memgraph/include/storage/record_accessor.hpp
2016-08-30 08:53:02 +01:00

155 lines
4.0 KiB
C++

#pragma once
#include "database/db_transaction.hpp"
#include "mvcc/version_list.hpp"
#include "storage/indexes/index_record.hpp"
#include "storage/indexes/index_update.hpp"
#include "storage/model/properties/properties.hpp"
#include "storage/model/properties/property.hpp"
#include "storage/model/properties/property_family.hpp"
#include "transactions/transaction.hpp"
template <class TG, class Derived>
class RecordAccessor
{
friend DbAccessor;
using vlist_t = typename TG::vlist_t;
using T = typename TG::record_t;
public:
RecordAccessor(vlist_t *vlist, DbTransaction &db) : vlist(vlist), db(db)
{
assert(vlist != nullptr);
}
RecordAccessor(T *t, vlist_t *vlist, DbTransaction &db)
: record(t), vlist(vlist), db(db)
{
assert(record != nullptr);
assert(vlist != nullptr);
}
RecordAccessor(RecordAccessor const &other)
: record(other.record), vlist(other.vlist), db(other.db)
{
}
RecordAccessor(RecordAccessor &&other)
: record(other.record), vlist(other.vlist), db(other.db)
{
}
bool empty() const { return record == nullptr; }
// Fills accessor and returns true if there is valid data for current
// transaction false otherwise.
bool fill() const
{
const_cast<RecordAccessor *>(this)->record = vlist->find(db.trans);
return record != nullptr;
}
const Id &id() const { return vlist->id; }
// TODO: Test this
Derived update() const
{
assert(!empty());
if (record->is_visible_write(db.trans)) {
// TODO: VALIDATE THIS BRANCH. THEN ONLY THIS TRANSACTION CAN SEE
// THIS DATA WHICH MEENS THAT IT CAN CHANGE IT.
return Derived(record, vlist, db);
} else {
auto new_record = vlist->update(db.trans);
// TODO: Validate that update of record in this accessor is correct.
const_cast<RecordAccessor *>(this)->record = new_record;
// Add record to update index.
db.to_update_index<TG>(vlist, new_record);
return Derived(new_record, vlist, db);
}
}
const Property &at(PropertyFamily<TG> &key) const
{
return properties().at(key);
}
const Property &at(prop_key_t<TG> &key) const
{
return properties().at(key);
}
template <class V>
OptionPtr<V> at(type_key_t<TG, V> &key) const
{
return properties().template at<V>(key);
}
template <class V, class... Args>
void set(type_key_t<TG, V> &key, Args &&... args)
{
properties().template set<V>(key, std::forward<Args>(args)...);
}
void set(prop_key_t<TG> &key, Property::sptr value)
{
properties().set(key, std::move(value));
}
void clear(prop_key_t<TG> &key) { properties().clear(key); }
void clear(PropertyFamily<TG> &key) { properties().clear(key); }
template <class Handler>
void accept(Handler &handler) const
{
properties().template accept<Handler>(handler);
}
Properties<TG> &properties() const { return record->data.props; }
explicit operator bool() const { return record != nullptr; }
T const *operator->() const { return record; }
T *operator->() { return record; }
RecordAccessor &operator=(const RecordAccessor &other)
{
record = other.record;
vlist_t *&vl = const_cast<vlist_t *&>(vlist);
vl = other.vlist;
return *this;
}
RecordAccessor &operator=(RecordAccessor &&other)
{
record = other.record;
vlist_t *&vl = const_cast<vlist_t *&>(vlist);
vl = other.vlist;
return *this;
}
// Assumes same transaction
friend bool operator==(const RecordAccessor &a, const RecordAccessor &b)
{
return a.vlist == b.vlist;
}
// Assumes same transaction
friend bool operator!=(const RecordAccessor &a, const RecordAccessor &b)
{
return !(a == b);
}
protected:
void remove() const;
T *record{nullptr};
vlist_t *const vlist;
DbTransaction &db;
};