Use CLI11 to parse command line options

This has a few advantages over the previous manual approach:

- The option parsing is handled by the library, so it doesn't need to be
  done manually.
- More detailed help usage is now shown when passing the -h/--help flag.
  Information about each of the available options is shown.
- Options can be marked as mutually exclusive. This is done with the
  --remove_as_default and --set_as_default flags, for example.
- Options can be passed in in windows style (e.g. /help).
- Although not used at the moment, the library also offers other
  features, such as the ability to validate and transform input values.

Documentation/User/History.txt

@@ -88,6 +88,10 @@ Misc:
 - Builds are now digitally signed.
 - All menus are now drawn in the standard system style, rather
   than a custom style.
+- More detailed help information is now available when starting
+  Explorer++ from the command line with the --help flag. Each of
+  the available options is listed and briefly described. The
+  names of some of the options have also been updated.
 - The format used to display dates has been updated. Previously,
   the date and time were separated by a comma. Now, they're
   separated by a space.

Explorer++/Explorer++/CommandLine.cpp

@@ -0,0 +1,226 @@
+// Copyright (C) Explorer++ Project
+// SPDX-License-Identifier: GPL-3.0-only
+// See LICENSE in the top level directory
+
+#include "stdafx.h"
+#include "CommandLine.h"
+#include "Explorer++_internal.h"
+#include "MainResource.h"
+#include "../Helper/Macros.h"
+#include "../Helper/ProcessHelper.h"
+#include "../Helper/SetDefaultFileManager.h"
+#include "../Helper/ShellHelper.h"
+#include "../Helper/StringHelper.h"
+#include "../ThirdParty/CLI11/CLI11.hpp"
+#include <boost/filesystem.hpp>
+#include <boost/log/core.hpp>
+
+extern std::vector<std::wstring> g_TabDirs;
+
+struct CommandLineSettings
+{
+	bool clearRegistrySettings;
+	bool enableLogging;
+	bool enablePlugins;
+	bool removeAsDefault;
+	bool setAsDefault;
+	std::string language;
+	bool jumplistNewTab;
+	std::vector<std::string> directories;
+};
+
+boost::optional<CommandLine::ExitInfo> ProcessCommandLineSettings(const CommandLineSettings& commandLineSettings);
+void OnClearRegistrySettings();
+void OnRemoveAsDefault();
+void OnSetAsDefault();
+void OnJumplistNewTab();
+
+boost::optional<CommandLine::ExitInfo> CommandLine::ProcessCommandLine()
+{
+	CLI::App app("Explorer++");
+
+	CommandLineSettings commandLineSettings;
+
+	commandLineSettings.clearRegistrySettings = false;
+	app.add_flag("--clear-registry-settings", commandLineSettings.clearRegistrySettings, "Clear existing registry settings");
+
+	commandLineSettings.enableLogging = false;
+	app.add_flag("--enable-logging", commandLineSettings.enableLogging, "Enable logging");
+
+	commandLineSettings.enablePlugins = false;
+	app.add_flag("--enable-plugins", commandLineSettings.enablePlugins, "Enable the Lua plugin system");
+
+	commandLineSettings.removeAsDefault = false;
+	auto removeAsDefaultOption = app.add_flag("--remove-as-default", commandLineSettings.removeAsDefault, "Remove Explorer++ as the default file manager (requires administrator privileges)");
+
+	commandLineSettings.setAsDefault = false;
+	auto setAsDefaultOption = app.add_flag("--set-as-default", commandLineSettings.setAsDefault, "Set Explorer++ as the default file manager (requires administrator privileges)");
+
+	removeAsDefaultOption->excludes(setAsDefaultOption);
+	setAsDefaultOption->excludes(removeAsDefaultOption);
+
+	app.add_option("--language", commandLineSettings.language, "Allows you to select your desired language. Should be a two-letter language code (e.g. FR, RU, etc).");
+
+	app.add_option("directories", commandLineSettings.directories, "Directories to open");
+
+	// The options in this group are only used internally by the
+	// application. They're not directly exposed to users.
+	CLI::App *privateCommands = app.add_subcommand("private");
+	privateCommands->group("");
+
+	privateCommands->add_flag(wstrToStr(NExplorerplusplus::JUMPLIST_TASK_NEWTAB_ARGUMENT), commandLineSettings.jumplistNewTab);
+
+	try
+	{
+		app.parse(__argc, __argv);
+	}
+	catch (const CLI::ParseError & e)
+	{
+		return ExitInfo{ app.exit(e) };
