Eliminated separate RangePositions trait.

One of those eternal headaches which probably sounded better
on paper. Even before range positions are the default, there's
no reason we can't have the range position code available
in all globals enabled via settings, just like everything else.

1 files changed, 258 insertions, 8 deletions

diff --git a/src/reflect/scala/reflect/internal/Positions.scala b/src/reflect/scala/reflect/internal/Positions.scala
index 69f6d22538..f5aeec63e1 100644
--- a/src/reflect/scala/reflect/internal/Positions.scala
+++ b/src/reflect/scala/reflect/internal/Positions.scala
@@ -2,27 +2,59 @@ package scala.reflect
 package internal
 
 import util._
+import scala.collection.mutable.ListBuffer
 
+/** Handling range positions
+ *  atPos, the main method in this trait, will add positions to a tree,
+ *  and will ensure the following properties:
+ *
+ *    1. All nodes between the root of the tree and nodes that already have positions
+ *       will be assigned positions.
+ *    2. No node which already has a position will be assigned a different range; however
+ *       a RangePosition might become a TransparentPosition.
+ *    3. The position of each assigned node includes the positions of each of its children.
+ *    4. The positions of all solid descendants of children of an assigned node
+ *       are mutually non-overlapping.
+ *
+ * Here, the solid descendant of a node are:
+ *
+ *   If the node has a TransparentPosition, the solid descendants of all its children
+ *   Otherwise, the singleton consisting of the node itself.
+ */
 trait Positions extends api.Positions { self: SymbolTable =>
 
   type Position = scala.reflect.internal.util.Position
   val NoPosition = scala.reflect.internal.util.NoPosition
   implicit val PositionTag = ClassTag[Position](classOf[Position])
 
+  def inform(msg: String): Unit
+
+  def useOffsetPositions: Boolean = true
+
   /** A position that wraps a set of trees.
    *  The point of the wrapping position is the point of the default position.
    *  If some of the trees are ranges, returns a range position enclosing all ranges
    *  Otherwise returns default position that is either focused or not.
    */
   def wrappingPos(default: Position, trees: List[Tree]): Position = wrappingPos(default, trees, true)
-  def wrappingPos(default: Position, trees: List[Tree], focus: Boolean): Position = default
+  def wrappingPos(default: Position, trees: List[Tree], focus: Boolean): Position = {
+    if (useOffsetPositions) default else {
+      val ranged = trees filter (_.pos.isRange)
+      if (ranged.isEmpty) if (focus) default.focus else default
+      else new RangePosition(default.source, (ranged map (_.pos.start)).min, default.point, (ranged map (_.pos.end)).max)
+    }
+  }
 
   /** A position that wraps the non-empty set of trees.
    *  The point of the wrapping position is the point of the first trees' position.
    *  If some of the trees are non-synthetic, returns a range position enclosing the non-synthetic trees
    *  Otherwise returns a synthetic offset position to point.
    */
-  def wrappingPos(trees: List[Tree]): Position = trees.head.pos
+  def wrappingPos(trees: List[Tree]): Position = {
+    val headpos = trees.head.pos
+    if (useOffsetPositions || !headpos.isDefined) headpos
+    else wrappingPos(headpos, trees)
+  }
 
