--- /dev/null
+/* concurrentlist.vala
+ *
+ * Copyright (C) 2011 Maciej Piechotka
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * Author:
+ * Maciej Piechotka <uzytkownik2@gmail.com>
+ */
+
+/**
+ * A single-linked list. This implementation is based on
+ * [[www.cse.yorku.ca/~ruppert/papers/lfll.pdf|Mikhail Fomitchev and Eric Ruppert paper ]].
+ *
+ * Many threads are allowed to operate on the same structure as well as modification
+ * of structure during iteration is allowed. However the change may not be immidiatly
+ * visible to other threads.
+ */
+public class Gee.ConcurrentList<G> : AbstractList<G> {
+ /**
+ * The elements' equality testing function.
+ */
+ public Gee.EqualDataFunc equal_func { private set; get; }
+
+ /**
+ * Construct new, empty single linked list
+ *
+ * If not provided, the function parameter is requested to the
+ * {@link Functions} function factory methods.
+ *
+ * @param equal_func an optional element equality testing function
+ */
+ public ConcurrentList (owned Gee.EqualDataFunc? equal_func = null) {
+ if (equal_func == null)
+ equal_func = Gee.Functions.get_equal_func_for (typeof (G));
+ this.equal_func = (owned)equal_func;
+ _head = new Node<G>.head ();
+ HazardPointer.set_pointer<Node<G>> (&_tail, _head);
+ }
+
+ ~ConcurrentList () {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ _head = null;
+ HazardPointer.set_pointer<Node<G>> (&_tail, null);
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public override bool read_only {
+ get {
+ return false;
+ }
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public override int size {
+ get {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ int result = 0;
+ for (var iter = iterator (); iter.next ();)
+ result++;
+ return result;
+ }
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public override bool is_empty {
+ get {
+ return !iterator ().next ();
+ }
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public override bool contains (G item) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ for (var iter = iterator (); iter.next ();)
+ if (equal_func (item, iter.get ()))
+ return true;
+ return false;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public override bool add (G item) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ Node<G> node = new Node<G> (item);
+ node.insert (get_tail (), null);
+ return true;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public override bool remove (G item) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ Gee.Iterator<G> iter = iterator ();
+ while (iter.next ()) {
+ if (equal_func (item, iter.get ())) {
+ iter.remove ();
+ return true;
+ }
+ }
+ return false;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public override void clear () {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ var iter = iterator ();
+ while (iter.next ())
+ iter.remove ();
+ HazardPointer.set_pointer (&_tail, _head);
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public override Gee.Iterator<G> iterator () {
+ return new Iterator<G> (_head);
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public override ListIterator<G> list_iterator () {
+ return new Iterator<G> (_head);
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public override G? get (int index) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ assert (index >= 0);
+ for (var iterator = iterator (); iterator.next ();)
+ if (index-- == 0)
+ return iterator.get ();
+ assert_not_reached ();
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public override void set (int index, G item) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ assert (index >= 0);
+ for (var iterator = list_iterator (); iterator.next ();) {
