Get all friendly monitor names (model number, brand) in Rust

windows_monitor_names.rs

use windows::Win32::Devices::Display::DISPLAYCONFIG_PATH_INFO;
use windows::Win32::{
    Devices::Display::{
        DisplayConfigGetDeviceInfo, GetDisplayConfigBufferSizes, QueryDisplayConfig,
        DISPLAYCONFIG_ADAPTER_NAME, DISPLAYCONFIG_DEVICE_INFO_GET_ADAPTER_NAME,
        DISPLAYCONFIG_DEVICE_INFO_GET_TARGET_NAME, DISPLAYCONFIG_MODE_INFO,
        DISPLAYCONFIG_TARGET_DEVICE_NAME, QDC_ONLY_ACTIVE_PATHS,
        QDC_VIRTUAL_MODE_AWARE,
    },
    Foundation::{ERROR_INSUFFICIENT_BUFFER, ERROR_SUCCESS, WIN32_ERROR},
};

// https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-querydisplayconfig#examples
pub unsafe fn get_monitor_names() -> Option<Vec<String>> {
    let mut names = vec![];

    let mut paths: Vec<DISPLAYCONFIG_PATH_INFO> = vec![];
    let mut modes: Vec<DISPLAYCONFIG_MODE_INFO> = vec![];
    let flags = QDC_ONLY_ACTIVE_PATHS | QDC_VIRTUAL_MODE_AWARE;
    let mut result;

    loop {
        let mut path_count: u32 = 0;
        let mut mode_count: u32 = 0;

        result = GetDisplayConfigBufferSizes(flags, &mut path_count, &mut mode_count);
        if result != ERROR_SUCCESS {
            return None;
        }

        paths.resize(
            path_count.try_into().unwrap(),
            DISPLAYCONFIG_PATH_INFO::default(),
        );
        modes.resize(
            mode_count.try_into().unwrap(),
            DISPLAYCONFIG_MODE_INFO::default(),
        );

        result = QueryDisplayConfig(
            flags,
            &mut path_count,
            paths.as_mut_ptr(),
            &mut mode_count,
            modes.as_mut_ptr(),
            None,
        );

        paths.resize(
            path_count.try_into().unwrap(),
            DISPLAYCONFIG_PATH_INFO::default(),
        );
        modes.resize(
            mode_count.try_into().unwrap(),
            DISPLAYCONFIG_MODE_INFO::default(),
        );

        if result != ERROR_INSUFFICIENT_BUFFER {
            break;
        }
    }

    if result != ERROR_SUCCESS {
        return None;
    }

    for path in paths {
        let mut target_name = DISPLAYCONFIG_TARGET_DEVICE_NAME::default();
        target_name.header.adapterId = path.targetInfo.adapterId;
        target_name.header.id = path.targetInfo.id;
        target_name.header.r#type = DISPLAYCONFIG_DEVICE_INFO_GET_TARGET_NAME;
        target_name.header.size = core::mem::size_of::<DISPLAYCONFIG_TARGET_DEVICE_NAME>() as u32;
        result = WIN32_ERROR(
            DisplayConfigGetDeviceInfo(&mut target_name.header)
                .try_into()
                .unwrap(),
        );
        if result.is_err() {
            return None;
        }

        let mut adapter_name = DISPLAYCONFIG_ADAPTER_NAME::default();
        adapter_name.header.adapterId = path.targetInfo.adapterId;
        adapter_name.header.r#type = DISPLAYCONFIG_DEVICE_INFO_GET_ADAPTER_NAME;
        adapter_name.header.size = core::mem::size_of::<DISPLAYCONFIG_ADAPTER_NAME>() as u32;
        result = WIN32_ERROR(
            DisplayConfigGetDeviceInfo(&mut adapter_name.header)
                .try_into()
                .unwrap(),
        );

        if result.is_err() {
            return None;
        }

        let dstr = widestring::U16String::from_vec(target_name.monitorFriendlyDeviceName)
            .to_string_lossy();
        names.push(dstr.trim_end_matches("\0").to_string());
    }

    Some(names)
}