[K/N] Add clangFormat task for automatic patch formatting ^KT-53776

Merge-request: KT-MR-7880
Merged-by: Alexander Shabalin <Alexander.Shabalin@jetbrains.com>

kotlin-native/build-tools/src/main/kotlin/org/jetbrains/kotlin/ExecLlvm.kt

@@ -12,13 +12,11 @@ import org.gradle.process.ExecOperations
 import org.gradle.process.ExecResult
 import org.gradle.process.ExecSpec
 import org.jetbrains.kotlin.konan.target.PlatformManager
-import org.jetbrains.kotlin.konan.util.DependencyProcessor
 
 fun execLlvmUtility(project: Project, utility: String, action: Action<in ExecSpec>): ExecResult {
-    val llvmBinDirectory = "${project.platformManager.hostPlatform.absoluteLlvmHome}/bin"
     return project.exec(Action<ExecSpec> {
         action.execute(this)
-        executable = "$llvmBinDirectory/$utility"
+        executable = project.platformManager.resolveLlvmUtility(utility)
     })
 }
 
@@ -26,10 +24,11 @@ fun execLlvmUtility(project: Project, utility: String, closure: Closure<in ExecS
     return execLlvmUtility(project, utility) { project.configure(this, closure) }
 }
 
+fun PlatformManager.resolveLlvmUtility(utility: String) = "${hostPlatform.absoluteLlvmHome}/bin/$utility"
+
 fun ExecOperations.execLlvmUtility(platformManager: PlatformManager, utility: String, action: Action<in ExecSpec>): ExecResult {
-    val llvmBinDirectory = "${platformManager.hostPlatform.absoluteLlvmHome}/bin"
     return exec {
         action.execute(this)
-        executable = "$llvmBinDirectory/$utility"
+        executable = platformManager.resolveLlvmUtility(utility)
     }
 }

kotlin-native/build-tools/src/main/kotlin/org/jetbrains/kotlin/bitcode/CompileToBitcodePlugin.kt

@@ -16,10 +16,7 @@ import org.gradle.api.services.BuildServiceParameters
 import org.gradle.kotlin.dsl.*
 import org.gradle.language.base.plugins.LifecycleBasePlugin
 import org.jetbrains.kotlin.ExecClang
-import org.jetbrains.kotlin.cpp.CompilationDatabaseExtension
-import org.jetbrains.kotlin.cpp.CompilationDatabasePlugin
-import org.jetbrains.kotlin.cpp.CompileToExecutable
-import org.jetbrains.kotlin.cpp.RunGTest
+import org.jetbrains.kotlin.cpp.*
 import org.jetbrains.kotlin.konan.target.KonanTarget
 import org.jetbrains.kotlin.konan.target.PlatformManager
 import org.jetbrains.kotlin.konan.target.SanitizerKind
@@ -68,6 +65,7 @@ private abstract class CompileTestsSemaphore : BuildService<BuildServiceParamete
 open class CompileToBitcodePlugin : Plugin<Project> {
     override fun apply(target: Project) {
         target.apply<CompilationDatabasePlugin>()
+        target.apply<GitClangFormatPlugin>()
         target.extensions.create<CompileToBitcodeExtension>(EXTENSION_NAME, target)
     }
 

kotlin-native/build-tools/src/main/kotlin/org/jetbrains/kotlin/cpp/GitClangFormat.kt

@@ -0,0 +1,84 @@
+/*
+ * Copyright 2010-2022 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.cpp
+
+import org.gradle.api.DefaultTask
+import org.gradle.api.provider.Property
+import org.gradle.api.tasks.Input
+import org.gradle.api.tasks.TaskAction
+import org.gradle.api.tasks.UntrackedTask
+import org.gradle.api.tasks.options.Option
+import org.gradle.kotlin.dsl.getByType
+import org.gradle.process.ExecOperations
+import org.jetbrains.kotlin.konan.target.PlatformManager
+import org.jetbrains.kotlin.resolveLlvmUtility
+import java.io.ByteArrayOutputStream
+import javax.inject.Inject
+
+/**
+ * A task that formats changed code with clang-format.
+ *
+ * Will run <git-clang-format> --binary <clang-format> --force $(git merge-base [parent] HEAD) [directory]
+ */
+@UntrackedTask(because = "Formatter should always run when asked")
+abstract class GitClangFormat : DefaultTask() {
+    private val platformManager = project.extensions.getByType<PlatformManager>()
+
+    /**
+     * Parent branch for the current branch.
+     */
+    @get:Option(option = "parent", description = "base parent of the branch; by default origin/master")
+    @get:Input
+    abstract val parent: Property<String>
+
+    /**
+     * Directory in which to format sources.
+     */
+    @get:Option(option = "directory", description = "directory in which to format sources; by default project's source directory")
+    @get:Input
+    abstract val directory: Property<String>
+
+    /**
+     * Whether to run the tool in interactive mode.
+     */
+    @get:Option(option = "interactive", description = "interactively ask about each change before applying; by default false")
+    @get:Input
+    abstract val interactive: Property<Boolean>
+
+    @get:Inject
+    protected abstract val execOperations: ExecOperations
+
+    @TaskAction
+    fun run() {
+        val gitClangFormat = platformManager.resolveLlvmUtility("git-clang-format")
+        val clangFormat = platformManager.resolveLlvmUtility("clang-format")
+        val parent = this.parent.get()
+        val directory = this.directory.get()
+        val interactive = this.interactive.get()
+
+        val commit = ByteArrayOutputStream().let {
+            execOperations.exec {
+                executable = "git"
+                args("merge-base", parent, "HEAD")
+                standardOutput = it
+            }
+            it.toString().trim()
+        }
+        execOperations.exec {
+            executable = gitClangFormat
+            args("--binary", clangFormat)
+            args("--force")
+            if (interactive) {
+                args("--patch")
+                // Not a nice experience, but it works.
+                standardInput = System.`in`
+            }
+            args(commit)
+            args("--")
+            args(directory)
+        }
+    }
+}

kotlin-native/build-tools/src/main/kotlin/org/jetbrains/kotlin/cpp/GitClangFormatPlugin.kt

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2010-2022 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.cpp
+
+import org.gradle.api.Plugin
+import org.gradle.api.Project
+import org.gradle.kotlin.dsl.*
+
+/**
+ * Plugin for [GitClangFormat] that creates a task `clangFormat` that will format project sources in the current branch.
+ */
+open class GitClangFormatPlugin : Plugin<Project> {
+    override fun apply(target: Project) {
+        val directory = target.layout.projectDirectory.toString()
+        target.tasks.register<GitClangFormat>("clangFormat") {
+            description = "Run clang-format in $directory"
+            group = TASK_GROUP
+            parent.convention("origin/master")
+            this.directory.convention(directory)
+            interactive.convention(false)
+            // Needs LLVM toolchain.
+            // TODO: It does not need every dependency ever, only LLVM toolchain for the host.
+            dependsOn(":kotlin-native:dependencies:update")
+        }
+    }
+
+    companion object {
+        @JvmStatic
+        val TASK_GROUP = "development support"
+    }
+}