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-rw-r--r-- | src/test/ui/drop/dropck_legal_cycles.rs | 1183 |
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diff --git a/src/test/ui/drop/dropck_legal_cycles.rs b/src/test/ui/drop/dropck_legal_cycles.rs new file mode 100644 index 000000000..27a599315 --- /dev/null +++ b/src/test/ui/drop/dropck_legal_cycles.rs @@ -0,0 +1,1183 @@ +// run-pass +// This test exercises cases where cyclic structure is legal, +// including when the cycles go through data-structures such +// as `Vec` or `TypedArena`. +// +// The intent is to cover as many such cases as possible, ensuring +// that if the compiler did not complain circa Rust 1.x (1.2 as of +// this writing), then it will continue to not complain in the future. +// +// Note that while some of the tests are only exercising using the +// given collection as a "backing store" for a set of nodes that hold +// the actual cycle (and thus the cycle does not go through the +// collection itself in such cases), in general we *do* want to make +// sure to have at least one example exercising a cycle that goes +// through the collection, for every collection type that supports +// this. + +// HIGH LEVEL DESCRIPTION OF THE TEST ARCHITECTURE +// ----------------------------------------------- +// +// We pick a data structure and want to make a cyclic construction +// from it. Each test of interest is labelled starting with "Cycle N: +// { ... }" where N is the test number and the "..."`is filled in with +// a graphviz-style description of the graph structure that the +// author believes is being made. So "{ a -> b, b -> (c,d), (c,d) -> e }" +// describes a line connected to a diamond: +// +// c +// / \ +// a - b e +// \ / +// d +// +// (Note that the above directed graph is actually acyclic.) +// +// The different graph structures are often composed of different data +// types. Some may be built atop `Vec`, others atop `HashMap`, etc. +// +// For each graph structure, we actually *confirm* that a cycle exists +// (as a safe-guard against a test author accidentally leaving it out) +// by traversing each graph and "proving" that a cycle exists within it. +// +// To do this, while trying to keep the code uniform (despite working +// with different underlying collection and smart-pointer types), we +// have a standard traversal API: +// +// 1. every node in the graph carries a `mark` (a u32, init'ed to 0). +// +// 2. every node provides a method to visit its children +// +// 3. a traversal attmepts to visit the nodes of the graph and prove that +// it sees the same node twice. It does this by setting the mark of each +// node to a fresh non-zero value, and if it sees the current mark, it +// "knows" that it must have found a cycle, and stops attempting further +// traversal. +// +// 4. each traversal is controlled by a bit-string that tells it which child +// it visit when it can take different paths. As a simple example, +// in a binary tree, 0 could mean "left" (and 1, "right"), so that +// "00010" means "left, left, left, right, left". (In general it will +// read as many bits as it needs to choose one child.) +// +// The graphs in this test are all meant to be very small, and thus +// short bitstrings of less than 64 bits should always suffice. +// +// (An earlier version of this test infrastructure simply had any +// given traversal visit all children it encountered, in a +// depth-first manner; one problem with this approach is that an +// acyclic graph can still have sharing, which would then be treated +// as a repeat mark and reported as a detected cycle.) +// +// The travseral code is a little more complicated because it has been +// programmed in a somewhat defensive manner. For example it also has +// a max threshold for the number of nodes it will visit, to guard +// against scenarios where the nodes are not correctly setting their +// mark when asked. There are various other methods not discussed here +// that are for aiding debugging the test when it runs, such as the +// `name` method