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// (c) Copyright 2025 Helsing GmbH. All rights reserved.
use super::ValueDelta;
use crate::{
CausalContext, CausalDotStore, DotStore, Identifier, MvReg, OrArray, OrMap,
crdts::{
NoExtensionTypes, Value,
test_util::{ArbitraryDelta, Delta, KeyTracker},
},
};
use quickcheck::{Arbitrary, Gen};
use std::{fmt, ops::RangeBounds};
// NOTE: Box is needed here to allow arbitrary nesting, otherwise the type isn't Sized.
#[cfg_attr(feature = "serde", derive(::serde::Deserialize, ::serde::Serialize))]
#[derive(Debug, Clone)]
pub(crate) enum MapOp {
Apply(usize, Option<String>, Box<ValueDelta>),
Remove(usize),
Clear,
}
impl fmt::Display for MapOp {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Self::Apply(keyi, Some(key), _) => write!(f, "inserts key #{keyi} ({key})"),
Self::Apply(keyi, None, _) => write!(f, "updates key #{keyi}"),
Self::Remove(keyi) => write!(f, "deletes key #{keyi}"),
Self::Clear => write!(f, "clears the map"),
}
}
}
impl Delta for MapOp {
type DS = OrMap<String, NoExtensionTypes>;
fn depends_on_keyi_in<R: RangeBounds<usize>>(&self, range: R) -> bool {
match *self {
Self::Apply(keyi, _, _) | Self::Remove(keyi) => range.contains(&keyi),
Self::Clear => false,
}
}
fn into_crdt(
self,
ds: &Self::DS,
cc: &CausalContext,
id: Identifier,
keys: &mut KeyTracker,
) -> CausalDotStore<Self::DS> {
match self {
Self::Apply(expected_keyi, insert_key, v) => {
let keyi = expected_keyi;
// apply is both insert and update -- figure out which one this is
let should_exist = if let Some(insert_key) = insert_key {
if let Some(&keyi) = keys.map_keys.get_by_left(&insert_key) {
// this means two actors simulteneously inserted with the same key
// that's totally possible! in that case we want to make sure they share
// the same keyi and thus the same KeyTracker so that we accurately track
// inner keys and dependent operations (for shrinking).
assert_eq!(keyi, expected_keyi);
} else {
// this is the actually-first insert of this key, so set up the necessary
// state for tracking inner keys.
let keyi = keys.add_map_key(insert_key);
assert_eq!(keyi, expected_keyi);
}
// NOTE: even for a simultaneous insert, _this_ node should not see the
// key as already existing at the time of this op.
false
} else {
true
};
let inner_keys = &mut keys.inner_keys[keyi];
let key = keys.map_keys.get_by_right(&keyi).unwrap();
ds.apply(
|old, cc, id| {
if should_exist {
assert!(!old.is_bottom());
} else {
assert!(old.is_bottom());
}
match *v {
ValueDelta::Map(m) => m
.into_crdt(&old.map, cc, id, inner_keys)
.map_store(Value::Map),
ValueDelta::Array(a) => a
.into_crdt(&old.array, cc, id, inner_keys)
.map_store(Value::Array),
ValueDelta::Register(r) => r
.into_crdt(&old.reg, cc, id, inner_keys)
.map_store(Value::Register),
}
},
key.clone(),
cc,
id,
)
}
Self::Remove(keyi) => {
let key = keys.map_keys.get_by_right(&keyi).unwrap();
ds.remove(key, cc, id)
}
Self::Clear => ds.clear(cc, id),
}
}
}
impl ArbitraryDelta for OrMap<String, NoExtensionTypes> {
type Delta = MapOp;
fn arbitrary_delta(
&self,
cc: &CausalContext,
id: Identifier,
keys: &mut KeyTracker,
g: &mut Gen,
depth: usize,
) -> (Self::Delta, CausalDotStore<Self>) {
let op = if self.0.is_empty() {
g.choose(&["insert", "clear"])
} else {
g.choose(&["insert", "update", "remove", "clear"])
};
let indent = " ".repeat(depth);
match op.copied().unwrap() {
"insert" => {
let (key, keyi) = {
if self.0.len() != keys.map_keys.len() && bool::arbitrary(g) {
// generate an insert of the same key as another node just inserted (but
// that we haven't observed yet). that is, a simultaneous same-key insert.
let candidates: Vec<_> = keys
.map_keys
.iter()
.filter(|&(k, _)| !self.0.has(k))
.collect();
let (key, keyi) = *g
.choose(&candidates)
.expect("if means we only get here if there's at least one candidate");
(key.clone(), *keyi)
} else {
// generate an insert with a key that not only doesn't exist in this node's
// map, but also isn't used by any _other_ node.
