Add `installGitHooks` task for pre-push Git hooks (#1516)

* build: add a pre-push task and Gradle task to install it

* Document `installGitHooks` in contributing.md

2 files changed, 50 insertions, 0 deletions

diff --git a/buildSrc/src/main/java/BaseProjectConfig.kt b/buildSrc/src/main/java/BaseProjectConfig.kt
index 06648ae0..2c6f8fdc 100644
--- a/buildSrc/src/main/java/BaseProjectConfig.kt
+++ b/buildSrc/src/main/java/BaseProjectConfig.kt
@@ -11,6 +11,7 @@ import org.gradle.api.tasks.testing.Test
 import org.gradle.api.tasks.testing.logging.TestLogEvent
 import org.gradle.api.tasks.wrapper.Wrapper
 import org.gradle.kotlin.dsl.maven
+import org.gradle.kotlin.dsl.register
 import org.gradle.kotlin.dsl.repositories
 import org.gradle.kotlin.dsl.withType
 import org.gradle.language.nativeplatform.internal.BuildType
@@ -26,6 +27,11 @@ internal fun Project.configureForRootProject() {
     distributionSha256Sum = "f581709a9c35e9cb92e16f585d2c4bc99b2b1a5f85d2badbd3dc6bff59e1e6dd"
   }
   configureBinaryCompatibilityValidator()
+  tasks.register<GitHooks>("installGitHooks") {
+    val projectDirectory = layout.projectDirectory
+    hookScript.set(projectDirectory.file("scripts/pre-push-hook.sh").asFile.readText())
+    hookOutput.set(projectDirectory.file(".git/hooks/pre-push").asFile)
+  }
 }
 
 /** Configure all projects including the root project */
diff --git a/buildSrc/src/main/java/GitHooks.kt b/buildSrc/src/main/java/GitHooks.kt
new file mode 100644
index 00000000..c7e9066f
--- /dev/null
+++ b/buildSrc/src/main/java/GitHooks.kt
@@ -0,0 +1,44 @@
+/*
+ * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+import java.io.File
+import java.nio.file.Files
+import java.nio.file.attribute.PosixFilePermission.GROUP_EXECUTE
+import java.nio.file.attribute.PosixFilePermission.GROUP_READ
+import java.nio.file.attribute.PosixFilePermission.OTHERS_EXECUTE
+import java.nio.file.attribute.PosixFilePermission.OTHERS_READ
+import java.nio.file.attribute.PosixFilePermission.OWNER_EXECUTE
+import java.nio.file.attribute.PosixFilePermission.OWNER_READ
+import java.nio.file.attribute.PosixFilePermission.OWNER_WRITE
+import org.gradle.api.DefaultTask
+import org.gradle.api.provider.Property
+import org.gradle.api.tasks.CacheableTask
+import org.gradle.api.tasks.Input
+import org.gradle.api.tasks.OutputFile
+import org.gradle.api.tasks.TaskAction
+
+@CacheableTask
+abstract class GitHooks : DefaultTask() {
+  @get:Input abstract val hookScript: Property<String>
+
+  @get:OutputFile abstract val hookOutput: Property<File>
+
+  @TaskAction
+  fun install() {
+    hookOutput.get().writeText(hookScript.get())
+    Files.setPosixFilePermissions(
+      hookOutput.get().toPath(),
+      setOf(
+        OWNER_READ,
+        OWNER_WRITE,
+        OWNER_EXECUTE,
+        GROUP_READ,
+        GROUP_EXECUTE,
+        OTHERS_READ,
+        OTHERS_EXECUTE,
+      )
+    )
+  }
+}