Initial QSfera import

Server/vendor/github.com/open-policy-agent/opa/internal/strings/strings.go

@@ -0,0 +1,82 @@
+// Copyright 2021 The OPA Authors.  All rights reserved.
+// Use of this source code is governed by an Apache2
+// license that can be found in the LICENSE file.
+
+// Package strings contains helpers to perform string manipulation
+package strings
+
+import (
+	"path/filepath"
+	"strings"
+
+	"github.com/open-policy-agent/opa/internal/lcss"
+)
+
+// TruncateFilePaths truncates the given file paths to conform to the given
+// "ideal" width and returns the shortened paths by replacing the middle parts of paths
+// with "...", ex: bundle1/.../a/b/policy.rego
+func TruncateFilePaths(maxIdealWidth, maxWidth int, path ...string) (map[string]string, int) {
+	canShorten := make([][]byte, 0, len(path))
+
+	for _, p := range path {
+		canShorten = append(canShorten, []byte(getPathFromFirstSeparator(p)))
+	}
+
+	// Find the longest common path segment
+	var lcs string
+	if len(canShorten) > 1 {
+		lcs = string(lcss.LongestCommonSubstring(canShorten...))
+	} else {
+		lcs = string(canShorten[0])
+	}
+
+	// Don't just swap in the full LCSS, trim it down to be the least amount of
+	// characters to reach our "ideal" width boundary giving as much
+	// detail as possible without going too long.
+	diff := maxIdealWidth - (maxWidth - len(lcs) + 3)
+	if diff > 0 {
+		if diff > len(lcs) {
+			lcs = ""
+		} else {
+			// Favor data on the right hand side of the path
+			lcs = lcs[:len(lcs)-diff]
+		}
+	}
+
+	result := map[string]string{}
+	for _, p := range path {
+		result[p] = p
+	}
+
+	longestLocation := maxWidth
+
+	// Swap in "..." for the longest common path, but if it makes things better
+	if len(lcs) > 3 {
+		for path := range result {
+			result[path] = strings.Replace(path, lcs, "...", 1)
+		}
+
+		// Drop the overall length down to match our substitution
+		longestLocation -= (len(lcs) - 3)
+	}
+
+	return result, longestLocation
+}
+
+func Truncate(str string, maxWidth int) string {
+	if len(str) <= maxWidth {
+		return str
+	}
+
+	return str[:maxWidth-3] + "..."
+}
+
+func getPathFromFirstSeparator(path string) string {
+	s := filepath.Dir(path)
+	s = strings.TrimPrefix(s, string(filepath.Separator))
+	firstSlash := strings.IndexRune(s, filepath.Separator)
+	if firstSlash > 0 {
+		return s[firstSlash+1:]
+	}
+	return s
+}