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Added the insert operation #33

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Added the insert operation #33

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72 changes: 72 additions & 0 deletions junction/ConcurrentMap_Grampa.h
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Original file line number Diff line number Diff line change
Expand Up @@ -403,6 +403,73 @@ class ConcurrentMap_Grampa {
}
}

bool putValueIfNotExists(Value desired) {
TURF_ASSERT(desired != Value(ValueTraits::NullValue));
TURF_ASSERT(desired != Value(ValueTraits::Redirect));
TURF_ASSERT(m_cell); // Cell must have been found or inserted
TURF_TRACE(ConcurrentMap_Grampa, 14, "[Mutator::exchangeValue] called", uptr(m_table), uptr(m_value));
for (;;) {
Value oldValue = m_value;
if(oldValue == Value(ValueTraits::NullValue)) {
if (m_cell->value.compareExchangeStrong(m_value, desired, turf::ConsumeRelease)) {
// Exchange was successful. Return previous value.
TURF_TRACE(ConcurrentMap_Grampa, 15, "[Mutator::exchangeValue] exchanged Value", uptr(m_value),
uptr(desired));
m_value = desired; // Leave the mutator in a valid state
return true;
}
} else {
return false;
}
// The CAS failed and m_value has been updated with the latest value.
if (m_value != Value(ValueTraits::Redirect)) {
TURF_TRACE(ConcurrentMap_Grampa, 16, "[Mutator::exchangeValue] detected race to write value", uptr(m_table),
uptr(m_value));
if (m_value != Value(ValueTraits::NullValue)) {
TURF_TRACE(ConcurrentMap_Grampa, 17, "[Mutator::exchangeValue] racing write inserted new value",
uptr(m_table), uptr(m_value));
}
// There was a racing write (or erase) to this cell.
return false;
}
// We've encountered a Redirect value. Help finish the migration.
TURF_TRACE(ConcurrentMap_Grampa, 18, "[Mutator::exchangeValue] was redirected", uptr(m_table), uptr(m_value));
Hash hash = m_cell->hash.load(turf::Relaxed);
for (;;) {
// Help complete the migration.
m_table->jobCoordinator.participate();
// Try again in the latest table.
// FIXME: locateTable() could return false if the map is concurrently cleared (m_root set to 0).
// This is not concern yet since clear() is not implemented.
bool exists = m_map.locateTable(m_table, m_sizeMask, hash);
TURF_ASSERT(exists);
TURF_UNUSED(exists);
m_value = Value(ValueTraits::NullValue);
ureg overflowIdx;
switch (Details::insertOrFind(hash, m_table, m_sizeMask, m_cell, overflowIdx)) { // Modifies m_cell
case Details::InsertResult_AlreadyFound:
m_value = m_cell->value.load(turf::Consume);
if (m_value == Value(ValueTraits::Redirect)) {
TURF_TRACE(ConcurrentMap_Grampa, 19, "[Mutator::exchangeValue] was re-redirected", uptr(m_table),
uptr(m_value));
break;
}
goto breakOuter;
case Details::InsertResult_InsertedNew:
goto breakOuter;
case Details::InsertResult_Overflow:
TURF_TRACE(ConcurrentMap_Grampa, 20, "[Mutator::exchangeValue] overflow after redirect", uptr(m_table),
overflowIdx);
Details::beginTableMigration(m_map, m_table, overflowIdx);
break;
}
// We were redirected... again
}
breakOuter:;
// Try again in the new table.
}
}

void assignValue(Value desired) {
exchangeValue(desired);
}
Expand Down Expand Up @@ -483,6 +550,11 @@ class ConcurrentMap_Grampa {
}
}

bool insert(Key key, Value desired) {
Mutator iter(*this, key);
return iter.putValueIfNotExists(desired);
}

Value assign(Key key, Value desired) {
Mutator iter(*this, key);
return iter.exchangeValue(desired);
Expand Down