dep ensure

8 files changed, 3082 insertions, 0 deletions

diff --git a/pkg/cache/cache.go b/pkg/cache/cache.go
new file mode 100644
index 0000000..db88d2f
--- /dev/null
+++ b/pkg/cache/cache.go
@@ -0,0 +1,1161 @@
+package cache
+
+import (
+	"encoding/gob"
+	"fmt"
+	"io"
+	"os"
+	"runtime"
+	"sync"
+	"time"
+)
+
+type Item struct {
+	Object     interface{}
+	Expiration int64
+}
+
+// Returns true if the item has expired.
+func (item Item) Expired() bool {
+	if item.Expiration == 0 {
+		return false
+	}
+	return time.Now().UnixNano() > item.Expiration
+}
+
+const (
+	// For use with functions that take an expiration time.
+	NoExpiration time.Duration = -1
+	// For use with functions that take an expiration time. Equivalent to
+	// passing in the same expiration duration as was given to New() or
+	// NewFrom() when the cache was created (e.g. 5 minutes.)
+	DefaultExpiration time.Duration = 0
+)
+
+type Cache struct {
+	*cache
+	// If this is confusing, see the comment at the bottom of New()
+}
+
+type cache struct {
+	defaultExpiration time.Duration
+	items             map[string]Item
+	mu                sync.RWMutex
+	onEvicted         func(string, interface{})
+	janitor           *janitor
+}
+
+// Add an item to the cache, replacing any existing item. If the duration is 0
+// (DefaultExpiration), the cache's default expiration time is used. If it is -1
+// (NoExpiration), the item never expires.
+func (c *cache) Set(k string, x interface{}, d time.Duration) {
+	// "Inlining" of set
+	var e int64
+	if d == DefaultExpiration {
+		d = c.defaultExpiration
+	}
+	if d > 0 {
+		e = time.Now().Add(d).UnixNano()
+	}
+	c.mu.Lock()
+	c.items[k] = Item{
+		Object:     x,
+		Expiration: e,
+	}
+	// TODO: Calls to mu.Unlock are currently not deferred because defer
+	// adds ~200 ns (as of go1.)
+	c.mu.Unlock()
+}
+
+func (c *cache) set(k string, x interface{}, d time.Duration) {
+	var e int64
+	if d == DefaultExpiration {
+		d = c.defaultExpiration
+	}
+	if d > 0 {
+		e = time.Now().Add(d).UnixNano()
+	}
+	c.items[k] = Item{
+		Object:     x,
+		Expiration: e,
+	}
+}
+
+// Add an item to the cache, replacing any existing item, using the default
+// expiration.
+func (c *cache) SetDefault(k string, x interface{}) {
+	c.Set(k, x, DefaultExpiration)
+}
+
+// Add an item to the cache only if an item doesn't already exist for the given
+// key, or if the existing item has expired. Returns an error otherwise.
+func (c *cache) Add(k string, x interface{}, d time.Duration) error {
+	c.mu.Lock()
+	_, found := c.get(k)
+	if found {
+		c.mu.Unlock()
+		return fmt.Errorf("Item %s already exists", k)
+	}
+	c.set(k, x, d)
+	c.mu.Unlock()
+	return nil
+}
+
+// Set a new value for the cache key only if it already exists, and the existing
+// item hasn't expired. Returns an error otherwise.
+func (c *cache) Replace(k string, x interface{}, d time.Duration) error {
+	c.mu.Lock()
+	_, found := c.get(k)
+	if !found {
+		c.mu.Unlock()
+		return fmt.Errorf("Item %s doesn't exist", k)
+	}
+	c.set(k, x, d)
+	c.mu.Unlock()
+	return nil
+}
+
+// Get an item from the cache. Returns the item or nil, and a bool indicating
+// whether the key was found.
+func (c *cache) Get(k string) (interface{}, bool) {
+	c.mu.RLock()
+	// "Inlining" of get and Expired
+	item, found := c.items[k]
+	if !found {
+		c.mu.RUnlock()
+		return nil, false
+	}
+	if item.Expiration > 0 {
+		if time.Now().UnixNano() > item.Expiration {
+			c.mu.RUnlock()
+			return nil, false
+		}
+	}
+	c.mu.RUnlock()
+	return item.Object, true
+}
+
+// GetWithExpiration returns an item and its expiration time from the cache.
