A tool to evaluate methods in creating temp files

tools/win/CreateTempFilesPerfEvaluation/CreateTempFilesPerfEval.cc

+// Copyright (c) 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <windows.h>
+
+#include <shlwapi.h>
+#include <stdio.h>
+#include <tchar.h>
+
+#include <algorithm>
+#include <iostream>
+#include <sstream>
+#include <string>
+
+#pragma warning(disable : 4996)
+
+// Create |count| number of temp files at |kTempDirForGuid| usingGUID based
+// method. The time cost in millisecond of creating every 500 temp files or all
+// the files if |count| < 500 is printed to the console.
+bool CreateFilesUsingGuid(UINT count);
+
+// Create |count| number of temp files at |kTempDirForGetTempFileName| using
+// GetTempFileName() API. The time cost in millisecond of creating every 500
+// temp files or all the files if |count| < 500 is printed to the console.
+bool CreateFilesUsingGetTempFileName(UINT count);
+
+// This method converts GUID to a string.
+char* ConvertGuidToString(const GUID* id, char* out);
+
+// Check if the given directory exists and is empty. If it doesn't exist, try to
+// create it.
+bool IsDirectoryReadyExistedAndEmpty(char* dir_name);
+
+// A temporary directory where the new temp files created by GetTempFileName()
+// are written.
+CHAR kTempDirForGetTempFileName[] = "C:\\src\\TempDirGetTempFileName\\";
+
+// A temporary directory where the new temp files created by Guid-based method
+// are written.
+CHAR kTempDirForGuid[] = "C:\\src\\TempDirGuid\\";

[stanisc, 2017/04/14 18:45:59]

If you want to make the tool reusable it shouldn't rely on a predefined C:\src
directory. It could use either current directory or TEMP directory for the
output.

[chengx, 2017/04/14 22:27:22]

Thanks for the reminder. I have switched to the TEMP directory.

