move CollectDependencyAconfigFiles to android

This needs to be called by some modules in android.

Bug: 308625757
Test: manual
Change-Id: I389fcfd88a3f4bd85a9218fdd4dd66d8a239bb67

android/Android.bp

@@ -27,6 +27,7 @@ bootstrap_go_package {
         "androidmk-parser",
     ],
     srcs: [
+        "aconfig_providers.go",
         "androidmk.go",
         "apex.go",
         "apex_contributions.go",

android/aconfig_providers.go

@@ -0,0 +1,92 @@
+// Copyright 2023 Google Inc. All rights reserved.
+//
+// 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 android
+
+import (
+	"github.com/google/blueprint"
+)
+
+var (
+	mergeAconfigFilesRule = pctx.AndroidStaticRule("mergeAconfigFilesRule",
+		blueprint.RuleParams{
+			Command:     `${aconfig} dump --dedup --format protobuf --out $out $flags`,
+			CommandDeps: []string{"${aconfig}"},
+		}, "flags")
+	_ = pctx.HostBinToolVariable("aconfig", "aconfig")
+)
+
+// Provider published by aconfig_value_set
+type AconfigDeclarationsProviderData struct {
+	Package                     string
+	Container                   string
+	IntermediateCacheOutputPath WritablePath
+	IntermediateDumpOutputPath  WritablePath
+}
+
+var AconfigDeclarationsProviderKey = blueprint.NewProvider[AconfigDeclarationsProviderData]()
+
+// This is used to collect the aconfig declarations info on the transitive closure,
+// the data is keyed on the container.
+type AconfigTransitiveDeclarationsInfo struct {
+	AconfigFiles map[string]Paths
+}
+
+var AconfigTransitiveDeclarationsInfoProvider = blueprint.NewProvider[AconfigTransitiveDeclarationsInfo]()
+
+func CollectDependencyAconfigFiles(ctx ModuleContext, mergedAconfigFiles *map[string]Paths) {
+	if *mergedAconfigFiles == nil {
+		*mergedAconfigFiles = make(map[string]Paths)
+	}
+	ctx.VisitDirectDeps(func(module Module) {
+		if dep, _ := OtherModuleProvider(ctx, module, AconfigDeclarationsProviderKey); dep.IntermediateCacheOutputPath != nil {
+			(*mergedAconfigFiles)[dep.Container] = append((*mergedAconfigFiles)[dep.Container], dep.IntermediateCacheOutputPath)
+			return
+		}
+		if dep, _ := OtherModuleProvider(ctx, module, AconfigTransitiveDeclarationsInfoProvider); len(dep.AconfigFiles) > 0 {
+			for container, v := range dep.AconfigFiles {
+				(*mergedAconfigFiles)[container] = append((*mergedAconfigFiles)[container], v...)
+			}
+		}
+	})
+
+	for container, aconfigFiles := range *mergedAconfigFiles {
+		(*mergedAconfigFiles)[container] = mergeAconfigFiles(ctx, aconfigFiles)
+	}
+
+	SetProvider(ctx, AconfigTransitiveDeclarationsInfoProvider, AconfigTransitiveDeclarationsInfo{
+		AconfigFiles: *mergedAconfigFiles,
+	})
+}
+
+func mergeAconfigFiles(ctx ModuleContext, inputs Paths) Paths {
+	inputs = LastUniquePaths(inputs)
+	if len(inputs) == 1 {
+		return Paths{inputs[0]}
+	}
+
+	output := PathForModuleOut(ctx, "aconfig_merged.pb")
+
+	ctx.Build(pctx, BuildParams{
+		Rule:        mergeAconfigFilesRule,
+		Description: "merge aconfig files",
+		Inputs:      inputs,
+		Output:      output,
+		Args: map[string]string{
+			"flags": JoinWithPrefix(inputs.Strings(), "--cache "),
+		},
+	})
+
+	return Paths{output}
+}