use itertools::Itertools; use serde_cbor::value::value as cbor; use std::iter::FromIterator; use dhall_syntax::map::DupTreeMap; use dhall_syntax::{ rc, Expr, ExprF, FilePrefix, Hash, Import, ImportLocation, ImportMode, Integer, InterpolatedText, Label, Natural, Scheme, URL, V, }; use crate::error::{DecodeError, EncodeError}; use crate::phase::DecodedExpr; pub(crate) fn decode(data: &[u8]) -> Result { match serde_cbor::de::from_slice(data) { Ok(v) => cbor_value_to_dhall(&v), Err(e) => Err(DecodeError::CBORError(e)), } } pub(crate) fn encode(expr: &Expr) -> Result, EncodeError> { serde_cbor::ser::to_vec(&Serialize::Expr(expr)) .map_err(|e| EncodeError::CBORError(e)) } fn cbor_value_to_dhall(data: &cbor::Value) -> Result { use cbor::Value::*; use dhall_syntax::{BinOp, Builtin, Const}; use ExprF::*; Ok(rc(match data { String(s) => match Builtin::parse(s) { Some(b) => ExprF::Builtin(b), None => match s.as_str() { "True" => BoolLit(true), "False" => BoolLit(false), "Type" => Const(Const::Type), "Kind" => Const(Const::Kind), "Sort" => Const(Const::Sort), _ => Err(DecodeError::WrongFormatError("builtin".to_owned()))?, }, }, U64(n) => Var(V(Label::from("_"), *n as usize)), F64(x) => DoubleLit((*x).into()), Bool(b) => BoolLit(*b), Array(vec) => match vec.as_slice() { [String(l), U64(n)] => { if l.as_str() == "_" { Err(DecodeError::WrongFormatError( "`_` variable was encoded incorrectly".to_owned(), ))? } let l = Label::from(l.as_str()); Var(V(l, *n as usize)) } [U64(0), f, args..] => { if args.is_empty() { Err(DecodeError::WrongFormatError( "Function application must have at least one argument" .to_owned(), ))? } let mut f = cbor_value_to_dhall(&f)?; for a in args { let a = cbor_value_to_dhall(&a)?; f = rc(App(f, a)) } return Ok(f); } [U64(1), x, y] => { let x = cbor_value_to_dhall(&x)?; let y = cbor_value_to_dhall(&y)?; Lam(Label::from("_"), x, y) } [U64(1), String(l), x, y] => { if l.as_str() == "_" { Err(DecodeError::WrongFormatError( "`_` variable was encoded incorrectly".to_owned(), ))? } let x = cbor_value_to_dhall(&x)?; let y = cbor_value_to_dhall(&y)?; let l = Label::from(l.as_str()); Lam(l, x, y) } [U64(2), x, y] => { let x = cbor_value_to_dhall(&x)?; let y = cbor_value_to_dhall(&y)?; Pi(Label::from("_"), x, y) } [U64(2), String(l), x, y] => { if l.as_str() == "_" { Err(DecodeError::WrongFormatError( "`_` variable was encoded incorrectly".to_owned(), ))? } let x = cbor_value_to_dhall(&x)?; let y = cbor_value_to_dhall(&y)?; let l = Label::from(l.as_str()); Pi(l, x, y) } [U64(3), U64(n), x, y] => { let x = cbor_value_to_dhall(&x)?; let y = cbor_value_to_dhall(&y)?; use BinOp::*; let op = match n { 0 => BoolOr, 1 => BoolAnd, 2 => BoolEQ, 3 => BoolNE, 4 => NaturalPlus, 5 => NaturalTimes, 6 => TextAppend, 7 => ListAppend, 8 => RecursiveRecordMerge, 9 => RightBiasedRecordMerge, 10 => RecursiveRecordTypeMerge, 11 => ImportAlt, 12 => Equivalence, _ => { Err(DecodeError::WrongFormatError("binop".to_owned()))? } }; BinOp(op, x, y) } [U64(4), t] => { let t = cbor_value_to_dhall(&t)?; EmptyListLit(rc(App(rc(ExprF::Builtin(Builtin::List)), t))) } [U64(4), Null, rest..] => { let rest = rest .iter() .map(cbor_value_to_dhall) .collect::, _>>()?; NEListLit(rest) } [U64(5), Null, x] => { let x = cbor_value_to_dhall(&x)?; SomeLit(x) } // Old-style