#include <cds/details/binary_functor_wrapper.h>
#include <cds/details/make_const_type.h>
#include <cds/urcu/exempt_ptr.h>
+#include <cds/urcu/raw_ptr.h>
+#include <cds/intrusive/details/raw_ptr_disposer.h>
namespace cds { namespace intrusive {
typedef cds::urcu::gc< RCU > gc; ///< Garbage collector
typedef Tag tag; ///< tag
- typedef cds::details::marked_ptr<node, 1> marked_ptr ; ///< marked pointer
- typedef typename gc::template atomic_marked_ptr< marked_ptr> atomic_marked_ptr ; ///< atomic marked pointer specific for GC
+ typedef cds::details::marked_ptr<node, 3> marked_ptr; ///< marked pointer
+ typedef typename gc::template atomic_marked_ptr<marked_ptr> atomic_marked_ptr; ///< atomic marked pointer specific for GC
- atomic_marked_ptr m_pNext ; ///< pointer to the next node in the container
+ atomic_marked_ptr m_pNext; ///< pointer to the next node in the container
node * m_pDelChain; ///< Deleted node chain (local for a thread)
CDS_CONSTEXPR node() CDS_NOEXCEPT
static void clear_links( node_type * pNode )
{
- pNode->m_pNext.store( marked_node_ptr(), memory_model::memory_order_relaxed );
+ pNode->m_pNext.store( marked_node_ptr(), memory_model::memory_order_release );
pNode->m_pDelChain = nullptr;
}
gc::template retire_ptr<clear_and_dispose>( node_traits::to_value_ptr( *pNode ) );
}
+ static void dispose_chain( node_type * pChain )
+ {
+ if ( pChain ) {
+ assert( !gc::is_locked() );
+
+ auto f = [&pChain]() -> cds::urcu::retired_ptr {
+ node_type * p = pChain;
+ if ( p ) {
+ pChain = p->m_pDelChain;
+ return cds::urcu::make_retired_ptr<clear_and_dispose>( node_traits::to_value_ptr( p ));
+ }
+ return cds::urcu::make_retired_ptr<clear_and_dispose>( static_cast<value_type *>(nullptr));
+ };
+ gc::batch_retire(std::ref(f));
+ }
+ }
+
/// Position pointer for item search
struct position {
atomic_node_ptr * pPrev ; ///< Previous node
~position()
{
- assert( !gc::is_locked() );
-
- node_type * chain = pDelChain;
- if ( chain ) {
- auto f = [&chain]() -> cds::urcu::retired_ptr {
- node_type * p = chain;
- chain = p->m_pDelChain;
- return cds::urcu::make_retired_ptr<clear_and_dispose>( node_traits::to_value_ptr( p ));
- };
- gc::batch_retire(std::ref(f));
- }
+ dispose_chain( pDelChain );
}
};
public:
using exempt_ptr = cds::urcu::exempt_ptr< gc, value_type, value_type, clear_and_dispose, void >; ///< pointer to extracted node
+ private:
+ //@cond
+ struct chain_disposer {
+ void operator()( node_type * pChain ) const
+ {
+ dispose_chain( pChain );
+ }
+ };
+ typedef cds::intrusive::details::raw_ptr_disposer< gc, node_type, chain_disposer> raw_ptr_disposer;
+ //@endcond
+
+ public:
+ /// Result of \p get(), \p get_with() functions - pointer to the node found
+ typedef cds::urcu::raw_ptr< gc, value_type, raw_ptr_disposer > raw_ptr;
+
protected:
//@cond
bool unlink_node( position& pos, erase_node_mask nMask )
{
+ assert(gc::is_locked() );
+
// Mark the node (logical deletion)
marked_node_ptr next(pos.pNext, 0);
- if ( pos.pCur->m_pNext.compare_exchange_strong( next, next | nMask, memory_model::memory_order_acq_rel, atomics::memory_order_relaxed )) {
+ if ( pos.pCur->m_pNext.compare_exchange_strong( next, next | nMask, memory_model::memory_order_release, atomics::memory_order_relaxed )) {
// Try physical removal - fast path
marked_node_ptr cur(pos.pCur);
- if ( pos.pPrev->compare_exchange_strong(cur, marked_node_ptr(pos.pNext), memory_model::memory_order_acquire, atomics::memory_order_relaxed) ) {
+ if ( pos.pPrev->compare_exchange_strong(cur, marked_node_ptr(pos.pNext), memory_model::memory_order_acquire, atomics::memory_order_relaxed )) {
if ( nMask == erase_mask )
link_to_remove_chain( pos, pos.pCur );
}
return insert_at( m_pHead, val, f );
}
- /// Ensures that the \p item exists in the list
+ /// Updates the item
/**
The operation performs inserting or changing data with lock-free manner.
