Add package for printing starlark formatted data

Bug: 216168792
Test: build/bazel/ci/bp2build.sh
Change-Id: I3a06b19396f7ffe1c638042cda7e731dd840f1d6

starlark_fmt/format.go

@@ -0,0 +1,96 @@
+// Copyright 2022 Google Inc. All rights reserved.
+//
+// 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 starlark_fmt
+
+import (
+	"fmt"
+	"sort"
+	"strings"
+)
+
+const (
+	indent = 4
+)
+
+// Indention returns an indent string of the specified level.
+func Indention(level int) string {
+	if level < 0 {
+		panic(fmt.Errorf("indent level cannot be less than 0, but got %d", level))
+	}
+	return strings.Repeat(" ", level*indent)
+}
+
+// PrintBool returns a Starlark compatible bool string.
+func PrintBool(item bool) string {
+	return strings.Title(fmt.Sprintf("%t", item))
+}
+
+// PrintsStringList returns a Starlark-compatible string of a list of Strings/Labels.
+func PrintStringList(items []string, indentLevel int) string {
+	return PrintList(items, indentLevel, `"%s"`)
+}
+
+// PrintList returns a Starlark-compatible string of list formmated as requested.
+func PrintList(items []string, indentLevel int, formatString string) string {
+	if len(items) == 0 {
+		return "[]"
+	} else if len(items) == 1 {
+		return fmt.Sprintf("["+formatString+"]", items[0])
+	}
+	list := make([]string, 0, len(items)+2)
+	list = append(list, "[")
+	innerIndent := Indention(indentLevel + 1)
+	for _, item := range items {
+		list = append(list, fmt.Sprintf(`%s`+formatString+`,`, innerIndent, item))
+	}
+	list = append(list, Indention(indentLevel)+"]")
+	return strings.Join(list, "\n")
+}
+
+// PrintStringListDict returns a Starlark-compatible string formatted as dictionary with
+// string keys and list of string values.
+func PrintStringListDict(dict map[string][]string, indentLevel int) string {
+	formattedValueDict := make(map[string]string, len(dict))
+	for k, v := range dict {
+		formattedValueDict[k] = PrintStringList(v, indentLevel+1)
+	}
+	return PrintDict(formattedValueDict, indentLevel)
+}
+
+// PrintBoolDict returns a starlark-compatible string containing a dictionary with string keys and
+// values printed with no additional formatting.
+func PrintBoolDict(dict map[string]bool, indentLevel int) string {
+	formattedValueDict := make(map[string]string, len(dict))
+	for k, v := range dict {
+		formattedValueDict[k] = PrintBool(v)
+	}
+	return PrintDict(formattedValueDict, indentLevel)
+}
+
+// PrintDict returns a starlark-compatible string containing a dictionary with string keys and
+// values printed with no additional formatting.
+func PrintDict(dict map[string]string, indentLevel int) string {
+	if len(dict) == 0 {
+		return "{}"
+	}
+	items := make([]string, 0, len(dict))
+	for k, v := range dict {
+		items = append(items, fmt.Sprintf(`%s"%s": %s,`, Indention(indentLevel+1), k, v))
+	}
+	sort.Strings(items)
+	return fmt.Sprintf(`{
+%s
+%s}`, strings.Join(items, "\n"), Indention(indentLevel))
+}