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Diffstat (limited to 'src/vm/mod.rs')
| -rw-r--r-- | src/vm/mod.rs | 765 |
1 files changed, 765 insertions, 0 deletions
diff --git a/src/vm/mod.rs b/src/vm/mod.rs new file mode 100644 index 0000000..92a99d7 --- /dev/null +++ b/src/vm/mod.rs @@ -0,0 +1,765 @@ +// Copyright (C) 2021-2022 Soni L. +// SPDX-License-Identifier: MIT OR Apache-2.0 + +//! The Datafu Virtual Machine. +//! +//! This is the stuff that actually matches the pattern. + +use regex::Regex; +use serde::Serialize; + +use crate::Predicate; +//use crate::errors::MatchError; + +mod de; + +pub use de::Unpacker; +pub use de::Packer; + +/// Max depth for VM/serde recursion. +pub(crate) const MAX_CALLS: usize = 250; + +//type Matches<'a, 'b, T> = BTreeMap<&'a str, KVPair<'b, T>>; + +// maybe we should use a builder for this? +/// The constant pool for a pattern. +pub(crate) struct PatternConstants<O: Serialize> { + // last proto is implicitly the whole pattern. + pub(crate) protos: Vec<Vec<PatternElement>>, + // Note that we can borrow these when creating the output map. + // https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=da26f9175e96273fa0b94971a4e6172f + pub(crate) strings: Vec<String>, + pub(crate) regices: Vec<Regex>, + pub(crate) predicates: Vec<Box<Predicate>>, + // NOTE these are part of the constant pool and so have lifetime analogous + // to 'a (consistently used to indicate constant pool lifetime) when used + // elsewhere. In particular, they can't be yielded by the iterator. + pub(crate) defs: Vec<O>, +} + +impl<O: Serialize> Default for PatternConstants<O> { + fn default() -> Self { + Self { + protos: Default::default(), + strings: Default::default(), + regices: Default::default(), + predicates: Default::default(), + defs: Default::default(), + } + } +} + +impl<O: Serialize> std::fmt::Debug for PatternConstants<O> { + fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { + f.debug_struct( + "PatternConstants" + ).field( + "protos", &self.protos, + ).field( + "strings", &self.strings, + ).field( + "regices", &self.regices, + ).field( + "predicates", + &format_args!("({} predicates)", self.predicates.len()), + ).field( + "defs", + &format_args!("FIXME"), + ).finish() + } +} + +/// A pattern element. +#[derive(Copy, Clone, Debug)] +pub(crate) enum PatternElement { + Arrow, + + Identifier(usize), + + StringKey(usize, bool), + RegexKey(usize, bool), + ParameterKey(usize, bool), + KeySubtree(usize, bool), + ValueSubtree(usize, bool), + + /// Represents a predicate which must be applied. + /// + /// These are custom, arbitrary predicates, powered by serde. They're + /// represented by `:$foo` in a pattern. + ApplyPredicate( + /// The predicate index (in `PatternConstants.predicates`). + usize, + /// Whether to skip non-matching values, instead of erroring. + bool, + ), + + /// Represents a type expectation. + /// + /// These are similar to predicates. They're represented by `:foo`, but are + /// built-in and provide functionality not supported by predicates. + /// + /// Specifically, predicates cannot ask serde for a map or a list directly. + /// Instead, they'd be required to parse a whole map/list/etc, which could + /// cause issues which datafu is designed to avoid. (Datafu is designed to + /// resist malicious input more so than arbitrary serde deserializers.) + Type( + /// The expected type. + Type, + /// Whether to skip non-matching values, instead of erroring. + bool, + ), + + End, +} + +/// The types datafu and serde currently support. +/// +/// These are used as expectations for serde (e.g. +/// `Deserializer::deserialize_string`). +#[derive(Copy, Clone, Debug)] +pub(crate) enum Type { + Bool, + I8, + I16, + I32, + I64, + I128, + U8, + U16, + U32, + U64, + U128, + F32, + F64, + Char, + Str, + String, + Bytes, + ByteBuf, + Option, + Unit, + Seq, + Tuple(usize), + Map, + // these aren't really supported: + // UnitStruct, UnitVariant, NewtypeStruct, NewtypeVariant, TupleStruct, + // TupleVariant, Struct, StructVariant + // instead we use type trees for that. + /// Adapter for Type Trees. See `crate::type_tree` for more details. + Of { + /// The type tree index (in `PatternConstants.type_trees`). + type_tree: usize, + }, +} + +pub struct Pack; + +//struct Frame<'a, 'b, T: PatternTypes> { +// //obj: RefOwn<'b, T::Ref, T::Own>, +// ops: &'a [PatternElement], +// iar: Option<usize>, +// depth: usize, +// path: Vec<Holder<'a, 'b, T>>, +// in_key: bool, +//} +// +//impl<'a, 'b, T: PatternTypes> Frame<'a, 'b, T> { +// /// Advances the instruction address register. +// /// +// /// # Returns +// /// +// /// `true` if successful, `false` otherwise. +// fn next(&mut self) -> bool { +// let new = self.iar.map_or(0, |v| v + 1); +// new < self.ops.len() && { +// self.iar = Some(new); +// true +// } +// } +// +// /// Returns the current instruction. +// fn op(&self) -> PatternElement { +// self.ops[self.iar.expect("ops[iar]")] +// } +// +// /// Rewinds the instruction address register. +// /// +// /// # Returns +// /// +// /// `true` if successful, `false` otherwise. +// fn prev(&mut self) -> bool { +// let new = self.iar.expect("iar").checked_sub(1); +// new.is_some() && { +// self.iar = new; +// true +// } +// } +//} +// +///// Stores a single match. +///// +///// See also Holder. +//enum HolderState<'a, 'b, T: PatternTypes> { +// /// Empty holder, for a key-value pair. +// EmptyKey, +// /// Empty holder, for a Matcher and a key-value pair. +// EmptyKeySubtree, +// // /// Empty holder, for a Matcher and a value. +// // EmptyValueSubtree, +// /// Occupied holder, for a key-value pair.. +// Key(KVPair<'b, T>), +// /// Occupied holder, for a Matcher and a key-value pair. +// KeySubtree(Peekable<Matcher<'a, 'b, T>>, KVPair<'b, T>), +// /// Occupied holder, for a Matcher and a value. The empty variant is +// /// omitted as it would never be used otherwise. +// ValueSubtree(Peekable<Matcher<'a, 'b, T>>, RefOwn<'b, T::Ref, T::Own>), +// /// Occupied holder, for a value. The empty variant is omitted as it would +// /// never be used otherwise. +// Value(RefOwn<'b, T::Ref, T::Own>), +//} +// +///// Helper enum for HolderState. +//#[derive(Copy, Clone, Debug, Eq, PartialEq)] +//enum HolderKind { +// Key, +// KeySubtree, +// ValueSubtree, +// Value +//} +// +////impl<'a, 'b, T: PatternTypes> Clone for HolderState<'a, 'b, T> { +//// fn clone(&self) -> Self { +//// match self { +//// HolderState::EmptyKey => HolderState::EmptyKey, +//// HolderState::EmptySubtree => HolderState::EmptySubtree, +//// HolderState::Key(v) => HolderState::Key(*v), +//// HolderState::KeySubtree(m, v) => HolderState::KeySubtree(m.clone(), *v), +//// HolderState::ValueSubtree(m, v) => HolderState::ValueSubtree(m.clone(), *v), +//// HolderState::Value(v) => HolderState::Value(*v), +//// } +//// } +////} +// +//impl<'a, 'b, T: PatternTypes> HolderState<'a, 'b, T> { +// #[rustfmt::skip] +// fn is_empty(&self) -> bool { +// match self { +// | HolderState::EmptyKey +// | HolderState::EmptyKeySubtree +// //| HolderState::EmptyValueSubtree +// => true, _ => false +// } +// } +// +// fn has_value(&self) -> bool { +// !self.is_empty() +// } +// +// fn kind(&self) -> HolderKind { +// match self { +// | HolderState::EmptyKey +// | HolderState::Key(_) +// => HolderKind::Key, +// | HolderState::EmptyKeySubtree +// | HolderState::KeySubtree(_, _) +// => HolderKind::KeySubtree, +// //| HolderState::EmptyValueSubtree +// | HolderState::ValueSubtree(_, _) +// => HolderKind::ValueSubtree, +// | HolderState::Value(_) +// => HolderKind::Value, +// } +// } +// +// fn value(&self) -> Option<RefOwn<'b, T::Ref, T::Own>> { +// match *self { +// HolderState::Key((_, value)) => Some(value), +// HolderState::KeySubtree(_, (_, value)) => Some(value), +// HolderState::ValueSubtree(_, value) => Some(value), +// HolderState::Value(value) => Some(value), +// _ => None +// } +// } +// +// fn key(&self) -> Option<RefOwn<'b, T::Ref, T::Own>> { +// match *self { +// HolderState::Key((key, _)) => Some(key), +// HolderState::KeySubtree(_, (key, _)) => Some(key), +// _ => None +// } +// } +// +// fn pair(&self) -> Option<KVPair<'b, T>> { +// match *self { +// HolderState::Key(pair) => Some(pair), +// HolderState::KeySubtree(_, pair) => Some(pair), +// _ => None +// } +// } +// +// fn subtree(&mut self) -> Option<&mut Peekable<Matcher<'a, 'b, T>>> { +// match *self { +// HolderState::KeySubtree(ref mut subtree, _) => Some(subtree), +// HolderState::ValueSubtree(ref mut subtree, _) => Some(subtree), +// _ => None +// } +// } +// +// fn clear(&mut self) { +// *self = match self.kind() { +// HolderKind::Key => HolderState::EmptyKey, +// HolderKind::KeySubtree => HolderState::EmptyKeySubtree, +// HolderKind::ValueSubtree => unreachable!(), //HolderState::EmptyValueSubtree, +// HolderKind::Value => unreachable!(), +// }; +// assert!(self.is_empty()); +// } +//} +// +///// Stores a single match and associated metadata. +///// +///// A single match is generally a key-value pair, but may be a collection of +///// named pairs in the case of subtree matches, or just a value for the initial +///// holder. +//struct Holder<'a, 'b, T: PatternTypes> { +// name: Option<&'a str>, +// value: HolderState<'a, 'b, T>, +// parent: Option<RefOwn<'b, T::Ref, T::Own>>, +// iterator: Option<Box<dyn Iterator<Item=KVPair<'b, T>> + 'b>>, +// filters: Vec<Box<dyn (for<'c> Fn(&'c mut HolderState<'a, 'b, T>) -> Result<(), MatchError>) + 'a>>, +//} +// +//impl<'a, 'b, T: PatternTypes> Holder<'a, 'b, T> { +// fn next(&mut self) -> Result<bool, MatchError> { +// self.ensure_iterator()?; +// if let Self { +// value: ref mut v, +// iterator: Some(ref mut it), +// ref filters, +// .. +// } = self { +// // check if we're in a subtree and (not) done. +// if let Some(matcher) = v.subtree() { +// if let Some(res) = matcher.peek() { +// // report any errors +// return res.as_ref().map(|_| true).map_err(|e| e.clone()); +// } +// } +// let kind = v.kind(); +// let mut next_v; +// loop { +// next_v = match it.next() { +// Some(pair) => HolderState::Key(pair), +// None => return Ok(false) +// }; +// for filter in filters { +// filter(&mut next_v)?; +// if next_v.is_empty() { +// break; +// } +// } +// if next_v.has_value() { +// break; +// } +// } +// assert!(next_v.has_value()); +// assert_eq!(next_v.kind(), kind); +// *v = next_v; +// Ok(true) +// } else { +// unreachable!() +// } +// } +// +// /// Ensure `self.iterator.is_some()`, creating an iterator if necessary. +// fn ensure_iterator(&mut self) -> Result<(), MatchError> { +// if self.iterator.is_none() { +// let iter = T::pairs(self.parent.unwrap()); +// if iter.is_none() { +// return Err(MatchError::UnsupportedOperation); +// } +// self.iterator = iter; +// } +// assert!