V2: Make desktop_env() return an Option (#125)

examples/whoami-demo.rs

@@ -39,7 +39,9 @@ fn main() {
     );
     println!(
         "Device's Desktop Env.  whoami::desktop_env():         {}",
-        whoami::desktop_env(),
+        whoami::desktop_env()
+            .map(|e| e.to_string())
+            .unwrap_or_else(|| "<unknown>".to_string()),
     );
     println!(
         "Device's CPU Arch      whoami::arch():                {}",

src/api.rs

@@ -1,4 +1,4 @@
-use std::ffi::OsString;
+use std::{env, ffi::OsString};
 
 use crate::{
     conversions,
@@ -104,11 +104,21 @@ pub fn distro() -> Result<String> {
     Target::distro(Os)
 }
 
-/// Get the desktop environment.
+/// Get the desktop environment (if any).
 ///
 /// Example: "gnome" or "windows"
+///
+/// Returns `None` if a desktop environment is not available (for example in a
+/// TTY or over SSH)
 #[inline(always)]
-pub fn desktop_env() -> DesktopEnv {
+pub fn desktop_env() -> Option<DesktopEnv> {
+    if env::var_os("SSH_CLIENT").is_some()
+        || env::var_os("SSH_TTY").is_some()
+        || env::var_os("SSH_CONNECTION").is_some()
+    {
+        return None;
+    }
+
     Target::desktop_env(Os)
 }
 

src/lib.rs

@@ -47,7 +47,9 @@
 //! );
 //! println!(
 //!     "Device's Desktop Env.  whoami::desktop_env():         {}",
-//!     whoami::desktop_env(),
+//!     whoami::desktop_env()
+//!         .map(|e| e.to_string())
+//!         .unwrap_or_else(|| "<unknown>".to_string()),
 //! );
 //! println!(
 //!     "Device's CPU Arch      whoami::arch():                {}",

src/os.rs

@@ -72,7 +72,7 @@ pub(crate) trait Target: Sized {
     /// Return the OS distribution's name.
     fn distro(self) -> Result<String>;
     /// Return the desktop environment.
-    fn desktop_env(self) -> DesktopEnv;
+    fn desktop_env(self) -> Option<DesktopEnv>;
     /// Return the target platform.
     fn platform(self) -> Platform;
     /// Return the computer's CPU architecture.

src/os/daku.rs

@@ -42,8 +42,8 @@ impl Target for Os {
     }
 
     #[inline(always)]
-    fn desktop_env(self) -> DesktopEnv {
-        DesktopEnv::Unknown("Unknown Daku".to_string())
+    fn desktop_env(self) -> Option<DesktopEnv> {
+        None
     }
 
     #[inline(always)]

src/os/redox.rs

@@ -130,8 +130,8 @@ impl Target for Os {
     }
 
     #[inline(always)]
-    fn desktop_env(self) -> DesktopEnv {
-        DesktopEnv::Orbital
+    fn desktop_env(self) -> Option<DesktopEnv> {
+        Some(DesktopEnv::Orbital)
     }
 
     #[inline(always)]

src/os/target.rs

@@ -44,8 +44,8 @@ impl Target for Os {
     }
 
     #[inline(always)]
-    fn desktop_env(self) -> DesktopEnv {
-        DesktopEnv::Unknown("Unknown".to_string())
+    fn desktop_env(self) -> Option<DesktopEnv> {
+        None
     }
 
     #[inline(always)]

src/os/unix.rs

@@ -8,6 +8,15 @@
     target_os = "hurd",
 ))]
 use std::env;
+#[cfg(target_os = "macos")]
+use std::{
+    ffi::OsStr,
+    os::{
+        raw::{c_long, c_uchar},
+        unix::ffi::OsStrExt,
+    },
+    ptr::null_mut,
+};
 use std::{
     ffi::{c_void, CStr, OsString},
     fs,
@@ -19,14 +28,6 @@ use std::{
     },
     slice,
 };
-#[cfg(target_os = "macos")]
-use std::{
-    os::{
-        raw::{c_long, c_uchar},
-        unix::ffi::OsStrExt,
-    },
-    ptr::null_mut,
-};
 
 use crate::{
     os::{Os, Target},
@@ -589,11 +590,10 @@ impl Target for Os {
         }
     }
 
-    fn desktop_env(self) -> DesktopEnv {
+    fn desktop_env(self) -> Option<DesktopEnv> {
         #[cfg(target_os = "macos")]
-        let env = "Aqua";
+        let env = OsStr::new("Aqua");
 
-        // FIXME: use `let else`
         #[cfg(any(
             target_os = "linux",
             target_os = "dragonfly",
@@ -603,23 +603,12 @@ impl Target for Os {
             target_os = "illumos",
             target_os = "hurd",
         ))]
-        let env = env::var_os("DESKTOP_SESSION");
-        #[cfg(any(
-            target_os = "linux",
-            target_os = "dragonfly",
-            target_os = "freebsd",
-            target_os = "netbsd",
-            target_os = "openbsd",
-            target_os = "illumos",
-            target_os = "hurd",
-        ))]
-        let env = if let Some(ref env) = env {
-            env.to_string_lossy()
-        } else {
-            return DesktopEnv::Unknown("Unknown".to_string());
-        };
+        let env = env::var_os("DESKTOP_SESSION")?;
 
-        if env.eq_ignore_ascii_case("AQUA") {
+        // convert `OsStr` to `Cow`
+        let env = env.to_string_lossy();
+
+        Some(if env.eq_ignore_ascii_case("AQUA") {
             DesktopEnv::Aqua
         } else if env.eq_ignore_ascii_case("GNOME") {
             DesktopEnv::Gnome
@@ -636,7 +625,7 @@ impl Target for Os {
         // TODO: Other Linux Desktop Environments
         } else {
             DesktopEnv::Unknown(env.to_string())
-        }
+        })
     }
 
     #[inline(always)]

src/os/wasi.rs

@@ -45,12 +45,9 @@ impl Target for Os {
     }
 
     #[inline(always)]
-    fn desktop_env(self) -> DesktopEnv {
-        if let Some(ref env) = env::var_os("DESKTOP_SESSION") {
-            DesktopEnv::Unknown(env.to_string_lossy().to_string())
-        } else {
-            DesktopEnv::Unknown("Unknown WASI".to_string())
-        }
+    fn desktop_env(self) -> Option<DesktopEnv> {
+        env::var_os("DESKTOP_SESSION")
+            .map(|env| DesktopEnv::Unknown(env.to_string_lossy().to_string()))
     }
 
     #[inline(always)]

src/os/web.rs

@@ -160,8 +160,8 @@ impl Target for Os {
     }
 
     #[inline(always)]
-    fn desktop_env(self) -> DesktopEnv {
-        DesktopEnv::WebBrowser
+    fn desktop_env(self) -> Option<DesktopEnv> {
+        Some(DesktopEnv::WebBrowser)
     }
 
     fn platform(self) -> Platform {

src/os/windows.rs

@@ -385,8 +385,8 @@ impl Target for Os {
     }
 
     #[inline(always)]
-    fn desktop_env(self) -> DesktopEnv {
-        DesktopEnv::Windows
+    fn desktop_env(self) -> Option<DesktopEnv> {
+        Some(DesktopEnv::Windows)
     }
 
     #[inline(always)]