|
|
// ancestors.rs
|
|
|
//
|
|
|
// Copyright 2018 Georges Racinet <gracinet@anybox.fr>
|
|
|
//
|
|
|
// This software may be used and distributed according to the terms of the
|
|
|
// GNU General Public License version 2 or any later version.
|
|
|
|
|
|
//! Rust versions of generic DAG ancestors algorithms for Mercurial
|
|
|
|
|
|
use super::{Graph, GraphError, Revision, NULL_REVISION};
|
|
|
use std::collections::{BinaryHeap, HashSet};
|
|
|
|
|
|
/// Iterator over the ancestors of a given list of revisions
|
|
|
/// This is a generic type, defined and implemented for any Graph, so that
|
|
|
/// it's easy to
|
|
|
///
|
|
|
/// - unit test in pure Rust
|
|
|
/// - bind to main Mercurial code, potentially in several ways and have these
|
|
|
/// bindings evolve over time
|
|
|
pub struct AncestorsIterator<G: Graph> {
|
|
|
graph: G,
|
|
|
visit: BinaryHeap<Revision>,
|
|
|
seen: HashSet<Revision>,
|
|
|
stoprev: Revision,
|
|
|
}
|
|
|
|
|
|
impl<G: Graph> AncestorsIterator<G> {
|
|
|
/// Constructor.
|
|
|
///
|
|
|
/// if `inclusive` is true, then the init revisions are emitted in
|
|
|
/// particular, otherwise iteration starts from their parents.
|
|
|
pub fn new<I>(
|
|
|
graph: G,
|
|
|
initrevs: I,
|
|
|
stoprev: Revision,
|
|
|
inclusive: bool,
|
|
|
) -> Result<Self, GraphError>
|
|
|
where
|
|
|
I: IntoIterator<Item = Revision>,
|
|
|
{
|
|
|
let filtered_initrevs = initrevs.into_iter().filter(|&r| r >= stoprev);
|
|
|
if inclusive {
|
|
|
let visit: BinaryHeap<Revision> = filtered_initrevs.collect();
|
|
|
let seen = visit.iter().map(|&x| x).collect();
|
|
|
return Ok(AncestorsIterator {
|
|
|
visit: visit,
|
|
|
seen: seen,
|
|
|
stoprev: stoprev,
|
|
|
graph: graph,
|
|
|
});
|
|
|
}
|
|
|
let mut this = AncestorsIterator {
|
|
|
visit: BinaryHeap::new(),
|
|
|
seen: HashSet::new(),
|
|
|
stoprev: stoprev,
|
|
|
graph: graph,
|
|
|
};
|
|
|
this.seen.insert(NULL_REVISION);
|
|
|
for rev in filtered_initrevs {
|
|
|
let parents = this.graph.parents(rev)?;
|
|
|
this.conditionally_push_rev(parents.0);
|
|
|
this.conditionally_push_rev(parents.1);
|
|
|
}
|
|
|
Ok(this)
|
|
|
}
|
|
|
|
|
|
#[inline]
|
|
|
fn conditionally_push_rev(&mut self, rev: Revision) {
|
|
|
if self.stoprev <= rev && !self.seen.contains(&rev) {
|
|
|
self.seen.insert(rev);
|
|
|
self.visit.push(rev);
|
|
|
}
|
|
|
}
|
|
|
|
|
|
/// Consumes partially the iterator to tell if the given target
|
|
|
/// revision
|
|
|
/// is in the ancestors it emits.
|
|
|
/// This is meant for iterators actually dedicated to that kind of
|
|
|
/// purpose
|
|
|
pub fn contains(&mut self, target: Revision) -> bool {
|
|
|
if self.seen.contains(&target) && target != NULL_REVISION {
|
|
|
return true;
|
|
|
}
|
|
|
for rev in self {
|
|
|
if rev == target {
|
|
|
return true;
|
|
|
}
|
|
|
if rev < target {
|
|
|
return false;
|
|
|
}
|
|
|
}
|
|
|
false
|
|
|
}
|
|
|
}
|
|
|
|
|
|
/// Main implementation.
