Generate classpaths.proto config for *CLASSPATH variables.

Instead of embedding "raw" values from PRODUCT_*_CLASSPATH variables
into /etc/classpath, encode them into classpaths.proto binary format.

Existing platform_bootclasspath{} module is used to generate the whole
monolithic config to begin with. Later, the config will be split
among individual bootclasspath_fragment and
systemserverclasspath_fragment modules.

Bug: 180105615
Test: m && launch_cvd
Change-Id: Ia66f521f8976ff78a62ecf91131d26db21064de7

java/classpath_fragment.go

@@ -17,6 +17,9 @@
 package java
 
 import (
+	"fmt"
+	"strings"
+
 	"android/soong/android"
 )
 
@@ -47,21 +50,102 @@ type classpathFragmentProperties struct {
 type classpathFragment interface {
 	android.Module
 
-	classpathFragmentBase() *classpathFragmentBase
+	classpathFragmentBase() *ClasspathFragmentBase
 }
 
-// classpathFragmentBase is meant to be embedded in any module types that implement classpathFragment;
+// ClasspathFragmentBase is meant to be embedded in any module types that implement classpathFragment;
 // such modules are expected to call initClasspathFragment().
-type classpathFragmentBase struct {
+type ClasspathFragmentBase struct {
 	properties classpathFragmentProperties
 
-	classpathType classpathType
-
 	outputFilepath android.OutputPath
+	installDirPath android.InstallPath
 }
 
-// Initializes classpathFragmentBase struct. Must be called by all modules that include classpathFragmentBase.
+func (c *ClasspathFragmentBase) classpathFragmentBase() *ClasspathFragmentBase {
+	return c
+}
+
+// Initializes ClasspathFragmentBase struct. Must be called by all modules that include ClasspathFragmentBase.
 func initClasspathFragment(c classpathFragment) {
 	base := c.classpathFragmentBase()
 	c.AddProperties(&base.properties)
 }
+
+// Matches definition of Jar in packages/modules/SdkExtensions/proto/classpaths.proto
+type classpathJar struct {
+	path      string
+	classpath classpathType
+	// TODO(satayev): propagate min/max sdk versions for the jars
+	minSdkVersion int32
+	maxSdkVersion int32
+}
+
+func (c *ClasspathFragmentBase) generateAndroidBuildActions(ctx android.ModuleContext) {
+	outputFilename := ctx.ModuleName() + ".pb"
+	c.outputFilepath = android.PathForModuleOut(ctx, outputFilename).OutputPath
+	c.installDirPath = android.PathForModuleInstall(ctx, "etc", "classpaths")
+
+	var jars []classpathJar
+	jars = appendClasspathJar(jars, BOOTCLASSPATH, defaultBootclasspath(ctx)...)
+	jars = appendClasspathJar(jars, DEX2OATBOOTCLASSPATH, defaultBootImageConfig(ctx).getAnyAndroidVariant().dexLocationsDeps...)
+	jars = appendClasspathJar(jars, SYSTEMSERVERCLASSPATH, systemServerClasspath(ctx)...)
+
+	generatedJson := android.PathForModuleOut(ctx, outputFilename+".json")
+	writeClasspathsJson(ctx, generatedJson, jars)
+
+	rule := android.NewRuleBuilder(pctx, ctx)
+	rule.Command().
+		BuiltTool("conv_classpaths_proto").
+		Flag("encode").
+		Flag("--format=json").
+		FlagWithInput("--input=", generatedJson).
+		FlagWithOutput("--output=", c.outputFilepath)
+
+	rule.Build("classpath_fragment", "Compiling "+c.outputFilepath.String())
+}
+
+func writeClasspathsJson(ctx android.ModuleContext, output android.WritablePath, jars []classpathJar) {
+	var content strings.Builder
+	fmt.Fprintf(&content, "{\n")
+	fmt.Fprintf(&content, "\"jars\": [\n")
+	for idx, jar := range jars {
+		fmt.Fprintf(&content, "{\n")
+
+		fmt.Fprintf(&content, "\"relativePath\": \"%s\",\n", jar.path)
+		fmt.Fprintf(&content, "\"classpath\": \"%s\"\n", jar.classpath)
+
+		if idx < len(jars)-1 {
+			fmt.Fprintf(&content, "},\n")
+		} else {
+			fmt.Fprintf(&content, "}\n")
+		}
+	}
+	fmt.Fprintf(&content, "]\n")
+	fmt.Fprintf(&content, "}\n")
+	android.WriteFileRule(ctx, output, content.String())
+}
+
+func appendClasspathJar(slice []classpathJar, classpathType classpathType, paths ...string) (result []classpathJar) {
+	result = append(result, slice...)
+	for _, path := range paths {
+		result = append(result, classpathJar{
+			path:      path,
+			classpath: classpathType,
+		})
+	}
+	return
+}
+
+func (c *ClasspathFragmentBase) getAndroidMkEntries() []android.AndroidMkEntries {
+	return []android.AndroidMkEntries{android.AndroidMkEntries{
+		Class:      "ETC",
+		OutputFile: android.OptionalPathForPath(c.outputFilepath),
+		ExtraEntries: []android.AndroidMkExtraEntriesFunc{
+			func(ctx android.AndroidMkExtraEntriesContext, entries *android.AndroidMkEntries) {
+				entries.SetString("LOCAL_MODULE_PATH", c.installDirPath.ToMakePath().String())
+				entries.SetString("LOCAL_INSTALLED_MODULE_STEM", c.outputFilepath.Base())
+			},
+		},
+	}}
+}