@@ -20,73 +20,45 @@ package jsonpatch
2020import lcs ._
2121import jsonpointer ._
2222
23- import cats .implicits ._
23+ import cats .syntax .all ._
24+ import cats .data .Chain
25+ import cats .Eval
2426
2527import scala .annotation .tailrec
2628
2729class JsonDiff [Json ](diffArray : Boolean , rememberOld : Boolean )(implicit J : Jsony [Json ], Lcs : Lcs [Json ])
2830 extends Diff [Json , JsonPatch [Json ]] {
2931 def diff (json1 : Json , json2 : Json ): JsonPatch [Json ] =
30- JsonPatch (diff(json1, json2, Pointer .Root ))
32+ JsonPatch (diff(json1, json2, Pointer .Root ).value.toList )
3133
32- private def diff (json1 : Json , json2 : Json , pointer : Pointer ): List [Operation [Json ]] =
33- if (json1 === json2)
34- // if they are equal, this one is easy...
35- Nil
36- else
37- (json1, json2) match {
38- case (JsObject (fields1), JsObject (fields2)) => fieldsDiff(fields1.toList, fields2.toList, pointer)
39- case (JsArray (arr1), JsArray (arr2)) if diffArray => arraysDiff(arr1.toList, arr2.toList, pointer)
40- case (_, _) => List (Replace (pointer, json2, if (rememberOld) Some (json1) else None ))
41- }
34+ private def diff (json1 : Json , json2 : Json , pointer : Pointer ): Eval [Chain [Operation [Json ]]] =
35+ (json1, json2) match {
36+ case (JsObject (fields1), JsObject (fields2)) => fieldsDiff(fields1.toList, fields2, pointer)
37+ case (JsArray (arr1), JsArray (arr2)) if diffArray => arraysDiff(arr1.toList, arr2.toList, pointer)
38+ case _ if json1 === json2 =>
39+ // if they are equal, this one is easy...
40+ Eval .now(Chain .empty)
41+ case _ => Eval .now(Chain .one(Replace (pointer, json2, if (rememberOld) Some (json1) else None )))
42+ }
4243
4344 private def fieldsDiff (fields1 : List [(String , Json )],
44- fields2 : List [(String , Json )],
45- path : Pointer ): List [Operation [Json ]] = {
46- // sort fields by name in both objects
47- val sorted1 = fields1.sortBy(_._1)
48- val sorted2 = fields2.sortBy(_._1)
49- @ tailrec
50- def associate (fields1 : List [(String , Json )],
51- fields2 : List [(String , Json )],
52- acc : List [(Option [(String , Json )], Option [(String , Json )])])
53- : List [(Option [(String , Json )], Option [(String , Json )])] = (fields1, fields2) match {
54- case (f1 :: t1, f2 :: t2) if f1._1 == f2._1 =>
55- // same name, associate both
56- associate(t1, t2, (Some (f1), Some (f2)) :: acc)
57- case (f1 :: t1, f2 :: _) if f1._1 < f2._1 =>
58- // the first field is not present in the second object
59- associate(t1, fields2, (Some (f1), None ) :: acc)
60- case (_ :: _, f2 :: t2) =>
61- // the second field is not present in the first object
62- associate(fields1, t2, (None , Some (f2)) :: acc)
63- case (_, Nil ) =>
64- fields1.map(Some (_) -> None ) ::: acc
65- case (Nil , _) =>
66- fields2.map(None -> Some (_)) ::: acc
45+ fields2 : Map [String , Json ],
46+ path : Pointer ): Eval [Chain [Operation [Json ]]] =
47+ fields1 match {
48+ case (fld, value1) :: fields1 =>
49+ fields2.get(fld) match {
50+ case Some (value2) =>
51+ fieldsDiff(fields1, fields2 - fld, path).flatMap(d => diff(value1, value2, path / fld).map(_ ++ d))
52+ case None =>
53+ // field is not in the second object, delete it
54+ fieldsDiff(fields1, fields2, path).map(
55+ _.prepend(Remove (path / fld, if (rememberOld) Some (value1) else None )))
56+ }
57+ case Nil =>
58+ Eval .now(Chain .fromSeq(fields2.toList).map { case (fld, value) => Add (path / fld, value) })
6759 }
68- @ tailrec
69- def fields (fs : List [(Option [(String , Json )], Option [(String , Json )])],
70- acc : List [Operation [Json ]]): List [Operation [Json ]] = fs match {
71- case (Some (f1), Some (f2)) :: tl if f1 == f2 =>
72- // all right, nothing changed
73- fields(tl, acc)
74- case (Some (f1), Some (f2)) :: tl =>
75- // same field name, different values
76- fields(tl, diff(f1._2, f2._2, path / f1._1) ::: acc)
77- case (Some (f1), None ) :: tl =>
78- // the field was deleted
79- fields(tl, Remove [Json ](path / f1._1, if (rememberOld) Some (f1._2) else None ) :: acc)
80- case (None , Some (f2)) :: tl =>
81- // the field was added
82- fields(tl, Add (path / f2._1, f2._2) :: acc)
83- case _ =>
84- acc
85- }
86- fields(associate(sorted1, sorted2, Nil ), Nil )
87- }
8860