+// It returns the item or nil, the expiration time if one is set (if the item
+// never expires a zero value for time.Time is returned), and a bool indicating
+// whether the key was found.
+func (c *cache) GetWithExpiration(k string) (interface{}, time.Time, bool) {
+	c.mu.RLock()
+	// "Inlining" of get and Expired
+	item, found := c.items[k]
+	if !found {
+		c.mu.RUnlock()
+		return nil, time.Time{}, false
+	}
+
+	if item.Expiration > 0 {
+		if time.Now().UnixNano() > item.Expiration {
+			c.mu.RUnlock()
+			return nil, time.Time{}, false
+		}
+
+		// Return the item and the expiration time
+		c.mu.RUnlock()
+		return item.Object, time.Unix(0, item.Expiration), true
+	}
+
+	// If expiration <= 0 (i.e. no expiration time set) then return the item
+	// and a zeroed time.Time
+	c.mu.RUnlock()
+	return item.Object, time.Time{}, true
+}
+
+func (c *cache) get(k string) (interface{}, bool) {
+	item, found := c.items[k]
+	if !found {
+		return nil, false
+	}
+	// "Inlining" of Expired
+	if item.Expiration > 0 {
+		if time.Now().UnixNano() > item.Expiration {
+			return nil, false
+		}
+	}
+	return item.Object, true
+}
+
+// Increment an item of type int, int8, int16, int32, int64, uintptr, uint,
+// uint8, uint32, or uint64, float32 or float64 by n. Returns an error if the
+// item's value is not an integer, if it was not found, or if it is not
+// possible to increment it by n. To retrieve the incremented value, use one
+// of the specialized methods, e.g. IncrementInt64.
+func (c *cache) Increment(k string, n int64) error {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return fmt.Errorf("Item %s not found", k)
+	}
+	switch v.Object.(type) {
+	case int:
+		v.Object = v.Object.(int) + int(n)
+	case int8:
+		v.Object = v.Object.(int8) + int8(n)
+	case int16:
+		v.Object = v.Object.(int16) + int16(n)
+	case int32:
+		v.Object = v.Object.(int32) + int32(n)
+	case int64:
+		v.Object = v.Object.(int64) + n
+	case uint:
+		v.Object = v.Object.(uint) + uint(n)
+	case uintptr:
+		v.Object = v.Object.(uintptr) + uintptr(n)
+	case uint8:
+		v.Object = v.Object.(uint8) + uint8(n)
+	case uint16:
+		v.Object = v.Object.(uint16) + uint16(n)
+	case uint32:
+		v.Object = v.Object.(uint32) + uint32(n)
+	case uint64:
+		v.Object = v.Object.(uint64) + uint64(n)
+	case float32:
+		v.Object = v.Object.(float32) + float32(n)
+	case float64:
+		v.Object = v.Object.(float64) + float64(n)
+	default:
+		c.mu.Unlock()
+		return fmt.Errorf("The value for %s is not an integer", k)
+	}
+	c.items[k] = v
+	c.mu.Unlock()
+	return nil
+}
+
+// Increment an item of type float32 or float64 by n. Returns an error if the
+// item's value is not floating point, if it was not found, or if it is not
+// possible to increment it by n. Pass a negative number to decrement the
+// value. To retrieve the incremented value, use one of the specialized methods,
+// e.g. IncrementFloat64.
+func (c *cache) IncrementFloat(k string, n float64) error {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return fmt.Errorf("Item %s not found", k)
+	}
+	switch v.Object.(type) {
+	case float32:
+		v.Object = v.Object.(float32) + float32(n)
+	case float64:
+		v.Object = v.Object.(float64) + n
+	default:
+		c.mu.Unlock()
+		return fmt.Errorf("The value for %s does not have type float32 or float64", k)
+	}
+	c.items[k] = v
+	c.mu.Unlock()
+	return nil
+}
+
+// Increment an item of type int by n. Returns an error if the item's value is
+// not an int, or if it was not found. If there is no error, the incremented
+// value is returned.
+func (c *cache) IncrementInt(k string, n int) (int, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(int)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an int", k)
+	}
+	nv := rv + n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Increment an item of type int8 by n. Returns an error if the item's value is
+// not an int8, or if it was not found. If there is no error, the incremented
+// value is returned.
