Add docs comments

Signed-off-by: Natalie Arellano <[email protected]>

layout/options.go

@@ -10,54 +10,71 @@ import (
 
 type ImageOption func(*imgutil.ImageOptions)
 
-func FromBaseImagePath(name string) func(*imgutil.ImageOptions) {
-	return func(o *imgutil.ImageOptions) {
-		o.BaseImageRepoName = name
-	}
-}
-
+// FromBaseImage loads the provided image as the manifest, config, and layers for the working image.
+// If the image is not found, it does nothing.
 func FromBaseImage(image v1.Image) func(*imgutil.ImageOptions) {
 	return func(o *imgutil.ImageOptions) {
 		o.BaseImage = image
 	}
 }
 
-func WithConfig(c *v1.Config) func(*imgutil.ImageOptions) {
+// FromBaseImagePath (layout only) loads the image at the provided path as the manifest, config, and layers for the working image.
+// If the image is not found, it does nothing.
+func FromBaseImagePath(name string) func(*imgutil.ImageOptions) {
 	return func(o *imgutil.ImageOptions) {
-		o.Config = c
+		o.BaseImageRepoName = name
 	}
 }
 
+// WithCreatedAt lets a caller set the "created at" timestamp for the working image when saved.
+// If not provided, the default is imgutil.NormalizedDateTime.
 func WithCreatedAt(t time.Time) func(*imgutil.ImageOptions) {
 	return func(o *imgutil.ImageOptions) {
 		o.CreatedAt = t
 	}
 }
 
+// WithConfig lets a caller provided a `config` object for the working image.
+func WithConfig(c *v1.Config) func(*imgutil.ImageOptions) {
+	return func(o *imgutil.ImageOptions) {
+		o.Config = c
+	}
+}
+
+// WithDefaultPlatform provides the default Architecture/OS/OSVersion if no base image is provided,
+// or if the provided image inputs (base and previous) are manifest lists.
 func WithDefaultPlatform(p imgutil.Platform) func(*imgutil.ImageOptions) {
 	return func(o *imgutil.ImageOptions) {
 		o.Platform = p
 	}
 }
 
+// WithHistory if provided will configure the image to preserve history when saved
+// (including any history from the base image if valid).
 func WithHistory() func(*imgutil.ImageOptions) {
 	return func(o *imgutil.ImageOptions) {
 		o.PreserveHistory = true
 	}
 }
 
-func WithPreviousImage(name string) func(*imgutil.ImageOptions) {
+// WithMediaTypes lets a caller set the desired media types for the manifest and config (including layers referenced in the manifest)
+// to be either OCI media types or Docker media types.
+func WithMediaTypes(m imgutil.MediaTypes) func(*imgutil.ImageOptions) {
 	return func(o *imgutil.ImageOptions) {
-		o.PreviousImageRepoName = name
+		o.MediaTypes = m
 	}
 }
 
-func WithMediaTypes(m imgutil.MediaTypes) func(*imgutil.ImageOptions) {
+// WithPreviousImage loads an existing image as the source for reusable layers.
+// Use with ReuseLayer().
+// If the image is not found, it does nothing.
+func WithPreviousImage(name string) func(*imgutil.ImageOptions) {
 	return func(o *imgutil.ImageOptions) {
-		o.MediaTypes = m
+		o.PreviousImageRepoName = name
 	}
 }
 
+// WithoutLayersWhenSaved (layout only) if provided will cause the image to be written without layers in the `blobs` directory.
 func WithoutLayersWhenSaved() func(*imgutil.ImageOptions) {
 	return func(o *imgutil.ImageOptions) {
 		o.WithoutLayers = true