godeps: update leveldb and snappy, dump serpent-go

1 files changed, 632 insertions, 81 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
index 9b6a74977..c9670de5d 100644
--- a/Godeps/_workspace/src/github.com/syndtr/goleveldb/leveldb/cache/cache.go
+++ b/Godeps/_workspace/src/github.com/syndtr/goleveldb/leveldb/cache/cache.go
@@ -8,118 +8,669 @@
 package cache
 
 import (
+	"sync"
 	"sync/atomic"
+	"unsafe"
+
+	"github.com/syndtr/goleveldb/leveldb/util"
 )
 
-// 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)
+// Cacher provides interface to implements a caching functionality.
+// An implementation must be goroutine-safe.
+type Cacher interface {
+	// Capacity returns cache capacity.
+	Capacity() int
 
-// SetFin will be called when corresponding cache object are released.
-type SetFin func()
+	// SetCapacity sets cache capacity.
+	SetCapacity(capacity int)
 
-// 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)
+	// Promote promotes the 'cache node'.
+	Promote(n *Node)
 
-// 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)
+	// Ban evicts the 'cache node' and prevent subsequent 'promote'.
+	Ban(n *Node)
 
-// Cache is a cache tree.
-type Cache interface {
-	// SetCapacity sets cache capacity.
-	SetCapacity(capacity int)
+	// Evict evicts the 'cache node'.
+	Evict(n *Node)
 
-	// GetNamespace gets or creates a cache namespace for the given id.
-	GetNamespace(id uint64) Namespace
+	// EvictNS evicts 'cache node' with the given namespace.
+	EvictNS(ns uint64)
 
-	// Purge purges all cache namespaces, read Namespace.Purge method documentation.
-	Purge(fin PurgeFin)
+	// EvictAll evicts all 'cache node'.
+	EvictAll()
+
+	// Close closes the 'cache tree'
+	Close() error
+}
+
+// Value is a 'cacheable object'. It may implements util.Releaser, if
+// so the the Release method will be called once object is released.
+type Value interface{}
+
+type CacheGetter struct {
+	Cache *Cache
+	NS    uint64
+}
 
-	// Zap zaps all cache namespaces, read Namespace.Zap method documentation.
-	Zap(closed bool)
+func (g *CacheGetter) Get(key uint64, setFunc func() (size int, value Value)) *Handle {
+	return g.Cache.Get(g.NS, key, setFunc)
 }
 
-// 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)
+// The hash tables implementation is based on:
+// "Dynamic-Sized Nonblocking Hash Tables", by Yujie Liu, Kunlong Zhang, and Michael Spear. ACM Symposium on Principles of Distributed Computing, Jul 2014.
 
-	// 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
+const (
+	mInitialSize           = 1 << 4
+	mOverflowThreshold     = 1 << 5
+	mOverflowGrowThreshold = 1 << 7
+)
 
-	// Purge deletes all cache objects, read Delete method documentation.
-	Purge(fin PurgeFin)
+type mBucket struct {
+	mu     sync.Mutex
+	node   []*Node
+	frozen bool
+}
 
-	// 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)
+func (b *mBucket) freeze() []*Node {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	if !b.frozen {
+		b.frozen = true
+	}
+	return b.node
 }
 
-// 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()
+func (b *mBucket) get(r *Cache, h *mNode, hash uint32, ns, key uint64, noset bool) (done, added bool, n *Node) {
+	b.mu.Lock()
+
+	if b.frozen {
+		b.mu.Unlock()
+		return
+	}
+
+	// Scan the node.
+	for _, n := range b.node {
+		if n.hash == hash && n.ns == ns && n.key == key {
+			atomic.AddInt32(&n.ref, 1)
+			b.mu.Unlock()
+			return true, false, n
+		}
+	}
+
+	// Get only.
+	if noset {
+		b.mu.Unlock()
+		return true, false, nil
+	}
+
+	// Create node.
+	n = &Node{
+		r:    r,
+		hash: hash,
+		ns:   ns,
+		key:  key,
+		ref:  1,
+	}
+	// Add node to bucket.
+	b.node = append(b.node, n)
+	bLen := len(b.node)
+	b.mu.Unlock()
+
+	// Update counter.
+	grow := atomic.AddInt32(&r.nodes, 1) >= h.growThreshold
+	if bLen > mOverflowThreshold {
+		grow = grow || atomic.AddInt32(&h.overflow, 1) >= mOverflowGrowThreshold
+	}
 
