Change BufferPool to an interface.

fuse/api.go

@@ -13,7 +13,7 @@ import (
 // Typically, each call happens in its own goroutine, so take care to
 // make the file system thread-safe.
 //
-// Include DefaultFileSystem to provide default null implementation of
+// Include DefaultFileSystem to provide a default null implementation of
 // required methods.
 type FileSystem interface {
 	// Attributes
@@ -69,7 +69,7 @@ type FileSystem interface {
 //
 // TODO - should File be thread safe?
 type File interface {
-	Read(*ReadIn, *BufferPool) ([]byte, Status)
+	Read(*ReadIn, BufferPool) ([]byte, Status)
 	Write(*WriteIn, []byte) (written uint32, code Status)
 	Truncate(size uint64) Status
 
@@ -137,7 +137,7 @@ type RawFileSystem interface {
 	// File handling.
 	Create(header *InHeader, input *CreateIn, name string) (flags uint32, handle uint64, out *EntryOut, code Status)
 	Open(header *InHeader, input *OpenIn) (flags uint32, handle uint64, status Status)
-	Read(*ReadIn, *BufferPool) ([]byte, Status)
+	Read(*ReadIn, BufferPool) ([]byte, Status)
 
 	Release(header *InHeader, input *ReleaseIn)
 	Write(*WriteIn, []byte) (written uint32, code Status)

fuse/bufferpool.go

@@ -9,10 +9,30 @@ import (
 
 var _ = log.Println
 
+type BufferPool interface {
+	AllocBuffer(size uint32) []byte
+	FreeBuffer(slice []byte)
+}
+
+type GcBufferPool struct {
+}
+
+// NewGcBufferPool is just a fallback to the standard allocation routines. 
+func NewGcBufferPool() *GcBufferPool {
+	return &GcBufferPool{}
+}
+
+func (me *GcBufferPool) AllocBuffer(size uint32) []byte {
+	return make([]byte, size)
+}
+
+func (me *GcBufferPool) FreeBuffer(slice []byte) {
+}
+
 // BufferPool implements a pool of buffers that returns slices with
 // capacity (2^e * PAGESIZE) for e=0,1,...  which have possibly been
 // used, and may contain random contents.
-type BufferPool struct {
+type BufferPoolImpl struct {
 	lock sync.Mutex
 
 	// For each exponent a list of slice pointers.
@@ -41,14 +61,14 @@ func IntToExponent(z int) uint {
 	return exp
 }
 
-func NewBufferPool() *BufferPool {
-	bp := new(BufferPool)
+func NewBufferPool() *BufferPoolImpl {
+	bp := new(BufferPoolImpl)
 	bp.buffersByExponent = make([][][]byte, 0, 8)
 	bp.outstandingBuffers = make(map[uintptr]uint)
 	return bp
 }
 
-func (me *BufferPool) String() string {
+func (me *BufferPoolImpl) String() string {
 	me.lock.Lock()
 	defer me.lock.Unlock()
 	s := fmt.Sprintf("created: %v\noutstanding %v\n",
@@ -59,7 +79,7 @@ func (me *BufferPool) String() string {
 	return s
 }
 
-func (me *BufferPool) getBuffer(exponent uint) []byte {
+func (me *BufferPoolImpl) getBuffer(exponent uint) []byte {
 	if len(me.buffersByExponent) <= int(exponent) {
 		return nil
 	}
@@ -73,7 +93,7 @@ func (me *BufferPool) getBuffer(exponent uint) []byte {
 	return result
 }
 
-func (me *BufferPool) addBuffer(slice []byte, exp uint) {
+func (me *BufferPoolImpl) addBuffer(slice []byte, exp uint) {
 	for len(me.buffersByExponent) <= int(exp) {
 		me.buffersByExponent = append(me.buffersByExponent, make([][]byte, 0))
 	}
@@ -82,7 +102,7 @@ func (me *BufferPool) addBuffer(slice []byte, exp uint) {
 
 // AllocBuffer creates a buffer of at least the given size. After use,
 // it should be deallocated with FreeBuffer().
-func (me *BufferPool) AllocBuffer(size uint32) []byte {
+func (me *BufferPoolImpl) AllocBuffer(size uint32) []byte {
 	sz := int(size)
 	if sz < PAGESIZE {
 		sz = PAGESIZE
@@ -119,7 +139,7 @@ func (me *BufferPool) AllocBuffer(size uint32) []byte {
 // FreeBuffer takes back a buffer if it was allocated through
 // AllocBuffer.  It is not an error to call FreeBuffer() on a slice
 // obtained elsewhere.
-func (me *BufferPool) FreeBuffer(slice []byte) {
+func (me *BufferPoolImpl) FreeBuffer(slice []byte) {
 	if slice == nil {
 		return
 	}

fuse/default.go

@@ -100,7 +100,7 @@ func (me *DefaultRawFileSystem) OpenDir(header *InHeader, input *OpenIn) (flags
 	return 0, 0, ENOSYS
 }
 
