Add automatic Android NDK provisioning

README.md

@@ -66,6 +66,9 @@ class Main {
 - aarch64-linux
 - aarch64-linux-android
 
+# Android native builds
+Android native builds use the Android NDK compiler. If `ANDROID_NDK_HOME`, `ANDROID_NDK_ROOT`, `ANDROID_HOME`, or `ANDROID_SDK_ROOT` points to an installed NDK, the build uses it. Otherwise, Gradle downloads the NDK version configured by `androidNdkVersion` in `gradle.properties` into the root `build/android-ndk` directory.
+
 # Developers: How to Add a Parser
 
 To add a new language parser to this project, we provide a code generation task that handles most of the boilerplate. This is also how you can add an "unofficial" or community parser.

build.gradle

@@ -114,6 +114,9 @@ subprojects {
     tasks.register('buildNative', BuildNativeTask) {
         zigExe = rootProject.downloadZig.zigExe
         dependsOn downloadSource, rootProject.downloadZig
+        if (((String) rootProject.properties.get("treeSitterTargets")).contains("android")) {
+            dependsOn rootProject.downloadAndroidNdk
+        }
     }
 
     tasks.withType(Javadoc) {
@@ -139,6 +142,8 @@ tasks.register('downloadZig', DownloadZigTask){
     dependsOn downloadMiniSign
 }
 
+tasks.register('downloadAndroidNdk', DownloadAndroidNdkTask)
+
 tasks.register("gen", GenTask) {
     group = "build setup"
     description = "Generate sub project for tree sitter parser"
@@ -251,4 +256,4 @@ tasks.register("postPublish") {
         }
         println "Published to Portal with response body:\n${resp.body()}"
     }
-}
+}

buildSrc/src/main/groovy/BuildNativeTask.groovy

@@ -195,13 +195,17 @@ class BuildNativeTask extends DefaultTask{
         }
 
         def ndkDir = findAndroidNdkDir()
-        def hostTag = System.getProperty("os.name").toLowerCase(Locale.ROOT).contains("mac")
-                ? "darwin-x86_64"
-                : "linux-x86_64"
+        def osName = System.getProperty("os.name").toLowerCase(Locale.ROOT)
+        def hostTag = osName.contains("win")
+                ? "windows-x86_64"
+                : osName.contains("mac")
+                    ? "darwin-x86_64"
+                    : "linux-x86_64"
         def apiLevel = project.findProperty("androidApiLevel") ?: "21"
+        def compilerName = "aarch64-linux-android${apiLevel}-clang${osName.contains("win") ? ".cmd" : ""}"
         def compiler = new File(
                 ndkDir,
-                "toolchains/llvm/prebuilt/${hostTag}/bin/aarch64-linux-android${apiLevel}-clang"
+                "toolchains/llvm/prebuilt/${hostTag}/bin/${compilerName}"
         )
         if (!compiler.exists()) {
             throw new GradleException("Android compiler not found: ${compiler}. Set ANDROID_NDK_HOME or ANDROID_NDK_ROOT.")
@@ -224,7 +228,13 @@ class BuildNativeTask extends DefaultTask{
             }
         }
 
-        throw new GradleException("Android NDK not found. Set ANDROID_NDK_HOME, ANDROID_NDK_ROOT, ANDROID_HOME, or ANDROID_SDK_ROOT.")
+        def downloadAndroidNdkTask = project.rootProject.tasks.named("downloadAndroidNdk").get()
+        def downloadedNdk = downloadAndroidNdkTask.androidNdkHome.asFile
+        if (downloadedNdk.exists()) {
+            return downloadedNdk
+        }
+
+        throw new GradleException("Android NDK not found. Set ANDROID_NDK_HOME, ANDROID_NDK_ROOT, ANDROID_HOME, or ANDROID_SDK_ROOT, or run the downloadAndroidNdk task.")
     }
 
