strip_google_play_services.gradle

import groovy.transform.Field

// This is a drop-in Gradle script that allows you to easily strip out the packages you don't need
// from the Google Play Services library. The script will keep track of previous runs to prevent
// restripping each time you build.

// HOW TO USE THIS
//
// 1) Download/copy this strip_google_play_services.gradle file into the same location of your app's
//    build.gradle file.
//
// 2) In your app's build.gradle file, add the following underneath the Android application plugin
//    declaration:
//
//          apply plugin: 'com.android.application'
//          apply from: 'strip_google_play_services.gradle'          <--- ADD THIS
//
// 3) Tweak the packagesToStrip map to suit your needs. Set the boolean value to 'false' if you'd
//    like the package to NOT be stripped.
//
// 4) Optional: Add or remove items from the additionalPackagesToStrip map. The current value in
//    there does not have the same package prefix as the rest.

// NOTE: The packages list below are based on the Google Play Services package index found at the
// following location: http://developer.android.com/reference/gms-packages.html
// This list is current as of version 6.1.71.
//
// The 'common' package was not included in the list because its... well... common to all packages
// and cannot be removed.

// THANKS to Dario Marcato & Cedric Gatay for providing the starting point.

@Field packagesToStrip = [
        'actions'       : true,
        'ads'           : false,
        'analytics'     : true,
        'appindexing'   : true,
        'appstate'      : true,
        'auth'          : true,
        'cast'          : true,
        'drive'         : true,
        'fitness'       : true,
        'games'         : true,
        'gcm'           : true,
        'identity'      : true,
        'location'      : true,
        'maps'          : true,
        'panorama'      : true,
        'plus'          : true,
        'security'      : true,
        'tagmanager'    : true,
        'wallet'        : true,
        'wearable'      : true
]
@Field additionalPackagesToStrip = [
        "com/google/ads/**"
]

@Field packageFormat = "com/google/android/gms/PACKAGE_NAME/**"

def toCamelCase(String string) {
    String result = ""
    string.findAll("[^\\W]+") { String word ->
        result += word.capitalize()
    }
    return result
}

def getPackageListToExclude() {
    def packageListToExclude = []
    for (item in packagesToStrip) {
        if (item.value == true) {
            packageListToExclude.add(packageFormat.replaceFirst(/PACKAGE_NAME/, item.key))
        }
    }
    if (additionalPackagesToStrip.size() > 0) {
        packageListToExclude.addAll(additionalPackagesToStrip)
    }
    return packageListToExclude
}

afterEvaluate { project ->
    Configuration runtimeConfiguration = project.configurations.getByName('compile')
    println runtimeConfiguration
    ResolutionResult resolution = runtimeConfiguration.incoming.resolutionResult
    // Forces resolve of configuration
    ModuleVersionIdentifier module = resolution.getAllComponents().find {
        it.moduleVersion.name.equals("play-services")
    }.moduleVersion

    def playServicesLibName = toCamelCase("${module.group} ${module.name} ${module.version}")
    String prepareTaskName = "prepare${playServicesLibName}Library"
    File playServiceRootFolder = project.tasks.find { it.name.equals(prepareTaskName) }.explodedDir

    def packageListToExclude = getPackageListToExclude()

    def tmpDir = new File(project.buildDir, 'intermediates/tmp')
    tmpDir.mkdirs()
    def libFile = new File(tmpDir, "${playServicesLibName}.marker")

    def strippedClassFileName = "${playServicesLibName}.jar"
    def classesStrippedJar = new File(tmpDir, strippedClassFileName)

    Task stripPlayServices = project.tasks.create(name: 'stripPlayServices', group: "Strip") {
        inputs.files new File(playServiceRootFolder, "classes.jar")
        outputs.dir playServiceRootFolder
        description 'Strip useless packages from Google Play Services library to avoid reaching dex limit'

        doLast {
            def packageExcludesAsString = packageListToExclude.join(",")
            if (libFile.exists()
                    && libFile.text == packageExcludesAsString
                    && classesStrippedJar.exists()){
                println "Play services already stripped"
                copy {
                    from(file(classesStrippedJar))
                    into(file(playServiceRootFolder))
                    rename { fileName ->
                        fileName = "classes.jar"
                    }
                }
            }else {
                copy {
                    from(file(new File(playServiceRootFolder, "classes.jar")))
                    into(file(playServiceRootFolder))
                    rename { fileName ->
                        fileName = "classes_orig.jar"
                    }
                }
                tasks.create(name: "stripPlayServices" + module.version, type: Jar) {
                    destinationDir = playServiceRootFolder
                    archiveName = "classes.jar"
                    from(zipTree(new File(playServiceRootFolder, "classes_orig.jar"))) {
                        exclude packageListToExclude
                    }
                }.execute()
                delete file(new File(playServiceRootFolder, "classes_orig.jar"))
                copy {
                    from(file(new File(playServiceRootFolder, "classes.jar")))
                    into(file(tmpDir))
                    rename { fileName ->
                        fileName = strippedClassFileName
                    }
                }
                libFile.text = packageExcludesAsString
            }
        }
    }

    project.tasks.findAll {
        it.name.startsWith('prepare') && it.name.endsWith('Dependencies')
    }.each { Task task ->
        task.dependsOn stripPlayServices
    }
}