Add database iteration to restricted backend

Needed for cardinal state dump
This commit is contained in:
Austin Roberts 2021-09-23 16:47:38 -05:00
parent 5f304c2de3
commit 92f38f719c

View File

@ -123,5 +123,51 @@ type Database interface {
Writer
Stater
Compacter
Iteratee
io.Closer
}
// Iterator iterates over a database's key/value pairs in ascending key order.
//
// When it encounters an error any seek will return false and will yield no key/
// value pairs. The error can be queried by calling the Error method. Calling
// Release is still necessary.
//
// An iterator must be released after use, but it is not necessary to read an
// iterator until exhaustion. An iterator is not safe for concurrent use, but it
// is safe to use multiple iterators concurrently.
type Iterator interface {
// Next moves the iterator to the next key/value pair. It returns whether the
// iterator is exhausted.
Next() bool
// Error returns any accumulated error. Exhausting all the key/value pairs
// is not considered to be an error.
Error() error
// Key returns the key of the current key/value pair, or nil if done. The caller
// should not modify the contents of the returned slice, and its contents may
// change on the next call to Next.
Key() []byte
// Value returns the value of the current key/value pair, or nil if done. The
// caller should not modify the contents of the returned slice, and its contents
// may change on the next call to Next.
Value() []byte
// Release releases associated resources. Release should always succeed and can
// be called multiple times without causing error.
Release()
}
// Iteratee wraps the NewIterator methods of a backing data store.
type Iteratee interface {
// NewIterator creates a binary-alphabetical iterator over a subset
// of database content with a particular key prefix, starting at a particular
// initial key (or after, if it does not exist).
//
// Note: This method assumes that the prefix is NOT part of the start, so there's
// no need for the caller to prepend the prefix to the start
NewIterator(prefix []byte, start []byte) Iterator
}