exp: golang.org/x/exp/sumdb/internal/tkv Index | Files | Directories

package tkv

import "golang.org/x/exp/sumdb/internal/tkv"

Package tkv defines a simple interface to a transactional key-value storage system.

Index

Package Files

tkv.go

type Storage Uses

type Storage interface {
    // ReadOnly runs f in a read-only transaction.
    // It is equivalent to ReadWrite except that the
    // transaction's BufferWrite method will fail unconditionally.
    // (The implementation may be able to optimize the
    // transaction if it knows at the start that no writes will happen.)
    ReadOnly(ctx context.Context, f func(context.Context, Transaction) error) error

    // ReadWrite runs f in a read-write transaction.
    // If f returns an error, the transaction aborts and returns that error.
    // If f returns nil, the transaction attempts to commit and then then return nil.
    // Otherwise it tries again. Note that f may be called multiple times and that
    // the result only describes the effect of the final call to f.
    // The caller must take care not to use any state computed during
    // earlier calls to f, or even the last call to f when an error is returned.
    ReadWrite(ctx context.Context, f func(context.Context, Transaction) error) error
}

A Storage is a transaction key-value storage system.

type Transaction Uses

type Transaction interface {
    // ReadValue reads the value associated with a single key.
    // If there is no value associated with that key, ReadKey returns an empty value.
    // An error is only returned for problems accessing the storage.
    ReadValue(ctx context.Context, key string) (value string, err error)

    // ReadValues reads the values associated with the given keys.
    // If there is no value stored for a given key, ReadValues returns an empty value for that key.
    // An error is only returned for problems accessing the storage.
    ReadValues(ctx context.Context, keys []string) (values []string, err error)

    // BufferWrites buffers the given writes,
    // to be applied at the end of the transaction.
    // BufferWrites panics if this is a ReadOnly transaction.
    // It returns an error if it detects any other problems.
    // The behavior of multiple writes buffered using the same key
    // is undefined: it may return an error or not.
    BufferWrites(writes []Write) error
}

A Transaction provides read and write operations within a transaction, as executed by Storage's ReadOnly or ReadWrite methods.

type Write Uses

type Write struct {
    Key   string
    Value string
}

A Write is a single change to be applied at the end of a read-write transaction. A Write with an empty value deletes the value associated with the given key.

Directories

PathSynopsis
tkvtestPackage tkvtest contains a test harness for testing tkv.Storage implementations.

Package tkv imports 1 packages (graph) and is imported by 1 packages. Updated 2019-08-02. Refresh now. Tools for package owners.