Separate mutators and modules creation into a separate file in fsgen

filesystem_creator.go file is getting too large; this change separates
the filesystem_module definition and the fsgen package mutators and
modules creation logic.

Test: m nothing --no-skip-soong-tests
Change-Id: I832d4369984f3e45eb92278ea3a091f8c47f467e
diff --git a/fsgen/fsgen_mutators.go b/fsgen/fsgen_mutators.go
new file mode 100644
index 0000000..096b132
--- /dev/null
+++ b/fsgen/fsgen_mutators.go
@@ -0,0 +1,342 @@
+// Copyright (C) 2024 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 fsgen
+
+import (
+	"android/soong/android"
+	"fmt"
+	"slices"
+	"sync"
+
+	"github.com/google/blueprint/proptools"
+)
+
+func RegisterCollectFileSystemDepsMutators(ctx android.RegisterMutatorsContext) {
+	ctx.BottomUp("fs_collect_deps", collectDepsMutator).MutatesGlobalState()
+	ctx.BottomUp("fs_set_deps", setDepsMutator)
+}
+
+var fsGenStateOnceKey = android.NewOnceKey("FsGenState")
+var fsGenRemoveOverridesOnceKey = android.NewOnceKey("FsGenRemoveOverrides")
+
+// Map of partition module name to its partition that may be generated by Soong.
+// Note that it is not guaranteed that all modules returned by this function are successfully
+// created.
+func getAllSoongGeneratedPartitionNames(config android.Config, partitions []string) map[string]string {
+	ret := map[string]string{}
+	for _, partition := range partitions {
+		ret[generatedModuleNameForPartition(config, partition)] = partition
+	}
+	return ret
+}
+
+type depCandidateProps struct {
+	Namespace string
+	Multilib  string
+	Arch      []android.ArchType
+}
+
+// Map of module name to depCandidateProps
+type multilibDeps map[string]*depCandidateProps
+
+// Information necessary to generate the filesystem modules, including details about their
+// dependencies
+type FsGenState struct {
+	// List of modules in `PRODUCT_PACKAGES` and `PRODUCT_PACKAGES_DEBUG`
+	depCandidates []string
+	// Map of names of partition to the information of modules to be added as deps
+	fsDeps map[string]*multilibDeps
+	// List of name of partitions to be generated by the filesystem_creator module
+	soongGeneratedPartitions []string
+	// Mutex to protect the fsDeps
+	fsDepsMutex sync.Mutex
+	// Map of _all_ soong module names to their corresponding installation properties
+	moduleToInstallationProps map[string]installationProperties
+}
+
+type installationProperties struct {
+	Required  []string
+	Overrides []string
+}
+
+func defaultDepCandidateProps(config android.Config) *depCandidateProps {
+	return &depCandidateProps{
+		Namespace: ".",
+		Arch:      []android.ArchType{config.BuildArch},
+	}
+}
+
+func generatedPartitions(ctx android.LoadHookContext) []string {
+	generatedPartitions := []string{"system"}
+	if ctx.DeviceConfig().SystemExtPath() == "system_ext" {
+		generatedPartitions = append(generatedPartitions, "system_ext")
+	}
+	if ctx.DeviceConfig().BuildingVendorImage() && ctx.DeviceConfig().VendorPath() == "vendor" {
+		generatedPartitions = append(generatedPartitions, "vendor")
+	}
+	if ctx.DeviceConfig().BuildingProductImage() && ctx.DeviceConfig().ProductPath() == "product" {
+		generatedPartitions = append(generatedPartitions, "product")
+	}
+	if ctx.DeviceConfig().BuildingOdmImage() && ctx.DeviceConfig().OdmPath() == "odm" {
+		generatedPartitions = append(generatedPartitions, "odm")
+	}
+	if ctx.Config().ProductVariables().PartitionVarsForSoongMigrationOnlyDoNotUse.BuildingSystemDlkmImage {
+		generatedPartitions = append(generatedPartitions, "system_dlkm")
+	}
+	return generatedPartitions
+}
+
+func createFsGenState(ctx android.LoadHookContext, generatedPrebuiltEtcModuleNames []string) *FsGenState {
+	return ctx.Config().Once(fsGenStateOnceKey, func() interface{} {
+		partitionVars := ctx.Config().ProductVariables().PartitionVarsForSoongMigrationOnlyDoNotUse
+		candidates := android.FirstUniqueStrings(android.Concat(partitionVars.ProductPackages, partitionVars.ProductPackagesDebug))
+		candidates = android.Concat(candidates, generatedPrebuiltEtcModuleNames)
+
+		return &FsGenState{
+			depCandidates: candidates,
+			fsDeps: map[string]*multilibDeps{
+				// These additional deps are added according to the cuttlefish system image bp.
