constexpr support for source location without leading directory

include/spdlog/common.h

@@ -16,20 +16,13 @@
 #include <type_traits>
 
 #include "details/null_mutex.h"
+#include "source_loc.h"
 #include "tweakme.h"
 
 #if __has_include(<version>)
     #include <version>
 #endif
 
-#if __cpp_lib_source_location >= 201907
-    #include <source_location>
-    #define SPDLOG_HAVE_STD_SOURCE_LOCATION
-#elif __has_include(<experimental/source_location>)
-    #include <experimental/source_location>
-    #define SPDLOG_HAVE_EXPERIMENTAL_SOURCE_LOCATION
-#endif
-
 #ifdef SPDLOG_USE_STD_FORMAT
     #if __cpp_lib_format >= 202207L
         #include <format>
@@ -94,7 +87,7 @@ class sink;
 
 #if defined(_WIN32) && defined(SPDLOG_WCHAR_FILENAMES)
 using filename_t = std::wstring;
-    // allow macro expansion to occur in SPDLOG_FILENAME_T
+// allow macro expansion to occur in SPDLOG_FILENAME_T
     #define SPDLOG_FILENAME_T_INNER(s) L##s
     #define SPDLOG_FILENAME_T(s) SPDLOG_FILENAME_T_INNER(s)
 #else
@@ -180,6 +173,7 @@ using atomic_level_t = std::atomic<level>;
 [[nodiscard]] constexpr size_t level_to_number(level lvl) noexcept {
     return static_cast<size_t>(lvl);
 }
+
 constexpr auto levels_count = level_to_number(level::n_levels);
 constexpr std::array<string_view_t, levels_count> level_string_views SPDLOG_LEVEL_NAMES;
 constexpr std::array<string_view_t, levels_count> short_level_names SPDLOG_SHORT_LEVEL_NAMES;
@@ -214,7 +208,9 @@ enum class pattern_time_type {
 class SPDLOG_API spdlog_ex : public std::exception {
 public:
     explicit spdlog_ex(std::string msg);
+
     spdlog_ex(const std::string &msg, int last_errno);
+
     [[nodiscard]] const char *what() const noexcept override;
 
 private:
@@ -222,54 +218,27 @@ private:
 };
 
 [[noreturn]] SPDLOG_API void throw_spdlog_ex(const std::string &msg, int last_errno);
+
 [[noreturn]] SPDLOG_API void throw_spdlog_ex(std::string msg);
 
-struct source_loc {
-    constexpr source_loc() = default;
-    constexpr source_loc(const char *filename_in,
-                         std::uint_least32_t line_in,
-                         const char *funcname_in)
-        : filename{filename_in},
-          line{line_in},
-          funcname{funcname_in} {}
-
-#ifdef SPDLOG_HAVE_STD_SOURCE_LOCATION
-    static constexpr source_loc current(
-        const std::source_location source_location = std::source_location::current()) {
-        return source_loc{source_location.file_name(), source_location.line(),
-                          source_location.function_name()};
-    }
-#elif defined(SPDLOG_HAVE_EXPERIMENTAL_SOURCE_LOCATION)
-    static constexpr source_loc current(const std::experimental::source_location source_location =
-                                            std::experimental::source_location::current()) {
-        return source_loc{source_location.file_name(), source_location.line(),
-                          source_location.function_name()};
-    }
-#else  // no source location support
-    static constexpr source_loc current() { return source_loc{}; }
-#endif
-
-    [[nodiscard]] constexpr bool empty() const noexcept { return line == 0; }
-    const char *filename{nullptr};
-    std::uint_least32_t line{0};
-    const char *funcname{nullptr};
-};
-
 // trick to capture format string and caller's source location with variadic template.
 // see logger::info() etc. to understand how it's used.
 struct loc_with_fmt {
     source_loc loc;
     string_view_t fmt_string;
+
     template <typename S, typename = is_convertible_to_sv<S>>
     constexpr loc_with_fmt(S fmt_str, source_loc loc = source_loc::current()) noexcept
         : loc(loc),
           fmt_string(fmt_str) {}
 
 #ifndef SPDLOG_USE_STD_FORMAT
+
     constexpr loc_with_fmt(fmt::runtime_format_string<char> fmt_str,
                            source_loc loc = source_loc::current()) noexcept
         : loc(loc),
           fmt_string(fmt_str.str) {}
+
 #endif
 };
 
@@ -324,11 +293,13 @@ template <typename T, typename... Args>
 }
     #endif
 #else  // {fmt} version
+
 template <typename T, typename... Args>
 [[nodiscard]] constexpr fmt::basic_string_view<T> to_string_view(
     fmt::basic_format_string<T, Args...> fmt) noexcept {
     return fmt;
 }
+
 #endif
 
