upd: [imp] optimized log interface implementation

benchmark/benchmark_log.cpp

@@ -6,14 +6,14 @@
 namespace {
 
 void imp_log_no_output(benchmark::State &state) {
-  imp::log::grip log {__func__, {}};
+  LIBIMP_LOG_([](auto &&) {});
   for (auto _ : state) {
     log.debug("hello log.");
   }
 }
 
-void imp_log_gripper(benchmark::State &state) {
-  imp::log::grip log {__func__, {}};
+void imp_log_info(benchmark::State &state) {
+  LIBIMP_LOG_([](auto &&) {});
   for (auto _ : state) {
     log.info("hello log.");
   }
@@ -22,4 +22,4 @@ void imp_log_gripper(benchmark::State &state) {
 } // namespace
 
 BENCHMARK(imp_log_no_output);
-BENCHMARK(imp_log_gripper);
+BENCHMARK(imp_log_info);

include/libimp/fmt.h

@@ -13,6 +13,7 @@
 #include <utility>
 #include <type_traits>
 #include <chrono>   // std::chrono::time_point
+#include <tuple>
 #include <cstddef>
 #include <ctime>    // std::tm, std::localtime
 
@@ -163,5 +164,15 @@ bool tag_invoke(decltype(::LIBIMP::fmt_to), fmt_context &ctx, span<T> s) {
   return true;
 }
 
+template <typename Tp, std::size_t... I>
+bool unfold_tuple_fmt_to(fmt_context &ctx, Tp const &tp, std::index_sequence<I...>) {
+  return fmt_to(ctx, std::get<I>(tp)...);
+}
+
+template <typename... T>
+bool tag_invoke(decltype(::LIBIMP::fmt_to), fmt_context &ctx, std::tuple<T...> const &tp) {
+  return unfold_tuple_fmt_to(ctx, tp, std::index_sequence_for<T...>{});
+}
+
 } // namespace detail
 LIBIMP_NAMESPACE_END_

include/libimp/generic.h

@@ -71,9 +71,9 @@ struct is_same_first<T, T> : std::true_type {};
 } // namespace detail
 
 template <typename T, typename... A>
-using is_not_match = 
+using not_match = 
   typename std::enable_if<!detail::is_same_first<T, 
-  typename std::decay<A>::type...>::value>::type;
+  typename std::decay<A>::type...>::value, bool>::type;
 
 /**
  * \brief Determines whether a type is specialized from a particular template.

include/libimp/log.h

@@ -83,115 +83,55 @@ std::string context_to_string(context<T...> const &l_ctx) noexcept {
   }
 }
 