+				"system": {
+					"com.android.apex.cts.shim.v1_prebuilt":     defaultDepCandidateProps(ctx.Config()),
+					"dex_bootjars":                              defaultDepCandidateProps(ctx.Config()),
+					"framework_compatibility_matrix.device.xml": defaultDepCandidateProps(ctx.Config()),
+					"init.environ.rc-soong":                     defaultDepCandidateProps(ctx.Config()),
+					"libclang_rt.asan":                          defaultDepCandidateProps(ctx.Config()),
+					"libcompiler_rt":                            defaultDepCandidateProps(ctx.Config()),
+					"libdmabufheap":                             defaultDepCandidateProps(ctx.Config()),
+					"libgsi":                                    defaultDepCandidateProps(ctx.Config()),
+					"llndk.libraries.txt":                       defaultDepCandidateProps(ctx.Config()),
+					"logpersist.start":                          defaultDepCandidateProps(ctx.Config()),
+					"update_engine_sideload":                    defaultDepCandidateProps(ctx.Config()),
+				},
+				"vendor": {
+					"fs_config_files_vendor":                               defaultDepCandidateProps(ctx.Config()),
+					"fs_config_dirs_vendor":                                defaultDepCandidateProps(ctx.Config()),
+					generatedModuleName(ctx.Config(), "vendor-build.prop"): defaultDepCandidateProps(ctx.Config()),
+				},
+				"odm": {
+					// fs_config_* files are automatically installed for all products with odm partitions.
+					// https://cs.android.com/android/_/android/platform/build/+/e4849e87ab660b59a6501b3928693db065ee873b:tools/fs_config/Android.mk;l=34;drc=8d6481b92c4b4e9b9f31a61545b6862090fcc14b;bpv=1;bpt=0
+					"fs_config_files_odm": defaultDepCandidateProps(ctx.Config()),
+					"fs_config_dirs_odm":  defaultDepCandidateProps(ctx.Config()),
+				},
+				"product": {},
+				"system_ext": {
+					// VNDK apexes are automatically included.
+					// This hardcoded list will need to be updated if `PRODUCT_EXTRA_VNDK_VERSIONS` is updated.
+					// https://cs.android.com/android/_/android/platform/build/+/adba533072b00c53ac0f198c550a3cbd7a00e4cd:core/main.mk;l=984;bpv=1;bpt=0;drc=174db7b179592cf07cbfd2adb0119486fda911e7
+					"com.android.vndk.v30": defaultDepCandidateProps(ctx.Config()),
+					"com.android.vndk.v31": defaultDepCandidateProps(ctx.Config()),
+					"com.android.vndk.v32": defaultDepCandidateProps(ctx.Config()),
+					"com.android.vndk.v33": defaultDepCandidateProps(ctx.Config()),
+					"com.android.vndk.v34": defaultDepCandidateProps(ctx.Config()),
+				},
+				"system_dlkm": {},
+			},
+			soongGeneratedPartitions:  generatedPartitions(ctx),
+			fsDepsMutex:               sync.Mutex{},
+			moduleToInstallationProps: map[string]installationProperties{},
+		}
+	}).(*FsGenState)
+}
+
+func checkDepModuleInMultipleNamespaces(mctx android.BottomUpMutatorContext, foundDeps multilibDeps, module string, partitionName string) {
+	otherNamespace := mctx.Namespace().Path
+	if val, found := foundDeps[module]; found && otherNamespace != "." && !android.InList(val.Namespace, []string{".", otherNamespace}) {
+		mctx.ModuleErrorf("found in multiple namespaces(%s and %s) when including in %s partition", val.Namespace, otherNamespace, partitionName)
+	}
+}
+
+func appendDepIfAppropriate(mctx android.BottomUpMutatorContext, deps *multilibDeps, installPartition string) {
