Extract DescriptorInnerKey trait

src/descriptor/key.rs

@@ -531,15 +531,9 @@ impl error::Error for ConversionError {
     }
 }
 
-impl DescriptorExtendedPublicKey {
+pub trait DescriptorInnerKey {
     /// The fingerprint of the master key associated with this key, `0x00000000` if none.
-    pub fn master_fingerprint(&self) -> bip32::Fingerprint {
-        if let Some((fingerprint, _)) = self.origin {
-            fingerprint
-        } else {
-            self.xkey.fingerprint()
-        }
-    }
+    fn master_fingerprint(&self) -> bip32::Fingerprint;
 
     /// Full path, from the master key
     ///
@@ -548,19 +542,10 @@ impl DescriptorExtendedPublicKey {
     /// to the wildcard type (hardened or normal).
     ///
     /// For multipath extended keys, this returns `None`.
-    pub fn full_derivation_path(&self) -> Option<bip32::DerivationPath> {
-        let origin_path = if let Some((_, ref path)) = self.origin {
-            path.clone()
-        } else {
-            bip32::DerivationPath::from(vec![])
-        };
-        Some(origin_path.extend(&self.derivation_path))
-    }
+    fn full_derivation_path(&self) -> Option<bip32::DerivationPath>;
 
     /// Whether or not the key has a wildcard
-    pub fn has_wildcard(&self) -> bool {
-        self.wildcard != Wildcard::None
-    }
+    fn has_wildcard(&self) -> bool;
 
     /// Replaces any wildcard (i.e. `/*`) in the key with a particular derivation index, turning it into a
     /// *definite* key (i.e. one where all the derivation paths are set).
@@ -574,7 +559,35 @@ impl DescriptorExtendedPublicKey {
     /// # Errors
     ///
     /// - If `index` is hardened.
-    pub fn at_derivation_index(self, index: u32) -> Result<DefiniteDescriptorKey, ConversionError> {
+    fn at_derivation_index(self, index: u32) -> Result<DefiniteDescriptorKey, ConversionError>;
+
+    /// Whether or not this key has multiple derivation paths.
+    fn is_multipath(&self) -> bool;
+}
+
+impl DescriptorInnerKey for DescriptorExtendedPublicKey {
+    fn master_fingerprint(&self) -> bip32::Fingerprint {
+        if let Some((fingerprint, _)) = self.origin {
+            fingerprint
+        } else {
+            self.xkey.fingerprint()
+        }
+    }
+
+    fn full_derivation_path(&self) -> Option<bip32::DerivationPath> {
+        let origin_path = if let Some((_, ref path)) = self.origin {
+            path.clone()
+        } else {
+            bip32::DerivationPath::from(vec![])
+        };
+        Some(origin_path.extend(&self.derivation_path))
+    }
+
+    fn has_wildcard(&self) -> bool {
+        self.wildcard != Wildcard::None
+    }
+
+    fn at_derivation_index(self, index: u32) -> Result<DefiniteDescriptorKey, ConversionError> {
         let derivation_path = match self.wildcard {
             Wildcard::None => self.derivation_path,
             Wildcard::Unhardened => self.derivation_path.into_child(
@@ -599,8 +612,7 @@ impl DescriptorExtendedPublicKey {
             .expect("The key should not contain any wildcards at this point"))
     }
 
-    /// Whether or not this key has multiple derivation paths.
-    pub fn is_multipath(&self) -> bool {
+    fn is_multipath(&self) -> bool {
         false
     }
 }