Add RuleBuilder.Installs().String()

Add a RuleBuilderInstalls type for a slice of RuleBuilderInstalls,
and give it a String() method that returns the list of installs
in the format that is convenient for passing to Make.

Test: rule_builder_test.go
Change-Id: I2e9cd9abf4dfb0ad312d0a6662f1567baf9cd222

2 files changed, 33 insertions, 3 deletions

diff --git a/android/rule_builder.go b/android/rule_builder.go
index 468b617b..3b869470 100644
--- a/android/rule_builder.go
+++ b/android/rule_builder.go
@@ -28,7 +28,7 @@ import (
 // graph.
 type RuleBuilder struct {
 	commands       []*RuleBuilderCommand
-	installs       []RuleBuilderInstall
+	installs       RuleBuilderInstalls
 	temporariesSet map[string]bool
 	restat         bool
 	missingDeps    []string
@@ -46,6 +46,23 @@ type RuleBuilderInstall struct {
 	From, To string
 }
 
+type RuleBuilderInstalls []RuleBuilderInstall
+
+// String returns the RuleBuilderInstalls in the form used by $(call copy-many-files) in Make, a space separated
+// list of from:to tuples.
+func (installs RuleBuilderInstalls) String() string {
+	sb := strings.Builder{}
+	for i, install := range installs {
+		if i != 0 {
+			sb.WriteRune(' ')
+		}
+		sb.WriteString(install.From)
+		sb.WriteRune(':')
+		sb.WriteString(install.To)
+	}
+	return sb.String()
+}
+
 // MissingDeps adds modules to the list of missing dependencies.  If MissingDeps
 // is called with a non-empty input, any call to Build will result in a rule
 // that will print an error listing the missing dependencies and fail.
@@ -145,8 +162,8 @@ func (r *RuleBuilder) Outputs() []string {
 }
 
 // Installs returns the list of tuples passed to Install.
-func (r *RuleBuilder) Installs() []RuleBuilderInstall {
-	return append([]RuleBuilderInstall(nil), r.installs...)
+func (r *RuleBuilder) Installs() RuleBuilderInstalls {
+	return append(RuleBuilderInstalls(nil), r.installs...)
 }
 
 func (r *RuleBuilder) toolsSet() map[string]bool {
diff --git a/android/rule_builder_test.go b/android/rule_builder_test.go
index 53a5b489..f9473489 100644
--- a/android/rule_builder_test.go
+++ b/android/rule_builder_test.go
@@ -84,6 +84,19 @@ func ExampleRuleBuilder_DeleteTemporaryFiles() {
 	// outputs: ["c"]
 }
 
+func ExampleRuleBuilder_Installs() {
+	rule := NewRuleBuilder()
+
+	rule.Command().Tool("ld").Inputs([]string{"a.o", "b.o"}).FlagWithOutput("-o ", "linked")
+	rule.Install("linked", "/bin/linked")
+	rule.Install("linked", "/sbin/linked")
+
+	fmt.Printf("rule.Installs().String() = %q\n", rule.Installs().String())
+
+	// Output:
+	// rule.Installs().String() = "linked:/bin/linked linked:/sbin/linked"
+}
+
 func ExampleRuleBuilderCommand() {
 	rule := NewRuleBuilder()