soong_zip: add support for -j to junk paths

When -j is specified ignore the path to the source file and just
zip it with its filename.  -j overrides -C, and -C overrides -j,
so -j -f path1 -C dir -f path2 will junk the path for path1, but
treat path2 as relative to dir.

Remove the filepath.Clean for the FileArgs, it would convert ""
to "." sometimes, and everything gets cleaned in zip already for
the non-command-line use cases.

Test: m checkbuild
Change-Id: I7d90572c622ee0c6f35967ff31d067b5312c72eb

zip/zip.go

@@ -87,6 +87,7 @@ func (u *uniqueSet) Set(s string) error {
 type FileArg struct {
 	PathPrefixInZip, SourcePrefixToStrip string
 	SourceFiles                          []string
+	JunkPaths                            bool
 	GlobDir                              string
 }
 
@@ -228,8 +229,7 @@ func Run(args ZipArgs) (err error) {
 			srcs = append(srcs, recursiveGlobFiles(fa.GlobDir)...)
 		}
 		for _, src := range srcs {
-			err := fillPathPairs(fa.PathPrefixInZip, fa.SourcePrefixToStrip, src,
-				&pathMappings, args.NonDeflatedFiles, noCompression)
+			err := fillPathPairs(fa, src, &pathMappings, args.NonDeflatedFiles, noCompression)
 			if err != nil {
 				log.Fatal(err)
 			}
@@ -270,7 +270,7 @@ func Run(args ZipArgs) (err error) {
 	return nil
 }
 
-func fillPathPairs(prefix, rel, src string, pathMappings *[]pathMapping,
+func fillPathPairs(fa FileArg, src string, pathMappings *[]pathMapping,
 	nonDeflatedFiles map[string]bool, noCompression bool) error {
 
 	src = strings.TrimSpace(src)
@@ -278,11 +278,18 @@ func fillPathPairs(prefix, rel, src string, pathMappings *[]pathMapping,
 		return nil
 	}
 	src = filepath.Clean(src)
-	dest, err := filepath.Rel(rel, src)
-	if err != nil {
-		return err
+	var dest string
+
+	if fa.JunkPaths {
+		dest = filepath.Base(src)
+	} else {
+		var err error
+		dest, err = filepath.Rel(fa.SourcePrefixToStrip, src)
+		if err != nil {
+			return err
+		}
 	}
-	dest = filepath.Join(prefix, dest)
+	dest = filepath.Join(fa.PathPrefixInZip, dest)
 
 	zipMethod := zip.Deflate
 	if _, found := nonDeflatedFiles[dest]; found || noCompression {