Patchwork [1,of,2,V5] rust: rustlazyancestors.__contains__

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Submitter Georges Racinet
Date Oct. 15, 2018, 9:49 a.m.
Message ID <a7cbd02e936e67240682.1539596989@ishtar>
Download mbox | patch
Permalink /patch/36015/
State Accepted
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Georges Racinet - Oct. 15, 2018, 9:49 a.m.
# HG changeset patch
# User Georges Racinet <gracinet@anybox.fr>
# Date 1539018701 -7200
#      Mon Oct 08 19:11:41 2018 +0200
# Node ID a7cbd02e936e6724068219ee4c1c50dd4da2b22c
# Parent  9cadb0f5f2279a60a79b1d0e50eccd60638495c0
# EXP-Topic rustancestors-contains
rust: rustlazyancestors.__contains__

This changeset provides a Rust implementation of
the iteration performed by lazyancestor.__contains__

It has the advantage over the Python iteration to use
the 'seen' set encapsuled into the dedicated iterator (self._containsiter),
rather than storing emitted items in another set (self._containsseen),
and hence should reduce the memory footprint.

Also, there's no need to convert intermediate emitted revisions back into
Python integers.

At this point, it would be tempting to implement the whole lazyancestor object
in Rust, but that would lead to more C wrapping code (two objects) for
little expected benefits.
Yuya Nishihara - Oct. 15, 2018, 2:55 p.m.
On Mon, 15 Oct 2018 11:49:49 +0200, Georges Racinet wrote:
> # HG changeset patch
> # User Georges Racinet <gracinet@anybox.fr>
> # Date 1539018701 -7200
> #      Mon Oct 08 19:11:41 2018 +0200
> # Node ID a7cbd02e936e6724068219ee4c1c50dd4da2b22c
> # Parent  9cadb0f5f2279a60a79b1d0e50eccd60638495c0
> # EXP-Topic rustancestors-contains
> rust: rustlazyancestors.__contains__

Queued, thanks.

Patch

diff -r 9cadb0f5f227 -r a7cbd02e936e mercurial/ancestor.py
--- a/mercurial/ancestor.py	Thu Sep 27 16:55:44 2018 +0200
+++ b/mercurial/ancestor.py	Mon Oct 08 19:11:41 2018 +0200
@@ -383,7 +383,7 @@ 
             self._containsiter = None
             return False
 
-class rustlazyancestors(lazyancestors):
+class rustlazyancestors(object):
 
     def __init__(self, index, revs, stoprev=0, inclusive=False):
         self._index = index
@@ -395,12 +395,26 @@ 
         # constructor (from C code) doesn't understand anything else yet
         self._initrevs = initrevs = list(revs)
 
-        self._containsseen = set()
         self._containsiter = parsers.rustlazyancestors(
             index, initrevs, stoprev, inclusive)
 
+    def __nonzero__(self):
+        """False if the set is empty, True otherwise.
+
+        It's better to duplicate this essentially trivial method than
+        to subclass lazyancestors
+        """
+        try:
+            next(iter(self))
+            return True
+        except StopIteration:
+            return False
+
     def __iter__(self):
         return parsers.rustlazyancestors(self._index,
                                          self._initrevs,
                                          self._stoprev,
                                          self._inclusive)
+
+    def __contains__(self, target):
+        return target in self._containsiter
diff -r 9cadb0f5f227 -r a7cbd02e936e mercurial/cext/revlog.c
--- a/mercurial/cext/revlog.c	Thu Sep 27 16:55:44 2018 +0200
+++ b/mercurial/cext/revlog.c	Mon Oct 08 19:11:41 2018 +0200
@@ -2316,6 +2316,7 @@ 
 	int inclusive);
 void rustlazyancestors_drop(rustlazyancestorsObject *self);
 int rustlazyancestors_next(rustlazyancestorsObject *self);
+int rustlazyancestors_contains(rustlazyancestorsObject *self, long rev);
 
 /* CPython instance methods */
 static int rustla_init(rustlazyancestorsObject *self,
@@ -2395,6 +2396,24 @@ 
 	return PyInt_FromLong(res);
 }
 