+	checkDepModuleInMultipleNamespaces(mctx, *deps, mctx.Module().Name(), installPartition)
+	if _, ok := (*deps)[mctx.Module().Name()]; ok {
+		// Prefer the namespace-specific module over the platform module
+		if mctx.Namespace().Path != "." {
+			(*deps)[mctx.Module().Name()].Namespace = mctx.Namespace().Path
+		}
+		(*deps)[mctx.Module().Name()].Arch = append((*deps)[mctx.Module().Name()].Arch, mctx.Module().Target().Arch.ArchType)
+	} else {
+		multilib, _ := mctx.Module().DecodeMultilib(mctx)
+		(*deps)[mctx.Module().Name()] = &depCandidateProps{
+			Namespace: mctx.Namespace().Path,
+			Multilib:  multilib,
+			Arch:      []android.ArchType{mctx.Module().Target().Arch.ArchType},
+		}
+	}
+}
+
+func collectDepsMutator(mctx android.BottomUpMutatorContext) {
+	fsGenState := mctx.Config().Get(fsGenStateOnceKey).(*FsGenState)
+
+	m := mctx.Module()
+	if m.Target().Os.Class == android.Device && slices.Contains(fsGenState.depCandidates, m.Name()) {
+		installPartition := m.PartitionTag(mctx.DeviceConfig())
+		fsGenState.fsDepsMutex.Lock()
+		// Only add the module as dependency when:
+		// - its enabled
+		// - its namespace is included in PRODUCT_SOONG_NAMESPACES
+		if m.Enabled(mctx) && m.ExportedToMake() {
+			appendDepIfAppropriate(mctx, fsGenState.fsDeps[installPartition], installPartition)
+		}
+		fsGenState.fsDepsMutex.Unlock()
+	}
+	// store the map of module to (required,overrides) even if the module is not in PRODUCT_PACKAGES.
+	// the module might be installed transitively.
+	if m.Target().Os.Class == android.Device && m.Enabled(mctx) && m.ExportedToMake() {
+		fsGenState.fsDepsMutex.Lock()
+		fsGenState.moduleToInstallationProps[m.Name()] = installationProperties{
+			Required:  m.RequiredModuleNames(mctx),
+			Overrides: m.Overrides(),
+		}
+		fsGenState.fsDepsMutex.Unlock()
+	}
+}
+
+type depsStruct struct {
+	Deps []string
+}
+
+type multilibDepsStruct struct {
+	Common   depsStruct
+	Lib32    depsStruct
+	Lib64    depsStruct
+	Both     depsStruct
+	Prefer32 depsStruct
+}
+
+type packagingPropsStruct struct {
+	High_priority_deps []string
+	Deps               []string
+	Multilib           multilibDepsStruct
+}
+
+func fullyQualifiedModuleName(moduleName, namespace string) string {
+	if namespace == "." {
+		return moduleName
+	}
+	return fmt.Sprintf("//%s:%s", namespace, moduleName)
+}
+
+func getBitness(archTypes []android.ArchType) (ret []string) {
+	for _, archType := range archTypes {
+		if archType.Multilib == "" {
+			ret = append(ret, android.COMMON_VARIANT)
+		} else {
+			ret = append(ret, archType.Bitness())
+		}
+	}
+	return ret
+}
+
+func setDepsMutator(mctx android.BottomUpMutatorContext) {
+	removeOverriddenDeps(mctx)
+	fsGenState := mctx.Config().Get(fsGenStateOnceKey).(*FsGenState)
+	fsDeps := fsGenState.fsDeps
+	soongGeneratedPartitionMap := getAllSoongGeneratedPartitionNames(mctx.Config(), fsGenState.soongGeneratedPartitions)
+	m := mctx.Module()
+	if partition, ok := soongGeneratedPartitionMap[m.Name()]; ok {
+		depsStruct := generateDepStruct(*fsDeps[partition])
+		if err := proptools.AppendMatchingProperties(m.GetProperties(), depsStruct, nil); err != nil {
+			mctx.ModuleErrorf(err.Error())
+		}
+	}
+}
+
+// removeOverriddenDeps collects PRODUCT_PACKAGES and (transitive) required deps.
+// it then removes any modules which appear in `overrides` of the above list.
