1 files changed, 125 insertions, 0 deletions
diff --git a/Godeps/_workspace/src/github.com/syndtr/goleveldb/leveldb/cache/cache.go b/Godeps/_workspace/src/github.com/syndtr/goleveldb/leveldb/cache/cache.go
new file mode 100644
index 000000000..9b6a74977
--- /dev/null
+++ b/Godeps/_workspace/src/github.com/syndtr/goleveldb/leveldb/cache/cache.go
@@ -0,0 +1,125 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Package cache provides interface and implementation of a cache algorithms.
+package cache
+
+import (
+	"sync/atomic"
+)
+
+// SetFunc used by Namespace.Get method to create a cache object. SetFunc
+// may return ok false, in that case the cache object will not be created.
+type SetFunc func() (ok bool, value interface{}, charge int, fin SetFin)
+
+// SetFin will be called when corresponding cache object are released.
+type SetFin func()
+
+// DelFin will be called when corresponding cache object are released.
+// DelFin will be called after SetFin. The exist is true if the corresponding
+// cache object is actually exist in the cache tree.
+type DelFin func(exist bool)
+
+// PurgeFin will be called when corresponding cache object are released.
+// PurgeFin will be called after SetFin. If PurgeFin present DelFin will
+// not be executed but passed to the PurgeFin, it is up to the caller
+// to call it or not.
+type PurgeFin func(ns, key uint64, delfin DelFin)
+
+// Cache is a cache tree.
+type Cache interface {
+	// SetCapacity sets cache capacity.
+	SetCapacity(capacity int)
+
+	// GetNamespace gets or creates a cache namespace for the given id.
+	GetNamespace(id uint64) Namespace
+
+	// Purge purges all cache namespaces, read Namespace.Purge method documentation.
+	Purge(fin PurgeFin)
+
+	// Zap zaps all cache namespaces, read Namespace.Zap method documentation.
+	Zap(closed bool)
+}
+
+// Namespace is a cache namespace.
+type Namespace interface {
+	// Get gets cache object for the given key. The given SetFunc (if not nil) will
+	// be called if the given key does not exist.
+	// If the given key does not exist, SetFunc is nil or SetFunc return ok false, Get
+	// will return ok false.
+	Get(key uint64, setf SetFunc) (obj Object, ok bool)
+
+	// Get deletes cache object for the given key. If exist the cache object will
+	// be deleted later when all of its handles have been released (i.e. no one use
+	// it anymore) and the given DelFin (if not nil) will finally be  executed. If
+	// such cache object does not exist the given DelFin will be executed anyway.
+	//
+	// Delete returns true if such cache object exist.
+	Delete(key uint64, fin DelFin) bool
+
+	// Purge deletes all cache objects, read Delete method documentation.
+	Purge(fin PurgeFin)
+
+	// Zap detaches the namespace from the cache tree and delete all its cache
+	// objects. The cache objects deletion and finalizers execution are happen
+	// immediately, even if its existing handles haven't yet been released.
+	// A zapped namespace can't never be filled again.
+	// If closed is false then the Get function will always call the given SetFunc
+	// if it is not nil, but resultant of the SetFunc will not be cached.
+	Zap(closed bool)
+}
+
+// Object is a cache object.
+type Object interface {
+	// Release releases the cache object. Other methods should not be called
+	// after the cache object has been released.
+	Release()
+
+	// Value returns value of the cache object.
+	Value() interface{}
+}
+
+// Namespace state.
+type nsState int
+
+const (
+	nsEffective nsState = iota
+	nsZapped
+	nsClosed
+)
+
+// Node state.
+type nodeState int
+
+const (
+	nodeEffective nodeState = iota
+	nodeEvicted
+	nodeRemoved
+)
+
+// Fake object.
+type fakeObject struct {
+	value interface{}
+	fin   func()
+	once  uint32
+}
+
+func (o *fakeObject) Value() interface{} {
+	if atomic.LoadUint32(&o.once) == 0 {
+		return o.value
+	}
+	return nil
+}
+
+func (o *fakeObject) Release() {
+	if !atomic.CompareAndSwapUint32(&o.once, 0, 1) {
+		return
+	}
+	if o.fin != nil {
+		o.fin()
+		o.fin = nil
+	}
+}