feat(boot): introduce sort keys, which are sorted in reverse order, to make boot order more configurable (#55)

crates/boot/src/autoconfigure/linux.rs

@@ -1,5 +1,4 @@
 use crate::utils;
-use crate::utils::vercmp;
 use alloc::collections::BTreeMap;
 use alloc::string::{String, ToString};
 use alloc::vec::Vec;
@@ -186,17 +185,15 @@ pub fn scan(
         return Ok(false);
     }
 
-    // Sort the kernel pairs by kernel version, if it has one, newer kernels first.
-    pairs.sort_by(|a, b| vercmp::compare_versions(&a.kernel, &b.kernel).reverse());
-
     // Generate a unique name for the linux chainload action.
-    let chainload_action_name = format!("{}{}", LINUX_CHAINLOAD_ACTION_PREFIX, root_unique_hash,);
+    let chainload_action_name = format!("{}{}", LINUX_CHAINLOAD_ACTION_PREFIX, root_unique_hash);
 
     // Kernel pairs are detected, generate a list configuration for it.
     let generator = ListConfiguration {
         entry: EntryDeclaration {
             title: "Boot Linux $name".to_string(),
             actions: vec![chainload_action_name.clone()],
+            sort_key: Some("$kernel".to_string()),
             ..Default::default()
         },
         values: pairs

crates/boot/src/autoconfigure/windows.rs

@@ -51,13 +51,14 @@ pub fn scan(
     let chainload_action_name = format!("{}{}", WINDOWS_CHAINLOAD_ACTION_PREFIX, root_unique_hash,);
 
     // Generate an entry name for Windows.
-    let entry_name = format!("auto-windows-{}", root_unique_hash,);
+    let entry_name = format!("auto-windows-{}", root_unique_hash);
 
     // Create an entry for Windows and insert it into the configuration.
     let entry = EntryDeclaration {
         title: "Boot Windows".to_string(),
         actions: vec![chainload_action_name.clone()],
         values: Default::default(),
+        sort_key: None, // Use the default sort key.
     };
     config.entries.insert(entry_name, entry);
 

crates/boot/src/entries.rs

@@ -12,6 +12,7 @@ pub struct BootableEntry {
     declaration: EntryDeclaration,
     default: bool,
     pin_name: bool,
+    sort_key: Option<String>,
 }
 
 impl BootableEntry {
@@ -29,6 +30,7 @@ impl BootableEntry {
             declaration,
             default: false,
             pin_name: false,
+            sort_key: None,
         }
     }
 
@@ -107,6 +109,22 @@ impl BootableEntry {
         self.name == needle || self.title == needle
     }
 
+    /// Set the sort key of the entry. This is used to sort entries via version comparison.
+    pub fn set_sort_key(&mut self, sort_key: String) {
+        self.sort_key = Some(sort_key);
+    }
+
+    /// Retrieve a reference to the sort key of the entry. If one is not specified, we will use the
+    /// name of the entry.
+    pub fn sort_key(&self) -> &str {
+        // Use the sort key specified in the bootable entry, or use the declaration sort key,
+        // or use the name of the entry.
+        self.sort_key
+            .as_deref()
+            .or(self.declaration.sort_key.as_deref())
+            .unwrap_or(&self.name)
+    }
+
     /// Find an entry by `needle` inside the entry iterator `haystack`.
     /// This will search for an entry by name, title, or index.
     pub fn find<'a>(

crates/boot/src/generators/bls.rs

@@ -206,6 +206,16 @@ pub fn generate(context: Rc<SproutContext>, bls: &BlsConfiguration) -> Result<Ve
     // Sort all the entries according to the BLS sort system.
     entries.sort_by(sort_entries);
 
+    // Grab the number of entries that we have, so we can calculate a reverse index.
+    let entry_count = entries.len();
+
+    // Set the sort keys of all the bootable entries to a semi-unique prefix + the BLS sort order.
+    // The final comparison happens using version comparison, so this will sort
+    // things properly.
+    for (idx, (_bls, boot)) in entries.iter_mut().enumerate() {
+        boot.set_sort_key(format!("bls-{}-{}", path, entry_count - idx - 1));
+    }
+
     // Collect all the bootable entries and return them.
     Ok(entries.into_iter().map(|(_, boot)| boot).collect())
 }

crates/boot/src/main.rs

@@ -7,6 +7,7 @@ use crate::context::{RootContext, SproutContext};
 use crate::entries::BootableEntry;
 use crate::options::SproutOptions;
 use crate::phases::phase;
+use crate::utils::vercmp::compare_versions;
 use alloc::collections::BTreeMap;
 use alloc::format;
 use alloc::string::ToString;
@@ -257,6 +258,10 @@ fn run() -> Result<()> {
         }
     }
 
+    // Sort the entries by their sort key, finalizing the order to show entries. This happens
+    // in reverse order so that entries that would come last show up first in the menu.
+    entries.sort_by(|a, b| compare_versions(a.sort_key(), b.sort_key()).reverse());
+
     // Tell the bootloader interface what entries are available.
     BootloaderInterface::set_entries(entries.iter().map(|entry| entry.name()))
         .context("unable to set entries in bootloader interface")?;

crates/config/src/entries.rs

@@ -18,4 +18,7 @@ pub struct EntryDeclaration {
     /// The values to insert into the context when the entry is selected.
     #[serde(default)]
     pub values: BTreeMap<String, String>,
+    /// The key to sort entries, via version comparison.
+    #[serde(default, rename = "sort-key")]
+    pub sort_key: Option<String>,
 }