Add rspfile support to RuleBuilder

Allow RuleBuilderCommands to use an rspfile with FlagWithRspFileInputList.
This requires being more careful with ninja escaping, as the rspfile
will be $out.rsp, and the value for $out may not be known yet so it
must be inserted as a ninja variable that must not be escaped.

Test: rule_builder_test.go
Change-Id: Ifa91e24a0bb8f0ceeb5c9bfa5689be2a4ff3b9cd

android/rule_builder.go

@@ -263,11 +263,36 @@ func (r *RuleBuilder) Tools() Paths {
 	return toolsList
 }
 
-// Commands returns a slice containing a the built command line for each call to RuleBuilder.Command.
+// RspFileInputs returns the list of paths that were passed to the RuleBuilderCommand.FlagWithRspFileInputList method.
+func (r *RuleBuilder) RspFileInputs() Paths {
+	var rspFileInputs Paths
+	for _, c := range r.commands {
+		if c.rspFileInputs != nil {
+			if rspFileInputs != nil {
+				panic("Multiple commands in a rule may not have rsp file inputs")
+			}
+			rspFileInputs = c.rspFileInputs
+		}
+	}
+
+	return rspFileInputs
+}
+
+// Commands returns a slice containing the built command line for each call to RuleBuilder.Command.
 func (r *RuleBuilder) Commands() []string {
 	var commands []string
 	for _, c := range r.commands {
-		commands = append(commands, c.buf.String())
+		commands = append(commands, c.String())
+	}
+	return commands
+}
+
+// NinjaEscapedCommands returns a slice containin the built command line after ninja escaping for each call to
+// RuleBuilder.Command.
+func (r *RuleBuilder) NinjaEscapedCommands() []string {
+	var commands []string
+	for _, c := range r.commands {
+		commands = append(commands, c.NinjaEscapedString())
 	}
 	return commands
 }
@@ -324,7 +349,7 @@ func (r *RuleBuilder) Build(pctx PackageContext, ctx BuilderContext, name string
 	}
 
 	tools := r.Tools()
-	commands := r.Commands()
+	commands := r.NinjaEscapedCommands()
 	outputs := r.Outputs()
 
 	if len(commands) == 0 {
@@ -334,7 +359,7 @@ func (r *RuleBuilder) Build(pctx PackageContext, ctx BuilderContext, name string
 		panic("No outputs specified from any Commands")
 	}
 
-	commandString := strings.Join(proptools.NinjaEscapeList(commands), " && ")
+	commandString := strings.Join(commands, " && ")
 
 	if r.sbox {
 		sboxOutputs := make([]string, len(outputs))
@@ -363,17 +388,27 @@ func (r *RuleBuilder) Build(pctx PackageContext, ctx BuilderContext, name string
 	}
 
 	// Ninja doesn't like multiple outputs when depfiles are enabled, move all but the first output to
-	// ImplicitOutputs.  RuleBuilder never uses "$out", so the distinction between Outputs and ImplicitOutputs
+	// ImplicitOutputs.  RuleBuilder only uses "$out" for the rsp file location, so the distinction between Outputs and
-	// doesn't matter.
+	// ImplicitOutputs doesn't matter.
 	output := outputs[0]
 	implicitOutputs := outputs[1:]
 
+	var rspFile, rspFileContent string
+	rspFileInputs := r.RspFileInputs()
+	if rspFileInputs != nil {
+		rspFile = "$out.rsp"
+		rspFileContent = "$in"
+	}
+
 	ctx.Build(pctx, BuildParams{
 		Rule: ctx.Rule(pctx, name, blueprint.RuleParams{
-			Command:     commandString,
+			Command:        commandString,
-			CommandDeps: tools.Strings(),
+			CommandDeps:    tools.Strings(),
-			Restat:      r.restat,
+			Restat:         r.restat,
+			Rspfile:        rspFile,
+			RspfileContent: rspFileContent,
 		}),
+		Inputs:          rspFileInputs,
 		Implicits:       r.Inputs(),
 		Output:          output,
 		ImplicitOutputs: implicitOutputs,
@@ -388,11 +423,15 @@ func (r *RuleBuilder) Build(pctx PackageContext, ctx BuilderContext, name string
 // RuleBuilderCommand, so they can be used chained or unchained.  All methods that add text implicitly add a single
 // space as a separator from the previous method.
 type RuleBuilderCommand struct {
-	buf      strings.Builder
+	buf           strings.Builder
-	inputs   Paths
+	inputs        Paths
-	outputs  WritablePaths
+	outputs       WritablePaths
-	depFiles WritablePaths
+	depFiles      WritablePaths
-	tools    Paths
+	tools         Paths
+	rspFileInputs Paths
+
+	// spans [start,end) of the command that should not be ninja escaped
+	unescapedSpans [][2]int
 
 	sbox       bool
 	sboxOutDir WritablePath
@@ -624,11 +663,56 @@ func (c *RuleBuilderCommand) FlagWithDepFile(flag string, path WritablePath) *Ru
 	return c.Text(flag + c.outputStr(path))
 }
 
