Function tailFileW

RedEdr/logreader.cpp:22–81

Stupid but working tail-f implementation Just checks every second for new data

// Stupid but working tail-f implementation
// Just checks every second for new data
void tailFileW(const wchar_t* filePath) {
    LOG_A(LOG_INFO, "LOG: Tail -f %ls", filePath);

    HANDLE hFile = CreateFileW(filePath, GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
    if (hFile == INVALID_HANDLE_VALUE) {
        LOG_A(LOG_ERROR, "LOG: Failed to open file. Error: %lu", GetLastError());
        return;
    }

    // Buffer for reading the file
    const DWORD bufferSize = 1024;
    wchar_t buffer[bufferSize / sizeof(wchar_t)];
    DWORD bytesRead;
    LARGE_INTEGER fileSize;
    LARGE_INTEGER offset;

    // Get the file size
    if (!GetFileSizeEx(hFile, &fileSize)) {
        LOG_A(LOG_ERROR, "LOG: Failed to get file size. Error: %lu", GetLastError());
        CloseHandle(hFile);
        return;
    }

    // Start reading from the end of the file
    offset.QuadPart = fileSize.QuadPart;
    while (!LogReaderThreadStopFlag) {
        // Check if there's new data
        LARGE_INTEGER newSize;
        if (!GetFileSizeEx(hFile, &newSize)) {
            LOG_A(LOG_ERROR, "LOG: Failed to get file size. Error: %lu", GetLastError());
            break;
        }

        if (newSize.QuadPart > offset.QuadPart) {
            // Move the file pointer to the last read position
            SetFilePointerEx(hFile, offset, NULL, FILE_BEGIN);

            // Read the new data
            if (!ReadFile(hFile, buffer, bufferSize - sizeof(wchar_t), &bytesRead, NULL)) {
                LOG_A(LOG_INFO, "LOG: Failed to read file. Error: %lu", GetLastError());
                break;
            }

            // Null-terminate the buffer
            buffer[bytesRead / sizeof(wchar_t)] = L'\0';

            // Print the new data (including newline?)
            g_EventAggregator.do_output(std::wstring(buffer));
            //wprintf(L"%s", buffer);

            // Update the offset
            offset.QuadPart += bytesRead;
        }

        // Sleep for a while before checking again
        Sleep(1000);
    }