Move Identifier hashing into Self's Impl

src/glyph/builder.rs

@@ -1,6 +1,4 @@
-use std::collections::hash_map::DefaultHasher;
 use std::collections::HashSet;
-use std::hash::{Hash, Hasher};
 
 use crate::error::ErrorKind;
 use crate::glyph::{
@@ -144,7 +142,7 @@ impl GlyphBuilder {
             return Err(ErrorKind::UnexpectedTag);
         }
         if let Some(identifier) = &guideline.identifier {
-            let identifier_hash = Self::hash_identifier(&identifier);
+            let identifier_hash = identifier.hash();
             if !self.identifiers.insert(identifier_hash) {
                 return Err(ErrorKind::DuplicateIdentifier);
             }
@@ -161,7 +159,7 @@ impl GlyphBuilder {
             return Err(ErrorKind::UnexpectedTag);
         }
         if let Some(identifier) = &anchor.identifier {
-            let identifier_hash = Self::hash_identifier(&identifier);
+            let identifier_hash = identifier.hash();
             if !self.identifiers.insert(identifier_hash) {
                 return Err(ErrorKind::DuplicateIdentifier);
             }
@@ -242,7 +240,7 @@ impl GlyphBuilder {
             return Err(ErrorKind::UnexpectedAttribute);
         }
         if let Some(identifier) = &identifier {
-            let identifier_hash = Self::hash_identifier(&identifier);
+            let identifier_hash = identifier.hash();
             if !self.identifiers.insert(identifier_hash) {
                 return Err(ErrorKind::DuplicateIdentifier);
             }
@@ -304,7 +302,7 @@ impl GlyphBuilder {
                 }
                 if let Some(identifier) = &point.identifier {
                     // TODO: test membership at fn start and insert() before push()?
-                    let identifier_hash = Self::hash_identifier(&identifier);
+                    let identifier_hash = identifier.hash();
                     if !self.identifiers.insert(identifier_hash) {
                         return Err(ErrorKind::DuplicateIdentifier);
                     }
@@ -400,7 +398,7 @@ impl GlyphBuilder {
             return Err(ErrorKind::UnexpectedAttribute);
         }
         if let Some(identifier) = &identifier {
-            let identifier_hash = Self::hash_identifier(&identifier);
+            let identifier_hash = identifier.hash();
             if !self.identifiers.insert(identifier_hash) {
                 return Err(ErrorKind::DuplicateIdentifier);
             }
@@ -410,13 +408,6 @@ impl GlyphBuilder {
         Ok(self)
     }
 
-    /// Return the u64 hash value of an Identifier.
-    fn hash_identifier(identifier: &Identifier) -> u64 {
-        let mut hasher = DefaultHasher::new();
-        identifier.hash(&mut hasher);
-        hasher.finish()
-    }
-
     /// Check if a contour is really an informal anchor according to the Glif v2 specification.
     fn contour_is_v1_anchor(format: &GlifVersion, points: &[ContourPoint]) -> bool {
         *format == GlifVersion::V1
@@ -426,6 +417,17 @@ impl GlyphBuilder {
     }
 }
 
+// #[derive(Debug)]
+// pub struct OutlineBuilder {
+//     identifiers: HashSet<u64>, // All identifiers within a glyph must be unique.
+//     scratch_contour: Option<Contour>,
+//     number_of_offcurves: u32,
+// }
+
+// impl OutlineBuilder {
+
+// }
+
 #[cfg(test)]
 mod tests {
     use super::*;

src/shared_types.rs

@@ -1,4 +1,6 @@
+use std::collections::hash_map::DefaultHasher;
 use std::convert::TryFrom;
+use std::hash::{Hash, Hasher};
 use std::ops::Deref;
 use std::str::FromStr;
 
@@ -76,6 +78,13 @@ impl Identifier {
     pub fn as_str(&self) -> &str {
         &self.0
     }
+
+    /// Return the u64 hash value of self.
+    pub fn hash(&self) -> u64 {
+        let mut hasher = DefaultHasher::new();
+        Hash::hash(&self, &mut hasher);
+        hasher.finish()
+    }
 }
 
 impl FromStr for Identifier {