+static int rustla_contains(rustlazyancestorsObject *self, PyObject *rev) {
+	if (!(PyInt_Check(rev))) {
+		return 0;
+	}
+	return rustlazyancestors_contains(self->iter, PyInt_AS_LONG(rev));
+}
+
+static PySequenceMethods rustla_sequence_methods = {
+	0,                       /* sq_length */
+	0,                       /* sq_concat */
+	0,                       /* sq_repeat */
+	0,                       /* sq_item */
+	0,                       /* sq_slice */
+	0,                       /* sq_ass_item */
+	0,                       /* sq_ass_slice */
+	(objobjproc)rustla_contains, /* sq_contains */
+};
+
 static PyTypeObject rustlazyancestorsType = {
 	PyVarObject_HEAD_INIT(NULL, 0) /* header */
 	"parsers.rustlazyancestors",           /* tp_name */
@@ -2407,7 +2426,7 @@ 
 	0,                         /* tp_compare */
 	0,                         /* tp_repr */
 	0,                         /* tp_as_number */
-	0,                         /* tp_as_sequence */
+	&rustla_sequence_methods,  /* tp_as_sequence */
 	0,                         /* tp_as_mapping */
 	0,                         /* tp_hash */
 	0,                         /* tp_call */
diff -r 9cadb0f5f227 -r a7cbd02e936e rust/hg-core/src/ancestors.rs
--- a/rust/hg-core/src/ancestors.rs	Thu Sep 27 16:55:44 2018 +0200
+++ b/rust/hg-core/src/ancestors.rs	Mon Oct 08 19:11:41 2018 +0200
@@ -80,6 +80,26 @@ 
         self.conditionally_push_rev(parents.1);
         Ok(())
     }
+
+    /// 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.
@@ -203,6 +223,18 @@ 
         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;
 
diff -r 9cadb0f5f227 -r a7cbd02e936e rust/hg-direct-ffi/src/ancestors.rs
--- a/rust/hg-direct-ffi/src/ancestors.rs	Thu Sep 27 16:55:44 2018 +0200
+++ b/rust/hg-direct-ffi/src/ancestors.rs	Mon Oct 08 19:11:41 2018 +0200
@@ -139,6 +139,27 @@ 
     as_ref.next().unwrap_or(NULL_REVISION) as c_long
 }
 
+#[no_mangle]
+pub extern "C" fn rustlazyancestors_contains(
+    raw: *mut AncestorsIterator<Index>,
+    target: c_long,
+) -> c_int {
+    raw_contains(raw, target)
+}
+
+/// Testable (for any Graph) version of rustlazayancestors_next
+#[inline]
+fn raw_contains<G: Graph>(
+    raw: *mut AncestorsIterator<G>,
+    target: c_long,
+) -> c_int {
+    let as_ref = unsafe { &mut *raw };
+    if as_ref.contains(target as Revision) {
+        return 1;
+    }
+    0
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -226,4 +247,18 @@ 
     fn test_init_err_out_of_range() {
         assert!(stub_raw_init_from_vec(vec![25], 0, 0).is_null());
     }
+
+    #[test]
+    fn test_contains() {
+        let raw = stub_raw_init_from_vec(vec![5, 6], 0, 1);
+        assert_eq!(raw_contains(raw, 5), 1);
+        assert_eq!(raw_contains(raw, 2), 1);
+    }
+
+    #[test]
+    fn test_contains_exclusive() {
+        let raw = stub_raw_init_from_vec(vec![5, 6], 0, 0);
+        assert_eq!(raw_contains(raw, 5), 0);
+        assert_eq!(raw_contains(raw, 2), 1);
+    }
 }
diff -r 9cadb0f5f227 -r a7cbd02e936e rust/hg-direct-ffi/src/lib.rs
--- a/rust/hg-direct-ffi/src/lib.rs	Thu Sep 27 16:55:44 2018 +0200
+++ b/rust/hg-direct-ffi/src/lib.rs	Mon Oct 08 19:11:41 2018 +0200
@@ -13,4 +13,7 @@ 
 extern crate libc;
 
 mod ancestors;
-pub use ancestors::{rustlazyancestors_drop, rustlazyancestors_init, rustlazyancestors_next};
+pub use ancestors::{
+    rustlazyancestors_contains, rustlazyancestors_drop,
+    rustlazyancestors_init, rustlazyancestors_next,
+};