+func (c *cache) IncrementInt8(k string, n int8) (int8, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(int8)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an int8", k)
+	}
+	nv := rv + n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Increment an item of type int16 by n. Returns an error if the item's value is
+// not an int16, or if it was not found. If there is no error, the incremented
+// value is returned.
+func (c *cache) IncrementInt16(k string, n int16) (int16, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(int16)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an int16", k)
+	}
+	nv := rv + n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Increment an item of type int32 by n. Returns an error if the item's value is
+// not an int32, or if it was not found. If there is no error, the incremented
+// value is returned.
+func (c *cache) IncrementInt32(k string, n int32) (int32, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(int32)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an int32", k)
+	}
+	nv := rv + n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Increment an item of type int64 by n. Returns an error if the item's value is
+// not an int64, or if it was not found. If there is no error, the incremented
+// value is returned.
+func (c *cache) IncrementInt64(k string, n int64) (int64, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(int64)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an int64", k)
+	}
+	nv := rv + n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Increment an item of type uint by n. Returns an error if the item's value is
+// not an uint, or if it was not found. If there is no error, the incremented
+// value is returned.
+func (c *cache) IncrementUint(k string, n uint) (uint, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(uint)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an uint", k)
+	}
+	nv := rv + n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Increment an item of type uintptr by n. Returns an error if the item's value
+// is not an uintptr, or if it was not found. If there is no error, the
+// incremented value is returned.
+func (c *cache) IncrementUintptr(k string, n uintptr) (uintptr, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(uintptr)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an uintptr", k)
+	}
+	nv := rv + n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Increment an item of type uint8 by n. Returns an error if the item's value
+// is not an uint8, or if it was not found. If there is no error, the
+// incremented value is returned.
+func (c *cache) IncrementUint8(k string, n uint8) (uint8, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(uint8)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an uint8", k)
+	}
+	nv := rv + n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Increment an item of type uint16 by n. Returns an error if the item's value
+// is not an uint16, or if it was not found. If there is no error, the
+// incremented value is returned.
+func (c *cache) IncrementUint16(k string, n uint16) (uint16, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(uint16)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an uint16", k)
+	}
+	nv := rv + n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Increment an item of type uint32 by n. Returns an error if the item's value
+// is not an uint32, or if it was not found. If there is no error, the
+// incremented value is returned.
+func (c *cache) IncrementUint32(k string, n uint32) (uint32, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(uint32)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an uint32", k)
+	}
+	nv := rv + n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Increment an item of type uint64 by n. Returns an error if the item's value
+// is not an uint64, or if it was not found. If there is no error, the
+// incremented value is returned.
+func (c *cache) IncrementUint64(k string, n uint64) (uint64, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(uint64)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an uint64", k)
+	}
+	nv := rv + n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Increment an item of type float32 by n. Returns an error if the item's value
+// is not an float32, or if it was not found. If there is no error, the
+// incremented value is returned.
+func (c *cache) IncrementFloat32(k string, n float32) (float32, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(float32)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an float32", k)
+	}
+	nv := rv + n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Increment an item of type float64 by n. Returns an error if the item's value
+// is not an float64, or if it was not found. If there is no error, the
+// incremented value is returned.
+func (c *cache) IncrementFloat64(k string, n float64) (float64, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(float64)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an float64", k)
+	}
+	nv := rv + n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Decrement an item of type int, int8, int16, int32, int64, uintptr, uint,
+// uint8, uint32, or uint64, float32 or float64 by n. Returns an error if the
+// item's value is not an integer, if it was not found, or if it is not
+// possible to decrement it by n. To retrieve the decremented value, use one
+// of the specialized methods, e.g. DecrementInt64.
+func (c *cache) Decrement(k string, n int64) error {
+	// TODO: Implement Increment and Decrement more cleanly.
+	// (Cannot do Increment(k, n*-1) for uints.)
