94 lines
1.9 KiB
Go
94 lines
1.9 KiB
Go
package ramdb
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import "github.com/google/btree"
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// Get validates that the table and index for the given column exists and searches for the given key in the tree.
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func (t *table) Get(column, key string) (r *record, err error) {
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if !t.exists {
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return nil, ErrNoTable
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}
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if !t.HasIndex(column) {
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return nil, ErrNoIndex
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}
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return t.keyLookup(key, t.indexes[column])
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}
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// keyLookup tries to find the given key in the tree. It returns ErrNoRecord if not found.
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func (t *table) keyLookup(key string, index *index) (r *record, err error) {
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item := &record{id: keyHash(key)}
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result := index.tree.Get(item)
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if result == nil {
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return nil, ErrNoRecord
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}
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return result.(*record), nil
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}
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// Select returns all of the records in the database sorted in ascending order by id.
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func (t *table) Select(column string) (rr []*record, err error) {
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if !t.exists {
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return nil, ErrNoTable
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}
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if !t.HasIndex(column) {
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return nil, ErrNoIndex
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}
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t.indexes[column].tree.Ascend(func(item btree.Item) bool {
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r := item.(*record)
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rr = append(rr, r)
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return true
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})
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return
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}
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// Insert adds the record to the database. It returns ErrRecordExists if the record already exists. Insert is thread safe.
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func (t *table) Insert(r *record) error {
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if !t.exists {
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return ErrNoTable
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}
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if !t.HasIndex(r.keyColumn) {
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return ErrNoIndex
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}
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index := t.indexes[r.keyColumn]
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if has := index.tree.Has(r); has {
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return ErrRecordExists
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}
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t.mutex.Lock()
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defer t.mutex.Unlock()
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index.tree.ReplaceOrInsert(r)
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return nil
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}
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// Delete removes the item from the database. It returns ErrNoRecord if the record does not exist and ErrNotDeleted if the removal fails. Delete is thread safe.
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func (t *table) Delete(r *record) error {
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if !t.exists {
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return ErrNoTable
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}
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if !t.HasIndex(r.keyColumn) {
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return ErrNoIndex
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}
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index := t.indexes[r.keyColumn]
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if has := index.tree.Has(r); !has {
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return ErrNoRecord
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}
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t.mutex.Lock()
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defer t.mutex.Unlock()
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index.tree.Delete(r)
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return nil
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}
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