Implement hashing for types

crates/rune/Cargo.toml

@@ -25,7 +25,7 @@ byte-code = ["alloc", "musli-storage"]
 capture-io = ["alloc", "parking_lot"]
 disable-io = ["alloc"]
 fmt = ["alloc"]
-std = ["num/std", "serde/std", "rune-core/std", "musli/std", "musli-storage/std", "alloc", "anyhow"]
+std = ["num/std", "serde/std", "rune-core/std", "musli/std", "musli-storage/std", "alloc", "anyhow", "lazy_static"]
 alloc = []
 
 [dependencies]
@@ -74,6 +74,7 @@ similar = { version = "2.2.1", optional = true, features = ["inline", "bytes"] }
 sha2 = { version = "0.10.6", optional = true }
 base64 = { version = "0.21.0", optional = true }
 rand = { version = "0.8.5", optional = true }
+lazy_static = { version = "1.4.0", optional = true }
 
 [dev-dependencies]
 tokio = { version = "1.28.1", features = ["full"] }

crates/rune/src/compile/context.rs

@@ -139,6 +139,7 @@ impl Context {
         this.install(crate::modules::any::module()?)?;
         this.install(crate::modules::bytes::module()?)?;
         this.install(crate::modules::char::module()?)?;
+        this.install(crate::modules::hash::module()?)?;
         this.install(crate::modules::cmp::module()?)?;
         this.install(crate::modules::collections::module()?)?;
         this.install(crate::modules::f64::module()?)?;

crates/rune/src/modules.rs

@@ -18,6 +18,7 @@ pub mod f64;
 pub mod fmt;
 pub mod future;
 pub mod generator;
+pub mod hash;
 pub mod i64;
 #[cfg(feature = "std")]
 pub mod io;

crates/rune/src/modules/hash.rs

@@ -0,0 +1,16 @@
+//! The `std::hash` module.
+
+use crate as rune;
+#[cfg(feature = "std")]
+use crate::runtime::Hasher;
+use crate::{ContextError, Module};
+
+#[rune::module(::std::hash)]
+/// Types for dealing with hashing in Rune.
+pub fn module() -> Result<Module, ContextError> {
+    #[allow(unused_mut)]
+    let mut module = Module::from_meta(self::module_meta);
+    #[cfg(feature = "std")]
+    module.ty::<Hasher>()?;
+    Ok(module)
+}

crates/rune/src/modules/ops.rs

@@ -3,11 +3,15 @@
 use core::cmp::Ordering;
 
 use crate as rune;
+#[cfg(feature = "std")]
+use crate::runtime::Hasher;
 use crate::runtime::{
     ControlFlow, EnvProtocolCaller, Function, Generator, GeneratorState, Iterator, Range,
     RangeFrom, RangeFull, RangeInclusive, RangeTo, RangeToInclusive, Value, Vm, VmResult,
 };
 use crate::{ContextError, Module};
+#[cfg(feature = "std")]
+use std::collections::hash_map::RandomState;
 
 #[rune::module(::std::ops)]
 /// Overloadable operators.
@@ -96,6 +100,8 @@ pub fn module() -> Result<Module, ContextError> {
     m.function_meta(eq)?;
     m.function_meta(partial_cmp)?;
     m.function_meta(cmp)?;
+    #[cfg(feature = "std")]
+    m.function_meta(hash)?;
     Ok(m)
 }
 
@@ -201,6 +207,47 @@ fn cmp(lhs: Value, rhs: Value) -> VmResult<Ordering> {
     Value::cmp(&lhs, &rhs)
 }
 