+
+// Maximum number of temp files allowed to create. This is limited by the
+// implementation of GetTempFileName().
+// "This limits GetTempFileName to a maximum of 65,535 unique file names if the
+// lpPathName and lpPrefixString parameters remain the same."
+// https://msdn.microsoft.com/en-us/library/windows/desktop/aa364991(v=vs.85).aspx
+UINT kMaxFileCreate = 65535;
+
+int main() {
+  UINT file_create_count;
+  std::string user_input;
+
+  while (true) {
+    std::cout << "\nPlease enter # of files to create (maximum "
+              << kMaxFileCreate << "), or \"quit\" to end the program : ";
+    std::getline(std::cin, user_input);
+
+    std::transform(user_input.begin(), user_input.end(), user_input.begin(),
+                   ::tolower);
+    if (user_input == "quit")
+      break;
+
+    std::cout << std::endl;
+    std::stringstream ss(user_input);
+
+    if (ss >> file_create_count && file_create_count <= kMaxFileCreate) {
+      std::cout << "\nPlease select method to create temp file names,\n"
+                << "\"t\" for GetTempFileName \n"
+                << "\"g\" for GUID-based \n"
+                << "\"b\" for both \n"
+                << "or \"quit\" to end the program : ";
+      std::getline(std::cin, user_input);
+
+      std::transform(user_input.begin(), user_input.end(), user_input.begin(),
+                     ::tolower);
+      if (user_input == "quit")
+        break;
+
+      if (user_input == "t" || user_input == "b") {
+        std::cout << "\nGetTempFileName :" << std::endl;
+        if (CreateFilesUsingGetTempFileName(file_create_count)) {
+          std::cout << "File creation succeeds at "
+                    << kTempDirForGetTempFileName
+                    << ", remember to clean all of them!" << std::endl;
+        }
+      }
+
+      if (user_input == "g" || user_input == "b") {
+        std::cout << "\nGUID-based :" << std::endl;
+        if (CreateFilesUsingGuid(file_create_count)) {
+          std::cout << "File creation succeeds at " << kTempDirForGuid
+                    << ", remember to clean all of them!" << std::endl;
+        }
+      }
+    } else {
+      std::cout << "Input number is invalid, please enter # of files to create "
+                   "(maximum "
+                << kMaxFileCreate << "), or \"quit\" to end the program : ";
+    }
+    std::cout << std::endl;
+  }
+  return 0;
+}
+
+bool CreateFilesUsingGuid(UINT count) {
+  if (!IsDirectoryReadyExistedAndEmpty(kTempDirForGuid))
+    return false;
+
+  LARGE_INTEGER starting_time, ending_time, elapsed_ms;
+  ::QueryPerformanceCounter(&starting_time);
+  LARGE_INTEGER frequency;
+  ::QueryPerformanceFrequency(&frequency);
+
+  for (UINT i = 1; i <= count; ++i) {
+    GUID guid;
+    HRESULT hCreateGuid = ::CoCreateGuid(&guid);
+    char buffer[37];
+    ConvertGuidToString(&guid, buffer);
+    std::string temp_name =
+        std::string(kTempDirForGuid).append(buffer).append(".tmp");
+
+    HANDLE file_handle =
+        ::CreateFileA(temp_name.c_str(), GENERIC_READ, FILE_SHARE_READ, NULL,
+                      CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
+    ::CloseHandle(file_handle);
+
+    if (i % 500 == 0 || i == count) {
+      ::QueryPerformanceCounter(&ending_time);
+      // Convert the elapsed number of ticks to milliseconds.
+      elapsed_ms.QuadPart = (ending_time.QuadPart - starting_time.QuadPart) *
+                            1000 / frequency.QuadPart;
+
+      starting_time = ending_time;
+      std::cout << i << " / " << count << " --- " << elapsed_ms.QuadPart
+                << " ms" << std::endl;
+    }
+  }
+  return true;
+}
+
+bool CreateFilesUsingGetTempFileName(UINT count) {
+  if (!IsDirectoryReadyExistedAndEmpty(kTempDirForGetTempFileName))
+    return false;
+
+  CHAR temp_name[MAX_PATH];
+  LARGE_INTEGER starting_time, ending_time, elapsed_ms;
+  ::QueryPerformanceCounter(&starting_time);
+  LARGE_INTEGER frequency;
+  ::QueryPerformanceFrequency(&frequency);
+
+  for (UINT i = 1; i <= count; ++i) {
+    ::GetTempFileNameA(kTempDirForGetTempFileName, "", 0, temp_name);
+    if (i % 500 == 0 || i == count) {
+      ::QueryPerformanceCounter(&ending_time);
+      // Convert the elapsed number of ticks to milliseconds.
+      elapsed_ms.QuadPart = (ending_time.QuadPart - starting_time.QuadPart) *
+                            1000 / frequency.QuadPart;
+
+      starting_time = ending_time;
+      std::cout << i << " / " << count << " --- " << elapsed_ms.QuadPart
+                << " ms" << std::endl;
+    }
+  }
+  return true;
+}
+
+char* ConvertGuidToString(const GUID* id, char* out) {
+  int i;
+  char* ret = out;
+  out += sprintf(out, "%.8lX-%.4hX-%.4hX-", id->Data1, id->Data2, id->Data3);
+  for (i = 0; i < sizeof(id->Data4); ++i) {
+    out += sprintf(out, "%.2hhX", id->Data4[i]);

[stanisc, 2017/04/14 18:46:00]

Could use cast Data4 to to avoid printing byte by byte.

[stanisc, 2017/04/14 18:47:58]

What I was really trying to say is: Could this try to cast Data4 to ULONGLONG to
avoid printing byte by byte?

[chengx, 2017/04/14 22:27:22]

Em, I am not sure but I will try. I think the current way is working fine
though.

+    if (i == 1)
+      *(out++) = '-';
+  }
+  return ret;
+}
+
+bool IsDirectoryReadyExistedAndEmpty(char* dir_name) {
+  if (::PathFileExistsA(dir_name)) {
+    if (!::PathIsDirectoryEmptyA(dir_name)) {
+      std::cout << dir_name
+                << " directory is not empty, please remove all its content.";
+      return false;
+    }
+    return true;
+  } else if (::CreateDirectoryA(dir_name, NULL) == 0) {
+    std::cout << dir_name << "directory creation fails.";
+    return false;
+  } else {
+    return true;
+  }
+}