plumbing: add packWindow comments

Author: strib

plumbing/format/packfile/delta_selector.go

@@ -28,8 +28,11 @@ func newDeltaSelector(s storer.EncodedObjectStorer) *deltaSelector {
 	return &deltaSelector{s}
 }
 
-// ObjectsToPack creates a list of ObjectToPack from the hashes provided,
-// creating deltas if it's suitable, using an specific internal logic
+// ObjectsToPack creates a list of ObjectToPack from the hashes
+// provided, creating deltas if it's suitable, using an specific
+// internal logic.  `packWindow` specifies the size of the sliding
+// window used to compare objects for delta compression; 0 turns off
+// delta compression entirely.
 func (dw *deltaSelector) ObjectsToPack(
 	hashes []plumbing.Hash,
 	packWindow uint,

plumbing/format/packfile/encoder.go

@@ -45,8 +45,10 @@ func NewEncoder(w io.Writer, s storer.EncodedObjectStorer, useRefDeltas bool) *E
 	}
 }
 
-// Encode creates a packfile containing all the objects referenced in hashes
-// and writes it to the writer in the Encoder.
+// Encode creates a packfile containing all the objects referenced in
+// hashes and writes it to the writer in the Encoder.  `packWindow`
+// specifies the size of the sliding window used to compare objects
+// for delta compression; 0 turns off delta compression entirely.
 func (e *Encoder) Encode(
 	hashes []plumbing.Hash,
 	packWindow uint,