1// Copyright 2020 Google Inc. All rights reserved.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15package bp2build
16
17import (
18	"android/soong/android"
19	"fmt"
20	"os"
21)
22
23// Codegen is the backend of bp2build. The code generator is responsible for
24// writing .bzl files that are equivalent to Android.bp files that are capable
25// of being built with Bazel.
26func Codegen(ctx *CodegenContext) CodegenMetrics {
27	// This directory stores BUILD files that could be eventually checked-in.
28	bp2buildDir := android.PathForOutput(ctx, "bp2build")
29	android.RemoveAllOutputDir(bp2buildDir)
30
31	buildToTargets, metrics := GenerateBazelTargets(ctx, true)
32	bp2buildFiles := CreateBazelFiles(nil, buildToTargets, ctx.mode)
33	writeFiles(ctx, bp2buildDir, bp2buildFiles)
34
35	soongInjectionDir := android.PathForOutput(ctx, "soong_injection")
36	writeFiles(ctx, soongInjectionDir, CreateSoongInjectionFiles())
37
38	return metrics
39}
40
41// Get the output directory and create it if it doesn't exist.
42func getOrCreateOutputDir(outputDir android.OutputPath, ctx android.PathContext, dir string) android.OutputPath {
43	dirPath := outputDir.Join(ctx, dir)
44	android.CreateOutputDirIfNonexistent(dirPath, os.ModePerm)
45	return dirPath
46}
47
48// writeFiles materializes a list of BazelFile rooted at outputDir.
49func writeFiles(ctx android.PathContext, outputDir android.OutputPath, files []BazelFile) {
50	for _, f := range files {
51		p := getOrCreateOutputDir(outputDir, ctx, f.Dir).Join(ctx, f.Basename)
52		if err := writeFile(ctx, p, f.Contents); err != nil {
53			panic(fmt.Errorf("Failed to write %q (dir %q) due to %q", f.Basename, f.Dir, err))
54		}
55	}
56}
57
58func writeFile(ctx android.PathContext, pathToFile android.OutputPath, content string) error {
59	// These files are made editable to allow users to modify and iterate on them
60	// in the source tree.
61	return android.WriteFileToOutputDir(pathToFile, []byte(content), 0644)
62}
63