- If the item \p val not found in the list, then \p val is inserted into the list.
+ If the item \p val not found in the list, then \p val is inserted into the list
+ iff \p bAllowInsert is \p true.
Otherwise, the functor \p func is called with item found.
The functor signature is:
\code
with arguments:
- \p bNew - \p true if the item has been inserted, \p false otherwise
- \p item - item of the list
- - \p val - argument \p val passed into the \p ensure function
+ - \p val - argument \p val passed into the \p update() function
If new item has been inserted (i.e. \p bNew is \p true) then \p item and \p val arguments
refer to the same thing.
The functor may change non-key fields of the \p item; however, \p func must guarantee
that during changing no any other modifications could be made on this item by concurrent threads.
- Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
- \p second is true if new item has been added or \p false if the item with \p key
+ Returns <tt> std::pair<bool, bool> </tt> where \p first is \p true if operation is successfull,
+ \p second is \p true if new item has been added or \p false if the item with \p key
already is in the list.
The function makes RCU lock internally.
@warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
*/
template <typename Func>
+ std::pair<bool, bool> update( value_type& val, Func func, bool bAllowInsert = true )
+ {
+ return update_at( m_pHead, val, func, bAllowInsert );
+ }
+ //@cond
+ template <typename Func>
+ CDS_DEPRECATED("ensure() is deprecated, use update()")
std::pair<bool, bool> ensure( value_type& val, Func func )
{
- return ensure_at( m_pHead, val, func );
+ return update( val, func, true );
}
/// Unlinks the item \p val from the list
@note The function does NOT dispose the item found. It just unlinks the item from the list
and returns a pointer to item found.
- You shouldn't lock RCU before calling this function, and you should manually release
- \p dest exempt pointer outside the RCU lock before reusing the pointer.
+ You shouldn't lock RCU for current thread before calling this function, and you should manually release
+ \p dest exempt pointer outside the RCU lock before reusing it.
\code
#include <cds/urcu/general_buffered.h>
/// Finds \p key using \p pred predicate for searching
/**
- The function is an analog of \ref cds_intrusive_MichaelList_rcu_find_func "find(Q&, Func)"
+ The function is an analog of \p find(Q&, Func)
but \p pred is used for key comparing.
\p Less functor has the interface like \p std::less.
\p pred must imply the same element order as the comparator used for building the list.
}
//@endcond
- /// Finds \p key
- /** \anchor cds_intrusive_MichaelList_rcu_find_val
+ /// Checks whether the list contains \p key
+ /**
The function searches the item with key equal to \p key
- and returns \p true if \p val found or \p false otherwise.
+ and returns \p true if it is found, and \p false otherwise.
*/
template <typename Q>
- bool find( Q const& key )
+ bool contains( Q const& key )
{
return find_at( m_pHead, key, key_comparator() );
}
+ //@cond
+ template <typename Q>
+ CDS_DEPRECATED("deprecated, use contains()")
+ bool find( Q const& key )
+ {
+ return contains( key );
+ }
+ //@endcond
- /// Finds \p key using \p pred predicate for searching
+ /// Checks whether the map contains \p key using \p pred predicate for searching
/**
- The function is an analog of \ref cds_intrusive_MichaelList_rcu_find_val "find(Q const&)"
- but \p pred is used for key comparing.
+ The function is an analog of <tt>contains( key )</tt> but \p pred is used for key comparing.
\p Less functor has the interface like \p std::less.
- \p pred must imply the same element order as the comparator used for building the list.
+ \p Less must imply the same element order as the comparator used for building the list.
*/
template <typename Q, typename Less>
- bool find_with( Q const& key, Less pred )
+ bool contains( Q const& key, Less pred )
{
CDS_UNUSED( pred );
return find_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>() );
}
+ //@cond
+ template <typename Q, typename Less>
+ CDS_DEPRECATED("deprecated, use contains()")
+ bool find_with( Q const& key, Less pred )
+ {
+ return contains( key, pred );
+ }
+ //@endcond
/// Finds \p key and return the item found
/** \anchor cds_intrusive_MichaelList_rcu_get
The function searches the item with key equal to \p key and returns the pointer to item found.
- If \p key is not found it returns \p nullptr.
+ If \p key is not found it returns empty \p raw_ptr object.
Note the compare functor should accept a parameter of type \p Q that can be not the same as \p value_type.
typedef cds::intrusive::MichaelList< cds::urcu::gc< cds::urcu::general_buffered<> >, foo, my_traits > ord_list;
ord_list theList;
// ...
+ typename ord_list::raw_ptr rp;
{
// Lock RCU
ord_list::rcu_lock lock;
- foo * pVal = theList.get( 5 );
- if ( pVal ) {
- // Deal with pVal
+ rp = theList.get( 5 );
+ if ( rp ) {
+ // Deal with rp
//...
