add: [log] implement simple log function (TBD)

include/libimp/countof.h

@@ -18,10 +18,10 @@ LIBIMP_NAMESPACE_BEG_
  * @see https://en.cppreference.com/w/cpp/iterator/size
 */
 
-namespace detail {
+namespace detail_countof {
 
 template <typename T>
-struct countof_trait_has_size {
+struct trait_has_size {
 private:
   template <typename Type>
   static std::true_type check(decltype(std::declval<Type>().size())*);
@@ -33,7 +33,7 @@ public:
 };
 
 template <typename T>
-struct countof_trait_has_Size {
+struct trait_has_Size {
 private:
   template <typename Type>
   static std::true_type check(decltype(std::declval<Type>().Size())*);
@@ -44,34 +44,34 @@ public:
   constexpr static auto value = type::value;
 };
 
-template <typename C, bool = countof_trait_has_size<C>::value
-                    , bool = countof_trait_has_Size<C>::value>
-struct countof_trait;
+template <typename C, bool = trait_has_size<C>::value
+                    , bool = trait_has_Size<C>::value>
+struct trait;
 
 template <typename T, std::size_t N>
-struct countof_trait<T[N], false, false> {
+struct trait<T[N], false, false> {
   constexpr static auto countof(T const (&)[N]) noexcept {
     return N;
   }
 };
 
 template <typename C, bool B>
-struct countof_trait<C, true, B> {
+struct trait<C, true, B> {
   constexpr static auto countof(C const &c) noexcept(noexcept(c.size())) {
     return c.size();
   }
 };
 
 template <typename C>
-struct countof_trait<C, false, true> {
+struct trait<C, false, true> {
   constexpr static auto countof(C const &c) noexcept(noexcept(c.Size())) {
     return c.Size();
   }
 };
 
-} // namespace detail
+} // namespace detail_countof
 
-template <typename C, typename R = detail::countof_trait<C>>
+template <typename C, typename R = detail_countof::trait<C>>
 constexpr auto countof(C const &c) noexcept(noexcept(R::countof(c))) {
   return R::countof(c);
 }

