Addr ref helper

packages/std/src/addresses.rs

@@ -4,8 +4,10 @@ use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
 use std::fmt;
 use std::ops::Deref;
+use std::str::from_utf8;
 
 use crate::binary::Binary;
+use crate::errors::StdResult;
 
 /// A human readable address.
 ///
@@ -45,6 +47,17 @@ impl Addr {
     pub fn unchecked<T: Into<String>>(input: T) -> Addr {
         Addr(input.into())
     }
+
+    #[inline]
+    pub fn as_str(&self) -> &str {
+        self.0.as_str()
+    }
+
+    /// This gets an AddrRef, much like OwnedDeps.as_ref
+    /// We don't implement AsRef as we want an object back, not &AddrRef
+    pub fn as_ref(&'_ self) -> AddrRef<'_> {
+        AddrRef(self.as_str())
+    }
 }
 
 impl fmt::Display for Addr {
@@ -53,13 +66,6 @@ impl fmt::Display for Addr {
     }
 }
 
-impl AsRef<str> for Addr {
-    #[inline]
-    fn as_ref(&self) -> &str {
-        &self.0
-    }
-}
-
 /// Implement `Addr == &str`
 impl PartialEq<&str> for Addr {
     fn eq(&self, rhs: &&str) -> bool {
@@ -74,6 +80,12 @@ impl PartialEq<Addr> for &str {
     }
 }
 
+impl<'a> PartialEq<AddrRef<'a>> for Addr {
+    fn eq(&self, rhs: &AddrRef<'a>) -> bool {
+        self.0.as_str() == rhs.as_str()
+    }
+}
+
 /// Implement `Addr == String`
 impl PartialEq<String> for Addr {
     fn eq(&self, rhs: &String) -> bool {
@@ -103,15 +115,47 @@ impl From<&Addr> for String {
     }
 }
 
-impl From<Addr> for HumanAddr {
-    fn from(addr: Addr) -> Self {
-        HumanAddr(addr.0)
+/// AddrRef is like &Addr but can be created easily without requiring a heap allocation
+/// It is not designed to be serialized but used internally, especially working with storage-plus keys
+#[derive(Debug, Clone, Copy)]
+pub struct AddrRef<'a>(&'a str);
+
+impl<'a> AddrRef<'a> {
+    /// the safe way to construct one from an address (also via From/Into helpers)
+    pub fn new(addr: &'a Addr) -> Self {
+        AddrRef(addr.as_str())
+    }
+
+    /// This should only be used in test code
+    pub const fn unchecked(addr: &'a str) -> Self {
+        AddrRef(addr)
+    }
+
+    /// This is for parsing raw keys stored in the db we created previously with Addr
+    pub fn unchecked_utf8(raw: &'a [u8]) -> StdResult<Self> {
+        Ok(AddrRef(from_utf8(raw)?))
+    }
+
+    pub fn as_str(&self) -> &str {
+        self.0
     }
 }
 
-impl From<&Addr> for HumanAddr {
-    fn from(addr: &Addr) -> Self {
-        HumanAddr(addr.0.clone())
+impl<'a> From<&'a Addr> for AddrRef<'a> {
+    fn from(addr: &'a Addr) -> Self {
+        AddrRef(addr.as_str())
+    }
+}
+
+impl<'a> PartialEq<&str> for AddrRef<'a> {
+    fn eq(&self, rhs: &&str) -> bool {
+        self.0 == *rhs
+    }
+}
+
+impl<'a> From<AddrRef<'a>> for Addr {
+    fn from(addr: AddrRef<'a>) -> Self {
+        Addr(addr.0.to_string())
     }
 }
 
@@ -265,6 +309,11 @@ mod tests {
     use std::hash::{Hash, Hasher};
     use std::iter::FromIterator;
 
+    // Let's see if we can get this directly from Addr
+    fn demo_deref(addr: AddrRef, compare: &str) {
+        assert_eq!(addr, compare);
+    }
+
     #[test]
     fn addr_unchecked_works() {
         let a = Addr::unchecked("123");
@@ -288,6 +337,12 @@ mod tests {
         assert_eq!(addr.as_ref(), "literal-string");
     }
 
+    #[test]
+    fn addr_as_str() {
+        let addr = Addr::unchecked("literal-string");
+        assert_eq!(addr.as_str(), "literal-string");
+    }
+
     #[test]
     fn addr_implements_partial_eq_with_str() {
         let addr = Addr::unchecked("cos934gh9034hg04g0h134");
@@ -323,17 +378,35 @@ mod tests {
     }
 
     #[test]
-    fn addr_implements_into_human_address() {
-        // owned Addr
-        let addr = Addr::unchecked("cos934gh9034hg04g0h134");
-        let human: HumanAddr = addr.into();
-        assert_eq!(human, "cos934gh9034hg04g0h134");
+    fn addr_ref_unchecked_from_literal() {
+        let addr_ref = AddrRef::unchecked("my-address");
+        assert_eq!(addr_ref.as_str(), "my-address");
+        // PartialEq also implemented
+        assert_eq!(addr_ref, "my-address");
+    }
 
-        // &Addr
-        let addr = Addr::unchecked("cos934gh9034hg04g0h134");
-        let addr_ref = &addr;
-        let human: HumanAddr = addr_ref.into();
-        assert_eq!(human, "cos934gh9034hg04g0h134");
+    #[test]
+    fn addr_ref_unchecked_from_bytes() {
+        let addr_ref = AddrRef::unchecked_utf8(b"some-text").unwrap();
+        assert_eq!(addr_ref.as_str(), "some-text");
+        // returns an error if we pass bad data in ("Invalid 2 octet sequence")
+        AddrRef::unchecked_utf8(&[0xc3, 0x28]).unwrap_err();
+    }
+
+    #[test]
+    fn addr_ref_to_addr() {
+        let addr_ref = AddrRef::unchecked("foobar");
+        let addr: Addr = addr_ref.into();
+        // same strings
+        assert_eq!(addr.as_str(), addr_ref.as_str());
+        // helper also works
+        assert_eq!(addr, addr_ref);
+    }
+
+    #[test]
+    fn addr_to_addr_ref() {
+        let addr = Addr::unchecked("some-long-string");
+        demo_deref(addr.as_ref(), "some-long-string");
     }
 
     // Test HumanAddr as_str() for each HumanAddr::from input type