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/* NSC -- new Scala compiler
* Copyright 2009-2013 Typesafe/Scala Solutions and LAMP/EPFL
* @author Martin Odersky
*/
package scala.tools.nsc
package interactive
import ast.Trees
import ast.Positions
import scala.reflect.internal.util.{SourceFile, Position, RangePosition, NoPosition}
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 RangePositions extends Trees with Positions {
self: scala.tools.nsc.Global =>
case class Range(pos: Position, tree: Tree) {
def isFree = tree == EmptyTree
}
override def rangePos(source: SourceFile, start: Int, point: Int, end: Int) =
new RangePosition(source, start, point, end)
/** 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.
*/
override def wrappingPos(default: Position, trees: List[Tree], focus: Boolean): Position = {
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 a 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 ranges, returns a range position enclosing all ranges
* Otherwise returns first tree's position.
*/
override def wrappingPos(trees: List[Tree]): Position = {
val headpos = trees.head.pos
if (headpos.isDefined) wrappingPos(headpos, trees) else headpos
}
// -------------- ensuring no overlaps -------------------------------
/** Ensure that given tree has no positions that overlap with
* any of the positions of `others`. This is done by
* shortening the range, assigning TransparentPositions
* to some of the nodes in `tree` or focusing on the position.
*/
override def ensureNonOverlapping(tree: Tree, others: List[Tree], focus: Boolean) {
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 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()
}
// -------------- setting positions -------------------------------
/** 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.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
}
/** Position a tree.
* This means: Set position of a node and position all its unpositioned children.
*/
override def atPos[T <: Tree](pos: Position)(tree: T): T = {
if (pos.isOpaqueRange) {
if (!tree.isEmpty && 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
} else {
super.atPos(pos)(tree)
}
}
// ---------------- Validating positions ----------------------------------
override def validatePositions(tree: Tree) {
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) {
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 (phase.id <= currentRun.typerPhase.id)
validate(tree, tree)
}
class ValidateException(msg : String) extends Exception(msg)
// ---------------- Locating trees ----------------------------------
/** 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 _ =>
}
}
}
}
class TypedLocator(pos: Position) extends Locator(pos) {
override protected def isEligible(t: Tree) = super.isEligible(t) && t.tpe != null
}
}
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