Improve the ScriptHash and WScriptHash types

Improve the script hash types by doing:

- Define the types in the `crypto::script` module
- Put the From impls directly below the type definitions

Keep the current crate level re-export so this does not impact the
public API _if_ people are using the re-export but is still a breaking
change.

bitcoin/src/address.rs

@@ -43,9 +43,8 @@ use crate::blockdata::constants::{
 };
 use crate::blockdata::script::witness_program::{self, WitnessProgram};
 use crate::blockdata::script::witness_version::{self, WitnessVersion};
-use crate::blockdata::script::{self, Script, ScriptBuf};
+use crate::blockdata::script::{self, Script, ScriptBuf, ScriptHash};
 use crate::crypto::key::{PubkeyHash, PublicKey, TapTweak, TweakedPublicKey, UntweakedPublicKey};
-use crate::hash_types::ScriptHash;
 use crate::network::Network;
 use crate::prelude::*;
 use crate::taproot::TapNodeHash;

bitcoin/src/blockdata/script/borrowed.rs

@@ -14,9 +14,9 @@ use crate::blockdata::opcodes::{self};
 use crate::blockdata::script::witness_version::WitnessVersion;
 use crate::blockdata::script::{
     bytes_to_asm_fmt, Builder, Instruction, InstructionIndices, Instructions, ScriptBuf,
+    ScriptHash, WScriptHash,
 };
 use crate::consensus::Encodable;
-use crate::hash_types::{ScriptHash, WScriptHash};
 use crate::key::{PublicKey, UntweakedPublicKey};
 use crate::policy::DUST_RELAY_TX_FEE;
 use crate::prelude::*;

bitcoin/src/blockdata/script/mod.rs

@@ -55,13 +55,13 @@ use core::cmp::Ordering;
 use core::fmt;
 use core::ops::{Deref, DerefMut};
 
+use hashes::{hash160, sha256};
 #[cfg(feature = "serde")]
 use serde;
 
 use crate::blockdata::opcodes::all::*;
 use crate::blockdata::opcodes::{self};
 use crate::consensus::{encode, Decodable, Encodable};
-use crate::hash_types::{ScriptHash, WScriptHash};
 use crate::prelude::*;
 use crate::{io, OutPoint};
 
@@ -81,6 +81,38 @@ pub use self::instruction::*;
 pub use self::owned::*;
 pub use self::push_bytes::*;
 
+hashes::hash_newtype! {
+    /// A hash of Bitcoin Script bytecode.
+    pub struct ScriptHash(hash160::Hash);
+    /// SegWit version of a Bitcoin Script bytecode hash.
+    pub struct WScriptHash(sha256::Hash);
+}
+crate::hash_types::impl_asref_push_bytes!(ScriptHash, WScriptHash);
+
+impl From<ScriptBuf> for ScriptHash {
+    fn from(script: ScriptBuf) -> ScriptHash { script.script_hash() }
+}
+
+impl From<&ScriptBuf> for ScriptHash {
+    fn from(script: &ScriptBuf) -> ScriptHash { script.script_hash() }
+}
+
+impl From<&Script> for ScriptHash {
+    fn from(script: &Script) -> ScriptHash { script.script_hash() }
+}
+
+impl From<ScriptBuf> for WScriptHash {
+    fn from(script: ScriptBuf) -> WScriptHash { script.wscript_hash() }
+}
+
+impl From<&ScriptBuf> for WScriptHash {
+    fn from(script: &ScriptBuf) -> WScriptHash { script.wscript_hash() }
+}
+
+impl From<&Script> for WScriptHash {
+    fn from(script: &Script) -> WScriptHash { script.wscript_hash() }
+}
+
 /// Encodes an integer in script(minimal CScriptNum) format.
 ///
 /// Writes bytes into the buffer and returns the number of bytes written.
@@ -304,30 +336,6 @@ impl From<ScriptBuf> for Vec<u8> {
     fn from(v: ScriptBuf) -> Self { v.0 }
 }
 