+ if (index-- == 0) {
+ iterator.set (item);
+ return;
+ }
+ }
+ assert_not_reached ();
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public override int index_of (G item) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ int index = 0;
+ for (var iterator = list_iterator (); iterator.next (); index++)
+ if (equal_func (item, iterator.get ()))
+ return index;
+ return -1;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public override void insert (int index, G item) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ assert (index >= 0);
+ if (index == 0) {
+ var prev = _head;
+ var next = _head.get_next ();
+ Node<G> new_node = new Node<G> (item);
+ new_node.insert (prev, next);
+ } else {
+ for (var iterator = list_iterator (); iterator.next ();) {
+ if (--index == 0) {
+ iterator.add (item);
+ return;
+ }
+ }
+ assert_not_reached ();
+ }
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public override G remove_at (int index) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ for (var iterator = list_iterator (); iterator.next ();) {
+ if (index-- == 0) {
+ G data = iterator.get ();
+ iterator.remove ();
+ return data;
+ }
+ }
+ assert_not_reached ();
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public override List<G>? slice (int start, int end) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ assert (0 <= start);
+ assert (start <= end);
+ var list = new ConcurrentList<G> (equal_func);
+ var iterator = iterator ();
+ int idx = 0;
+ for (; iterator.next (); idx++)
+ if (idx >= start && idx < end)
+ list.add (iterator.get ());
+ else if (idx >= end)
+ break;
+ assert (idx >= end);
+ return list;
+ }
+
+ private inline Node<G> update_tail () {
+ Node<G> tail = HazardPointer.get_pointer (&_tail);
+ Node.backtrace<G> (ref tail);
+ Node.search_for<G> (null, ref tail);
+ HazardPointer.set_pointer<Node<G>> (&_tail, tail);
+ return tail;
+ }
+
+ private inline Node<G> get_tail () {
+ return update_tail ();
+ }
+
+ private Node<G> _head;
+ private Node<G> *_tail;
+
+ private class Iterator<G> : Object, Gee.Traversable<G>, Gee.Iterator<G>, ListIterator<G> {
+ public Iterator (Node<G> head) {
+ _started = false;
+ _removed = false;
+ _index = -1;
+ _prev = null;
+ _curr = head;
+ }
+
+ public bool next () {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ Node<G>? _old_prev = _removed ? _prev : null;
+ bool success = Node.proceed<G> (ref _prev, ref _curr);
+ if (success) {
+ if (_removed)
+ _prev = _old_prev;
+ _removed = false;
+ _started = true;
+ _index++;
+ }
+ return success;
+ }
+
+ public bool has_next () {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ Node<G>? prev = _prev;
+ Node<G>? curr = _curr;
+ return Node.proceed<G> (ref prev, ref curr);
+ }
+
+ public new G get () {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ assert (valid);
+ return HazardPointer.get_pointer<G> (&_curr._data);
+ }
+
+ public new void set (G item) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ assert (valid);
+#if DEBUG
+ G item_copy = item;
+ stderr.printf (" Setting data %p to %p\n", _curr, item_copy);
+ HazardPointer.set_pointer<G> (&_curr._data, (owned)item_copy);
+#else
+ HazardPointer.set_pointer<G> (&_curr._data, item);
+#endif
+ }
+
+ public void remove () {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ assert (valid);
+ _curr.remove (_prev);
+ _removed = true;
+ _index--;
+ }
+
+ public bool valid {
+ get { return _started && !_removed && _curr != null; }
+ }
+
+ public bool read_only { get { return false; } }
+
+ public int index() {
+ assert (valid);
+ return _index;
+ }
+
+ public void add (G item) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ assert (valid);