-	// Value returns value of the cache object.
-	Value() interface{}
+	// Grow.
+	if grow && atomic.CompareAndSwapInt32(&h.resizeInProgess, 0, 1) {
+		nhLen := len(h.buckets) << 1
+		nh := &mNode{
+			buckets:         make([]unsafe.Pointer, nhLen),
+			mask:            uint32(nhLen) - 1,
+			pred:            unsafe.Pointer(h),
+			growThreshold:   int32(nhLen * mOverflowThreshold),
+			shrinkThreshold: int32(nhLen >> 1),
+		}
+		ok := atomic.CompareAndSwapPointer(&r.mHead, unsafe.Pointer(h), unsafe.Pointer(nh))
+		if !ok {
+			panic("BUG: failed swapping head")
+		}
+		go nh.initBuckets()
+	}
+
+	return true, true, n
 }
 
-// Namespace state.
-type nsState int
+func (b *mBucket) delete(r *Cache, h *mNode, hash uint32, ns, key uint64) (done, deleted bool) {
+	b.mu.Lock()
 
-const (
-	nsEffective nsState = iota
-	nsZapped
-	nsClosed
-)
+	if b.frozen {
+		b.mu.Unlock()
+		return
+	}
 
-// Node state.
-type nodeState int
+	// Scan the node.
+	var (
+		n    *Node
+		bLen int
+	)
+	for i := range b.node {
+		n = b.node[i]
+		if n.ns == ns && n.key == key {
+			if atomic.LoadInt32(&n.ref) == 0 {
+				deleted = true
 
-const (
-	nodeEffective nodeState = iota
-	nodeEvicted
-	nodeRemoved
-)
+				// Call releaser.
+				if n.value != nil {
+					if r, ok := n.value.(util.Releaser); ok {
+						r.Release()
+					}
+					n.value = nil
+				}
+
+				// Remove node from bucket.
+				b.node = append(b.node[:i], b.node[i+1:]...)
+				bLen = len(b.node)
+			}
+			break
+		}
+	}
+	b.mu.Unlock()
 
-// Fake object.
-type fakeObject struct {
-	value interface{}
-	fin   func()
-	once  uint32
+	if deleted {
+		// Call OnDel.
+		for _, f := range n.onDel {
+			f()
+		}
+
+		// Update counter.
+		atomic.AddInt32(&r.size, int32(n.size)*-1)
+		shrink := atomic.AddInt32(&r.nodes, -1) < h.shrinkThreshold
+		if bLen >= mOverflowThreshold {
+			atomic.AddInt32(&h.overflow, -1)
+		}
+
+		// Shrink.
+		if shrink && len(h.buckets) > mInitialSize && atomic.CompareAndSwapInt32(&h.resizeInProgess, 0, 1) {
+			nhLen := len(h.buckets) >> 1
+			nh := &mNode{
+				buckets:         make([]unsafe.Pointer, nhLen),
+				mask:            uint32(nhLen) - 1,
+				pred:            unsafe.Pointer(h),
+				growThreshold:   int32(nhLen * mOverflowThreshold),
+				shrinkThreshold: int32(nhLen >> 1),
+			}
+			ok := atomic.CompareAndSwapPointer(&r.mHead, unsafe.Pointer(h), unsafe.Pointer(nh))
+			if !ok {
+				panic("BUG: failed swapping head")
+			}
+			go nh.initBuckets()
+		}
+	}
+
+	return true, deleted
 }
 