that all nodes provide. +// +// So each test: +// +// 1. allocates the nodes in the graph, +// +// 2. sets up the links in the graph, +// +// 3. clones the "ContextData" +// +// 4. chooses a new current mark value for this test +// +// 5. initiates a traversal, potentially from multiple starting points +// (aka "roots"), with a given control-string (potentially a +// different string for each root). if it does start from a +// distinct root, then such a test should also increment the +// current mark value, so that this traversal is considered +// distinct from the prior one on this graph structure. +// +// Note that most of the tests work with the default control string +// of all-zeroes. +// +// 6. assert that the context confirms that it actually saw a cycle (since a traversal +// might have terminated, e.g., on a tree structure that contained no cycles). + +use std::cell::{Cell, RefCell}; +use std::cmp::Ordering; +use std::collections::BinaryHeap; +use std::collections::HashMap; +use std::collections::LinkedList; +use std::collections::VecDeque; +use std::collections::btree_map::BTreeMap; +use std::collections::btree_set::BTreeSet; +use std::hash::{Hash, Hasher}; +use std::rc::Rc; +use std::sync::{Arc, RwLock, Mutex}; + +const PRINT: bool = false; + +pub fn main() { + let c_orig = ContextData { + curr_depth: 0, + max_depth: 3, + visited: 0, + max_visits: 1000, + skipped: 0, + curr_mark: 0, + saw_prev_marked: false, + control_bits: 0, + }; + + // SANITY CHECK FOR TEST SUITE (thus unnumbered) + // Not a cycle: { v[0] -> (v[1], v[2]), v[1] -> v[3], v[2] -> v[3] }; + let v: Vec<S2> = vec![Named::new("s0"), + Named::new("s1"), + Named::new("s2"), + Named::new("s3")]; + v[0].next.set((Some(&v[1]), Some(&v[2]))); + v[1].next.set((Some(&v[3]), None)); + v[2].next.set((Some(&v[3]), None)); + v[3].next.set((None, None)); + + let mut c = c_orig.clone(); + c.curr_mark = 10; + assert!(!c.saw_prev_marked); + v[0].descend_into_self(&mut c); + assert!(!c.saw_prev_marked); // <-- different from below, b/c acyclic above + + if PRINT { println!(); } + + // Cycle 1: { v[0] -> v[1], v[1] -> v[0] }; + // does not exercise `v` itself + let v: Vec<S> = vec![Named::new("s0"), + Named::new("s1")]; + v[0].next.set(Some(&v[1])); + v[1].next.set(Some(&v[0])); + + let mut c = c_orig.clone(); + c.curr_mark = 10; + assert!(!c.saw_prev_marked); + v[0].descend_into_self(&mut c); + assert!(c.saw_prev_marked); + + if PRINT { println!(); } + + // Cycle 2: { v[0] -> v, v[1] -> v } + let v: V = Named::new("v"); + v.contents[0].set(Some(&v)); + v.contents[1].set(Some(&v)); + + let mut c = c_orig.clone(); + c.curr_mark = 20; + assert!(!c.saw_prev_marked); + v.descend_into_self(&mut c); + assert!(c.saw_prev_marked); + + if PRINT { println!(); } + + // Cycle 3: { hk0 -> hv0, hv0 -> hk0, hk1 -> hv1, hv1 -> hk1 }; + // does not exercise `h` itself + + let mut h: HashMap<H,H> = HashMap::new(); + h.insert(Named::new("hk0"), Named::new("hv0")); + h.insert(Named::new("hk1"), Named::new("hv1")); + for (key, val) in h.iter() { + val.next.set(Some(key)); + key.next.set(Some(val)); + } + + let mut c = c_orig.clone(); + c.curr_mark = 30; + for (key, _) in h.iter() { + c.curr_mark += 1; + c.saw_prev_marked = false; + key.descend_into_self(&mut c); + assert!(c.saw_prev_marked); + } + + if PRINT { println!(); } + + // Cycle 4: { h -> (hmk0,hmv0,hmk1,hmv1), {hmk0,hmv0,hmk1,hmv1} -> h } + + let mut h: HashMap<HM,HM> = HashMap::new(); + h.insert(Named::new("hmk0"), Named::new("hmv0")); + h.insert(Named::new("hmk0"), Named::new("hmv0")); + for (key, val) in h.iter() { + val.contents.set(Some(&h)); + key.contents.set(Some(&h)); + } + + let mut c = c_orig.clone(); + c.max_depth = 2; + c.curr_mark = 40; + for (key, _) in h.iter() { + c.curr_mark += 1; + c.saw_prev_marked = false; + key.descend_into_self(&mut c); + assert!(c.saw_prev_marked); + // break; + } + + if PRINT { println!(); } + + // Cycle 5: { vd[0] -> vd[1], vd[1] -> vd[0] }; + // does not exercise vd itself + let mut vd: VecDeque<S> = VecDeque::new(); + vd.push_back(Named::new("d0")); + vd.push_back(Named::new("d1")); + vd[0].next.set(Some(&vd[1])); + vd[1].next.set(Some(&vd[0])); + + let mut c = c_orig.clone(); + c.curr_mark = 50; + assert!