optional literals [U64(5), t] => { let t = cbor_value_to_dhall(&t)?; App(rc(ExprF::Builtin(Builtin::OptionalNone)), t) } [U64(5), t, x] => { let x = cbor_value_to_dhall(&x)?; let t = cbor_value_to_dhall(&t)?; Annot( rc(SomeLit(x)), rc(App(rc(ExprF::Builtin(Builtin::Optional)), t)), ) } [U64(6), x, y] => { let x = cbor_value_to_dhall(&x)?; let y = cbor_value_to_dhall(&y)?; Merge(x, y, None) } [U64(6), x, y, z] => { let x = cbor_value_to_dhall(&x)?; let y = cbor_value_to_dhall(&y)?; let z = cbor_value_to_dhall(&z)?; Merge(x, y, Some(z)) } [U64(7), Object(map)] => { let map = cbor_map_to_dhall_map(map)?; RecordType(map) } [U64(8), Object(map)] => { let map = cbor_map_to_dhall_map(map)?; RecordLit(map) } [U64(9), x, String(l)] => { let x = cbor_value_to_dhall(&x)?; let l = Label::from(l.as_str()); Field(x, l) } [U64(10), x, rest..] => { let x = cbor_value_to_dhall(&x)?; let labels = rest .iter() .map(|s| match s { String(s) => Ok(Label::from(s.as_str())), _ => Err(DecodeError::WrongFormatError( "projection".to_owned(), )), }) .collect::>()?; Projection(x, labels) } [U64(11), Object(map)] => { let map = cbor_map_to_dhall_opt_map(map)?; UnionType(map) } [U64(12), ..] => Err(DecodeError::WrongFormatError( "Union literals are not supported anymore".to_owned(), ))?, [U64(14), x, y, z] => { let x = cbor_value_to_dhall(&x)?; let y = cbor_value_to_dhall(&y)?; let z = cbor_value_to_dhall(&z)?; BoolIf(x, y, z) } [U64(15), U64(x)] => NaturalLit(*x as Natural), [U64(16), U64(x)] => IntegerLit(*x as Integer), [U64(16), I64(x)] => IntegerLit(*x as Integer), [U64(18), String(first), rest..] => { TextLit(InterpolatedText::from(( first.clone(), rest.iter() .tuples() .map(|(x, y)| { let x = cbor_value_to_dhall(&x)?; let y = match y { String(s) => s.clone(), _ => Err(DecodeError::WrongFormatError( "text".to_owned(), ))?, }; Ok((x, y)) }) .collect::>()?, ))) } [U64(19), t] => { let t = cbor_value_to_dhall(&t)?; Assert(t) } [U64(24), hash, U64(mode), U64(scheme), rest..] => { let mode = match mode { 0 => ImportMode::Code, 1 => ImportMode::RawText, 2 => ImportMode::Location, _ => Err(DecodeError::WrongFormatError(format!( "import/mode/unknown_mode: {:?}", mode )))?, }; let hash = match hash { Null => None, Bytes(bytes) => match bytes.as_slice() { [18, 32, rest..] => Some(Hash::SHA256(rest.to_vec())), _ => Err(DecodeError::WrongFormatError(format!( "import/hash/unknown_multihash: {:?}", bytes )))?, }, _ => Err(DecodeError::WrongFormatError( "import/hash/should_be_bytes".to_owned(), ))?, }; let mut rest = rest.iter(); let location = match scheme { 0 | 1 => { let scheme = match scheme { 0 => Scheme::HTTP, _ => Scheme::HTTPS, }; let headers = match rest.next() { Some(Null) => None, Some(x) => { let x = cbor_value_to_dhall(&x)?; Some(x) } _ => Err(DecodeError::WrongFormatError( "import/remote/headers".to_owned(), ))?, }; let authority = match rest.next() { Some(String(s)) => s.to_owned(), _ => Err(DecodeError::WrongFormatError( "import/remote/authority".to_owned(), ))?, }; let query = match rest.next_back() { Some(Null) => None, Some(String(s)) => Some(s.to_owned()), _ => Err(DecodeError::WrongFormatError( "import/remote/query".to_owned(), ))?, }; let path = rest .map(|s| match s.as_string() { Some(s) => Ok(s.clone()), None => Err(DecodeError::WrongFormatError( "import/remote/path".to_owned(), )), }) .collect::>()?; ImportLocation::Remote(URL { scheme, authority, path, query, headers, }) } 2 | 3 | 4 | 5 => { let prefix = match scheme { 2 => FilePrefix::Absolute, 3 => FilePrefix::Here, 4 => FilePrefix::Parent, 5 => FilePrefix::Home, _ => Err(DecodeError::WrongFormatError( "import/local/prefix".to_owned(), ))?, }; let path = rest .map(|s| match s.as_string() { Some(s) => Ok(s.clone()), None => Err(DecodeError::WrongFormatError( "import/local/path".to_owned(), )), }) .collect::>()?; ImportLocation::Local(prefix, path) } 6 => { let env = match rest.next() { Some(String(s)) => s.to_owned(), _ => Err(DecodeError::WrongFormatError( "import/env".to_owned(), ))?, }; ImportLocation::Env(env) } 7 => ImportLocation::Missing, _ => Err(DecodeError::WrongFormatError( "import/type".to_owned(), ))?, }; Import(dhall_syntax::Import { mode, hash, location, }) } [U64(25), bindings..] => { let mut tuples = bindings.iter().tuples(); let bindings = (&mut tuples) .map(|(x, t, v)| { let x = x.as_string().ok_or_else(|| { DecodeError::WrongFormatError( "let/label".to_owned(), ) })?; let x = Label::from(x.as_str()); let t = match t { Null => None, t => Some(cbor_value_to_dhall(&t)?), }; let v = cbor_value_to_dhall(&v)?; Ok((x, t, v)) }) .collect::, _>>()?; let expr = tuples.into_buffer().next().ok_or_else(|| { DecodeError::WrongFormatError("let/expr".to_owned()) })?; let expr = cbor_value_to_dhall(expr)?; return Ok(bindings .into_iter() .rev() .fold(expr, |acc, (x, t, v)| rc(Let(x, t, v, acc)))); } [U64(26), x, y] => { let x = cbor_value_to_dhall(&x)?; let y = cbor_value_to_dhall(&y)?; Annot(x, y) } [U64(28), x] => { let x = cbor_value_to_dhall(&x)?; EmptyListLit(x) } _ => Err(DecodeError::WrongFormatError(format!("{:?}", data)))?, }, _ => Err(DecodeError::WrongFormatError(format!("{:?}", data)))?, })) } fn cbor_map_to_dhall_map<'a, T>( map: impl IntoIterator, ) -> Result where T: FromIterator<(Label, DecodedExpr)>, { map.into_iter() .map(|(k, v)| -> Result<(_, _), _> { let k = k.as_string().ok_or_else(|| { DecodeError::WrongFormatError("map/key".to_owned()) })?; let v = cbor_value_to_dhall(v)?; Ok((Label::from(k.as_ref()), v)) }) .collect::>() } fn cbor_map_to_dhall_opt_map<'a, T>( map: impl IntoIterator, ) -> Result where T: FromIterator<(Label, Option)>, { map.into_iter() .map(|(k, v)| -> Result<(_, _), _> { let k = k.as_string().ok_or_else(|| { DecodeError::WrongFormatError("map/key".to_owned()) })?; let v = match v { cbor::Value::Null => None, _ => Some(cbor_value_to_dhall(v)?), }; Ok((Label::from(k.as_ref()), v)) }) .collect::>() } enum Serialize<'a, E> { Expr(&'a Expr), CBOR(cbor::Value), RecordMap(&'a DupTreeMap>), UnionMap(&'a DupTreeMap>>), } macro_rules! count { (@replace_with $_t:tt $sub:expr) => { $sub }; ($($tts:tt)*) => {0usize $(+ count!(@replace_with $tts 1usize))*}; } macro_rules! ser_seq { ($ser:expr; $($elt:expr),* $(,)?) => {{ use serde::ser::SerializeSeq; let count = count!