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// Copyright 2015 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
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.
package common
import (
// This file supports globbing source files in Blueprints files.
// The file needs to be regenerated any time a file matching the glob is added
// or removed. The naive solution is to have the file depend on all the
// traversed directories, but this will cause the regeneration step to run every time a
// non-matching file is added to a traversed directory, including backup files created by
// editors.
// The solution implemented here optimizes out regenerations when the directory modifications
// don't match the glob by having the file depend on an intermedate file that
// is only updated when a file matching the glob is added or removed. The intermediate file
// depends on the traversed directories via a depfile. The depfile is used to avoid build
// errors if a directory is deleted - a direct dependency on the deleted directory would result
// in a build failure with a "missing and no known rule to make it" error.
var (
globCmd = filepath.Join("${bootstrap.BinDir}", "soong_glob")
// globRule rule traverses directories to produce a list of files that match $glob
// and writes it to $out if it has changed, and writes the directories to $out.d
globRule = pctx.StaticRule("globRule",
Command: fmt.Sprintf(`%s -o $out $excludes "$glob"`, globCmd),
CommandDeps: []string{globCmd},
Description: "glob $glob",
Restat: true,
Deps: blueprint.DepsGCC,
Depfile: "$out.d",
"glob", "excludes")
func hasGlob(in []string) bool {
for _, s := range in {
if glob.IsGlob(s) {
return true
return false
// The subset of ModuleContext and SingletonContext needed by Glob
type globContext interface {
Build(pctx blueprint.PackageContext, params blueprint.BuildParams)
AddNinjaFileDeps(deps ...string)
func Glob(ctx globContext, outDir string, globPattern string, excludes []string) ([]string, error) {
fileListFile := filepath.Join(outDir, "glob", globToString(globPattern)+".glob")
depFile := fileListFile + ".d"
// Get a globbed file list, and write out fileListFile and depFile
files, err := glob.GlobWithDepFile(globPattern, fileListFile, depFile, excludes)
if err != nil {
return nil, err
GlobRule(ctx, globPattern, excludes, fileListFile, depFile)
// Make depend on the fileListFile
return files, nil
func GlobRule(ctx globContext, globPattern string, excludes []string,
fileListFile, depFile string) {
// Create a rule to rebuild fileListFile if a directory in depFile changes. fileListFile
// will only be rewritten if it has changed, preventing unnecesary regenerations.
ctx.Build(pctx, blueprint.BuildParams{
Rule: globRule,
Outputs: []string{fileListFile},
Args: map[string]string{
"glob": globPattern,
"excludes": JoinWithPrefixAndQuote(excludes, "-e "),
func globToString(glob string) string {
ret := ""
for _, c := range glob {
if c >= 'a' && c <= 'z' ||
c >= 'A' && c <= 'Z' ||
c >= '0' && c <= '9' ||
c == '_' || c == '-' || c == '/' {
ret += string(c)
return ret