From 8a1424669f6269db0b1ba94d3ab43b75270272bd Mon Sep 17 00:00:00 2001
From: Andreas Rumpf <rumpf_a@web.de>
Date: Mon, 26 Jun 2017 21:03:39 +0200
Subject: [PATCH] optimized diff algorithm further; fixed a stupid bug; cleaned
 up the tests

---
 src/jdict.nim           |   2 +
 src/karax.nim           |  30 +++---
 tests/diffDomTests.html |   1 -
 tests/diffDomTests.nim  | 223 +++++++++++++---------------------------
 tests/difftest.nim      |  29 +++++-
 5 files changed, 117 insertions(+), 168 deletions(-)

diff --git a/src/jdict.nim b/src/jdict.nim
index f541ac7..b239af2 100644
--- a/src/jdict.nim
+++ b/src/jdict.nim
@@ -20,3 +20,5 @@ proc `[]=`*[T](s: JSeq[T], i: int, v: T) {.importcpp: "#[#] = #", noSideEffect.}
 proc newJSeq*[T](): JSeq[T] {.importcpp: "[@]".}
 proc len*[T](s: JSeq[T]): int {.importcpp: "#.length", noSideEffect.}
 proc add*[T](s: JSeq[T]; x: T) {.importcpp: "#.push(#)", noSideEffect.}
+
+proc shrink*[T](s: JSeq[T]; shorterLen: int) {.importcpp: "#.length = #", noSideEffect.}
diff --git a/src/karax.nim b/src/karax.nim
index 3f3ebed..f07bf71 100644
--- a/src/karax.nim
+++ b/src/karax.nim
@@ -208,12 +208,13 @@ type
     parent, current: Node
     n: VNode
 
-proc addPatch(patches: var seq[Patch]; k: PatchKind; parent, current: Node;
+proc addPatch(patches: JSeq[Patch]; k: PatchKind; parent, current: Node;
               n: VNode) =
   patches.add(Patch(k: k, parent: parent, current: current, n: n))
 
-proc apply(patches: seq[Patch]; kxi: KaraxInstance) =
-  for p in patches:
+proc apply(patches: JSeq[Patch]; kxi: KaraxInstance) =
+  for i in 0..<patches.len:
+    let p = patches[i]
     case p.k
     of pkReplace:
       let nn = vnodeToDom(p.n, kxi)
@@ -230,8 +231,7 @@ proc apply(patches: seq[Patch]; kxi: KaraxInstance) =
       let nn = vnodeToDom(p.n, kxi)
       p.parent.insertBefore(nn, p.current)
 
-proc diff(parent, current: Node; newNode, oldNode: VNode; patches: var seq[Patch];
-          kxi: KaraxInstance): EqResult =
+proc diff(newNode, oldNode: VNode;parent, current: Node; patches: JSeq[Patch]): EqResult =
   result = eq(newNode, oldNode)
   case result
   of identical:
@@ -239,7 +239,7 @@ proc diff(parent, current: Node; newNode, oldNode: VNode; patches: var seq[Patch
     let newLength = newNode.len
     var oldLength = oldNode.len
     let minLength = min(newLength, oldLength)
-    if minLength == 0: return result
+    if newLength == 0 and oldLength == 0: return result
 
     assert oldNode.kind == newNode.kind
     var commonPrefix = 0
@@ -254,16 +254,16 @@ proc diff(parent, current: Node; newNode, oldNode: VNode; patches: var seq[Patch
 
       let r = if oldNode.kind == VNodeKind.component or oldNode.kind == VNodeKind.vthunk or
                  oldNode.kind == VNodeKind.dthunk:
-                diff(parent, current, a[i], b[j], patches, kxi)
+                diff(a[i], b[j], parent, current, patches)
               else:
-                diff(current, current.childNodes[j], a[i], b[j], patches, kxi)
+                diff(a[i], b[j], current, current.childNodes[j], patches)
       case r
       of identical, changed, similar:
         a[i] = b[j]
         action
       of different:
         # undo what 'diff' would have done:
-        setLen(patches, oldLen)
+        shrink(patches, oldLen)
         if result != different: result = r
         break
       #of similar:
@@ -284,8 +284,8 @@ proc diff(parent, current: Node; newNode, oldNode: VNode; patches: var seq[Patch
 