|
|
|
///
|
|
|
/// The algorithm is the same as in `_lazyancestorsiter()` from `ancestors.py`
|
|
|
/// with a few non crucial differences:
|
|
|
///
|
|
|
/// - there's no filtering of invalid parent revisions. Actually, it should be
|
|
|
/// consistent and more efficient to filter them from the end caller.
|
|
|
/// - we don't have the optimization for adjacent revs
|
|
|
/// (case where p1 == rev-1), because it amounts to update the first element
|
|
|
/// of the heap without sifting, which Rust's BinaryHeap doesn't let us do.
|
|
|
/// - we save a few pushes by comparing with `stoprev` before pushing
|
|
|
///
|
|
|
/// Error treatment:
|
|
|
/// We swallow the possible GraphError of conditionally_push_parents() to
|
|
|
/// respect the Iterator trait in a simple manner: never emitting parents
|
|
|
/// for the returned revision. We finds this good enough for now, because:
|
|
|
///
|
|
|
/// - there's a good chance that invalid revisionss are fed from the start,
|
|
|
/// and `new()` doesn't swallow the error result.
|
|
|
/// - this is probably what the Python implementation produces anyway, due
|
|
|
/// to filtering at each step, and Python code is currently the only
|
|
|
/// concrete caller we target, so we shouldn't need a finer error treatment
|
|
|
/// for the time being.
|
|
|
impl<G: Graph> Iterator for AncestorsIterator<G> {
|
|
|
type Item = Revision;
|
|
|
|
|
|
fn next(&mut self) -> Option<Revision> {
|
|
|
let current = match self.visit.peek() {
|
|
|
None => {
|
|
|
return None;
|
|
|
}
|
|
|
Some(c) => *c,
|
|
|
};
|
|
|
let parents = self
|
|
|
.graph
|
|
|
.parents(current)
|
|
|
.unwrap_or((NULL_REVISION, NULL_REVISION));
|
|
|
let p1 = parents.0;
|
|
|
if p1 < self.stoprev || self.seen.contains(&p1) {
|
|
|
self.visit.pop();
|
|
|
} else {
|
|
|
*(self.visit.peek_mut().unwrap()) = p1;
|
|
|
self.seen.insert(p1);
|
|
|
};
|
|
|
|
|
|
self.conditionally_push_rev(parents.1);
|
|
|
Some(current)
|
|
|
}
|
|
|
}
|
|
|
|
|
|
#[cfg(test)]
|
|
|
mod tests {
|
|
|
|
|
|
use super::*;
|
|
|
|
|
|
#[derive(Clone, Debug)]
|
|
|
struct Stub;
|
|
|
|
|
|
/// This is the same as the dict from test-ancestors.py
|
|
|
impl Graph for Stub {
|
|
|
fn parents(
|
|
|
&self,
|
|
|
rev: Revision,
|
|
|
) -> Result<(Revision, Revision), GraphError> {
|
|
|
match rev {
|
|
|
0 => Ok((-1, -1)),
|
|
|
1 => Ok((0, -1)),
|
|
|
2 => Ok((1, -1)),
|
|
|
3 => Ok((1, -1)),
|
|
|
4 => Ok((2, -1)),
|
|
|
5 => Ok((4, -1)),
|
|
|
6 => Ok((4, -1)),
|
|
|
7 => Ok((4, -1)),
|
|
|
8 => Ok((-1, -1)),
|
|
|
9 => Ok((6, 7)),
|
|
|
10 => Ok((5, -1)),
|
|
|
11 => Ok((3, 7)),
|
|
|
12 => Ok((9, -1)),
|
|
|
13 => Ok((8, -1)),
|
|
|
r => Err(GraphError::ParentOutOfRange(r)),
|
|
|
}
|
|
|
}
|
|
|
}
|
|
|
|
|
|
fn list_ancestors<G: Graph>(
|
|
|
graph: G,
|
|
|
initrevs: Vec<Revision>,
|
|
|
stoprev: Revision,
|
|
|
