Add DirectoryPath for nsjail genrule

This adds a new interface DirectoryPath representing directories
specified by dirgroup modules. As directories are not regular files,
DirectoryPath is meant to be incompatible with regular Path.

Bug: 375551969
Test: m nsjail_genrule_test
Change-Id: I55806121a3a222a8b02f1a080f25448d425447b3

5 files changed, 75 insertions, 31 deletions

diff --git a/android/dirgroup.go b/android/dirgroup.go
index 20c4d13a6..62fbaa5c8 100644
--- a/android/dirgroup.go
+++ b/android/dirgroup.go
@@ -39,8 +39,7 @@ type dirGroup struct {
 }
 
 type DirInfo struct {
-	// TODO(b/358302178): Use DirectoryPaths instead of Paths
-	Dirs Paths
+	Dirs DirectoryPaths
 }
 
 var DirProvider = blueprint.NewProvider[DirInfo]()
diff --git a/android/paths.go b/android/paths.go
index 371aed86d..339fb2bd9 100644
--- a/android/paths.go
+++ b/android/paths.go
@@ -550,15 +550,35 @@ func PathsRelativeToModuleSourceDir(input SourceInput) Paths {
 	return ret
 }
 
+type directoryPath struct {
+	basePath
+}
+
+func (d *directoryPath) String() string {
+	return d.basePath.String()
+}
+
+func (d *directoryPath) base() basePath {
+	return d.basePath
+}
+
+// DirectoryPath represents a source path for directories. Incompatible with Path by design.
+type DirectoryPath interface {
+	String() string
+	base() basePath
+}
+
+var _ DirectoryPath = (*directoryPath)(nil)
+
+type DirectoryPaths []DirectoryPath
+
 // DirectoryPathsForModuleSrcExcludes returns a Paths{} containing the resolved references in
 // directory paths. Elements of paths are resolved as:
 //   - filepath, relative to local module directory, resolves as a filepath relative to the local
 //     source directory
 //   - other modules using the ":name" syntax. These modules must implement DirProvider.
-//
-// TODO(b/358302178): Implement DirectoryPath and change the return type.
-func DirectoryPathsForModuleSrc(ctx ModuleMissingDepsPathContext, paths []string) Paths {
-	var ret Paths
+func DirectoryPathsForModuleSrc(ctx ModuleMissingDepsPathContext, paths []string) DirectoryPaths {
+	var ret DirectoryPaths
 
 	for _, path := range paths {
 		if m, t := SrcIsModuleWithTag(path); m != "" {
@@ -587,12 +607,12 @@ func DirectoryPathsForModuleSrc(ctx ModuleMissingDepsPathContext, paths []string
 			} else if !isDir {
 				ReportPathErrorf(ctx, "module directory path %q is not a directory", p)
 			} else {
-				ret = append(ret, p)
+				ret = append(ret, &directoryPath{basePath{path: p.path, rel: p.rel}})
 			}
 		}
 	}
 
-	seen := make(map[Path]bool, len(ret))
+	seen := make(map[DirectoryPath]bool, len(ret))
 	for _, path := range ret {
 		if seen[path] {
 			ReportPathErrorf(ctx, "duplicated path %q", path)
diff --git a/android/paths_test.go b/android/paths_test.go
index 941f0ca78..5e618f914 100644
--- a/android/paths_test.go
+++ b/android/paths_test.go
@@ -1592,6 +1592,12 @@ func TestPathRelativeToTop(t *testing.T) {
 	})
 }
 
+func TestDirectoryPathIsIncompatibleWithPath(t *testing.T) {
+	d := (DirectoryPath)(&directoryPath{})
+	_, ok := d.(Path)
+	AssertBoolEquals(t, "directoryPath shouldn't implement Path", ok, false)
+}
+
 func ExampleOutputPath_ReplaceExtension() {
 	ctx := &configErrorWrapper{
 		config: TestConfig("out", nil, "", nil),
diff --git a/android/rule_builder.go b/android/rule_builder.go
index 56de9cd00..403c18418 100644
--- a/android/rule_builder.go
+++ b/android/rule_builder.go
@@ -575,25 +575,28 @@ func (r *RuleBuilder) build(name string, desc string, ninjaEscapeCommandString b
 		nsjailCmd.WriteString(r.outDir.String())
 		nsjailCmd.WriteString(":nsjail_build_sandbox/out")
 