   /** Ensure that given tree has no positions that overlap with
    *  any of the positions of `others`. This is done by
@@ -30,10 +62,212 @@ trait Positions extends api.Positions { self: SymbolTable =>
    *  to some of the nodes in `tree` or focusing on the position.
    */
   def ensureNonOverlapping(tree: Tree, others: List[Tree]){ ensureNonOverlapping(tree, others, true) }
-  def ensureNonOverlapping(tree: Tree, others: List[Tree], focus: Boolean) {}
+  def ensureNonOverlapping(tree: Tree, others: List[Tree], focus: Boolean) {
+    if (useOffsetPositions) return
+
+    def isOverlapping(pos: Position) =
+      pos.isRange && (others exists (pos overlaps _.pos))
+
+    if (isOverlapping(tree.pos)) {
+      val children = tree.children
+      children foreach (ensureNonOverlapping(_, others, focus))
+      if (tree.pos.isOpaqueRange) {
+        val wpos = wrappingPos(tree.pos, children, focus)
+        tree setPos (if (isOverlapping(wpos)) tree.pos.makeTransparent else wpos)
+      }
+    }
+  }
+
+  def rangePos(source: SourceFile, start: Int, point: Int, end: Int): Position =
+    if (useOffsetPositions) new OffsetPosition(source, point)
+    else new RangePosition(source, start, point, end)
+
+  def validatePositions(tree: Tree) {
+    if (useOffsetPositions) return
+
+    def reportTree(prefix : String, tree : Tree) {
+      val source = if (tree.pos.isDefined) tree.pos.source else ""
+      inform("== "+prefix+" tree ["+tree.id+"] of type "+tree.productPrefix+" at "+tree.pos.show+source)
+      inform("")
+      inform(treeStatus(tree))
+      inform("")
+    }
+
+    def positionError(msg: String)(body : => Unit) {
+      inform("======= Position error\n" + msg)
+      body
+      inform("\nWhile validating #" + tree.id)
+      inform(treeStatus(tree))
+      inform("\nChildren:")
+      tree.children map (t => "  " + treeStatus(t, tree)) foreach inform
+      inform("=======")
+      throw new ValidateException(msg)
+    }
+
+    def validate(tree: Tree, encltree: Tree): Unit = {
+
+      if (!tree.isEmpty && tree.canHaveAttrs) {
+        if (settings.Yposdebug.value && (settings.verbose.value || settings.Yrangepos.value))
+          println("[%10s] %s".format("validate", treeStatus(tree, encltree)))
+
+        if (!tree.pos.isDefined)
+          positionError("Unpositioned tree #"+tree.id) {
+            inform("%15s %s".format("unpositioned", treeStatus(tree, encltree)))
+            inform("%15s %s".format("enclosing", treeStatus(encltree)))
+            encltree.children foreach (t => inform("%15s %s".format("sibling", treeStatus(t, encltree))))
+          }
+        if (tree.pos.isRange) {
+          if (!encltree.pos.isRange)
+            positionError("Synthetic tree ["+encltree.id+"] contains nonsynthetic tree ["+tree.id+"]") {
+            reportTree("Enclosing", encltree)
+            reportTree("Enclosed", tree)
+            }
+          if (!(encltree.pos includes tree.pos))
+            positionError("Enclosing tree ["+encltree.id+"] does not include tree ["+tree.id+"]") {
+              reportTree("Enclosing", encltree)
+              reportTree("Enclosed", tree)
+            }
+
+          findOverlapping(tree.children flatMap solidDescendants) match {
+            case List() => ;
+            case xs => {
+              positionError("Overlapping trees "+xs.map { case (x, y) => (x.id, y.id) }.mkString("", ", ", "")) {
+                reportTree("Ancestor", tree)
+                for((x, y) <- xs) {
+                  reportTree("First overlapping", x)
+                  reportTree("Second overlapping", y)
+                }
+              }
+            }
+          }
+        }
+        for (ct <- tree.children flatMap solidDescendants) validate(ct, tree)
+      }
+    }
+
+    if (!isPastTyper)
+      validate(tree, tree)
+  }
+
+  def solidDescendants(tree: Tree): List[Tree] =
+    if (tree.pos.isTransparent) tree.children flatMap solidDescendants
+    else List(tree)
+
+  /** A free range from `lo` to `hi` */
+  private def free(lo: Int, hi: Int): Range =
+    Range(new RangePosition(null, lo, lo, hi), EmptyTree)
+
+  /** The maximal free range */
+  private lazy val maxFree: Range = free(0, Int.MaxValue)
+
+  /** A singleton list of a non-empty range from `lo` to `hi`, or else the empty List */
+  private def maybeFree(lo: Int, hi: Int) =
+    if (lo < hi) List(free(lo, hi))
+    else List()
+
+  /** Insert `pos` into ranges `rs` if possible;
+   *  otherwise add conflicting trees to `conflicting`.
+   */
+  private def insert(rs: List[Range], t: Tree, conflicting: ListBuffer[Tree]): List[Range] = rs match {
+    case List() =>
+      assert(conflicting.nonEmpty)
+      rs
+    case r :: rs1 =>
+      assert(!t.pos.isTransparent)
+      if (r.isFree && (r.pos includes t.pos)) {
+//      println("subdividing "+r+"/"+t.pos)
+        maybeFree(t.pos.end, r.pos.end) ::: List(Range(t.pos, t)) ::: maybeFree(r.pos.start, t.pos.start) ::: rs1
+      } else {
+        if (!r.isFree && (r.pos overlaps t.pos)) conflicting += r.tree
+        r :: insert(rs1, t, conflicting)
+      }
+  }
+
+  /** Replace elem `t` of `ts` by `replacement` list. */
+  private def replace(ts: List[Tree], t: Tree, replacement: List[Tree]): List[Tree] =
+    if (ts.head == t) replacement ::: ts.tail
+    else ts.head :: replace(ts.tail, t, replacement)
+
+  /** Does given list of trees have mutually non-overlapping positions?
+   *  pre: None of the trees is transparent
+   */
+  def findOverlapping(cts: List[Tree]): List[(Tree, Tree)] = {
+    var ranges = List(maxFree)
+    for (ct <- cts) {
+      if (ct.pos.isOpaqueRange) {
+        val conflicting = new ListBuffer[Tree]
+        ranges = insert(ranges, ct, conflicting)
+        if (conflicting.nonEmpty) return conflicting.toList map (t => (t, ct))
+      }
+    }
+    List()
+  }
+
+  /** Set position of all children of a node
+   *  @param  pos   A target position.
+   *                Uses the point of the position as the point of all positions it assigns.
+   *                Uses the start of this position as an Offset position for unpositioed trees
+   *                without children.
+   *  @param  trees  The children to position. All children must be positionable.
+   */
+  private def setChildrenPos(pos: Position, trees: List[Tree]): Unit = try {
+    for (tree <- trees) {
+      if (!tree.isEmpty && tree.canHaveAttrs && tree.pos == NoPosition) {
+        val children = tree.children
+        if (children.isEmpty) {
+          tree setPos pos.focus
+        } else {
+          setChildrenPos(pos, children)
+          tree setPos wrappingPos(pos, children)
+        }
+      }
+    }
+  } catch {
+    case ex: Exception =>
+      println("error while set children pos "+pos+" of "+trees)
+      throw ex
+  }
+
+
+  class ValidateException(msg : String) extends Exception(msg)
 