-namespace detail {
-
-enum out_type : unsigned {
-  out_none    = 0x0,
-  out_string  = 0x1,
-};
-
-template <typename T>
-class has_fn_output {
-  static std::integral_constant<out_type, out_none> check(...);
-
-  template <typename U, typename = decltype(std::declval<U &>().output(log::level::trace, std::declval<std::string>()))>
-  static std::integral_constant<out_type, out_string> check(U *u);
-
-public:
-  using type = decltype(check(static_cast<T *>(nullptr)));
-};
-
-template <typename T>
-constexpr out_type has_fn_output_v = has_fn_output<T>::type::value;
-
-struct vtable_t {
-  void (*output)(void *, log::level, std::string &&);
-};
-
-template <typename T>
-class traits {
-  template <typename U>
-  static auto make_fn_output() noexcept
-    -> std::enable_if_t<(has_fn_output_v<U> == out_none), decltype(vtable_t{}.output)> {
-    return [](void *, log::level, std::string &&) {};
-  }
-
-  template <typename U>
-  static auto make_fn_output() noexcept
-    -> std::enable_if_t<(has_fn_output_v<U> == out_string), decltype(vtable_t{}.output)> {
-    return [](void *p, log::level lev, std::string &&str) {
-      static_cast<U *>(p)->output(lev, std::move(str));
-    };
-  }
-
-public:
-  static auto make_vtable() noexcept {
-    static vtable_t vt { make_fn_output<T>() };
-    return &vt;
-  }
-};
-
-} // namespace detail
-
-class printer {
-  void *objp_ {nullptr};
-  detail::vtable_t *vtable_ {nullptr};
-
-public:
-  printer() noexcept = default;
-
-  template <typename T, 
-            typename = is_not_match<printer, T>>
-  printer(T &p) noexcept
-    : objp_  (static_cast<void *>(&p))
-    , vtable_(detail::traits<T>::make_vtable()) {}
-
-  explicit operator bool() const noexcept {
-    return (objp_ != nullptr) && (vtable_ != nullptr);
-  }
-
-  template <typename... T>
-  void output(context<T...> const &ctx) noexcept {
-    if (!*this) return;
-    LIBIMP_TRY {
-      vtable_->output(objp_, ctx.level, context_to_string(ctx));
-    } LIBIMP_CATCH(...) {}
-  }
-};
-
-/// \class class LIBIMP_EXPORT std_t
-/// \brief Standard console output.
-class LIBIMP_EXPORT std_t {
-public:
-  void output(log::level, std::string &&) noexcept;
-};
-
 /// \brief Standard console output object.
-LIBIMP_EXPORT extern std_t std_out;
+inline auto &make_std_out() noexcept {
+  static auto std_out = [](auto const &ctx) {
+    auto s = context_to_string(ctx);
+    switch (ctx.level) {
+    case level::trace:
+    case level::debug:
+    case level::info:
+      std::fprintf(stdout, "%s\n", s.c_str());
+      break;
+    case level::warning:
+    case level::error:
+    case level::failed:
+      std::fprintf(stderr, "%s\n", s.c_str());
+      break;
+    default:
+      break;
+    }
+  };
+  return std_out;
+}
 
 /**
  * \brief Log information grips.
  */
+template <typename Outputer>
 class grip {
-  printer printer_;
+  Outputer out_;
   char const *func_;
   level level_limit_;
 
   template <typename... A>
   grip &output(log::level l, A &&... args) noexcept {
-    if (!printer_ || (underlyof(l) < underlyof(level_limit_))) {
+    if (underlyof(l) < underlyof(level_limit_)) {
       return *this;
     }
-    printer_.output(context<A &&...> {
+    LIBIMP_TRY {
+      out_(context<A &&...> {
         l, std::chrono::system_clock::now(), func_,
         std::forward_as_tuple(std::forward<A>(args)...),
       });
+    } LIBIMP_CATCH(...) {}
     return *this;
   }
 
 public:
-  grip(char const *func, printer printer = std_out, level level_limit = level::info) noexcept 
-    : printer_    (printer)
+  template <typename O>
+  grip(char const *func, O &&out, level level_limit) noexcept 
+    : out_        (std::forward<O>(out))
     , func_       (func)
     , level_limit_(level_limit) {}
 
@@ -203,7 +143,20 @@ public:
   template <typename... A> grip &failed (A &&...args) noexcept { return output(log::level::failed , std::forward<A>(args)...); }
 };
 
+template <typename O>
+inline auto make_grip(char const *func, O &&out, level level_limit = level::info) noexcept {
+  return grip<std::decay_t<O>>(func, std::forward<O>(out), level_limit);
+}
+
+inline auto make_grip(char const *func, level level_limit = level::info) noexcept {
+  return make_grip(func, make_std_out(), level_limit);
+}
+
+inline auto make_grip(char const */*ignore*/, char const *func, level level_limit = level::info) noexcept {
+  return make_grip(func, make_std_out(), level_limit);
+}
+
 } // namespace log
 LIBIMP_NAMESPACE_END_
 