let mut tries = 0;
let key = loop {
let candidate = format!("key{}", u8::arbitrary(g));
if !keys.map_keys.contains_left(&candidate) {
break candidate;
}
tries += 1;
if tries >= 10 {
panic!("could not generate a distinct map key for insert");
}
};
let keyi = keys.add_map_key(key.clone());
(key, keyi)
}
};
eprintln!("{indent} -> insert #{keyi} ({key})");
let inner_keys = &mut keys.inner_keys[keyi];
let key = keys.map_keys.get_by_right(&keyi).unwrap().clone();
let mut value_delta = None;
let crdt = self.apply(
|old, cc, id| {
assert!(old.is_bottom());
let kind = if g.size() <= 1 {
"register"
} else {
g.choose(&["map", "array", "register"]).copied().unwrap()
};
eprintln!("{indent} -> generating inner {kind} operation");
let (vd, value_crdt) = match kind {
"map" => {
let mut g = Gen::new(g.size() / 2);
let g = &mut g;
let (delta, crdt) = OrMap::arbitrary_delta(
&<_>::default(),
cc,
id,
inner_keys,
g,
depth + 1,
);
(ValueDelta::Map(delta), crdt.map_store(Value::Map))
}
"array" => {
let mut g = Gen::new(g.size() / 2);
let g = &mut g;
let (delta, crdt) = OrArray::arbitrary_delta(
&<_>::default(),
cc,
id,
inner_keys,
g,
depth + 1,
);
(ValueDelta::Array(delta), crdt.map_store(Value::Array))
}
"register" => {
let (delta, crdt) = MvReg::arbitrary_delta(
&<_>::default(),
cc,
id,
inner_keys,
g,
depth + 1,
);
(ValueDelta::Register(delta), crdt.map_store(Value::Register))
}
kind => unreachable!("need match arm for '{kind}'"),
};
value_delta = Some(vd);
value_crdt
},
key.clone(),
cc,
id,
);
(
MapOp::Apply(
keyi,
Some(key),
Box::new(value_delta.expect("insert closure is always called")),
),
crdt,
)
}
"update" => {
let mut keyset = self.0.keys();
let keyi = usize::arbitrary(g) % keyset.len();
let key = keyset
.nth(keyi)
.expect("this arm is only taken if non-empty, and n is % len")
.clone();
let keyi = *keys.map_keys.get_by_left(&key).unwrap();
eprintln!("{indent} -> updating #{keyi} ({key})");
let inner_keys = &mut keys.inner_keys[keyi];
// NOTE: this _may_ change the type -- that is intentional! test thoroughly.
let mut value_delta = None;
let crdt = self.apply(
|old, cc, id| {
let kind = if g.size() <= 1 {
"register"
} else {
g.choose(&["map", "array", "register"]).copied().unwrap()
};
eprintln!("{indent} -> generating inner {kind} operation");
let (vd, value_crdt) = match kind {
"map" => {
let mut g = Gen::new(g.size() / 2);
let g = &mut g;
let (delta, crdt) = OrMap::arbitrary_delta(
&old.map,
cc,
id,
inner_keys,
g,
depth + 1,
);
(ValueDelta::Map(delta), crdt.map_store(Value::Map))
}
"array" => {
let mut g = Gen::new(g.size() / 2);
let g = &mut g;
let (delta, crdt) = OrArray::arbitrary_delta(
&old.array,
cc,
id,
inner_keys,
g,
depth + 1,
);
(ValueDelta::Array(delta), crdt.map_store(Value::Array))
}
"register" => {
let (delta, crdt) = MvReg::arbitrary_delta(
&old.reg,
cc,
id,
inner_keys,
g,
depth + 1,
);
(ValueDelta::Register(delta), crdt.map_store(Value::Register))
}
kind => unreachable!("need match arm for '{kind}'"),
};
value_delta = Some(vd);
value_crdt
},
key,
cc,
id,
);
(
MapOp::Apply(
keyi,
None,
Box::new(value_delta.expect("apply closure is always called")),
),
crdt,
)
}
"remove" => {
let mut keyset = self.0.keys();
let keyi = usize::arbitrary(g) % keyset.len();
let key = keyset
.nth(keyi)
.expect("this arm is only taken if non-empty, and n is % len")
.clone();
let keyi = *keys.map_keys.get_by_left(&key).unwrap();
eprintln!("{indent} -> removing #{keyi} ({key})");
(MapOp::Remove(keyi), self.remove(&key, cc, id))
}
"clear" => {
eprintln!("{indent} -> clearing map");
(MapOp::Clear, self.clear(cc, id))
}
op => unreachable!("need match arm for '{op}'"),
}
}
}