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// Copyright 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 snapshot
import (
"encoding/json"
"path/filepath"
"android/soong/android"
)
// The host_snapshot module creates a snapshot of host tools to be used
// in a minimal source tree. In order to create the host_snapshot the
// user must explicitly list the modules to be included. The
// host-fake-snapshot, defined in this file, is a utility to help determine
// which host modules are being used in the minimal source tree.
//
// The host-fake-snapshot is designed to run in a full source tree and
// will result in a snapshot that contains an empty file for each host
// tool found in the tree. The fake snapshot is only used to determine
// the host modules that the minimal source tree depends on, hence the
// snapshot uses an empty file for each module and saves on having to
// actually build any tool to generate the snapshot. The fake snapshot
// is compatible with an actual host_snapshot and is installed into a
// minimal source tree via the development/vendor_snapshot/update.py
// script.
//
// After generating the fake snapshot and installing into the minimal
// source tree, the dependent modules are determined via the
// development/vendor_snapshot/update.py script (see script for more
// information). These modules are then used to define the actual
// host_snapshot to be used. This is a similar process to the other
// snapshots (vendor, recovery,...)
//
// Example
//
// Full source tree:
// 1/ Generate fake host snapshot
//
// Minimal source tree:
// 2/ Install the fake host snapshot
// 3/ List the host modules used from the snapshot
// 4/ Remove fake host snapshot
//
// Full source tree:
// 4/ Create host_snapshot with modules identified in step 3
//
// Minimal source tree:
// 5/ Install host snapshot
// 6/ Build
//
// The host-fake-snapshot is a singleton module, that will be built
// if HOST_FAKE_SNAPSHOT_ENABLE=true.
func init() {
registerHostSnapshotComponents(android.InitRegistrationContext)
}
// Add prebuilt information to snapshot data
type hostSnapshotFakeJsonFlags struct {
SnapshotJsonFlags
Prebuilt bool `json:",omitempty"`
}
func registerHostSnapshotComponents(ctx android.RegistrationContext) {
ctx.RegisterSingletonType("host-fake-snapshot", HostToolsFakeAndroidSingleton)
}
type hostFakeSingleton struct {
snapshotDir string
zipFile android.OptionalPath
}
func (c *hostFakeSingleton) init() {
c.snapshotDir = "host-fake-snapshot"
}
func HostToolsFakeAndroidSingleton() android.Singleton {
singleton := &hostFakeSingleton{}
singleton.init()
return singleton
}
func (c *hostFakeSingleton) GenerateBuildActions(ctx android.SingletonContext) {
if !ctx.DeviceConfig().HostFakeSnapshotEnabled() {
return
}
// Find all host binary modules add 'fake' versions to snapshot
var outputs android.Paths
seen := make(map[string]bool)
var jsonData []hostSnapshotFakeJsonFlags
prebuilts := make(map[string]bool)
ctx.VisitAllModules(func(module android.Module) {
if module.Target().Os != ctx.Config().BuildOSTarget.Os {
return
}
if module.Target().Arch.ArchType != ctx.Config().BuildOSTarget.Arch.ArchType {
return
}
if android.IsModulePrebuilt(module) {
// Add non-prebuilt module name to map of prebuilts
prebuilts[android.RemoveOptionalPrebuiltPrefix(module.Name())] = true
return
}
if !module.Enabled() || module.IsHideFromMake() {
return
}
apexInfo := ctx.ModuleProvider(module, android.ApexInfoProvider).(android.ApexInfo)
if !apexInfo.IsForPlatform() {
return
}
path := hostToolPath(module)
if path.Valid() && path.String() != "" {
outFile := filepath.Join(c.snapshotDir, path.String())
if !seen[outFile] {
seen[outFile] = true
outputs = append(outputs, WriteStringToFileRule(ctx, "", outFile))
jsonData = append(jsonData, hostSnapshotFakeJsonFlags{*hostJsonDesc(module), false})
}
}
})
// Update any module prebuilt information
for idx, _ := range jsonData {
if _, ok := prebuilts[jsonData[idx].ModuleName]; ok {
// Prebuilt exists for this module
jsonData[idx].Prebuilt = true
}
}
marsh, err := json.Marshal(jsonData)
if err != nil {
ctx.Errorf("host fake snapshot json marshal failure: %#v", err)
return
}
outputs = append(outputs, WriteStringToFileRule(ctx, string(marsh), filepath.Join(c.snapshotDir, "host_snapshot.json")))
c.zipFile = zipSnapshot(ctx, c.snapshotDir, c.snapshotDir, outputs)
}
func (c *hostFakeSingleton) MakeVars(ctx android.MakeVarsContext) {
if !c.zipFile.Valid() {
return
}
ctx.Phony(
"host-fake-snapshot",
c.zipFile.Path())
ctx.DistForGoal(
"host-fake-snapshot",
c.zipFile.Path())
}