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library/cache/memcache/memcache.go

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+package memcache
+
+import (
+	"context"
+)
+
+// Error represents an error returned in a command reply.
+type Error string
+
+func (err Error) Error() string { return string(err) }
+
+const (
+	// Flag, 15(encoding) bit+ 17(compress) bit
+
+	// FlagRAW default flag.
+	FlagRAW = uint32(0)
+	// FlagGOB gob encoding.
+	FlagGOB = uint32(1) << 0
+	// FlagJSON json encoding.
+	FlagJSON = uint32(1) << 1
+	// FlagProtobuf protobuf
+	FlagProtobuf = uint32(1) << 2
+
+	_flagEncoding = uint32(0xFFFF8000)
+
+	// FlagGzip gzip compress.
+	FlagGzip = uint32(1) << 15
+
+	// left mv 31??? not work!!!
+	flagLargeValue = uint32(1) << 30
+)
+
+// Item is an reply to be got or stored in a memcached server.
+type Item struct {
+	// Key is the Item's key (250 bytes maximum).
+	Key string
+
+	// Value is the Item's value.
+	Value []byte
+
+	// Object is the Item's object for use codec.
+	Object interface{}
+
+	// Flags are server-opaque flags whose semantics are entirely
+	// up to the app.
+	Flags uint32
+
+	// Expiration is the cache expiration time, in seconds: either a relative
+	// time from now (up to 1 month), or an absolute Unix epoch time.
+	// Zero means the Item has no expiration time.
+	Expiration int32
+
+	// Compare and swap ID.
+	cas uint64
+}
+
+// Conn represents a connection to a Memcache server.
+// Command Reference: https://github.com/memcached/memcached/wiki/Commands
+type Conn interface {
+	// Close closes the connection.
+	Close() error
+
+	// Err returns a non-nil value if the connection is broken. The returned
+	// value is either the first non-nil value returned from the underlying
+	// network connection or a protocol parsing error. Applications should
+	// close broken connections.
+	Err() error
+
+	// Add writes the given item, if no value already exists for its key.
+	// ErrNotStored is returned if that condition is not met.
+	Add(item *Item) error
+
+	// Set writes the given item, unconditionally.
+	Set(item *Item) error
+
+	// Replace writes the given item, but only if the server *does* already
+	// hold data for this key.
+	Replace(item *Item) error
+
+	// Get sends a command to the server for gets data.
+	Get(key string) (*Item, error)
+
+	// GetMulti is a batch version of Get. The returned map from keys to items
+	// may have fewer elements than the input slice, due to memcache cache
+	// misses. Each key must be at most 250 bytes in length.
+	// If no error is returned, the returned map will also be non-nil.
+	GetMulti(keys []string) (map[string]*Item, error)
+
+	// Delete deletes the item with the provided key.
+	// The error ErrCacheMiss is returned if the item didn't already exist in
+	// the cache.
+	Delete(key string) error
+
+	// Increment atomically increments key by delta. The return value is the
+	// new value after being incremented or an error. If the value didn't exist
+	// in memcached the error is ErrCacheMiss. The value in memcached must be
+	// an decimal number, or an error will be returned.
+	// On 64-bit overflow, the new value wraps around.
+	Increment(key string, delta uint64) (newValue uint64, err error)
+
+	// Decrement atomically decrements key by delta. The return value is the
+	// new value after being decremented or an error. If the value didn't exist
+	// in memcached the error is ErrCacheMiss. The value in memcached must be
+	// an decimal number, or an error will be returned. On underflow, the new
+	// value is capped at zero and does not wrap around.
+	Decrement(key string, delta uint64) (newValue uint64, err error)
+
+	// CompareAndSwap writes the given item that was previously returned by
+	// Get, if the value was neither modified or evicted between the Get and
+	// the CompareAndSwap calls. The item's Key should not change between calls
+	// but all other item fields may differ. ErrCASConflict is returned if the
+	// value was modified in between the calls.
+	// ErrNotStored is returned if the value was evicted in between the calls.
+	CompareAndSwap(item *Item) error
+
+	// Touch updates the expiry for the given key. The seconds parameter is
+	// either a Unix timestamp or, if seconds is less than 1 month, the number
+	// of seconds into the future at which time the item will expire.
+	//ErrCacheMiss is returned if the key is not in the cache. The key must be
+	// at most 250 bytes in length.
+	Touch(key string, seconds int32) (err error)
+
+	// Scan converts value read from the memcache into the following
+	// common Go types and special types:
+	//
+	//    *string
+	//    *[]byte
+	//    *interface{}
+	//
+	Scan(item *Item, v interface{}) (err error)
+
+	// WithContext return a Conn with its context changed to ctx
+	// the context controls the entire lifetime of Conn before you change it
+	// NOTE: this method is not thread-safe
+	WithContext(ctx context.Context) Conn
+}