From ed885bb7dd15d8c3b099ba504ce050f6508f62c1 Mon Sep 17 00:00:00 2001
From: Gurpreet Singh <gurpreetgs@google.com>
Date: Fri, 21 Apr 2023 16:30:03 +0000
Subject: [PATCH] Add genrule to build *.latest.version build target.

Build a new target *.latest.version which will contain a text file
containing the last finalized version.

Bug: 242316893, 282140551
Test: atest prebuilt_apis_test
(cherry picked from https://android-review.googlesource.com/q/commit:daa314ac97d5ab8076113ee7f269b4e4cc3cf620)
Merged-In: I41fa91c9ec273f342b7807c66c4d65ba13260124
Change-Id: I41fa91c9ec273f342b7807c66c4d65ba13260124
---
 java/prebuilt_apis.go | 28 ++++++++++++++++++++++++----
 1 file changed, 24 insertions(+), 4 deletions(-)

diff --git a/java/prebuilt_apis.go b/java/prebuilt_apis.go
index 206d99527..0740467eb 100644
--- a/java/prebuilt_apis.go
+++ b/java/prebuilt_apis.go
@@ -135,6 +135,19 @@ func createApiModule(mctx android.LoadHookContext, name string, path string) {
 	mctx.CreateModule(genrule.GenRuleFactory, &genruleProps)
 }
 
+func createLatestApiModuleExtensionVersionFile(mctx android.LoadHookContext, name string, version string) {
+	genruleProps := struct {
+		Name *string
+		Srcs []string
+		Out  []string
+		Cmd  *string
+	}{}
+	genruleProps.Name = proptools.StringPtr(name)
+	genruleProps.Out = []string{name}
+	genruleProps.Cmd = proptools.StringPtr("echo " + version + " > $(out)")
+	mctx.CreateModule(genrule.GenRuleFactory, &genruleProps)
+}
+
 func createEmptyFile(mctx android.LoadHookContext, name string) {
 	props := struct {
 		Name *string
@@ -233,9 +246,10 @@ func prebuiltApiFiles(mctx android.LoadHookContext, p *prebuiltApis) {
 	type latestApiInfo struct {
 		module, scope, path string
 		version             int
+		isExtensionApiFile  bool
 	}
 
-	getLatest := func(files []string) map[string]latestApiInfo {
+	getLatest := func(files []string, isExtensionApiFile bool) map[string]latestApiInfo {
 		m := make(map[string]latestApiInfo)
 		for _, f := range files {
 			module, version, scope := parseFinalizedPrebuiltPath(mctx, f)
@@ -245,16 +259,16 @@ func prebuiltApiFiles(mctx android.LoadHookContext, p *prebuiltApis) {
 			key := module + "." + scope
 			info, exists := m[key]
 			if !exists || version > info.version {
-				m[key] = latestApiInfo{module, scope, f, version}
+				m[key] = latestApiInfo{module, scope, f, version, isExtensionApiFile}
 			}
 		}
 		return m
 	}
 
-	latest := getLatest(apiLevelFiles)
+	latest := getLatest(apiLevelFiles, false)
 	if p.properties.Extensions_dir != nil {
 		extensionApiFiles := globExtensionDirs(mctx, p, "api/*.txt")
-		for k, v := range getLatest(extensionApiFiles) {
+		for k, v := range getLatest(extensionApiFiles, true) {
 			if _, exists := latest[k]; !exists {
 				mctx.ModuleErrorf("Module %v finalized for extension %d but never during an API level; likely error", v.module, v.version)
 			}
@@ -267,6 +281,12 @@ func prebuiltApiFiles(mctx android.LoadHookContext, p *prebuiltApis) {
 	for _, k := range android.SortedKeys(latest) {
 		info := latest[k]
 		name := PrebuiltApiModuleName(info.module, info.scope, "latest")
+		latestExtensionVersionModuleName := PrebuiltApiModuleName(info.module, info.scope, "latest.extension_version")
+		if info.isExtensionApiFile {
+			createLatestApiModuleExtensionVersionFile(mctx, latestExtensionVersionModuleName, strconv.Itoa(info.version))
+		} else {
+			createLatestApiModuleExtensionVersionFile(mctx, latestExtensionVersionModuleName, "-1")
+		}
 		createApiModule(mctx, name, info.path)
 	}