Initial QSfera import

Server/vendor/github.com/CiscoM31/godata/search_parser.go

@@ -0,0 +1,59 @@
+package godata
+
+import "context"
+
+type SearchTokenType int
+
+func (s SearchTokenType) Value() int {
+	return (int)(s)
+}
+
+const (
+	SearchTokenLiteral SearchTokenType = iota
+	SearchTokenOpenParen
+	SearchTokenCloseParen
+	SearchTokenOp
+	SearchTokenWhitespace
+)
+
+var GlobalSearchTokenizer = SearchTokenizer()
+var GlobalSearchParser = SearchParser()
+
+// Convert an input string from the $filter part of the URL into a parse
+// tree that can be used by providers to create a response.
+func ParseSearchString(ctx context.Context, filter string) (*GoDataSearchQuery, error) {
+	tokens, err := GlobalSearchTokenizer.Tokenize(ctx, filter)
+	if err != nil {
+		return nil, err
+	}
+	postfix, err := GlobalSearchParser.InfixToPostfix(ctx, tokens)
+	if err != nil {
+		return nil, err
+	}
+	tree, err := GlobalSearchParser.PostfixToTree(ctx, postfix)
+	if err != nil {
+		return nil, err
+	}
+	return &GoDataSearchQuery{tree, filter}, nil
+}
+
+// Create a tokenizer capable of tokenizing filter statements
+func SearchTokenizer() *Tokenizer {
+	t := Tokenizer{}
+	t.Add("^\\\"[^\\\"]+\\\"", SearchTokenLiteral)
+	t.Add("^\\(", SearchTokenOpenParen)
+	t.Add("^\\)", SearchTokenCloseParen)
+	t.Add("^(OR|AND|NOT)", SearchTokenOp)
+	t.Add("^[\\w]+", SearchTokenLiteral)
+	t.Ignore("^ ", SearchTokenWhitespace)
+
+	return &t
+}
+
+func SearchParser() *Parser {
+	parser := EmptyParser()
+	parser.DefineOperator("NOT", 1, OpAssociationNone, 3)
+	parser.DefineOperator("AND", 2, OpAssociationLeft, 2)
+	parser.DefineOperator("OR", 2, OpAssociationLeft, 1)
+	return parser
+}