diff options
Diffstat (limited to 'tvix/eval/src/value/attrs.rs')
| -rw-r--r-- | tvix/eval/src/value/attrs.rs | 93 |
1 files changed, 49 insertions, 44 deletions
diff --git a/tvix/eval/src/value/attrs.rs b/tvix/eval/src/value/attrs.rs index e7da6ee621d0..9204a5bb955a 100644 --- a/tvix/eval/src/value/attrs.rs +++ b/tvix/eval/src/value/attrs.rs @@ -18,29 +18,55 @@ use super::Value; mod tests; #[derive(Clone, Debug)] -pub enum NixAttrs { +enum AttrsRep { Empty, Map(BTreeMap<NixString, Value>), KV { name: Value, value: Value }, } +impl AttrsRep { + /// Retrieve reference to a mutable map inside of an attrs, + /// optionally changing the representation if required. + fn map_mut(&mut self) -> &mut BTreeMap<NixString, Value> { + match self { + AttrsRep::Map(m) => m, + + AttrsRep::Empty => { + *self = AttrsRep::Map(BTreeMap::new()); + self.map_mut() + } + + AttrsRep::KV { name, value } => { + *self = AttrsRep::Map(BTreeMap::from([ + ("name".into(), std::mem::replace(name, Value::Blackhole)), + ("value".into(), std::mem::replace(value, Value::Blackhole)), + ])); + self.map_mut() + } + } + } +} + +#[derive(Clone, Debug)] +pub struct NixAttrs(AttrsRep); + impl Display for NixAttrs { fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { f.write_str("{ ")?; - match self { - NixAttrs::KV { name, value } => { + match &self.0 { + AttrsRep::KV { name, value } => { f.write_fmt(format_args!("name = {}; ", name))?; f.write_fmt(format_args!("value = {}; ", value))?; } - NixAttrs::Map(map) => { + AttrsRep::Map(map) => { for (name, value) in map.iter() { f.write_fmt(format_args!("{} = {}; ", name.ident_str(), value))?; } } - NixAttrs::Empty => { /* no values to print! */ } + AttrsRep::Empty => { /* no values to print! */ } } f.write_str("}") @@ -56,22 +82,22 @@ impl PartialEq for NixAttrs { impl NixAttrs { // Update one attribute set with the values of the other. pub fn update(&self, other: &Self) -> Self { - match (self, other) { + match (&self.0, &other.0) { // Short-circuit on some optimal cases: - (NixAttrs::Empty, NixAttrs::Empty) => NixAttrs::Empty, - (NixAttrs::Empty, _) => other.clone(), - (_, NixAttrs::Empty) => self.clone(), - (NixAttrs::KV { .. }, NixAttrs::KV { .. }) => other.clone(), + (AttrsRep::Empty, AttrsRep::Empty) => NixAttrs(AttrsRep::Empty), + (AttrsRep::Empty, _) => other.clone(), + (_, AttrsRep::Empty) => self.clone(), + (AttrsRep::KV { .. }, AttrsRep::KV { .. }) => other.clone(), // Slightly more advanced, but still optimised updates - (NixAttrs::Map(m), NixAttrs::KV { name, value }) => { + (AttrsRep::Map(m), AttrsRep::KV { name, value }) => { let mut m = m.clone(); m.insert(NixString::NAME, name.clone()); m.insert(NixString::VALUE, value.clone()); - NixAttrs::Map(m) + NixAttrs(AttrsRep::Map(m)) } - (NixAttrs::KV { name, value }, NixAttrs::Map(m)) => { + (AttrsRep::KV { name, value }, AttrsRep::Map(m)) => { let mut m = m.clone(); match m.entry(NixString::NAME) { @@ -94,36 +120,15 @@ impl NixAttrs { } }; - NixAttrs::Map(m) + NixAttrs(AttrsRep::Map(m)) } // Plain merge of maps. - (NixAttrs::Map(m1), NixAttrs::Map(m2)) => { + (AttrsRep::Map(m1), AttrsRep::Map(m2)) => { let mut m1 = m1.clone(); let mut m2 = m2.clone(); m1.append(&mut m2); - NixAttrs::Map(m1) - } - } - } - - /// Retrieve reference to a mutable map inside of an attrs, - /// optionally changing the representation if required. - fn map_mut(&mut self) -> &mut BTreeMap<NixString, Value> { - match self { - NixAttrs::Map(m) => m, - - NixAttrs::Empty => { - *self = NixAttrs::Map(BTreeMap::new()); - self.map_mut() - } - - NixAttrs::KV { name, value } => { - *self = NixAttrs::Map(BTreeMap::from([ - ("name".into(), std::mem::replace(name, Value::Blackhole)), - ("value".into(), std::mem::replace(value, Value::Blackhole)), - ])); - self.map_mut() + NixAttrs(AttrsRep::Map(m1)) } } } @@ -140,7 +145,7 @@ impl NixAttrs { // Optimisation: Empty attribute set if count == 0 { - return Ok(NixAttrs::Empty); + return Ok(NixAttrs(AttrsRep::Empty)); } // Optimisation: KV pattern @@ -151,7 +156,7 @@ impl NixAttrs { } // TODO(tazjin): extend_reserve(count) (rust#72631) - let mut attrs = NixAttrs::Map(BTreeMap::new()); + let mut attrs = NixAttrs(AttrsRep::Map(BTreeMap::new())); for _ in 0..count { let value = stack_slice.pop().unwrap(); @@ -217,16 +222,16 @@ fn attempt_optimise_kv(slice: &mut [Value]) -> Option<NixAttrs> { } }; - Some(NixAttrs::KV { + Some(NixAttrs(AttrsRep::KV { name: std::mem::replace(&mut slice[name_idx], Value::Blackhole), value: std::mem::replace(&mut slice[value_idx], Value::Blackhole), - }) + })) } // Set an attribute on an in-construction attribute set, while // checking against duplicate keys. fn set_attr(attrs: &mut NixAttrs, key: NixString, value: Value) -> EvalResult<()> { - let attrs = attrs.map_mut(); + let attrs = attrs.0.map_mut(); let entry = attrs.entry(key); match entry { @@ -261,7 +266,7 @@ fn set_nested_attr( return set_attr(attrs, key, value); } - let attrs = attrs.map_mut(); + let attrs = attrs.0.map_mut(); let entry = attrs.entry(key); // If there is not we go one step further down, in which case we @@ -273,7 +278,7 @@ fn set_nested_attr( match entry { // Vacant entry -> new attribute set is needed. std::collections::btree_map::Entry::Vacant(entry) => { - let mut map = NixAttrs::Map(BTreeMap::new()); + let mut map = NixAttrs(AttrsRep::Map(BTreeMap::new())); // TODO(tazjin): technically recursing further is not // required, we can create the whole hierarchy here, but |