1 files changed, 50 insertions, 0 deletions
diff --git a/vendor/go.opencensus.io/internal/sanitize.go b/vendor/go.opencensus.io/internal/sanitize.go
new file mode 100644
index 000000000..de8ccf236
--- /dev/null
+++ b/vendor/go.opencensus.io/internal/sanitize.go
@@ -0,0 +1,50 @@
+// Copyright 2017, OpenCensus Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package internal
+
+import (
+	"strings"
+	"unicode"
+)
+
+const labelKeySizeLimit = 100
+
+// Sanitize returns a string that is trunacated to 100 characters if it's too
+// long, and replaces non-alphanumeric characters to underscores.
+func Sanitize(s string) string {
+	if len(s) == 0 {
+		return s
+	}
+	if len(s) > labelKeySizeLimit {
+		s = s[:labelKeySizeLimit]
+	}
+	s = strings.Map(sanitizeRune, s)
+	if unicode.IsDigit(rune(s[0])) {
+		s = "key_" + s
+	}
+	if s[0] == '_' {
+		s = "key" + s
+	}
+	return s
+}
+
+// converts anything that is not a letter or digit to an underscore
+func sanitizeRune(r rune) rune {
+	if unicode.IsLetter(r) || unicode.IsDigit(r) {
+		return r
+	}
+	// Everything else turns into an underscore
+	return '_'
+}