-#define LIBIMP_LOG_(...) ::LIBIMP::log::grip log(__func__,##__VA_ARGS__)
+#define LIBIMP_LOG_(...) auto log = ::LIBIMP::log::make_grip(__func__,##__VA_ARGS__)

include/libimp/result.h

@@ -139,7 +139,7 @@ private:
 
 public:
   template <typename... A, 
-            typename = is_not_match<result, A...>,
+            typename = not_match<result, A...>,
             typename = decltype(type_traits_t::init_code(std::declval<storage_t &>()
                                                        , std::declval<A>()...))>
   result(A &&... args) noexcept {
@@ -168,7 +168,7 @@ private:
 
 public:
   template <typename... A, 
-            typename = is_not_match<result, A...>,
+            typename = not_match<result, A...>,
             typename = decltype(type_traits_t::init_code(std::declval<storage_t &>()
                                                        , std::declval<A>()...))>
   result(A &&... args) noexcept {

src/libimp/log.cpp

@@ -1,28 +0,0 @@
-#include "libimp/log.h"
-
-#include <cstdio>
-
-LIBIMP_NAMESPACE_BEG_
-namespace log {
-
-std_t std_out;
-
-void std_t::output(log::level l, std::string &&s) noexcept {
-  switch (l) {
-  case level::trace:
-  case level::debug:
-  case level::info:
-    std::fprintf(stdout, "%s\n", s.c_str());
-    break;
-  case level::warning:
-  case level::error:
-  case level::failed:
-    std::fprintf(stderr, "%s\n", s.c_str());
-    break;
-  default:
-    break;
-  }
-}
-
-} // namespace log
-LIBIMP_NAMESPACE_END_

src/libipc/platform/win/get_sa.h

@@ -28,7 +28,7 @@ inline LPSECURITY_ATTRIBUTES get_sa() {
 
     initiator() {
       using namespace ::LIBIMP;
-      log::grip log {"get_sa"};
+      LIBIMP_LOG_("get_sa");
       if (!::InitializeSecurityDescriptor(&sd_, SECURITY_DESCRIPTOR_REVISION)) {
         log.error("failed: InitializeSecurityDescriptor(SECURITY_DESCRIPTOR_REVISION). "
                   "error = ", sys::error());

src/libpmr/memory_resource.cpp

@@ -13,12 +13,11 @@ namespace {
 /**
  * \brief Check that bytes is not 0 and that the alignment is a power of two.
  */
-bool verify_args(::LIBIMP::log::grip &log, std::size_t bytes, std::size_t alignment) noexcept {
+bool verify_args(std::size_t bytes, std::size_t alignment) noexcept {
   if (bytes == 0) {
     return false;
   }
   if ((alignment == 0) || (alignment & (alignment - 1)) != 0) {
-    log.error("invalid bytes = ", bytes, ", alignment = ", alignment);
     return false;
   }
   return true;
@@ -47,7 +46,8 @@ new_delete_resource *new_delete_resource::get() noexcept {
  */
 void *new_delete_resource::allocate(std::size_t bytes, std::size_t alignment) noexcept {
   LIBIMP_LOG_();
-  if (!verify_args(log, bytes, alignment)) {
+  if (!verify_args(bytes, alignment)) {
+    log.error("invalid bytes = ", bytes, ", alignment = ", alignment);
     return nullptr;
   }
 #if defined(LIBIMP_CPP_17)
@@ -89,7 +89,8 @@ void new_delete_resource::deallocate(void *p, std::size_t bytes, std::size_t ali
   if (p == nullptr) {
     return;
   }
-  if (!verify_args(log, bytes, alignment)) {
+  if (!verify_args(bytes, alignment)) {
+    log.error("invalid bytes = ", bytes, ", alignment = ", alignment);
     return;
   }
 #if defined(LIBIMP_CPP_17)

test/imp/test_imp_log.cpp

@@ -6,76 +6,9 @@
 
 #include "libimp/log.h"
 
