Collect modules' info to create IDE project file.

- Register a singleton and implement GenerateBuildActions func in java/jdeps.go.
- Declare a interface and a struct to collect info in android/module.go.
- Implement IDEInfo for Library & Import module in java/jdeps.go.
- Implement IDEInfo for Genrule module in genrule/genrule.go.
- Implement IDEInfo for fileGroup module in android/filegroup.go.
- Test codes for jdeps.go in java/jdeps_test.go.

Bug: 111044346

Test: export SOONG_COLLECT_JAVA_DEPS=1;mmm packages/apps/Settings
      out/soong/module_bp_java_deps.json will be generated

Change-Id: If61da77b4d7614c2c5da438b6af4c725ceccc5c3
diff --git a/java/jdeps.go b/java/jdeps.go
new file mode 100644
index 0000000..c7fa42a
--- /dev/null
+++ b/java/jdeps.go
@@ -0,0 +1,109 @@
+// Copyright 2018 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 java
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+
+	"android/soong/android"
+)
+
+// This singleton generates android java dependency into to a json file. It does so for each
+// blueprint Android.bp resulting in a java.Module when either make, mm, mma, mmm or mmma is
+// called. Dependency info file is generated in $OUT/module_bp_java_depend.json.
+
+func init() {
+	android.RegisterSingletonType("jdeps_generator", jDepsGeneratorSingleton)
+}
+
+func jDepsGeneratorSingleton() android.Singleton {
+	return &jdepsGeneratorSingleton{}
+}
+
+type jdepsGeneratorSingleton struct {
+}
+
+const (
+	// Environment variables used to modify behavior of this singleton.
+	envVariableCollectJavaDeps = "SOONG_COLLECT_JAVA_DEPS"
+	jdepsJsonFileName          = "module_bp_java_deps.json"
+)
+
+func (j *jdepsGeneratorSingleton) GenerateBuildActions(ctx android.SingletonContext) {
+	if !ctx.Config().IsEnvTrue(envVariableCollectJavaDeps) {
+		return
+	}
+
+	moduleInfos := make(map[string]android.IdeInfo)
+
+	ctx.VisitAllModules(func(module android.Module) {
+		ideInfoProvider, ok := module.(android.IDEInfo)
+		if !ok {
+			return
+		}
+		name := ideInfoProvider.BaseModuleName()
+		ideModuleNameProvider, ok := module.(android.IDECustomizedModuleName)
+		if ok {
+			name = ideModuleNameProvider.IDECustomizedModuleName()
+		}
+
+		dpInfo := moduleInfos[name]
+		ideInfoProvider.IDEInfo(&dpInfo)
+		dpInfo.Deps = android.FirstUniqueStrings(dpInfo.Deps)
+		dpInfo.Srcs = android.FirstUniqueStrings(dpInfo.Srcs)
+		dpInfo.Aidl_include_dirs = android.FirstUniqueStrings(dpInfo.Aidl_include_dirs)
+		dpInfo.Jarjar_rules = android.FirstUniqueStrings(dpInfo.Jarjar_rules)
+		dpInfo.Jars = android.FirstUniqueStrings(dpInfo.Jars)
+		moduleInfos[name] = dpInfo
+
+		mkProvider, ok := module.(android.AndroidMkDataProvider)
+		if !ok {
+			return
+		}
+		data := mkProvider.AndroidMk()
+		if data.Class != "" {
+			dpInfo.Classes = append(dpInfo.Classes, data.Class)
+		}
+		out := data.OutputFile.String()
+		if out != "" {
+			dpInfo.Installed_paths = append(dpInfo.Installed_paths, out)
+		}
+		dpInfo.Classes = android.FirstUniqueStrings(dpInfo.Classes)
+		dpInfo.Installed_paths = android.FirstUniqueStrings(dpInfo.Installed_paths)
+		moduleInfos[name] = dpInfo
+	})
+
+	jfpath := android.PathForOutput(ctx, jdepsJsonFileName).String()
+	err := createJsonFile(moduleInfos, jfpath)
+	if err != nil {
+		ctx.Errorf(err.Error())
+	}
+}
+
+func createJsonFile(moduleInfos map[string]android.IdeInfo, jfpath string) error {
+	file, err := os.Create(jfpath)
+	if err != nil {
+		return fmt.Errorf("Failed to create file: %s, relative: %v", jdepsJsonFileName, err)
+	}
+	defer file.Close()
+	buf, err := json.MarshalIndent(moduleInfos, "", "\t")
+	if err != nil {
+		return fmt.Errorf("Write file failed: %s, relative: %v", jdepsJsonFileName, err)
+	}
+	fmt.Fprintf(file, string(buf))
+	return nil
+}