Generate combined deps-info for all updatable modules.

Introduce a singleton apex rule to merge contents of individual
deps-info results into a single output file.

Bug: 149622332
Test: m
Change-Id: I4ab7e1a3527fead97a81a5a2cb0e1e93a429117c

apex/apex_singleton.go

@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2020 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 apex
+
+import (
+	"github.com/google/blueprint"
+
+	"android/soong/android"
+)
+
+func init() {
+	android.RegisterSingletonType("apex_depsinfo_singleton", apexDepsInfoSingletonFactory)
+}
+
+type apexDepsInfoSingleton struct {
+	// Output file with all flatlists from updatable modules' deps-info combined
+	updatableFlatListsPath android.OutputPath
+}
+
+func apexDepsInfoSingletonFactory() android.Singleton {
+	return &apexDepsInfoSingleton{}
+}
+
+var combineFilesRule = pctx.AndroidStaticRule("combineFilesRule",
+	blueprint.RuleParams{
+		Command:        "cat $out.rsp | xargs cat > $out",
+		Rspfile:        "$out.rsp",
+		RspfileContent: "$in",
+	},
+)
+
+func (s *apexDepsInfoSingleton) GenerateBuildActions(ctx android.SingletonContext) {
+	updatableFlatLists := android.Paths{}
+	ctx.VisitAllModules(func(module android.Module) {
+		if binaryInfo, ok := module.(android.ApexBundleDepsInfoIntf); ok {
+			if path := binaryInfo.FlatListPath(); path != nil {
+				if binaryInfo.Updatable() {
+					updatableFlatLists = append(updatableFlatLists, path)
+				}
+			}
+		}
+	})
+
+	s.updatableFlatListsPath = android.PathForOutput(ctx, "apex", "depsinfo", "updatable-flatlists.txt")
+	ctx.Build(pctx, android.BuildParams{
+		Rule:        combineFilesRule,
+		Description: "Generate " + s.updatableFlatListsPath.String(),
+		Inputs:      updatableFlatLists,
+		Output:      s.updatableFlatListsPath,
+	})
+}