diff options
Diffstat (limited to 'tvix/eval/src/value/attrs.rs')
-rw-r--r-- | tvix/eval/src/value/attrs.rs | 122 |
1 files changed, 68 insertions, 54 deletions
diff --git a/tvix/eval/src/value/attrs.rs b/tvix/eval/src/value/attrs.rs index 0551fe20d905..6802d195e8e2 100644 --- a/tvix/eval/src/value/attrs.rs +++ b/tvix/eval/src/value/attrs.rs @@ -18,7 +18,7 @@ use super::Value; #[cfg(test)] mod tests; -#[derive(Clone, Debug)] +#[derive(Clone, Debug, PartialEq)] enum AttrsRep { Empty, Map(BTreeMap<NixString, Value>), @@ -71,7 +71,7 @@ impl AttrsRep { } #[repr(transparent)] -#[derive(Clone, Debug)] +#[derive(Clone, Debug, PartialEq)] pub struct NixAttrs(AttrsRep); impl Display for NixAttrs { @@ -97,58 +97,6 @@ impl Display for NixAttrs { } } -impl PartialEq for NixAttrs { - fn eq(&self, other: &Self) -> bool { - match (&self.0, &other.0) { - (AttrsRep::Empty, AttrsRep::Empty) => true, - - // It is possible to create an empty attribute set that - // has Map representation like so: ` { ${null} = 1; }`. - // - // Preventing this would incur a cost on all attribute set - // construction (we'd have to check the actual number of - // elements after key construction). In practice this - // probably does not happen, so it's better to just bite - // the bullet and implement this branch. - (AttrsRep::Empty, AttrsRep::Map(map)) | (AttrsRep::Map(map), AttrsRep::Empty) => { - map.is_empty() - } - - // Other specialised representations (KV ...) definitely - // do not match `Empty`. - (AttrsRep::Empty, _) | (_, AttrsRep::Empty) => false, - - ( - AttrsRep::KV { - name: n1, - value: v1, - }, - AttrsRep::KV { - name: n2, - value: v2, - }, - ) => n1 == n2 && v1 == v2, - - (AttrsRep::Map(map), AttrsRep::KV { name, value }) - | (AttrsRep::KV { name, value }, AttrsRep::Map(map)) => { - if map.len() != 2 { - return false; - } - - if let (Some(m_name), Some(m_value)) = - (map.get(&NixString::NAME), map.get(&NixString::VALUE)) - { - return name == m_name && value == m_value; - } - - false - } - - (AttrsRep::Map(m1), AttrsRep::Map(m2)) => m1 == m2, - } - } -} - #[cfg(feature = "arbitrary")] mod arbitrary { use super::*; @@ -337,6 +285,72 @@ impl NixAttrs { pub(crate) fn from_map(map: BTreeMap<NixString, Value>) -> Self { NixAttrs(AttrsRep::Map(map)) } + + /// Compare `self` against `other` for equality using Nix equality semantics + pub fn nix_eq(&self, other: &Self) -> Result<bool, ErrorKind> { + match (&self.0, &other.0) { + (AttrsRep::Empty, AttrsRep::Empty) => Ok(true), + + // It is possible to create an empty attribute set that + // has Map representation like so: ` { ${null} = 1; }`. + // + // Preventing this would incur a cost on all attribute set + // construction (we'd have to check the actual number of + // elements after key construction). In practice this + // probably does not happen, so it's better to just bite + // the bullet and implement this branch. + (AttrsRep::Empty, AttrsRep::Map(map)) | (AttrsRep::Map(map), AttrsRep::Empty) => { + Ok(map.is_empty()) + } + + // Other specialised representations (KV ...) definitely + // do not match `Empty`. + (AttrsRep::Empty, _) | (_, AttrsRep::Empty) => Ok(false), + + ( + AttrsRep::KV { + name: n1, + value: v1, + }, + AttrsRep::KV { + name: n2, + value: v2, + }, + ) => Ok(n1.nix_eq(n2)? && v1.nix_eq(v2)?), + + (AttrsRep::Map(map), AttrsRep::KV { name, value }) + | (AttrsRep::KV { name, value }, AttrsRep::Map(map)) => { + if map.len() != 2 { + return Ok(false); + } + + if let (Some(m_name), Some(m_value)) = + (map.get(&NixString::NAME), map.get(&NixString::VALUE)) + { + return Ok(name.nix_eq(m_name)? && value.nix_eq(m_value)?); + } + + Ok(false) + } + + (AttrsRep::Map(m1), AttrsRep::Map(m2)) => { + if m1.len() != m2.len() { + return Ok(false); + } + + for (k, v1) in m1 { + if let Some(v2) = m2.get(k) { + if !v1.nix_eq(v2)? { + return Ok(false); + } + } else { + return Ok(false); + } + } + Ok(true) + } + } + } } /// In Nix, name/value attribute pairs are frequently constructed from |