($($elt)*); let mut ser_seq = $ser.serialize_seq(Some(count))?; $( ser_seq.serialize_element(&$elt)?; )* ser_seq.end() }}; } fn serialize_subexpr(ser: S, e: &Expr) -> Result where S: serde::ser::Serializer, { use cbor::Value::{String, I64, U64}; use dhall_syntax::Builtin; use dhall_syntax::ExprF::*; use std::iter::once; use self::Serialize::{RecordMap, UnionMap}; fn expr(x: &Expr) -> self::Serialize<'_, E> { self::Serialize::Expr(x) } let cbor = |v: cbor::Value| -> self::Serialize<'_, E> { self::Serialize::CBOR(v) }; let tag = |x: u64| cbor(U64(x)); let null = || cbor(cbor::Value::Null); let label = |l: &Label| cbor(cbor::Value::String(l.into())); match e.as_ref() { Const(c) => ser.serialize_str(&c.to_string()), Builtin(b) => ser.serialize_str(&b.to_string()), BoolLit(b) => ser.serialize_bool(*b), NaturalLit(n) => ser_seq!(ser; tag(15), U64(*n as u64)), IntegerLit(n) => ser_seq!(ser; tag(16), I64(*n as i64)), DoubleLit(n) => { let n: f64 = (*n).into(); ser.serialize_f64(n) } BoolIf(x, y, z) => ser_seq!(ser; tag(14), expr(x), expr(y), expr(z)), Var(V(l, n)) if l == &"_".into() => ser.serialize_u64(*n as u64), Var(V(l, n)) => ser_seq!(ser; label(l), U64(*n as u64)), Lam(l, x, y) if l == &"_".into() => { ser_seq!(ser; tag(1), expr(x), expr(y)) } Lam(l, x, y) => ser_seq!(ser; tag(1), label(l), expr(x), expr(y)), Pi(l, x, y) if l == &"_".into() => { ser_seq!(ser; tag(2), expr(x), expr(y)) } Pi(l, x, y) => ser_seq!(ser; tag(2), label(l), expr(x), expr(y)), Let(_, _, _, _) => { let (bound_e, bindings) = collect_nested_lets(e); let count = 1 + 3 * bindings.len() + 1; use serde::ser::SerializeSeq; let mut ser_seq = ser.serialize_seq(Some(count))?; ser_seq.serialize_element(&tag(25))?; for (l, t, v) in bindings { ser_seq.serialize_element(&label(l))?; match t { Some(t) => ser_seq.serialize_element(&expr(t))?, None => ser_seq.serialize_element(&null())?, } ser_seq.serialize_element(&expr(v))?; } ser_seq.serialize_element(&expr(bound_e))?; ser_seq.end() } App(_, _) => { let (f, args) = collect_nested_applications(e); ser.collect_seq( once(tag(0)) .chain(once(expr(f))) .chain(args.into_iter().rev().map(expr)), ) } Annot(x, y) => ser_seq!(ser; tag(26), expr(x), expr(y)), Assert(x) => ser_seq!(ser; tag(19), expr(x)), SomeLit(x) => ser_seq!(ser; tag(5), null(), expr(x)), EmptyListLit(x) => match x.as_ref() { App(f, a) => match f.as_ref() { ExprF::Builtin(Builtin::List) => ser_seq!(ser; tag(4), expr(a)), _ => ser_seq!(ser; tag(28), expr(x)), }, _ => ser_seq!(ser; tag(28), expr(x)), }, NEListLit(xs) => ser.collect_seq( once(tag(4)).chain(once(null())).chain(xs.iter().map(expr)), ), TextLit(xs) => { use dhall_syntax::InterpolatedTextContents::{Expr, Text}; ser.collect_seq(once(tag(18)).chain(xs.iter().map(|x| match x { Expr(x) => expr(x), Text(x) => cbor(String(x.clone())), }))) } RecordType(map) => ser_seq!(ser; tag(7), RecordMap(map)), RecordLit(map) => ser_seq!(ser; tag(8), RecordMap(map)), UnionType(map) => ser_seq!(ser; tag(11), UnionMap(map)), Field(x, l) => ser_seq!(ser; tag(9), expr(x), label(l)), BinOp(op, x, y) => { use dhall_syntax::BinOp::*; let op = match op { BoolOr => 0, BoolAnd => 1, BoolEQ => 2, BoolNE => 3, NaturalPlus => 4, NaturalTimes => 5, TextAppend => 6, ListAppend => 7, RecursiveRecordMerge => 8, RightBiasedRecordMerge => 9, RecursiveRecordTypeMerge => 10, ImportAlt => 11, Equivalence => 12, }; ser_seq!(ser; tag(3), U64(op), expr(x), expr(y)) } Merge(x, y, None) => ser_seq!(ser; tag(6), expr(x), expr(y)), Merge(x, y, Some(z)) => { ser_seq!