chore(sprout): implement iterator stamping to cleanup code

crates/boot/src/actions/chainload.rs

@@ -21,7 +21,7 @@ pub fn chainload(context: Rc<SproutContext>, configuration: &ChainloadConfigurat
     // Resolve the path to the image to chainload.
     let resolved = eficore::path::resolve_path(
         Some(context.root().loaded_image_path()?),
-        &context.stamp(&configuration.path),
+        context.stamp(&configuration.path),
     )
     .context("unable to resolve chainload path")?;
 
@@ -38,8 +38,7 @@ pub fn chainload(context: Rc<SproutContext>, configuration: &ChainloadConfigurat
             .context("unable to open loaded image protocol")?;
 
     // Stamp and combine the options to pass to the image.
-    let options =
-        utils::combine_options(configuration.options.iter().map(|item| context.stamp(item)));
+    let options = utils::combine_options(context.stamp_iter(configuration.options.iter()));
 
     // Pass the load options to the image.
     // If no options are provided, the resulting string will be empty.
@@ -50,6 +49,7 @@ pub fn chainload(context: Rc<SproutContext>, configuration: &ChainloadConfigurat
             .context("unable to convert chainloader options to CString16")?,
     );
 
+    // Ensure the chainloader options limit is not exceeded.
     if options.num_bytes() > u32::MAX as usize {
         bail!("chainloader options too large");
     }

crates/boot/src/actions/edera.rs

@@ -20,20 +20,11 @@ use uefi::Guid;
 /// Builds a configuration string for the Xen EFI stub using the specified `configuration`.
 fn build_xen_config(context: Rc<SproutContext>, configuration: &EderaConfiguration) -> String {
     // Stamp xen options and combine them.
-    let xen_options = utils::combine_options(
-        configuration
-            .xen_options
-            .iter()
-            .map(|item| context.stamp(item)),
-    );
+    let xen_options = utils::combine_options(context.stamp_iter(configuration.xen_options.iter()));
 
     // Stamp kernel options and combine them.
-    let kernel_options = utils::combine_options(
-        configuration
-            .kernel_options
-            .iter()
-            .map(|item| context.stamp(item)),
-    );
+    let kernel_options =
+        utils::combine_options(context.stamp_iter(configuration.kernel_options.iter()));
 
     // xen config file format is ini-like
     [

crates/boot/src/context.rs

@@ -269,6 +269,15 @@ impl SproutContext {
         Self::stamp_values(&self.all_values(), text.as_ref()).1
     }
 
+    /// Stamps all the items from the iterator `input` with all the values in this [SproutContext]
+    /// and it's parents. This calls [self.stamp] on each item.
+    pub fn stamp_iter(
+        &self,
+        input: impl Iterator<Item = impl AsRef<str>>,
+    ) -> impl Iterator<Item = String> {
+        input.map(|item| self.stamp(item))
+    }
+
     /// Unloads a [SproutContext] back into an owned context. This
     /// may not succeed if something else is holding onto the value.
     pub fn unload(self: Rc<SproutContext>) -> Option<SproutContext> {

crates/boot/src/drivers.rs

@@ -18,7 +18,7 @@ fn load_driver(context: Rc<SproutContext>, driver: &DriverDeclaration) -> Result
     // Resolve the path to the driver image.
     let resolved = eficore::path::resolve_path(
         Some(context.root().loaded_image_path()?),
-        &context.stamp(&driver.path),
+        context.stamp(&driver.path),
     )
     .context("unable to resolve path to driver")?;
 

crates/boot/src/generators/list.rs

@@ -22,11 +22,10 @@ pub fn generate(
 
         // Stamp the entry title and actions from the template.
         let mut entry = list.entry.clone();
-        entry.actions = entry
-            .actions
-            .into_iter()
-            .map(|action| context.stamp(action))
-            .collect();
+
+        // Stamp all the actions this entry references.
+        entry.actions = context.stamp_iter(entry.actions.into_iter()).collect();
+
         // Push the entry into the list with the new context.
         entries.push(BootableEntry::new(
             index.to_string(),