tape: cleanup LinuxDriveStatus - make density optional

src/api2/types/tape/drive.rs

@@ -117,8 +117,6 @@ pub struct MamAttribute {
 #[api()]
 #[derive(Serialize,Deserialize,Copy,Clone,Debug)]
 pub enum TapeDensity {
-    /// No tape loaded
-    None,
     /// LTO1
     LTO1,
     /// LTO2
@@ -144,7 +142,6 @@ impl TryFrom<u8> for TapeDensity {
 
     fn try_from(value: u8) -> Result<Self, Self::Error> {
         let density = match value {
-            0x00 => TapeDensity::None,
             0x40 => TapeDensity::LTO1,
             0x42 => TapeDensity::LTO2,
             0x44 => TapeDensity::LTO3,
@@ -164,23 +161,30 @@ impl TryFrom<u8> for TapeDensity {
     properties: {
         density: {
             type: TapeDensity,
+            optional: true,
         },
     },
 )]
 #[derive(Serialize,Deserialize)]
 #[serde(rename_all = "kebab-case")]
 /// Drive/Media status for Linux SCSI drives.
+///
+/// Media related data is optional - only set if there is a medium
+/// loaded.
 pub struct LinuxDriveAndMediaStatus {
     /// Block size (0 is variable size)
     pub blocksize: u32,
     /// Tape density
-    pub density: TapeDensity,
+    #[serde(skip_serializing_if="Option::is_none")]
+    pub density: Option<TapeDensity>,
     /// Status flags
     pub status: String,
     /// Current file number
-    pub file_number: i32,
+    #[serde(skip_serializing_if="Option::is_none")]
+    pub file_number: Option<u32>,
     /// Current block number
-    pub block_number: i32,
+    #[serde(skip_serializing_if="Option::is_none")]
+    pub block_number: Option<u32>,
     /// Medium Manufacture Date (epoch)
     #[serde(skip_serializing_if="Option::is_none")]
     pub manufactured: Option<i64>,

src/tape/drive/linux_tape.rs

@@ -41,10 +41,10 @@ use crate::{
 #[derive(Debug)]
 pub struct LinuxDriveStatus {
     pub blocksize: u32,
-    pub density: TapeDensity,
     pub status: GMTStatusFlags,
-    pub file_number: i32,
-    pub block_number: i32,
+    pub density: Option<TapeDensity>,
+    pub file_number: Option<u32>,
+    pub block_number: Option<u32>,
 }
 
 impl LinuxDriveStatus {
@@ -244,8 +244,6 @@ impl LinuxTapeHandle {
             bail!("MTIOCGET failed - {}", err);
         }
 
-        println!("{:?}", status);
-
         let gmt = GMTStatusFlags::from_bits_truncate(status.mt_gstat);
 
         let blocksize;
@@ -258,14 +256,24 @@ impl LinuxTapeHandle {
 
         let density = ((status.mt_dsreg & MT_ST_DENSITY_MASK) >> MT_ST_DENSITY_SHIFT) as u8;
 
-        let density = TapeDensity::try_from(density)?;
-
         Ok(LinuxDriveStatus {
             blocksize,
-            density,
             status: gmt,
-            file_number: status.mt_fileno,
-            block_number: status.mt_blkno,
+            density: if density != 0 {
+                Some(TapeDensity::try_from(density)?)
+            } else {
+                None
+            },
+            file_number: if status.mt_fileno > 0 {
+                Some(status.mt_fileno as u32)
+            } else {
+                None
+            },
+            block_number: if status.mt_blkno > 0 {
+                Some(status.mt_blkno as u32)
+            } else {
+                None
+            },
         })
     }