+#[cfg(feature = "std")]
+lazy_static::lazy_static! {
+    static ref STATE: RandomState = RandomState::new();
+}
+
+/// Hashes the given value.
+///
+/// For non-builtin types this uses the [`HASH`] protocol.
+///
+/// # Hash stability
+///
+/// The hash is guaranteed to be stable within a single virtual machine
+/// invocation, but not across virtual machines. So returning the hash from one
+/// and calculating it in another using an identical value is not guaranteed to
+/// produce the same hash.
+///
+/// # Panics
+///
+/// Panics if we try to generate a hash from an unhashable value.
+///
+/// # Examples
+///
+/// ```rune
+/// use std::ops::hash;
+///
+/// assert_eq!(hash([1, 2]), hash((1, 2)));
+/// ```
+#[rune::function]
+#[cfg(feature = "std")]
+fn hash(value: Value) -> VmResult<i64> {
+    let mut hasher = Hasher::new_with(&*STATE);
+
+    vm_try!(Value::hash_with(
+        &value,
+        &mut hasher,
+        &mut EnvProtocolCaller
+    ));
+
+    VmResult::Ok(hasher.finish() as i64)
+}
+
 /// Advance a generator producing the next value yielded.
 ///
 /// Unlike [`Generator::resume`], this can only consume the yielded values.

crates/rune/src/modules/tuple.rs

@@ -3,6 +3,8 @@
 use core::cmp::Ordering;
 
 use crate as rune;
+#[cfg(feature = "std")]
+use crate::runtime::Hasher;
 use crate::runtime::{EnvProtocolCaller, Iterator, Ref, Tuple, Value, Vec, VmResult};
 use crate::{ContextError, Module};
 
@@ -20,6 +22,8 @@ pub fn module() -> Result<Module, ContextError> {
     m.function_meta(eq)?;
     m.function_meta(partial_cmp)?;
     m.function_meta(cmp)?;
+    #[cfg(feature = "std")]
+    m.function_meta(hash)?;
     Ok(m)
 }
 
@@ -174,3 +178,20 @@ fn partial_cmp(this: &Tuple, other: &Tuple) -> VmResult<Option<Ordering>> {
 fn cmp(this: &Tuple, other: &Tuple) -> VmResult<Ordering> {
     Vec::cmp_with(this, other, &mut EnvProtocolCaller)
 }
+
+/// Calculate a hash for a tuple.
+///
+/// # Examples
+///
+/// ```rune
+/// use std::ops::hash;
+///
+/// assert_eq!(hash((0, 2, 3)), hash((0, 2, 3)));
+/// // Note: this is not guaranteed to be true forever, but it's true right now.
+/// assert_eq!(hash((0, 2, 3)), hash([0, 2, 3]));
+/// ```
+#[rune::function(instance, protocol = HASH)]
+#[cfg(feature = "std")]
+fn hash(this: &Tuple, hasher: &mut Hasher) -> VmResult<()> {
+    Tuple::hash_with(this, hasher, &mut EnvProtocolCaller)
+}

crates/rune/src/modules/vec.rs

@@ -4,6 +4,8 @@ use core::cmp::Ordering;
 use core::fmt;
 
 use crate as rune;
+#[cfg(feature = "std")]
+use crate::runtime::Hasher;
 use crate::runtime::{
     EnvProtocolCaller, Formatter, Function, Iterator, Ref, TypeOf, Value, Vec, VmErrorKind,
     VmResult,
@@ -54,6 +56,8 @@ pub fn module() -> Result<Module, ContextError> {
     m.function_meta(eq)?;
     m.function_meta(partial_cmp)?;
     m.function_meta(cmp)?;
+    #[cfg(feature = "std")]
+    m.function_meta(hash)?;
     Ok(m)
 }
 
@@ -615,3 +619,18 @@ fn partial_cmp(this: &Vec, other: &Vec) -> VmResult<Option<Ordering>> {
 fn cmp(this: &Vec, other: &Vec) -> VmResult<Ordering> {
     Vec::cmp_with(this, other, &mut EnvProtocolCaller)
 }
+
+/// Calculate the hash of a vector.
+///
+/// # Examples
+///
+/// ```rune
+/// use std::ops::hash;
+///
+/// assert_eq!(hash([0, 2, 3]), hash([0, 2, 3]));
+/// ```
+#[rune::function(instance, protocol = HASH)]
+#[cfg(feature = "std")]
+fn hash(this: &Vec, hasher: &mut Hasher) -> VmResult<()> {
+    Vec::hash_with(this, hasher, &mut EnvProtocolCaller)
+}

crates/rune/src/runtime/tuple.rs

@@ -9,6 +9,8 @@ use crate::runtime::{
     ConstValue, FromValue, Mut, RawMut, RawRef, Ref, Shared, ToValue, UnsafeToMut, UnsafeToRef,
     Value, VmErrorKind, VmResult,
 };
+#[cfg(feature = "std")]
+use crate::runtime::{Hasher, ProtocolCaller};
 use crate::Any;
 
