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- // Copyright (C) 2021 The Android Open Source Project
- //
- // Licensed under the Apache License, Version 2.0 (the "License");
- // you may not use this file except in compliance with the License.
- // You may obtain a copy of the License at
- //
- // http://www.apache.org/licenses/LICENSE-2.0
- //
- // Unless required by applicable law or agreed to in writing, software
- // distributed under the License is distributed on an "AS IS" BASIS,
- // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- // See the License for the specific language governing permissions and
- // limitations under the License.
- package sdk
- import (
- "reflect"
- "android/soong/android"
- "github.com/google/blueprint/proptools"
- )
- // Contains information about the sdk properties that list sdk members by trait, e.g.
- // native_bridge.
- type sdkMemberTraitListProperty struct {
- // getter for the list of member names
- getter func(properties interface{}) []string
- // the trait of member referenced in the list
- memberTrait android.SdkMemberTrait
- }
- // Cache of dynamically generated dynamicSdkMemberTraits objects. The key is the pointer
- // to a slice of SdkMemberTrait instances returned by android.RegisteredSdkMemberTraits().
- var dynamicSdkMemberTraitsMap android.OncePer
- // A dynamically generated set of member list properties and associated structure type.
- //
- // Instances of this are created by createDynamicSdkMemberTraits.
- type dynamicSdkMemberTraits struct {
- // The dynamically generated structure type.
- //
- // Contains one []string exported field for each SdkMemberTrait returned by android.RegisteredSdkMemberTraits(). The name of
- // the field is the exported form of the value returned by SdkMemberTrait.SdkPropertyName().
- propertiesStructType reflect.Type
- // Information about each of the member trait specific list properties.
- memberTraitListProperties []*sdkMemberTraitListProperty
- }
- func (d *dynamicSdkMemberTraits) createMemberTraitListProperties() interface{} {
- return reflect.New(d.propertiesStructType).Interface()
- }
- func getDynamicSdkMemberTraits(key android.OnceKey, registeredTraits []android.SdkMemberTrait) *dynamicSdkMemberTraits {
- // Get the cached value, creating new instance if necessary.
- return dynamicSdkMemberTraitsMap.Once(key, func() interface{} {
- return createDynamicSdkMemberTraits(registeredTraits)
- }).(*dynamicSdkMemberTraits)
- }
- // Create the dynamicSdkMemberTraits from the list of registered member traits.
- //
- // A struct is created which contains one exported field per member trait corresponding to
- // the SdkMemberTrait.SdkPropertyName() value.
- //
- // A list of sdkMemberTraitListProperty instances is created, one per member trait that provides:
- // * a reference to the member trait.
- // * a getter for the corresponding field in the properties struct.
- func createDynamicSdkMemberTraits(sdkMemberTraits []android.SdkMemberTrait) *dynamicSdkMemberTraits {
- var listProperties []*sdkMemberTraitListProperty
- memberTraitToProperty := map[android.SdkMemberTrait]*sdkMemberTraitListProperty{}
- var fields []reflect.StructField
- // Iterate over the member traits creating StructField and sdkMemberTraitListProperty objects.
- nextFieldIndex := 0
- for _, memberTrait := range sdkMemberTraits {
- p := memberTrait.SdkPropertyName()
- var getter func(properties interface{}) []string
- // Create a dynamic exported field for the member trait's property.
- fields = append(fields, reflect.StructField{
- Name: proptools.FieldNameForProperty(p),
- Type: reflect.TypeOf([]string{}),
- })
- // Copy the field index for use in the getter func as using the loop variable directly will
- // cause all funcs to use the last value.
- fieldIndex := nextFieldIndex
- nextFieldIndex += 1
- getter = func(properties interface{}) []string {
- // The properties is expected to be of the following form (where
- // <Module_traits> is the name of an SdkMemberTrait.SdkPropertyName().
- // properties *struct {<Module_traits> []string, ....}
- //
- // Although it accesses the field by index the following reflection code is equivalent to:
- // *properties.<Module_traits>
- //
- list := reflect.ValueOf(properties).Elem().Field(fieldIndex).Interface().([]string)
- return list
- }
- // Create an sdkMemberTraitListProperty for the member trait.
- memberListProperty := &sdkMemberTraitListProperty{
- getter: getter,
- memberTrait: memberTrait,
- }
- memberTraitToProperty[memberTrait] = memberListProperty
- listProperties = append(listProperties, memberListProperty)
- }
- // Create a dynamic struct from the collated fields.
- propertiesStructType := reflect.StructOf(fields)
- return &dynamicSdkMemberTraits{
- memberTraitListProperties: listProperties,
- propertiesStructType: propertiesStructType,
- }
- }
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