(ser; tag(6), expr(x), expr(y), expr(z)) } Projection(x, ls) => ser.collect_seq( once(tag(10)) .chain(once(expr(x))) .chain(ls.iter().map(label)), ), Import(import) => serialize_import(ser, import), Embed(_) => unimplemented!( "An expression with resolved imports cannot be binary-encoded" ), } } fn serialize_import( ser: S, import: &Import>, ) -> Result where S: serde::ser::Serializer, { use cbor::Value::{Bytes, Null, U64}; use serde::ser::SerializeSeq; let count = 4 + match &import.location { ImportLocation::Remote(url) => 3 + url.path.len(), ImportLocation::Local(_, path) => path.len(), ImportLocation::Env(_) => 1, ImportLocation::Missing => 0, }; let mut ser_seq = ser.serialize_seq(Some(count))?; ser_seq.serialize_element(&U64(24))?; let hash = match &import.hash { None => Null, Some(Hash::SHA256(h)) => { let mut bytes = vec![18, 32]; bytes.extend_from_slice(h); Bytes(bytes) } }; ser_seq.serialize_element(&hash)?; let mode = match import.mode { ImportMode::Code => 0, ImportMode::RawText => 1, ImportMode::Location => 2, }; ser_seq.serialize_element(&U64(mode))?; let scheme = match &import.location { ImportLocation::Remote(url) => match url.scheme { Scheme::HTTP => 0, Scheme::HTTPS => 1, }, ImportLocation::Local(prefix, _) => match prefix { FilePrefix::Absolute => 2, FilePrefix::Here => 3, FilePrefix::Parent => 4, FilePrefix::Home => 5, }, ImportLocation::Env(_) => 6, ImportLocation::Missing => 7, }; ser_seq.serialize_element(&U64(scheme))?; match &import.location { ImportLocation::Remote(url) => { match &url.headers { None => ser_seq.serialize_element(&Null)?, Some(e) => { ser_seq.serialize_element(&self::Serialize::Expr(e))? } }; ser_seq.serialize_element(&url.authority)?; for p in &url.path { ser_seq.serialize_element(p)?; } match &url.query { None => ser_seq.serialize_element(&Null)?, Some(x) => ser_seq.serialize_element(x)?, }; } ImportLocation::Local(_, path) => { for p in path { ser_seq.serialize_element(p)?; } } ImportLocation::Env(env) => { ser_seq.serialize_element(env)?; } ImportLocation::Missing => {} } ser_seq.end() } impl<'a, E> serde::ser::Serialize for Serialize<'a, E> { fn serialize(&self, ser: S) -> Result where S: serde::ser::Serializer, { match self { Serialize::Expr(e) => serialize_subexpr(ser, e), Serialize::CBOR(v) => v.serialize(ser), Serialize::RecordMap(map) => { ser.collect_map(map.iter().map(|(k, v)| { (cbor::Value::String(k.into()), Serialize::Expr(v)) })) } Serialize::UnionMap(map) => { ser.collect_map(map.iter().map(|(k, v)| { let v = match v { Some(x) => Serialize::Expr(x), None => Serialize::CBOR(cbor::Value::Null), }; (cbor::Value::String(k.into()), v) })) } } } } fn collect_nested_applications<'a, E>( e: &'a Expr, ) -> (&'a Expr, Vec<&'a Expr>) { fn go<'a, E>(e: &'a Expr, vec: &mut Vec<&'a Expr>) -> &'a Expr { match e.as_ref() { ExprF::App(f, a) => { vec.push(a); go(f, vec) } _ => e, } } let mut vec = vec![]; let e = go(e, &mut vec); (e, vec) } type LetBinding<'a, E> = (&'a Label, &'a Option>, &'a Expr); fn collect_nested_lets<'a, E>( e: &'a Expr, ) -> (&'a Expr, Vec>) { fn go<'a, E>( e: &'a Expr, vec: &mut Vec>, ) -> &'a Expr { match e.as_ref() { ExprF::Let(l, t, v, e) => { vec.push((l, t, v)); go(e, vec) } _ => e, } } let mut vec = vec![]; let e = go(e, &mut vec); (e, vec) }