-impl From<ScriptBuf> for ScriptHash {
-    fn from(script: ScriptBuf) -> ScriptHash { script.script_hash() }
-}
-
-impl From<&ScriptBuf> for ScriptHash {
-    fn from(script: &ScriptBuf) -> ScriptHash { script.script_hash() }
-}
-
-impl From<&Script> for ScriptHash {
-    fn from(script: &Script) -> ScriptHash { script.script_hash() }
-}
-
-impl From<ScriptBuf> for WScriptHash {
-    fn from(script: ScriptBuf) -> WScriptHash { script.wscript_hash() }
-}
-
-impl From<&ScriptBuf> for WScriptHash {
-    fn from(script: &ScriptBuf) -> WScriptHash { script.wscript_hash() }
-}
-
-impl From<&Script> for WScriptHash {
-    fn from(script: &Script) -> WScriptHash { script.wscript_hash() }
-}
-
 impl AsRef<Script> for Script {
     #[inline]
     fn as_ref(&self) -> &Script { self }

bitcoin/src/blockdata/script/owned.rs

@@ -9,8 +9,9 @@ use crate::blockdata::opcodes::all::*;
 use crate::blockdata::opcodes::{self};
 use crate::blockdata::script::witness_program::WitnessProgram;
 use crate::blockdata::script::witness_version::WitnessVersion;
-use crate::blockdata::script::{opcode_to_verify, Builder, Instruction, PushBytes, Script};
-use crate::hash_types::{ScriptHash, WScriptHash};
+use crate::blockdata::script::{
+    opcode_to_verify, Builder, Instruction, PushBytes, Script, ScriptHash, WScriptHash,
+};
 use crate::key::{
     PubkeyHash, PublicKey, TapTweak, TweakedPublicKey, UntweakedPublicKey, WPubkeyHash,
 };

bitcoin/src/hash_types.rs

@@ -52,7 +52,7 @@ pub use newtypes::*;
 
 #[rustfmt::skip]
 mod newtypes {
-    use hashes::{sha256, sha256d, hash160, hash_newtype};
+    use hashes::{sha256d, hash160, hash_newtype};
 
     hash_newtype! {
         /// A bitcoin transaction hash/transaction ID.
@@ -69,11 +69,6 @@ mod newtypes {
         /// A bitcoin block hash.
         pub struct BlockHash(sha256d::Hash);
 
-        /// A hash of Bitcoin Script bytecode.
-        pub struct ScriptHash(hash160::Hash);
-        /// SegWit version of a Bitcoin Script bytecode hash.
-        pub struct WScriptHash(sha256::Hash);
-
         /// A hash of the Merkle tree branch or root for transactions
         pub struct TxMerkleNode(sha256d::Hash);
         /// A hash corresponding to the Merkle tree root for witness data
@@ -98,6 +93,4 @@ mod newtypes {
 
     impl_hashencode!(FilterHash);
     impl_hashencode!(FilterHeader);
-
-    impl_asref_push_bytes!(ScriptHash, WScriptHash);
 }

bitcoin/src/lib.rs

@@ -135,7 +135,7 @@ pub use crate::blockdata::fee_rate::FeeRate;
 pub use crate::blockdata::locktime::{self, absolute, relative};
 pub use crate::blockdata::script::witness_program::{self, WitnessProgram};
 pub use crate::blockdata::script::witness_version::{self, WitnessVersion};
-pub use crate::blockdata::script::{self, Script, ScriptBuf};
+pub use crate::blockdata::script::{self, Script, ScriptBuf, ScriptHash, WScriptHash};
 pub use crate::blockdata::transaction::{self, OutPoint, Sequence, Transaction, TxIn, TxOut};
 pub use crate::blockdata::weight::Weight;
 pub use crate::blockdata::witness::{self, Witness};
@@ -143,7 +143,7 @@ pub use crate::blockdata::{constants, opcodes};
 pub use crate::consensus::encode::VarInt;
 pub use crate::crypto::key::{self, PrivateKey, PubkeyHash, PublicKey, WPubkeyHash};
 pub use crate::crypto::{ecdsa, sighash};
-pub use crate::hash_types::{BlockHash, ScriptHash, Txid, WScriptHash, Wtxid};
+pub use crate::hash_types::{BlockHash, Txid, Wtxid};
 pub use crate::merkle_tree::MerkleBlock;
 pub use crate::network::Network;
 pub use crate::pow::{CompactTarget, Target, Work};