(self.iterator.is_some()); +// Ok(()) +// } +//} +// +//impl<'a, 'b, T: PatternTypes> Default for Holder<'a, 'b, T> { +// fn default() -> Self { +// Self { +// name: Default::default(), +// value: HolderState::EmptyKey, +// parent: Default::default(), +// iterator: Default::default(), +// filters: Default::default(), +// } +// } +//} +// +//pub struct Matcher<'a, 'b, T: PatternTypes> { +// defs: &'a PatternConstants<T>, +// frame: Frame<'a, 'b, T>, +//} +// +//// TODO: +//// +//// [x] Arrow +//// [x] StringKey +//// [x] RegexKey +//// [x] KeySubtree +//// [x] ValueSubtree +//// [x] Ident +//// [x] Param (untested) +//// [x] ApplyPredicate +//// [x] End +// +///// Helper for `PatternElement::StringKey`. +//fn on_string_key<'a, 'b, T: PatternTypes>( +// matcher: &mut Matcher<'a, 'b, T>, +// id: usize, +// skippable: bool, +//) -> Result<bool, MatchError> { +// let path = matcher.frame.path.last_mut().unwrap(); +// assert!(path.iterator.is_none()); +// let key = &matcher.defs.strings[id]; +// let iter = T::get(path.parent.unwrap(), RefOwn::Str(key)); +// match iter { +// Some(None) if !skippable => Err(MatchError::ValidationError), +// Some(opt) => { +// path.iterator = Some(Box::new(opt.into_iter())); +// Ok(true) +// } +// None => Err(MatchError::UnsupportedOperation), +// } +//} +// +///// Helper for `PatternElement::ParameterKey`. +//fn on_parameter_key<'a, 'b, T: PatternTypes>( +// matcher: &mut Matcher<'a, 'b, T>, +// id: usize, +// skippable: bool, +//) -> Result<bool, MatchError> { +// let path = matcher.frame.path.last_mut().unwrap(); +// assert!(path.iterator.is_none()); +// let key = matcher.defs.defs[id]; +// let iter = T::get(path.parent.unwrap(), RefOwn::Own(key)); +// match iter { +// Some(None) if !skippable => Err(MatchError::ValidationError), +// Some(opt) => { +// path.iterator = Some(Box::new(opt.into_iter())); +// Ok(true) +// } +// None => Err(MatchError::UnsupportedOperation), +// } +//} +// +///// Helper for `PatternElement::RegexKey`. +//fn on_regex_key<'a, 'b, T: PatternTypes>( +// matcher: &mut Matcher<'a, 'b, T>, +// id: usize, +// skippable: bool, +//) -> Result<bool, MatchError> { +// matcher.frame.path.last_mut().unwrap().ensure_iterator()?; +// let re = &matcher.defs.regices[id]; +// let path = matcher.frame.path.last_mut().unwrap(); +// path.filters.push(Box::new(move |value| { +// let s = T::as_str(value.key().unwrap()); +// match (s.map_or(false, |s| re.is_match(s)), skippable) { +// (true, _) => Ok(()), +// (false, true) => { +// value.clear(); +// Ok(()) +// }, +// (false, false) => Err(MatchError::ValidationError), +// } +// })); +// Ok(true) +//} +// +///// Helper for `PatternElement::KeySubtree`. +//fn on_key_subtree<'a, 'b, T: PatternTypes>( +// matcher: &mut Matcher<'a, 'b, T>, +// id: usize, +// skippable: bool, +//) -> Result<bool, MatchError> { +// let _ = skippable; // FIXME what should a skippable KeySubtree even do?! +// matcher.frame.path.last_mut().unwrap().ensure_iterator()?; +// let defs = matcher.defs; +// let rlimit: usize = matcher.frame.depth; +// let path = matcher.frame.path.last_mut().unwrap(); +// assert!(path.value.is_empty()); +// assert_eq!(path.value.kind(), HolderKind::Key); +// path.value = HolderState::EmptyKeySubtree; +// path.filters.push(Box::new(move |value| { +// let key = value.key().unwrap(); +// let mut subtree = Matcher::new(key, defs, id, rlimit)?.peekable(); +// match subtree.peek() { +// Some(&Ok(_)) => { +// *value = HolderState::KeySubtree(subtree, value.pair().unwrap()); +// Ok(()) +// }, +// Some(&Err(ref e)) => { +// Err(e.clone()) +// }, +// None => { +// value.clear(); +// Ok(()) +// } +// } +// })); +// Ok(true) +//} +// +//const DUMMY_OPS: &'static [PatternElement] = &[]; +// +//impl<'a, 