     var pos = min(oldPos, newPos) + 1
     for i in commonPrefix..pos-1:
-      if diff(current, current.childNodes[i],
-              newNode[i], oldNode[i], patches, kxi) != different:
+      if diff(newNode[i], oldNode[i], current, current.childNodes[i],
+              patches) != different:
         newNode[i] = oldNode[i]
       else:
         result = different
@@ -318,7 +318,7 @@ proc diff(parent, current: Node; newNode, oldNode: VNode; patches: var seq[Patch
       detach(oldNode)
       patches.addPatch(pkReplace, parent, current, x.expanded)
     else:
-      let res = diff(parent, current, x.expanded, oldExpanded, patches, kxi)
+      let res = diff(x.expanded, oldExpanded, parent, current, patches)
       if res != different:
         x.expanded = oldExpanded
         assert oldExpanded.dom != nil, "old expanded.dom is nil"
@@ -339,8 +339,8 @@ proc dodraw(kxi: KaraxInstance) =
     replaceById(kxi.rootId, asdom)
   else:
     let olddom = document.getElementById(kxi.rootId)
-    var patches: seq[Patch] = @[]
-    discard diff(nil, olddom, newtree, kxi.currentTree, patches, kxi)
+    var patches = newJSeq[Patch]()
+    discard diff(newtree, kxi.currentTree, nil, olddom, patches)
     patches.apply(kxi)
     kxi.currentTree = newtree
   #doAssert same(kxi.currentTree, document.getElementById(kxi.rootId))
@@ -365,6 +365,8 @@ proc redraw*(kxi: KaraxInstance = kxi) =
   else:
     dodraw(kxi)
 
+proc redrawSync*(kxi: KaraxInstance = kxi) = dodraw(kxi)
+
 proc init(ev: Event) =
   reqFrame(proc () = kxi.dodraw)
 
diff --git a/tests/diffDomTests.html b/tests/diffDomTests.html
index 5ecf130..cb6ab28 100644
--- a/tests/diffDomTests.html
+++ b/tests/diffDomTests.html
@@ -3,7 +3,6 @@
 <html>
 <head>
   <title>Diff dom tests</title>
-  <link rel="stylesheet" href="style.css">
 </head>
 
 <body id="body">
diff --git a/tests/diffDomTests.nim b/tests/diffDomTests.nim
index d2c09ab..e28c6f6 100644
--- a/tests/diffDomTests.nim
+++ b/tests/diffDomTests.nim
@@ -2,182 +2,107 @@
 import kdom, vdom, times, karax, karaxdsl, jdict, jstrutils, parseutils, sequtils
 
 var
-    entries: seq[cstring]
-    results: seq[cstring]
-    timeout: Timeout
+  entries: seq[cstring]
+  results: seq[cstring]
 
 proc reset() =
-    results.add cstring"reset started"
-    entries = @[cstring("0"), cstring("1"), cstring("2"), cstring("3"), cstring("4"), cstring("5") ]
-    redraw()
-    results.add cstring"reset finished"
+  entries = @[cstring("0"), cstring("1"), cstring("2"), cstring("3"), cstring("4"), cstring("5")]
+  redrawSync()
 
-proc checkOrder(order : seq[int]): bool =
-    var ul = getElementById("ul")
-    if ul == nil or len(ul.children) != len(order):
-        return false
-    var pos = 0
-    for child in ul.children:
-        if child.id != $order[pos]:
-            return false
-        inc pos
-    return true
+proc checkOrder(order: seq[int]): bool =
+  var ul = getElementById("ul")
+  if ul == nil or len(ul.children) != len(order):
+    kout ul, len(order)
+    return false
+  var pos = 0
+  for child in ul.children:
+    if child.id != $order[pos]:
+      kout pos
+      return false
+    inc pos
+  return true
 
-proc check1() =
-    let result = checkOrder(@[0, 1, 2, 3, 4, 7, 5])
-    if result:
-        results.add cstring"test1 - OK"
-    else:
-        results.add cstring"test1 - FAIL"
+proc check(name: cstring; order: seq[int]) =
+  let result = checkOrder(order)
+  results.add name & (if result: cstring" - OK" else: cstring" -FAIL")
 