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return fmt.Errorf("Item not found")
+	}
+	switch v.Object.(type) {
+	case int:
+		v.Object = v.Object.(int) - int(n)
+	case int8:
+		v.Object = v.Object.(int8) - int8(n)
+	case int16:
+		v.Object = v.Object.(int16) - int16(n)
+	case int32:
+		v.Object = v.Object.(int32) - int32(n)
+	case int64:
+		v.Object = v.Object.(int64) - n
+	case uint:
+		v.Object = v.Object.(uint) - uint(n)
+	case uintptr:
+		v.Object = v.Object.(uintptr) - uintptr(n)
+	case uint8:
+		v.Object = v.Object.(uint8) - uint8(n)
+	case uint16:
+		v.Object = v.Object.(uint16) - uint16(n)
+	case uint32:
+		v.Object = v.Object.(uint32) - uint32(n)
+	case uint64:
+		v.Object = v.Object.(uint64) - uint64(n)
+	case float32:
+		v.Object = v.Object.(float32) - float32(n)
+	case float64:
+		v.Object = v.Object.(float64) - float64(n)
+	default:
+		c.mu.Unlock()
+		return fmt.Errorf("The value for %s is not an integer", k)
+	}
+	c.items[k] = v
+	c.mu.Unlock()
+	return nil
+}
+
+// Decrement an item of type float32 or float64 by n. Returns an error if the
+// item's value is not floating point, if it was not found, or if it is not
+// possible to decrement it by n. Pass a negative number to decrement the
+// value. To retrieve the decremented value, use one of the specialized methods,
+// e.g. DecrementFloat64.
+func (c *cache) DecrementFloat(k string, n float64) error {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return fmt.Errorf("Item %s not found", k)
+	}
+	switch v.Object.(type) {
+	case float32:
+		v.Object = v.Object.(float32) - float32(n)
+	case float64:
+		v.Object = v.Object.(float64) - n
+	default:
+		c.mu.Unlock()
+		return fmt.Errorf("The value for %s does not have type float32 or float64", k)
+	}
+	c.items[k] = v
+	c.mu.Unlock()
+	return nil
+}
+
+// Decrement an item of type int by n. Returns an error if the item's value is
+// not an int, or if it was not found. If there is no error, the decremented
+// value is returned.
+func (c *cache) DecrementInt(k string, n int) (int, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(int)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an int", k)
+	}
+	nv := rv - n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Decrement an item of type int8 by n. Returns an error if the item's value is
+// not an int8, or if it was not found. If there is no error, the decremented
+// value is returned.
+func (c *cache) DecrementInt8(k string, n int8) (int8, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(int8)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an int8", k)
+	}
+	nv := rv - n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Decrement an item of type int16 by n. Returns an error if the item's value is
+// not an int16, or if it was not found. If there is no error, the decremented
+// value is returned.
+func (c *cache) DecrementInt16(k string, n int16) (int16, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(int16)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an int16", k)
+	}
+	nv := rv - n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Decrement an item of type int32 by n. Returns an error if the item's value is
+// not an int32, or if it was not found. If there is no error, the decremented
+// value is returned.
+func (c *cache) DecrementInt32(k string, n int32) (int32, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(int32)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an int32", k)
+	}
+	nv := rv - n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Decrement an item of type int64 by n. Returns an error if the item's value is
+// not an int64, or if it was not found. If there is no error, the decremented
+// value is returned.
+func (c *cache) DecrementInt64(k string, n int64) (int64, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(int64)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an int64", k)
+	}
+	nv := rv - n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Decrement an item of type uint by n. Returns an error if the item's value is
+// not an uint, or if it was not found. If there is no error, the decremented
+// value is returned.
+func (c *cache) DecrementUint(k string, n uint) (uint, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(uint)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an uint", k)
+	}
+	nv := rv - n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Decrement an item of type uintptr by n. Returns an error if the item's value
+// is not an uintptr, or if it was not found. If there is no error, the
+// decremented value is returned.
+func (c *cache) DecrementUintptr(k string, n uintptr) (uintptr, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(uintptr)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an uintptr", k)
+	}
+	nv := rv - n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Decrement an item of type uint8 by n. Returns an error if the item's value is
+// not an uint8, or if it was not found. If there is no error, the decremented
+// value is returned.
+func (c *cache) DecrementUint8(k string, n uint8) (uint8, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(uint8)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an uint8", k)
+	}
+	nv := rv - n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Decrement an item of type uint16 by n. Returns an error if the item's value
+// is not an uint16, or if it was not found. If there is no error, the
+// decremented value is returned.