include/libimp/log.h

@@ -0,0 +1,144 @@
+/**
+ * @file libimp/log.h
+ * @author mutouyun (orz@orzz.org)
+ * @brief Simple log output component
+ * @date 2022-05-22
+ */
+#pragma once
+
+#include <string>
+#include <type_traits>
+
+#include "fmt/format.h"
+
+#include "libimp/def.h"
+#include "libimp/detect_plat.h"
+#include "libimp/export.h"
+
+LIBIMP_NAMESPACE_BEG_
+
+namespace detail_log {
+
+template <typename T>
+class has_fn_info {
+  static std::false_type check(...);
+  template <typename U>
+  static auto check(U *u) -> decltype(u->info(std::declval<std::string>()), std::true_type{});
+
+public:
+  using type = decltype(check(static_cast<T *>(nullptr)));
+};
+
+template <typename T>
+constexpr bool has_fn_info_v = typename has_fn_info<T>::type::value;
+
+template <typename T>
+class has_fn_error {
+  static std::false_type check(...);
+  template <typename U>
+  static auto check(U *u) -> decltype(u->error(std::declval<std::string>()), std::true_type{});
+
+public:
+  using type = decltype(check(static_cast<T *>(nullptr)));
+};
+
+template <typename T>
+constexpr bool has_fn_error_v = typename has_fn_error<T>::type::value;
+
+struct vtable_t {
+  void (*info )(void *, std::string &&);
+  void (*error)(void *, std::string &&);
+};
+
+template <typename T>
+class traits {
+  template <typename U>
+  static auto make_fn_info() noexcept
+    -> std::enable_if_t<has_fn_info_v<U>, void (*)(void *, std::string &&)> {
+    return [](void *p, std::string &&s) {
+      static_cast<U *>(p)->info(std::move(s));
+    };
+  }
+  template <typename U>
+  static auto make_fn_info() noexcept
+    -> std::enable_if_t<!has_fn_info_v<U>, void (*)(void *, std::string &&)> {
+    return [](void *, std::string &&) {};
+  }
+
+  template <typename U>
+  static auto make_fn_error() noexcept
+    -> std::enable_if_t<has_fn_error_v<U>, void (*)(void *, std::string &&)> {
+    return [](void *p, std::string &&s) {
+      static_cast<U *>(p)->error(std::move(s));
+    };
+  }
+  template <typename U>
+  static auto make_fn_error() noexcept
+    -> std::enable_if_t<!has_fn_error_v<U>, void (*)(void *, std::string &&)> {
+    return [](void *, std::string &&) {};
+  }
+
+public:
+  static auto make_vtable() noexcept {
+    static vtable_t vt {
+      make_fn_info <T>(),
+      make_fn_error<T>(),
+    };
+    return &vt;
+  }
+};
+
+class prefix {
+  std::string px_;
+
+public:
+  template <typename... A>
+  prefix(A &&... args) {
+    LIBIMP_UNUSED auto unfold = {
+      0, ((px_ += ::fmt::format("[{}]", std::forward<A>(args))), 0)...
+    };
+  }
+
+  operator std::string() const noexcept {
+    return px_;
+  }
+};
+
+} // namespace detail_log
+
+class LIBIMP_EXPORT log_printer {
+  void *objp_ {nullptr};
+  detail_log::vtable_t *vtable_ {nullptr};
+
+public:
+  log_printer() noexcept = default;
+
+  template <typename T>
+  log_printer(T &p) noexcept
+    : objp_  (static_cast<void *>(&p))
+    , vtable_(detail_log::traits<T>::make_vtable()) {}
+
+  explicit operator bool() const noexcept;
+
+  void info (std::string &&);
+  void error(std::string &&);
+};
+
+class LIBIMP_EXPORT log_std_t {
+public:
+  void info (std::string &&) const;
+  void error(std::string &&) const;
+};
+
+LIBIMP_EXPORT extern log_std_t log_std;
+
+namespace log {
+
+template <typename Fmt, typename... A>
+std::string fmt(Fmt &&ft, A &&... args) {
+  return ::fmt::format(std::forward<Fmt>(ft), std::forward<A>(args)...);
+}
+
+} // namespace log
+
+LIBIMP_NAMESPACE_END_

include/libimp/result.h

@@ -8,6 +8,7 @@
 
 #include <type_traits>
 #include <cstdint>
+#include <span>
 
 #include "fmt/format.h"
 

src/libimp/log.cpp

@@ -0,0 +1,33 @@
+
+#include <utility>
+#include <iostream>
+
+#include "libimp/log.h"
+
+LIBIMP_NAMESPACE_BEG_
+
+log_printer::operator bool() const noexcept {
+  return (objp_ != nullptr) && (vtable_ != nullptr);
+}
+
+void log_printer::info(std::string && s) {
+  if (!*this) return;
+  vtable_->info(objp_, std::move(s));
+}
+
+void log_printer::error(std::string && s) {
+  if (!*this) return;
+  vtable_->error(objp_, std::move(s));
+}
+
+log_std_t log_std;
+
+void log_std_t::info(std::string && s) const {
+  std::cout << std::move(s);
+}
+
+void log_std_t::error(std::string && s) const {
+  std::cerr << std::move(s);
+}
+
+LIBIMP_NAMESPACE_END_

src/libipc/mmap.cpp

@@ -0,0 +1,7 @@
+#include "libipc/mmap.h"
+
+LIBIPC_NAMESPACE_BEG_
+
+
+
+LIBIPC_NAMESPACE_END_

src/libipc/platform/posix/mmap.h

@@ -0,0 +1,27 @@
+/**
+ * @file libimp/platform/posix/mmap.h
+ * @author mutouyun (orz@orzz.org)
+ */
+#pragma once
+
+#include <string>
+#include <cstddef>
+
+#include "libipc/mmap.h"
+
+LIBIPC_NAMESPACE_BEG_
+
+struct mmap_handle {
+  std::string file;
+  std::size_t f_sz;
+  std::size_t f_of;
+  void *memp;
+};
+
+inline int mmap_open_(mmap_t *h_out, std::string const &file, int fd, int flags, std::size_t f_sz, std::size_t f_of) noexcept {
+  if (h_out == nullptr) {
+    return -1;
+  }
+}
+
+LIBIPC_NAMESPACE_END_

