Allow specifying the Android NDK API level in the cargo { } block.

This also allows global toolchain directories, which is helpful in
automation; and it makes the toolchain directories include the API
level, which is just good hygiene.

Author: ncalexan

.gitignore

@@ -29,6 +29,7 @@ modules.xml
 .idea/misc.xml
 *.ipr
 /target/
+/samples/rust/target/
 Cargo.lock
 **/*.rs.bk
 .gradle

plugin/build.gradle

@@ -16,7 +16,7 @@ gradlePlugin {
 }
 
 group 'org.mozilla.rust-android-gradle'
-version '0.1.0'
+version '0.2.0'
 
 publishing {
     repositories {
@@ -28,7 +28,6 @@ publishing {
         maven(MavenPublication) {
             groupId 'org.mozilla.rust-android-gradle'
             artifactId 'rust-android'
-            version '0.1.0'
 
             from components.java
         }

plugin/src/main/kotlin/com/nishtahir/CargoBuildTask.kt

@@ -1,5 +1,6 @@
 package com.nishtahir;
 
+import com.android.build.gradle.*
 import org.gradle.api.DefaultTask
 import org.gradle.api.GradleException
 import org.gradle.api.Project
@@ -19,7 +20,12 @@ open class CargoBuildTask : DefaultTask() {
                     throw GradleException("No such target $target")
                 }
 
-                buildProjectForTarget(project, toolchain, this)
+                project.plugins.all {
+                    when (it) {
+                        is AppPlugin -> buildProjectForTarget<AppExtension>(project, toolchain, this)
+                        is LibraryPlugin -> buildProjectForTarget<LibraryExtension>(project, toolchain, this)
+                    }
+                }
 
                 val targetDirectory = targetDirectory ?: "${module}/target"
 
@@ -37,7 +43,10 @@ open class CargoBuildTask : DefaultTask() {
         }
     }
 
-    private fun buildProjectForTarget(project: Project, toolchain: Toolchain, cargoExtension: CargoExtension) {
+    inline fun <reified T : BaseExtension> buildProjectForTarget(project: Project, toolchain: Toolchain, cargoExtension: CargoExtension) {
+        val app = project.extensions[T::class]
+        val apiLevel = cargoExtension.apiLevel ?: app.defaultConfig.minSdkVersion.apiLevel
+
         project.exec { spec ->
             with(spec) {
                 standardOutput = System.out
@@ -55,8 +64,8 @@ open class CargoBuildTask : DefaultTask() {
                 if (toolchain.target != null) {
                     theCommandLine.add("--target=${toolchain.target}")
 
-                    val cc = "${project.getToolchainDirectory()}/${toolchain.cc()}"
-                    val ar = "${project.getToolchainDirectory()}/${toolchain.ar()}"
+                    val cc = "${project.getToolchainDirectory()}/${toolchain.cc(apiLevel)}"
+                    val ar = "${project.getToolchainDirectory()}/${toolchain.ar(apiLevel)}"
                     environment("CC", cc)
                     environment("AR", ar)
                     environment("RUSTFLAGS", "-C linker=$cc")

plugin/src/main/kotlin/com/nishtahir/CargoExtension.kt

@@ -4,6 +4,12 @@ open class CargoExtension {
     var module: String = ""
     var targets: List<String> = emptyList()
 
+    /**
+     * The Android NDK API level to target.  Defaults to the minimum SDK version of the Android
+     * project's default configuration.
+     */
+    var apiLevel: Int? = null
+
     /**
      * The Cargo [release profile](https://doc.rust-lang.org/book/second-edition/ch14-01-release-profiles.html#customizing-builds-with-release-profiles) to build.
      *

plugin/src/main/kotlin/com/nishtahir/Extensions.kt

@@ -9,7 +9,13 @@ const val TOOLS_FOLDER = ".cargo/toolchain"
 
 operator fun <T : Any> ExtensionContainer.get(type: KClass<T>): T = getByType(type.java)
 