+func removeOverriddenDeps(mctx android.BottomUpMutatorContext) {
+	mctx.Config().Once(fsGenRemoveOverridesOnceKey, func() interface{} {
+		fsGenState := mctx.Config().Get(fsGenStateOnceKey).(*FsGenState)
+		fsDeps := fsGenState.fsDeps
+		overridden := map[string]bool{}
+		allDeps := []string{}
+
+		// Step 1: Initialization: Append PRODUCT_PACKAGES to the queue
+		for _, fsDep := range fsDeps {
+			for depName, _ := range *fsDep {
+				allDeps = append(allDeps, depName)
+			}
+		}
+
+		// Step 2: Process the queue, and add required modules to the queue.
+		i := 0
+		for {
+			if i == len(allDeps) {
+				break
+			}
+			depName := allDeps[i]
+			for _, overrides := range fsGenState.moduleToInstallationProps[depName].Overrides {
+				overridden[overrides] = true
+			}
+			// add required dep to the queue.
+			allDeps = append(allDeps, fsGenState.moduleToInstallationProps[depName].Required...)
+			i += 1
+		}
+
+		// Step 3: Delete all the overridden modules.
+		for overridden, _ := range overridden {
+			for partition, _ := range fsDeps {
+				delete(*fsDeps[partition], overridden)
+			}
+		}
+		return nil
+	})
+}
+
+var HighPriorityDeps = []string{}
+
+func generateDepStruct(deps map[string]*depCandidateProps) *packagingPropsStruct {
+	depsStruct := packagingPropsStruct{}
+	for depName, depProps := range deps {
+		bitness := getBitness(depProps.Arch)
+		fullyQualifiedDepName := fullyQualifiedModuleName(depName, depProps.Namespace)
+		if android.InList(depName, HighPriorityDeps) {
+			depsStruct.High_priority_deps = append(depsStruct.High_priority_deps, fullyQualifiedDepName)
+		} else if android.InList("32", bitness) && android.InList("64", bitness) {
+			// If both 32 and 64 bit variants are enabled for this module
+			switch depProps.Multilib {
+			case string(android.MultilibBoth):
+				depsStruct.Multilib.Both.Deps = append(depsStruct.Multilib.Both.Deps, fullyQualifiedDepName)
+			case string(android.MultilibCommon), string(android.MultilibFirst):
+				depsStruct.Deps = append(depsStruct.Deps, fullyQualifiedDepName)
+			case "32":
+				depsStruct.Multilib.Lib32.Deps = append(depsStruct.Multilib.Lib32.Deps, fullyQualifiedDepName)
+			case "64", "darwin_universal":
+				depsStruct.Multilib.Lib64.Deps = append(depsStruct.Multilib.Lib64.Deps, fullyQualifiedDepName)
+			case "prefer32", "first_prefer32":
+				depsStruct.Multilib.Prefer32.Deps = append(depsStruct.Multilib.Prefer32.Deps, fullyQualifiedDepName)
+			default:
+				depsStruct.Multilib.Both.Deps = append(depsStruct.Multilib.Both.Deps, fullyQualifiedDepName)
+			}
+		} else if android.InList("64", bitness) {
+			// If only 64 bit variant is enabled
+			depsStruct.Multilib.Lib64.Deps = append(depsStruct.Multilib.Lib64.Deps, fullyQualifiedDepName)
+		} else if android.InList("32", bitness) {
+			// If only 32 bit variant is enabled
+			depsStruct.Multilib.Lib32.Deps = append(depsStruct.Multilib.Lib32.Deps, fullyQualifiedDepName)
+		} else {
+			// If only common variant is enabled
+			depsStruct.Multilib.Common.Deps = append(depsStruct.Multilib.Common.Deps, fullyQualifiedDepName)
+		}
+	}
+	depsStruct.Deps = android.SortedUniqueStrings(depsStruct.Deps)
+	depsStruct.Multilib.Lib32.Deps = android.SortedUniqueStrings(depsStruct.Multilib.Lib32.Deps)
+	depsStruct.Multilib.Lib64.Deps = android.SortedUniqueStrings(depsStruct.Multilib.Lib64.Deps)
+	depsStruct.Multilib.Prefer32.Deps = android.SortedUniqueStrings(depsStruct.Multilib.Prefer32.Deps)
+	depsStruct.Multilib.Both.Deps = android.SortedUniqueStrings(depsStruct.Multilib.Both.Deps)
+	depsStruct.Multilib.Common.Deps = android.SortedUniqueStrings(depsStruct.Multilib.Common.Deps)
+
+	return &depsStruct
+}