build-logic: add android plugins

build-logic/android-plugins/build.gradle.kts

@@ -8,4 +8,16 @@ plugins {
   `kotlin-dsl-precompiled-script-plugins`
 }
 
-dependencies { implementation(libs.build.agp) }
+gradlePlugin {
+  plugins {
+    register("versioning") {
+      id = "com.github.android-password-store.versioning-plugin"
+      implementationClass = "versioning.VersioningPlugin"
+    }
+  }
+}
+
+dependencies {
+  implementation(libs.build.agp)
+  implementation(libs.build.semver)
+}

build-logic/android-plugins/src/main/kotlin/com.github.android-password-store.android-application.gradle.kts

@@ -8,6 +8,7 @@ import flavors.FlavorDimensions
 import flavors.ProductFlavors
 import flavors.configureSlimTests
 import org.gradle.kotlin.dsl.configure
+import signing.configureBuildSigning
 
 plugins {
   id("com.android.application")
@@ -60,4 +61,5 @@ extensions.configure<BaseAppModuleExtension> {
   }
 
   project.configureSlimTests()
+  project.configureBuildSigning()
 }

build-logic/android-plugins/src/main/kotlin/com.github.android-password-store.android-library.gradle.kts

@@ -4,10 +4,20 @@
  */
 
 import flavors.configureSlimTests
+import org.gradle.kotlin.dsl.provideDelegate
+import org.gradle.plugins.signing.SigningExtension
 
 plugins {
   id("com.android.library")
   id("com.github.android-password-store.android-common")
 }
 
-project.configureSlimTests()
+afterEvaluate {
+  project.configureSlimTests()
+
+  extensions.configure<SigningExtension> {
+    val signingKey: String? by project
+    val signingPassword: String? by project
+    useInMemoryPgpKeys(signingKey, signingPassword)
+  }
+}

build-logic/android-plugins/src/main/kotlin/signing/AppSigning.kt

@@ -0,0 +1,37 @@
+/*
+ * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+package signing
+
+import com.android.build.gradle.internal.dsl.BaseAppModuleExtension
+import java.util.Properties
+import org.gradle.api.Project
+import org.gradle.kotlin.dsl.configure
+import org.gradle.kotlin.dsl.provideDelegate
+
+private const val KEYSTORE_CONFIG_PATH = "keystore.properties"
+
+/** Configure signing for all build types. */
+@Suppress("UnstableApiUsage")
+internal fun Project.configureBuildSigning() {
+  val keystoreConfigFile = rootProject.layout.projectDirectory.file(KEYSTORE_CONFIG_PATH)
+  if (keystoreConfigFile.asFile.exists()) {
+    extensions.configure<BaseAppModuleExtension> {
+      val contents = providers.fileContents(keystoreConfigFile).asText.forUseAtConfigurationTime()
+      val keystoreProperties = Properties()
+      keystoreProperties.load(contents.get().byteInputStream())
+      signingConfigs {
+        register("release") {
+          keyAlias = keystoreProperties["keyAlias"] as String
+          keyPassword = keystoreProperties["keyPassword"] as String
+          storeFile = rootProject.file(keystoreProperties["storeFile"] as String)
+          storePassword = keystoreProperties["storePassword"] as String
+        }
+      }
+      val signingConfig = signingConfigs.getByName("release")
+      buildTypes.all { setSigningConfig(signingConfig) }
+    }
+  }
+}