+ if (!Node.proceed<G> (ref _prev, ref _curr)) {
+ _prev = (owned)_curr;
+ _curr = null;
+ }
+ Node<G> new_node = new Node<G> (item);
+ new_node.insert (_prev, _curr);
+ _curr = (owned)new_node;
+ _index++;
+ }
+
+ public new void foreach (ForallFunc<G> f) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ if (_started && !_removed)
+ f (HazardPointer.get_pointer<G> (&_curr._data));
+ Node<G>? _old_prev = _removed ? _prev : null;
+ while (Node.proceed<G> (ref _prev, ref _curr)) {
+ if (_removed)
+ _prev = _old_prev;
+ _removed = false;
+ _started = true;
+ _index++;
+ f (HazardPointer.get_pointer<G> (&_curr._data));
+ }
+ }
+
+ public Gee.Iterator<G> stream<A> (owned StreamFunc<G, A> f) {
+ return Gee.Iterator.stream_impl<G, A> (this, (owned)f);
+ }
+
+ public Gee.Iterator<G> filter (owned Predicate<G> f) {
+ return Traversable.filter_impl<G> (this, (owned)f);
+ }
+
+ public Gee.Iterator<G> chop (int offset, int length = -1) {
+ return Traversable.chop_impl<G> (this, offset, length);
+ }
+
+ private bool _started;
+ private bool _removed;
+ private int _index;
+ private Node<G> _prev;
+ private Node<G>? _curr;
+ }
+
+ private class Node<G> {
+ public inline Node (G data) {
+ AtomicPointer.set (&_succ, null);
+ AtomicPointer.set (&_backlink, null);
+ G data_copy = data;
+ G *data_ptr = (owned)data_copy;
+#if DEBUG
+ stderr.printf (" Creating node %p with data %p\n", this, data_ptr);
+#endif
+ AtomicPointer.set (&_data, (owned)data_ptr);
+ }
+
+ public inline Node.head () {
+ AtomicPointer.set (&_succ, null);
+ AtomicPointer.set (&_backlink, null);
+ AtomicPointer.set (&_data, null);
+#if DEBUG
+ stderr.printf (" Creating head node %p\n", this);
+#endif
+ }
+
+ inline ~Node () {
+ HazardPointer.set_pointer<Node<G>> (&_succ, null, 3);
+ HazardPointer.set_pointer<Node<G>> (&_backlink, null);
+#if DEBUG
+ G? old_data = HazardPointer.exchange_pointer (&_data, null);
+ stderr.printf (" Freeing node %p (with data %p)\n", this, old_data);
+#else
+ HazardPointer.set_pointer<G> (&_data, null);
+#endif
+ }
+
+ public static inline bool proceed<G> (ref Node<G> prev, ref Node<G> curr, bool force = false) {
+ Node<G> next = curr.get_next ();
+ while (next != null) {
+ State next_state = next.get_state ();
+ State curr_state;
+ Node<G> curr_next = curr.get_succ (out curr_state);
+ if (next_state != State.MARKED || (curr_state == State.MARKED && curr_next == next))
+ break;
+ if (curr_next == next)
+ next.help_marked (curr);
+ next = curr_next;
+ }
+ bool success = next != null;
+ if (success || force) {
+ prev = (owned)curr;
+ curr = (owned)next;
+#if DEBUG
+ stderr.printf (" Procceed to %p (previous %p)\n", curr, prev);
+#endif
+ }
+ return success;
+ }
+
+ public static inline bool search_for<G> (Node<G>? goal, ref Node<G>? prev) {
+ Node<G>? curr = prev.get_next ();
+ while ((curr != goal || curr != null) && proceed<G> (ref prev, ref curr, true));
+ return curr == goal;
+ }
+
+ public inline bool remove (Node<G> prev_node) {
+#if DEBUG
+ stderr.printf (" Removing %p (previous %p)\n", this, prev_node);
+#endif
+ Node<G>? prev = prev_node;
+ bool result = try_flag (ref prev);
+ if (prev != null)
+ help_flagged (prev);
+ return result;
+ }
+
+ public inline void insert (owned Node<G> prev, Node<G>? next) {
+#if DEBUG
+ stderr.printf (" Inserting %p between %p and %p\n", this, prev, next);
+#endif
+ while (true) {
+ State prev_state;
+ Node<G>? prev_next = get_succ (out prev_state);
+ if (prev_state == State.FLAGGED) {
+ prev_next.help_flagged (prev);
+ } else {
+ set_succ (next, State.NONE);
+ bool result = prev.compare_and_exchange (next, State.NONE, this, State.NONE);
+ if (result)
+ return;
+ prev_next = get_succ (out prev_state);
