Make comparison functions stable

secp256k1-sys/src/lib.rs

@@ -133,6 +133,7 @@ impl SchnorrSigExtraParams {
 
 /// Library-internal representation of a Secp256k1 public key
 #[repr(C)]
+#[derive(Copy, Clone)]
 pub struct PublicKey([c_uchar; 64]);
 impl_array_newtype!(PublicKey, c_uchar, 64);
 impl_raw_debug!(PublicKey);
@@ -169,10 +170,64 @@ impl PublicKey {
     pub fn underlying_bytes(self) -> [c_uchar; 64] {
         self.0
     }
+
+    /// Serializes this public key as a byte-encoded pair of values, in compressed form.
+    fn serialize(&self) -> [u8; 33] {
+        let mut buf = [0u8; 33];
+        let mut len = 33;
+        unsafe {
+            let ret = secp256k1_ec_pubkey_serialize(
+                secp256k1_context_no_precomp,
+                buf.as_mut_c_ptr(),
+                &mut len,
+                self,
+                SECP256K1_SER_COMPRESSED,
+            );
+            debug_assert_eq!(ret, 1);
+            debug_assert_eq!(len, 33);
+        };
+        buf
+    }
+}
+
+#[cfg(not(fuzzing))]
+impl PartialOrd for PublicKey {
+    fn partial_cmp(&self, other: &PublicKey) -> Option<core::cmp::Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+#[cfg(not(fuzzing))]
+impl Ord for PublicKey {
+    fn cmp(&self, other: &PublicKey) -> core::cmp::Ordering {
+        let ret = unsafe {
+            secp256k1_ec_pubkey_cmp(secp256k1_context_no_precomp, self, other)
+        };
+        ret.cmp(&0i32)
+    }
+}
+
+#[cfg(not(fuzzing))]
+impl PartialEq for PublicKey {
+    fn eq(&self, other: &Self) -> bool {
+        self.cmp(other) == core::cmp::Ordering::Equal
+    }
+}
+
+#[cfg(not(fuzzing))]
+impl Eq for PublicKey {}
+
+#[cfg(not(fuzzing))]
+impl core::hash::Hash for PublicKey {
+    fn hash<H: core::hash::Hasher>(&self, state: &mut H) {
+        let ser = self.serialize();
+        ser.hash(state);
+    }
 }
 
 /// Library-internal representation of a Secp256k1 signature
 #[repr(C)]
+#[derive(Copy, Clone)]
 pub struct Signature([c_uchar; 64]);
 impl_array_newtype!(Signature, c_uchar, 64);
 impl_raw_debug!(Signature);
@@ -209,9 +264,58 @@ impl Signature {
     pub fn underlying_bytes(self) -> [c_uchar; 64] {
         self.0
     }
+
+    /// Serializes the signature in compact format.
+    fn serialize(&self) -> [u8; 64] {
+        let mut buf = [0u8; 64];
+        unsafe {
+            let ret = secp256k1_ecdsa_signature_serialize_compact(
+                secp256k1_context_no_precomp,
+                buf.as_mut_c_ptr(),
+                self,
+            );
+            debug_assert!(ret == 1);
+        }
+        buf
+    }
+}
+
+#[cfg(not(fuzzing))]
+impl PartialOrd for Signature {
+    fn partial_cmp(&self, other: &Signature) -> Option<core::cmp::Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+#[cfg(not(fuzzing))]
+impl Ord for Signature {
+    fn cmp(&self, other: &Signature) -> core::cmp::Ordering {
+        let this = self.serialize();
+        let that = other.serialize();
+        this.cmp(&that)
+    }
+}
+
+#[cfg(not(fuzzing))]
+impl PartialEq for Signature {
+    fn eq(&self, other: &Self) -> bool {
+        self.cmp(other) == core::cmp::Ordering::Equal
+    }
+}
+
+#[cfg(not(fuzzing))]
+impl Eq for Signature {}
+
+#[cfg(not(fuzzing))]
+impl core::hash::Hash for Signature {
+    fn hash<H: core::hash::Hasher>(&self, state: &mut H) {
+        let ser = self.serialize();
+        ser.hash(state);
+    }
 }
 
