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- // Copyright 2016 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 android
- import (
- "fmt"
- "strings"
- "unicode"
- "github.com/google/blueprint/proptools"
- )
- // ExpandNinjaEscaped substitutes $() variables in a string
- // $(var) is passed to mapping(var), which should return the expanded value, a bool for whether the result should
- // be left unescaped when using in a ninja value (generally false, true if the expanded value is a ninja variable like
- // '${in}'), and an error.
- // $$ is converted to $, which is escaped back to $$.
- func ExpandNinjaEscaped(s string, mapping func(string) (string, bool, error)) (string, error) {
- return expand(s, true, mapping)
- }
- // Expand substitutes $() variables in a string
- // $(var) is passed to mapping(var), which should return the expanded value and an error.
- // $$ is converted to $.
- func Expand(s string, mapping func(string) (string, error)) (string, error) {
- return expand(s, false, func(s string) (string, bool, error) {
- s, err := mapping(s)
- return s, false, err
- })
- }
- func expand(s string, ninjaEscape bool, mapping func(string) (string, bool, error)) (string, error) {
- // based on os.Expand
- buf := make([]byte, 0, 2*len(s))
- i := 0
- for j := 0; j < len(s); j++ {
- if s[j] == '$' {
- if j+1 >= len(s) {
- return "", fmt.Errorf("expected character after '$'")
- }
- buf = append(buf, s[i:j]...)
- value, ninjaVariable, w, err := getMapping(s[j+1:], mapping)
- if err != nil {
- return "", err
- }
- if !ninjaVariable && ninjaEscape {
- value = proptools.NinjaEscape(value)
- }
- buf = append(buf, value...)
- j += w
- i = j + 1
- }
- }
- return string(buf) + s[i:], nil
- }
- func getMapping(s string, mapping func(string) (string, bool, error)) (string, bool, int, error) {
- switch s[0] {
- case '(':
- // Scan to closing brace
- for i := 1; i < len(s); i++ {
- if s[i] == ')' {
- ret, ninjaVariable, err := mapping(strings.TrimSpace(s[1:i]))
- return ret, ninjaVariable, i + 1, err
- }
- }
- return "", false, len(s), fmt.Errorf("missing )")
- case '$':
- return "$", false, 1, nil
- default:
- i := strings.IndexFunc(s, unicode.IsSpace)
- if i == 0 {
- return "", false, 0, fmt.Errorf("unexpected character '%c' after '$'", s[0])
- } else if i == -1 {
- i = len(s)
- }
- return "", false, 0, fmt.Errorf("expected '(' after '$', did you mean $(%s)?", s[:i])
- }
- }
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