+func (c *cache) DecrementUint16(k string, n uint16) (uint16, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(uint16)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an uint16", k)
+	}
+	nv := rv - n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Decrement an item of type uint32 by n. Returns an error if the item's value
+// is not an uint32, or if it was not found. If there is no error, the
+// decremented value is returned.
+func (c *cache) DecrementUint32(k string, n uint32) (uint32, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(uint32)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an uint32", k)
+	}
+	nv := rv - n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Decrement an item of type uint64 by n. Returns an error if the item's value
+// is not an uint64, or if it was not found. If there is no error, the
+// decremented value is returned.
+func (c *cache) DecrementUint64(k string, n uint64) (uint64, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(uint64)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an uint64", k)
+	}
+	nv := rv - n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Decrement an item of type float32 by n. Returns an error if the item's value
+// is not an float32, or if it was not found. If there is no error, the
+// decremented value is returned.
+func (c *cache) DecrementFloat32(k string, n float32) (float32, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(float32)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an float32", k)
+	}
+	nv := rv - n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Decrement an item of type float64 by n. Returns an error if the item's value
+// is not an float64, or if it was not found. If there is no error, the
+// decremented value is returned.
+func (c *cache) DecrementFloat64(k string, n float64) (float64, error) {
+	c.mu.Lock()
+	v, found := c.items[k]
+	if !found || v.Expired() {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("Item %s not found", k)
+	}
+	rv, ok := v.Object.(float64)
+	if !ok {
+		c.mu.Unlock()
+		return 0, fmt.Errorf("The value for %s is not an float64", k)
+	}
+	nv := rv - n
+	v.Object = nv
+	c.items[k] = v
+	c.mu.Unlock()
+	return nv, nil
+}
+
+// Delete an item from the cache. Does nothing if the key is not in the cache.
+func (c *cache) Delete(k string) {
+	c.mu.Lock()
+	v, evicted := c.delete(k)
+	c.mu.Unlock()
+	if evicted {
+		c.onEvicted(k, v)
+	}
+}
+
+func (c *cache) delete(k string) (interface{}, bool) {
+	if c.onEvicted != nil {
+		if v, found := c.items[k]; found {
+			delete(c.items, k)
+			return v.Object, true
+		}
+	}
+	delete(c.items, k)
+	return nil, false
+}
+
+type keyAndValue struct {
+	key   string
+	value interface{}
+}
+
+// Delete all expired items from the cache.
+func (c *cache) DeleteExpired() {
+	var evictedItems []keyAndValue
+	now := time.Now().UnixNano()
+	c.mu.Lock()
+	for k, v := range c.items {
+		// "Inlining" of expired
+		if v.Expiration > 0 && now > v.Expiration {
+			ov, evicted := c.delete(k)
+			if evicted {
+				evictedItems = append(evictedItems, keyAndValue{k, ov})
+			}
+		}
+	}
+	c.mu.Unlock()
+	for _, v := range evictedItems {
+		c.onEvicted(v.key, v.value)
+	}
+}
+
+// Sets an (optional) function that is called with the key and value when an
+// item is evicted from the cache. (Including when it is deleted manually, but
+// not when it is overwritten.) Set to nil to disable.
+func (c *cache) OnEvicted(f func(string, interface{})) {
+	c.mu.Lock()
+	c.onEvicted = f
+	c.mu.Unlock()
+}
+
+// Write the cache's items (using Gob) to an io.Writer.
+//
+// NOTE: This method is deprecated in favor of c.Items() and NewFrom() (see the
+// documentation for NewFrom().)
+func (c *cache) Save(w io.Writer) (err error) {
+	enc := gob.NewEncoder(w)
+	defer func() {
+		if x := recover(); x != nil {
+			err = fmt.Errorf("Error registering item types with Gob library")
+		}
+	}()
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	for _, v := range c.items {
+		gob.Register(v.Object)
+	}
+	err = enc.Encode(&c.items)
+	return
+}
+
+// Save the cache's items to the given filename, creating the file if it
+// doesn't exist, and overwriting it if it does.
+//
+// NOTE: This method is deprecated in favor of c.Items() and NewFrom() (see the
+// documentation for NewFrom().)
