doc: refactor comments

Signed-off-by: Binbin Li <[email protected]>

signature/envelope.go

@@ -23,17 +23,18 @@ type Envelope interface {
 // NewEnvelopeFunc defines a function to create a new Envelope.
 type NewEnvelopeFunc func() Envelope
 
-// ParseEnvelopeFunc defines a function to create a new Envelope by given
-// envelope bytes.
+// ParseEnvelopeFunc defines a function that takes envelope bytes to create
+// an Envelope.
 type ParseEnvelopeFunc func([]byte) (Envelope, error)
 
-// envelopeFunc wraps functions to create new envelopes
+// envelopeFunc wraps functions to create and parsenew envelopes.
 type envelopeFunc struct {
 	newFunc   NewEnvelopeFunc
 	parseFunc ParseEnvelopeFunc
 }
 
-// envelopeFuncs maps envelope media type to corresponding constructors
+// envelopeFuncs maps envelope media type to corresponding constructors and 
+// parsers.
 var envelopeFuncs = make(map[string]envelopeFunc)
 
 // RegisterEnvelopeType registers newFunc and parseFunc for the given mediaType.

signature/internal/base/envelope.go

@@ -42,7 +42,7 @@ func (e *Envelope) Sign(req *signature.SignRequest) ([]byte, error) {
 //
 // Reference: https://github.com/notaryproject/notaryproject/blob/main/trust-store-trust-policy-specification.md#steps
 func (e *Envelope) Verify() (*signature.Payload, *signature.SignerInfo, error) {
-	// validation before the core verify process
+	// validation before the core verify process.
 	if len(e.Raw) == 0 {
 		return nil, nil, &signature.MalformedSignatureError{}
 	}
@@ -51,13 +51,13 @@ func (e *Envelope) Verify() (*signature.Payload, *signature.SignerInfo, error) {
 		return nil, nil, err
 	}
 
-	// core verify process
+	// core verify process.
 	payload, signerInfo, err := e.Envelope.Verify()
 	if err != nil {
 		return nil, nil, err
 	}
 
-	// validation after the core verify process
+	// validation after the core verify process.
 	if err = validatePayload(payload); err != nil {
 		return nil, nil, err
 	}

signature/types.go

@@ -39,7 +39,7 @@ type SignedAttributes struct {
 // Reference: https://github.com/notaryproject/notaryproject/blob/main/signature-specification.md#unsigned-attributes
 type UnsignedAttributes struct {
 	// SigningAgent provides the identifier of the software (e.g. Notation) that
-	// produced the signature on behalf of the user.
+	// produces the signature on behalf of the user.
 	SigningAgent string
 }