use macros to impl literacy traits

Author: sgeisler

examples/write.rs

@@ -0,0 +1,15 @@
+extern crate bitcoin_hashes;
+
+use bitcoin_hashes::literacy::Write;
+use bitcoin_hashes::{sha256d, Hash, hash_newtype, hex_fmt_impl, index_impl, serde_impl, borrow_slice_impl};
+
+hash_newtype!(Txid, sha256d::Hash, 32, doc="A bitcoin transaction hash/transaction ID.");
+
+fn do_it<W: Write>(mut w: W) {
+    let _ = w.write_all(&[0u8; 1]);
+}
+
+fn main() {
+    let mut enc = Txid::engine();
+    do_it(&mut enc);
+}

src/impls.rs

@@ -19,97 +19,59 @@
 use {sha1, sha256, sha512, ripemd160, siphash24};
 use ::{HashEngine, literacy};
 
-#[cfg(any(test, feature = "std"))]
-impl ::std::error::Error for ::Error {
-    fn cause(&self) -> Option<&::std::error::Error> { None }
-    fn description(&self) -> &str { "`std::error::description` is deprecated" }
-}
-
-#[cfg(any(test, feature = "std"))]
-impl ::std::error::Error for ::hex::Error {
-    fn cause(&self) -> Option<&::std::error::Error> { None }
-    fn description(&self) -> &str { "`std::error::description` is deprecated" }
-}
-
-impl literacy::Write for sha1::HashEngine {
-    type Error = ();
-
-    fn write(&mut self, buf: &[u8]) -> ::core::result::Result<usize, ()>  {
-        self.input(buf);
-        Ok(buf.len())
-    }
+macro_rules! write_impl {
+    ($HashEngine: ty) => {
+        impl literacy::Write for $HashEngine {
+            type Error = ();
+
+            fn write(&mut self, buf: &[u8]) -> ::core::result::Result<usize, ()>  {
+                self.input(buf);
+                Ok(buf.len())
+            }
 
-    fn write_all(&mut self, buf: &[u8]) -> ::core::result::Result<(), ()> {
-        self.write(buf)?;
-        Ok(())
-    }
+            fn write_all(&mut self, buf: &[u8]) -> ::core::result::Result<(), ()> {
+                self.write(buf)?;
+                Ok(())
+            }
 
-    fn flush(&mut self) -> ::core::result::Result<(), ()> { Ok(()) }
-}
+            fn flush(&mut self) -> ::core::result::Result<(), ()> { Ok(()) }
+        }
 
-impl literacy::Write for sha256::HashEngine {
-    type Error = ();
+        impl literacy::Write for &mut $HashEngine {
+            type Error = ();
 
-    fn write(&mut self, buf: &[u8]) -> ::core::result::Result<usize, ()>  {
-        self.input(buf);
-        Ok(buf.len())
-    }
+            fn write(&mut self, buf: &[u8]) -> ::core::result::Result<usize, ()>  {
+                self.input(buf);
+                Ok(buf.len())
+            }
 
-    fn write_all(&mut self, buf: &[u8]) -> ::core::result::Result<(), ()> {
-        self.write(buf)?;
-        Ok(())
-    }
+            fn write_all(&mut self, buf: &[u8]) -> ::core::result::Result<(), ()> {
+                self.write(buf)?;
+                Ok(())
+            }
 
-    fn flush(&mut self) -> ::core::result::Result<(), ()>  { Ok(()) }
+            fn flush(&mut self) -> ::core::result::Result<(), ()> { Ok(()) }
+        }
+    };
 }
 
-impl literacy::Write for sha512::HashEngine {
-    type Error = ();
-
-    fn write(&mut self, buf: &[u8]) -> ::core::result::Result<usize, ()>  {
-        self.input(buf);
-        Ok(buf.len())
-    }
-
-    fn write_all(&mut self, buf: &[u8]) -> ::core::result::Result<(), ()> {
-        self.write(buf)?;
-        Ok(())
-    }
-
-    fn flush(&mut self) -> ::core::result::Result<(), ()>  { Ok(()) }
+#[cfg(any(test, feature = "std"))]
+impl ::std::error::Error for ::Error {
+    fn cause(&self) -> Option<&::std::error::Error> { None }
+    fn description(&self) -> &str { "`std::error::description` is deprecated" }
 }
 
-impl literacy::Write for ripemd160::HashEngine {
-    type Error = ();
-
-    fn write(&mut self, buf: &[u8]) -> ::core::result::Result<usize, ()>  {
-        self.input(buf);
-        Ok(buf.len())
-    }
-
-    fn write_all(&mut self, buf: &[u8]) -> ::core::result::Result<(), ()> {
-        self.write(buf)?;
-        Ok(())
-    }
-
-    fn flush(&mut self) -> ::core::result::Result<(), ()>  { Ok(()) }
+#[cfg(any(test, feature = "std"))]
+impl ::std::error::Error for ::hex::Error {
+    fn cause(&self) -> Option<&::std::error::Error> { None }
+    fn description(&self) -> &str { "`std::error::description` is deprecated" }
 }
 
-impl literacy::Write for siphash24::HashEngine {
-    type Error = ();
-
-    fn write(&mut self, buf: &[u8]) -> ::core::result::Result<usize, ()> {
-        self.input(buf);
-        Ok(buf.len())
-    }
-
-    fn write_all(&mut self, buf: &[u8]) -> ::core::result::Result<(), ()> {
-        self.write(buf)?;
-        Ok(())
-    }
-
-    fn flush(&mut self) -> ::core::result::Result<(), ()>  { Ok(()) }
-}
+write_impl!(sha1::HashEngine);
+write_impl!(sha256::HashEngine);
+write_impl!(sha512::HashEngine);
+write_impl!(ripemd160::HashEngine);
+write_impl!(siphash24::HashEngine);
 
 #[cfg(test)]
 mod tests {