test/test_imp_log.cpp

@@ -0,0 +1,90 @@
+
+#include "gtest/gtest.h"
+
+#include "libimp/log.h"
+
+TEST(log, detail) {
+  EXPECT_FALSE(imp::detail_log::has_fn_info_v<int>);
+  EXPECT_FALSE(imp::detail_log::has_fn_error_v<int>);
+
+  struct foo {
+    int info(std::string);
+  };
+  EXPECT_TRUE (imp::detail_log::has_fn_info_v<foo>);
+  EXPECT_FALSE(imp::detail_log::has_fn_error_v<foo>);
+
+  struct bar {
+    int info(char const *);
+    void error(std::string &&);
+  };
+  EXPECT_FALSE(imp::detail_log::has_fn_info_v<bar>);
+  EXPECT_TRUE (imp::detail_log::has_fn_error_v<bar>);
+
+  struct str {
+    str(std::string const &);
+  };
+  struct foo_bar {
+    void info(std::string const &);
+    void error(str);
+  };
+  EXPECT_TRUE(imp::detail_log::has_fn_info_v<foo_bar>);
+  EXPECT_TRUE(imp::detail_log::has_fn_error_v<foo_bar>);
+
+  auto vt_int = imp::detail_log::traits<int>::make_vtable();
+  EXPECT_NE(vt_int, nullptr);
+  vt_int->info (nullptr, "123");
+  vt_int->error(nullptr, "321");
+
+  struct log {
+    std::string what;
+    void error(std::string &&s) {
+      what += s;
+    }
+  } ll;
+  auto vt_log = imp::detail_log::traits<log>::make_vtable();
+  EXPECT_NE(vt_log, nullptr);
+  vt_log->info (&ll, "123");
+  vt_log->error(&ll, "321");
+  vt_log->info (&ll, "654");
+  vt_log->error(&ll, "456");
+  EXPECT_EQ(ll.what, "321456");
+}
+
+TEST(log, log_printer) {
+  struct log {
+    std::string i;
+    std::string e;
+    void info(std::string &&s) {
+      i += s;
+    }
+    void error(std::string &&s) {
+      e += s;
+    }
+  } ll;
+
+  imp::log_printer pt = ll;
+  pt.info("hello ");
+  pt.error("failed: ");
+  pt.info("log-pt");
+  pt.error("whatever");
+  EXPECT_EQ(ll.i, "hello log-pt");
+  EXPECT_EQ(ll.e, "failed: whatever");
+
+  imp::log_printer ps = imp::log_std;
+  ps.info("hello world\n");
+}
+
+#include <chrono>
+#include <fmt/chrono.h>
+
+TEST(log, prefix) {
+  imp::detail_log::prefix prefix;
+  EXPECT_EQ(std::string{prefix}, "");
+
+  prefix = {"hello", "world"};
+  EXPECT_EQ(std::string{prefix}, "[hello][world]");
+
+  using namespace std::literals::chrono_literals;
+  prefix = {"time", imp::log::fmt("{:%H:%M:%S}", 3h + 15min + 30s)};
+  EXPECT_EQ(std::string{prefix}, "[time][03:15:30]");
+}

test/test_imp_utility.cpp

@@ -94,8 +94,8 @@ TEST(utility, countof) {
   struct {
     constexpr int Size() const noexcept { return 3; }
   } sv;
-  EXPECT_FALSE(imp::detail::countof_trait_has_size<decltype(sv)>::value);
-  EXPECT_TRUE (imp::detail::countof_trait_has_Size<decltype(sv)>::value);
+  EXPECT_FALSE(imp::detail_countof::trait_has_size<decltype(sv)>::value);
+  EXPECT_TRUE (imp::detail_countof::trait_has_Size<decltype(sv)>::value);
 
   std::vector<int> vec {1, 2, 3, 4, 5};
   int arr[] {7, 6, 5, 4, 3, 2, 1};