-func (o *fakeObject) Value() interface{} {
-	if atomic.LoadUint32(&o.once) == 0 {
-		return o.value
+type mNode struct {
+	buckets         []unsafe.Pointer // []*mBucket
+	mask            uint32
+	pred            unsafe.Pointer // *mNode
+	resizeInProgess int32
+
+	overflow        int32
+	growThreshold   int32
+	shrinkThreshold int32
+}
+
+func (n *mNode) initBucket(i uint32) *mBucket {
+	if b := (*mBucket)(atomic.LoadPointer(&n.buckets[i])); b != nil {
+		return b
+	}
+
+	p := (*mNode)(atomic.LoadPointer(&n.pred))
+	if p != nil {
+		var node []*Node
+		if n.mask > p.mask {
+			// Grow.
+			pb := (*mBucket)(atomic.LoadPointer(&p.buckets[i&p.mask]))
+			if pb == nil {
+				pb = p.initBucket(i & p.mask)
+			}
+			m := pb.freeze()
+			// Split nodes.
+			for _, x := range m {
+				if x.hash&n.mask == i {
+					node = append(node, x)
+				}
+			}
+		} else {
+			// Shrink.
+			pb0 := (*mBucket)(atomic.LoadPointer(&p.buckets[i]))
+			if pb0 == nil {
+				pb0 = p.initBucket(i)
+			}
+			pb1 := (*mBucket)(atomic.LoadPointer(&p.buckets[i+uint32(len(n.buckets))]))
+			if pb1 == nil {
+				pb1 = p.initBucket(i + uint32(len(n.buckets)))
+			}
+			m0 := pb0.freeze()
+			m1 := pb1.freeze()
+			// Merge nodes.
+			node = make([]*Node, 0, len(m0)+len(m1))
+			node = append(node, m0...)
+			node = append(node, m1...)
+		}
+		b := &mBucket{node: node}
+		if atomic.CompareAndSwapPointer(&n.buckets[i], nil, unsafe.Pointer(b)) {
+			if len(node) > mOverflowThreshold {
+				atomic.AddInt32(&n.overflow, int32(len(node)-mOverflowThreshold))
+			}
+			return b
+		}
+	}
+
+	return (*mBucket)(atomic.LoadPointer(&n.buckets[i]))
+}
+
+func (n *mNode) initBuckets() {
+	for i := range n.buckets {
+		n.initBucket(uint32(i))
+	}
+	atomic.StorePointer(&n.pred, nil)
+}
+
+// Cache is a 'cache map'.
+type Cache struct {
+	mu     sync.RWMutex
+	mHead  unsafe.Pointer // *mNode
+	nodes  int32
+	size   int32
+	cacher Cacher
+	closed bool
+}
+
+// NewCache creates a new 'cache map'. The cacher is optional and
+// may be nil.
+func NewCache(cacher Cacher) *Cache {
+	h := &mNode{
+		buckets:         make([]unsafe.Pointer, mInitialSize),
+		mask:            mInitialSize - 1,
+		growThreshold:   int32(mInitialSize * mOverflowThreshold),
+		shrinkThreshold: 0,
+	}
+	for i := range h.buckets {
+		h.buckets[i] = unsafe.Pointer(&mBucket{})
+	}
+	r := &Cache{
+		mHead:  unsafe.Pointer(h),
+		cacher: cacher,
+	}
+	return r
+}
+
+func (r *Cache) getBucket(hash uint32) (*mNode, *mBucket) {
+	h := (*mNode)(atomic.LoadPointer(&r.mHead))
+	i := hash & h.mask
+	b := (*mBucket)(atomic.LoadPointer(&h.buckets[i]))
+	if b == nil {
+		b = h.initBucket(i)
+	}
+	return h, b
+}
+
+func (r *Cache) delete(n *Node) bool {
+	for {
+		h, b := r.getBucket(n.hash)
+		done, deleted := b.delete(r, h, n.hash, n.ns, n.key)
+		if done {
+			return deleted
+		}
+	}
+	return false
+}
+
+// Nodes returns number of 'cache node' in the map.
+func (r *Cache) Nodes() int {
+	return int(atomic.LoadInt32(&r.nodes))
+}
+
+// Size returns sums of 'cache node' size in the map.
+func (r *Cache) Size() int {
+	return int(atomic.LoadInt32(&r.size))
+}
+
+// Capacity returns cache capacity.
+func (r *Cache) Capacity() int {
+	if r.cacher == nil {
+		return 0
+	}
+	return r.cacher.Capacity()
+}
+
+// SetCapacity sets cache capacity.
+func (r *Cache) SetCapacity(capacity int) {
+	if r.cacher != nil {
+		r.cacher.SetCapacity(capacity)
+	}
+}
+
+// Get gets 'cache node' with the given namespace and key.
+// If cache node is not found and setFunc is not nil, Get will atomically creates
+// the 'cache node' by calling setFunc. Otherwise Get will returns nil.
+//
+// The returned 'cache handle' should be released after use by calling Release
+// method.
+func (r *Cache) Get(ns, key uint64, setFunc func() (size int, value Value)) *Handle {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+	if r.closed {
+		return nil
+	}
+
+	hash := murmur32(ns, key, 0xf00)
+	for {
+		h, b := r.getBucket(hash)
+		done, _, n := b.get(r, h, hash, ns, key, setFunc == nil)
+		if done {
+			if n != nil {
+				n.mu.Lock()
+				if n.value == nil {
+					if setFunc == nil {
+						n.mu.Unlock()
+						n.unref()
+						return nil
+					}
+
+					n.size, n.value = setFunc()
+					if n.value == nil {
+						n.size = 0
+						n.mu.Unlock()
+						n.unref()
+						return nil
+					}
+					atomic.AddInt32(&r.size, int32(n.size))
+				}
+				n.mu.Unlock()
+				if r.cacher != nil {
+					r.cacher.Promote(n)
+				}
+				return &Handle{unsafe.Pointer(n)}
+			}
+
+			break
+		}
 	}
 	return nil
 }
 
