SPARK-1338 [scalastyle] Ensure or disallow space after and before token(s).

project/spark-style/src/main/scala/org/apache/spark/scalastyle/SpaceAroundTokenChecker.scala

@@ -0,0 +1,75 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package org.apache.spark.scalastyle
+
+import scalariform.parser.CompilationUnit
+import scalariform.lexer.{TokenType, Token, Tokens}
+import org.scalastyle._
+
+trait SpaceAroundTokenChecker extends ScalariformChecker {
+  val DefaultTokens: String
+  val disallowSpace: Boolean
+  val beforeToken: Boolean
+
+  def verify(ast: CompilationUnit) = {
+    val tokens: Seq[TokenType] = getString("tokens", DefaultTokens).split(",").map(x => TokenType(x.trim))
+    def checkSpaces(left: Token, middle: Token, right: Token) =
+      if (beforeToken) charsBetweenTokens(left, middle) != (if (disallowSpace) 0 else 1)
+      else charsBetweenTokens(middle, right) != (if (disallowSpace) 0 else 1)
+    (for {
+      l@List(left, middle, right) <- ast.tokens.sliding(3)
+      if (l.forall(x => x.tokenType != Tokens.NEWLINE && x.tokenType != Tokens.NEWLINES)
+        && tokens.contains(middle.tokenType)
+        && !middle.associatedWhitespaceAndComments.containsNewline
+        && !right.associatedWhitespaceAndComments.containsNewline
+        && checkSpaces(left, middle, right))
+    } yield {
+      PositionError(middle.offset)
+    }).toList
+  }
+
+}
+
+class EnsureSpaceAfterToken extends SpaceAroundTokenChecker {
+  val errorKey: String = "ensure.single.space.after.token"
+  val DefaultTokens = "COLON, IF"
+  val disallowSpace = false
+  val beforeToken = false
+}
+
+class EnsureSpaceBeforeToken extends SpaceAroundTokenChecker {
+  val errorKey: String = "ensure.single.space.before.token"
+  val DefaultTokens = ""
+  val disallowSpace = false
+  val beforeToken = true
+}
+
+class DisallowSpaceBeforeToken extends SpaceAroundTokenChecker {
+  val errorKey: String = "disallow.space.before.token"
+  val DefaultTokens = "COLON, COMMA, RPAREN"
+  val disallowSpace = true
+  val beforeToken = true
+}
+
+class DisallowSpaceAfterToken extends SpaceAroundTokenChecker {
+  val errorKey: String = "disallow.space.after.token"
+  val DefaultTokens = "LPAREN"
+  val disallowSpace = true
+  val beforeToken = false
+}