switch to go vendoring

vendor/github.com/CiscoM31/godata/compute_parser.go

@@ -0,0 +1,73 @@
+package godata
+
+import (
+	"context"
+	"regexp"
+	"strings"
+)
+
+// The $compute query option must have a value which is a comma separated list of <expression> as <dynamic property name>
+// See https://docs.oasis-open.org/odata/odata/v4.01/os/part2-url-conventions/odata-v4.01-os-part2-url-conventions.html#sec_SystemQueryOptioncompute
+const computeAsSeparator = " as "
+
+// Dynamic property names are restricted to case-insensitive a-z
+var computeFieldRegex = regexp.MustCompile("^[a-zA-Z]+$")
+
+type ComputeItem struct {
+	Tree  *ParseNode // The compute expression parsed as a tree.
+	Field string     // The name of the computed dynamic property.
+}
+
+func ParseComputeString(ctx context.Context, compute string) (*GoDataComputeQuery, error) {
+	items := strings.Split(compute, ",")
+
+	result := make([]*ComputeItem, 0)
+
+	for _, v := range items {
+		v = strings.TrimSpace(v)
+		parts := strings.Split(v, computeAsSeparator)
+		if len(parts) != 2 {
+			return nil, &GoDataError{
+				ResponseCode: 400,
+				Message:      "Invalid $compute query option",
+			}
+		}
+		field := strings.TrimSpace(parts[1])
+		if !computeFieldRegex.MatchString(field) {
+			return nil, &GoDataError{
+				ResponseCode: 400,
+				Message:      "Invalid $compute query option",
+			}
+		}
+
+		if tree, err := GlobalExpressionParser.ParseExpressionString(ctx, parts[0]); err != nil {
+			switch e := err.(type) {
+			case *GoDataError:
+				return nil, &GoDataError{
+					ResponseCode: e.ResponseCode,
+					Message:      "Invalid $compute query option",
+					Cause:        e,
+				}
+			default:
+				return nil, &GoDataError{
+					ResponseCode: 500,
+					Message:      "Invalid $compute query option",
+					Cause:        e,
+				}
+			}
+		} else {
+			if tree == nil {
+				return nil, &GoDataError{
+					ResponseCode: 500,
+					Message:      "Invalid $compute query option",
+				}
+			}
+			result = append(result, &ComputeItem{
+				Tree:  tree.Tree,
+				Field: field,
+			})
+		}
+	}
+
+	return &GoDataComputeQuery{result, compute}, nil
+}