     private void removeWindowsDebugFiles(){

buildSrc/src/main/groovy/DownloadAndroidNdkTask.groovy

@@ -0,0 +1,117 @@
+import org.gradle.api.DefaultTask
+import org.gradle.api.GradleException
+import org.gradle.api.file.Directory
+import org.gradle.api.file.RegularFile
+import org.gradle.api.tasks.Input
+import org.gradle.api.tasks.Internal
+import org.gradle.api.tasks.OutputDirectory
+import org.gradle.api.tasks.OutputFile
+import org.gradle.api.tasks.TaskAction
+import org.gradle.nativeplatform.platform.internal.DefaultNativePlatform
+import org.gradle.nativeplatform.platform.internal.DefaultOperatingSystem
+import org.treesitter.build.Utils
+
+class DownloadAndroidNdkTask extends DefaultTask {
+
+    @Internal
+    DefaultOperatingSystem os
+
+    DownloadAndroidNdkTask() {
+        group = "download"
+        description = "Download Android NDK required for Android native targets"
+        os = DefaultNativePlatform.currentOperatingSystem
+    }
+
+    @Input
+    String getAndroidNdkVersion() {
+        return project.rootProject.property("androidNdkVersion")
+    }
+
+    @Internal
+    Directory getAndroidNdkDir() {
+        return project.rootProject.layout.buildDirectory.dir("android-ndk").get()
+    }
+
+    @OutputDirectory
+    Directory getAndroidNdkHome() {
+        return androidNdkDir.dir("android-ndk-${androidNdkVersion}")
+    }
+
+    @Internal
+    String getOsName() {
+        if (os.windows) {
+            return "windows"
+        } else if (os.macOsX) {
+            return "darwin"
+        } else if (os.linux) {
+            return "linux"
+        } else {
+            throw new GradleException("Unsupported OS: " + os.name)
+        }
+    }
+
+    @OutputFile
+    RegularFile getAndroidNdkArchive() {
+        return androidNdkDir.file("android-ndk-${androidNdkVersion}-${osName}.zip")
+    }
+
+    @Internal
+    String getAndroidNdkUrl() {
+        return "https://dl.google.com/android/repository/${androidNdkArchive.asFile.name}"
+    }
+
+    @TaskAction
+    void downloadAndroidNdk() {
+        def installedNdk = findInstalledAndroidNdkDir()
+        if (installedNdk != null) {
+            logger.lifecycle("Using installed Android NDK: {}", installedNdk)
+            return
+        }
+
+        if (androidNdkHome.asFile.exists()) {
+            logger.lifecycle("Using downloaded Android NDK: {}", androidNdkHome.asFile)
+            return
+        }
+
+        logger.lifecycle("Downloading Android NDK from {}", androidNdkUrl)
+        Utils.downloadFile(androidNdkUrl, androidNdkArchive.asFile)
+        Utils.unzipArchive(androidNdkArchive.asFile, androidNdkDir.asFile)
+        androidCompiler.asFile.setExecutable(true, true)
+    }
+
+    @Internal
+    RegularFile getAndroidCompiler() {
+        return androidNdkHome.file("toolchains/llvm/prebuilt/${hostTag}/bin/aarch64-linux-android21-clang${os.windows ? '.cmd' : ''}")
+    }
+
+    @Internal
+    String getHostTag() {
+        if (os.windows) {
+            return "windows-x86_64"
+        } else if (os.macOsX) {
+            return "darwin-x86_64"
+        } else if (os.linux) {
+            return "linux-x86_64"
+        } else {
+            throw new GradleException("Unsupported OS: " + os.name)
+        }
+    }
+
+    File findInstalledAndroidNdkDir() {
+        def envNdk = System.getenv("ANDROID_NDK_HOME") ?: System.getenv("ANDROID_NDK_ROOT")
+        if (envNdk) {
+            return new File(envNdk)
+        }
+
+        def sdkDir = System.getenv("ANDROID_HOME") ?: System.getenv("ANDROID_SDK_ROOT")
+        if (sdkDir) {
+            def ndkRoot = new File(sdkDir, "ndk")
+            def ndks = ndkRoot.listFiles()?.findAll { it.isDirectory() }?.sort { a, b -> b.name <=> a.name }
+            if (ndks) {
+                return ndks.first()
+            }
+        }
+
+        return null
+    }
+}

gradle.properties

@@ -3,6 +3,7 @@ miniSigDir=minisign
 zigDir=zig
 zigVersion=0.11.0
 miniSignVersion=0.11
+androidNdkVersion=r27c
 zigPubKey=RWSGOq2NVecA2UPNdBUZykf1CCb147pkmdtYxgb3Ti+JO/wCYvhbAb/U
 treeSitterTargets=x86_64-windows,x86_64-macos,x86_64-linux-gnu,aarch64-linux-gnu,aarch64-macos,aarch64-linux-android
 org.gradle.parallel=true