inclusive: bool,
|
|
|
) -> Vec<Revision> {
|
|
|
AncestorsIterator::new(graph, initrevs, stoprev, inclusive)
|
|
|
.unwrap()
|
|
|
.collect()
|
|
|
}
|
|
|
|
|
|
#[test]
|
|
|
/// Same tests as test-ancestor.py, without membership
|
|
|
/// (see also test-ancestor.py.out)
|
|
|
fn test_list_ancestor() {
|
|
|
assert_eq!(list_ancestors(Stub, vec![], 0, false), vec![]);
|
|
|
assert_eq!(
|
|
|
list_ancestors(Stub, vec![11, 13], 0, false),
|
|
|
vec![8, 7, 4, 3, 2, 1, 0]
|
|
|
);
|
|
|
assert_eq!(list_ancestors(Stub, vec![1, 3], 0, false), vec![1, 0]);
|
|
|
assert_eq!(
|
|
|
list_ancestors(Stub, vec![11, 13], 0, true),
|
|
|
vec![13, 11, 8, 7, 4, 3, 2, 1, 0]
|
|
|
);
|
|
|
assert_eq!(list_ancestors(Stub, vec![11, 13], 6, false), vec![8, 7]);
|
|
|
assert_eq!(
|
|
|
list_ancestors(Stub, vec![11, 13], 6, true),
|
|
|
vec![13, 11, 8, 7]
|
|
|
);
|
|
|
assert_eq!(list_ancestors(Stub, vec![11, 13], 11, true), vec![13, 11]);
|
|
|
assert_eq!(list_ancestors(Stub, vec![11, 13], 12, true), vec![13]);
|
|
|
assert_eq!(
|
|
|
list_ancestors(Stub, vec![10, 1], 0, true),
|
|
|
vec![10, 5, 4, 2, 1, 0]
|
|
|
);
|
|
|
}
|
|
|
|
|
|
#[test]
|
|
|
/// Corner case that's not directly in test-ancestors.py, but
|
|
|
/// that happens quite often, as demonstrated by running the whole
|
|
|
/// suite.
|
|
|
/// For instance, run tests/test-obsolete-checkheads.t
|
|
|
fn test_nullrev_input() {
|
|
|
let mut iter =
|
|
|
AncestorsIterator::new(Stub, vec![-1], 0, false).unwrap();
|
|
|
assert_eq!(iter.next(), None)
|
|
|
}
|
|
|
|
|
|
#[test]
|
|
|
fn test_contains() {
|
|
|
let mut lazy =
|
|
|
AncestorsIterator::new(Stub, vec![10, 1], 0, true).unwrap();
|
|
|
assert!(lazy.contains(1));
|
|
|
assert!(!lazy.contains(3));
|
|
|
|
|
|
let mut lazy =
|
|
|
AncestorsIterator::new(Stub, vec![0], 0, false).unwrap();
|
|
|
assert!(!lazy.contains(NULL_REVISION));
|
|
|
}
|
|
|
|
|
|
/// A corrupted Graph, supporting error handling tests
|
|
|
struct Corrupted;
|
|
|
|
|
|
impl Graph for Corrupted {
|
|
|
fn parents(
|
|
|
&self,
|
|
|
rev: Revision,
|
|
|
) -> Result<(Revision, Revision), GraphError> {
|
|
|
match rev {
|
|
|
1 => Ok((0, -1)),
|
|
|
r => Err(GraphError::ParentOutOfRange(r)),
|
|
|
}
|
|
|
}
|
|
|
}
|
|
|
|
|
|
#[test]
|
|
|
fn test_initrev_out_of_range() {
|
|
|
// inclusive=false looks up initrev's parents right away
|
|
|
match AncestorsIterator::new(Stub, vec![25], 0, false) {
|
|
|
Ok(_) => panic!("Should have been ParentOutOfRange"),
|
|
|
Err(e) => assert_eq!(e, GraphError::ParentOutOfRange(25)),
|
|
|
}
|
|
|
}
|
|
|
|
|
|
#[test]
|
|
|
fn test_next_out_of_range() {
|
|
|
// inclusive=false looks up initrev's parents right away
|
|
|
let mut iter =
|
|
|
AncestorsIterator::new(Corrupted, vec![1], 0, false).unwrap();
|
|
|
assert_eq!(iter.next(), Some(0));
|
|
|
assert_eq!(iter.next(), None);
|
|
|
}
|
|
|
}
|
|
|
|
