gh-pages only cleans up target

The pages CopySpec defaults to targeting the root of the repo,
but in cases like documentation, you may want to target a subfolder
such as one using the version in the name. This can already be done
with the into method on the CopySpec. With this change the into
setting of the pages CopySpec is also what controls which directory
is cleaned up before the copy. This allows multiple versions of doc
to exist in the repo without having the be kept in source or generated
each time. This fixes #94.

src/main/groovy/org/ajoberstar/gradle/git/ghpages/GithubPagesPlugin.groovy

@@ -53,7 +53,7 @@ class GithubPagesPlugin implements Plugin<Project> {
 		Task task = project.tasks.create(PREPARE_TASK_NAME, Copy)
 		task.with {
 			description = 'Prepare the gh-pages changes locally'
-			with extension.pages
+			with extension.pages.realSpec
 			into { extension.workingDir }
 			doFirst {
 				extension.workingDir.deleteDir()
@@ -71,7 +71,8 @@ class GithubPagesPlugin implements Plugin<Project> {
 					extension.deleteExistingFiles = true
 				}
 
-				def filesList = extension.workingDir.list({ dir, name ->
+				def targetDir = project.file("${extension.workingDir}/${extension.pages.relativeDestinationDir}")
+				def filesList = targetDir.list({ dir, name ->
 					return !name.equals('.git')
 				})
 				if (filesList && extension.deleteExistingFiles) {

src/main/groovy/org/ajoberstar/gradle/git/ghpages/GithubPagesPluginExtension.groovy

@@ -15,6 +15,8 @@
  */
 package org.ajoberstar.gradle.git.ghpages
 
+import groovy.transform.PackageScope
+
 import org.ajoberstar.grgit.Grgit
 import org.ajoberstar.grgit.exception.GrgitException
 
@@ -76,10 +78,9 @@ class GithubPagesPluginExtension implements AuthenticationSupported {
 	 * the extension for
 	 */
 	GithubPagesPluginExtension(Project project) {
-		this.project = project;
-		this.pages = project.copySpec {
-			from 'src/main/ghpages'
-		}
+		this.project = project
+		this.pages = new DestinationCopySpec(project)
+		pages.from 'src/main/ghpages'
 
 		// defaulting the repoUri to the project repo's origin
 		try {
@@ -126,4 +127,28 @@ class GithubPagesPluginExtension implements AuthenticationSupported {
 	void credentials(Closure closure) {
 		ConfigureUtil.configure(closure, credentials)
 	}
+
+	static class DestinationCopySpec implements CopySpec {
+		private Project project
+		private Object destPath
+
+		@Delegate
+		CopySpec realSpec
+
+		public DestinationCopySpec(Project project) {
+			this.project = project
+			this.realSpec = project.copySpec {}
+		}
+
+		public File getRelativeDestinationDir() {
+			return destPath ? project.file(destPath) : new File('.')
+		}
+
+		@Override
+		public CopySpec into(Object destPath) {
+			this.destPath = destPath
+			realSpec.into(destPath)
+			return this
+		}
+	}
 }