}
// Unlock RCU by rcu_lock destructor
- // pVal can be retired by disposer at any time after RCU has been unlocked
+ // Node owned by rp can be retired by disposer at any time after RCU has been unlocked
}
+ // You can manually release rp after RCU-locked section
+ rp.release();
\endcode
*/
template <typename Q>
- value_type * get( Q const& key )
+ raw_ptr get( Q const& key )
{
return get_at( m_pHead, key, key_comparator());
}
\p pred must imply the same element order as the comparator used for building the list.
*/
template <typename Q, typename Less>
- value_type * get_with( Q const& key, Less pred )
+ raw_ptr get_with( Q const& key, Less pred )
{
CDS_UNUSED( pred );
return get_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>());
}
template <typename Func>
- std::pair<iterator, bool> ensure_at_( atomic_node_ptr& refHead, value_type& val, Func func )
+ std::pair<iterator, bool> update_at_( atomic_node_ptr& refHead, value_type& val, Func func, bool bInsert )
{
position pos( refHead );
{
rcu_lock l;
- return ensure_at_locked( pos, val, func );
+ return update_at_locked( pos, val, func, bInsert );
}
}
template <typename Func>
- std::pair<bool, bool> ensure_at( atomic_node_ptr& refHead, value_type& val, Func func )
+ std::pair<bool, bool> update_at( atomic_node_ptr& refHead, value_type& val, Func func, bool bInsert )
{
position pos( refHead );
{
rcu_lock l;
- std::pair<iterator, bool> ret = ensure_at_locked( pos, val, func );
+ std::pair<iterator, bool> ret = update_at_locked( pos, val, func, bInsert );
return std::make_pair( ret.first != end(), ret.second );
}
}
back_off bkoff;
check_deadlock_policy::check();
+ node_type * pDel;
for (;;) {
{
rcu_lock l;
if ( !search( pos.refHead, val, pos, cmp ) )
return false;
+ // store pCur since it may be changed by unlink_node() slow path
+ pDel = pos.pCur;
if ( !unlink_node( pos, erase_mask )) {
bkoff();
continue;
}
}
-
- f( *node_traits::to_value_ptr( *pos.pCur ) );
+ assert( pDel );
+ f( *node_traits::to_value_ptr( pDel ) );
--m_ItemCounter;
return true;
}
back_off bkoff;
assert( !gc::is_locked() ) ; // RCU must not be locked!!!
+ node_type * pExtracted;
{
rcu_lock l;
for (;;) {
if ( !search( refHead, val, pos, cmp ) )
return nullptr;
+ // store pCur since it may be changed by unlink_node() slow path
+ pExtracted = pos.pCur;
if ( !unlink_node( pos, extract_mask )) {
bkoff();
continue;
}
--m_ItemCounter;
- return node_traits::to_value_ptr( pos.pCur );
+ value_type * pRet = node_traits::to_value_ptr( pExtracted );
+ assert( pExtracted->m_pDelChain == nullptr );
+ return pRet;
}
}
}
}
template <typename Q, typename Compare>
- value_type * get_at( atomic_node_ptr& refHead, Q const& val, Compare cmp )
+ raw_ptr get_at( atomic_node_ptr& refHead, Q const& val, Compare cmp )
{
- value_type * pFound = nullptr;
- return find_at( refHead, val, cmp,
- [&pFound](value_type& found, Q const& ) { pFound = &found; } )
- ? pFound : nullptr;
+ // RCU should be locked!
+ assert(gc::is_locked() );
+
+ position pos( refHead );
+
+ if ( search( refHead, val, pos, cmp ))
+ return raw_ptr( node_traits::to_value_ptr( pos.pCur ), raw_ptr_disposer( pos ));
+ return raw_ptr( raw_ptr_disposer( pos ));
}
//@endcond
pNext = pCur->m_pNext.load(memory_model::memory_order_acquire);
- if ( pPrev->load(memory_model::memory_order_relaxed) != pCur
- || pNext != pCur->m_pNext.load(memory_model::memory_order_relaxed))
+ if ( pPrev->load(memory_model::memory_order_acquire) != pCur
+ || pNext != pCur->m_pNext.load(memory_model::memory_order_acquire))
{
bkoff();
goto try_again;
}
template <typename Func>
- std::pair<iterator, bool> ensure_at_locked( position& pos, value_type& val, Func func )
+ std::pair<iterator, bool> update_at_locked( position& pos, value_type& val, Func func, bool bInsert )
{
// RCU lock should be locked!!!
assert( gc::is_locked() );
return std::make_pair( iterator( pos.pCur ), false );
}
else {
+ if ( !bInsert )
+ return std::make_pair( end(), false );
+
link_checker::is_empty( node_traits::to_node_ptr( val ) );
if ( link_node( node_traits::to_node_ptr( val ), pos ) ) {
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