diff options
Diffstat (limited to 'vendor/google.golang.org/appengine/memcache/memcache.go')
| -rw-r--r-- | vendor/google.golang.org/appengine/memcache/memcache.go | 526 |
1 files changed, 0 insertions, 526 deletions
diff --git a/vendor/google.golang.org/appengine/memcache/memcache.go b/vendor/google.golang.org/appengine/memcache/memcache.go deleted file mode 100644 index d8eed4be7..000000000 --- a/vendor/google.golang.org/appengine/memcache/memcache.go +++ /dev/null @@ -1,526 +0,0 @@ -// Copyright 2011 Google Inc. All rights reserved. -// Use of this source code is governed by the Apache 2.0 -// license that can be found in the LICENSE file. - -// Package memcache provides a client for App Engine's distributed in-memory -// key-value store for small chunks of arbitrary data. -// -// The fundamental operations get and set items, keyed by a string. -// -// item0, err := memcache.Get(c, "key") -// if err != nil && err != memcache.ErrCacheMiss { -// return err -// } -// if err == nil { -// fmt.Fprintf(w, "memcache hit: Key=%q Val=[% x]\n", item0.Key, item0.Value) -// } else { -// fmt.Fprintf(w, "memcache miss\n") -// } -// -// and -// -// item1 := &memcache.Item{ -// Key: "foo", -// Value: []byte("bar"), -// } -// if err := memcache.Set(c, item1); err != nil { -// return err -// } -package memcache // import "google.golang.org/appengine/memcache" - -import ( - "bytes" - "encoding/gob" - "encoding/json" - "errors" - "time" - - "github.com/golang/protobuf/proto" - "golang.org/x/net/context" - - "google.golang.org/appengine" - "google.golang.org/appengine/internal" - pb "google.golang.org/appengine/internal/memcache" -) - -var ( - // ErrCacheMiss means that an operation failed - // because the item wasn't present. - ErrCacheMiss = errors.New("memcache: cache miss") - // ErrCASConflict means that a CompareAndSwap call failed due to the - // cached value being modified between the Get and the CompareAndSwap. - // If the cached value was simply evicted rather than replaced, - // ErrNotStored will be returned instead. - ErrCASConflict = errors.New("memcache: compare-and-swap conflict") - // ErrNoStats means that no statistics were available. - ErrNoStats = errors.New("memcache: no statistics available") - // ErrNotStored means that a conditional write operation (i.e. Add or - // CompareAndSwap) failed because the condition was not satisfied. - ErrNotStored = errors.New("memcache: item not stored") - // ErrServerError means that a server error occurred. - ErrServerError = errors.New("memcache: server error") -) - -// Item is the unit of memcache gets and sets. -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 value for use with a Codec. - Object interface{} - // Flags are server-opaque flags whose semantics are entirely up to the - // App Engine app. - Flags uint32 - // Expiration is the maximum duration that the item will stay - // in the cache. - // The zero value means the Item has no expiration time. - // Subsecond precision is ignored. - // This is not set when getting items. - Expiration time.Duration - // casID is a client-opaque value used for compare-and-swap operations. - // Zero means that compare-and-swap is not used. - casID uint64 -} - -const ( - secondsIn30Years = 60 * 60 * 24 * 365 * 30 // from memcache server code - thirtyYears = time.Duration(secondsIn30Years) * time.Second -) - -// protoToItem converts a protocol buffer item to a Go struct. -func protoToItem(p *pb.MemcacheGetResponse_Item) *Item { - return &Item{ - Key: string(p.Key), - Value: p.Value, - Flags: p.GetFlags(), - casID: p.GetCasId(), - } -} - -// If err is an appengine.MultiError, return its first element. Otherwise, return err. -func singleError(err error) error { - if me, ok := err.