-  def rangePos(source: SourceFile, start: Int, point: Int, end: Int): Position = new OffsetPosition(source, point)
-  def validatePositions(tree: Tree) {}
+
+  /** A locator for trees with given positions.
+   *  Given a position `pos`, locator.apply returns
+   *  the smallest tree that encloses `pos`.
+   */
+  class Locator(pos: Position) extends Traverser {
+    var last: Tree = _
+    def locateIn(root: Tree): Tree = {
+      this.last = EmptyTree
+      traverse(root)
+      this.last
+    }
+    protected def isEligible(t: Tree) = !t.pos.isTransparent
+    override def traverse(t: Tree) {
+      t match {
+        case tt : TypeTree if tt.original != null && (tt.pos includes tt.original.pos) =>
+          traverse(tt.original)
+        case _ =>
+          if (t.pos includes pos) {
+            if (isEligible(t)) last = t
+            super.traverse(t)
+          } else t match {
+            case mdef: MemberDef =>
+              traverseTrees(mdef.mods.annotations)
+            case _ =>
+          }
+      }
+    }
+  }
+
+  case class Range(pos: Position, tree: Tree) {
+    def isFree = tree == EmptyTree
+  }
+
+  class TypedLocator(pos: Position) extends Locator(pos) {
+    override protected def isEligible(t: Tree) = super.isEligible(t) && t.tpe != null
+  }
 
   trait PosAssigner extends Traverser {
     var pos: Position
@@ -62,9 +296,25 @@ trait Positions extends api.Positions { self: SymbolTable =>
     }
   }
 
+  /** Position a tree.
+   *  This means: Set position of a node and position all its unpositioned children.
+   */
   def atPos[T <: Tree](pos: Position)(tree: T): T = {
-    posAssigner.pos = pos
-    posAssigner.traverse(tree)
-    tree
+    if (useOffsetPositions || !pos.isOpaqueRange) {
+      posAssigner.pos = pos
+      posAssigner.traverse(tree)
+      tree
+    }
+    else {
+      if (!tree.isEmpty && tree.canHaveAttrs && tree.pos == NoPosition) {
+        tree.setPos(pos)
+        val children = tree.children
+        if (children.nonEmpty) {
+          if (children.tail.isEmpty) atPos(pos)(children.head)
+          else setChildrenPos(pos, children)
+        }
+      }
+      tree
+    }
   }
 }