Reorganize errors

common/errors/errors.go

@@ -0,0 +1,41 @@
+package errors
+
+import (
+	"fmt"
+
+	"gemini-grc/errors"
+)
+
+// HostError is an error encountered while
+// visiting a host, and should be recorded
+// to the snapshot.
+type HostError struct {
+	Err error
+}
+
+func (e *HostError) Error() string {
+	return e.Err.Error()
+}
+
+func (e *HostError) Unwrap() error {
+	return e.Err
+}
+
+func NewHostError(err error) error {
+	return &HostError{Err: err}
+}
+
+func IsHostError(err error) bool {
+	if err == nil {
+		return false
+	}
+	var asError *HostError
+	return errors.As(err, &asError)
+}
+
+// Sentinel errors used for their string message primarily.
+// Do not use them by themselves, to be embedded to HostError.
+var (
+	ErrBlacklistMatch = fmt.Errorf("black list match")
+	ErrRobotsMatch    = fmt.Errorf("robots match")
+)

common/errors/errors_test.go

@@ -0,0 +1,38 @@
+package errors_test
+
+import (
+	"errors"
+	"fmt"
+	"testing"
+
+	"gemini-grc/gemini"
+)
+
+func TestErrGemini(t *testing.T) {
+	t.Parallel()
+	err := gemini.NewGeminiError(50, "50 server error")
+	if !errors.As(err, new(*gemini.GeminiError)) {
+		t.Errorf("TestErrGemini fail")
+	}
+}
+
+func TestErrGeminiWrapped(t *testing.T) {
+	t.Parallel()
+	err := gemini.NewGeminiError(50, "50 server error")
+	errWrapped := fmt.Errorf("%w wrapped", err)
+	if !errors.As(errWrapped, new(*gemini.GeminiError)) {
+		t.Errorf("TestErrGeminiWrapped fail")
+	}
+}
+
+func TestIsGeminiError(t *testing.T) {
+	t.Parallel()
+	err1 := gemini.NewGeminiError(50, "50 server error")
+	if !gemini.IsGeminiError(err1) {
+		t.Errorf("TestGeminiError fail #1")
+	}
+	wrappedErr1 := fmt.Errorf("wrapped %w", err1)
+	if !gemini.IsGeminiError(wrappedErr1) {
+		t.Errorf("TestGeminiError fail #2")
+	}
+}