 # result: 0 1 2 3 4 7 5
 proc test1() =
-    results.add cstring"test1 started"
-    entries = @[cstring("0"), cstring("1"), cstring("2"), cstring("3"), cstring("4"), cstring("5") ]
-    entries.insert(cstring("7"), 5)
-    redraw()
-    timeout = setTimeout(check1, 20)
+  results.add cstring"test1 started"
+  entries = @[cstring("0"), cstring("1"), cstring("2"), cstring("3"), cstring("4"), cstring("5")]
+  entries.insert(cstring("7"), 5)
+  redrawSync()
+  check("test1", @[0, 1, 2, 3, 4, 7, 5])
 
-proc check2() =
-    let result = checkOrder(@[8, 0, 1, 2, 3, 4, 7, 5])
-    if result:
-        results.add cstring"test1 - OK"
-    else:
-        results.add cstring"test2 - FAIL"
-
-# result: 8 0 1 2 3 4 7 5
 proc test2() =
-    results.add cstring"test2 started"
-    entries = @[cstring("0"), cstring("1"), cstring("2"), cstring("3"), cstring("4"), cstring("5") ]
-    entries.insert(cstring("7"), 5)
-    entries.insert(cstring("8"), 0)
-    redraw()
-    timeout = setTimeout(check2, 20)
+  results.add cstring"test2 started"
+  entries = @[cstring("0"), cstring("1"), cstring("2"), cstring("3"), cstring("4"), cstring("5")]
+  entries.insert(cstring("7"), 5)
+  entries.insert(cstring("8"), 0)
+  redrawSync()
+  check("test2", @[8, 0, 1, 2, 3, 4, 7, 5])
 
-proc check3() =
-    let result = checkOrder(@[2, 3, 4, 1])
-    if result:
-        results.add cstring"test3 - OK"
-    else:
-        results.add cstring"test3 - FAIL"
-
-# result: 2 3 4 1
 proc test3() =
-    results.add cstring"test3 started"
-    entries = @[cstring("2"), cstring("3"), cstring("4"), cstring("1") ]
-    redraw()
-    timeout = setTimeout(check3, 20)
+  results.add cstring"test3 started"
+  entries = @[cstring("2"), cstring("3"), cstring("4"), cstring("1")]
+  redrawSync()
+  check("test3", @[2, 3, 4, 1])
 
-proc check4() =
-    let result = checkOrder(@[5, 6, 7, 8])
-    if result:
-        results.add cstring"test4 - OK"
-    else:
-        results.add cstring"test4 - FAIL"
-
-# result: 5 6 7 8
 proc test4() =
-    results.add cstring"test4 started"
-    entries = @[cstring("5"), cstring("6"), cstring("7"), cstring("8") ]
-    redraw()
-    timeout = setTimeout(check4, 20)
+  results.add cstring"test4 started"
+  entries = @[cstring("5"), cstring("6"), cstring("7"), cstring("8") ]
+  redrawSync()
+  check("test4", @[5, 6, 7, 8])
 
-proc check5() =
-    let result = checkOrder(@[0, 1, 3, 5, 4, 5])
-    if result:
-        results.add cstring"test5 - OK"
-    else:
-        results.add cstring"test5 - FAIL"
-
-# result: 0 1 3 5 4 5
 proc test5() =
-    results.add cstring"test5 started"
-    entries = @[cstring("0"), cstring("1"), cstring("3"), cstring("5"), cstring("4"), cstring("5") ]
-    redraw()
-    timeout = setTimeout(check5, 20)
+  results.add cstring"test5 started"
+  entries = @[cstring("0"), cstring("1"), cstring("3"), cstring("5"), cstring("4"), cstring("5")]
+  redrawSync()
+  check("test 5", @[0, 1, 3, 5, 4, 5])
 
-proc check6() =
-    let result = checkOrder(@[])
-    if result:
-        results.add cstring"test6 - OK"
-    else:
-        results.add cstring"test6 - FAIL"
-
-# result: empty
 proc test6() =
-    results.add cstring"test6 started"
-    entries = @[]
-    redraw()
-    timeout = setTimeout(check6, 20)
-
-proc check7() =
-    let result = checkOrder(@[2])
-    if result:
-        results.add cstring"test7 - OK"
-    else:
-        results.add cstring"test7 - FAIL"
-    redraw()
+  results.add cstring"test6 started"
+  entries = @[]
+  redrawSync()
+  check("test 6", @[])
 
