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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 (
- "fmt"
- "math"
- "reflect"
- "strings"
- )
- // Supports customizing sdk snapshot output based on target build release.
- // buildRelease represents the version of a build system used to create a specific release.
- //
- // The name of the release, is the same as the code for the dessert release, e.g. S, Tiramisu, etc.
- type buildRelease struct {
- // The name of the release, e.g. S, Tiramisu, etc.
- name string
- // The index of this structure within the dessertBuildReleases list.
- //
- // The buildReleaseCurrent does not appear in the dessertBuildReleases list as it has an ordinal value
- // that is larger than the size of the dessertBuildReleases.
- ordinal int
- }
- func (br *buildRelease) EarlierThan(other *buildRelease) bool {
- return br.ordinal < other.ordinal
- }
- // String returns the name of the build release.
- func (br *buildRelease) String() string {
- return br.name
- }
- // buildReleaseSet represents a set of buildRelease objects.
- type buildReleaseSet struct {
- // Set of *buildRelease represented as a map from *buildRelease to struct{}.
- contents map[*buildRelease]struct{}
- }
- // addItem adds a build release to the set.
- func (s *buildReleaseSet) addItem(release *buildRelease) {
- s.contents[release] = struct{}{}
- }
- // addRange adds all the build releases from start (inclusive) to end (inclusive).
- func (s *buildReleaseSet) addRange(start *buildRelease, end *buildRelease) {
- for i := start.ordinal; i <= end.ordinal; i += 1 {
- s.addItem(dessertBuildReleases[i])
- }
- }
- // contains returns true if the set contains the specified build release.
- func (s *buildReleaseSet) contains(release *buildRelease) bool {
- _, ok := s.contents[release]
- return ok
- }
- // String returns a string representation of the set, sorted from earliest to latest release.
- func (s *buildReleaseSet) String() string {
- list := []string{}
- addRelease := func(release *buildRelease) {
- if _, ok := s.contents[release]; ok {
- list = append(list, release.name)
- }
- }
- // Add the names of the build releases in this set in the order in which they were created.
- for _, release := range dessertBuildReleases {
- addRelease(release)
- }
- // Always add "current" to the list of names last if it is present in the set.
- addRelease(buildReleaseCurrent)
- return fmt.Sprintf("[%s]", strings.Join(list, ","))
- }
- var (
- // nameToBuildRelease contains a map from name to build release.
- nameToBuildRelease = map[string]*buildRelease{}
- // dessertBuildReleases lists all the available dessert build releases, i.e. excluding current.
- dessertBuildReleases = []*buildRelease{}
- // allBuildReleaseSet is the set of all build releases.
- allBuildReleaseSet = &buildReleaseSet{contents: map[*buildRelease]struct{}{}}
- // Add the dessert build releases from oldest to newest.
- buildReleaseS = initBuildRelease("S")
- buildReleaseT = initBuildRelease("Tiramisu")
- buildReleaseU = initBuildRelease("UpsideDownCake")
- // Add the current build release which is always treated as being more recent than any other
- // build release, including those added in tests.
- buildReleaseCurrent = initBuildRelease("current")
- )
- // initBuildRelease creates a new build release with the specified name.
- func initBuildRelease(name string) *buildRelease {
- ordinal := len(dessertBuildReleases)
- if name == "current" {
- // The current build release is more recent than all other build releases, including those
- // created in tests so use the max int value. It cannot just rely on being created after all
- // the other build releases as some are created in tests which run after the current build
- // release has been created.
- ordinal = math.MaxInt
- }
- release := &buildRelease{name: name, ordinal: ordinal}
- nameToBuildRelease[name] = release
- allBuildReleaseSet.addItem(release)
- if name != "current" {
- // As the current build release has an ordinal value that does not correspond to its position
- // in the dessertBuildReleases list do not add it to the list.
- dessertBuildReleases = append(dessertBuildReleases, release)
- }
- return release
- }
- // latestDessertBuildRelease returns the latest dessert release build name, i.e. the last dessert
- // release added to the list, which does not include current.
- func latestDessertBuildRelease() *buildRelease {
- return dessertBuildReleases[len(dessertBuildReleases)-1]
- }
- // nameToRelease maps from build release name to the corresponding build release (if it exists) or
- // the error if it does not.
- func nameToRelease(name string) (*buildRelease, error) {
- if r, ok := nameToBuildRelease[name]; ok {
- return r, nil
- }
- return nil, fmt.Errorf("unknown release %q, expected one of %s", name, allBuildReleaseSet)
- }
- // parseBuildReleaseSet parses a build release set string specification into a build release set.
- //
- // The specification consists of one of the following:
- // * a single build release name, e.g. S, T, etc.