-func (o *fakeObject) Release() {
-	if !atomic.CompareAndSwapUint32(&o.once, 0, 1) {
+// Delete removes and ban 'cache node' with the given namespace and key.
+// A banned 'cache node' will never inserted into the 'cache tree'. Ban
+// only attributed to the particular 'cache node', so when a 'cache node'
+// is recreated it will not be banned.
+//
+// If onDel is not nil, then it will be executed if such 'cache node'
+// doesn't exist or once the 'cache node' is released.
+//
+// Delete return true is such 'cache node' exist.
+func (r *Cache) Delete(ns, key uint64, onDel func()) bool {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+	if r.closed {
+		return false
+	}
+
+	hash := murmur32(ns, key, 0xf00)
+	for {
+		h, b := r.getBucket(hash)
+		done, _, n := b.get(r, h, hash, ns, key, true)
+		if done {
+			if n != nil {
+				if onDel != nil {
+					n.mu.Lock()
+					n.onDel = append(n.onDel, onDel)
+					n.mu.Unlock()
+				}
+				if r.cacher != nil {
+					r.cacher.Ban(n)
+				}
+				n.unref()
+				return true
+			}
+
+			break
+		}
+	}
+
+	if onDel != nil {
+		onDel()
+	}
+
+	return false
+}
+
+// Evict evicts 'cache node' with the given namespace and key. This will
+// simply call Cacher.Evict.
+//
+// Evict return true is such 'cache node' exist.
+func (r *Cache) Evict(ns, key uint64) bool {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+	if r.closed {
+		return false
+	}
+
+	hash := murmur32(ns, key, 0xf00)
+	for {
+		h, b := r.getBucket(hash)
+		done, _, n := b.get(r, h, hash, ns, key, true)
+		if done {
+			if n != nil {
+				if r.cacher != nil {
+					r.cacher.Evict(n)
+				}
+				n.unref()
+				return true
+			}
+
+			break
+		}
+	}
+
+	return false
+}
+
+// EvictNS evicts 'cache node' with the given namespace. This will
+// simply call Cacher.EvictNS.
+func (r *Cache) EvictNS(ns uint64) {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+	if r.closed {
+		return
+	}
+
+	if r.cacher != nil {
+		r.cacher.EvictNS(ns)
+	}
+}
+
+// EvictAll evicts all 'cache node'. This will simply call Cacher.EvictAll.
+func (r *Cache) EvictAll() {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+	if r.closed {
 		return
 	}
-	if o.fin != nil {
-		o.fin()
-		o.fin = nil
+
+	if r.cacher != nil {
+		r.cacher.EvictAll()
+	}
+}
+
+// Close closes the 'cache map' and releases all 'cache node'.
+func (r *Cache) Close() error {
+	r.mu.Lock()
+	if !r.closed {
+		r.closed = true
+
+		if r.cacher != nil {
+			if err := r.cacher.Close(); err != nil {
