Tweaks to pickle format

MODULE -> OBJECT, as suggested by Simon.
Header is 4 hex digits, not 8 chars.

Author: odersky

src/dotty/tools/dotc/core/pickling/NameBuffer.scala

@@ -69,7 +69,7 @@ class NameBuffer extends TastyBuffer(100000) {
       writeByte(EXPANDED)
       withLength { writeNameRef(original) }
     case ModuleClass(module) =>
-      writeByte(MODULECLASS)
+      writeByte(OBJECTCLASS)
       withLength { writeNameRef(module) }
     case SuperAccessor(accessed) =>
       writeByte(SUPERACCESSOR)

src/dotty/tools/dotc/core/pickling/PickleFormat.scala

@@ -23,7 +23,7 @@ Macro-format:
 
   File          = Header majorVersion_Nat minorVersion_Nat UUID
                   nameTable_Length Name* Section*
-  Header        = "5CA1AB1F"
+  Header        = 0x5CA1AB1F
   UUID          = Byte*16                // random UUID
 
   Section       = NameRef Length Bytes
@@ -33,7 +33,7 @@ Macro-format:
                   QUALIFIED      Length qualified_NameRef selector_NameRef
                   SIGNED         Length original_NameRef resultSig_NameRef paramSig_NameRef*
                   EXPANDED       Length original_NameRef
-                  MODULECLASS    Length module_NameRef
+                  OBJECTCLASS    Length module_NameRef
                   SUPERACCESSOR  Length accessed_NameRef
                   DEFAULTGETTER  Length method_NameRef paramNumber_Nat
                   SHADOWED       Length original_NameRef
@@ -160,7 +160,7 @@ Standard-Section: "ASTs" TopLevelStat*
                   INLINE                // macro
                   ABSOVERRIDE					  // abstract override
                   STATIC						    // mapped to static Java member
-                  MODULE						    // an object or its class
+                  OBJECT						    // an object or its class
                   TRAIT                 // a trait
                   LOCAL						      // private[this] or protected[this]
                   SYNTHETIC					    // generated by Scala compiler
@@ -205,7 +205,7 @@ Standard Section: "Positions" sourceLength_Nat Assoc*
 
 object PickleFormat {
 
-  final val header = "5CA1AB1F"
+  final val header = Array(0x5C, 0xA1, 0xAB, 0x1F)
   final val MajorVersion = 0
   final val MinorVersion = 5
 
@@ -215,7 +215,7 @@ object PickleFormat {
   final val QUALIFIED = 2
   final val SIGNED = 3
   final val EXPANDED = 4
-  final val MODULECLASS = 5
+  final val OBJECTCLASS = 5
   final val SUPERACCESSOR = 6
   final val DEFAULTGETTER = 7
   final val SHADOWED = 8
@@ -239,7 +239,7 @@ object PickleFormat {
   final val INLINE = 16
   final val ABSOVERRIDE = 17
   final val STATIC = 18
-  final val MODULE = 19
+  final val OBJECT = 19
   final val TRAIT = 20
   final val LOCAL = 21
   final val SYNTHETIC = 22
@@ -350,7 +350,7 @@ object PickleFormat {
        | INLINE
        | ABSOVERRIDE
        | STATIC
-       | MODULE
+       | OBJECT
        | TRAIT
        | LOCAL
        | SYNTHETIC
@@ -375,7 +375,7 @@ object PickleFormat {
     case QUALIFIED => "QUALIFIED"
     case SIGNED => "SIGNED"
     case EXPANDED => "EXPANDED"
-    case MODULECLASS => "MODULECLASS"
+    case OBJECTCLASS => "OBJECTCLASS"
     case SUPERACCESSOR => "SUPERACCESSOR"
     case DEFAULTGETTER => "DEFAULTGETTER"
   }
@@ -398,7 +398,7 @@ object PickleFormat {
     case INLINE => "INLINE"
     case ABSOVERRIDE => "ABSOVERRIDE"
     case STATIC => "STATIC"
-    case MODULE => "MODULE"
+    case OBJECT => "OBJECT"
     case TRAIT => "TRAIT"
     case LOCAL => "LOCAL"
     case SYNTHETIC => "SYNTHETIC"

src/dotty/tools/dotc/core/pickling/TastyPickler.scala

@@ -13,7 +13,7 @@ class TastyPickler {
   private val sections = new mutable.ArrayBuffer[(TastyName.NameRef, TastyBuffer)]
 
   private val headerBuffer = {
-    val buf = new TastyBuffer(28)
+    val buf = new TastyBuffer(24)
     for (ch <- header) buf.writeByte(ch.toByte)
     buf.writeNat(MajorVersion)
     buf.writeNat(MinorVersion)

src/dotty/tools/dotc/core/pickling/TastyUnpickler.scala

@@ -52,7 +52,7 @@ class TastyUnpickler(reader: TastyReader) {
         Signed(original, params, result)
       case EXPANDED =>
         Expanded(readNameRef())
-      case MODULECLASS =>
+      case OBJECTCLASS =>
         ModuleClass(readNameRef())
       case SUPERACCESSOR =>
         SuperAccessor(readNameRef())
@@ -65,9 +65,9 @@ class TastyUnpickler(reader: TastyReader) {
     result
   }
 
-  private def readHeader() = {
-    val magic = readBytes(8)
-    check(magic.map(_.toChar).mkString == header, "not a TASTy file")
+  private def readHeader(): UUID = {
+    for (i <- 0 until header.length)
+      check(readByte() == header(i), "not a TASTy file")
     val major = readNat()
     val minor = readNat()
     check(major == MajorVersion && minor <= MinorVersion, 

src/dotty/tools/dotc/core/pickling/TreePickler.scala

@@ -502,7 +502,7 @@ class TreePickler(pickler: TastyPickler) {
       if (flags is Override) writeByte(OVERRIDE)
       if (flags is Inline) writeByte(INLINE)
       if (flags is JavaStatic) writeByte(STATIC)
-      if (flags is Module) writeByte(MODULE)
+      if (flags is Module) writeByte(OBJECT)
       if (flags is Local) writeByte(LOCAL)
       if (flags is Synthetic) writeByte(SYNTHETIC)
       if (flags is Artifact) writeByte(ARTIFACT)

src/dotty/tools/dotc/core/pickling/TreeUnpickler.scala

@@ -425,7 +425,7 @@ class TreeUnpickler(reader: TastyReader, tastyName: TastyName.Table) {
           case INLINE => addFlag(Inline)
           case ABSOVERRIDE => addFlag(AbsOverride)
           case STATIC => addFlag(JavaStatic)
-          case MODULE => addFlag(Module)
+          case OBJECT => addFlag(Module)
           case TRAIT => addFlag(Trait)
           case LOCAL => addFlag(Local)
           case SYNTHETIC => addFlag(Synthetic)