openorclosefilemappingA

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/datastores/sharedmemory/SharedMemory.cpp

@@ -0,0 +1,86 @@
+#include "SharedMemory.h"
+#include "Config.h"
+
+bool SharedMemory::createOrOpenMapping(MappingInfo& mapping)
+{
+    if (mapping.recordSize == 0)
+    {
+        return false;
+    }
+    mapping.fileHandle =
+        CreateFileA(
+            mapping.fileName.c_str(),
+            GENERIC_READ | GENERIC_WRITE,
+            FILE_SHARE_READ | FILE_SHARE_WRITE,
+            NULL,
+            OPEN_ALWAYS,
+            FILE_ATTRIBUTE_NORMAL,
+            NULL);
+    if (mapping.fileHandle == INVALID_HANDLE_VALUE)
+    {
+        return false;
+    }
+    LARGE_INTEGER fileSize;
+    if (!GetFileSizeEx(mapping.fileHandle, &fileSize))
+    {
+        CloseHandle(mapping.fileHandle);
+        mapping.fileHandle = INVALID_HANDLE_VALUE;
+        return false;
+    }
+    bool isNewFile = (fileSize.QuadPart == 0);
+    const size_t initialCapacity = config::file::INITIAL_CAPACITY;
+    if (isNewFile)
+    {
+        LARGE_INTEGER newSize;
+        newSize.QuadPart = sizeof(FileHeader) + initialCapacity * mapping.recordSize;
+        if (!SetFilePointerEx(mapping.fileHandle, newSize, NULL, FILE_BEGIN))
+        {
+            CloseHandle(mapping.fileHandle);
+            mapping.fileHandle = INVALID_HANDLE_VALUE;
+            return false;
+        }
+        if (!SetEndOfFile(mapping.fileHandle))
+        {
+            CloseHandle(mapping.fileHandle);
+            mapping.fileHandle = INVALID_HANDLE_VALUE;
+            return false;
+        }
+    }
+    mapping.mappingHandle =
+        CreateFileMappingA(
+            mapping.fileHandle,
+            NULL,
+            PAGE_READWRITE,
+            0,
+            0,
+            NULL);
+    if (mapping.mappingHandle == NULL)
+    {
+        CloseHandle(mapping.fileHandle);
+        mapping.fileHandle = INVALID_HANDLE_VALUE;
+        return false;
+    }
+    mapping.mappedView =
+        MapViewOfFile(
+            mapping.mappingHandle,
+            FILE_MAP_ALL_ACCESS,
+            0,
+            0,
+            0);
+    if (mapping.mappedView == nullptr)
+    {
+        CloseHandle(mapping.mappingHandle);
+        CloseHandle(mapping.fileHandle);
+        mapping.mappingHandle = NULL;
+        mapping.fileHandle = INVALID_HANDLE_VALUE;
+        return false;
+    }
+    FileHeader* header = reinterpret_cast<FileHeader*>(mapping.mappedView);
+    if (isNewFile)
+    {
+        header->recordCount = 0;
+        header->capacity = initialCapacity;
+    }
+    mapping.mappedCapacity = header->capacity;
+    return true;
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/Config.h

@@ -28,6 +28,7 @@ namespace config
 
 	namespace file
 	{
+		const size_t INITIAL_CAPACITY = 100;
 		constexpr const char* INVENTORYITEM_FILE = "files/InventoryItem.csv";
 		constexpr const char* USER_FILE = "files/User.csv";
 		constexpr const char* NOTIFICATION_FILE = "files/Notification.csv";