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authorMáximo Cuadros <mcuadros@gmail.com>2017-02-21 16:08:57 +0100
committerGitHub <noreply@github.com>2017-02-21 16:08:57 +0100
commite26a605c93d8085dfff8e440838fd3c43b63cff6 (patch)
tree7022e74d0fa7a3ab542eaa2df851e7f625e8f1ff /plumbing/cache
parent73855d0a5f617bcda1f33e730f3bc7cf8afbef6c (diff)
parent6e15f9cb0dbac68992eb242282e725784fe72b32 (diff)
downloadgo-git-e26a605c93d8085dfff8e440838fd3c43b63cff6.tar.gz
Merge pull request #278 from ajnavarro/improvement/move-cache-to-plumbing
cache: move package to plumbing
Diffstat (limited to 'plumbing/cache')
-rw-r--r--plumbing/cache/common.go16
-rw-r--r--plumbing/cache/object.go68
-rw-r--r--plumbing/cache/object_test.go85
-rw-r--r--plumbing/cache/queue.go46
4 files changed, 215 insertions, 0 deletions
diff --git a/plumbing/cache/common.go b/plumbing/cache/common.go
new file mode 100644
index 0000000..33fb2bc
--- /dev/null
+++ b/plumbing/cache/common.go
@@ -0,0 +1,16 @@
+package cache
+
+import "srcd.works/go-git.v4/plumbing"
+
+const (
+ Byte = 1 << (iota * 10)
+ KiByte
+ MiByte
+ GiByte
+)
+
+type Object interface {
+ Add(o plumbing.EncodedObject)
+ Get(k plumbing.Hash) plumbing.EncodedObject
+ Clear()
+}
diff --git a/plumbing/cache/object.go b/plumbing/cache/object.go
new file mode 100644
index 0000000..47e390b
--- /dev/null
+++ b/plumbing/cache/object.go
@@ -0,0 +1,68 @@
+package cache
+
+import "srcd.works/go-git.v4/plumbing"
+
+const (
+ initialQueueSize = 20
+ MaxSize = 10 * MiByte
+)
+
+type ObjectFIFO struct {
+ objects map[plumbing.Hash]plumbing.EncodedObject
+ order *queue
+
+ maxSize int64
+ actualSize int64
+}
+
+// NewObjectFIFO returns an Object cache that keeps the newest objects that fit
+// into the specific memory size
+func NewObjectFIFO(size int64) *ObjectFIFO {
+ return &ObjectFIFO{
+ objects: make(map[plumbing.Hash]plumbing.EncodedObject),
+ order: newQueue(initialQueueSize),
+ maxSize: size,
+ }
+}
+
+// Add adds a new object to the cache. If the object size is greater than the
+// cache size, the object is not added.
+func (c *ObjectFIFO) Add(o plumbing.EncodedObject) {
+ // if the size of the object is bigger or equal than the cache size,
+ // skip it
+ if o.Size() >= c.maxSize {
+ return
+ }
+
+ // if the object is into the cache, do not add it again
+ if _, ok := c.objects[o.Hash()]; ok {
+ return
+ }
+
+ // delete the oldest object if cache is full
+ if c.actualSize >= c.maxSize {
+ h := c.order.Pop()
+ o := c.objects[h]
+ if o != nil {
+ c.actualSize -= o.Size()
+ delete(c.objects, h)
+ }
+ }
+
+ c.objects[o.Hash()] = o
+ c.order.Push(o.Hash())
+ c.actualSize += o.Size()
+}
+
+// Get returns an object by his hash. If the object is not found in the cache, it
+// returns nil
+func (c *ObjectFIFO) Get(k plumbing.Hash) plumbing.EncodedObject {
+ return c.objects[k]
+}
+
+// Clear the content of this object cache
+func (c *ObjectFIFO) Clear() {
+ c.objects = make(map[plumbing.Hash]plumbing.EncodedObject)
+ c.order = newQueue(initialQueueSize)
+ c.actualSize = 0
+}
diff --git a/plumbing/cache/object_test.go b/plumbing/cache/object_test.go
new file mode 100644
index 0000000..7d00970
--- /dev/null
+++ b/plumbing/cache/object_test.go
@@ -0,0 +1,85 @@
+package cache
+
+import (
+ "io"
+ "testing"
+
+ "srcd.works/go-git.v4/plumbing"
+
+ . "gopkg.in/check.v1"
+)
+
+func Test(t *testing.T) { TestingT(t) }
+
+type ObjectSuite struct {
+ c *ObjectFIFO
+ aObject plumbing.EncodedObject
