test app to test file locking usecases

CMakeLists.txt

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+cmake_minimum_required(VERSION 3.10)
+
+ADD_DEFINITIONS(-DUNICODE)
+ADD_DEFINITIONS(-D_UNICODE)
+
+file(GLOB SOURCES "*.cpp")
+
+project(file_blocker_tester)
+add_executable(file_blocker_tester ${SOURCES} )
+
+if(WIN32)
+   set_target_properties(file_blocker_tester PROPERTIES LINK_FLAGS_DEBUG "/SUBSYSTEM:CONSOLE")
+   set_target_properties(file_blocker_tester PROPERTIES COMPILE_DEFINITIONS_DEBUG "_CONSOLE")
+   set_target_properties(file_blocker_tester PROPERTIES LINK_FLAGS_RELWITHDEBINFO "/SUBSYSTEM:CONSOLE")
+   set_target_properties(file_blocker_tester PROPERTIES COMPILE_DEFINITIONS_RELWITHDEBINFO "_CONSOLE")
+   set_target_properties(file_blocker_tester PROPERTIES LINK_FLAGS_RELEASE "/SUBSYSTEM:CONSOLE")
+   set_target_properties(file_blocker_tester PROPERTIES LINK_FLAGS_MINSIZEREL "/SUBSYSTEM:CONSOLE")
+endif(WIN32)
+
+set_property(DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR} PROPERTY VS_STARTUP_PROJECT file_blocker_tester)

README.md

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+# file-blocker
+Simple console app that can be used to test use case when file access blocked by other process. 
+
+
+## Build 
+```
+mkdir build 
+cd build 
+cmake -G "Visual Studio 15 2017 Win64"  ../   
+cmake --build . --target ALL_BUILD --config Release -- /p:CharacterSet=Unicode
+```
+
+## Running 
+
+This app block itself. 
+
+When run without params it just runs and that block file from being rewriten or deleted. 
+
+When run with first param `-l` it will try to get exclusive access to itself with `LockFileEx` so no other app can even read that file. 

file_blocker.cpp

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+// file_blocker.cpp : This file contains the 'main' function. Program execution begins and ends there.
+//
+
+#include <iostream>
+#include <string>
+#include <Windows.h>
+
+bool use_extended_locking = false;
+
+int main(int argc, char * argv[])
+{
+	HANDLE h_file = 0;	
+	BOOL lock_success = false;
+	std::cout << "Hello there! Gonna lock this file\n";
+
+	if (argc >= 2)
+	{
+		std::string first_param(argv[1]);
+		if (first_param.compare("-l") == 0)
+		{
+			use_extended_locking = true;
+		}
+	}
+
+	if (use_extended_locking)
+	{
+		wchar_t app_path_buffer[MAX_PATH + 1];
+		if (GetModuleFileName(NULL, app_path_buffer, MAX_PATH) == 0)
+		{
+			std::cout << "Error: Failed get file path\n";
+			return;
+		}
+
+		std::wstring app_path_wstring = app_path_buffer;
+		std::cout << "Run file: \"" << std::string(app_path_wstring.begin(), app_path_wstring.end()) << "\" (only block writing and deleting )\n";
+
+		OVERLAPPED overlapvar = { 0 };
+
+		std::cout << "Lock file: \"" << std::string(app_path_wstring.begin(), app_path_wstring.end()) << "\" (block reading too)\n";
+
+		h_file = CreateFile(app_path_buffer, GENERIC_READ, 0, NULL, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
+		if (h_file)
+		{
+			lock_success = LockFileEx(h_file, LOCKFILE_EXCLUSIVE_LOCK | LOCKFILE_FAIL_IMMEDIATELY, 0, MAXDWORD, MAXDWORD, &overlapvar);
+			if (!lock_success)
+			{
+				std::cout << "Error: Failed to lock file\n";
+			}
+		}
+		else {
+			std::cout << "Error: Failed to lock file\n";
+		}
+	}
+
+	while (1)
+	{
+		Sleep(500);
+		std::cout << "Still blocking file: \"" << argv[0] << "\"\n";
+	}
+
+	CloseHandle(h_file);
+}
+