+ if (prev_state == State.FLAGGED)
+ prev_next.help_flagged (prev);
+ backtrace<G> (ref prev);
+ }
+ search_for<G> (next, ref prev);
+ }
+
+ }
+
+ public inline void help_flagged (Node<G> prev) {
+#if DEBUG
+ stderr.printf (" Help flagging %p (previous %p)\n", this, prev);
+#endif
+ set_backlink (prev);
+ if (get_state () == State.MARKED)
+ try_mark ();
+ help_marked (prev);
+ }
+
+ public inline void try_mark () {
+#if DEBUG
+ stderr.printf (" Try flagging %p\n", this);
+#endif
+ do {
+ Node<G>? next_node = get_next ();
+ bool result = compare_and_exchange (next_node, State.NONE, next_node, State.MARKED);
+ if (!result && get_state () == State.FLAGGED)
+ help_flagged (next_node);
+ } while (get_state () != State.MARKED);
+ }
+
+ public inline void help_marked (Node<G> prev_node) {
+#if DEBUG
+ stderr.printf (" Help marking %p (previous %p)\n", this, prev_node);
+#endif
+ prev_node.compare_and_exchange (this, State.FLAGGED, get_next (), State.NONE);
+ }
+
+ public inline bool try_flag (ref Node<G>? prev_node) {
+#if DEBUG
+ stderr.printf (" Try flagging %p (previous %p)\n", this, prev_node);
+#endif
+ while (true) {
+ if (prev_node.compare_succ (this, State.FLAGGED))
+ return false;
+ bool result = prev_node.compare_and_exchange (this, State.NONE, this, State.FLAGGED);
+ if (result)
+ return true;
+ State result_state;
+ Node<G>? result_node = prev_node.get_succ (out result_state);
+ if (result_node == this && result_state == State.FLAGGED)
+ return false;
+ backtrace<G> (ref prev_node);
+ if (!search_for<G> (this, ref prev_node)) {
+ prev_node = null;
+ return false;
+ }
+ }
+ }
+
+ public static inline void backtrace<G> (ref Node<G>? curr) {
+ while (curr.get_state () == State.MARKED)
+ curr = curr.get_backlink ();
+ }
+
+ public inline bool compare_and_exchange (Node<G>? old_node, State old_state, Node<G>? new_node, State new_state) {
+#if DEBUG
+ bool b = HazardPointer.compare_and_exchange_pointer (&_succ, old_node, new_node, 3, (size_t)old_state, (size_t)new_state);
+ stderr.printf (" Setting %p.succ to (%p, %s) if %p.succ is (%p, %s): %s\n", this, new_node, new_state.to_string (), this, old_node, old_state.to_string (), b ? "success" : "failure");
+ return b;
+#else
+ return HazardPointer.compare_and_exchange_pointer (&_succ, old_node, new_node, 3, (size_t)old_state, (size_t)new_state);
+#endif
+ }
+
+ public inline bool compare_succ (Node<G>? next, State state) {
+ size_t cur = (size_t)AtomicPointer.get (&_succ);
+ return cur == ((size_t)next | (size_t)state);
+ }
+
+ public inline Node<G>? get_next () {
+ return get_succ (null);
+ }
+
+ public inline State get_state () {
+ return (State)((size_t)AtomicPointer.get (&_succ) & 3);
+ }
+
+ public inline Node<G>? get_succ (out State state) {
+ size_t rstate;
+ Node<G>? succ = HazardPointer.get_pointer<Node<G>> (&_succ, 3, out rstate);
+ state = (State)rstate;
+ return (owned)succ;
+ }
+
+ public inline void set_succ (Node<G>? next, State state) {
+#if DEBUG
+ stderr.printf (" Setting %p.succ to (%p, %s)\n", this, next, state.to_string ());
+#endif
+ HazardPointer.set_pointer<Node<G>> (&_succ, next, 3, (size_t)state);
+ }
+
+ public inline Node<G>? get_backlink () {
+ return HazardPointer.get_pointer<Node<G>> (&_backlink);
+ }
+
+ public inline void set_backlink (Node<G>? backlink) {
+#if DEBUG
+ stderr.printf (" Setting backlink from %p to %p\n", this, backlink);
+#endif
+ HazardPointer.compare_and_exchange_pointer<Node<G>> (&_backlink, null, backlink);
+ }
+
+ public Node<G> *_succ;
+ public Node<G> *_backlink;
+ public G *_data;
+ }
+
+ private enum State {
+ NONE = 0,
+ MARKED = 1,
+ FLAGGED = 2
+ }
+}
projects / platform / upstream / libgee.git / commitdiff