bin: implement “leds set” subcommand

Currently only supports setting the raw state from an integer
value:

    $ vtcol leds set -8 2

2 files changed, 61 insertions, 6 deletions

diff --git a/src/lib.rs b/src/lib.rs
index 2ef43e8..6193277 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -160,7 +160,7 @@ pub mod ioctl
     }
 }
 
-#[derive(Debug)]
+#[derive(Clone, Copy, Debug)]
 pub struct KbLedState(u8);
 
 impl KbLedState
@@ -180,6 +180,12 @@ impl KbLedState
     pub fn get(con: &Console) -> io::Result<Self> { ioctl::kdgetled(con) }
 
     #[inline]
+    pub fn set(&self, con: &Console) -> io::Result<()>
+    {
+        ioctl::kdsetled(con, Some(*self))
+    }
+
+    #[inline]
     pub fn cap(&self) -> bool { (self.0 & 0x4) != 0 }
 
     #[inline]
@@ -221,6 +227,26 @@ impl From<KbLedState> for u8
     fn from(state: KbLedState) -> Self { state.0 }
 }
 
+impl TryFrom<u8> for KbLedState
+{
+    type Error = io::Error;
+
+    fn try_from(val: u8) -> io::Result<Self>
+    {
+        if val <= 0b111 {
+            Ok(Self(val))
+        } else {
+            Err(io::Error::new(
+                io::ErrorKind::Other,
+                format!(
+                    "invalid raw led value: {:#b}; must not exceed 3 b",
+                    val
+                ),
+            ))
+        }
+    }
+}
+
 #[cfg(test)]
 mod kb_led_state
 {
diff --git a/src/vtcol.rs b/src/vtcol.rs
index e9f9c2b..2fdec10 100644
--- a/src/vtcol.rs
+++ b/src/vtcol.rs
@@ -24,7 +24,7 @@ enum LedJob
     /** Get keyboard LED state. */
     Get(bool),
     /** Set keyboard LED state. */
-    Set,
+    Set(KbLedState),
 }
 
 #[derive(Debug)]
@@ -212,15 +212,27 @@ impl<'a> Job
                     .about("operations regarding keyboard LEDs")
                     .subcommand(
                         SubCommand::with_name("get")
-                            .about("get keyboard LED state")
+                            .about("get LED state")
                             .arg(
                                 Arg::with_name("u8")
-                                    .value_name("NAME")
                                     .short("8")
                                     .long("u8")
                                     .help("output raw state as integer")
                                     .takes_value(false),
                             ),
+                    )
+                    .subcommand(
+                        SubCommand::with_name("set")
+                            .about("set LED state")
+                            .arg(
+                                Arg::with_name("u8")
+                                    .short("8")
+                                    .long("u8")
+                                    .help("provide desired state as integer")
+                                    .takes_value(true)
+                                    .required(true)
+                                    .value_name("STATE"),
+                            ),
                     ),
             );
 
@@ -336,6 +348,11 @@ impl<'a> Job
                         let raw = subm.is_present("u8");
                         Ok(Self::Leds(LedJob::Get(raw)))
                     },
+                    ("set", Some(subm)) => {
+                        let st: u8 = subm.value_of("u8").unwrap().parse()?;
+                        let st = KbLedState::try_from(st)?;
+                        Ok(Self::Leds(LedJob::Set(st)))
+                    },
                     (junk, _) =>
                         Err(anyhow!(
                             "invalid sub-subcommand to leds: [{}]; try ``{} \
@@ -413,7 +430,7 @@ impl<'a> Job
             Self::Colors(ColorJob::Fade(from, to, ms, hz, clear)) =>
                 Self::fade(from, to, ms, hz, clear)?,
             Self::Leds(LedJob::Get(raw)) => Self::get_leds(raw)?,
-            Self::Leds(LedJob::Set) => unimplemented!(),
+            Self::Leds(LedJob::Set(st)) => Self::set_leds(st)?,
         }
 
         Ok(())
@@ -490,7 +507,7 @@ impl<'a> Job
         Ok(())
     }
 
-    /** Get the keyboard led state. */
+    /** Get the keyboard LED state. */
     fn get_leds(raw: bool) -> Result<()>
     {
         let fd = Console::current()?;
@@ -506,6 +523,18 @@ impl<'a> Job
 
         Ok(())
     }
+
+    /** Set the keyboard LED state. */
+    fn set_leds(st: KbLedState) -> Result<()>
+    {
+        let fd = Console::current()?;
+        vrb!("console fd: {}", fd);
+
+        st.set(&fd)?;
+        vrb!("applied");
+
+        Ok(())
+    }
 } /* [impl Job] */
 
 fn main() -> Result<()>