cmd/pom2mk/pom2mk.go

// Copyright 2017 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 main

import (
	"encoding/xml"
	"flag"
	"fmt"
	"io/ioutil"
	"os"
	"path/filepath"
	"regexp"
	"sort"
	"strings"
	"text/template"

	"github.com/google/blueprint/proptools"
)

type RewriteNames []RewriteName
type RewriteName struct {
	regexp *regexp.Regexp
	repl   string
}

func (r *RewriteNames) String() string {
	return ""
}

func (r *RewriteNames) Set(v string) error {
	split := strings.SplitN(v, "=", 2)
	if len(split) != 2 {
		return fmt.Errorf("Must be in the form of <regex>=<replace>")
	}
	regex, err := regexp.Compile(split[0])
	if err != nil {
		return nil
	}
	*r = append(*r, RewriteName{
		regexp: regex,
		repl:   split[1],
	})
	return nil
}

func (r *RewriteNames) MavenToMk(groupId string, artifactId string) string {
	for _, r := range *r {
		if r.regexp.MatchString(groupId + ":" + artifactId) {
			return r.regexp.ReplaceAllString(groupId+":"+artifactId, r.repl)
		} else if r.regexp.MatchString(artifactId) {
			return r.regexp.ReplaceAllString(artifactId, r.repl)
		}
	}
	return artifactId
}

var rewriteNames = RewriteNames{}

type ExtraDeps map[string][]string

func (d ExtraDeps) String() string {
	return ""
}

func (d ExtraDeps) Set(v string) error {
	split := strings.SplitN(v, "=", 2)
	if len(split) != 2 {
		return fmt.Errorf("Must be in the form of <module>=<module>[,<module>]")
	}
	d[split[0]] = strings.Split(split[1], ",")
	return nil
}

var extraDeps = make(ExtraDeps)

var sdkVersion string
var useVersion string

type Dependency struct {
	XMLName xml.Name `xml:"dependency"`

	GroupId    string `xml:"groupId"`
	ArtifactId string `xml:"artifactId"`
	Version    string `xml:"version"`
	Type       string `xml:"type"`

	Scope string `xml:"scope"`
}

type Pom struct {
	XMLName xml.Name `xml:"http://maven.apache.org/POM/4.0.0 project"`

	PomFile      string `xml:"-"`
	ArtifactFile string `xml:"-"`
	MakeTarget   string `xml:"-"`

	GroupId    string `xml:"groupId"`
	ArtifactId string `xml:"artifactId"`
	Version    string `xml:"version"`
	Packaging  string `xml:"packaging"`

	Dependencies []*Dependency `xml:"dependencies>dependency"`
}

func (p Pom) MkName() string {
	if p.MakeTarget == "" {
		p.MakeTarget = rewriteNames.MavenToMk(p.GroupId, p.ArtifactId)
	}
	return p.MakeTarget
}

func (p Pom) MkDeps() []string {
	var ret []string
	for _, d := range p.Dependencies {
		if d.Type != "aar" {
			continue
		}
		name := rewriteNames.MavenToMk(d.GroupId, d.ArtifactId)
		ret = append(ret, name)
		ret = append(ret, extraDeps[name]...)
	}
	return ret
}

func (p Pom) SdkVersion() string {
	return sdkVersion
}

func (p *Pom) FixDepTypes(modules map[string]*Pom) {
	for _, d := range p.Dependencies {
		if d.Type != "" {
			continue
		}
		if depPom, ok := modules[p.MkName()]; ok {
			d.Type = depPom.Packaging
		}
	}
}

var mkTemplate = template.Must(template.New("mk").Parse(`
include $(CLEAR_VARS)
LOCAL_MODULE := {{.MkName}}
LOCAL_MODULE_CLASS := JAVA_LIBRARIES
LOCAL_UNINSTALLABLE_MODULE := true
LOCAL_SRC_FILES := {{.ArtifactFile}}
LOCAL_BUILT_MODULE_STEM := javalib.jar
LOCAL_MODULE_SUFFIX := .{{.Packaging}}
LOCAL_USE_AAPT2 := true
LOCAL_SDK_VERSION := {{.SdkVersion}}
LOCAL_STATIC_ANDROID_LIBRARIES := \
{{range .MkDeps}}  {{.}} \
{{end}}
include $(BUILD_PREBUILT)
`))

func parse(filename string) (*Pom, error) {
	data, err := ioutil.ReadFile(filename)
	if err != nil {
		return nil, err
	}

	var pom Pom
	err = xml.Unmarshal(data, &pom)
	if err != nil {
		return nil, err
	}

	if useVersion != "" && pom.Version != useVersion {
		return nil, nil
	}

	if pom.Packaging == "" {
		pom.Packaging = "jar"
	}

	pom.PomFile = filename
	pom.ArtifactFile = strings.TrimSuffix(filename, ".pom") + "." + pom.Packaging

	return &pom, nil
}

func main() {
	flag.Usage = func() {
		fmt.Fprintf(os.Stderr, `pom2mk, a tool to create Android.mk files from maven repos

The tool will extract the necessary information from *.pom files to create an Android.mk whose
aar libraries can be linked against when using AAPT2.