 }  // namespace details

include/spdlog/source_loc.h

@@ -0,0 +1,74 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+#include <cstdint>
+
+#if __has_include(<version>)
+    #include <version>
+#endif
+
+#if __cpp_lib_source_location >= 201907
+    #include <source_location>
+    #define SPDLOG_HAVE_STD_SOURCE_LOCATION
+#elif __has_include(<experimental/source_location>)
+    #include <experimental/source_location>
+    #define SPDLOG_HAVE_EXPERIMENTAL_SOURCE_LOCATION
+#endif
+
+namespace spdlog {
+// source location - either initiated from std::source_location or from
+// std::experimental::source_location or empty
+struct source_loc {
+    constexpr source_loc() = default;
+    constexpr source_loc(const char *filename_in,
+                         std::uint_least32_t line_in,
+                         const char *funcname_in)
+        : filename{filename_in},
+          short_filename{basename(filename_in)},
+          line{line_in},
+          funcname{funcname_in} {}
+
+#ifdef SPDLOG_HAVE_STD_SOURCE_LOCATION
+    static constexpr source_loc current(
+        const std::source_location source_location = std::source_location::current()) {
+        return source_loc{source_location.file_name(), source_location.line(),
+                          source_location.function_name()};
+    }
+#elif defined(SPDLOG_HAVE_EXPERIMENTAL_SOURCE_LOCATION)
+    static constexpr source_loc current(const std::experimental::source_location source_location =
+                                            std::experimental::source_location::current()) {
+        return source_loc{source_location.file_name(), source_location.line(),
+                          source_location.function_name()};
+    }
+#else  // no source location support
+    static constexpr source_loc current() { return source_loc{}; }
+#endif
+
+    [[nodiscard]] constexpr bool empty() const noexcept {
+        return line == 0 || filename == nullptr || short_filename == nullptr;
+    }
+
+    const char *filename{nullptr};
+    const char *short_filename{nullptr};
+    std::uint_least32_t line{0};
+    const char *funcname{nullptr};
+
+    // return filename without the leading path
+    static constexpr const char *basename(const char *path) {
+        const char *file = path;
+        while (*path) {
+#ifdef _WIN32
+            if (*path == '\\' || *path == '/')
+#else
+            if (*path == '/')
+#endif
+            {
+                file = path + 1;
+            }
+            ++path;
+        }
+        return file;
+    }
+};
+}  // namespace spdlog

src/pattern_formatter.cpp

@@ -679,35 +679,12 @@ public:
     explicit short_filename_formatter(padding_info padinfo)
         : flag_formatter(padinfo) {}
 
-#ifdef _MSC_VER
-    #pragma warning(push)
-    #pragma warning(disable : 4127)  // consider using 'if constexpr' instead
-#endif                               // _MSC_VER
-    static const char *basename(const char *filename) {
-        // if the size is 2 (1 character + null terminator) we can use the more efficient strrchr
-        // the branch will be elided by optimizations
-        if (sizeof(os::folder_seps) == 2) {
-            const char *rv = std::strrchr(filename, os::folder_seps[0]);
-            return rv != nullptr ? rv + 1 : filename;
-        } else {
-            const std::reverse_iterator<const char *> begin(filename + std::strlen(filename));
-            const std::reverse_iterator<const char *> end(filename);
-
-            const auto it = std::find_first_of(begin, end, std::begin(os::folder_seps),
-                                               std::end(os::folder_seps) - 1);
-            return it != end ? it.base() : filename;
-        }
-    }
-#ifdef _MSC_VER
-    #pragma warning(pop)
-#endif  // _MSC_VER
-
     void format(const details::log_msg &msg, const std::tm &, memory_buf_t &dest) override {
         if (msg.source.empty()) {
             ScopedPadder p(0, padinfo_, dest);
             return;
         }
-        auto filename = basename(msg.source.filename);
+        const char *filename = msg.source.short_filename;
         size_t text_size = padinfo_.enabled() ? std::char_traits<char>::length(filename) : 0;
         ScopedPadder p(text_size, padinfo_, dest);
         fmt_helper::append_string_view(filename, dest);
@@ -841,9 +818,7 @@ public:
         // add source location if present
         if (!msg.source.empty()) {
             dest.push_back('[');
-            const char *filename =
-                details::short_filename_formatter<details::null_scoped_padder>::basename(
-                    msg.source.filename);
+            const char *filename = msg.source.short_filename;
             fmt_helper::append_string_view(filename, dest);
             dest.push_back(':');
             fmt_helper::append_int(msg.source.line, dest);