+				return err
+			}
+		}
+
+		h := (*mNode)(r.mHead)
+		h.initBuckets()
+
+		for i := range h.buckets {
+			b := (*mBucket)(h.buckets[i])
+			for _, n := range b.node {
+				// Call releaser.
+				if n.value != nil {
+					if r, ok := n.value.(util.Releaser); ok {
+						r.Release()
+					}
+					n.value = nil
+				}
+
+				// Call OnDel.
+				for _, f := range n.onDel {
+					f()
+				}
+			}
+		}
 	}
+	r.mu.Unlock()
+	return nil
+}
+
+// Node is a 'cache node'.
+type Node struct {
+	r *Cache
+
+	hash    uint32
+	ns, key uint64
+
+	mu    sync.Mutex
+	size  int
+	value Value
+
+	ref   int32
+	onDel []func()
+
+	CacheData unsafe.Pointer
+}
+
+// NS returns this 'cache node' namespace.
+func (n *Node) NS() uint64 {
+	return n.ns
+}
+
+// Key returns this 'cache node' key.
+func (n *Node) Key() uint64 {
+	return n.key
+}
+
+// Size returns this 'cache node' size.
+func (n *Node) Size() int {
+	return n.size
+}
+
+// Value returns this 'cache node' value.
+func (n *Node) Value() Value {
+	return n.value
+}
+
+// Ref returns this 'cache node' ref counter.
+func (n *Node) Ref() int32 {
+	return atomic.LoadInt32(&n.ref)
+}
+
+// GetHandle returns an handle for this 'cache node'.
+func (n *Node) GetHandle() *Handle {
+	if atomic.AddInt32(&n.ref, 1) <= 1 {
+		panic("BUG: Node.GetHandle on zero ref")
+	}
+	return &Handle{unsafe.Pointer(n)}
+}
+
+func (n *Node) unref() {
+	if atomic.AddInt32(&n.ref, -1) == 0 {
+		n.r.delete(n)
+	}
+}
+
+func (n *Node) unrefLocked() {
+	if atomic.AddInt32(&n.ref, -1) == 0 {
+		n.r.mu.RLock()
+		if !n.r.closed {
+			n.r.delete(n)
+		}
+		n.r.mu.RUnlock()
+	}
+}
+
+type Handle struct {
+	n unsafe.Pointer // *Node
+}
+
+func (h *Handle) Value() Value {
+	n := (*Node)(atomic.LoadPointer(&h.n))
+	if n != nil {
+		return n.value
+	}
+	return nil
+}
+
+func (h *Handle) Release() {
+	nPtr := atomic.LoadPointer(&h.n)
+	if nPtr != nil && atomic.CompareAndSwapPointer(&h.n, nPtr, nil) {
+		n := (*Node)(nPtr)
+		n.unrefLocked()
+	}
+}
+
+func murmur32(ns, key uint64, seed uint32) uint32 {
+	const (
+		m = uint32(0x5bd1e995)
+		r = 24
+	)
+
+	k1 := uint32(ns >> 32)
+	k2 := uint32(ns)
+	k3 := uint32(key >> 32)
+	k4 := uint32(key)
+
+	k1 *= m
+	k1 ^= k1 >> r
+	k1 *= m
+
+	k2 *= m
+	k2 ^= k2 >> r
+	k2 *= m
+
+	k3 *= m
+	k3 ^= k3 >> r
+	k3 *= m
+
+	k4 *= m
+	k4 ^= k4 >> r
+	k4 *= m
+
+	h := seed
+
+	h *= m
+	h ^= k1
+	h *= m
+	h ^= k2
+	h *= m
+	h ^= k3
+	h *= m
+	h ^= k4
+
+	h ^= h >> 13
+	h *= m
+	h ^= h >> 15
+
+	return h
 }