(!c.saw_prev_marked); + vd[0].descend_into_self(&mut c); + assert!(c.saw_prev_marked); + + if PRINT { println!(); } + + // Cycle 6: { vd -> (vd0, vd1), {vd0, vd1} -> vd } + let mut vd: VecDeque<VD> = VecDeque::new(); + vd.push_back(Named::new("vd0")); + vd.push_back(Named::new("vd1")); + vd[0].contents.set(Some(&vd)); + vd[1].contents.set(Some(&vd)); + + let mut c = c_orig.clone(); + c.curr_mark = 60; + assert!(!c.saw_prev_marked); + vd[0].descend_into_self(&mut c); + assert!(c.saw_prev_marked); + + if PRINT { println!(); } + + // Cycle 7: { vm -> (vm0, vm1), {vm0, vm1} -> vm } + let mut vm: HashMap<usize, VM> = HashMap::new(); + vm.insert(0, Named::new("vm0")); + vm.insert(1, Named::new("vm1")); + vm[&0].contents.set(Some(&vm)); + vm[&1].contents.set(Some(&vm)); + + let mut c = c_orig.clone(); + c.curr_mark = 70; + assert!(!c.saw_prev_marked); + vm[&0].descend_into_self(&mut c); + assert!(c.saw_prev_marked); + + if PRINT { println!(); } + + // Cycle 8: { ll -> (ll0, ll1), {ll0, ll1} -> ll } + let mut ll: LinkedList<LL> = LinkedList::new(); + ll.push_back(Named::new("ll0")); + ll.push_back(Named::new("ll1")); + for e in &ll { + e.contents.set(Some(&ll)); + } + + let mut c = c_orig.clone(); + c.curr_mark = 80; + for e in &ll { + c.curr_mark += 1; + c.saw_prev_marked = false; + e.descend_into_self(&mut c); + assert!(c.saw_prev_marked); + // break; + } + + if PRINT { println!(); } + + // Cycle 9: { bh -> (bh0, bh1), {bh0, bh1} -> bh } + let mut bh: BinaryHeap<BH> = BinaryHeap::new(); + bh.push(Named::new("bh0")); + bh.push(Named::new("bh1")); + for b in bh.iter() { + b.contents.set(Some(&bh)); + } + + let mut c = c_orig.clone(); + c.curr_mark = 90; + for b in &bh { + c.curr_mark += 1; + c.saw_prev_marked = false; + b.descend_into_self(&mut c); + assert!(c.saw_prev_marked); + // break; + } + + if PRINT { println!(); } + + // Cycle 10: { btm -> (btk0, btv1), {bt0, bt1} -> btm } + let mut btm: BTreeMap<BTM, BTM> = BTreeMap::new(); + btm.insert(Named::new("btk0"), Named::new("btv0")); + btm.insert(Named::new("btk1"), Named::new("btv1")); + for (k, v) in btm.iter() { + k.contents.set(Some(&btm)); + v.contents.set(Some(&btm)); + } + + let mut c = c_orig.clone(); + c.curr_mark = 100; + for (k, _) in &btm { + c.curr_mark += 1; + c.saw_prev_marked = false; + k.descend_into_self(&mut c); + assert!(c.saw_prev_marked); + // break; + } + + if PRINT { println!(); } + + // Cycle 10: { bts -> (bts0, bts1), {bts0, bts1} -> btm } + let mut bts: BTreeSet<BTS> = BTreeSet::new(); + bts.insert(Named::new("bts0")); + bts.insert(Named::new("bts1")); + for v in bts.iter() { + v.contents.set(Some(&bts)); + } + + let mut c = c_orig.clone(); + c.curr_mark = 100; + for b in &bts { + c.curr_mark += 1; + c.saw_prev_marked = false; + b.descend_into_self(&mut c); + assert!(c.saw_prev_marked); + // break; + } + + if PRINT { println!(); } + + // Cycle 11: { rc0 -> (rc1, rc2), rc1 -> (), rc2 -> rc0 } + let (rc0, rc1, rc2): (RCRC, RCRC, RCRC); + rc0 = RCRC::new("rcrc0"); + rc1 = RCRC::new("rcrc1"); + rc2 = RCRC::new("rcrc2"); + rc0.0.borrow_mut().children.0 = Some(&rc1); + rc0.0.borrow_mut().children.1 = Some(&rc2); + rc2.0.borrow_mut().children.0 = Some(&rc0); + + let mut c = c_orig.clone(); + c.control_bits = 0b1; + c.curr_mark = 110; + assert!(!c.saw_prev_marked); + rc0.descend_into_self(&mut c); + assert!(c.saw_prev_marked); + + if PRINT { println!