DOM diff problem: hashing

diffDomTests.nim

@@ -176,6 +176,3 @@ proc onload(session: cstring) {.exportc.} =
     t += dtReset
 
     timeout = setTimeout(test7, t)
-    t += dtTest
-    timeout = setTimeout(reset, t)
-    t += dtReset

karax.nim

@@ -109,16 +109,65 @@ proc equals(a, b: VNode): bool =
       a.class = b.class
   return true
 
+proc getStringHash(s: string): uint64 =
+  result = 0
+  for c in s:
+    result = (result * 257 + uint64(c)) mod 1000000007
+
+proc calcHash(a : VNode) = 
+  if a.validHash:
+    return
+  var result : uint64 = 0
+  for i in a:
+    i.calcHash()
+    result = result + i.hash
+  a.validHash = true
+  a.hash = (getStringHash(getVNodeData(a)) * 71 + result) mod 1000000007
+
 proc equalsTree(a, b : VNode): bool =
-  if not equals(a, b):
-    return false
-  else:
-    if len(a) != len(b):
-      return false
-    for i in 0..len(a)-1:
-      if not equalsTree(a[i], b[i]):
-        return false
-    return true
+  if not a.validHash:
+    a.calcHash()
+  if not b.validHash:
+    b.calcHash()
+
+  return a.hash == b.hash
+
+  # if not equals(a, b):
+  #   return false
+  # else:
+  #   if len(a) != len(b):
+  #     return false
+  #   for i in 0..len(a)-1:
+  #     if not equalsTree(a[i], b[i]):
+  #       return false
+  #   return true
+  
+  # kout cstring("a " & $int64(a.hash) & " " & "b " & $int64(b.hash))
+
+  # if not equals(a, b):
+  #   if a.hash == b.hash:
+  #     kout cstring("false " & getVNodeData(a) & " " & $int64(a.hash) & " " & getVNodeData(b) & " " & $int64(b.hash))
+  #     kout cstring($int64(getStringHash(getVNodeData(a))) & " " & $int64(getStringHash(getVNodeData(b))))
+  #     for c in getVNodeData(a):
+  #       kout cstring($int64(uint64(c)))
+  #     kout "-------"
+  #     for c in getVNodeData(b):
+  #       kout cstring($int64(uint64(c)))
+      
+  #   return false
+  # else:
+  #   if len(a) != len(b):
+  #     if a.hash == b.hash:
+  #         kout cstring("false " & getVNodeData(a) & " " & $int64(a.hash) & " " & getVNodeData(b) & " " & $int64(b.hash))
+  #     return false
+  #   for i in 0..len(a)-1:
+  #     if not equalsTree(a[i], b[i]):
+  #       if a.hash == b.hash:
+  #         kout cstring("false " & getVNodeData(a) & " " & $int64(a.hash) & " " & getVNodeData(b) & " " & $int64(b.hash))
+  #       return false
+  #   if a.hash != b.hash:
+  #       kout cstring("true " & getVNodeData(a) & " " & getVNodeData(b))
+  #   return true
 
 proc updateElement(parent, current: Node, newNode, oldNode: VNode) =
   if not equals(newNode, oldNode):
@@ -137,7 +186,7 @@ proc updateElement(parent, current: Node, newNode, oldNode: VNode) =
         kout current.nodeName
         kout toTag[oldNode.kind]
         assert false
-
+      
     var commonPrefix = 0
     while commonPrefix < minLength and equalsTree(newNode[commonPrefix], oldNode[commonPrefix]):
       inc commonPrefix

vdom.nim

@@ -38,6 +38,8 @@ type
     # even index: key, odd index: value; done this way for memory efficiency:
     attrs: seq[cstring]
     events*: seq[(EventKind, EventHandler)]
+    hash*: uint64
+    validHash*: bool
 
 proc value*(n: VNode): cstring = n.text
 proc `value=`*(n: VNode; v: cstring) = n.text = v
@@ -129,6 +131,24 @@ proc toString*(n: VNode; result: var string; indent: int) =
   for i in 1..indent: result.add ' '
   result.add "\L</" & $n.kind & ">"
 
+proc getVNodeData*(n: VNode): string =
+  result.add "<" & $n.kind
+  toStringAttr(id)
+  toStringAttr(class)
+  
+  #for k, v in attrs(n):
+  #  result.add " " & $k & " = " & $v
+  
+  result.add ">"
+  if n.kind == VNodeKind.text:
+    result.add n.text
+  else:
+    if n.text != nil:
+      result.add " value = "
+      result.add n.text
+  result.add "</" & $n.kind & ">"
+  
+
 proc `$`*(n: VNode): cstring =
   var res = ""
   toString(n, res, 0)