Add KeyedVectorAttr, make adapter.metadata accessible through WorldEditor

Add AnvilWorldMetadata.Spawn
Add KeyedVectorAttr, used for Spawn and TileEntity Position
Remove get/setWorldSpawnPosition

src/mcedit2/editorsession.py

@@ -693,7 +693,7 @@ class EditorSession(QtCore.QObject):
                     pass
             except PlayerNotFound:
                 try:
-                    center = self.worldEditor.worldSpawnPosition()
+                    center = self.worldEditor.getWorldMetadata().Spawn
                     log.info("Centering on spawn position.")
                 except AttributeError:
                     log.info("Centering on world center")

src/mcedit2/panels/worldinfo.py

@@ -90,7 +90,7 @@ class WorldInfoPanel(QtGui.QWidget):
         self.generatorSeedLineEdit.setText(str(self.worldMeta.RandomSeed))
         self.generatorOptionsLineEdit.setText(self.worldMeta.generatorOptions)
 
-        sx, sy, sz = self.worldMeta.worldSpawnPosition()
+        sx, sy, sz = self.worldMeta.Spawn
         self.spawnX.setValue(sx)
         self.spawnY.setValue(sy)
         self.spawnZ.setValue(sz)
@@ -201,7 +201,7 @@ class WorldInfoPanel(QtGui.QWidget):
 
         command = WorldMetaEditCommand(self.editorSession, self.tr('Change Spawn Coordinates'))
         with command.begin():
-            self.worldMeta.setWorldSpawnPosition(self.spawnX.value(), self.spawnY.value(), self.spawnZ.value())
+            self.worldMeta.Spawn = self.spawnX.value(), self.spawnY.value(), self.spawnZ.value()
         self.editorSession.pushCommand(command)
 
     def timeChanged(self):

src/mcedit2/worldlist.py

@@ -384,7 +384,7 @@ class WorldListWidget(QtGui.QDialog):
                     log.info("Centering on single-player player.")
                 except PlayerNotFound:
                     try:
-                        center = worldEditor.worldSpawnPosition()
+                        center = worldEditor.getWorldMetadata().Spawn
                         log.info("Centering on spawn position.")
                     except AttributeError:
                         log.info("Centering on world center")

src/mceditlib/anvil/adapter.py

@@ -374,25 +374,20 @@ class AnvilWorldMetadata(object):
 
     version = nbtattr.NBTAttr('version', nbt.TAG_Int, VERSION_ANVIL)
 
-    def worldSpawnPosition(self):
-        return Vector(*[self.rootTag[i].value for i in ("SpawnX", "SpawnY", "SpawnZ")])
-
-    def setWorldSpawnPosition(self, pos):
-        for name, val in zip(("SpawnX", "SpawnY", "SpawnZ"), pos):
-            self.rootTag[name] = nbt.TAG_Int(val)
+    Spawn = nbtattr.KeyedVectorAttr('SpawnX', 'SpawnY', 'SpawnZ', nbt.TAG_Int)
 
     def is1_8World(self):
         # Minecraft 1.8 adds a dozen tags to level.dat/Data. These tags are removed if
         # the world is played in 1.7 (and all of the items are removed too!)
         # Use some of these tags to decide whether to use 1.7 format ItemStacks or 1.8 format ones.
-        # In 1.8, the stack's "id" is a string, but in 1.7 it is an int.
-        tags = (t in self.rootTag for t in (
+        # In 1.8, the stack's "id" is a TAG_String, but in 1.7 it is a TAG_Short.
+        tags = (
             'BorderCenterX', 'BorderCenterZ',
             'BorderDamagePerBlock',
             'BorderSafeZone',
             'BorderSize'
-        ))
-        return any(tags)
+        )
+        return any(tag in self.rootTag for tag in tags)
 
 class AnvilWorldAdapter(object):
     """

src/mceditlib/anvil/entities.py

@@ -63,15 +63,7 @@ class PCTileEntityRefBase(object):
         return self.rootTag
 
     id = nbtattr.NBTAttr("id", nbt.TAG_String)
-
-    @property
-    def Position(self):
-        return Vector(*[self.rootTag[c].value for c in 'xyz'])
-
-    @Position.setter
-    def Position(self, pos):
-        for a, p in zip('xyz', pos):
-            self.rootTag[a] = nbt.TAG_Int(p)
+    Position = nbtattr.KeyedVectorAttr('x', 'y', 'z', nbt.TAG_Int, 0)
 
     def copy(self):
         return self.copyWithOffset(Vector(0, 0, 0))

src/mceditlib/minecraft_server.py

@@ -356,7 +356,7 @@ class MCServerChunkGenerator(object):
 
     def generateAtPositionIter(self, tempWorld, tempDir, cx, cz, simulate=False):
         tempWorldRW = worldeditor.WorldEditor(tempWorld.filename)
-        tempWorldRW.setWorldSpawnPosition((cx * 16, 64, cz * 16))
+        tempWorldRW.getWorldMetadata().Spawn = cx * 16, 64, cz * 16
         tempWorldRW.saveChanges()
         tempWorldRW.close()
         del tempWorldRW

src/mceditlib/nbtattr.py

@@ -275,6 +275,37 @@ class NBTVectorAttr(NBTListAttr):
         return Vector(*val)
 
 
+class KeyedVectorAttr(object):
+    """
+    This attr is useful when a Vector is represented as a trio of named tags in a compound
+    instead of as a list of tags. For example, the world spawn position (SpawnX, SpawnY,
+    SpawnZ) and a TileEntity's position (x, y, z).
+    """
+    def __init__(self, xKey, yKey, zKey, tagType, default=None):
+        self.tagType = tagType
+        self.default = default
+        self.keys = xKey, yKey, zKey
+
+    def __get__(self, instance, owner):
+        tag = instance.rootTag
+        for key in self.keys:
+            if key not in tag:
+                tag[key] = self.tagType(value=self.default)
+
+        return Vector(*[tag[k].value for k in self.keys])
+
+    def __set__(self, instance, value):
+        tag = instance.rootTag
+        for key, val in zip(self.keys, value):
+            if key not in tag:
+                tag[key] = self.tagType(val)
+            else:
+                tag[key].value = val
+
+        instance.dirty = True
+
+
+
 def SetNBTDefaults(ref):
     """
     Given an object whose class has several members of type `NBT[*]Attr`,

src/mceditlib/worldeditor.py

@@ -529,21 +529,21 @@ class WorldEditor(object):
         if self._allChunks is not None:
             self._allChunks[dimName].discard((cx, cz))
 
-    # --- Player and spawn manipulation ---
+    # --- World metadata ---
 
-    def worldSpawnPosition(self):
+    def getWorldMetadata(self):
         """
-        Return the world's default spawn position.
-        """
-        return self.adapter.metadata.worldSpawnPosition()
+        Return an object containing global info about the world.
 
-    def setWorldSpawnPosition(self, pos):
-        """
-        Change the world's default spawn position.
+        Different level formats can return different objects for the world metadata.
+        At the very least, you can expect the object to have Spawn and Seed attributes.
 
-        :param pos: (x, y, z) coordinates
+        Currently, only AnvilWorldMetadata is ever returned.
+        :return:
         """
-        self.adapter.metadata.setWorldSpawnPosition(pos)
+        return self.adapter.metadata
+
+    # --- Players ---
 
     def listPlayers(self):
         return self.adapter.listPlayers()