'b, T: PatternTypes> Matcher<'a, 'b, T> { +// pub(crate) fn new(obj: RefOwn<'b, T::Ref, T::Own>, defs: &'a PatternConstants<T>, proto: usize, rlimit: usize) -> Result<Self, MatchError> { +// let ops: &[_] = &defs.protos[proto]; +// Self::with_ops(obj, defs, ops, rlimit) +// } +// +// /// Constructs a Matcher that yields a single dummy result. +// fn with_ops(obj: RefOwn<'b, T::Ref, T::Own>, defs: &'a PatternConstants<T>, ops: &'a [PatternElement], rlimit: usize) -> Result<Self, MatchError> { +// let depth = rlimit.checked_sub(1).ok_or(MatchError::StackOverflow)?; +// Ok(Self { +// defs: defs, +// frame: Frame { +// //obj: obj, +// ops: ops, +// iar: None, +// depth: depth, +// path: { +// let mut holder = Holder::default(); +// holder.value = HolderState::Value(obj); +// holder.iterator = Some(Box::new(std::iter::empty())); +// vec![holder] +// }, +// in_key: false, +// }, +// }) +// } +// +// fn on_in_key(&mut self) -> Result<bool, MatchError> { +// match self.frame.op() { +// PatternElement::End => { +// let path = self.frame.path.last_mut().unwrap(); +// if path.next()? { +// Ok(false) +// } else { +// drop(path); +// self.frame.path.pop().unwrap(); +// // stop at previous End, or start of frame +// while self.frame.prev() { +// if matches!(self.frame.op(), PatternElement::End) { +// break; +// } +// } +// // is start of frame? +// if !self.frame.prev() { +// self.frame.path.clear(); +// } +// Ok(true) +// } +// }, +// PatternElement::ApplyPredicate(id, skippable) => { +// // failing on T::get() is already handled, but we may need a +// // T::pairs(). construct it here. +// self.frame.path.last_mut().unwrap().ensure_iterator()?; +// let pred = &self.defs.predicates[id]; +// let path = self.frame.path.last_mut().unwrap(); +// path.filters.push(Box::new(move |value| { +// match (pred(value.value().unwrap()), skippable) { +// (true, _) => Ok(()), +// (false, true) => { +// value.clear(); +// Ok(()) +// }, +// (false, false) => Err(MatchError::ValidationError), +// } +// })); +// Ok(true) +// }, +// PatternElement::StringKey(id, skippable) => { +// on_string_key(self, id, skippable) +// }, +// PatternElement::ParameterKey(id, skippable) => { +// on_parameter_key(self, id, skippable) +// }, +// PatternElement::RegexKey(id, skippable) => { +// on_regex_key(self, id, skippable) +// }, +// PatternElement::KeySubtree(id, skippable) => { +// on_key_subtree(self, id, skippable) +// }, +// _ => unreachable!("on_in_key") +// } +// } +// +// fn on_not_in_key(&mut self) -> Result<bool, MatchError> { +// match self.frame.op() { +// PatternElement::Arrow => { +// // this *should* always pass. +// assert!(self.frame.path.last().unwrap().iterator.is_some()); +// let mut holder = Holder::default(); +// holder.parent = self.frame.path.last().unwrap().value.value(); +// assert!(holder.parent.is_some()); +// self.frame.path.push(holder); +// Ok(false) +// }, +// PatternElement::Identifier(id) => { +// let name = self.defs.strings.get(id).map(|s| &**s); +// let path = self.frame.path.last_mut().unwrap(); +// path.name = name; +// assert!(path.iterator.is_none()); +// // we don't actually create the iterator here, +// // as we may still wanna use T::get() instead. +// Ok(true) +// }, +// PatternElement::ApplyPredicate(id, skippable) => { +// assert!