Flatten API (#274)

Re-exports types from the toplevel instead of placing them in individual
modules (often which only contain one type).

This makes the API easier for users to navigate, while still retaining
the same module structure internally.

Additionally, this commit uses the `uuid` crate for modeling UUIDs.

src/cccid.rs

@@ -32,15 +32,12 @@
 
 use crate::{Error, Result, YubiKey};
 use getrandom::getrandom;
-use std::fmt::{self, Debug, Display};
+use std::{
+    fmt::{self, Debug, Display},
+    str,
+};
 use subtle_encoding::hex;
 
-/// CCCID size
-pub const CCCID_SIZE: usize = 14;
-
-/// CCC size
-pub const CCC_SIZE: usize = 51;
-
 /// CCCID offset
 const CCC_ID_OFFS: usize = 9;
 
@@ -62,28 +59,34 @@ const CCC_TMPL: &[u8] = &[
     0x00, 0xfe, 0x00,
 ];
 
-/// Cardholder Capability Container (CCC) Identifier Card ID
-#[derive(Copy, Clone, Debug, Eq, PartialEq)]
-pub struct CardId(pub [u8; CCCID_SIZE]);
+/// Cardholder Capability Container (CCC) Identifier Card ID.
+#[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
+pub struct CardId(pub [u8; Self::BYTE_SIZE]);
 
 impl CardId {
+    /// CCCID size in bytes
+    pub const BYTE_SIZE: usize = 14;
+
     /// Generate a random CCC Card ID
     pub fn generate() -> Result<Self> {
-        let mut id = [0u8; CCCID_SIZE];
+        let mut id = [0u8; Self::BYTE_SIZE];
         getrandom(&mut id).map_err(|_| Error::RandomnessError)?;
         Ok(Self(id))
     }
 }
 
-/// Cardholder Capability Container (CCC) Identifier
-#[derive(Copy, Clone)]
-pub struct Ccc(pub [u8; CCC_SIZE]);
+/// Cardholder Capability Container (CCC) Identifier.
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+pub struct Ccc(pub [u8; Self::BYTE_SIZE]);
 
 impl Ccc {
+    /// CCC size in bytes
+    pub const BYTE_SIZE: usize = 51;
+
     /// Return CardId component of CCC
     pub fn card_id(&self) -> Result<CardId> {
-        let mut cccid = [0u8; CCCID_SIZE];
-        cccid.copy_from_slice(&self.0[CCC_ID_OFFS..(CCC_ID_OFFS + CCCID_SIZE)]);
+        let mut cccid = [0u8; CardId::BYTE_SIZE];
+        cccid.copy_from_slice(&self.0[CCC_ID_OFFS..(CCC_ID_OFFS + CardId::BYTE_SIZE)]);
         Ok(CardId(cccid))
     }
 
@@ -96,8 +99,8 @@ impl Ccc {
             return Err(Error::GenericError);
         }
 
-        let mut ccc = [0u8; CCC_SIZE];
-        ccc.copy_from_slice(&response[0..CCC_SIZE]);
+        let mut ccc = [0u8; Self::BYTE_SIZE];
+        ccc.copy_from_slice(&response[0..Self::BYTE_SIZE]);
         Ok(Self(ccc))
     }
 
@@ -112,18 +115,8 @@ impl Ccc {
     }
 }
 
-impl Debug for Ccc {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "CCC({:?})", &self.0[..])
-    }
-}
-
 impl Display for Ccc {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(
-            f,
-            "{}",
-            String::from_utf8(hex::encode(&self.0[..])).unwrap()
-        )
+        write!(f, "{}", str::from_utf8(&hex::encode(&self.0[..])).unwrap())
     }
 }