- // * a closed range (inclusive to inclusive), e.g. S-T
- // * an open range, e.g. T+.
- //
- // This returns the set if the specification was valid or an error.
- func parseBuildReleaseSet(specification string) (*buildReleaseSet, error) {
- set := &buildReleaseSet{contents: map[*buildRelease]struct{}{}}
- if strings.HasSuffix(specification, "+") {
- rangeStart := strings.TrimSuffix(specification, "+")
- start, err := nameToRelease(rangeStart)
- if err != nil {
- return nil, err
- }
- end := latestDessertBuildRelease()
- set.addRange(start, end)
- // An open-ended range always includes the current release.
- set.addItem(buildReleaseCurrent)
- } else if strings.Contains(specification, "-") {
- limits := strings.SplitN(specification, "-", 2)
- start, err := nameToRelease(limits[0])
- if err != nil {
- return nil, err
- }
- end, err := nameToRelease(limits[1])
- if err != nil {
- return nil, err
- }
- if start.ordinal > end.ordinal {
- return nil, fmt.Errorf("invalid closed range, start release %q is later than end release %q", start.name, end.name)
- }
- set.addRange(start, end)
- } else {
- release, err := nameToRelease(specification)
- if err != nil {
- return nil, err
- }
- set.addItem(release)
- }
- return set, nil
- }
- // Given a set of properties (struct value), set the value of a field within that struct (or one of
- // its embedded structs) to its zero value.
- type fieldPrunerFunc func(structValue reflect.Value)
- // A property that can be cleared by a propertyPruner.
- type prunerProperty struct {
- // The name of the field for this property. It is a "."-separated path for fields in non-anonymous
- // sub-structs.
- name string
- // Sets the associated field to its zero value.
- prunerFunc fieldPrunerFunc
- }
- // propertyPruner provides support for pruning (i.e. setting to their zero value) properties from
- // a properties structure.
- type propertyPruner struct {
- // The properties that the pruner will clear.
- properties []prunerProperty
- }
- // gatherFields recursively processes the supplied structure and a nested structures, selecting the
- // fields that require pruning and populates the propertyPruner.properties with the information
- // needed to prune those fields.
- //
- // containingStructAccessor is a func that if given an object will return a field whose value is
- // of the supplied structType. It is nil on initial entry to this method but when this method is
- // called recursively on a field that is a nested structure containingStructAccessor is set to a
- // func that provides access to the field's value.
- //
- // namePrefix is the prefix to the fields that are being visited. It is "" on initial entry to this
- // method but when this method is called recursively on a field that is a nested structure
- // namePrefix is the result of appending the field name (plus a ".") to the previous name prefix.
- // Unless the field is anonymous in which case it is passed through unchanged.
- //
- // selector is a func that will select whether the supplied field requires pruning or not. If it
- // returns true then the field will be added to those to be pruned, otherwise it will not.
- func (p *propertyPruner) gatherFields(structType reflect.Type, containingStructAccessor fieldAccessorFunc, namePrefix string, selector fieldSelectorFunc) {
- for f := 0; f < structType.NumField(); f++ {
- field := structType.Field(f)
- if field.PkgPath != "" {
- // Ignore unexported fields.
- continue
- }
- // Save a copy of the field index for use in the function.
- fieldIndex := f
- name := namePrefix + field.Name
- fieldGetter := func(container reflect.Value) reflect.Value {
- if containingStructAccessor != nil {
- // This is an embedded structure so first access the field for the embedded
- // structure.
- container = containingStructAccessor(container)
- }
- // Skip through interface and pointer values to find the structure.
- container = getStructValue(container)
- defer func() {
- if r := recover(); r != nil {
- panic(fmt.Errorf("%s for fieldIndex %d of field %s of container %#v", r, fieldIndex, name, container.Interface()))
- }
- }()
- // Return the field.
- return container.Field(fieldIndex)
- }
- fieldType := field.Type
- if selector(name, field) {
- zeroValue := reflect.Zero(fieldType)
- fieldPruner := func(container reflect.Value) {
- if containingStructAccessor != nil {
- // This is an embedded structure so first access the field for the embedded
- // structure.
- container = containingStructAccessor(container)
- }
- // Skip through interface and pointer values to find the structure.
- container = getStructValue(container)
- defer func() {
- if r := recover(); r != nil {
- panic(fmt.Errorf("%s\n\tfor field (index %d, name %s)", r, fieldIndex, name))
- }
- }()
- // Set the field.