(appengine.MultiError); ok { - return me[0] - } - return err -} - -// Get gets the item for the given key. ErrCacheMiss is returned for a memcache -// cache miss. The key must be at most 250 bytes in length. -func Get(c context.Context, key string) (*Item, error) { - m, err := GetMulti(c, []string{key}) - if err != nil { - return nil, err - } - if _, ok := m[key]; !ok { - return nil, ErrCacheMiss - } - return m[key], nil -} - -// 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. -func GetMulti(c context.Context, key []string) (map[string]*Item, error) { - if len(key) == 0 { - return nil, nil - } - keyAsBytes := make([][]byte, len(key)) - for i, k := range key { - keyAsBytes[i] = []byte(k) - } - req := &pb.MemcacheGetRequest{ - Key: keyAsBytes, - ForCas: proto.Bool(true), - } - res := &pb.MemcacheGetResponse{} - if err := internal.Call(c, "memcache", "Get", req, res); err != nil { - return nil, err - } - m := make(map[string]*Item, len(res.Item)) - for _, p := range res.Item { - t := protoToItem(p) - m[t.Key] = t - } - return m, nil -} - -// Delete deletes the item for the given key. -// ErrCacheMiss is returned if the specified item can not be found. -// The key must be at most 250 bytes in length. -func Delete(c context.Context, key string) error { - return singleError(DeleteMulti(c, []string{key})) -} - -// DeleteMulti is a batch version of Delete. -// If any keys cannot be found, an appengine.MultiError is returned. -// Each key must be at most 250 bytes in length. -func DeleteMulti(c context.Context, key []string) error { - if len(key) == 0 { - return nil - } - req := &pb.MemcacheDeleteRequest{ - Item: make([]*pb.MemcacheDeleteRequest_Item, len(key)), - } - for i, k := range key { - req.Item[i] = &pb.MemcacheDeleteRequest_Item{Key: []byte(k)} - } - res := &pb.MemcacheDeleteResponse{} - if err := internal.Call(c, "memcache", "Delete", req, res); err != nil { - return err - } - if len(res.DeleteStatus) != len(key) { - return ErrServerError - } - me, any := make(appengine.MultiError, len(key)), false - for i, s := range res.DeleteStatus { - switch s { - case pb.MemcacheDeleteResponse_DELETED: - // OK - case pb.MemcacheDeleteResponse_NOT_FOUND: - me[i] = ErrCacheMiss - any = true - default: - me[i] = ErrServerError - any = true - } - } - if any { - return me - } - return nil -} - -// Increment atomically increments the decimal value in the given key -// by delta and returns the new value. The value must fit in a uint64. -// Overflow wraps around, and underflow is capped to zero. The -// provided delta may be negative. If the key doesn't exist in -// memcache, the provided initial value is used to atomically -// populate it before the delta is applied. -// The key must be at most 250 bytes in length. -func Increment(c context.Context, key string, delta int64, initialValue uint64) (newValue uint64, err error) { - return incr(c, key, delta, &initialValue) -} - -// IncrementExisting works like Increment but assumes that the key -// already exists in memcache and doesn't take an initial value. -// IncrementExisting can save work if calculating the initial value is -// expensive. -// An error is returned if the specified item can not be found. -func IncrementExisting(c context.Context, key string, delta int64) (newValue uint64, err error) { - return incr(c, key, delta, nil) -} - -func incr(c context.Context, key string, delta int64, initialValue *uint64) (newValue uint64, err error) { - req := &pb.MemcacheIncrementRequest{ - Key: []byte(key), - InitialValue: initialValue, - } - if delta >= 0 { - req.Delta = proto.Uint64(uint64(delta)) - } else { - req.Delta = proto.Uint64(uint64(-delta)) - req.Direction = pb.MemcacheIncrementRequest_DECREMENT.Enum() - } - res := &pb.MemcacheIncrementResponse{} - err = internal.Call(c, "memcache", "Increment", req, res) - if err != nil { - return - } - if res.NewValue == nil { - return 0, ErrCacheMiss - } - return *res.NewValue, nil -} - -// set sets the given items using the given conflict resolution policy. -// appengine.MultiError may be returned. -func set(c context.Context, item []*Item, value [][]byte, policy pb.MemcacheSetRequest_SetPolicy) error { - if len(item) == 0 { - return nil - } - req := &pb.MemcacheSetRequest{ - Item: make([]*pb.MemcacheSetRequest_Item, len(item)), - } - for i, t := range item { - p := &pb.MemcacheSetRequest_Item{ - Key: []byte(t.Key), - } - if value == nil { - p.Value = t.Value - } else { - p.Value = value[i] - } - if t.Flags != 0 { - p.Flags = proto.Uint32(t.Flags) - } - if t.Expiration != 0 { - // In the .proto file, MemcacheSetRequest_Item uses a fixed32 (i.e. unsigned) - // for expiration time, while MemcacheGetRequest_Item uses int32 (i.e. signed). - // Throughout this .go file, we use int32. - // Also, in the proto, the expiration value is either a duration (in seconds) - // or an absolute Unix timestamp (in seconds), depending on whether the - // value is less than or greater than or equal to 30 years, respectively. - if t.Expiration < time.Second { - // Because an Expiration of 0 means no expiration, we take - // care here to translate an item with an expiration - // Duration between 0-1 seconds as immediately expiring - // (saying it expired a few seconds ago), rather than - // rounding it down to 0 and making it live forever. - p.ExpirationTime = proto.Uint32(uint32(time.Now().Unix()) - 5) - } else if t.Expiration >= thirtyYears { - p.ExpirationTime = proto.Uint32(uint32(time.Now().Unix()) + uint32(t.Expiration/time.Second)) - } else { - p.ExpirationTime = proto.Uint32(uint32(t.Expiration / time.Second)) - } - } - if t.casID != 0 { - p.CasId = proto.Uint64(t.casID) - p.ForCas = proto.Bool(true) - } - p.SetPolicy = policy.Enum() - req.Item[i] = p - } - res := &pb.MemcacheSetResponse{} - if err := internal.Call(c, "memcache", "Set", req, res); err != nil { - return err - } - if len(res.SetStatus) != len(item) { - return ErrServerError - } - me, any := make(appengine.MultiError, len(item)), false - for i, st := range res.SetStatus { - var err error - switch st { - case pb.MemcacheSetResponse_STORED: - // OK - case pb.MemcacheSetResponse_NOT_STORED: - err = ErrNotStored - case pb.MemcacheSetResponse_EXISTS: - err = ErrCASConflict - default: - err = ErrServerError - } - if err != nil { - me[i] = err - any = true - } - } - if any { - return me - } - return nil -} - -// Set writes the given item, unconditionally. -func Set(c context.Context, item *Item) error { - return singleError(set(c, []*Item{item}, nil, pb.MemcacheSetRequest_SET)) -} - -// SetMulti is a batch version of Set. -// appengine.MultiError may be returned. -func SetMulti(c context.Context, item []*Item) error { - return set(c, item, nil, pb.MemcacheSetRequest_SET) -} - -// Add writes the given item, if no value already exists for its key. -// ErrNotStored is returned if that condition is not met. -func Add(c context.Context, item *Item) error { - return singleError(set(c, []*Item{item}, nil, pb.MemcacheSetRequest_ADD)) -} - -// AddMulti is a batch version of Add. -// appengine.MultiError may be returned. -func AddMulti(c context.Context, item []*Item) error { - return set(c, item, nil, pb.MemcacheSetRequest_ADD) -} - -// 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. -func CompareAndSwap(c context.Context, item *Item) error { - return singleError(set(c, []*Item{item}, nil, pb.MemcacheSetRequest_CAS)) -} - -// CompareAndSwapMulti is a batch version of CompareAndSwap. -// appengine.MultiError may be returned. -func CompareAndSwapMulti(c context.Context, item []*Item) error { - return set(c, item, nil, pb.MemcacheSetRequest_CAS) -} - -// Codec represents a symmetric pair of functions that implement a codec. -// Items stored into or retrieved from memcache using a Codec have their -// values marshaled or unmarshaled. -// -// All the methods provided for Codec behave analogously to the package level -// function with same name. -type Codec struct { - Marshal func(interface{}) ([]byte, error) - Unmarshal func([]byte, interface{}) error -} - -// Get gets the item for the given key and decodes the obtained value into v. -// ErrCacheMiss is returned for a memcache cache miss. -// The key must be at most 250 bytes in length. -func (cd Codec) Get(c context.Context, key string, v interface{}) (*Item, error) { - i, err := Get(c, key) - if err != nil { - return nil, err - } - if err := cd.Unmarshal(i.Value, v); err != nil { - return nil, err - } - return i, nil -} - -func (cd Codec) set(c context.Context, items []*Item, policy pb.MemcacheSetRequest_SetPolicy) error { - var vs [][]byte - var me appengine.MultiError - for i, item := range items { - v, err := cd.Marshal(item.Object) - if err != nil { - if me == nil { - me = make(appengine.MultiError, len(items)) - } - me[i] = err - continue - } - if me == nil { - vs = append(vs, v) - } - } - if me != nil { - return me - } - - return set(c, items, vs, policy) -} - -// Set writes the given item, unconditionally. -func (cd Codec) Set(c context.Context, item *Item) error { - return singleError(cd.set(c, []*Item{item}, pb.MemcacheSetRequest_SET)) -} - -// SetMulti is a batch version of Set. -// appengine.MultiError may be returned. -func (cd Codec) SetMulti(c context.Context, items []*Item) error { - return cd.set(c, items, pb.MemcacheSetRequest_SET) -} - -// Add writes the given item, if no value already exists for its key. -// ErrNotStored is returned if that condition is not met. -func (cd Codec) Add(c context.Context, item *Item) error { - return singleError(cd.set(c, []*Item{item}, pb.MemcacheSetRequest_ADD)) -} - -// AddMulti is a batch version of Add. -// appengine.MultiError may be returned. -func (cd Codec) AddMulti(c context.Context, items []*Item) error { - return cd.set(c, items, pb.MemcacheSetRequest_ADD) -} - -// 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. -func (cd Codec) CompareAndSwap(c context.Context, item *Item) error { - return singleError(cd.set(c, []*Item{item}, pb.MemcacheSetRequest_CAS)) -} - -// CompareAndSwapMulti is a batch version of CompareAndSwap. -// appengine.MultiError may be returned. -func (cd Codec) CompareAndSwapMulti(c context.Context, items []*Item) error { - return cd.set(c, items, pb.MemcacheSetRequest_CAS) -} - -var ( - // Gob is a Codec that uses the gob package. - Gob = Codec{gobMarshal, gobUnmarshal} - // JSON is a Codec that uses the json package. - JSON = Codec{json.Marshal, json.Unmarshal} -) - -func gobMarshal(v interface{}) ([]byte, error) { - var buf bytes.Buffer - if err := gob.NewEncoder(&buf).Encode(v); err != nil { - return nil, err - } - return buf.Bytes(), nil -} - -func gobUnmarshal(data []byte, v interface{}) error { - return gob.NewDecoder(bytes.NewBuffer(data)).Decode(v) -} - -// Statistics represents a set of statistics about the memcache cache. -// This may include items that have expired but have not yet been removed from the cache. -type Statistics struct { - Hits uint64 // Counter of cache hits - Misses uint64 // Counter of cache misses - ByteHits uint64 // Counter of bytes transferred for gets - - Items uint64 // Items currently in the cache - Bytes uint64 // Size of all items currently in the cache - - Oldest int64 // Age of access of the oldest item, in seconds -} - -// Stats retrieves the current memcache statistics. -func Stats(c context.Context) (*Statistics, error) { - req := &pb.MemcacheStatsRequest{} - res := &pb.MemcacheStatsResponse{} - if err := internal.Call(c, "memcache", "Stats", req, res); err != nil { - return nil, err - } - if res.Stats == nil { - return nil, ErrNoStats - } - return &Statistics{ - Hits: *res.Stats.Hits, - Misses: *res.Stats.Misses, - ByteHits: *res.Stats.ByteHits, - Items: *res.Stats.Items, - Bytes: *res.Stats.Bytes, - Oldest: int64(*res.Stats.OldestItemAge), - }, nil -} - -// Flush flushes all items from memcache. -func Flush(c context.Context) error { - req := &pb.MemcacheFlushRequest{} - res := &pb.MemcacheFlushResponse{} - return internal.Call(c, "memcache", "FlushAll", req, res) -} - -func namespaceMod(m proto.Message, namespace string) { - switch m := m.(type) { - case *pb.MemcacheDeleteRequest: - if m.NameSpace == nil { - m.NameSpace = &namespace - } - case *pb.MemcacheGetRequest: - if m.NameSpace == nil { - m.NameSpace = &namespace - } - case *pb.MemcacheIncrementRequest: - if m.NameSpace == nil { - m.NameSpace = &namespace - } - case *pb.MemcacheSetRequest: - if m.NameSpace == nil { - m.NameSpace = &namespace - } - // MemcacheFlushRequest, MemcacheStatsRequest do not apply namespace. - } -} - -func init() { - internal.RegisterErrorCodeMap("memcache", pb.MemcacheServiceError_ErrorCode_name) - internal.NamespaceMods["memcache"] = namespaceMod -} |