-
-
-fun Project.getToolchainDirectory(): File = File(projectDir, TOOLS_FOLDER)
-
+fun Project.getToolchainDirectory(): File {
+    // Share a single toolchain directory, if one is configured, but fall back to per-project
+    // toolchains.
+    val globalDir: String? = System.getenv("ANDROID_NDK_TOOLCHAIN_DIR")
+    if (globalDir != null) {
+        return File(globalDir).absoluteFile
+    } else {
+        return File(projectDir, TOOLS_FOLDER)
+    }
+}

plugin/src/main/kotlin/com/nishtahir/GenerateToolchainsTask.kt

@@ -4,6 +4,7 @@ import java.io.File
 
 import com.android.build.gradle.*
 import org.gradle.api.DefaultTask
+import org.gradle.api.GradleException
 import org.gradle.api.Project
 import org.gradle.api.tasks.TaskAction
 
@@ -21,31 +22,36 @@ open class GenerateToolchainsTask : DefaultTask() {
     }
 
     inline fun <reified T : BaseExtension> congfigureTask(project: Project) {
+        val cargoExtension = project.extensions[CargoExtension::class]
         val app = project.extensions[T::class]
-        val minApi = app.defaultConfig.minSdkVersion.apiLevel
+        val apiLevel = cargoExtension.apiLevel ?: app.defaultConfig.minSdkVersion.apiLevel
         val ndkPath = app.ndkDirectory
 
-        val targets = project.extensions[CargoExtension::class].targets
+        val targets = cargoExtension.targets
 
         toolchains
                 .filter { it.target != null }
-                .filterNot { (arch) -> minApi < 21 && arch.endsWith("64") }
                 .filter { (arch) -> targets.contains(arch) }
                 .forEach { (arch) ->
-                    val dir = File(project.getToolchainDirectory(), arch)
+                     if (arch.endsWith("64") && apiLevel < 21) {
+                        throw GradleException("Can't target 64-bit ${arch} with API level < 21 (${apiLevel})")
+                    }
+
+                    val dir = File(project.getToolchainDirectory(), arch + "-" + apiLevel)
                     if (dir.exists()) {
-                        println("Toolchain for arch ${arch} exists: checked ${dir}")
+                        println("Toolchain for arch ${arch} version ${apiLevel} exists: checked ${dir}")
                         return@forEach
                     }
 
-                    println("Toolchain for arch ${arch} does not exist: checked ${dir}")
+                    println("Toolchain for arch ${arch} version ${apiLevel} does not exist: checked ${dir}")
                     project.exec { spec ->
                         spec.standardOutput = System.out
                         spec.errorOutput = System.out
                         spec.commandLine("$ndkPath/build/tools/make_standalone_toolchain.py")
-                        spec.args("--arch=$arch", "--api=$minApi",
-                                "--install-dir=${project.getToolchainDirectory()}/$arch",
-                                "--force")
+                        spec.args("--arch=$arch",
+                                  "--api=$apiLevel",
+                                  "--install-dir=${dir}",
+                                  "--force")
                     }
                 }
     }

plugin/src/main/kotlin/com/nishtahir/RustAndroidPlugin.kt

@@ -42,8 +42,8 @@ data class Toolchain(val platform: String,
                      val cc: String,
                      val ar: String,
                      val folder: String) {
-    fun cc(): String = "$platform/$cc"
-    fun ar(): String = "$platform/$ar"
+    fun cc(apiLevel: Int): String = "$platform-$apiLevel/$cc"
+    fun ar(apiLevel: Int): String = "$platform-$apiLevel/$ar"
 }
 
 @Suppress("unused")

samples/app/build.gradle

@@ -11,7 +11,7 @@ buildscript {
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:3.1.2'
-        classpath 'org.mozilla.rust-android-gradle:rust-android:0.0.4'
+        classpath 'org.mozilla.rust-android-gradle:rust-android:0.2.0'
     }
 }
 

samples/library/build.gradle

@@ -11,7 +11,7 @@ buildscript {
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:3.1.2'
-        classpath 'org.mozilla.rust-android-gradle:rust-android:0.0.4'
+        classpath 'org.mozilla.rust-android-gradle:rust-android:0.2.0'
     }
 }