 #[repr(C)]
+#[derive(Copy, Clone)]
 pub struct XOnlyPublicKey([c_uchar; 64]);
 impl_array_newtype!(XOnlyPublicKey, c_uchar, 64);
 impl_raw_debug!(XOnlyPublicKey);
@@ -248,9 +352,59 @@ impl XOnlyPublicKey {
     pub fn underlying_bytes(self) -> [c_uchar; 64] {
         self.0
     }
+
+    /// Serializes this key as a byte-encoded x coordinate value (32 bytes).
+    fn serialize(&self) -> [u8; 32] {
+        let mut buf = [0u8; 32];
+        unsafe {
+            let ret = secp256k1_xonly_pubkey_serialize(
+                secp256k1_context_no_precomp,
+                buf.as_mut_c_ptr(),
+                self,
+            );
+            assert_eq!(ret, 1);
+        };
+        buf
+    }
+}
+
+#[cfg(not(fuzzing))]
+impl PartialOrd for XOnlyPublicKey {
+    fn partial_cmp(&self, other: &XOnlyPublicKey) -> Option<core::cmp::Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+#[cfg(not(fuzzing))]
+impl Ord for XOnlyPublicKey {
+    fn cmp(&self, other: &XOnlyPublicKey) -> core::cmp::Ordering {
+        let ret = unsafe {
+            secp256k1_xonly_pubkey_cmp(secp256k1_context_no_precomp, self, other)
+        };
+        ret.cmp(&0i32)
+    }
+}
+
+#[cfg(not(fuzzing))]
+impl PartialEq for XOnlyPublicKey {
+    fn eq(&self, other: &Self) -> bool {
+        self.cmp(other) == core::cmp::Ordering::Equal
+    }
+}
+
+#[cfg(not(fuzzing))]
+impl Eq for XOnlyPublicKey {}
+
+#[cfg(not(fuzzing))]
+impl core::hash::Hash for XOnlyPublicKey {
+    fn hash<H: core::hash::Hasher>(&self, state: &mut H) {
+        let ser = self.serialize();
+        ser.hash(state);
+    }
 }
 
 #[repr(C)]
+#[derive(Copy, Clone)]
 pub struct KeyPair([c_uchar; 96]);
 impl_array_newtype!(KeyPair, c_uchar, 96);
 impl_raw_debug!(KeyPair);
@@ -287,6 +441,58 @@ impl KeyPair {
     pub fn underlying_bytes(self) -> [c_uchar; 96] {
         self.0
     }
+
+    /// Creates a new compressed public key from this key pair.
+    fn public_key(&self) -> PublicKey {
+        unsafe {
+            let mut pk = PublicKey::new();
+            let ret = secp256k1_keypair_pub(
+                secp256k1_context_no_precomp,
+                &mut pk,
+                self,
+            );
+            debug_assert_eq!(ret, 1);
+            pk
+        }
+    }
+}
+
+#[cfg(not(fuzzing))]
+impl PartialOrd for KeyPair {
+    fn partial_cmp(&self, other: &KeyPair) -> Option<core::cmp::Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+#[cfg(not(fuzzing))]
+impl Ord for KeyPair {
+    fn cmp(&self, other: &KeyPair) -> core::cmp::Ordering {
+        let this = self.public_key();
+        let that = other.public_key();
+        this.cmp(&that)
+    }
+}
+
+#[cfg(not(fuzzing))]
+impl PartialEq for KeyPair {
+    fn eq(&self, other: &Self) -> bool {
+        self.cmp(other) == core::cmp::Ordering::Equal
+    }
+}
+
+#[cfg(not(fuzzing))]
+impl Eq for KeyPair {}
+
+#[cfg(not(fuzzing))]
+impl core::hash::Hash for KeyPair {
+    fn hash<H: core::hash::Hasher>(&self, state: &mut H) {
+        // To hash the key pair we just hash the serialized public key. Since any change to the
+        // secret key would also be a change to the public key this is a valid one way function from
+        // the key pair to the digest.
+        let pk = self.public_key();
+        let ser = pk.serialize();
+        ser.hash(state);
+    }
 }
 
 extern "C" {

secp256k1-sys/src/macros.rs

@@ -17,75 +17,76 @@
 #[macro_export]
 macro_rules! impl_array_newtype {
     ($thing:ident, $ty:ty, $len:expr) => {
-        impl Copy for $thing {}
-
         impl $thing {
-            /// Converts the object to a raw pointer for FFI interfacing.
-            #[inline]
-            pub fn as_ptr(&self) -> *const $ty {
-                let &$thing(ref dat) = self;
-                dat.as_ptr()
+            /// Like `cmp::Ord` but faster and with no guarantees across library versions.
+            ///
+            /// The inner byte array of `Self` is passed across the FFI boundry, as such there are
+            /// no guarantees on its layout and it is subject to change across library versions,
+            /// even minor versions. For this reason comparison function implementations (e.g.
+            /// `Ord`, `PartialEq`) take measures to ensure the data will remain constant (e.g., by
+            /// serializing it to a guaranteed format). This means they may be slow, this function
+            /// provides a faster comparison if you know that your types come from the same library
+            /// version.
+            pub fn cmp_fast_unstable(&self, other: &Self) -> core::cmp::Ordering {
+                self[..].cmp(&other[..])
             }
 