(self.frame.path.len() == 1); +// let pred = &self.defs.predicates[id]; +// let value = self.frame.path.last().unwrap().value.value(); +// match (pred(value.unwrap()), skippable) { +// (true, _) => Ok(false), +// (false, true) => { +// self.frame.path.clear(); +// // any Ok(_) will do +// Ok(false) +// }, +// (false, false) => Err(MatchError::ValidationError), +// } +// }, +// PatternElement::StringKey(id, skippable) => { +// on_string_key(self, id, skippable) +// }, +// PatternElement::ParameterKey(id, skippable) => { +// on_parameter_key(self, id, skippable) +// }, +// PatternElement::RegexKey(id, skippable) => { +// on_regex_key(self, id, skippable) +// }, +// PatternElement::KeySubtree(id, skippable) => { +// on_key_subtree(self, id, skippable) +// }, +// PatternElement::ValueSubtree(id, skippable) => { +// let value = self.frame.path.last().unwrap().value.value().unwrap(); +// let mut subtree = Matcher::new( +// value, +// self.defs, +// id, +// self.frame.depth +// )?.peekable(); +// let mut dummy = Matcher::with_ops( +// value, +// self.defs, +// DUMMY_OPS, +// self.frame.depth +// )?.peekable(); +// // may panic. +// let peeked = subtree.peek(); +// // shouldn't panic. +// let _ = dummy.peek(); +// // push Holder after peek. +// self.frame.path.push(Holder::default()); +// let mut holder = self.frame.path.last_mut().unwrap(); +// holder.parent = Some(value); +// holder.iterator = Some(Box::new(std::iter::empty())); +// match peeked { +// None if skippable => { +// holder.value = HolderState::ValueSubtree(dummy, value); +// Ok(true) +// }, +// Some(&Ok(_)) | None => { +// drop(peeked); +// holder.value = HolderState::ValueSubtree(subtree, value); +// Ok(true) +// }, +// Some(&Err(ref e)) => { +// Err(e.clone()) +// }, +// } +// }, +// _ => unreachable!("on_not_in_key") +// } +// } +// +// fn collect_results(&mut self) -> Matches<'a, 'b, T> { +// let mut res: Matches<'a, 'b, T> = Default::default(); +// for holder in &mut self.frame.path { +// // make sure it's not empty. +// assert!(holder.value.has_value()); +// // handle subtrees. +// if let Some(matcher) = holder.value.subtree() { +// if let Some(matches) = matcher.next() { +// // NOTE: we have checked these already. +// // (and if we haven't, that's a bug.) +// res.extend(matches.unwrap()); +// } +// } +// // handle pairs. +// if let Some(pair) = holder.value.pair() { +// if let Some(name) = holder.name { +// res.insert(name, pair); +// } +// } +// } +// res +// } +// +// fn on_end(&mut self) -> (bool, Matches<'a, 'b, T>) { +// match self.frame.op() { +// PatternElement::End => { +// assert!(!self.frame.path.last().expect("path").value.is_empty()); +// let res = self.collect_results(); +// if !self.frame.prev() { +// // NOTE: frame.prev() must always be called, even if this +// // gets replaced with debug_assert!() in the future. +// assert!(false, "frame.prev()"); +// } +// (true, res) +// } +// PatternElement::ApplyPredicate {..} => { +// assert!(!self.frame.in_key); +// let res = self.collect_results(); +// self.frame.path.clear(); +// (false, res) +// } +// _ => unreachable!("on_end") +// } +// } +//} +// +//impl<'a, 'b, T: PatternTypes> Iterator for Matcher<'a, 'b, T> { +// type Item = Result<BTreeMap<&'a str, KVPair<'b, T>>, MatchError>; +// +// fn next(&mut self) -> Option<Self::Item> { +// if self.frame.ops.is_empty() { +// if !self.frame.path.is_empty() { +// self.frame.path.clear(); +// return Some(Ok(Default::default())); +// } +// } +// while !self.frame.path.is_empty() { +// if !self.frame.next() { +// let (in_key, res) = self.on_end(); +// self.frame.in_key = in_key; +// return Some(Ok(res)); +// } else { +// let in_key = if self.frame.in_key { +// self.on_in_key() +// } else { +// self.on_not_in_key() +// }; +// match in_key { +// Ok(in_key) => self.frame.in_key = in_key, +// Err(e) => { +// self.frame.path.clear(); +// return Some(Err(e)) +// }, +// } +// } +// } +// None +// } +//} |