Add support to sdk/module_exports to specify required traits
Currently, every sdk member of a specific module type has to be treated
in the same way as every other sdk member of that type. e.g. it is not
possible for an sdk member to use different variants to other members
of the same type.
Adding a new member type for each different way to treat the members is
not scalable as if there were N different ways treat a member then it
would require 2^N types for all the possible combinations.
This adds a new traits mechanism that allows the behavior of member
types to be customized per sdk member. Each member type can specify a
list of supported traits and customize its behavior based on which
traits are required for each member. A trait can be supported by
multiple different member types.
Bug: 195754365
Test: m nothing
Change-Id: I165ac80d208c0402d2a9ffa8085bba29562c19b7
diff --git a/android/sdk.go b/android/sdk.go
index 100f63b..73a0308 100644
--- a/android/sdk.go
+++ b/android/sdk.go
@@ -15,6 +15,7 @@
package android
import (
+ "fmt"
"sort"
"strings"
@@ -376,6 +377,175 @@
var _ BpPrintable = BpPrintableBase{}
+// SdkMemberTrait represents a trait that members of an sdk module can contribute to the sdk
+// snapshot.
+//
+// A trait is simply a characteristic of sdk member that is not required by default which may be
+// required for some members but not others. Traits can cause additional information to be output
+// to the sdk snapshot or replace the default information exported for a member with something else.
+// e.g.
+// * By default cc libraries only export the default image variants to the SDK. However, for some
+// members it may be necessary to export specific image variants, e.g. vendor, or recovery.
+// * By default cc libraries export all the configured architecture variants except for the native
+// bridge architecture variants. However, for some members it may be necessary to export the
+// native bridge architecture variants as well.
+// * By default cc libraries export the platform variant (i.e. sdk:). However, for some members it
+// may be necessary to export the sdk variant (i.e. sdk:sdk).
+//
+// A sdk can request a module to provide no traits, one trait or a collection of traits. The exact
+// behavior of a trait is determined by how SdkMemberType implementations handle the traits. A trait
+// could be specific to one SdkMemberType or many. Some trait combinations could be incompatible.
+//
+// The sdk module type will create a special traits structure that contains a property for each
+// trait registered with RegisterSdkMemberTrait(). The property names are those returned from
+// SdkPropertyName(). Each property contains a list of modules that are required to have that trait.
+// e.g. something like this:
+//
+// sdk {
+// name: "sdk",
+// ...
+// traits: {
+// recovery_image: ["module1", "module4", "module5"],
+// native_bridge: ["module1", "module2"],
+// native_sdk: ["module1", "module3"],
+// ...
+// },
+// ...
+// }
+type SdkMemberTrait interface {
+ // SdkPropertyName returns the name of the traits property on an sdk module.
+ SdkPropertyName() string
+}
+
+// SdkMemberTraitBase is the base struct that must be embedded within any type that implements
+// SdkMemberTrait.
+type SdkMemberTraitBase struct {
+ // PropertyName is the name of the property
+ PropertyName string
+}
+
+func (b *SdkMemberTraitBase) SdkPropertyName() string {
+ return b.PropertyName
+}
+
+// SdkMemberTraitSet is a set of SdkMemberTrait instances.
+type SdkMemberTraitSet interface {
+ // Empty returns true if this set is empty.
+ Empty() bool
+
+ // Contains returns true if this set contains the specified trait.
+ Contains(trait SdkMemberTrait) bool
+
+ // Subtract returns a new set containing all elements of this set except for those in the
+ // other set.
+ Subtract(other SdkMemberTraitSet) SdkMemberTraitSet
+
+ // String returns a string representation of the set and its contents.
+ String() string
+}
+
+func NewSdkMemberTraitSet(traits []SdkMemberTrait) SdkMemberTraitSet {
+ if len(traits) == 0 {
+ return EmptySdkMemberTraitSet()
+ }
+
+ m := sdkMemberTraitSet{}
+ for _, trait := range traits {
+ m[trait] = true
+ }
+ return m
+}
+
+func EmptySdkMemberTraitSet() SdkMemberTraitSet {
+ return (sdkMemberTraitSet)(nil)
+}
+
+type sdkMemberTraitSet map[SdkMemberTrait]bool
+
+var _ SdkMemberTraitSet = (sdkMemberTraitSet{})
+
+func (s sdkMemberTraitSet) Empty() bool {
+ return len(s) == 0
+}
+
+func (s sdkMemberTraitSet) Contains(trait SdkMemberTrait) bool {
+ return s[trait]
+}
+
+func (s sdkMemberTraitSet) Subtract(other SdkMemberTraitSet) SdkMemberTraitSet {
+ if other.Empty() {
+ return s
+ }
+
+ var remainder []SdkMemberTrait
+ for trait, _ := range s {
+ if !other.Contains(trait) {
+ remainder = append(remainder, trait)
+ }
+ }
+
+ return NewSdkMemberTraitSet(remainder)
+}
+
+func (s sdkMemberTraitSet) String() string {
+ list := []string{}
+ for trait, _ := range s {
+ list = append(list, trait.SdkPropertyName())
+ }
+ sort.Strings(list)
+ return fmt.Sprintf("[%s]", strings.Join(list, ","))
+}
+
+// SdkMemberTraitsRegistry is a registry of SdkMemberTrait instances.
