Address review feedback

metals/src/main/scala/scala/meta/internal/metals/BloopInstall.scala

@@ -212,16 +212,16 @@ object BloopInstall {
   private class ProcessHandler() extends NuAbstractProcessHandler {
     var response: Option[CompletableFuture[_]] = None
     val completeProcess = Promise[BloopInstallResult]()
-    val stdout = new ProcessOutput(line => scribe.info(line))
-    val stderr = new ProcessOutput(line => scribe.error(line))
+    val stdout = new LineListener(line => scribe.info(line))
+    val stderr = new LineListener(line => scribe.error(line))
 
     override def onStart(nuProcess: NuProcess): Unit = {
       nuProcess.closeStdin(false)
     }
 
     override def onExit(statusCode: Int): Unit = {
-      stdout.onProcessExit()
-      stderr.onProcessExit()
+      stdout.flush()
+      stderr.flush()
       if (!completeProcess.isCompleted) {
         if (statusCode == 0) {
           completeProcess.trySuccess(BloopInstallResult.Installed)
@@ -235,13 +235,13 @@ object BloopInstall {
 
     override def onStdout(buffer: ByteBuffer, closed: Boolean): Unit = {
       if (!closed) {
-        stdout.onByteOutput(buffer)
+        stdout.appendBytes(buffer)
       }
     }
 
     override def onStderr(buffer: ByteBuffer, closed: Boolean): Unit = {
       if (!closed) {
-        stderr.onByteOutput(buffer)
+        stderr.appendBytes(buffer)
       }
     }
   }

metals/src/main/scala/scala/meta/internal/metals/ProcessOutput.scala → metals/src/main/scala/scala/meta/internal/metals/LineListener.scala

@@ -6,31 +6,31 @@ import java.nio.charset.StandardCharsets
 import fansi.ErrorMode
 
 /**
- * Handles streaming console output from a system process with potential ANSI codes.
+ * Converts a stream of strings (with potential ANSI codes and newlines) into a callback for indvidual lines
+ * where each individual line has no newline \n characters.
  *
- * @param onLine The callback handler when the process has printed a single line.
- *               Guaranteed to have no newline \n characters.
+ * @param onLine The callback handler when a single line has been consumed from the input.
  */
-class ProcessOutput(onLine: String => Unit) {
+class LineListener(onLine: String => Unit) {
   private var buffer = new StringBuilder()
 
-  /** The process has exited, clears out buffered output. */
-  def onProcessExit(): Unit = {
+  /** Clear buffered output. */
+  def flush(): Unit = {
     if (buffer.length() > 0) {
       onLine(buffer.toString())
       reset()
     }
   }
 
-  def onByteOutput(bytes: ByteBuffer): this.type = {
-    onPlainOutput(toPlainString(bytes))
+  def appendBytes(bytes: ByteBuffer): this.type = {
+    appendPlainString(toPlainString(bytes))
   }
 
-  def onStringOutput(text: String): this.type = {
-    onPlainOutput(toPlainString(text))
+  def appendString(text: String): this.type = {
+    appendPlainString(toPlainString(text))
   }
 
-  private def onPlainOutput(text: String): this.type = {
+  private def appendPlainString(text: String): this.type = {
     def loop(start: Int): Unit = {
       val newline = text.indexOf('\n', start)
       if (newline < 0) {

tests/unit/src/test/scala/tests/LineListenerSuite.scala

@@ -0,0 +1,63 @@
+package tests
+
+import scala.meta.internal.metals.LineListener
+import scala.collection.mutable
+
+object LineListenerSuite extends BaseSuite {
+  def check(
+      name: String,
+      act: LineListener => Unit,
+      expected: List[String]
+  ): Unit = {
+    test(name) {
+      var buf = mutable.ListBuffer.empty[String]
+      val output = new LineListener(line => buf += line)
+      act(output)
+      output.flush()
+      assertEquals(buf.toList, expected)
+    }
+  }
+
+  check(
+    "flush", { out =>
+      out.appendString("a")
+      out.appendString("b")
+    },
+    List("ab")
+  )
+
+  check(
+    "loop", { out =>
+      out.appendString("a\nb"),
+    },
+    List("a", "b")
+  )
+
+  check(
+    "eol", { out =>
+      out.appendString("a\n")
+    },
+    List("a")
+  )
+
+  check(
+    "eol2", { out =>
+      out.appendString("a\n\n")
+    },
+    List("a", "")
+  )
+
+  check(
+    "ansi", { out =>
+      out.appendString(fansi.Color.Blue("blue").toString()),
+    },
+    List("blue")
+  )
+
+  check(
+    "windows", { out =>
+      out.appendString("a\r\nb")
+    },
+    List("a", "b")
+  )
+}