-func (me *DefaultRawFileSystem) Read(*ReadIn, *BufferPool) ([]byte, Status) {
+func (me *DefaultRawFileSystem) Read(*ReadIn, BufferPool) ([]byte, Status) {
 	return nil, ENOSYS
 }
 
@@ -137,7 +137,7 @@ func (me *DefaultRawFileSystem) Ioctl(header *InHeader, input *IoctlIn) (output
 ////////////////////////////////////////////////////////////////
 //  DefaultFile
 
-func (me *DefaultFile) Read(*ReadIn, *BufferPool) ([]byte, Status) {
+func (me *DefaultFile) Read(*ReadIn, BufferPool) ([]byte, Status) {
 	return []byte(""), ENOSYS
 }
 

fuse/files.go

@@ -18,7 +18,7 @@ func NewReadOnlyFile(data []byte) *ReadOnlyFile {
 	return f
 }
 
-func (me *ReadOnlyFile) Read(input *ReadIn, bp *BufferPool) ([]byte, Status) {
+func (me *ReadOnlyFile) Read(input *ReadIn, bp BufferPool) ([]byte, Status) {
 	end := int(input.Offset) + int(input.Size)
 	if end > len(me.data) {
 		end = len(me.data)
@@ -38,7 +38,7 @@ func NewDevNullFile() *DevNullFile {
 	return new(DevNullFile)
 }
 
-func (me *DevNullFile) Read(input *ReadIn, bp *BufferPool) ([]byte, Status) {
+func (me *DevNullFile) Read(input *ReadIn, bp BufferPool) ([]byte, Status) {
 	return []byte{}, OK
 }
 
@@ -63,7 +63,7 @@ type LoopbackFile struct {
 	DefaultFile
 }
 
-func (me *LoopbackFile) Read(input *ReadIn, buffers *BufferPool) ([]byte, Status) {
+func (me *LoopbackFile) Read(input *ReadIn, buffers BufferPool) ([]byte, Status) {
 	slice := buffers.AllocBuffer(input.Size)
 
 	n, err := me.file.ReadAt(slice, int64(input.Offset))

fuse/fsetattr_test.go

@@ -17,7 +17,7 @@ type MutableDataFile struct {
 	GetAttrCalled bool
 }
 
-func (me *MutableDataFile) Read(r *ReadIn, bp *BufferPool) ([]byte, Status) {
+func (me *MutableDataFile) Read(r *ReadIn, bp BufferPool) ([]byte, Status) {
 	return me.data[r.Offset : r.Offset+uint64(r.Size)], OK
 }
 

fuse/fuse.go

@@ -29,7 +29,7 @@ type MountState struct {
 	Debug bool
 
 	// For efficient reads and writes.
-	buffers *BufferPool
+	buffers *BufferPoolImpl
 
 	*LatencyMap
 

fuse/lockingfs.go

@@ -274,7 +274,7 @@ func (me *LockingRawFileSystem) ReleaseDir(header *InHeader, h *ReleaseIn) {
 	me.RawFileSystem.ReleaseDir(header, h)
 }
 
-func (me *LockingRawFileSystem) Read(input *ReadIn, bp *BufferPool) ([]byte, Status) {
+func (me *LockingRawFileSystem) Read(input *ReadIn, bp BufferPool) ([]byte, Status) {
 	defer me.locked()()
 	return me.RawFileSystem.Read(input, bp)
 }

fuse/pathops.go

@@ -466,7 +466,7 @@ func (me *FileSystemConnector) Write(input *WriteIn, data []byte) (written uint3
 	return f.Write(input, data)
 }
 
-func (me *FileSystemConnector) Read(input *ReadIn, bp *BufferPool) ([]byte, Status) {
+func (me *FileSystemConnector) Read(input *ReadIn, bp BufferPool) ([]byte, Status) {
 	f, _, n := me.getFile(input.Fh)
 	if me.Debug {
 		me.fileDebug(input.Fh, n)

fuse/timingrawfs.go

@@ -141,7 +141,7 @@ func (me *TimingRawFileSystem) Release(header *InHeader, input *ReleaseIn) {
 	me.RawFileSystem.Release(header, input)
 }
 
-func (me *TimingRawFileSystem) Read(input *ReadIn, bp *BufferPool) ([]byte, Status) {
+func (me *TimingRawFileSystem) Read(input *ReadIn, bp BufferPool) ([]byte, Status) {
 	defer me.startTimer("Read")()
 	return me.RawFileSystem.Read(input, bp)
 }