1 files changed, 209 insertions, 0 deletions
diff --git a/java/classpath_fragment.go b/java/classpath_fragment.go
new file mode 100644
index 000000000..ecfdfb7e5
--- /dev/null
+++ b/java/classpath_fragment.go
@@ -0,0 +1,209 @@
+/*
+ * 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 java
+
+import (
+	"fmt"
+	"github.com/google/blueprint"
+	"strings"
+
+	"android/soong/android"
+)
+
+// Build rules and utilities to generate individual packages/modules/SdkExtensions/proto/classpaths.proto
+// config files based on build configuration to embed into /system and /apex on a device.
+//
+// See `derive_classpath` service that reads the configs at runtime and defines *CLASSPATH variables
+// on the device.
+
+type classpathType int
+
+const (
+	// Matches definition in packages/modules/SdkExtensions/proto/classpaths.proto
+	BOOTCLASSPATH classpathType = iota
+	DEX2OATBOOTCLASSPATH
+	SYSTEMSERVERCLASSPATH
+)
+
+func (c classpathType) String() string {
+	return [...]string{"BOOTCLASSPATH", "DEX2OATBOOTCLASSPATH", "SYSTEMSERVERCLASSPATH"}[c]
+}
+
+type classpathFragmentProperties struct {
+}
+
+// classpathFragment interface is implemented by a module that contributes jars to a *CLASSPATH
+// variables at runtime.
+type classpathFragment interface {
+	android.Module
+
+	classpathFragmentBase() *ClasspathFragmentBase
+
+	// ClasspathFragmentToConfiguredJarList returns android.ConfiguredJarList representation of all
+	// the jars in this classpath fragment.
+	ClasspathFragmentToConfiguredJarList(ctx android.ModuleContext) android.ConfiguredJarList
+}
+
+// ClasspathFragmentBase is meant to be embedded in any module types that implement classpathFragment;
+// such modules are expected to call initClasspathFragment().
+type ClasspathFragmentBase struct {
+	properties classpathFragmentProperties
+
+	classpathType classpathType
+
+	outputFilepath android.OutputPath
+	installDirPath android.InstallPath
+}
+
+func (c *ClasspathFragmentBase) classpathFragmentBase() *ClasspathFragmentBase {
+	return c
+}
+
+// Initializes ClasspathFragmentBase struct. Must be called by all modules that include ClasspathFragmentBase.
+func initClasspathFragment(c classpathFragment, classpathType classpathType) {
+	base := c.classpathFragmentBase()
+	base.classpathType = classpathType
+	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
+}
+
+// gatherPossibleUpdatableModuleNamesAndStems returns a set of module and stem names from the
+// supplied contents that may be in the updatable boot jars.
+//
+// The module names are included because sometimes the stem is set to just change the name of
+// the installed file and it expects the configuration to still use the actual module name.
+//
+// The stem names are included because sometimes the stem is set to change the effective name of the
+// module that is used in the configuration as well,e .g. when a test library is overriding an
+// actual boot jar
+func gatherPossibleUpdatableModuleNamesAndStems(ctx android.ModuleContext, contents []string, tag blueprint.DependencyTag) []string {
+	set := map[string]struct{}{}
+	for _, name := range contents {
+		dep := ctx.GetDirectDepWithTag(name, tag)
+		set[name] = struct{}{}
+		if m, ok := dep.(ModuleWithStem); ok {
+			set[m.Stem()] = struct{}{}
+		} else {
+			ctx.PropertyErrorf("contents", "%v is not a ModuleWithStem", name)
+		}
+	}
+	return android.SortedStringKeys(set)
+}
+
+// Converts android.ConfiguredJarList into a list of classpathJars for each given classpathType.
+func configuredJarListToClasspathJars(ctx android.ModuleContext, configuredJars android.ConfiguredJarList, classpaths ...classpathType) []classpathJar {
+	paths := configuredJars.DevicePaths(ctx.Config(), android.Android)
+	jars := make([]classpathJar, 0, len(paths)*len(classpaths))
+	for i := 0; i < len(paths); i++ {
+		for _, classpathType := range classpaths {
+			jars = append(jars, classpathJar{
+				classpath: classpathType,
+				path:      paths[i],
+			})
+		}
+	}
+	return jars
+}
+
+func (c *ClasspathFragmentBase) generateClasspathProtoBuildActions(ctx android.ModuleContext, jars []classpathJar) {
+	outputFilename := strings.ToLower(c.classpathType.String()) + ".pb"
+	c.outputFilepath = android.PathForModuleOut(ctx, outputFilename).OutputPath
+	c.installDirPath = android.PathForModuleInstall(ctx, "etc", "classpaths")
+
+	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())
+
+	classpathProtoInfo := ClasspathFragmentProtoContentInfo{
+		ClasspathFragmentProtoInstallDir: c.installDirPath,
+		ClasspathFragmentProtoOutput:     c.outputFilepath,
+	}
+	ctx.SetProvider(ClasspathFragmentProtoContentInfoProvider, classpathProtoInfo)
+}
+
+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, "\"path\": \"%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())
+}
+
+// Returns AndroidMkEntries objects to install generated classpath.proto.
+// Do not use this to install into APEXes as the injection of the generated files happen separately for APEXes.
+func (c *ClasspathFragmentBase) androidMkEntries() []android.AndroidMkEntries {
+	return []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())
+			},
+		},
+	}}
+}
+
+var ClasspathFragmentProtoContentInfoProvider = blueprint.NewProvider(ClasspathFragmentProtoContentInfo{})
+
+type ClasspathFragmentProtoContentInfo struct {
+	// ClasspathFragmentProtoOutput is an output path for the generated classpaths.proto config of this module.
+	//
+	// The file should be copied to a relevant place on device, see ClasspathFragmentProtoInstallDir
+	// for more details.
+	ClasspathFragmentProtoOutput android.OutputPath
+
+	// ClasspathFragmentProtoInstallDir contains information about on device location for the generated classpaths.proto file.
+	//
+	// The path encodes expected sub-location within partitions, i.e. etc/classpaths/<proto-file>,
+	// for ClasspathFragmentProtoOutput. To get sub-location, instead of the full output / make path
+	// use android.InstallPath#Rel().
+	//
+	// This is only relevant for APEX modules as they perform their own installation; while regular
+	// system files are installed via ClasspathFragmentBase#androidMkEntries().
+	ClasspathFragmentProtoInstallDir android.InstallPath
+}