(); } + + // We want to take the previous Rc case and generalize it to Arc. + // + // We can use refcells if we're single-threaded (as this test is). + // If one were to generalize these constructions to a + // multi-threaded context, then it might seem like we could choose + // between either an RwLock or a Mutex to hold the owned arcs on + // each node. + // + // Part of the point of this test is to actually confirm that the + // cycle exists by traversing it. We can do that just fine with an + // RwLock (since we can grab the child pointers in read-only + // mode), but we cannot lock a std::sync::Mutex to guard reading + // from each node via the same pattern, since once you hit the + // cycle, you'll be trying to acquiring the same lock twice. + // (We deal with this by exiting the traversal early if try_lock fails.) + + // Cycle 12: { arc0 -> (arc1, arc2), arc1 -> (), arc2 -> arc0 }, refcells + let (arc0, arc1, arc2): (ARCRC, ARCRC, ARCRC); + arc0 = ARCRC::new("arcrc0"); + arc1 = ARCRC::new("arcrc1"); + arc2 = ARCRC::new("arcrc2"); + arc0.0.borrow_mut().children.0 = Some(&arc1); + arc0.0.borrow_mut().children.1 = Some(&arc2); + arc2.0.borrow_mut().children.0 = Some(&arc0); + + let mut c = c_orig.clone(); + c.control_bits = 0b1; + c.curr_mark = 110; + assert!(!c.saw_prev_marked); + arc0.descend_into_self(&mut c); + assert!(c.saw_prev_marked); + + if PRINT { println!(); } + + // Cycle 13: { arc0 -> (arc1, arc2), arc1 -> (), arc2 -> arc0 }, rwlocks + let (arc0, arc1, arc2): (ARCRW, ARCRW, ARCRW); + arc0 = ARCRW::new("arcrw0"); + arc1 = ARCRW::new("arcrw1"); + arc2 = ARCRW::new("arcrw2"); + arc0.0.write().unwrap().children.0 = Some(&arc1); + arc0.0.write().unwrap().children.1 = Some(&arc2); + arc2.0.write().unwrap().children.0 = Some(&arc0); + + let mut c = c_orig.clone(); + c.control_bits = 0b1; + c.curr_mark = 110; + assert!(!c.saw_prev_marked); + arc0.descend_into_self(&mut c); + assert!(c.saw_prev_marked); + + if PRINT { println!(); } + + // Cycle 14: { arc0 -> (arc1, arc2), arc1 -> (), arc2 -> arc0 }, mutexs + let (arc0, arc1, arc2): (ARCM, ARCM, ARCM); + arc0 = ARCM::new("arcm0"); + arc1 = ARCM::new("arcm1"); + arc2 = ARCM::new("arcm2"); + arc0.1.lock().unwrap().children.0 = Some(&arc1); + arc0.1.lock().unwrap().children.1 = Some(&arc2); + arc2.1.lock().unwrap().children.0 = Some(&arc0); + + let mut c = c_orig.clone(); + c.control_bits = 0b1; + c.curr_mark = 110; + assert!(!c.saw_prev_marked); + arc0.descend_into_self(&mut c); + assert!(c.saw_prev_marked); +} + +trait Named { + fn new(_: &'static str) -> Self; + fn name(&self) -> &str; +} + +trait Marked<M> { + fn mark(&self) -> M; + fn set_mark(&self, mark: M); +} + +struct S<'a> { + name: &'static str, + mark: Cell<u32>, + next: Cell<Option<&'a S<'a>>>, +} + +impl<'a> Named for S<'a> { + fn new(name: &'static str) -> S<'a> { + S { name: name, mark: Cell::new(0), next: Cell::new(None) } + } + fn name(&self) -> &str { self.name } +} + +impl<'a> Marked<u32> for S<'a> { + fn mark(&self) -> u32 { self.mark.get() } + fn set_mark(&self, mark: u32) { self.mark.set(mark); } +} + +struct S2<'a> { + name: &'static str, + mark: Cell<u32>, + next: Cell<(Option<&'a S2<'a>>, Option<&'a S2<'a>>)>, +} + +impl<'a> Named for S2<'a> { + fn new(name: &'static str) -> S2<'a> { + S2 { name: name, mark: Cell::new(0), next: Cell::new((None, None)) } + } + fn name(&self) -> &str { self.name } +} + +impl<'a> Marked<u32> for S2<'a> { + fn mark(&self) -> u32 { self.mark.get() } + fn set_mark(&self, mark: u32) { + self.mark.set(mark); + } +} + +struct V<'a> { + name: &'static str, + mark: Cell<u32>, + contents: Vec<Cell<Option<&'a V<'a>>>>, +} + +impl<'a> Named for V<'a> { + fn new(name: &'static str) -> V<'a> { + V { name: name, + mark: Cell::new(0), + contents: vec![Cell::new(None), Cell::new(None)] + } + } + fn name(&self) -> &str { self.name } +} + +impl<'a> Marked<u32> for V<'a> { + fn mark(&self) -> u32 { self.mark.get() } + fn set_mark(&self, mark: u32) { self.mark.set(mark); } +} + +#[derive(Eq)] +struct H<'a> { + name: &'static str, + mark: Cell<u32>, + next: Cell<Option<&'a H<'a>>>, +} + +impl<'a> Named for H<'a> { + fn new(name: &'static str) -> H<'a> { + H { name: name, mark: Cell::new(0), next: Cell::new(None) } + } + fn name(&self) -> &str { self.name } +} + +impl<'a> Marked<u32> for H<'a> { + fn mark(&self) -> u32 { self.mark.get() } + fn set_mark(&self, mark: u32) { self.mark.set(mark); } +} + +impl<'a> PartialEq for H<'a> { + fn eq(&self, rhs: &H<'a>) -> bool { + self.name == rhs.name + } +} + +impl<'a> Hash for H<'a> { + fn hash<H: Hasher>(&self, state: &mut H) { + self.name.hash(state) + } +} + +#[derive(Eq)] +struct HM<'a> { + name: &'static str, + mark: Cell<u32>, + contents: Cell<Option<&'a HashMap<HM<'a>, HM<'a>>>>, +} + +impl<'a> Named for HM<'a> { + fn new(name: &'static str) -> HM<'a> { + HM { name: name, + mark: Cell::new(0), + contents: Cell::new(None) + } + } + fn name(&self) -> &str { self.name } +} + +impl<'a> Marked<u32> for HM<'a> { + fn mark(&self) -> u32 { self.mark.get() } + fn set_mark(&self, mark: u32) { self.mark.set(mark); } +} + +impl<'a> PartialEq for HM<'a> { + fn eq(&self, rhs: &HM<'a>) -> bool { + self.name == rhs.name + } +} + +impl<'a> Hash for HM<'a> { + fn hash<H: Hasher>(&self, state: &mut H) { + self.name.hash(state) + } +} + + +struct VD<'a> { + name: &'static str, + mark: Cell<u32>, + contents: Cell<Option<&'a VecDeque<VD<'a>>>>, +} + +impl<'a> Named for VD<'a> { + fn new(name: &'static str) -> VD<'a> { + VD { name: name, + mark: Cell::new(0), + contents: Cell::new(None) + } + } + fn name(&self) -> &str { self.name } +} + +impl<'a> Marked<u32> for VD<'a> { + fn mark(&self) -> u32 { self.mark.get() } + fn set_mark(&self, mark: u32) { self.mark.set(mark); } +} + +struct VM<'a> { + name: &'static str, + mark: Cell<u32>, + contents: Cell<Option<&'a HashMap<usize, VM<'a>>>>, +} + +impl<'a> Named for VM<'a> { + fn new(name: &'static str) -> VM<'a> { + VM { name: name, + mark: Cell::new(0), + contents: Cell::new(None) + } + } + fn name(&self) -> &str { self.name } +} + +impl<'a> Marked<u32> for VM<'a> { + fn mark(&self) -> u32 { self.mark.get() } + fn set_mark(&self, mark: u32) { self.mark.set(mark); } +} + +struct LL<'a> { + name: &'static str, + mark: Cell<u32>, + contents: Cell<Option<&'a LinkedList<LL<'a>>>>, +} + +impl<'a> Named for LL<'a> { + fn new(name: &'static str) -> LL<'a> { + LL { name: name, + mark: Cell::new(0), + contents: Cell::new(None) + } + } + fn name(&self) -> &str { self.name } +} + +impl<'a> Marked<u32> for LL<'a> { + fn mark(&self) -> u32 { self.mark.get() } + fn set_mark(&self, mark: u32) { self.mark.set(mark); } +} + +struct BH<'a> { + name: &'static str, + mark: Cell<u32>, + contents: Cell<Option<&'a BinaryHeap<BH<'a>>>>, +} + +impl<'a> Named for BH<'a> { + fn new(name: &'static str) -> BH<'a> { + BH { name: name, + mark: Cell::new(0), + contents: Cell::new(None) + } + } + fn name(&self) -> &str { self.name } +} + +impl<'a> Marked<u32> for BH<'a> { + fn mark(&self) -> u32 { self.mark.get() } + fn set_mark(&self, mark: u32) { self.mark.set(mark); } +} + +impl<'a> Eq for BH<'a> { } + +impl<'a> PartialEq for BH<'a> { + fn eq(&self, rhs: &BH<'a>) -> bool { + self.name == rhs.name + } +} + +impl<'a> PartialOrd for BH<'a> { + fn partial_cmp(&self, rhs: &BH<'a>) -> Option<Ordering> { + Some(self.cmp(rhs)) + } +} + +impl<'a> Ord for BH<'a> { + fn cmp(&self, rhs: &BH<'a>) -> Ordering { + self.name.cmp(rhs.name) + } +} + +struct BTM<'a> { + name: &'static str, + mark: Cell<u32>, + contents: Cell<Option<&'a BTreeMap<BTM<'a>, BTM<'a>>>>, +} + +impl<'a> Named for BTM<'a> { + fn new(name: &'static str) -> BTM<'a> { + BTM { name: name, + mark: Cell::new(0), + contents: Cell::new(None) + } + } + fn name(&self) -> &str { self.name } +} + +impl<'a> Marked<u32> for BTM<'a> { + fn mark(&self) -> u32 { self.mark.get() } + fn set_mark(&self, mark: u32) { self.mark.set(mark); } +} + +impl<'a> Eq for BTM<'a> { } + +impl<'a> PartialEq for BTM<'a> { + fn eq(&self, rhs: &BTM<'a>) -> bool { + self.name == rhs.name + } +} + +impl<'a> PartialOrd for BTM<'a> { + fn partial_cmp(&self, rhs: &BTM<'a>) -> Option<Ordering> { + Some(self.cmp(rhs)) + } +} + +impl<'a> Ord for BTM<'a> { + fn cmp(&self, rhs: &BTM<'a>) -> Ordering { + self.name.cmp(rhs.name) + } +} + +struct BTS<'a> { + name: &'static str, + mark: Cell<u32>, + contents: Cell<Option<&'a BTreeSet<BTS<'a>>>>, +} + +impl<'a> Named for BTS<'a> { + fn new(name: &'static str) -> BTS<'a> { + BTS { name: name, + mark: Cell::new(0), + contents: Cell::new(None) + } + } + fn name(&self) -> &str { self.name } +} + +impl<'a> Marked<u32> for BTS<'a> { + fn