-TEST(log, detail) {
-  EXPECT_EQ(imp::log::detail::has_fn_output_v<int>, imp::log::detail::out_none);
-
-  struct foo {
-    int info(std::string);
-  };
-  EXPECT_EQ(imp::log::detail::has_fn_output_v<foo>, imp::log::detail::out_none);
-
-  struct bar {
-    int info(char const *);
-    void output(imp::log::level, std::string &&);
-  };
-  EXPECT_EQ(imp::log::detail::has_fn_output_v<bar>, imp::log::detail::out_string);
-
-  struct str {
-    str(std::string const &);
-  };
-  struct foo_bar {
-    void output(imp::log::level, str);
-  };
-  EXPECT_EQ(imp::log::detail::has_fn_output_v<foo_bar>, imp::log::detail::out_string);
-
-  auto vt_int = imp::log::detail::traits<int>::make_vtable();
-  EXPECT_NE(vt_int, nullptr);
-  EXPECT_NO_THROW(vt_int->output(nullptr, imp::log::level::error, ""));
-
-  struct log {
-    std::string what;
-    void output(imp::log::level l, std::string &&s) {
-      if (l == imp::log::level::error) what += s + '\n';
-    }
-  } ll;
-  auto vt_log = imp::log::detail::traits<log>::make_vtable();
-  EXPECT_NE(vt_log, nullptr);
-
-  vt_log->output(&ll, imp::log::level::info, "123");
-  vt_log->output(&ll, imp::log::level::info, "321");
-  vt_log->output(&ll, imp::log::level::info, "654");
-  vt_log->output(&ll, imp::log::level::info, "456");
-  std::cout << ll.what << "\n";
-  SUCCEED();
-}
-
-TEST(log, log_printer) {
-  struct log {
-    std::string i;
-    std::string e;
-
-    void output(imp::log::level l, std::string &&s) {
-      if (l == imp::log::level::error) e += s + "\n";
-      else if (l == imp::log::level::info) i += s + "\n";
-    }
-  } ll;
-
-  imp::log::printer pt = ll;
-  pt.output(imp::log::context<char const *>{imp::log::level::info , std::chrono::system_clock::now(), __func__, "hello "});
-  pt.output(imp::log::context<char const *>{imp::log::level::error, std::chrono::system_clock::now(), __func__, "failed: "});
-  pt.output(imp::log::context<char const *>{imp::log::level::info , std::chrono::system_clock::now(), __func__, "log-pt"});
-  pt.output(imp::log::context<char const *>{imp::log::level::error, std::chrono::system_clock::now(), __func__, "whatever"});
-  std::cout << ll.i << "\n";
-  std::cout << ll.e << "\n";
-
-  imp::log::printer ps = imp::log::std_out;
-  ps.output(imp::log::context<char const *>{imp::log::level::info, std::chrono::system_clock::now(), __func__, "hello world"});
-  SUCCEED();
-}
-
 TEST(log, gripper) {
   {
-    imp::log::grip log {__func__};
+    LIBIMP_LOG_();
     log.info("hello");
   }
   {
@@ -84,3 +17,26 @@ TEST(log, gripper) {
   }
   SUCCEED();
 }
+
+TEST(log, custom) {
+  struct log {
+    std::string i;
+    std::string e;
+  } ll_data;
+  auto ll = [&ll_data](auto &&ctx) mutable {
+    auto s = imp::fmt(ctx.params);
+    if (ctx.level == imp::log::level::error) ll_data.e += s + " ";
+    else
+    if (ctx.level == imp::log::level::info ) ll_data.i += s + " ";
+  };
+
+  LIBIMP_LOG_(ll);
+
+  log.info ("hello");
+  log.error("failed:");
+  log.info ("log-pt");
+  log.error("whatever");
+
+  EXPECT_EQ(ll_data.i, "hello log-pt ");
+  EXPECT_EQ(ll_data.e, "failed: whatever ");
+}