Add UUID to Tasty

Tasty files now always carry a random UUID.

4 files changed, 20 insertions, 10 deletions

diff --git a/src/dotty/tools/dotc/core/pickling/PickleFormat.scala b/src/dotty/tools/dotc/core/pickling/PickleFormat.scala
index e4bd95af2..42a1cc1b5 100644
--- a/src/dotty/tools/dotc/core/pickling/PickleFormat.scala
+++ b/src/dotty/tools/dotc/core/pickling/PickleFormat.scala
@@ -22,8 +22,9 @@ Micro-syntax:
 
 Macro-format:
 
-  File          = Header majorVersion_Nat minorVersion_Nat nameTable_Length Name* Section*
+  File          = Header majorVersion_Nat minorVersion_Nat UUID nameTable_Length Name* Section*
   Header        = "5CA1AB1F"
+  UUID          = Byte*16
 
   Section       = NameRef Length Bytes
   Length        = Nat                    // length of rest of entry in bytes
diff --git a/src/dotty/tools/dotc/core/pickling/TastyPickler.scala b/src/dotty/tools/dotc/core/pickling/TastyPickler.scala
index 32cc1ae43..ee0e5a8fa 100644
--- a/src/dotty/tools/dotc/core/pickling/TastyPickler.scala
+++ b/src/dotty/tools/dotc/core/pickling/TastyPickler.scala
@@ -6,16 +6,20 @@ package pickling
 import PickleFormat._
 import collection.mutable
 import TastyBuffer._
+import java.util.UUID
 
 class TastyPickler {
       
   private val sections = new mutable.ArrayBuffer[(TastyName.NameRef, TastyBuffer)]
   
   private val headerBuffer = {
-    val buf = new TastyBuffer(16)
+    val buf = new TastyBuffer(28)
     for (ch <- header) buf.writeByte(ch.toByte)
     buf.writeNat(MajorVersion)
     buf.writeNat(MinorVersion)
+    val uuid = UUID.randomUUID()
+    buf.writeUncompressedLong(uuid.getMostSignificantBits)
+    buf.writeUncompressedLong(uuid.getLeastSignificantBits)
     buf
   }
 
diff --git a/src/dotty/tools/dotc/core/pickling/TastyPrinter.scala b/src/dotty/tools/dotc/core/pickling/TastyPrinter.scala
index 8a6ce0221..d4b4330e8 100644
--- a/src/dotty/tools/dotc/core/pickling/TastyPrinter.scala
+++ b/src/dotty/tools/dotc/core/pickling/TastyPrinter.scala
@@ -10,7 +10,7 @@ import TastyUnpickler._
 class TastyPrinter(bytes: Array[Byte])(implicit ctx: Context) {
   
   val unpickler = new TastyUnpickler(bytes)
-  import unpickler.{tastyName, unpickled}
+  import unpickler.{tastyName, unpickle}
   
   def nameToString(name: TastyName): String = name match {
     case Simple(name) => name.toString
@@ -33,7 +33,7 @@ class TastyPrinter(bytes: Array[Byte])(implicit ctx: Context) {
     println("Names:")
     printNames()
     println("Trees:")
-    unpickled(new TreeUnpickler)
+    unpickle(new TreeUnpickler)
   }
   
   class TreeUnpickler extends SectionUnpickler[Unit]("ASTs") {
diff --git a/src/dotty/tools/dotc/core/pickling/TastyUnpickler.scala b/src/dotty/tools/dotc/core/pickling/TastyUnpickler.scala
index f2d075446..596b7542d 100644
--- a/src/dotty/tools/dotc/core/pickling/TastyUnpickler.scala
+++ b/src/dotty/tools/dotc/core/pickling/TastyUnpickler.scala
@@ -5,6 +5,7 @@ package pickling
 import scala.collection.mutable
 import PickleFormat._
 import Names.{Name, termName}
+import java.util.UUID
 
 object TastyUnpickler {  
   class UnpickleException(msg: String) extends Exception(msg)
@@ -62,17 +63,21 @@ class TastyUnpickler(reader: TastyReader) {
     result
   }
   
-  locally {
+  private def readHeader() = {
     val magic = readBytes(8)
     check(magic.map(_.toChar).mkString == header, "not a TASTy file")
     val major = readNat()
     val minor = readNat()
-    def versionMsg = 
+    check(major == MajorVersion && minor <= MinorVersion, 
       s"""TASTy signature has wrong version.
          | expected: $MajorVersion.$MinorVersion
-         | found   : $major.$minor""".stripMargin
-    check(major == MajorVersion, versionMsg)
-    if (MajorVersion == 0) check(minor == MinorVersion, versionMsg)
+         | found   : $major.$minor""".stripMargin)
+    new UUID(readUncompressedLong(), readUncompressedLong())
+  }
+  
+  val uuid = readHeader()
+  
+  locally {
     until(readEnd()) { tastyName.add(readName()) }
     while (!isAtEnd) {
       val secName = readString()
@@ -82,7 +87,7 @@ class TastyUnpickler(reader: TastyReader) {
     }
   }
   
-  def unpickled[R](sec: SectionUnpickler[R]): Option[R] = 
+  def unpickle[R](sec: SectionUnpickler[R]): Option[R] = 
     for (reader <- sectionReader.get(sec.name)) yield
       sec.unpickle(reader, tastyName)
 }