Add module based host-tools snapshot

Add new module:
host_snapshot {
    name: "host-snapshot"
    deps: [
      (list of host tools)
    ],
    ...
}

Package host tools using android.PackagingBase to capture host tools and transitive packaging data.
Add JSON meta data to snapshot that allows snapshot to be installed via development/vendor_snapshot/update.py

Add support to generate a fake host snapshot of all host modules that is used to detect required
modules via development/vendor_snapshot/update.py.

Bug: 192556798
Bug: 194799048
Bug: 192896149
Test: m HOST_FAKE_SNAPSHOT_ENABLE=true host-fake-snapshot dist -- check snapshot exists in dist

Change-Id: I849c4db801cd858408f6fe6a3ce69262a23a5be9

snapshot/host_test.go

@@ -0,0 +1,170 @@
+// 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 (
+	"path/filepath"
+	"testing"
+
+	"android/soong/android"
+)
+
+// host_snapshot and host-fake-snapshot test functions
+
+type hostTestModule struct {
+	android.ModuleBase
+	props struct {
+		Deps []string
+	}
+}
+
+func hostTestBinOut(bin string) string {
+	return filepath.Join("out", "bin", bin)
+}
+
+func (c *hostTestModule) HostToolPath() android.OptionalPath {
+	return (android.OptionalPathForPath(android.PathForTesting(hostTestBinOut(c.Name()))))
+}
+
+func hostTestModuleFactory() android.Module {
+	m := &hostTestModule{}
+	m.AddProperties(&m.props)
+	android.InitAndroidArchModule(m, android.HostSupported, android.MultilibFirst)
+	return m
+}
+func (m *hostTestModule) GenerateAndroidBuildActions(ctx android.ModuleContext) {
+	builtFile := android.PathForModuleOut(ctx, m.Name())
+	dir := ctx.Target().Arch.ArchType.Multilib
+	installDir := android.PathForModuleInstall(ctx, dir)
+	ctx.InstallFile(installDir, m.Name(), builtFile)
+}
+
+// Common blueprint used for testing
+var hostTestBp = `
+		license_kind {
+			name: "test_notice",
+			conditions: ["notice"],
+		}
+		license {
+			name: "host_test_license",
+			visibility: ["//visibility:public"],
+			license_kinds: [
+				"test_notice"
+			],
+			license_text: [
+				"NOTICE",
+			],
+		}
+		component {
+			name: "foo",
+			deps: ["bar"],
+		}
+		component {
+			name: "bar",
+			licenses: ["host_test_license"],
+		}
+		`
+
+var hostTestModBp = `
+		host_snapshot {
+			name: "test-host-snapshot",
+			deps: [
+				"foo",
+			],
+		}
+		`
+
+var prepareForHostTest = android.GroupFixturePreparers(
+	android.PrepareForTestWithAndroidBuildComponents,
+	android.PrepareForTestWithLicenses,
+	android.FixtureRegisterWithContext(func(ctx android.RegistrationContext) {
+		ctx.RegisterModuleType("component", hostTestModuleFactory)
+	}),
+)
+
+// Prepare for host_snapshot test
+var prepareForHostModTest = android.GroupFixturePreparers(
+	prepareForHostTest,
+	android.FixtureWithRootAndroidBp(hostTestBp+hostTestModBp),
+	android.FixtureRegisterWithContext(func(ctx android.RegistrationContext) {
+		registerHostBuildComponents(ctx)
+	}),
+)
+
+// Prepare for fake host snapshot test disabled
+var prepareForFakeHostTest = android.GroupFixturePreparers(
+	prepareForHostTest,
+	android.FixtureWithRootAndroidBp(hostTestBp),
+	android.FixtureRegisterWithContext(func(ctx android.RegistrationContext) {
+		registerHostSnapshotComponents(ctx)
+	}),
+)
+
+// Prepare for fake host snapshot test enabled
+var prepareForFakeHostTestEnabled = android.GroupFixturePreparers(
+	prepareForFakeHostTest,
+	android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
+		variables.HostFakeSnapshotEnabled = true
+	}),
+)
+
+// Validate that a hostSnapshot object is created containing zip files and JSON file
+// content of zip file is not validated as this is done by PackagingSpecs
+func TestHostSnapshot(t *testing.T) {
+	result := prepareForHostModTest.RunTest(t)
+	t.Helper()
+	ctx := result.TestContext.ModuleForTests("test-host-snapshot", result.Config.BuildOS.String()+"_common")
+	mod := ctx.Module().(*hostSnapshot)
+	if ctx.MaybeOutput("host_snapshot.json").Rule == nil {
+		t.Error("Manifest file not found")
+	}
+	zips := []string{"_deps.zip", "_mods.zip", ".zip"}
+
+	for _, zip := range zips {
+		zFile := mod.Name() + zip
+		if ctx.MaybeOutput(zFile).Rule == nil {
+			t.Error("Zip file ", zFile, "not found")
+		}
+
+	}
+}
+
+// Validate fake host snapshot contains binary modules as well as the JSON meta file
+func TestFakeHostSnapshotEnable(t *testing.T) {
+	result := prepareForFakeHostTestEnabled.RunTest(t)
+	t.Helper()
+	bins := []string{"foo", "bar"}
+	ctx := result.TestContext.SingletonForTests("host-fake-snapshot")
+	if ctx.MaybeOutput(filepath.Join("host-fake-snapshot", "host_snapshot.json")).Rule == nil {
+		t.Error("Manifest file not found")
+	}
+	for _, bin := range bins {
+		if ctx.MaybeOutput(filepath.Join("host-fake-snapshot", hostTestBinOut(bin))).Rule == nil {
+			t.Error("Binary file ", bin, "not found")
+		}
+
+	}
+}
+
+// Validate not fake host snapshot if HostFakeSnapshotEnabled has not been set to true
+func TestFakeHostSnapshotDisable(t *testing.T) {
+	result := prepareForFakeHostTest.RunTest(t)
+	t.Helper()
+	ctx := result.TestContext.SingletonForTests("host-fake-snapshot")
+	if len(ctx.AllOutputs()) != 0 {
+		t.Error("Fake host snapshot not empty when disabled")
+	}
+
+}