h
@@ -687,6 +687,13 @@ public:
 
     void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
     {
+#if defined(SPDLOG_CUSTOM_THREAD_ID_PRINTER)
+        SPDLOG_CUSTOM_THREAD_ID_PRINTER
+#else
+        using used_thread_t = decltype(msg.thread_id);
+        static_assert(std::is_convertible<used_thread_t, size_t>::value,
+                      "custom thread_t is not convertible to size_t, use SPDLOG_CUSTOM_THREAD_ID_PRINTER macro");
+
         if (padinfo_.enabled())
         {
             const auto field_size = fmt_helper::count_digits(msg.thread_id);
@@ -697,6 +704,7 @@ public:
         {
             fmt_helper::append_int(msg.thread_id, dest);
         }
+#endif
     }
 };
 
diff --git a/include/spdlog/tweakme.h b/include/spdlog/tweakme.h
index b3b71e4f..f9041555 100644
--- a/include/spdlog/tweakme.h
+++ b/include/spdlog/tweakme.h
@@ -142,4 +142,22 @@
 // Defaults to __FUNCTION__ (should work on all compilers) if not defined.
 //
 // #define SPDLOG_FUNCTION __PRETTY_FUNCTION__
-///////////////////////////////////////////////////////////////////////////////
\ No newline at end of file
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment to use custom thread identifier type.
+//
+// WARNING: Custom thread id getter should be used when thread_t is not
+// convertible to size_t (which is default type) or values should be received
+// from another source, e.g. pthread identifiers under Linux.
+//
+// WARNING: If custom thread_t is not convertible to size_t and custom thread
+// id printer code is not set then compile-time assert will fail. Use 
+// SPDLOG_CUSTOM_THREAD_ID_PRINTER macro to provide corresponding code to print
+// thread id. This code will be placed inside t_formatter (for '%t') in
+// details/pattern_formatter.h.
+//
+// #define SPDLOG_CUSTOM_THREAD_T custom_type
+// #define SPDLOG_CUSTOM_THREAD_ID_GETTER custom_type_get_func()
+// #define SPDLOG_CUSTOM_THREAD_ID_PRINTER {  } // see t_formatter::format
+///////////////////////////////////////////////////////////////////////////////