+func (c *cache) SaveFile(fname string) error {
+	fp, err := os.Create(fname)
+	if err != nil {
+		return err
+	}
+	err = c.Save(fp)
+	if err != nil {
+		fp.Close()
+		return err
+	}
+	return fp.Close()
+}
+
+// Add (Gob-serialized) cache items from an io.Reader, excluding any items with
+// keys that already exist (and haven't expired) in the current cache.
+//
+// NOTE: This method is deprecated in favor of c.Items() and NewFrom() (see the
+// documentation for NewFrom().)
+func (c *cache) Load(r io.Reader) error {
+	dec := gob.NewDecoder(r)
+	items := map[string]Item{}
+	err := dec.Decode(&items)
+	if err == nil {
+		c.mu.Lock()
+		defer c.mu.Unlock()
+		for k, v := range items {
+			ov, found := c.items[k]
+			if !found || ov.Expired() {
+				c.items[k] = v
+			}
+		}
+	}
+	return err
+}
+
+// Load and add cache items from the given filename, excluding any items with
+// keys that already exist in the current cache.
+//
+// NOTE: This method is deprecated in favor of c.Items() and NewFrom() (see the
+// documentation for NewFrom().)
+func (c *cache) LoadFile(fname string) error {
+	fp, err := os.Open(fname)
+	if err != nil {
+		return err
+	}
+	err = c.Load(fp)
+	if err != nil {
+		fp.Close()
+		return err
+	}
+	return fp.Close()
+}
+
+// Copies all unexpired items in the cache into a new map and returns it.
+func (c *cache) Items() map[string]Item {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	m := make(map[string]Item, len(c.items))
+	now := time.Now().UnixNano()
+	for k, v := range c.items {
+		// "Inlining" of Expired
+		if v.Expiration > 0 {
+			if now > v.Expiration {
+				continue
+			}
+		}
+		m[k] = v
+	}
+	return m
+}
+
+// Returns the number of items in the cache. This may include items that have
+// expired, but have not yet been cleaned up.
+func (c *cache) ItemCount() int {
+	c.mu.RLock()
+	n := len(c.items)
+	c.mu.RUnlock()
+	return n
+}
+
+// Delete all items from the cache.
+func (c *cache) Flush() {
+	c.mu.Lock()
+	c.items = map[string]Item{}
+	c.mu.Unlock()
+}
+
+type janitor struct {
+	Interval time.Duration
+	stop     chan bool
+}
+
+func (j *janitor) Run(c *cache) {
+	ticker := time.NewTicker(j.Interval)
+	for {
+		select {
+		case <-ticker.C:
+			c.DeleteExpired()
+		case <-j.stop:
+			ticker.Stop()
+			return
+		}
+	}
+}
+
+func stopJanitor(c *Cache) {
+	c.janitor.stop <- true
+}
+
+func runJanitor(c *cache, ci time.Duration) {
+	j := &janitor{
+		Interval: ci,
+		stop:     make(chan bool),
+	}
+	c.janitor = j
+	go j.Run(c)
+}
+
+func newCache(de time.Duration, m map[string]Item) *cache {
+	if de == 0 {
+		de = -1
+	}
+	c := &cache{
+		defaultExpiration: de,
+		items:             m,
+	}
+	return c
+}
+
+func newCacheWithJanitor(de time.Duration, ci time.Duration, m map[string]Item) *Cache {
+	c := newCache(de, m)
+	// This trick ensures that the janitor goroutine (which--granted it
+	// was enabled--is running DeleteExpired on c forever) does not keep
+	// the returned C object from being garbage collected. When it is
+	// garbage collected, the finalizer stops the janitor goroutine, after
+	// which c can be collected.
+	C := &Cache{c}
+	if ci > 0 {
+		runJanitor(c, ci)
+		runtime.SetFinalizer(C, stopJanitor)
+	}
+	return C
+}
+
+// Return a new cache with a given default expiration duration and cleanup
+// interval. If the expiration duration is less than one (or NoExpiration),
+// the items in the cache never expire (by default), and must be deleted
+// manually. If the cleanup interval is less than one, expired items are not
+// deleted from the cache before calling c.DeleteExpired().
+func New(defaultExpiration, cleanupInterval time.Duration) *Cache {
+	items := make(map[string]Item)
+	return newCacheWithJanitor(defaultExpiration, cleanupInterval, items)
+}
+
+// Return a new cache with a given default expiration duration and cleanup