+ bObject plumbing.EncodedObject
+ cObject plumbing.EncodedObject
+ dObject plumbing.EncodedObject
+}
+
+var _ = Suite(&ObjectSuite{})
+
+func (s *ObjectSuite) SetUpTest(c *C) {
+ s.aObject = newObject("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", 1*Byte)
+ s.bObject = newObject("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb", 3*Byte)
+ s.cObject = newObject("cccccccccccccccccccccccccccccccccccccccc", 1*Byte)
+ s.dObject = newObject("dddddddddddddddddddddddddddddddddddddddd", 1*Byte)
+
+ s.c = NewObjectFIFO(2 * Byte)
+}
+
+func (s *ObjectSuite) TestAdd_SameObject(c *C) {
+ s.c.Add(s.aObject)
+ c.Assert(s.c.actualSize, Equals, int64(1*Byte))
+ s.c.Add(s.aObject)
+ c.Assert(s.c.actualSize, Equals, int64(1*Byte))
+}
+
+func (s *ObjectSuite) TestAdd_BigObject(c *C) {
+ s.c.Add(s.bObject)
+ c.Assert(s.c.actualSize, Equals, int64(0))
+ c.Assert(len(s.c.objects), Equals, 0)
+}
+
+func (s *ObjectSuite) TestAdd_CacheOverflow(c *C) {
+ s.c.Add(s.aObject)
+ c.Assert(s.c.actualSize, Equals, int64(1*Byte))
+ s.c.Add(s.cObject)
+ c.Assert(len(s.c.objects), Equals, 2)
+ s.c.Add(s.dObject)
+ c.Assert(len(s.c.objects), Equals, 2)
+
+ c.Assert(s.c.Get(s.aObject.Hash()), IsNil)
+ c.Assert(s.c.Get(s.cObject.Hash()), NotNil)
+ c.Assert(s.c.Get(s.dObject.Hash()), NotNil)
+}
+
+func (s *ObjectSuite) TestClear(c *C) {
+ s.c.Add(s.aObject)
+ c.Assert(s.c.actualSize, Equals, int64(1*Byte))
+ s.c.Clear()
+ c.Assert(s.c.actualSize, Equals, int64(0))
+ c.Assert(s.c.Get(s.aObject.Hash()), IsNil)
+}
+
+type dummyObject struct {
+ hash plumbing.Hash
+ size int64
+}
+
+func newObject(hash string, size int64) plumbing.EncodedObject {
+ return &dummyObject{
+ hash: plumbing.NewHash(hash),
+ size: size,
+ }
+}
+
+func (d *dummyObject) Hash() plumbing.Hash { return d.hash }
+func (*dummyObject) Type() plumbing.ObjectType { return plumbing.InvalidObject }
+func (*dummyObject) SetType(plumbing.ObjectType) {}
+func (d *dummyObject) Size() int64 { return d.size }
+func (*dummyObject) SetSize(s int64) {}
+func (*dummyObject) Reader() (io.ReadCloser, error) { return nil, nil }
+func (*dummyObject) Writer() (io.WriteCloser, error) { return nil, nil }
diff --git a/plumbing/cache/queue.go b/plumbing/cache/queue.go
new file mode 100644
index 0000000..8c6d7d3
--- /dev/null
+++ b/plumbing/cache/queue.go
@@ -0,0 +1,46 @@
+package cache
+
+import "srcd.works/go-git.v4/plumbing"
+
+// queue is a basic FIFO queue based on a circular list that resize as needed.
+type queue struct {
+ elements []plumbing.Hash
+ size int
+ head int
+ tail int
+ count int
+}
+
+// newQueue returns a queue with the specified initial size
+func newQueue(size int) *queue {
+ return &queue{
+ elements: make([]plumbing.Hash, size),
+ size: size,
+ }
+}
+
+// Push adds a node to the queue.
+func (q *queue) Push(h plumbing.Hash) {
+ if q.head == q.tail && q.count > 0 {
+ elements := make([]plumbing.Hash, len(q.elements)+q.size)
+ copy(elements, q.elements[q.head:])
+ copy(elements[len(q.elements)-q.head:], q.elements[:q.head])
+ q.head = 0
+ q.tail = len(q.elements)
+ q.elements = elements
+ }
+ q.elements[q.tail] = h
+ q.tail = (q.tail + 1) % len(q.elements)
+ q.count++
+}
+
+// Pop removes and returns a Hash from the queue in first to last order.
+func (q *queue) Pop() plumbing.Hash {
+ if q.count == 0 {
+ return plumbing.ZeroHash
+ }
+ node := q.elements[q.head]
+ q.head = (q.head + 1) % len(q.elements)
+ q.count--
+ return node
+}