Refactor around apexKeysText singleton

apexkeys.txt should list the installed apexes. But for now it lists all
apexes in the source tree. To fix this, each apex(or prebuilt/apexset)
will generate its own apexkey info and they'll be merged into a single
text only for installed apexes.

This change is a preparation before the upcoming change. We'll reuse the
apexKeyEntry stuff from the current implementation.

Bug: 304914238
Test: m blueprint_tests
Change-Id: If9d5d992e5e2b0120e017265d2590b1c55152f52

apex/key.go

@@ -102,15 +102,7 @@ func (m *apexKey) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	}
 }
 
-// //////////////////////////////////////////////////////////////////////
+type apexKeyEntry struct {
-// apex_keys_text
-type apexKeysText struct {
-	output android.OutputPath
-}
-
-func (s *apexKeysText) GenerateBuildActions(ctx android.SingletonContext) {
-	s.output = android.PathForOutput(ctx, "apexkeys.txt")
-	type apexKeyEntry struct {
 	name                 string
 	presigned            bool
 	publicKey            string
@@ -119,8 +111,9 @@ func (s *apexKeysText) GenerateBuildActions(ctx android.SingletonContext) {
 	containerPrivateKey  string
 	partition            string
 	signTool             string
-	}
+}
-	toString := func(e apexKeyEntry) string {
+
+func (e apexKeyEntry) String() string {
 	signTool := ""
 	if e.signTool != "" {
 		signTool = fmt.Sprintf(" sign_tool=%q", e.signTool)
@@ -131,13 +124,13 @@ func (s *apexKeysText) GenerateBuildActions(ctx android.SingletonContext) {
 	} else {
 		return fmt.Sprintf(format, e.name, e.publicKey, e.privateKey, e.containerCertificate, e.containerPrivateKey, e.partition, signTool)
 	}
-	}
+}
 
-	apexKeyMap := make(map[string]apexKeyEntry)
+func apexKeyEntryFor(ctx android.SingletonContext, module android.Module) apexKeyEntry {
-	ctx.VisitAllModules(func(module android.Module) {
+	switch m := module.(type) {
-		if m, ok := module.(*apexBundle); ok && m.Enabled() && m.installable() {
+	case *apexBundle:
 		pem, key := m.getCertificateAndPrivateKey(ctx)
-			apexKeyMap[m.Name()] = apexKeyEntry{
+		return apexKeyEntry{
 			name:                 m.Name() + ".apex",
 			presigned:            false,
 			publicKey:            m.publicKeyFile.String(),
@@ -147,6 +140,35 @@ func (s *apexKeysText) GenerateBuildActions(ctx android.SingletonContext) {
 			partition:            m.PartitionTag(ctx.DeviceConfig()),
 			signTool:             proptools.String(m.properties.Custom_sign_tool),
 		}
+	case *Prebuilt:
+		return apexKeyEntry{
+			name:      m.InstallFilename(),
+			presigned: true,
+			partition: m.PartitionTag(ctx.DeviceConfig()),
+		}
+	case *ApexSet:
+		return apexKeyEntry{
+			name:      m.InstallFilename(),
+			presigned: true,
+			partition: m.PartitionTag(ctx.DeviceConfig()),
+		}
+	}
+	panic(fmt.Errorf("unknown type(%t) for apexKeyEntry", module))
+}
+
+// //////////////////////////////////////////////////////////////////////
+// apex_keys_text
+type apexKeysText struct {
+	output android.OutputPath
+}
+
+func (s *apexKeysText) GenerateBuildActions(ctx android.SingletonContext) {
+	s.output = android.PathForOutput(ctx, "apexkeys.txt")
+
+	apexKeyMap := make(map[string]apexKeyEntry)
+	ctx.VisitAllModules(func(module android.Module) {
+		if m, ok := module.(*apexBundle); ok && m.Enabled() && m.installable() {
+			apexKeyMap[m.Name()] = apexKeyEntryFor(ctx, m)
 		}
 	})
 
@@ -154,11 +176,7 @@ func (s *apexKeysText) GenerateBuildActions(ctx android.SingletonContext) {
 	ctx.VisitAllModules(func(module android.Module) {
 		if m, ok := module.(*Prebuilt); ok && m.Enabled() && m.installable() &&
 			m.Prebuilt().UsePrebuilt() {
-			apexKeyMap[m.BaseModuleName()] = apexKeyEntry{
+			apexKeyMap[m.BaseModuleName()] = apexKeyEntryFor(ctx, m)
-				name:      m.InstallFilename(),
-				presigned: true,
-				partition: m.PartitionTag(ctx.DeviceConfig()),
-			}
 		}
 	})
 
@@ -166,12 +184,7 @@ func (s *apexKeysText) GenerateBuildActions(ctx android.SingletonContext) {
 	// so that apex_set are not overridden by prebuilts.
 	ctx.VisitAllModules(func(module android.Module) {
 		if m, ok := module.(*ApexSet); ok && m.Enabled() {
-			entry := apexKeyEntry{
+			apexKeyMap[m.BaseModuleName()] = apexKeyEntryFor(ctx, m)
-				name:      m.InstallFilename(),
-				presigned: true,
-				partition: m.PartitionTag(ctx.DeviceConfig()),
-			}
-			apexKeyMap[m.BaseModuleName()] = entry
 		}
 	})
 
@@ -184,7 +197,7 @@ func (s *apexKeysText) GenerateBuildActions(ctx android.SingletonContext) {
 
 	var filecontent strings.Builder
 	for _, name := range moduleNames {
-		filecontent.WriteString(toString(apexKeyMap[name]))
+		filecontent.WriteString(apexKeyMap[name].String())
 	}
 	android.WriteFileRule(ctx, s.output, filecontent.String())
 }