- container.Field(fieldIndex).Set(zeroValue)
- }
- property := prunerProperty{
- name,
- fieldPruner,
- }
- p.properties = append(p.properties, property)
- } else {
- switch fieldType.Kind() {
- case reflect.Struct:
- // Gather fields from the nested or embedded structure.
- var subNamePrefix string
- if field.Anonymous {
- subNamePrefix = namePrefix
- } else {
- subNamePrefix = name + "."
- }
- p.gatherFields(fieldType, fieldGetter, subNamePrefix, selector)
- case reflect.Map:
- // Get the type of the values stored in the map.
- valueType := fieldType.Elem()
- // Skip over * types.
- if valueType.Kind() == reflect.Ptr {
- valueType = valueType.Elem()
- }
- if valueType.Kind() == reflect.Struct {
- // If this is not referenced by a pointer then it is an error as it is impossible to
- // modify a struct that is stored directly as a value in a map.
- if fieldType.Elem().Kind() != reflect.Ptr {
- panic(fmt.Errorf("Cannot prune struct %s stored by value in map %s, map values must"+
- " be pointers to structs",
- fieldType.Elem(), name))
- }
- // Create a new pruner for the values of the map.
- valuePruner := newPropertyPrunerForStructType(valueType, selector)
- // Create a new fieldPruner that will iterate over all the items in the map and call the
- // pruner on them.
- fieldPruner := func(container reflect.Value) {
- mapValue := fieldGetter(container)
- for _, keyValue := range mapValue.MapKeys() {
- itemValue := mapValue.MapIndex(keyValue)
- defer func() {
- if r := recover(); r != nil {
- panic(fmt.Errorf("%s\n\tfor key %q", r, keyValue))
- }
- }()
- valuePruner.pruneProperties(itemValue.Interface())
- }
- }
- // Add the map field pruner to the list of property pruners.
- property := prunerProperty{
- name + "[*]",
- fieldPruner,
- }
- p.properties = append(p.properties, property)
- }
- }
- }
- }
- }
- // pruneProperties will prune (set to zero value) any properties in the struct referenced by the
- // supplied struct pointer.
- //
- // The struct must be of the same type as was originally passed to newPropertyPruner to create this
- // propertyPruner.
- func (p *propertyPruner) pruneProperties(propertiesStruct interface{}) {
- defer func() {
- if r := recover(); r != nil {
- panic(fmt.Errorf("%s\n\tof container %#v", r, propertiesStruct))
- }
- }()
- structValue := reflect.ValueOf(propertiesStruct)
- for _, property := range p.properties {
- property.prunerFunc(structValue)
- }
- }
- // fieldSelectorFunc is called to select whether a specific field should be pruned or not.
- // name is the name of the field, including any prefixes from containing str
- type fieldSelectorFunc func(name string, field reflect.StructField) bool
- // newPropertyPruner creates a new property pruner for the structure type for the supplied
- // properties struct.
- //
- // The returned pruner can be used on any properties structure of the same type as the supplied set
- // of properties.
- func newPropertyPruner(propertiesStruct interface{}, selector fieldSelectorFunc) *propertyPruner {
- structType := getStructValue(reflect.ValueOf(propertiesStruct)).Type()
- return newPropertyPrunerForStructType(structType, selector)
- }
- // newPropertyPruner creates a new property pruner for the supplied properties struct type.
- //
- // The returned pruner can be used on any properties structure of the supplied type.
- func newPropertyPrunerForStructType(structType reflect.Type, selector fieldSelectorFunc) *propertyPruner {
- pruner := &propertyPruner{}
- pruner.gatherFields(structType, nil, "", selector)
- return pruner
- }
- // newPropertyPrunerByBuildRelease creates a property pruner that will clear any properties in the
- // structure which are not supported by the specified target build release.
- //
- // A property is pruned if its field has a tag of the form:
- //
- // `supported_build_releases:"<build-release-set>"`
- //
- // and the resulting build release set does not contain the target build release. Properties that
- // have no such tag are assumed to be supported by all releases.
- func newPropertyPrunerByBuildRelease(propertiesStruct interface{}, targetBuildRelease *buildRelease) *propertyPruner {
- return newPropertyPruner(propertiesStruct, func(name string, field reflect.StructField) bool {
- if supportedBuildReleases, ok := field.Tag.Lookup("supported_build_releases"); ok {
- set, err := parseBuildReleaseSet(supportedBuildReleases)
- if err != nil {
- panic(fmt.Errorf("invalid `supported_build_releases` tag on %s of %T: %s", name, propertiesStruct, err))
- }
- // If the field does not support tha target release then prune it.
- return !set.contains(targetBuildRelease)
- } else {
- // Any untagged fields are assumed to be supported by all build releases so should never be
- // pruned.
- return false
- }
- })
- }
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