1 files changed, 105 insertions, 0 deletions
diff --git a/plugins/uber-jar/src/uberjar/JarUtils.scala b/plugins/uber-jar/src/uberjar/JarUtils.scala
new file mode 100644
index 0000000..f73947e
--- /dev/null
+++ b/plugins/uber-jar/src/uberjar/JarUtils.scala
@@ -0,0 +1,105 @@
+package cbt.uberjar
+
+import java.io.File
+import java.nio.file._
+import java.nio.file.attribute.BasicFileAttributes
+import java.util.jar.{JarFile, JarOutputStream}
+import java.util.zip.{ZipEntry, ZipException}
+
+private[cbt] trait JarUtils {
+
+  protected val (pathSeparator, jarFileMatcher, excludeFileMatcher) = {
+    val fs = FileSystems.getDefault
+    (fs.getSeparator, fs.getPathMatcher("glob:**.jar"), fs.getPathMatcher("glob:**{.RSA,.DSA,.SF,.MF}"))
+  }
+
+  /**
+    * If `root` is directory: writes content of directory to jar with original mapping
+    * If `root` is file: writes this file to jar
+    * @param root parent directory, with content should go to jar, or file to be written
+    * @param out jar output stream
+    * @param log logger
+    * @return returns `root`
+    */
+  protected def writeFilesToJar(root: Path, out: JarOutputStream)(log: String => Unit): Path = {
+    Files.walkFileTree(root, new SimpleFileVisitor[Path]() {
+      override def visitFile(file: Path, attrs: BasicFileAttributes): FileVisitResult = {
+        // when we put part of compiled classes, zip already contains some entries. We should not duplicate them.
+        try {
+          out.putNextEntry(new ZipEntry(root.relativize(file).toString))
+          Files.copy(file, out)
+          out.closeEntry()
+        } catch {
+          case e: ZipException => log(s"Failed to add entry, skipping cause: $e")
+        }
+        FileVisitResult.CONTINUE
+      }
+
+      override def preVisitDirectory(dir: Path, attrs: BasicFileAttributes): FileVisitResult = {
+        // when we put part compiled classes, zip already contains some entries. We should not duplicate them.
+        try {
+          out.putNextEntry(new ZipEntry(root.relativize(dir).toString + pathSeparator))
+          out.closeEntry()
+        } catch {
+          case e: ZipException => log(s"Failed to add entry, skipping cause: $e")
+        }
+        FileVisitResult.CONTINUE
+      }
+    })
+  }
+
+  /**
+    * Extracts jars, and writes them on disk. Returns root directory of extracted jars
+    * TODO: in future we probably should save extracted jars in target directory, to reuse them on second run
+    * @param jars list of *.jar files
+    * @param log logger
+    * @return root directory of extracted jars
+    */
+  protected def extractJars(jars: Seq[File])(log: String => Unit): Path = {
+    val destDir = {
+      val path = Files.createTempDirectory("unjars")
+      path.toFile.deleteOnExit()
+      log(s"Unjars directory: $path")
+      path
+    }
+    jars foreach { jar => extractJar(jar, destDir)(log) }
+    destDir
+  }
+
+  /**
+    * Extracts content of single jar file to destination directory.
+    * When extracting jar, if same file already exists, we skip(don't write) this file.
+    * TODO: maybe skipping duplicates is not best strategy. Figure out duplicate strategy.
+    * @param jarFile jar file to extract
+    * @param destDir destination directory
+    * @param log logger
+    */
+  private def extractJar(jarFile: File, destDir: Path)(log: String => Unit): Unit = {
+    log(s"Extracting jar: $jarFile")
+    val jar = new JarFile(jarFile)
+    val enumEntries = jar.entries
+    while (enumEntries.hasMoreElements) {
+      val entry = enumEntries.nextElement()
+      //        log(s"Entry name: ${entry.getName}")
+      val entryPath = destDir.resolve(entry.getName)
+      if (excludeFileMatcher.matches(entryPath)) {
+        log(s"Excluded file ${entryPath.getFileName} from jar: $jarFile")
+      } else {
+        if (Files.exists(entryPath)) {
+          log(s"File $entryPath already exists, skipping.")
+        } else {
+          if (entry.isDirectory) {
+            Files.createDirectory(entryPath)
+            //              log(s"Created directory: $entryPath")
+          } else {
+            val is = jar.getInputStream(entry)
+            Files.copy(is, entryPath)
+            is.close()
+            //              log(s"Wrote file: $entryPath")
+          }
+        }
+      }
+    }
+  }
+
+}