Combine all sources into a sub-directory

sources/src/gradlew.ts

@@ -0,0 +1,42 @@
+import * as path from 'path'
+import fs from 'fs'
+
+const IS_WINDOWS = process.platform === 'win32'
+
+export function wrapperScriptFilename(): string {
+    return IS_WINDOWS ? './gradlew.bat' : './gradlew'
+}
+
+export function installScriptFilename(): string {
+    return IS_WINDOWS ? 'gradle.bat' : 'gradle'
+}
+
+export function gradleWrapperScript(buildRootDirectory: string): string {
+    validateGradleWrapper(buildRootDirectory)
+    return wrapperScriptFilename()
+}
+
+function validateGradleWrapper(buildRootDirectory: string): void {
+    const wrapperScript = path.resolve(buildRootDirectory, wrapperScriptFilename())
+    verifyExists(wrapperScript, 'Gradle Wrapper script')
+    verifyIsExecutableScript(wrapperScript)
+
+    const wrapperProperties = path.resolve(buildRootDirectory, 'gradle/wrapper/gradle-wrapper.properties')
+    verifyExists(wrapperProperties, 'Gradle wrapper properties file')
+}
+
+function verifyExists(file: string, description: string): void {
+    if (!fs.existsSync(file)) {
+        throw new Error(
+            `Cannot locate ${description} at '${file}'. Specify 'gradle-version' for projects without Gradle wrapper configured.`
+        )
+    }
+}
+
+function verifyIsExecutableScript(toExecute: string): void {
+    try {
+        fs.accessSync(toExecute, fs.constants.X_OK)
+    } catch (err) {
+        throw new Error(`Gradle script '${toExecute}' is not executable.`)
+    }
+}