mark(&self) -> u32 { self.mark.get() } + fn set_mark(&self, mark: u32) { self.mark.set(mark); } +} + +impl<'a> Eq for BTS<'a> { } + +impl<'a> PartialEq for BTS<'a> { + fn eq(&self, rhs: &BTS<'a>) -> bool { + self.name == rhs.name + } +} + +impl<'a> PartialOrd for BTS<'a> { + fn partial_cmp(&self, rhs: &BTS<'a>) -> Option<Ordering> { + Some(self.cmp(rhs)) + } +} + +impl<'a> Ord for BTS<'a> { + fn cmp(&self, rhs: &BTS<'a>) -> Ordering { + self.name.cmp(rhs.name) + } +} + +#[derive(Clone)] +struct RCRCData<'a> { + name: &'static str, + mark: Cell<u32>, + children: (Option<&'a RCRC<'a>>, Option<&'a RCRC<'a>>), +} +#[derive(Clone)] +struct RCRC<'a>(Rc<RefCell<RCRCData<'a>>>); + +impl<'a> Named for RCRC<'a> { + fn new(name: &'static str) -> Self { + RCRC(Rc::new(RefCell::new(RCRCData { + name: name, mark: Cell::new(0), children: (None, None), }))) + } + fn name(&self) -> &str { self.0.borrow().name } +} + +impl<'a> Marked<u32> for RCRC<'a> { + fn mark(&self) -> u32 { self.0.borrow().mark.get() } + fn set_mark(&self, mark: u32) { self.0.borrow().mark.set(mark); } +} + +impl<'a> Children<'a> for RCRC<'a> { + fn count_children(&self) -> usize { 2 } + fn descend_one_child<C>(&self, context: &mut C, index: usize) + where C: Context + PrePost<Self>, Self: Sized + { + let children = &self.0.borrow().children; + let child = match index { + 0 => if let Some(child) = children.0 { child } else { return; }, + 1 => if let Some(child) = children.1 { child } else { return; }, + _ => panic!("bad children"), + }; + // println!("S2 {} descending into child {} at index {}", self.name, child.name, index); + child.descend_into_self(context); + } +} +#[derive(Clone)] +struct ARCRCData<'a> { + name: &'static str, + mark: Cell<u32>, + children: (Option<&'a ARCRC<'a>>, Option<&'a ARCRC<'a>>), +} +#[derive(Clone)] +struct ARCRC<'a>(Arc<RefCell<ARCRCData<'a>>>); + +impl<'a> Named for ARCRC<'a> { + fn new(name: &'static str) -> Self { + ARCRC(Arc::new(RefCell::new(ARCRCData { + name: name, mark: Cell::new(0), children: (None, None), }))) + } + fn name(&self) -> &str { self.0.borrow().name } +} + +impl<'a> Marked<u32> for ARCRC<'a> { + fn mark(&self) -> u32 { self.0.borrow().mark.get() } + fn set_mark(&self, mark: u32) { self.0.borrow().mark.set(mark); } +} + +impl<'a> Children<'a> for ARCRC<'a> { + fn count_children(&self) -> usize { 2 } + fn descend_one_child<C>(&self, context: &mut C, index: usize) + where C: Context + PrePost<Self>, Self: Sized + { + let children = &self.0.borrow().children; + match index { + 0 => if let Some(ref child) = children.0 { + child.descend_into_self(context); + }, + 1 => if let Some(ref child) = children.1 { + child.descend_into_self(context); + }, + _ => panic!("bad children!"), + } + } +} + +#[derive(Clone)] +struct ARCMData<'a> { + mark: Cell<u32>, + children: (Option<&'a ARCM<'a>>, Option<&'a ARCM<'a>>), +} + +#[derive(Clone)] +struct ARCM<'a>(&'static str, Arc<Mutex<ARCMData<'a>>>); + +impl<'a> Named for ARCM<'a> { + fn new(name: &'static str) -> Self { + ARCM(name, Arc::new(Mutex::new(ARCMData { + mark: Cell::new(0), children: (None, None), }))) + } + fn name(&self) -> &str { self.0 } +} + +impl<'a> Marked<u32> for ARCM<'a> { + fn mark(&self) -> u32 { self.1.lock().unwrap().mark.get() } + fn set_mark(&self, mark: u32) { self.1.lock().unwrap().mark.set(mark); } +} + +impl<'a> Children<'a> for ARCM<'a> { + fn count_children(&self) -> usize { 2 } + fn descend_one_child<C>(&self, context: &mut C, index: usize) + where C: Context + PrePost<Self>, Self: Sized + { + let ref children = if let Ok(data) = self.1.try_lock() { + data.children + } else { return; }; + match index { + 0 => if let Some(ref child) = children.0 { + child.descend_into_self(context); + }, + 1 => if let Some(ref child) = children.1 { + child.descend_into_self(context); + }, + _ => panic!