Remove deprecated usage of github.com/golang/protobuf/protoc-gen-go/g…

…enerator (#1237)

protoc-gen-swagger/genswagger/BUILD.bazel

@@ -22,7 +22,6 @@ go_library(
         "@com_github_golang_protobuf//descriptor:go_default_library_gen",
         "@com_github_golang_protobuf//jsonpb:go_default_library_gen",
         "@com_github_golang_protobuf//proto:go_default_library",
-        "@com_github_golang_protobuf//protoc-gen-go/generator:go_default_library_gen",
         "@io_bazel_rules_go//proto/wkt:any_go_proto",
         "@io_bazel_rules_go//proto/wkt:compiler_plugin_go_proto",
         "@io_bazel_rules_go//proto/wkt:descriptor_go_proto",

protoc-gen-swagger/genswagger/template.go

@@ -18,7 +18,6 @@ import (
 	"github.com/golang/protobuf/jsonpb"
 	"github.com/golang/protobuf/proto"
 	pbdescriptor "github.com/golang/protobuf/protoc-gen-go/descriptor"
-	gogen "github.com/golang/protobuf/protoc-gen-go/generator"
 	structpb "github.com/golang/protobuf/ptypes/struct"
 	"github.com/grpc-ecosystem/grpc-gateway/v2/protoc-gen-grpc-gateway/descriptor"
 	swagger_options "github.com/grpc-ecosystem/grpc-gateway/v2/protoc-gen-swagger/options"
@@ -1654,7 +1653,7 @@ func isProtoPathMatches(paths []int32, outerPaths []int32, typeName string, type
 // For example, if we are trying to locate comments related to a field named
 // `Address` in a message named `Person`, the path will be:
 //
-//     [4, a, 2, b]
+//	 [4, a, 2, b]
 //
 // While `a` gets determined by the order in which the messages appear in
 // the proto file, and `b` is the field index specified in the proto
@@ -1969,7 +1968,7 @@ func lowerCamelCase(fieldName string, fields []*descriptor.Field, msgs []*descri
 }
 
 func doCamelCase(input string) string {
-	parameterString := gogen.CamelCase(input)
+	parameterString := camelCase(input)
 	builder := &strings.Builder{}
 	builder.WriteString(strings.ToLower(string(parameterString[0])))
 	builder.WriteString(parameterString[1:])
@@ -1988,3 +1987,65 @@ func getReservedJSONName(fieldName string, messageNameToFieldsToJSONName map[str
 	fieldNames := strings.Split(fieldName, ".")
 	return getReservedJSONName(strings.Join(fieldNames[1:], "."), messageNameToFieldsToJSONName, fieldNameToType)
 }
+
+// CamelCase returns the CamelCased name.
+//
+// This was moved from the now deprecated github.com/golang/protobuf/protoc-gen-go/generator package
+//
+// If there is an interior underscore followed by a lower case letter,
+// drop the underscore and convert the letter to upper case.
+// There is a remote possibility of this rewrite causing a name collision,
+// but it's so remote we're prepared to pretend it's nonexistent - since the
+// C++ generator lowercases names, it's extremely unlikely to have two fields
+// with different capitalizations.
+// In short, _my_field_name_2 becomes XMyFieldName_2.
+func camelCase(s string) string {
+	if s == "" {
+		return ""
+	}
+	t := make([]byte, 0, 32)
+	i := 0
+	if s[0] == '_' {
+		// Need a capital letter; drop the '_'.
+		t = append(t, 'X')
+		i++
+	}
+	// Invariant: if the next letter is lower case, it must be converted
+	// to upper case.
+	// That is, we process a word at a time, where words are marked by _ or
+	// upper case letter. Digits are treated as words.
+	for ; i < len(s); i++ {
+		c := s[i]
+		if c == '_' && i+1 < len(s) && isASCIILower(s[i+1]) {
+			continue // Skip the underscore in s.
+		}
+		if isASCIIDigit(c) {
+			t = append(t, c)
+			continue
+		}
+		// Assume we have a letter now - if not, it's a bogus identifier.
+		// The next word is a sequence of characters that must start upper case.
+		if isASCIILower(c) {
+			c ^= ' ' // Make it a capital letter.
+		}
+		t = append(t, c) // Guaranteed not lower case.
+		// Accept lower case sequence that follows.
+		for i+1 < len(s) && isASCIILower(s[i+1]) {
+			i++
+			t = append(t, s[i])
+		}
+	}
+	return string(t)
+}
+
+// And now lots of helper functions.
+
+// Is c an ASCII lower-case letter?
+func isASCIILower(c byte) bool {
+	return 'a' <= c && c <= 'z'
+}
+
+// Is c an ASCII digit?
+func isASCIIDigit(c byte) bool {
+	return '0' <= c && c <= '9'
+}