cachestorage.go

package main

const (
	Ok = iota
	KeyAlreadyInUse
	KeyNotFound
	IllegalParameter
)

type ErrorCode uint

type StorageEntry struct {
	exptime    uint32
	flags      uint32
	bytes      uint32
	cas_unique uint64
	content    []byte
}

type CacheStorageFactory func() CacheStorage

type CacheStorage interface {

	// Store this data.
	Set(key string, flags uint32, exptime uint32, bytes uint32, content []byte) (previous *StorageEntry, result *StorageEntry)

	// Store this data, but only if the server *doesn't* already hold data for this key
	Add(key string, flags uint32, exptime uint32, bytes uint32, content []byte) (err ErrorCode, result *StorageEntry)

	// Store this data, but only if the server *does* already hold data for this key
	Replace(key string, flags uint32, exptime uint32, bytes uint32, content []byte) (err ErrorCode, previous *StorageEntry, result *StorageEntry)

	// Add this data to an existing key after existing data
	Append(key string, bytes uint32, content []byte) (err ErrorCode, previous *StorageEntry, result *StorageEntry)

	// Add this data to an existing key before existing data
	Prepend(key string, bytes uint32, content []byte) (err ErrorCode, previous *StorageEntry, result *StorageEntry)

	// Check and set (CAS) operation which means "store this data but
	// only if no one else has updated since I last fetched it"
	Cas(key string, flags uint32, exptime uint32, bytes uint32, cas_unique uint64, content []byte) (err ErrorCode, previous *StorageEntry, result *StorageEntry)

	// Retrieve the stored data for a given key 
	Get(key string) (err ErrorCode, result *StorageEntry)

	// Delete the stored data for a given key 
	Delete(key string) (err ErrorCode, deleted *StorageEntry)

	// Change data for some item in-place, incrementing or decrementing it.
	// The data for the item is treated as decimal representation of a 64-bit unsigned integer.  
	// If the current data value does not conform to such a representation, returns an error.
	// Also, the item must already exist for incr/decr to work; these commands won't pretend
	// that a non-existent key exists with value 0; instead, they will fail. 
	Incr(key string, value uint64, incr bool) (err ErrorCode, previous *StorageEntry, result *StorageEntry)

	Expire(key string, check bool)
}