add: [system] add features

include/libimp/system.h

@@ -0,0 +1,30 @@
+/**
+ * @file libimp/system.h
+ * @author mutouyun (orz@orzz.org)
+ * @brief Isolation and encapsulation of system APIs
+ * @date 2022-08-07
+ */
+#pragma once
+
+#include <string>
+
+#include "libimp/def.h"
+#include "libimp/export.h"
+#include "libimp/result.h"
+
+LIBIMP_NAMESPACE_BEG_
+namespace sys {
+
+/**
+ * @brief Get/Set the system error code
+ */
+LIBIMP_EXPORT result_code error_code() noexcept;
+LIBIMP_EXPORT void error_code(result_code) noexcept;
+
+/**
+ * @brief Gets a text description of the system error
+ */
+LIBIMP_EXPORT std::string error_msg(result_code) noexcept;
+
+} // namespace sys
+LIBIMP_NAMESPACE_END_

src/libimp/platform/posix/system.h

@@ -0,0 +1,47 @@
+/**
+ * @file libimp/platform/posix/system.h
+ * @author mutouyun (orz@orzz.org)
+ */
+#pragma once
+
+#include <exception>
+#include <memory>
+#include <type_traits>
+
+#include <errno.h>
+#include <string.h>
+
+#include "libimp/system.h"
+#include "libimp/log.h"
+
+LIBIMP_NAMESPACE_BEG_
+namespace sys {
+
+/**
+ * @brief Get the system error code
+ * https://man7.org/linux/man-pages/man3/errno.3.html
+ */
+result_code error_code() noexcept {
+  auto err = errno;
+  if (err == 0) return {true};
+  return {false, std::uint64_t(err)};
+}
+
+/**
+ * @brief Set the system error code
+ * https://man7.org/linux/man-pages/man3/errno.3.html
+ */
+void error_code(result_code code) noexcept {
+  errno = code ? 0 : (int)code.value();
+}
+
+/**
+ * @brief Gets a text description of the system error
+ * https://man7.org/linux/man-pages/man3/strerror_l.3.html
+ */
+std::string error_msg(result_code code) noexcept {
+  return {};
+}
+
+} // namespace sys
+LIBIMP_NAMESPACE_END_

src/libimp/platform/win/system.h

@@ -0,0 +1,80 @@
+/**
+ * @file libimp/platform/win/system.h
+ * @author mutouyun (orz@orzz.org)
+ */
+#pragma once
+
+#include <exception>
+#include <memory>
+#include <type_traits>
+
+#include <Windows.h>
+#include <tchar.h>
+
+#include "libimp/system.h"
+#include "libimp/log.h"
+#include "libimp/codecvt.h"
+
+LIBIMP_NAMESPACE_BEG_
+namespace sys {
+
+/**
+ * @brief Get the system error code
+ * https://docs.microsoft.com/en-us/windows/win32/api/errhandlingapi/nf-errhandlingapi-getlasterror
+ */
+result_code error_code() noexcept {
+  auto err = ::GetLastError();
+  if (err == ERROR_SUCCESS) return {true};
+  return {false, std::uint64_t(err)};
+}
+
+/**
+ * @brief Set the system error code
+ * https://docs.microsoft.com/en-us/windows/win32/api/errhandlingapi/nf-errhandlingapi-setlasterror
+ */
+void error_code(result_code code) noexcept {
+  DWORD err = code ? ERROR_SUCCESS : (DWORD)code.value();
+  ::SetLastError(err);
+}
+
+/**
+ * @brief Gets a text description of the system error
+ * https://docs.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-formatmessage
+ */
+std::string error_msg(result_code code) noexcept {
+  LIBIMP_LOG_();
+  try {
+    DWORD err = code ? ERROR_SUCCESS : (DWORD)code.value();
+    LPTSTR lpErrText = NULL;
+    if (::FormatMessage(
+          FORMAT_MESSAGE_ALLOCATE_BUFFER | 
+          FORMAT_MESSAGE_FROM_SYSTEM | 
+          FORMAT_MESSAGE_IGNORE_INSERTS,
+          NULL,
+          err,
+          MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+          (LPTSTR)&lpErrText,
+          0, NULL) == 0) {
+      log.error("FormatMessage fails. return = {}", ::GetLastError());
+      return {};
+    }
+    LIBIMP_UNUSED auto buf_guard = std::unique_ptr<std::remove_pointer_t<LPVOID>, 
+                                                   void(*)(LPVOID)> {
+      lpErrText, [](LPVOID lp) { ::LocalFree(lp); }
+    };
+    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;
+  } catch (std::exception const &e) {
+    log.failed(e.what());
+  }
+  return {};
+}
+
+} // namespace sys
+LIBIMP_NAMESPACE_END_

src/libimp/system.cpp

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+#include "libimp/detect_plat.h"
+#if defined(LIBIMP_OS_WIN)
+#include "libimp/platform/win/system.h"
+#else
+#include "libimp/platform/posix/system.h"
+#endif

test/test_imp_system.cpp

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+
+#include "gtest/gtest.h"
+
+#include "libimp/system.h"
+#include "libimp/detect_plat.h"
+#include "libimp/codecvt.h"
+
+#if defined(LIBIMP_OS_WIN)
+#include <WinError.h>
+#else
+#endif
+
+TEST(system, error_code) {
+  EXPECT_TRUE(imp::sys::error_code());
+
+  imp::sys::error_code({false, 111});
+  auto err = imp::sys::error_code();
+  EXPECT_FALSE(err);
+  EXPECT_EQ(err.value(), 111);
+
+  imp::sys::error_code({});
+  EXPECT_TRUE(imp::sys::error_code());
+}
+
+TEST(system, error_msg) {
+#if defined(LIBIMP_OS_WIN)
+  {
+    std::u16string u16_txt = u"操作成功完成。\r\n";
+    std::string s_txt;
+    imp::cvt_sstr(u16_txt, s_txt);
+    EXPECT_EQ(imp::sys::error_msg({}), s_txt);
+  }
+  {
+    std::u16string u16_txt = u"句柄无效。\r\n";
+    std::string s_txt;
+    imp::cvt_sstr(u16_txt, s_txt);
+    EXPECT_EQ(imp::sys::error_msg({false, ERROR_INVALID_HANDLE}), s_txt);
+  }
+#else
+#endif
+}