fixup! core: Add helpers for checking mechanisms at compile time

core/src/types.rs

@@ -457,16 +457,17 @@ macro_rules! generate_mechanism {
         $(#[$outer:meta])*
         $vis:vis enum $name:ident {
             $(
+                #[cfg($($cfg_cond:tt)*)]
                 $(#[$inner:meta])*
-                $feature:literal: $variant:ident,
+                $variant:ident,
             )*
         }
     ) => {
         $(#[$outer])*
         $vis enum $name {
             $(
+                #[cfg($($cfg_cond)*)]
                 $(#[$inner])*
-                #[cfg(feature = $feature)]
                 $variant,
             )*
         }
@@ -477,7 +478,7 @@ macro_rules! generate_mechanism {
             /// The contents of this constant depends on the enabled features.
             pub const ENABLED: &[Self] = &[
                 $(
-                    #[cfg(feature = $feature)]
+                    #[cfg($($cfg_cond)*)]
                     Self::$variant,
                 )*
             ];
@@ -487,7 +488,7 @@ macro_rules! generate_mechanism {
                 let _ = other;
                 match *self {
                     $(
-                        #[cfg(feature = $feature)]
+                        #[cfg($($cfg_cond)*)]
                         Self::$variant => matches!(other, Self::$variant),
                     )*
                 }
@@ -500,7 +501,7 @@ macro_rules! generate_mechanism {
             pub const fn panic(&self) -> ! {
                 match *self {
                     $(
-                        #[cfg(feature = $feature)]
+                        #[cfg($($cfg_cond)*)]
                         Self::$variant => panic!(concat!("panic for mechanism: ", stringify!($variant))),
                     )*
                 }
@@ -513,53 +514,86 @@ generate_mechanism! {
     #[derive(Copy, Clone, Eq, PartialEq, Debug, Serialize, Deserialize)]
     #[non_exhaustive]
     pub enum Mechanism {
-        "aes256-cbc": Aes256Cbc,
-        "chacha8-poly1305": Chacha8Poly1305,
-        "ed255": Ed255,
-        "hmac-blake2s": HmacBlake2s,
-        "hmac-sha1": HmacSha1,
-        "hmac-sha256": HmacSha256,
-        "hmac-sha512": HmacSha512,
+        #[cfg(feature = "aes256-cbc")]
+        Aes256Cbc,
+        #[cfg(feature = "chacha8-poly1305")]
+        Chacha8Poly1305,
+        #[cfg(feature = "ed255")]
+        Ed255,
+        #[cfg(feature = "hmac-blake2s")]
+        HmacBlake2s,
+        #[cfg(feature = "hmac-sha1")]
+        HmacSha1,
+        #[cfg(feature = "hmac-sha256")]
+        HmacSha256,
+        #[cfg(feature = "hmac-sha512")]
+        HmacSha512,
         // P256XSha256,
-        "p256": P256,
-        "p256": P256Prehashed,
-        "p384": P384,
-        "p384": P384Prehashed,
-        "p521": P521,
-        "p521": P521Prehashed,
-        "brainpoolp256r1": BrainpoolP256R1,
-        "brainpoolp256r1": BrainpoolP256R1Prehashed,
-        "brainpoolp384r1": BrainpoolP384R1,
-        "brainpoolp384r1": BrainpoolP384R1Prehashed,
-        "brainpoolp512r1": BrainpoolP512R1,
-        "brainpoolp512r1": BrainpoolP512R1Prehashed,
-        "secp256k1": Secp256k1,
-        "secp256k1": Secp256k1Prehashed,
+        #[cfg(feature = "p256")]
+        P256,
+        #[cfg(feature = "p256")]
+        P256Prehashed,
+        #[cfg(feature = "p384")]
+        P384,
+        #[cfg(feature = "p384")]
+        P384Prehashed,
+        #[cfg(feature = "p521")]
+        P521,
+        #[cfg(feature = "p521")]
+        P521Prehashed,
+        #[cfg(feature = "brainpoolp256r1")]
+        BrainpoolP256R1,
+        #[cfg(feature = "brainpoolp256r1")]
+        BrainpoolP256R1Prehashed,
+        #[cfg(feature = "brainpoolp384r1")]
+        BrainpoolP384R1,
+        #[cfg(feature = "brainpoolp384r1")]
+        BrainpoolP384R1Prehashed,
+        #[cfg(feature = "brainpoolp512r1")]
+        BrainpoolP512R1,
+        #[cfg(feature = "brainpoolp512r1")]
+        BrainpoolP512R1Prehashed,
+        #[cfg(feature = "secp256k1")]
+        Secp256k1,
+        #[cfg(feature = "secp256k1")]
+        Secp256k1Prehashed,
         // clients can also do hashing by themselves
-        "sha256": Sha256,
-        "tdes": Tdes,
-        "totp": Totp,
-        "trng": Trng,
-        "x255": X255,
+        #[cfg(feature = "sha256")]
+        Sha256,
+        #[cfg(feature = "tdes")]
+        Tdes,
+        #[cfg(feature = "totp")]
+        Totp,
+        #[cfg(feature = "trng")]
+        Trng,
+        #[cfg(feature = "x255")]
+        X255,
+        #[cfg(feature = "shared-secret")]
         /// Used to serialize the output of a diffie-hellman
-        "shared-secret": SharedSecret,
+        SharedSecret,
 
+        #[cfg(feature = "rsa2048")]
         /// Exposes the Raw RSA encryption/decryption primitive. Be aware this is dangerous.
         /// Not having any padding can allow an attacker to obtain plaintexts and forge signatures.
         /// It should only be used if absolutely necessary.
-        "rsa2048": Rsa2048Raw,
+        Rsa2048Raw,
+        #[cfg(feature = "rsa3072")]
         /// Exposes the Raw RSA encryption/decryption primitive. Be aware this is dangerous.
         /// Not having any padding can allow an attacker to obtain plaintexts and forge signatures.
         /// It should only be used if absolutely necessary.
-        "rsa3072": Rsa3072Raw,
+        Rsa3072Raw,
+        #[cfg(feature = "rsa4096")]
         /// Exposes the Raw RSA encryption/decryption primitive. Be aware this is dangerous.
         /// Not having any padding can allow an attacker to obtain plaintexts and forge signatures.
         /// It should only be used if absolutely necessary.
-        "rsa4096": Rsa4096Raw,
-
-        "rsa2048": Rsa2048Pkcs1v15,
-        "rsa3072": Rsa3072Pkcs1v15,
-        "rsa4096": Rsa4096Pkcs1v15,
+        Rsa4096Raw,
+
+        #[cfg(feature = "rsa2048")]
+        Rsa2048Pkcs1v15,
+        #[cfg(feature = "rsa3072")]
+        Rsa3072Pkcs1v15,
+        #[cfg(feature = "rsa4096")]
+        Rsa4096Pkcs1v15,
     }
 }