Ely Office: six offline-first desktop apps in Rust and GPUI

ElyDoc, ElyTable, ElyShow (LibreOfficeKit), ElyPDF (MuPDF), ElyTree (Git),
ElyMark (Milkdown and CodeMirror in CEF). ElyMail and ElyAgent follow.

crates/ely-platform/src/user.rs

@@ -0,0 +1,68 @@
+//! The name documents sign new comments and changes with.
+
+use std::io;
+
+/// The author name from settings, else the account's.
+pub fn name() -> io::Result<String> {
+    let set = crate::settings::Shared::load()?.author;
+    if !set.is_empty() {
+        return Ok(set);
+    }
+    account()
+}
+
+/// The account's full name, else its login name.
+pub fn account() -> io::Result<String> {
+    let full = full_name()?;
+    if !full.trim().is_empty() {
+        return Ok(full.trim().to_string());
+    }
+    let key = if cfg!(windows) { "USERNAME" } else { "USER" };
+    log::info!("user: no full name; the login name signs");
+    std::env::var(key).map_err(|error| io::Error::other(format!("no {key}: {error}")))
+}
+
+#[cfg(target_os = "macos")]
+fn full_name() -> io::Result<String> {
+    Ok(objc2_foundation::NSFullUserName().to_string())
+}
+
+#[cfg(target_os = "linux")]
+fn full_name() -> io::Result<String> {
+    // The first comma field of the passwd comment.
+    let entry = unsafe { libc::getpwuid(libc::getuid()) };
+    if entry.is_null() {
+        return Err(io::Error::last_os_error());
+    }
+    let gecos = unsafe { (*entry).pw_gecos };
+    if gecos.is_null() {
+        return Ok(String::new());
+    }
+    let text = unsafe { std::ffi::CStr::from_ptr(gecos) }.to_string_lossy();
+    Ok(text.split(',').next().unwrap_or_default().to_string())
+}
+
+#[cfg(windows)]
+fn full_name() -> io::Result<String> {
+    use windows_sys::Win32::Security::Authentication::Identity::{GetUserNameExW, NameDisplay};
+    let mut size = 0u32;
+    unsafe { GetUserNameExW(NameDisplay, std::ptr::null_mut(), &mut size) };
+    // Accounts outside a domain have no display name.
+    if size == 0 {
+        return Ok(String::new());
+    }
+    let mut buffer = vec![0u16; size as usize];
+    if unsafe { GetUserNameExW(NameDisplay, buffer.as_mut_ptr(), &mut size) } == 0 {
+        return Err(io::Error::last_os_error());
+    }
+    Ok(String::from_utf16_lossy(&buffer[..size as usize]))
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn the_account_has_a_name() {
+        let name = super::name().expect("a name");
+        assert!(!name.is_empty());
+    }
+}