("bad children!"), + } + } +} + +#[derive(Clone)] +struct ARCRWData<'a> { + name: &'static str, + mark: Cell<u32>, + children: (Option<&'a ARCRW<'a>>, Option<&'a ARCRW<'a>>), +} + +#[derive(Clone)] +struct ARCRW<'a>(Arc<RwLock<ARCRWData<'a>>>); + +impl<'a> Named for ARCRW<'a> { + fn new(name: &'static str) -> Self { + ARCRW(Arc::new(RwLock::new(ARCRWData { + name: name, mark: Cell::new(0), children: (None, None), }))) + } + fn name(&self) -> &str { self.0.read().unwrap().name } +} + +impl<'a> Marked<u32> for ARCRW<'a> { + fn mark(&self) -> u32 { self.0.read().unwrap().mark.get() } + fn set_mark(&self, mark: u32) { self.0.read().unwrap().mark.set(mark); } +} + +impl<'a> Children<'a> for ARCRW<'a> { + fn count_children(&self) -> usize { 2 } + fn descend_one_child<C>(&self, context: &mut C, index: usize) + where C: Context + PrePost<Self>, Self: Sized + { + let children = &self.0.read().unwrap().children; + match index { + 0 => if let Some(ref child) = children.0 { + child.descend_into_self(context); + }, + 1 => if let Some(ref child) = children.1 { + child.descend_into_self(context); + }, + _ => panic!("bad children!"), + } + } +} + +trait Context { + fn next_index(&mut self, len: usize) -> usize; + fn should_act(&self) -> bool; + fn increase_visited(&mut self); + fn increase_skipped(&mut self); + fn increase_depth(&mut self); + fn decrease_depth(&mut self); +} + +trait PrePost<T> { + fn pre(&mut self, _: &T); + fn post(&mut self, _: &T); + fn hit_limit(&mut self, _: &T); +} + +trait Children<'a> { + fn count_children(&self) -> usize; + fn descend_one_child<C>(&self, context: &mut C, index: usize) + where C: Context + PrePost<Self>, Self: Sized; + + fn next_child<C>(&self, context: &mut C) + where C: Context + PrePost<Self>, Self: Sized + { + let index = context.next_index(self.count_children()); + self.descend_one_child(context, index); + } + + fn descend_into_self<C>(&self, context: &mut C) + where C: Context + PrePost<Self>, Self: Sized + { + context.pre(self); + if context.should_act() { + context.increase_visited(); + context.increase_depth(); + self.next_child(context); + context.decrease_depth(); + } else { + context.hit_limit(self); + context.increase_skipped(); + } + context.post(self); + } + + fn descend<'b, C>(&self, c: &Cell<Option<&'b Self>>, context: &mut C) + where C: Context + PrePost<Self>, Self: Sized + { + if let Some(r) = c.get() { + r.descend_into_self(context); + } + } +} + +impl<'a> Children<'a> for S<'a> { + fn count_children(&self) -> usize { 1 } + fn descend_one_child<C>(&self, context: &mut C, _: usize) + where C: Context + PrePost<Self>, Self: Sized { + self.descend(&self.next, context); + } +} + +impl<'a> Children<'a> for S2<'a> { + fn count_children(&self) -> usize { 2 } + fn descend_one_child<C>(&self, context: &mut C, index: usize) + where C: Context + PrePost<Self>, Self: Sized + { + let children = self.next.get(); + let child = match index { + 0 => if let Some(child) = children.0 { child } else { return; }, + 1 => if let Some(child) = children.1 { child } else { return; }, + _ => panic!("bad children"), + }; + // println!("S2 {} descending into child {} at index {}", self.name, child.name, index); + child.descend_into_self(context); + } +} + +impl<'a> Children<'a> for V<'a> { + fn count_children(&self) -> usize { self.contents.len() } + fn descend_one_child<C>(&self, context: &mut C, index: usize) + where C: Context + PrePost<Self>, Self: Sized + { + if let Some(child) = self.contents[index].get() { + child.descend_into_self(context); + } + } +} + +impl<'a> Children<'a> for H<'a> { + fn count_children(&self) -> usize { 1 } + fn descend_one_child<C>(&self, context: &mut C, _: usize) + where C: Context + PrePost<Self>, Self: Sized + { + self.descend(&self.next, context); + } +} + +impl<'a> Children<'a> for HM<'a> { + fn count_children(&self) -> usize { + if let Some(m) = self.contents.get() { 2 * m.iter().count() } else { 0 } + } + fn descend_one_child<C>(&self, context: &mut C, index: usize) + where C: Context + PrePost<Self>, Self: Sized + { + if let Some(ref hm) = self.contents.get() { + for (k, v) in hm.iter().nth(index / 2) { + [k, v][index % 2].descend_into_self(context); + } + } + } +} + +impl<'a> Children<'a> for VD<'a> { + fn count_children(&self) -> usize { + if let