89- private def arraysDiff (arr1 : List [Json ], arr2 : List [Json ], path : Pointer ): List [ Operation [Json ]] = {
61+ private def arraysDiff (arr1 : List [Json ], arr2 : List [Json ], path : Pointer ): Eval [ Chain [ Operation [Json ] ]] = {
9062 // get the longest common subsequence in the array
9163 val lcs = Lcs .lcs(arr1, arr2)
9264
@@ -104,27 +76,27 @@ class JsonDiff[Json](diffArray: Boolean, rememberOld: Boolean)(implicit J: Jsony
10476
10577 // add a bunch of values to an array starting at the specified index
10678 @ tailrec
107- def add (arr : List [Json ], idx : Int , acc : List [Operation [Json ]]): List [Operation [Json ]] = arr match {
108- case v :: tl => add(tl, idx + 1 , Add (path / idx, v) :: acc )
109- case Nil => acc.reverse
79+ def add (arr : List [Json ], idx : Int , acc : Chain [Operation [Json ]]): Chain [Operation [Json ]] = arr match {
80+ case v :: tl => add(tl, idx + 1 , acc.append( Add (path / idx, v)) )
81+ case Nil => acc
11082 }
11183
11284 // remove a bunch of array elements starting by the last one in the range
113- def remove (from : Int , until : Int , shift : Int , arr : List [Json ]): List [Operation [Json ]] =
114- (for (idx <- until to from by - 1 )
115- yield Remove [Json ](path / idx, if (rememberOld) Some (arr(idx - shift)) else None )).toList
85+ def remove (from : Int , until : Int , shift : Int , arr : List [Json ]): Chain [Operation [Json ]] =
86+ Chain .fromSeq(
87+ for (idx <- until to from by - 1 )
88+ yield Remove [Json ](path / idx, if (rememberOld) Some (arr(idx - shift)) else None ))
11689
11790 // now iterate over the first array to computes what was added, what was removed and what was modified
118- @ tailrec
11991 def loop (
12092 arr1 : List [Json ], // the first array
12193 arr2 : List [Json ], // the second array
12294 idx1 : Int , // current index in the first array
12395 shift1 : Int , // current index shift in the first array (due to elements being add or removed)
12496 idx2 : Int , // current index in the second array
12597 lcs : List [(Int , Int )], // the list of remaining matching indices
126- acc : List [Operation [Json ]] // the already accumulated result
127- ): List [ Operation [Json ]] = (arr1, arr2) match {
98+ acc : Chain [Operation [Json ]] // the already accumulated result
99+ ): Eval [ Chain [ Operation [Json ] ]] = (arr1, arr2) match {
128100 case (_ :: tl1, _) if isCommon1(idx1, lcs) =>
129101 // all values in arr2 were added until the index of common value
130102 val until = lcs.head._2
@@ -134,7 +106,7 @@ class JsonDiff[Json](diffArray: Boolean, rememberOld: Boolean)(implicit J: Jsony
134106 shift1 + until - idx2,
135107 until + 1 ,
136108 lcs.tail,
137- add(arr2.take(until - idx2), idx1 + shift1, Nil ) reverse_:: : acc )
109+ acc ++ add(arr2.take(until - idx2), idx1 + shift1, Chain .empty) )
138110 case (_, _ :: tl2) if isCommon2(idx2, lcs) =>
139111 // all values in arr1 were removed until the index of common value
140112 val until = lcs.head._1
@@ -144,18 +116,18 @@ class JsonDiff[Json](diffArray: Boolean, rememberOld: Boolean)(implicit J: Jsony
144116 shift1 - (until - idx1),
145117 idx2 + 1 ,
146118 lcs.tail,
147- remove(idx1 + shift1, until - 1 + shift1, idx1 + shift1, arr1) reverse_:: : acc )
119+ acc ++ remove(idx1 + shift1, until - 1 + shift1, idx1 + shift1, arr1))
148120 case (v1 :: tl1, v2 :: tl2) =>
149121 // values are different, recursively compute the diff of these values
150- loop(tl1, tl2, idx1 + 1 , shift1, idx2 + 1 , lcs, diff(v1, v2, path / (idx1 + shift1)) reverse_:: : acc )
122+ diff(v1, v2, path / (idx1 + shift1)).flatMap(d => loop(tl1, tl2, idx1 + 1 , shift1, idx2 + 1 , lcs, acc ++ d) )
151123 case (_, Nil ) =>
152124 // all subsequent values in arr1 were removed
153- remove(idx1 + shift1, idx1 + arr1.size - 1 + shift1, idx1 + shift1, arr1) reverse_:: : acc
125+ Eval .now(acc ++ remove(idx1 + shift1, idx1 + arr1.size - 1 + shift1, idx1 + shift1, arr1))
154126 case (Nil , _) =>
155127 // all subsequent value in arr2 were added
156- arr2.map(Add (path / " -" reverse_:: : acc
128+ Eval .now(acc ++ Chain .fromSeq( arr2.map(Add (path / " -" ))
157129 }
158130
159- loop(arr1, arr2, 0 , 0 , 0 , lcs, Nil ).reverse
131+ loop(arr1, arr2, 0 , 0 , 0 , lcs, Chain .empty)
160132 }
161133}
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