Add F2FS support for APEX build system

Add the new property payload_fs_type in apex module type. Either 'f2fs'
or 'ext4'. Default 'ext4'.

Test: m

Bug: 158453869
Change-Id: I36f373251bd597e11acb62af75437a87e2a531ec
Merged-In: I36f373251bd597e11acb62af75437a87e2a531ec
diff --git a/apex/apex.go b/apex/apex.go
index 1267ec7..03d25d8 100644
--- a/apex/apex.go
+++ b/apex/apex.go
@@ -41,6 +41,9 @@
 	imageApexType     = "image"
 	zipApexType       = "zip"
 	flattenedApexType = "flattened"
+
+	ext4FsType = "ext4"
+	f2fsFsType = "f2fs"
 )
 
 type dependencyTag struct {
@@ -1026,6 +1029,10 @@
 	// Should be only used in non-system apexes (e.g. vendor: true).
 	// Default is false.
 	Use_vndk_as_stable *bool
+
+	// The type of filesystem to use for an image apex. Either 'ext4' or 'f2fs'.
+	// Default 'ext4'.
+	Payload_fs_type *string
 }
 
 type apexTargetBundleProperties struct {
@@ -1233,6 +1240,24 @@
 	return false
 }
 
+type fsType int
+
+const (
+	ext4 fsType = iota
+	f2fs
+)
+
+func (f fsType) string() string {
+	switch f {
+	case ext4:
+		return ext4FsType
+	case f2fs:
+		return f2fsFsType
+	default:
+		panic(fmt.Errorf("unknown APEX payload type %d", f))
+	}
+}
+
 type apexBundle struct {
 	android.ModuleBase
 	android.DefaultableModuleBase
@@ -1298,6 +1323,8 @@
 
 	// Optional list of lint report zip files for apexes that contain java or app modules
 	lintReports android.Paths
+
+	payloadFsType fsType
 }
 
 func addDependenciesForNativeModules(ctx android.BottomUpMutatorContext,
@@ -2270,6 +2297,15 @@
 	a.installDir = android.PathForModuleInstall(ctx, "apex")
 	a.filesInfo = filesInfo
 
+	switch proptools.StringDefault(a.properties.Payload_fs_type, ext4FsType) {
+	case ext4FsType:
+		a.payloadFsType = ext4
+	case f2fsFsType:
+		a.payloadFsType = f2fs
+	default:
+		ctx.PropertyErrorf("payload_fs_type", "%q is not a valid filesystem for apex [ext4, f2fs]", *a.properties.Payload_fs_type)
+	}
+
 	// Optimization. If we are building bundled APEX, for the files that are gathered due to the
 	// transitive dependencies, don't place them inside the APEX, but place a symlink pointing
 	// the same library in the system partition, thus effectively sharing the same libraries