+// FlagWithRspFileInputList adds the specified flag and path to an rspfile to the command line, with no separator
+// between them.  The paths will be written to the rspfile.
+func (c *RuleBuilderCommand) FlagWithRspFileInputList(flag string, paths Paths) *RuleBuilderCommand {
+	if c.rspFileInputs != nil {
+		panic("FlagWithRspFileInputList cannot be called if rsp file inputs have already been provided")
+	}
+
+	// Use an empty slice if paths is nil, the non-nil slice is used as an indicator that the rsp file must be
+	// generated.
+	if paths == nil {
+		paths = Paths{}
+	}
+
+	c.rspFileInputs = paths
+
+	rspFile := "$out.rsp"
+	c.FlagWithArg(flag, rspFile)
+	c.unescapedSpans = append(c.unescapedSpans, [2]int{c.buf.Len() - len(rspFile), c.buf.Len()})
+	return c
+}
+
 // String returns the command line.
 func (c *RuleBuilderCommand) String() string {
 	return c.buf.String()
 }
 
+// String returns the command line.
+func (c *RuleBuilderCommand) NinjaEscapedString() string {
+	return ninjaEscapeExceptForSpans(c.String(), c.unescapedSpans)
+}
+
+func ninjaEscapeExceptForSpans(s string, spans [][2]int) string {
+	if len(spans) == 0 {
+		return proptools.NinjaEscape(s)
+	}
+
+	sb := strings.Builder{}
+	sb.Grow(len(s) * 11 / 10)
+
+	i := 0
+	for _, span := range spans {
+		sb.WriteString(proptools.NinjaEscape(s[i:span[0]]))
+		sb.WriteString(s[span[0]:span[1]])
+		i = span[1]
+	}
+	sb.WriteString(proptools.NinjaEscape(s[i:]))
+
+	return sb.String()
+}
+
 func ninjaNameEscape(s string) string {
 	b := []byte(s)
 	escaped := false

android/rule_builder_test.go

@@ -38,6 +38,7 @@ func pathContext() PathContext {
 			"ls":      nil,
 			"turbine": nil,
 			"java":    nil,
+			"javac":   nil,
 		})
 }
 
@@ -235,6 +236,34 @@ func ExampleRuleBuilderCommand_FlagWithList() {
 	// ls --sort=time,size
 }
 
+func ExampleRuleBuilderCommand_FlagWithRspFileInputList() {
+	ctx := pathContext()
+	fmt.Println(NewRuleBuilder().Command().
+		Tool(PathForSource(ctx, "javac")).
+		FlagWithRspFileInputList("@", PathsForTesting("a.java", "b.java")).
+		NinjaEscapedString())
+	// Output:
+	// javac @$out.rsp
+}
+
+func ExampleRuleBuilderCommand_String() {
+	fmt.Println(NewRuleBuilder().Command().
+		Text("FOO=foo").
+		Text("echo $FOO").
+		String())
+	// Output:
+	// FOO=foo echo $FOO
+}
+
+func ExampleRuleBuilderCommand_NinjaEscapedString() {
+	fmt.Println(NewRuleBuilder().Command().
+		Text("FOO=foo").
+		Text("echo $FOO").
+		NinjaEscapedString())
+	// Output:
+	// FOO=foo echo $$FOO
+}
+
 func TestRuleBuilder(t *testing.T) {
 	fs := map[string][]byte{
 		"dep_fixer": nil,
@@ -503,3 +532,77 @@ func TestRuleBuilder_Build(t *testing.T) {
 			"cp bar "+outFile, outFile, outFile+".d", true, nil)
 	})
 }
+
+func Test_ninjaEscapeExceptForSpans(t *testing.T) {
+	type args struct {
+		s     string
+		spans [][2]int
+	}
+	tests := []struct {
+		name string
+		args args
+		want string
+	}{
+		{
+			name: "empty",
+			args: args{
+				s: "",
+			},
+			want: "",
+		},
+		{
+			name: "unescape none",
+			args: args{
+				s: "$abc",
+			},
+			want: "$$abc",
+		},
+		{
+			name: "unescape all",
+			args: args{
+				s:     "$abc",
+				spans: [][2]int{{0, 4}},
+			},
+			want: "$abc",
+		},
+		{
+			name: "unescape first",
+			args: args{
+				s:     "$abc$",
+				spans: [][2]int{{0, 1}},
+			},
+			want: "$abc$$",
+		},
+		{
+			name: "unescape last",
+			args: args{
+				s:     "$abc$",
+				spans: [][2]int{{4, 5}},
+			},
+			want: "$$abc$",
+		},
+		{
+			name: "unescape middle",
+			args: args{
+				s:     "$a$b$c$",
+				spans: [][2]int{{2, 5}},
+			},
+			want: "$$a$b$c$$",
+		},
+		{
+			name: "unescape multiple",
+			args: args{
+				s:     "$a$b$c$",
+				spans: [][2]int{{2, 3}, {4, 5}},
+			},
+			want: "$$a$b$c$$",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := ninjaEscapeExceptForSpans(tt.args.s, tt.args.spans); got != tt.want {
+				t.Errorf("ninjaEscapeExceptForSpans() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}