-		for _, input := range inputs {
+		addBindMount := func(src, dst string) {
 			nsjailCmd.WriteString(" -R $PWD/")
-			nsjailCmd.WriteString(input.String())
+			nsjailCmd.WriteString(src)
 			nsjailCmd.WriteString(":nsjail_build_sandbox/")
-			nsjailCmd.WriteString(r.nsjailPathForInputRel(input))
+			nsjailCmd.WriteString(dst)
+		}
+
+		for _, input := range inputs {
+			addBindMount(input.String(), r.nsjailPathForInputRel(input))
 		}
 		for _, tool := range tools {
-			nsjailCmd.WriteString(" -R $PWD/")
-			nsjailCmd.WriteString(tool.String())
-			nsjailCmd.WriteString(":nsjail_build_sandbox/")
-			nsjailCmd.WriteString(nsjailPathForToolRel(r.ctx, tool))
+			addBindMount(tool.String(), nsjailPathForToolRel(r.ctx, tool))
 		}
 		inputs = append(inputs, tools...)
 		for _, c := range r.commands {
+			for _, directory := range c.implicitDirectories {
+				addBindMount(directory.String(), directory.String())
+				// TODO(b/375551969): Add implicitDirectories to BuildParams, rather than relying on implicits
+				inputs = append(inputs, SourcePath{basePath: directory.base()})
+			}
 			for _, tool := range c.packagedTools {
-				nsjailCmd.WriteString(" -R $PWD/")
-				nsjailCmd.WriteString(tool.srcPath.String())
-				nsjailCmd.WriteString(":nsjail_build_sandbox/")
-				nsjailCmd.WriteString(nsjailPathForPackagedToolRel(tool))
+				addBindMount(tool.srcPath.String(), nsjailPathForPackagedToolRel(tool))
 				inputs = append(inputs, tool.srcPath)
 			}
 		}
@@ -917,16 +920,17 @@ func (r *RuleBuilder) build(name string, desc string, ninjaEscapeCommandString b
 type RuleBuilderCommand struct {
 	rule *RuleBuilder
 
-	buf           strings.Builder
-	inputs        Paths
-	implicits     Paths
-	orderOnlys    Paths
-	validations   Paths
-	outputs       WritablePaths
-	depFiles      WritablePaths
-	tools         Paths
-	packagedTools []PackagingSpec
-	rspFiles      []rspFileAndPaths
+	buf                 strings.Builder
+	inputs              Paths
+	implicits           Paths
+	orderOnlys          Paths
+	validations         Paths
+	outputs             WritablePaths
+	depFiles            WritablePaths
+	tools               Paths
+	packagedTools       []PackagingSpec
+	rspFiles            []rspFileAndPaths
+	implicitDirectories DirectoryPaths
 }
 
 type rspFileAndPaths struct {
@@ -951,6 +955,10 @@ func (c *RuleBuilderCommand) addImplicit(path Path) {
 	c.implicits = append(c.implicits, path)
 }
 
+func (c *RuleBuilderCommand) addImplicitDirectory(path DirectoryPath) {
+	c.implicitDirectories = append(c.implicitDirectories, path)
+}
+
 func (c *RuleBuilderCommand) addOrderOnly(path Path) {
 	checkPathNotNil(path)
 	c.orderOnlys = append(c.orderOnlys, path)
@@ -1313,6 +1321,16 @@ func (c *RuleBuilderCommand) Implicits(paths Paths) *RuleBuilderCommand {
 	return c
 }
 
+// ImplicitDirectory adds the specified input directory to the dependencies without modifying the
+// command line. Added directories will be bind-mounted for the nsjail.
+func (c *RuleBuilderCommand) ImplicitDirectory(path DirectoryPath) *RuleBuilderCommand {
+	if !c.rule.nsjail {
+		panic("ImplicitDirectory() must be called after Nsjail()")
+	}
+	c.addImplicitDirectory(path)
+	return c
+}
+
 // GetImplicits returns the command's implicit inputs.
 func (c *RuleBuilderCommand) GetImplicits() Paths {
 	return c.implicits
diff --git a/genrule/genrule.go b/genrule/genrule.go
index 1ab137837..1282bfbae 100644
--- a/genrule/genrule.go
+++ b/genrule/genrule.go
@@ -231,7 +231,7 @@ type generateTask struct {
 
 	// For nsjail tasks
 	useNsjail bool
-	dirSrcs   android.Paths
+	dirSrcs   android.DirectoryPaths
 }
 
 func (g *Module) GeneratedSourceFiles() android.Paths {
@@ -604,7 +604,8 @@ func (g *Module) generateCommonBuildActions(ctx android.ModuleContext) {
 
 		if task.useNsjail {
 			for _, input := range task.dirSrcs {
-				cmd.Implicit(input)
+				cmd.ImplicitDirectory(input)
+				// TODO(b/375551969): remove glob
 				if paths, err := ctx.GlobWithDeps(filepath.Join(input.String(), "**/*"), nil); err == nil {
 					rule.NsjailImplicits(android.PathsForSource(ctx, paths))
 				} else {