+type SdkMemberTraitsRegistry struct {
+ // The list of traits sorted by property name.
+ list []SdkMemberTrait
+}
+
+// copyAndAppend creates a new SdkMemberTraitsRegistry that includes all the traits registered in
+// this registry plus the supplied trait.
+func (r *SdkMemberTraitsRegistry) copyAndAppend(trait SdkMemberTrait) *SdkMemberTraitsRegistry {
+ oldList := r.list
+
+ // Copy the slice just in case this is being read while being modified, e.g. when testing.
+ list := make([]SdkMemberTrait, 0, len(oldList)+1)
+ list = append(list, oldList...)
+ list = append(list, trait)
+
+ // 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()
+ })
+
+ // Create a new registry so the pointer uniquely identifies the set of registered types.
+ return &SdkMemberTraitsRegistry{
+ list: list,
+ }
+}
+
+// RegisteredTraits returns the list of registered SdkMemberTrait instances.
+func (r *SdkMemberTraitsRegistry) RegisteredTraits() []SdkMemberTrait {
+ return r.list
+}
+
+// UniqueOnceKey returns a key to use with Config.Once that uniquely identifies this instance.
+func (r *SdkMemberTraitsRegistry) UniqueOnceKey() OnceKey {
+ // Use the pointer to the registry as the unique key.
+ return NewCustomOnceKey(r)
+}
+
+var RegisteredSdkMemberTraits = &SdkMemberTraitsRegistry{}
+
+// RegisterSdkMemberTrait registers an SdkMemberTrait object to allow them to be used in the
+// module_exports, module_exports_snapshot, sdk and sdk_snapshot module types.
+func RegisterSdkMemberTrait(trait SdkMemberTrait) {
+ RegisteredSdkMemberTraits = RegisteredSdkMemberTraits.copyAndAppend(trait)
+}
+
// SdkMember is an individual member of the SDK.
//
// It includes all of the variants that the SDK depends upon.
@@ -541,12 +711,23 @@
// CreateVariantPropertiesStruct creates a structure into which variant specific properties can be
// added.
CreateVariantPropertiesStruct() SdkMemberProperties
+
+ // SupportedTraits returns the set of traits supported by this member type.
+ SupportedTraits() SdkMemberTraitSet
}
// SdkDependencyContext provides access to information needed by the SdkMemberType.AddDependencies()
// implementations.
type SdkDependencyContext interface {
BottomUpMutatorContext
+
+ // RequiredTraits returns the set of SdkMemberTrait instances that the sdk requires the named
+ // member to provide.
+ RequiredTraits(name string) SdkMemberTraitSet
+
+ // RequiresTrait returns true if the sdk requires the member with the supplied name to provide the
+ // supplied trait.
+ RequiresTrait(name string, trait SdkMemberTrait) bool
}
// SdkMemberTypeBase is the base type for SdkMemberType implementations and must be embedded in any
@@ -565,6 +746,9 @@
// module type in its SdkMemberType.AddPrebuiltModule() method. That prevents the sdk snapshot
// code from automatically adding a prefer: true flag.
UseSourceModuleTypeInSnapshot bool
+
+ // The list of supported traits.
+ Traits []SdkMemberTrait
}
func (b *SdkMemberTypeBase) SdkPropertyName() string {
@@ -587,6 +771,10 @@
return b.UseSourceModuleTypeInSnapshot
}
+func (b *SdkMemberTypeBase) SupportedTraits() SdkMemberTraitSet {
+ return NewSdkMemberTraitSet(b.Traits)
+}
+
// SdkMemberTypesRegistry encapsulates the information about registered SdkMemberTypes.
type SdkMemberTypesRegistry struct {
// The list of types sorted by property name.
@@ -733,6 +921,9 @@
// Provided for use by sdk members to create a member specific location within the snapshot
// into which to copy the prebuilt files.
Name() string
+
+ // RequiresTrait returns true if this member is expected to provide the specified trait.
+ RequiresTrait(trait SdkMemberTrait) bool
}
// ExportedComponentsInfo contains information about the components that this module exports to an