Some(d) = self.contents.get() { d.iter().count() } else { 0 } + } + fn descend_one_child<C>(&self, context: &mut C, index: usize) + where C: Context + PrePost<Self>, Self: Sized + { + if let Some(ref vd) = self.contents.get() { + for r in vd.iter().nth(index) { + r.descend_into_self(context); + } + } + } +} + +impl<'a> Children<'a> for VM<'a> { + fn count_children(&self) -> usize { + if let Some(m) = self.contents.get() { m.iter().count() } else { 0 } + } + fn descend_one_child<C>(&self, context: &mut C, index: usize) + where C: Context + PrePost<VM<'a>> + { + if let Some(ref vd) = self.contents.get() { + for (_idx, r) in vd.iter().nth(index) { + r.descend_into_self(context); + } + } + } +} + +impl<'a> Children<'a> for LL<'a> { + fn count_children(&self) -> usize { + if let Some(l) = self.contents.get() { l.iter().count() } else { 0 } + } + fn descend_one_child<C>(&self, context: &mut C, index: usize) + where C: Context + PrePost<LL<'a>> + { + if let Some(ref ll) = self.contents.get() { + for r in ll.iter().nth(index) { + r.descend_into_self(context); + } + } + } +} + +impl<'a> Children<'a> for BH<'a> { + fn count_children(&self) -> usize { + if let Some(h) = self.contents.get() { h.iter().count() } else { 0 } + } + fn descend_one_child<C>(&self, context: &mut C, index: usize) + where C: Context + PrePost<BH<'a>> + { + if let Some(ref bh) = self.contents.get() { + for r in bh.iter().nth(index) { + r.descend_into_self(context); + } + } + } +} + +impl<'a> Children<'a> for BTM<'a> { + fn count_children(&self) -> usize { + if let Some(m) = self.contents.get() { 2 * m.iter().count() } else { 0 } + } + fn descend_one_child<C>(&self, context: &mut C, index: usize) + where C: Context + PrePost<BTM<'a>> + { + if let Some(ref bh) = self.contents.get() { + for (k, v) in bh.iter().nth(index / 2) { + [k, v][index % 2].descend_into_self(context); + } + } + } +} + +impl<'a> Children<'a> for BTS<'a> { + fn count_children(&self) -> usize { + if let Some(s) = self.contents.get() { s.iter().count() } else { 0 } + } + fn descend_one_child<C>(&self, context: &mut C, index: usize) + where C: Context + PrePost<BTS<'a>> + { + if let Some(ref bh) = self.contents.get() { + for r in bh.iter().nth(index) { + r.descend_into_self(context); + } + } + } +} + +#[derive(Copy, Clone)] +struct ContextData { + curr_depth: usize, + max_depth: usize, + visited: usize, + max_visits: usize, + skipped: usize, + curr_mark: u32, + saw_prev_marked: bool, + control_bits: u64, +} + +impl Context for ContextData { + fn next_index(&mut self, len: usize) -> usize { + if len < 2 { return 0; } + let mut pow2 = len.next_power_of_two(); + let _pow2_orig = pow2; + let mut idx = 0; + let mut bits = self.control_bits; + while pow2 > 1 { + idx = (idx << 1) | (bits & 1) as usize; + bits = bits >> 1; + pow2 = pow2 >> 1; + } + idx = idx % len; + // println!("next_index({} [{:b}]) says {}, pre(bits): {:b} post(bits): {:b}", + // len, _pow2_orig, idx, self.control_bits, bits); + self.control_bits = bits; + return idx; + } + fn should_act(&self) -> bool { + self.curr_depth < self.max_depth && self.visited < self.max_visits + } + fn increase_visited(&mut self) { self.visited += 1; } + fn increase_skipped(&mut self) { self.skipped += 1; } + fn increase_depth(&mut self) { self.curr_depth += 1; } + fn decrease_depth(&mut self) { self.curr_depth -= 1; } +} + +impl<T:Named+Marked<u32>> PrePost<T> for ContextData { + fn pre(&mut self, t: &T) { + for _ in 0..self.curr_depth { + if PRINT { print!(" "); } + } + if PRINT { println!("prev {}", t.name()); } + if t.mark() == self.curr_mark { + for _ in 0..self.curr_depth { + if PRINT { print!(" "); } + } + if PRINT { println!("(probably previously marked)"); } + self.saw_prev_marked = true; + } + t.set_mark(self.curr_mark); + } + fn post(&mut self, t: &T) { + for _ in 0..self.curr_depth { + if PRINT { print!(" "); } + } + if PRINT { println!("post {}", t.name()); } + } + fn hit_limit(&mut self, t: &T) { + for _ in 0..self.curr_depth { + if PRINT { print!(" "); } + } + if PRINT { println!("LIMIT {}", t.name()); } + } +} |