Segregate device specific generation to its own struct

Author: tones111

src/lib.rs

@@ -439,12 +439,21 @@ mod generate;
 mod util;
 
 pub use util::Target;
-use util::build_rs;
 
 pub struct Generation {
     pub lib_rs: String,
+    pub device_specific: Option<DeviceSpecific>,
+
+    // Reserve the right to add more fields to this struct
+    _extensible: (),
+}
+
+pub struct DeviceSpecific {
     pub device_x: String,
     pub build_rs: String,
+
+    // Reserve the right to add more fields to this struct
+    _extensible: (),
 }
 
 type Result<T> = std::result::Result<T, SvdError>;
@@ -470,11 +479,23 @@ pub fn generate(xml: &str, target: &Target, nightly: bool) -> Result<Generation>
         quote! {
             #(#items)*
         }
-    ).or(Err(SvdError::Fmt))?;
+    )
+    .or(Err(SvdError::Fmt))?;
+
+    let device_specific = if device_x.is_empty() {
+        None
+    } else {
+        Some(DeviceSpecific {
+            device_x: device_x,
+            build_rs: util::build_rs().to_string(),
+            _extensible: (),
+        })
+    };
+
     Ok(Generation {
         lib_rs: lib_rs,
-        device_x: device_x,
-        build_rs: build_rs().to_string(),
+        device_specific: device_specific,
+        _extensible: (),
     })
 }