/
engine_delete.go
165 lines (129 loc) · 4.13 KB
/
engine_delete.go
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package leveldb_core
import (
"encoding/binary"
"fmt"
"github.com/Gophercraft/phylactery/database/query"
"github.com/syndtr/goleveldb/leveldb"
"github.com/syndtr/goleveldb/leveldb/opt"
"github.com/syndtr/goleveldb/leveldb/util"
)
// wipes out an entire database's content - no going back from this
func (engine *engine) mass_delete(table_id int32) (deleted uint64, err error) {
var snapshot *leveldb.Snapshot
snapshot, err = engine.db.GetSnapshot()
if err != nil {
return
}
var table *table
table, err = engine.get_table(table_id)
if err != nil {
return
}
table.lock_info()
// Start reading at the row sector, but stop reading at the start of a new table.
var mass_range util.Range
mass_range.Start = make_record_sector_key(table_id, 0)
mass_range.Limit = make([]byte, 17)
binary.LittleEndian.PutUint32(mass_range.Limit[0:4], uint32(table_id+1))
mass_range.Limit[4] = uint8(key_type_table_info)
var read_options opt.ReadOptions
var delete_options opt.WriteOptions
iter := snapshot.NewIterator(&mass_range, &read_options)
for iter.Next() {
key := iter.Key()
key_table := int32(binary.LittleEndian.Uint32(key[0:4]))
if key_table != table_id {
iter.Release()
err = fmt.Errorf("invalid table ID (%d) in iterator. Iterator sorting is messed up", key_table)
return
}
key_type := key_type(key[4])
switch key_type {
case key_type_table_record:
deleted++
engine.db.Delete(key, &delete_options)
case key_type_table_column_exclusive_index:
engine.db.Delete(key, &delete_options)
case key_type_table_column_repeatable_index:
engine.db.Delete(key, &delete_options)
}
}
table.info.rows -= deleted
engine.put_table_info(table_id)
table.unlock_info()
iter.Release()
snapshot.Release()
return
}
func (engine *engine) delete_specific_records(table_id int32, delete_list []uint64) (deleted uint64, err error) {
sort_deletelist(delete_list)
var snapshot *leveldb.Snapshot
snapshot, err = engine.db.GetSnapshot()
if err != nil {
return
}
var table *table
table, err = engine.get_table(table_id)
if err != nil {
return
}
table.lock_info()
// Start reading at the row sector, but stop reading at the start of a new table.
var mass_range util.Range
mass_range.Start = make_record_sector_key(table_id, 0)
mass_range.Limit = make([]byte, 17)
binary.LittleEndian.PutUint32(mass_range.Limit[0:4], uint32(table_id+1))
mass_range.Limit[4] = uint8(key_type_table_info)
var read_options opt.ReadOptions
var delete_options opt.WriteOptions
iter := snapshot.NewIterator(&mass_range, &read_options)
for iter.Next() {
key := iter.Key()
value := iter.Value()
key_table := int32(binary.LittleEndian.Uint32(key[0:4]))
if key_table != table_id {
iter.Release()
err = fmt.Errorf("invalid table ID (%d) in iterator. Iterator sorting is messed up", key_table)
return
}
key_type := key_type(key[4])
switch key_type {
case key_type_table_record:
key_record_ID := binary.LittleEndian.Uint64(key[5:13])
should_delete := found_in_deletelist(delete_list, key_record_ID)
if should_delete {
engine.db.Delete(key, &delete_options)
deleted++
}
case key_type_table_column_exclusive_index, key_type_table_column_repeatable_index:
value_record_ID := binary.LittleEndian.Uint64(value)
should_delete := found_in_deletelist(delete_list, value_record_ID)
if should_delete {
engine.db.Delete(key, &delete_options)
}
}
}
table.info.rows -= deleted
engine.put_table_info(table_id)
table.unlock_info()
iter.Release()
snapshot.Release()
return
}
func (engine *engine) Delete(table_id int32, expr *query.Expression) (deleted uint64, err error) {
if len(expr.Conditions) == 0 {
return engine.mass_delete(table_id)
}
var snap *leveldb.Snapshot
snap, err = engine.db.GetSnapshot()
if err != nil {
return
}
var record_IDs []uint64
_, record_IDs, err = engine.presort_query_full(snap, table_id, expr)
if err != nil {
return
}
snap.Release()
return engine.delete_specific_records(table_id, record_IDs)
}