+	}
+
+	return ProcessCommandLineSettings(commandLineSettings);
+}
+
+boost::optional<CommandLine::ExitInfo> ProcessCommandLineSettings(const CommandLineSettings& commandLineSettings)
+{
+	if (commandLineSettings.jumplistNewTab)
+	{
+		OnJumplistNewTab();
+		return CommandLine::ExitInfo{ EXIT_SUCCESS };
+	}
+
+	if (commandLineSettings.clearRegistrySettings)
+	{
+		OnClearRegistrySettings();
+	}
+
+	if (commandLineSettings.enableLogging)
+	{
+		boost::log::core::get()->set_logging_enabled(true);
+	}
+
+	if (commandLineSettings.enablePlugins)
+	{
+		g_enablePlugins = true;
+	}
+
+	if (commandLineSettings.removeAsDefault)
+	{
+		OnRemoveAsDefault();
+	}
+	else if (commandLineSettings.setAsDefault)
+	{
+		OnSetAsDefault();
+	}
+
+	if (!commandLineSettings.language.empty())
+	{
+		g_bForceLanguageLoad = TRUE;
+
+		StringCchCopy(g_szLang, SIZEOF_ARRAY(g_szLang), strToWstr(commandLineSettings.language).c_str());
+	}
+
+	TCHAR processImageName[MAX_PATH];
+	GetProcessImageName(GetCurrentProcessId(), processImageName, SIZEOF_ARRAY(processImageName));
+
+	boost::filesystem::path processDirectoryPath(processImageName);
+	processDirectoryPath.remove_filename();
+
+	for (const std::string& directory : commandLineSettings.directories)
+	{
+		TCHAR szParsingPath[MAX_PATH];
+		DecodePath(strToWstr(directory).c_str(), processDirectoryPath.wstring().c_str(), szParsingPath, SIZEOF_ARRAY(szParsingPath));
+
+		g_TabDirs.push_back(szParsingPath);
+	}
+
+	return boost::none;
+}
+
+void OnClearRegistrySettings()
+{
+	LSTATUS lStatus;
+
+	lStatus = SHDeleteKey(HKEY_CURRENT_USER, NExplorerplusplus::REG_MAIN_KEY);
+
+	if (lStatus == ERROR_SUCCESS)
+		MessageBox(NULL, _T("Settings cleared successfully."), NExplorerplusplus::APP_NAME, MB_OK);
+	else
+		MessageBox(NULL, _T("Settings could not be cleared."), NExplorerplusplus::APP_NAME, MB_ICONWARNING);
+}
+
+void OnRemoveAsDefault()
+{
+	BOOL bSuccess = NDefaultFileManager::RemoveAsDefaultFileManagerFileSystem(SHELL_DEFAULT_INTERNAL_COMMAND_NAME);
+
+	/* Language hasn't been fully specified at this point, so
+	can't load success/error message from language dll. Simply show
+	a hardcoded success/error message. */
+	if (bSuccess)
+	{
+		MessageBox(NULL, _T("Explorer++ successfully removed as default file manager."),
+			NExplorerplusplus::APP_NAME, MB_OK);
+	}
+	else
+	{
+		MessageBox(NULL, _T("Could not remove Explorer++ as default file manager. Please \
+ensure you have administrator privileges."), NExplorerplusplus::APP_NAME, MB_ICONWARNING | MB_OK);
+	}
+}
+
+void OnSetAsDefault()
+{
+	TCHAR menuText[256];
+	LoadString(GetModuleHandle(0), IDS_OPEN_IN_EXPLORERPLUSPLUS,
+		menuText, SIZEOF_ARRAY(menuText));
+
+	BOOL bSuccess = NDefaultFileManager::SetAsDefaultFileManagerFileSystem(
+		SHELL_DEFAULT_INTERNAL_COMMAND_NAME, menuText);
+
+	if (bSuccess)
+	{
+		MessageBox(NULL, _T("Explorer++ successfully set as default file manager."),
+			NExplorerplusplus::APP_NAME, MB_OK);
+	}
+	else
+	{
+		MessageBox(NULL, _T("Could not set Explorer++ as default file manager. Please \
+ensure you have administrator privileges."), NExplorerplusplus::APP_NAME, MB_ICONWARNING | MB_OK);
+	}
+}
+
+void OnJumplistNewTab()
+{
+	/* This will be called when the user clicks the
+	'New Tab' item on the tasks menu in Windows 7 and above.
+	Find the already opened version of Explorer++,
+	and tell it to open a new tab. */
+	HANDLE hMutex;
+
+	hMutex = CreateMutex(NULL, TRUE, _T("Explorer++"));
+
+	if (GetLastError() == ERROR_ALREADY_EXISTS)
+	{
+		HWND hPrev;
+
+		hPrev = FindWindow(NExplorerplusplus::CLASS_NAME, NULL);
+
+		if (hPrev != NULL)
+		{
+			COPYDATASTRUCT cds;
+
+			cds.cbData = 0;
+			cds.lpData = NULL;
+			SendMessage(hPrev, WM_COPYDATA, NULL, (LPARAM)& cds);
+
+			SetForegroundWindow(hPrev);
+			ShowWindow(hPrev, SW_SHOW);
+		}
+	}
+
+	if (hMutex != NULL)
+	{
+		CloseHandle(hMutex);
+	}
+}

Explorer++/Explorer++/CommandLine.h

@@ -0,0 +1,17 @@
+// Copyright (C) Explorer++ Project
+// SPDX-License-Identifier: GPL-3.0-only
+// See LICENSE in the top level directory
+
+#pragma once
+
+#include <boost/optional.hpp>
+
+namespace CommandLine
+{
+	struct ExitInfo
+	{
+		int exitCode;
+	};
+
+	boost::optional<ExitInfo> ProcessCommandLine();
+}