build-logic/android-plugins/src/main/kotlin/versioning/VersioningPlugin.kt

@@ -0,0 +1,108 @@
+/*
+ * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+package versioning
+
+import com.android.build.gradle.internal.plugins.AppPlugin
+import com.vdurmont.semver4j.Semver
+import java.io.OutputStream
+import java.util.Properties
+import org.gradle.api.Plugin
+import org.gradle.api.Project
+
+private const val VERSIONING_PROP_FILE = "version.properties"
+private const val VERSIONING_PROP_VERSION_NAME = "versioning-plugin.versionName"
+private const val VERSIONING_PROP_VERSION_CODE = "versioning-plugin.versionCode"
+private const val VERSIONING_PROP_COMMENT =
+  """
+This file was automatically generated by 'versioning-plugin'. DO NOT EDIT MANUALLY.
+"""
+
+/**
+ * A Gradle [Plugin] that takes a [Project] with the [AppPlugin] applied and dynamically sets the
+ * versionCode and versionName properties based on values read from a [VERSIONING_PROP_FILE] file in
+ * the [Project.getBuildDir] directory. It also adds Gradle tasks to bump the major, minor, and
+ * patch versions along with one to prepare the next snapshot.
+ */
+@Suppress("UnstableApiUsage", "NAME_SHADOWING")
+class VersioningPlugin : Plugin<Project> {
+
+  /** Generate the Android 'versionCode' property */
+  private fun Semver.androidCode(): Int {
+    return major * 1_00_00 + minor * 1_00 + patch
+  }
+
+  /** Write an Android-specific variant of [this] to [stream] */
+  private fun Semver.writeForAndroid(stream: OutputStream) {
+    val newVersionCode = androidCode()
+    val props = Properties()
+    props.setProperty(VERSIONING_PROP_VERSION_CODE, "$newVersionCode")
+    props.setProperty(VERSIONING_PROP_VERSION_NAME, toString())
+    props.store(stream, VERSIONING_PROP_COMMENT)
+  }
+
+  override fun apply(project: Project) {
+    with(project) {
+      val appPlugin =
+        requireNotNull(plugins.findPlugin(AppPlugin::class.java)) {
+          "Plugin 'com.android.application' must be applied to use this plugin"
+        }
+      val propFile = layout.projectDirectory.file(VERSIONING_PROP_FILE)
+      require(propFile.asFile.exists()) {
+        "A 'version.properties' file must exist in the project subdirectory to use this plugin"
+      }
+      val contents = providers.fileContents(propFile).asText.forUseAtConfigurationTime()
+      val versionProps = Properties().also { it.load(contents.get().byteInputStream()) }
+      val versionName =
+        requireNotNull(versionProps.getProperty(VERSIONING_PROP_VERSION_NAME)) {
+          "version.properties must contain a '$VERSIONING_PROP_VERSION_NAME' property"
+        }
+      val versionCode =
+        requireNotNull(versionProps.getProperty(VERSIONING_PROP_VERSION_CODE).toInt()) {
+          "version.properties must contain a '$VERSIONING_PROP_VERSION_CODE' property"
+        }
+      appPlugin.extension.defaultConfig.versionName = versionName
+      appPlugin.extension.defaultConfig.versionCode = versionCode
+      afterEvaluate {
+        val version = Semver(versionName)
+        tasks.register("clearPreRelease") {
+          doLast { version.withClearedSuffix().writeForAndroid(propFile.asFile.outputStream()) }
+        }
+        tasks.register("bumpMajor") {
+          doLast {
+            version
+              .withIncMajor()
+              .withClearedSuffix()
+              .writeForAndroid(propFile.asFile.outputStream())
+          }
+        }
+        tasks.register("bumpMinor") {
+          doLast {
+            version
+              .withIncMinor()
+              .withClearedSuffix()
+              .writeForAndroid(propFile.asFile.outputStream())
+          }
+        }
+        tasks.register("bumpPatch") {
+          doLast {
+            version
+              .withIncPatch()
+              .withClearedSuffix()
+              .writeForAndroid(propFile.asFile.outputStream())
+          }
+        }
+        tasks.register("bumpSnapshot") {
+          doLast {
+            version
+              .withIncMinor()
+              .withSuffix("SNAPSHOT")
+              .writeForAndroid(propFile.asFile.outputStream())
+          }
+        }
+      }
+    }
+  }
+}