forked from mirrors/gotosocial
64 lines
1.5 KiB
Go
64 lines
1.5 KiB
Go
package kv
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import (
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"git.iim.gay/grufwub/go-errors"
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"git.iim.gay/grufwub/go-store/storage"
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)
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var ErrIteratorClosed = errors.Define("store/kv: iterator closed")
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// KVIterator provides a read-only iterator to all the key-value
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// pairs in a KVStore. While the iterator is open the store is read
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// locked, you MUST release the iterator when you are finished with
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// it.
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//
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// Please note:
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// - individual iterators are NOT concurrency safe, though it is safe to
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// have multiple iterators running concurrently
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type KVIterator struct {
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store *KVStore // store is the linked KVStore
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entries []storage.StorageEntry
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index int
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key string
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onClose func()
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}
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// Next attempts to set the next key-value pair, the
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// return value is if there was another pair remaining
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func (i *KVIterator) Next() bool {
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next := i.index + 1
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if next >= len(i.entries) {
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i.key = ""
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return false
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}
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i.key = i.entries[next].Key()
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i.index = next
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return true
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}
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// Key returns the next key from the store
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func (i *KVIterator) Key() string {
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return i.key
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}
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// Release releases the KVIterator and KVStore's read lock
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func (i *KVIterator) Release() {
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// Reset key, path, entries
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i.store = nil
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i.key = ""
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i.entries = nil
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// Perform requested callback
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i.onClose()
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}
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// Value returns the next value from the KVStore
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func (i *KVIterator) Value() ([]byte, error) {
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// Check store isn't closed
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if i.store == nil {
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return nil, ErrIteratorClosed
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}
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// Attempt to fetch from store
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return i.store.get(i.key)
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}
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