151 lines
2.8 KiB
Go
151 lines
2.8 KiB
Go
package layer
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import (
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"io"
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"sync"
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"github.com/docker/docker/pkg/archive"
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)
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type mountedLayer struct {
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name string
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mountID string
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initID string
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parent *roLayer
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layerStore *layerStore
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references map[RWLayer]*referencedRWLayer
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}
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func (ml *mountedLayer) cacheParent() string {
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if ml.initID != "" {
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return ml.initID
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}
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if ml.parent != nil {
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return ml.parent.cacheID
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}
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return ""
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}
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func (ml *mountedLayer) TarStream() (io.ReadCloser, error) {
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archiver, err := ml.layerStore.driver.Diff(ml.mountID, ml.cacheParent())
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if err != nil {
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return nil, err
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}
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return archiver, nil
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}
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func (ml *mountedLayer) Name() string {
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return ml.name
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}
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func (ml *mountedLayer) Parent() Layer {
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if ml.parent != nil {
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return ml.parent
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}
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// Return a nil interface instead of an interface wrapping a nil
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// pointer.
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return nil
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}
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func (ml *mountedLayer) Mount(mountLabel string) (string, error) {
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return ml.layerStore.driver.Get(ml.mountID, mountLabel)
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}
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func (ml *mountedLayer) Unmount() error {
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return ml.layerStore.driver.Put(ml.mountID)
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}
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func (ml *mountedLayer) Size() (int64, error) {
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return ml.layerStore.driver.DiffSize(ml.mountID, ml.cacheParent())
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}
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func (ml *mountedLayer) Changes() ([]archive.Change, error) {
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return ml.layerStore.driver.Changes(ml.mountID, ml.cacheParent())
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}
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func (ml *mountedLayer) Metadata() (map[string]string, error) {
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return ml.layerStore.driver.GetMetadata(ml.mountID)
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}
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func (ml *mountedLayer) getReference() RWLayer {
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ref := &referencedRWLayer{
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mountedLayer: ml,
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}
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ml.references[ref] = ref
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return ref
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}
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func (ml *mountedLayer) hasReferences() bool {
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return len(ml.references) > 0
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}
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func (ml *mountedLayer) deleteReference(ref RWLayer) error {
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rl, ok := ml.references[ref]
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if !ok {
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return ErrLayerNotRetained
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}
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if err := rl.release(); err != nil {
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return err
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}
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delete(ml.references, ref)
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return nil
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}
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func (ml *mountedLayer) retakeReference(r RWLayer) {
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if ref, ok := r.(*referencedRWLayer); ok {
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ref.activityCount = 0
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ml.references[ref] = ref
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}
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}
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type referencedRWLayer struct {
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*mountedLayer
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activityL sync.Mutex
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activityCount int
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}
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func (rl *referencedRWLayer) release() error {
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rl.activityL.Lock()
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defer rl.activityL.Unlock()
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if rl.activityCount > 0 {
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return ErrActiveMount
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}
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rl.activityCount = -1
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return nil
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}
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func (rl *referencedRWLayer) Mount(mountLabel string) (string, error) {
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rl.activityL.Lock()
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defer rl.activityL.Unlock()
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if rl.activityCount == -1 {
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return "", ErrLayerNotRetained
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}
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rl.activityCount++
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return rl.mountedLayer.Mount(mountLabel)
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}
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func (rl *referencedRWLayer) Unmount() error {
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rl.activityL.Lock()
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defer rl.activityL.Unlock()
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if rl.activityCount == 0 {
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return ErrNotMounted
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}
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if rl.activityCount == -1 {
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return ErrLayerNotRetained
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}
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rl.activityCount--
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return rl.mountedLayer.Unmount()
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}
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