Add system

include/libipc/imp/system.h

@@ -0,0 +1,33 @@
+/**
+ * \file libipc/system.h
+ * \author mutouyun (orz@orzz.org)
+ * \brief Isolation and encapsulation of system APIs.
+ */
+#pragma once
+
+#include <string>
+#include <ostream>  // std::ostream
+#include <cstdint>
+
+#include "libipc/imp/export.h"
+#include "libipc/imp/error.h"
+#include "libipc/imp/result.h"
+
+namespace ipc {
+namespace sys {
+
+/// \brief A platform-dependent error code.
+LIBIPC_EXPORT std::error_code error() noexcept;
+
+/// \enum The name of the `conf()` argument used to inquire about its value.
+/// \brief Certain options are supported, 
+/// or what the value is of certain configurable constants or limits.
+enum class info : std::int32_t {
+  page_size,
+};
+
+/// \brief Get system configuration information at run time.
+LIBIPC_EXPORT result<std::int64_t> conf(info) noexcept;
+
+} // namespace sys
+} // namespace ipc

src/libipc/imp/system.cpp

@@ -0,0 +1,7 @@
+
+#include "libipc/imp/detect_plat.h"
+#if defined(LIBIPC_OS_WIN)
+# include "libipc/platform/win/system.h"
+#else
+# include "libipc/platform/posix/system.h"
+#endif

src/libipc/platform/posix/system.h

@@ -0,0 +1,49 @@
+/**
+ * \file libipc/platform/posix/system.h
+ * \author mutouyun (orz@orzz.org)
+ */
+#pragma once
+
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "libipc/imp/system.h"
+#include "libipc/imp/log.h"
+
+namespace ipc {
+namespace sys {
+
+/**
+ * \brief Get the system error number.
+ * \see https://en.cppreference.com/w/cpp/error/generic_category
+ *      https://man7.org/linux/man-pages/man3/errno.3.html
+*/
+std::error_code error() noexcept {
+  return std::error_code(errno, std::generic_category());
+}
+
+/**
+ * \brief Gets configuration information at run time
+ * https://man7.org/linux/man-pages/man2/getpagesize.2.html
+ * https://man7.org/linux/man-pages/man3/sysconf.3.html
+ */
+result<std::int64_t> conf(info r) noexcept {
+  LIBIPC_LOG();
+  switch (r) {
+  case info::page_size: {
+    auto val = ::sysconf(_SC_PAGESIZE);
+    if (val >= 0) return static_cast<std::int64_t>(val);
+    break;
+  }
+  default:
+    log.error("invalid info = ", underlyof(r));
+    return std::make_error_code(std::errc::invalid_argument);
+  }
+  auto err = sys::error();
+  log.error("info = ", underlyof(r), ", error = ", err);
+  return err;
+}
+
+} // namespace sys
+} // namespace ipc

src/libipc/platform/win/system.h

@@ -0,0 +1,88 @@
+/**
+ * \file libipc/platform/win/system.h
+ * \author mutouyun (orz@orzz.org)
+ */
+#pragma once
+
+#include <exception>
+#include <type_traits>
+
+#include <Windows.h>
+#include <tchar.h>
+
+#include "libipc/imp/system.h"
+#include "libipc/imp/log.h"
+#include "libipc/imp/codecvt.h"
+#include "libipc/imp/generic.h"
+#include "libipc/imp/detect_plat.h"
+#include "libipc/imp/scope_exit.h"
+
+namespace ipc {
+namespace sys {
+
+/**
+ * \brief Gets a text description of the system error
+ * \see https://docs.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-formatmessage
+ */
+std::string error_string(DWORD code) noexcept {
+  LIBIPC_LOG();
+  LIBIPC_TRY {
+    LPTSTR lpErrText = NULL;
+    if (::FormatMessage(
+          FORMAT_MESSAGE_ALLOCATE_BUFFER | 
+          FORMAT_MESSAGE_FROM_SYSTEM | 
+          FORMAT_MESSAGE_IGNORE_INSERTS,
+          NULL,
+          code,
+          MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+          (LPTSTR)&lpErrText,
+          0, NULL) == 0) {
+      log.error("failed: FormatMessage(dwMessageId = ", code, "). error = ", ::GetLastError());
+      return {};
+    }
+    LIBIPC_SCOPE_EXIT(finally) = [lpErrText] { ::LocalFree(lpErrText); };
+    std::size_t msg_len = ::_tcslen(lpErrText);
+    std::size_t len = cvt_cstr(lpErrText, msg_len, (char *)nullptr, 0);
+    if (len == 0) {
+      return {};
+    }
+    std::string ret(len, '\0');
+    cvt_cstr(lpErrText, msg_len, &ret[0], ret.size());
+    return ret;
+  } LIBIPC_CATCH(...) {
+    log.error("failed: FormatMessage(dwMessageId = ", code, ").",
+              "\n\texception: ", log::exception_string(std::current_exception()));
+  }
+  return {};
+}
+
+/**
+ * \brief Get the system error number.
+ * \see https://en.cppreference.com/w/cpp/error/system_category
+ *      https://docs.microsoft.com/en-us/windows/win32/api/errhandlingapi/nf-errhandlingapi-getlasterror
+*/
+std::error_code error() noexcept {
+  return std::error_code(::GetLastError(), std::system_category());
+}
+
+/**
+ * \brief Retrieves information about the current system.
+ * \see https://docs.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-getsysteminfo
+ *      https://docs.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-getnativesysteminfo
+ */
+result<std::int64_t> conf(info r) noexcept {
+  LIBIPC_LOG();
+  switch (r) {
+  case info::page_size: {
+    ::SYSTEM_INFO info {};
+    ::GetNativeSystemInfo(&info);
+    return (std::int64_t)info.dwPageSize;
+  }
+  default:
+    log.error("invalid info = ", underlyof(r));
+    return std::make_error_code(std::errc::invalid_argument);
+  }
+}
+
+} // namespace sys
+} // namespace ipc

test/imp/test_imp_system.cpp

@@ -0,0 +1,10 @@
+
+#include "test.h"
+
+#include "libipc/imp/system.h"
+
+TEST(system, conf) {
+  auto ret = ipc::sys::conf(ipc::sys::info::page_size);
+  EXPECT_TRUE(ret);
+  EXPECT_EQ(ret.value(), 4096);
+}