Support handling build releases in sdk snapshot
Adds the following:
1. A buildRelease type to represent a single build release.
2. A buildReleaseSet type to represent a set of build releases.
3. Methods to create parse and use the previous new types.
4. Tests for the above.
Bug: 197842263
Test: m nothing
Change-Id: Ib0dd4fc32851a4fffde3fa02ea22c8369f8c2995
diff --git a/sdk/build_release.go b/sdk/build_release.go
new file mode 100644
index 0000000..f2379ae
--- /dev/null
+++ b/sdk/build_release.go
@@ -0,0 +1,160 @@
+// 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"
+ "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, T, etc.
+type buildRelease struct {
+ // The name of the release, e.g. S, T, etc.
+ name string
+
+ // The index of this structure within the buildReleases list.
+ ordinal int
+}
+
+// String returns the name of the build release.
+func (s *buildRelease) String() string {
+ return s.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(buildReleases[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{}
+ for _, release := range buildReleases {
+ if _, ok := s.contents[release]; ok {
+ list = append(list, release.name)
+ }
+ }
+ return fmt.Sprintf("[%s]", strings.Join(list, ","))
+}
+
+var (
+ // nameToBuildRelease contains a map from name to build release.
+ nameToBuildRelease = map[string]*buildRelease{}
+
+ // buildReleases lists all the available build releases.
+ buildReleases = []*buildRelease{}
+
+ // allBuildReleaseSet is the set of all build releases.
+ allBuildReleaseSet = &buildReleaseSet{contents: map[*buildRelease]struct{}{}}
+
+ // Add the build releases from oldest to newest.
+ buildReleaseS = initBuildRelease("S")
+ buildReleaseT = initBuildRelease("T")
+)
+
+// initBuildRelease creates a new build release with the specified name.
+func initBuildRelease(name string) *buildRelease {
+ ordinal := len(nameToBuildRelease)
+ release := &buildRelease{name: name, ordinal: ordinal}
+ nameToBuildRelease[name] = release
+ buildReleases = append(buildReleases, release)
+ allBuildReleaseSet.addItem(release)
+ return release
+}
+
+// latestBuildRelease returns the latest build release, i.e. the last one added.
+func latestBuildRelease() *buildRelease {
+ return buildReleases[len(buildReleases)-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 := latestBuildRelease()
+ set.addRange(start, end)
+ } 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
+}