-            /// Converts the object to a mutable raw pointer for FFI interfacing.
-            #[inline]
-            pub fn as_mut_ptr(&mut self) -> *mut $ty {
-                let &mut $thing(ref mut dat) = self;
-                dat.as_mut_ptr()
+            /// Like `cmp::Eq` but faster and with no guarantees across library versions.
+            ///
+            /// The inner byte array of `Self` is passed across the FFI boundry, as such there are
+            /// no guarantees on its layout and it is subject to change across library versions,
+            /// even minor versions. For this reason comparison function implementations (e.g.
+            /// `Ord`, `PartialEq`) take measures to ensure the data will remain constant (e.g., by
+            /// serializing it to a guaranteed format). This means they may be slow, this function
+            /// provides a faster equality check if you know that your types come from the same
+            /// library version.
+            pub fn eq_fast_unstable(&self, other: &Self) -> bool {
+                self[..].eq(&other[..])
             }
-
-            /// Returns the length of the object as an array.
-            #[inline]
-            pub fn len(&self) -> usize { $len }
-
-            /// Returns whether the object as an array is empty.
-            #[inline]
-            pub fn is_empty(&self) -> bool { false }
         }
 
-        impl AsRef<[$ty; $len]> for $thing {
-            #[inline]
-            /// Gets a reference to the underlying array
-            fn as_ref(&self) -> &[$ty; $len] {
-                let &$thing(ref dat) = self;
-                dat
-            }
-        }
+        // We cannot derive these traits because Rust 1.41.1 requires `std::array::LengthAtMost32`.
 
+       #[cfg(fuzzing)]
         impl PartialEq for $thing {
             #[inline]
             fn eq(&self, other: &$thing) -> bool {
                 &self[..] == &other[..]
             }
         }
 
+        #[cfg(fuzzing)]
         impl Eq for $thing {}
 
-        impl ::core::hash::Hash for $thing {
-            fn hash<H: ::core::hash::Hasher>(&self, state: &mut H) {
+        #[cfg(fuzzing)]
+        impl core::hash::Hash for $thing {
+            fn hash<H: core::hash::Hasher>(&self, state: &mut H) {
                 (&self[..]).hash(state)
             }
         }
 
+        #[cfg(fuzzing)]
         impl PartialOrd for $thing {
             #[inline]
             fn partial_cmp(&self, other: &$thing) -> Option<core::cmp::Ordering> {
                 self[..].partial_cmp(&other[..])
             }
         }
 
+        #[cfg(fuzzing)]
         impl Ord for $thing {
             #[inline]
             fn cmp(&self, other: &$thing) -> core::cmp::Ordering {
                 self[..].cmp(&other[..])
             }
         }
 
-        impl Clone for $thing {
+        impl AsRef<[$ty; $len]> for $thing {
             #[inline]
-            fn clone(&self) -> $thing {
+            /// Gets a reference to the underlying array
+            fn as_ref(&self) -> &[$ty; $len] {
                 let &$thing(ref dat) = self;
-                $thing(dat.clone())
+                dat
             }
         }
 
@@ -101,20 +102,15 @@ macro_rules! impl_array_newtype {
 
         impl $crate::CPtr for $thing {
             type Target = $ty;
+
             fn as_c_ptr(&self) -> *const Self::Target {
-                if self.is_empty() {
-                    core::ptr::null()
-                } else {
-                    self.as_ptr()
-                }
+                let &$thing(ref dat) = self;
+                dat.as_ptr()
             }
 
             fn as_mut_c_ptr(&mut self) -> *mut Self::Target {
-                if self.is_empty() {
-                    core::ptr::null::<Self::Target>() as *mut _
-                } else {
-                    self.as_mut_ptr()
-                }
+                let &mut $thing(ref mut dat) = self;
+                dat.as_mut_ptr()
             }
         }
     }