 /// The type of a tuple slice.
@@ -44,6 +46,19 @@ impl Tuple {
 
         VmResult::Ok(Some(vm_try!(T::from_value(value))))
     }
+
+    #[cfg(feature = "std")]
+    pub(crate) fn hash_with(
+        &self,
+        hasher: &mut Hasher,
+        caller: &mut impl ProtocolCaller,
+    ) -> VmResult<()> {
+        for value in self.values.iter() {
+            vm_try!(value.hash_with(hasher, caller));
+        }
+
+        VmResult::Ok(())
+    }
 }
 
 impl ops::Deref for Tuple {

crates/rune/src/runtime/value.rs

@@ -12,15 +12,15 @@ use crate::no_std::vec;
 
 use crate::compile::ItemBuf;
 use crate::runtime::vm::CallResult;
-#[cfg(feature = "std")]
-use crate::runtime::Hasher;
 use crate::runtime::{
     AccessKind, AnyObj, Bytes, ConstValue, ControlFlow, EnvProtocolCaller, Format, Formatter,
     FromValue, FullTypeOf, Function, Future, Generator, GeneratorState, Iterator, MaybeTypeOf, Mut,
     Object, OwnedTuple, Protocol, ProtocolCaller, Range, RangeFrom, RangeFull, RangeInclusive,
     RangeTo, RangeToInclusive, RawMut, RawRef, Ref, Shared, Stream, ToValue, Type, TypeInfo,
     Variant, Vec, Vm, VmError, VmErrorKind, VmIntegerRepr, VmResult,
 };
+#[cfg(feature = "std")]
+use crate::runtime::{Hasher, Tuple};
 use crate::{Any, Hash};
 
 use serde::{de, ser, Deserialize, Serialize};
@@ -1339,6 +1339,12 @@ impl Value {
         })
     }
 
+    /// Hash the current value.
+    #[cfg(feature = "std")]
+    pub fn hash(&self, hasher: &mut Hasher) -> VmResult<()> {
+        self.hash_with(hasher, &mut EnvProtocolCaller)
+    }
+
     /// Hash the current value.
     #[cfg(feature = "std")]
     pub(crate) fn hash_with(
@@ -1377,6 +1383,14 @@ impl Value {
                 hasher.write(&bytes);
                 return VmResult::Ok(());
             }
+            Value::Tuple(tuple) => {
+                let tuple = vm_try!(tuple.borrow_ref());
+                return Tuple::hash_with(&tuple, hasher, caller);
+            }
+            Value::Vec(vec) => {
+                let vec = vm_try!(vec.borrow_ref());
+                return Vec::hash_with(&vec, hasher, caller);
+            }
             value => {
                 match vm_try!(caller.try_call_protocol_fn(Protocol::HASH, value.clone(), (hasher,)))
                 {

crates/rune/src/runtime/vec.rs

@@ -11,6 +11,8 @@ use crate::no_std::prelude::*;
 use crate::no_std::vec;
 
 use crate as rune;
+#[cfg(feature = "std")]
+use crate::runtime::Hasher;
 use crate::runtime::{
     Formatter, FromValue, Iterator, ProtocolCaller, RawRef, Ref, Shared, ToValue, UnsafeToRef,
     Value, VmErrorKind, VmResult,
@@ -379,6 +381,19 @@ impl Vec {
 
         VmResult::Ok(Some(Value::vec(values.to_vec())))
     }
+
+    #[cfg(feature = "std")]
+    pub(crate) fn hash_with(
+        &self,
+        hasher: &mut Hasher,
+        caller: &mut impl ProtocolCaller,
+    ) -> VmResult<()> {
+        for value in self.inner.iter() {
+            vm_try!(value.hash_with(hasher, caller));
+        }
+
+        VmResult::Ok(())
+    }
 }
 
 impl fmt::Debug for Vec {