Rust: windows-rs: SHGetLocalizedName() example

win_sh_get_localized_name.rs

const MAX_PATH_LEN: usize = 2048;

#[allow(overflowing_literals)]
const ERR_MOD_NOT_FOUND: windows::core::HRESULT = windows::core::HRESULT(0x8007007Ei32);

pub fn win_sh_get_localized_name(path: &str) -> anyhow::Result<String> {
    let path_hstr = windows::core::HSTRING::from(path);
    let mut res_path = Vec::with_capacity(MAX_PATH_LEN);
    unsafe { res_path.set_len(res_path.capacity()); }
    let mut res_id = 0i32;

    unsafe {
        windows::Win32::UI::Shell::SHGetLocalizedName(
            &path_hstr,
            res_path.as_mut_slice(),
            std::ptr::addr_of_mut!(res_id),
        )?;
    }

    let mod_path0 = windows::core::PCWSTR::from_raw(res_path.as_ptr());
    let mut mod_path = vec![];

    loop {
        let bytes_returned = unsafe {
            windows::Win32::System::Environment::ExpandEnvironmentStringsW(mod_path0, Some(mod_path.as_mut_slice()))
        };
        if bytes_returned == 0 {
            unsafe { windows::Win32::Foundation::GetLastError()?; }
            panic!("ExpandEnvironmentStringsW() returned 0 and GetLastError() returns 0");
        }
        if mod_path.len() >= bytes_returned as _ {
            break;
        }

        // If the function succeeds, the return value is the number of TCHARs stored in the destination buffer, including the terminating null character.
        // If the destination buffer is too small to hold the expanded string, the return value is the required buffer size, in characters.
        // https://learn.microsoft.com/en-us/windows/win32/api/processenv/nf-processenv-expandenvironmentstringsw#return-value
        mod_path.reserve(bytes_returned as usize - mod_path.len());
        unsafe { mod_path.set_len(mod_path.capacity()); }
    }

    let mod_path = windows::core::PCWSTR::from_raw(mod_path.as_ptr());
    let hmod = unsafe {
        match windows::Win32::System::LibraryLoader::LoadLibraryW(mod_path) {
            Ok(hmod) => hmod,
            Err(err) => {
                if err.code() == ERR_MOD_NOT_FOUND {
                    if res_id == 0 {
                        // C:\Users\nutstore\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\desktop.ini:
                        //  [LocalizedFileNames]
                        //  OneDrive.lnk=OneDrive
                        let localized_name = mod_path0.to_string()?;
                        if !localized_name.is_empty() {
                            return Ok(localized_name);
                        }
                    }
                }
                return Err(err.into());
            }
        }
    };

    // Must be of sufficient length to hold a pointer (8 bytes).
    // https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-loadstringw#parameters
    let mut buffer = Vec::with_capacity(8);

    loop {
        let bytes_returned = unsafe {
            windows::Win32::UI::WindowsAndMessaging::LoadStringW(
                hmod,
                res_id as _,
                windows::core::PWSTR::from_raw(buffer.as_mut_ptr()),
                buffer.len() as _,
            )
        };
        assert!(bytes_returned >= 0, "{}", bytes_returned);
        if bytes_returned == 0 {
            unsafe { windows::Win32::Foundation::GetLastError()?; }
            panic!("LoadLibraryW() returned 0 and GetLastError() returns 0");
        }
        if buffer.len() >= bytes_returned as _ {
            break;
        }

        // The number of characters in the string resource that lpBuffer points to (if cchBufferMax is zero).
        // The string resource is not guaranteed to be null-terminated in the module's resource table ...
        // https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-loadstringw#return-value
        buffer.reserve(bytes_returned as usize - buffer.len() + 1);
        unsafe { buffer.set_len(buffer.capacity()); }
        buffer.fill(0);
    }

    let localized_name = windows::core::PCWSTR::from_raw(buffer.as_ptr());
    let localized_name = unsafe { localized_name.to_string()? };
    Ok(localized_name)
}

fn main() -> Result<(), Box<dyn std::error::Error>> {
    //let input = r#"C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Accessories\Notepad.lnk"#;
    //let input = r#"C:\Users\nutstore\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\System Tools\File Explorer.lnk"#;
    let input = r#"C:\Users\nutstore\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\OneDrive.lnk"#;
    //let input = r#"C:\Users\nutstore\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Visual Studio Code\Visual Studio Code.lnk"#;
    //let input = r#"C:\Users\nutstore\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\回收站.lnk"#;
    println!(" Input: {}", input);

    let localized_name = win_sh_get_localized_name(input)?;
    println!("Output: {}", localized_name);

    Ok(())
}

$ ./rust-test.exe
 Input: C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Accessories\Notepad.lnk
Output: 记事本

If the localized name cannot be found or the path does not exist, the error would be:
Error: 系统找不到指定的文件。 (0x80070002 = -2147024894i32)