 # result: 2
 proc test7() =
-    results.add cstring"test7 started"
-    entries = @[cstring("2")]
-    redraw()
-    timeout = setTimeout(check7, 20)
+  results.add cstring"test7 started"
+  entries = @[cstring("2")]
+  redrawSync()
+  check("test 7", @[2])
 
 proc createEntry(id: int): VNode =
   result = buildHtml():
     button(id="" & $id):
-        text $id
+      text $id
 
 proc createDom(): VNode =
-    result = buildHtml(tdiv()):
-        ul(id="ul"):
-            for e in entries:
-                createEntry(parseInt(e))
-        for r in results:
-            tdiv:
-                text r
+  result = buildHtml(tdiv()):
+    ul(id="ul"):
+      for e in entries:
+        createEntry(parseInt(e))
+    for r in results:
+      tdiv:
+        text r
 
 proc onload() =
-    for i in 0..5: # 0_000:
-        entries.add(cstring($i))
+  for i in 0..5: # 0_000:
+    entries.add(cstring($i))
+  test1()
+  reset()
+  test2()
+  reset()
+  test3()
+  reset()
+  test4()
+  reset()
+  test5()
+  reset()
+  test6()
+  reset()
+  test7()
 
-    var dtReset = 100
-    var dtTest = 500
-
-    var t = dtReset
-    timeout = setTimeout(test1, t)
-    t += dtTest
-    timeout = setTimeout(reset, t)
-    t += dtReset
-
-    timeout = setTimeout(test2, t)
-    t += dtTest
-    timeout = setTimeout(reset, t)
-    t += dtReset
-
-    timeout = setTimeout(test3, t)
-    t += dtTest
-    timeout = setTimeout(reset, t)
-    t += dtReset
-
-    timeout = setTimeout(test4, t)
-    t += dtTest
-    timeout = setTimeout(reset, t)
-    t += dtReset
-
-    timeout = setTimeout(test5, t)
-    t += dtTest
-    timeout = setTimeout(reset, t)
-    t += dtReset
-
-    timeout = setTimeout(test6, t)
-    t += dtTest
-    timeout = setTimeout(reset, t)
-    t += dtReset
-
-    timeout = setTimeout(test7, t)
-
-onload()
 setRenderer createDom
+onload()
diff --git a/tests/difftest.nim b/tests/difftest.nim
index 9f80037..bd90b6a 100644
--- a/tests/difftest.nim
+++ b/tests/difftest.nim
@@ -2,10 +2,19 @@
 include "../src/karax"
 import "../src/karaxdsl"
 
+proc hasDom(n: Vnode) =
+  if n.kind in {VNodeKind.component, VNodeKind.vthunk, VNodeKind.dthunk}:
+    discard
+  else:
+    doAssert n.dom != nil
+    for i in 0..<n.len: hasDom(n[i])
+
 proc doDiff(a, b: VNode) =
-  var patches: seq[Patch] = @[]
-  echo diff(nil, vnodeToDom(a, kxi), b, a, patches, kxi)
-  echo patches
+  var patches = newJSeq[Patch]()
+  echo diff(b, a, nil, vnodeToDom(a, kxi), patches)
+  for i in 0..<patches.len:
+    echo patches[i]
+  #hasDom(kxi.currentTree)
 
 proc testAppend() =
   let a = buildHtml(tdiv):
@@ -31,7 +40,19 @@ proc testInsert() =
       li: text "C"
   doDiff(a, b)
 
+proc testDelete() =
+  let a = buildHtml(tdiv):
+    ul:
+      li: text "A"
+      li: text "B"
+      li: text "C"
+  let b = buildHtml(tdiv):
+    ul:
+      discard
+  doDiff(a, b)
+
 kxi = KaraxInstance(rootId: cstring"ROOT", renderer: proc (): VNode = discard)
 
-#testAppend()
+testAppend()
 testInsert()
+testDelete()