Explorer++/Explorer++/Console.cpp

@@ -0,0 +1,104 @@
+// Copyright (C) Explorer++ Project
+// SPDX-License-Identifier: GPL-3.0-only
+// See LICENSE in the top level directory
+
+#include "stdafx.h"
+#include "Console.h"
+#include <iostream>
+
+bool RedirectConsoleIO();
+
+// The code in this file has been sourced from the following Stack Overflow
+// answer:
+// https://stackoverflow.com/a/55875595
+// It doesn't make much sense to rewrite it, given that it's relatively simple
+// and performs a specific function (so any rewritten code would look about the
+// same).
+
+bool Console::AttachParentConsole()
+{
+	bool result = false;
+
+	// Release any current console and redirect IO to NUL
+	ReleaseConsole();
+
+	// Attempt to attach to parent process's console
+	if (AttachConsole(ATTACH_PARENT_PROCESS))
+	{
+		result = RedirectConsoleIO();
+	}
+
+	return result;
+}
+
+bool Console::ReleaseConsole()
+{
+	bool result = true;
+	FILE* fp;
+
+	// Just to be safe, redirect standard IO to NUL before releasing.
+
+	// Redirect STDIN to NUL
+	if (freopen_s(&fp, "NUL:", "r", stdin) != 0)
+		result = false;
+	else
+		setvbuf(stdin, NULL, _IONBF, 0);
+
+	// Redirect STDOUT to NUL
+	if (freopen_s(&fp, "NUL:", "w", stdout) != 0)
+		result = false;
+	else
+		setvbuf(stdout, NULL, _IONBF, 0);
+
+	// Redirect STDERR to NUL
+	if (freopen_s(&fp, "NUL:", "w", stderr) != 0)
+		result = false;
+	else
+		setvbuf(stderr, NULL, _IONBF, 0);
+
+	// Detach from console
+	if (!FreeConsole() || !result)
+		return false;
+
+	return true;
+}
+
+bool RedirectConsoleIO()
+{
+	bool result = true;
+	FILE* fp;
+
+	// Redirect STDIN if the console has an input handle
+	if (GetStdHandle(STD_INPUT_HANDLE) != INVALID_HANDLE_VALUE)
+		if (freopen_s(&fp, "CONIN$", "r", stdin) != 0)
+			result = false;
+		else
+			setvbuf(stdin, NULL, _IONBF, 0);
+
+	// Redirect STDOUT if the console has an output handle
+	if (GetStdHandle(STD_OUTPUT_HANDLE) != INVALID_HANDLE_VALUE)
+		if (freopen_s(&fp, "CONOUT$", "w", stdout) != 0)
+			result = false;
+		else
+			setvbuf(stdout, NULL, _IONBF, 0);
+
+	// Redirect STDERR if the console has an error handle
+	if (GetStdHandle(STD_ERROR_HANDLE) != INVALID_HANDLE_VALUE)
+		if (freopen_s(&fp, "CONOUT$", "w", stderr) != 0)
+			result = false;
+		else
+			setvbuf(stderr, NULL, _IONBF, 0);
+
+	// Make C++ standard streams point to console as well.
+	std::ios::sync_with_stdio(true);
+
+	// Clear the error state for each of the C++ standard streams.
+	std::wcout.clear();
+	std::cout.clear();
+	std::wcerr.clear();
+	std::cerr.clear();
+	std::wcin.clear();
+	std::cin.clear();
+
+	return result;
+}

Explorer++/Explorer++/Console.h

@@ -0,0 +1,11 @@
+// Copyright (C) Explorer++ Project
+// SPDX-License-Identifier: GPL-3.0-only
+// See LICENSE in the top level directory
+
+#pragma once
+
+namespace Console
+{
+	bool AttachParentConsole();
+	bool ReleaseConsole();
+}

Explorer++/Explorer++/Explorer++.vcxproj

@@ -319,6 +319,8 @@
     <ClCompile Include="ColorRuleDialog.cpp" />
     <ClCompile Include="ColorRuleHelper.cpp" />
     <ClCompile Include="CommandInvoked.cpp" />
+    <ClCompile Include="CommandLine.cpp" />
+    <ClCompile Include="Console.cpp" />
     <ClCompile Include="CustomizeColorsDialog.cpp" />
     <ClCompile Include="DestroyFilesDialog.cpp" />
     <ClCompile Include="DialogHelper.cpp" />
@@ -449,6 +451,8 @@
     <ClInclude Include="ColorRuleDialog.h" />
     <ClInclude Include="ColorRuleHelper.h" />
     <ClInclude Include="CommandInvoked.h" />
+    <ClInclude Include="CommandLine.h" />
+    <ClInclude Include="Console.h" />
     <ClInclude Include="CoreInterface.h" />
     <ClInclude Include="CustomizeColorsDialog.h" />
     <ClInclude Include="DefaultColumns.h" />