Decouple addition of new sdk member types from sdk code
Previously, adding a new SdkMemberType would require adding a new
sdkMemberListProperty instance to the sdkMemberListProperties as well
as adding a new property into the sdkProperties struct. They are
potential sources of conflict and couple the sdk code with all the
packages that add members to it. This change switched to a
registration model that allows each package to register its sdk
member types decoupling them from the sdk code.
Adds an SdkPropertyName() method to SdkMemberType that specifies the
name of the property to use in the sdk/sdk_snapshot. Also provides
an SdkMemberTypeBase struct to be used by providers of SdkMemberType
implementations.
SdkMemberType instances are registered using the
RegisterSdkMemberType() func which sorts the registered instances
by their SdkPropertyName() to ensure the behavior is consistent and
not affected by order of registration.
When creating a new sdk module a dynamicSdkMemberTypes instance is
created that contains the following:
* A properties struct is created dynamically that contains a field for
each registered SdkMemberType, corresponding to that type's
SdkPropertyName().
* A list of sdkMemberListProperty instances is also created, one for
each registered SdkMemberType.
The dynamicSdkMemberTypes instance is cached using a key that uniquely
identifies the set of registered types just in case new types are
registered after one has been created, e.g. by tests.
Bug: 142918168
Test: m checkbuild
Change-Id: I4bf2bf56a2a49025aa41454048bc1e8ccc6baca2
diff --git a/android/sdk.go b/android/sdk.go
index 533bd0e..7956434 100644
--- a/android/sdk.go
+++ b/android/sdk.go
@@ -15,6 +15,7 @@
package android
import (
+ "sort"
"strings"
"github.com/google/blueprint"
@@ -218,18 +219,24 @@
// The basic implementation should look something like this, where ModuleType is
// the name of the module type being supported.
//
-// var ModuleTypeSdkMemberType = newModuleTypeSdkMemberType()
-//
-// func newModuleTypeSdkMemberType() android.SdkMemberType {
-// return &moduleTypeSdkMemberType{}
+// type moduleTypeSdkMemberType struct {
+// android.SdkMemberTypeBase
// }
//
-// type moduleTypeSdkMemberType struct {
+// func init() {
+// android.RegisterSdkMemberType(&moduleTypeSdkMemberType{
+// SdkMemberTypeBase: android.SdkMemberTypeBase{
+// PropertyName: "module_types",
+// },
+// }
// }
//
// ...methods...
//
type SdkMemberType interface {
+ // The name of the member type property on an sdk module.
+ SdkPropertyName() string
+
// Add dependencies from the SDK module to all the variants the member
// contributes to the SDK. The exact set of variants required is determined
// by the SDK and its properties. The dependencies must be added with the
@@ -254,3 +261,66 @@
// IsInstance(Module) method returned true.
BuildSnapshot(sdkModuleContext ModuleContext, builder SnapshotBuilder, member SdkMember)
}
+
+type SdkMemberTypeBase struct {
+ PropertyName string
+}
+
+func (b *SdkMemberTypeBase) SdkPropertyName() string {
+ return b.PropertyName
+}
+
+// Encapsulates the information about registered SdkMemberTypes.
+type SdkMemberTypesRegistry struct {
+ // The list of types sorted by property name.
+ list []SdkMemberType
+
+ // The key that uniquely identifies this registry instance.
+ key OnceKey
+}
+
+func (r *SdkMemberTypesRegistry) RegisteredTypes() []SdkMemberType {
+ return r.list
+}
+
+func (r *SdkMemberTypesRegistry) UniqueOnceKey() OnceKey {
+ // Use the pointer to the registry as the unique key.
+ return NewCustomOnceKey(r)
+}
+
+// The set of registered SdkMemberTypes.
+var SdkMemberTypes = &SdkMemberTypesRegistry{}
+
+// Register an SdkMemberType object to allow them to be used in the sdk and sdk_snapshot module
+// types.
+func RegisterSdkMemberType(memberType SdkMemberType) {
+ oldList := SdkMemberTypes.list
+
+ // Copy the slice just in case this is being read while being modified, e.g. when testing.
+ list := make([]SdkMemberType, 0, len(oldList)+1)
+ list = append(list, oldList...)
+ list = append(list, memberType)
+
+ // Sort the member types by their property name to ensure that registry order has no effect
+ // on behavior.
+ sort.Slice(list, func(i1, i2 int) bool {
+ t1 := list[i1]
+ t2 := list[i2]
+
+ return t1.SdkPropertyName() < t2.SdkPropertyName()
+ })
+
+ // Generate a key that identifies the slice of SdkMemberTypes by joining the property names
+ // from all the SdkMemberType .
+ var properties []string
+ for _, t := range list {
+ properties = append(properties, t.SdkPropertyName())
+ }
+ key := NewOnceKey(strings.Join(properties, "|"))
+
+ // Create a new registry so the pointer uniquely identifies the set of registered types.
+ SdkMemberTypes = &SdkMemberTypesRegistry{
+ list: list,
+ key: key,
+ }
+}