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package packfile
import (
"gopkg.in/src-d/go-git.v4/plumbing"
)
// ObjectToPack is a representation of an object that is going to be into a
// pack file.
type ObjectToPack struct {
// The main object to pack, it could be any object, including deltas
Object plumbing.EncodedObject
// Base is the object that a delta is based on (it could be also another delta).
// If the main object is not a delta, Base will be null
Base *ObjectToPack
// Original is the object that we can generate applying the delta to
// Base, or the same object as Object in the case of a non-delta
// object.
Original plumbing.EncodedObject
// Depth is the amount of deltas needed to resolve to obtain Original
// (delta based on delta based on ...)
Depth int
// offset in pack when object has been already written, or 0 if it
// has not been written yet
Offset int64
// Information from the original object
resolvedOriginal bool
originalType plumbing.ObjectType
originalSize int64
originalHash plumbing.Hash
}
// newObjectToPack creates a correct ObjectToPack based on a non-delta object
func newObjectToPack(o plumbing.EncodedObject) *ObjectToPack {
return &ObjectToPack{
Object: o,
Original: o,
}
}
// newDeltaObjectToPack creates a correct ObjectToPack for a delta object, based on
// his base (could be another delta), the delta target (in this case called original),
// and the delta Object itself
func newDeltaObjectToPack(base *ObjectToPack, original, delta plumbing.EncodedObject) *ObjectToPack {
return &ObjectToPack{
Object: delta,
Base: base,
Original: original,
Depth: base.Depth + 1,
}
}
// BackToOriginal converts that ObjectToPack to a non-deltified object if it was one
func (o *ObjectToPack) BackToOriginal() {
if o.IsDelta() && o.Original != nil {
o.Object = o.Original
o.Base = nil
o.Depth = 0
}
}
// IsWritten returns if that ObjectToPack was
// already written into the packfile or not
func (o *ObjectToPack) IsWritten() bool {
return o.Offset > 1
}
// MarkWantWrite marks this ObjectToPack as WantWrite
// to avoid delta chain loops
func (o *ObjectToPack) MarkWantWrite() {
o.Offset = 1
}
// WantWrite checks if this ObjectToPack was marked as WantWrite before
func (o *ObjectToPack) WantWrite() bool {
return o.Offset == 1
}
// SetOriginal sets both Original and saves size, type and hash. If object
// is nil Original is set but previous resolved values are kept
func (o *ObjectToPack) SetOriginal(obj plumbing.EncodedObject) {
o.Original = obj
o.SaveOriginalMetadata()
}
// SaveOriginalMetadata saves size, type and hash of Original object
func (o *ObjectToPack) SaveOriginalMetadata() {
if o.Original != nil {
o.originalSize = o.Original.Size()
o.originalType = o.Original.Type()
o.originalHash = o.Original.Hash()
o.resolvedOriginal = true
}
}
// CleanOriginal sets Original to nil
func (o *ObjectToPack) CleanOriginal() {
o.Original = nil
}
func (o *ObjectToPack) Type() plumbing.ObjectType {
if o.Original != nil {
return o.Original.Type()
}
if o.resolvedOriginal {
return o.originalType
}
if o.Base != nil {
return o.Base.Type()
}
if o.Object != nil {
return o.Object.Type()
}
panic("cannot get type")
}
func (o *ObjectToPack) Hash() plumbing.Hash {
if o.Original != nil {
return o.Original.Hash()
}
if o.resolvedOriginal {
return o.originalHash
}
do, ok := o.Object.(plumbing.DeltaObject)
if ok {
return do.ActualHash()
}
panic("cannot get hash")
}
func (o *ObjectToPack) Size() int64 {
if o.Original != nil {
return o.Original.Size()
}
if o.resolvedOriginal {
return o.originalSize
}
do, ok := o.Object.(plumbing.DeltaObject)
if ok {
return do.ActualSize()
}
panic("cannot get ObjectToPack size")
}
func (o *ObjectToPack) IsDelta() bool {
return o.Base != nil
}
func (o *ObjectToPack) SetDelta(base *ObjectToPack, delta plumbing.EncodedObject) {
o.Object = delta
o.Base = base
o.Depth = base.Depth + 1
}
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