Usage: %s [--rewrite <regex>=<replace>] [--extra-deps <module>=<module>[,<module>]] <dir>

  -rewrite <regex>=<replace>
     rewrite can be used to specify mappings between Maven projects and Make modules. The -rewrite
     option can be specified multiple times. When determining the Make module for a given Maven
     project, mappings are searched in the order they were specified. The first <regex> matching
     either the Maven project's <groupId>:<artifactId> or <artifactId> will be used to generate
     the Make module name using <replace>. If no matches are found, <artifactId> is used.
  -extra-deps <module>=<module>[,<module>]
     Some Android.mk modules have transitive dependencies that must be specified when they are
     depended upon (like android-support-v7-mediarouter requires android-support-v7-appcompat).
     This may be specified multiple times to declare these dependencies.
  -sdk-version <version>
     Sets LOCAL_SDK_VERSION := <version> for all modules.
  -use-version <version>
     If the maven directory contains multiple versions of artifacts and their pom files,
     -use-version can be used to only write makefiles for a specific version of those artifacts.
  <dir>
     The directory to search for *.pom files under.

The makefile is written to stdout, to be put in the current directory (often as Android.mk)
`, os.Args[0])
	}

	flag.Var(&extraDeps, "extra-deps", "Extra dependencies needed when depending on a module")
	flag.Var(&rewriteNames, "rewrite", "Regex(es) to rewrite artifact names")
	flag.StringVar(&sdkVersion, "sdk-version", "", "What to write to LOCAL_SDK_VERSION")
	flag.StringVar(&useVersion, "use-version", "", "Only read artifacts of a specific version")
	flag.Parse()

	if flag.NArg() != 1 {
		flag.Usage()
		os.Exit(1)
	}

	dir := flag.Arg(0)
	absDir, err := filepath.Abs(dir)
	if err != nil {
		fmt.Println(os.Stderr, "Failed to get absolute directory:", err)
		os.Exit(1)
	}

	var filenames []string
	err = filepath.Walk(absDir, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}

		name := info.Name()
		if info.IsDir() {
			if strings.HasPrefix(name, ".") {
				return filepath.SkipDir
			}
			return nil
		}

		if strings.HasPrefix(name, ".") {
			return nil
		}

		if strings.HasSuffix(name, ".pom") {
			path, err = filepath.Rel(absDir, path)
			if err != nil {
				return err
			}
			filenames = append(filenames, filepath.Join(dir, path))
		}
		return nil
	})
	if err != nil {
		fmt.Fprintln(os.Stderr, "Error walking files:", err)
		os.Exit(1)
	}

	if len(filenames) == 0 {
		fmt.Fprintln(os.Stderr, "Error: no *.pom files found under", dir)
		os.Exit(1)
	}

	sort.Strings(filenames)

	poms := []*Pom{}
	modules := make(map[string]*Pom)
	for _, filename := range filenames {
		pom, err := parse(filename)
		if err != nil {
			fmt.Fprintln(os.Stderr, "Error converting", filename, err)
			os.Exit(1)
		}

		if pom != nil {
			poms = append(poms, pom)
			key := pom.MkName()

			if old, ok := modules[key]; ok {
				fmt.Fprintln(os.Stderr, "Module", key, "defined twice:", old.PomFile, pom.PomFile)
				os.Exit(1)
			}

			modules[key] = pom
		}
	}

	for _, pom := range poms {
		pom.FixDepTypes(modules)
	}

	fmt.Println("# Automatically generated with:")
	fmt.Println("# pom2mk", strings.Join(proptools.ShellEscape(os.Args[1:]), " "))
	fmt.Println("LOCAL_PATH := $(call my-dir)")

	for _, pom := range poms {
		err := mkTemplate.Execute(os.Stdout, pom)
		if err != nil {
			fmt.Fprintln(os.Stderr, "Error writing", pom.PomFile, pom.MkName(), err)
			os.Exit(1)
		}
	}
}