Move response file handling to a separate package

sbox is going to need to read and write response files, move ReadRspFile
to its own package.

Test: response_test.go
Change-Id: Iecb5486b4aaeb2531828743ad8ef784df675e18e
diff --git a/zip/Android.bp b/zip/Android.bp
index b28adbd..14541eb 100644
--- a/zip/Android.bp
+++ b/zip/Android.bp
@@ -25,6 +25,7 @@
         "android-archive-zip",
         "blueprint-pathtools",
         "soong-jar",
+        "soong-response",
     ],
     srcs: [
         "zip.go",
diff --git a/zip/cmd/main.go b/zip/cmd/main.go
index fc976f6..cbc73ed 100644
--- a/zip/cmd/main.go
+++ b/zip/cmd/main.go
@@ -24,7 +24,6 @@
 import (
 	"flag"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"runtime"
 	"runtime/pprof"
@@ -32,6 +31,7 @@
 	"strconv"
 	"strings"
 
+	"android/soong/response"
 	"android/soong/zip"
 )
 
@@ -125,12 +125,18 @@
 	var expandedArgs []string
 	for _, arg := range os.Args {
 		if strings.HasPrefix(arg, "@") {
-			bytes, err := ioutil.ReadFile(strings.TrimPrefix(arg, "@"))
+			f, err := os.Open(strings.TrimPrefix(arg, "@"))
 			if err != nil {
 				fmt.Fprintln(os.Stderr, err.Error())
 				os.Exit(1)
 			}
-			respArgs := zip.ReadRespFile(bytes)
+
+			respArgs, err := response.ReadRspFile(f)
+			f.Close()
+			if err != nil {
+				fmt.Fprintln(os.Stderr, err.Error())
+				os.Exit(1)
+			}
 			expandedArgs = append(expandedArgs, respArgs...)
 		} else {
 			expandedArgs = append(expandedArgs, arg)
diff --git a/zip/zip.go b/zip/zip.go
index 088ed0d..a6490d4 100644
--- a/zip/zip.go
+++ b/zip/zip.go
@@ -29,7 +29,8 @@
 	"sync"
 	"syscall"
 	"time"
-	"unicode"
+
+	"android/soong/response"
 
 	"github.com/google/blueprint/pathtools"
 
@@ -164,14 +165,12 @@
 	}
 	defer f.Close()
 
-	list, err := ioutil.ReadAll(f)
+	arg := b.state
+	arg.SourceFiles, err = response.ReadRspFile(f)
 	if err != nil {
 		b.err = err
 		return b
 	}
-
-	arg := b.state
-	arg.SourceFiles = ReadRespFile(list)
 	for i := range arg.SourceFiles {
 		arg.SourceFiles[i] = pathtools.MatchEscape(arg.SourceFiles[i])
 	}
@@ -253,49 +252,6 @@
 	Filesystem pathtools.FileSystem
 }
 
-const NOQUOTE = '\x00'
-
-func ReadRespFile(bytes []byte) []string {
-	var args []string
-	var arg []rune
-
-	isEscaping := false
-	quotingStart := NOQUOTE
-	for _, c := range string(bytes) {
-		switch {
-		case isEscaping:
-			if quotingStart == '"' {
-				if !(c == '"' || c == '\\') {
-					// '\"' or '\\' will be escaped under double quoting.
-					arg = append(arg, '\\')
-				}
-			}
-			arg = append(arg, c)
-			isEscaping = false
-		case c == '\\' && quotingStart != '\'':
-			isEscaping = true
-		case quotingStart == NOQUOTE && (c == '\'' || c == '"'):
-			quotingStart = c
-		case quotingStart != NOQUOTE && c == quotingStart:
-			quotingStart = NOQUOTE
-		case quotingStart == NOQUOTE && unicode.IsSpace(c):
-			// Current character is a space outside quotes
-			if len(arg) != 0 {
-				args = append(args, string(arg))
-			}
-			arg = arg[:0]
-		default:
-			arg = append(arg, c)
-		}
-	}
-
-	if len(arg) != 0 {
-		args = append(args, string(arg))
-	}
-
-	return args
-}
-
 func zipTo(args ZipArgs, w io.Writer) error {
 	if args.EmulateJar {
 		args.AddDirectoryEntriesToZip = true
diff --git a/zip/zip_test.go b/zip/zip_test.go
index b456ef8..a37ae41 100644
--- a/zip/zip_test.go
+++ b/zip/zip_test.go
@@ -535,78 +535,6 @@
 	}
 }
 
-func TestReadRespFile(t *testing.T) {
-	testCases := []struct {
-		name, in string
-		out      []string
-	}{
-		{
-			name: "single quoting test case 1",
-			in:   `./cmd '"'-C`,
-			out:  []string{"./cmd", `"-C`},
-		},
-		{
-			name: "single quoting test case 2",
-			in:   `./cmd '-C`,
-			out:  []string{"./cmd", `-C`},
-		},
-		{
-			name: "single quoting test case 3",
-			in:   `./cmd '\"'-C`,
-			out:  []string{"./cmd", `\"-C`},
-		},
-		{
-			name: "single quoting test case 4",
-			in:   `./cmd '\\'-C`,
-			out:  []string{"./cmd", `\\-C`},
-		},
-		{
-			name: "none quoting test case 1",
-			in:   `./cmd \'-C`,
-			out:  []string{"./cmd", `'-C`},
-		},
-		{
-			name: "none quoting test case 2",
-			in:   `./cmd \\-C`,
-			out:  []string{"./cmd", `\-C`},
-		},
-		{
-			name: "none quoting test case 3",
-			in:   `./cmd \"-C`,
-			out:  []string{"./cmd", `"-C`},
-		},
-		{
-			name: "double quoting test case 1",
-			in:   `./cmd "'"-C`,
-			out:  []string{"./cmd", `'-C`},
-		},
-		{
-			name: "double quoting test case 2",
-			in:   `./cmd "\\"-C`,
-			out:  []string{"./cmd", `\-C`},
-		},
-		{
-			name: "double quoting test case 3",
-			in:   `./cmd "\""-C`,
-			out:  []string{"./cmd", `"-C`},
-		},
-		{
-			name: "ninja rsp file",
-			in:   "'a'\nb\n'@'\n'foo'\\''bar'\n'foo\"bar'",
-			out:  []string{"a", "b", "@", "foo'bar", `foo"bar`},
-		},
-	}
-
-	for _, testCase := range testCases {
-		t.Run(testCase.name, func(t *testing.T) {
-			got := ReadRespFile([]byte(testCase.in))
-			if !reflect.DeepEqual(got, testCase.out) {
-				t.Errorf("expected %q got %q", testCase.out, got)
-			}
-		})
-	}
-}
-
 func TestSrcJar(t *testing.T) {
 	mockFs := pathtools.MockFs(map[string][]byte{
 		"wrong_package.java":       []byte("package foo;"),