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jsondiffpatch.net
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[add] item match serves object hash

pull/48/head
khiemnd777 2018-10-05 11:49:32 +07:00
parent 6492f22795
commit 5e2808445a
7 changed files with 262 additions and 141 deletions
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22
Src/JsonDiffPatchDotNet.UnitTests/DiffUnitTests.cs
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@ -224,9 +224,9 @@ namespace JsonDiffPatchDotNet.UnitTests
[Test]
public void Diff_EfficientArrayDiffSameLengthNested_ValidDiff()
{
var jdp = new JsonDiffPatch(new Options { ArrayDiff = ArrayDiffMode.Efficient });
var left = JToken.Parse(@"[1,2,{""p"":false},4]");
var right = JToken.Parse(@"[1,2,{""p"":true},4]");
var jdp = new JsonDiffPatch(new Options { ArrayDiff = ArrayDiffMode.Efficient, ObjectHash = (jObj) => jObj["Id"].Value<string>() });
var left = JToken.Parse(@"[1,2,{""Id"" : ""F12B21EF-F57D-4958-ADDC-A3F52EC25EC8"", ""p"":false},4]");
var right = JToken.Parse(@"[1,2,{""Id"" : ""F12B21EF-F57D-4958-ADDC-A3F52EC25EC8"", ""p"":true},4]");
JObject diff = jdp.Diff(left, right) as JObject;
@ -235,7 +235,21 @@ namespace JsonDiffPatchDotNet.UnitTests
Assert.IsNotNull(diff["2"]);
}
[Test]
[Test]
public void Diff_EfficientArrayDiffWithComplexObject_ValidDiff()
{
var jdp = new JsonDiffPatch(new Options { ArrayDiff = ArrayDiffMode.Efficient, ObjectHash = (jObj) => jObj["Id"].Value<string>() });
//var jdp = new JsonDiffPatch(new Options { ArrayDiff = ArrayDiffMode.Efficient });
var left = JToken.Parse(@"[{""Id"" : ""F12B21EF-F57D-4958-ADDC-A3F52EC25EC8"", ""p"":false}, {""Id"" : ""F12B21EF-F57D-4958-ADDC-A3F52EC25EC9"", ""p"":true}]");
var right = JToken.Parse(@"[{""Id"" : ""F12B21EF-F57D-4958-ADDC-A3F52EC25EC8"", ""p"":true}, {""Id"" : ""F12B21EF-F57D-4958-ADDC-A3F52EC25EC10"", ""p"":false}]");
JObject diff = jdp.Diff(left, right) as JObject;
Assert.IsNotNull(diff);
Assert.AreEqual(4, diff.Properties().Count());
}
[Test]
public void Diff_EfficientArrayDiffSameWithObject_NoDiff()
{
var jdp = new JsonDiffPatch(new Options { ArrayDiff = ArrayDiffMode.Efficient });

2
Src/JsonDiffPatchDotNet/ArrayDiffMode.cs
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@ -16,6 +16,6 @@
/// the entire left and entire right arrays are added to the patch document as a simple
/// JSON token replace. If they are the same, then token is skipped in the patch document.
/// </summary>
Simple,
Simple
}
}

17
Src/JsonDiffPatchDotNet/DefaultItemMatch.cs Normal file
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@ -0,0 +1,17 @@
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace JsonDiffPatchDotNet
{
public class DefaultItemMatch : ItemMatch
{
public DefaultItemMatch(Func<JToken, object> objectHash):base(objectHash)
{
}
}
}

49
Src/JsonDiffPatchDotNet/ItemMatch.cs Normal file
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@ -0,0 +1,49 @@
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace JsonDiffPatchDotNet
{
public abstract class ItemMatch
{
internal Func<JToken, object> ObjectHash;
protected ItemMatch()
{
}
protected ItemMatch(Func<JToken, object> objectHash)
{
ObjectHash = objectHash;
}
public virtual bool Match(JToken object1, JToken object2)
{
return Match(object1, object2, ObjectHash);
}
public virtual bool Match(JToken object1, JToken object2, Func<JToken, object> objectHash)
{
if(objectHash == null || object1.Type != JTokenType.Object)
{
return JToken.DeepEquals(object1, object2);
}
var hash1 = objectHash.Invoke(object1);
if(hash1 == null)
{
return false;
}
var hash2 = objectHash.Invoke(object2);
if(hash2 == null)
{
return false;
}
return hash1.Equals(hash2);
}
}
}

174
Src/JsonDiffPatchDotNet/JsonDiffPatch.cs
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@ -37,6 +37,9 @@ namespace JsonDiffPatchDotNet
/// <returns>JSON Patch Document</returns>
public JToken Diff(JToken left, JToken right)
{
var objectHash = this._options.ObjectHash;
var itemMatch = new DefaultItemMatch(objectHash);
if (left == null)
left = new JValue("");
if (right == null)
@ -66,7 +69,7 @@ namespace JsonDiffPatchDotNet
: null;
}
if (!JToken.DeepEquals(left, right))
if (!itemMatch.Match(left, right))
return new JArray(left, right);
return null;
@ -356,92 +359,117 @@ namespace JsonDiffPatchDotNet
return null;
}
private JObject ArrayDiff(JArray left, JArray right)
{
var result = JObject.Parse(@"{ ""_t"": ""a"" }");
private JObject ArrayDiff(JArray left, JArray right)
{
var objectHash = this._options.ObjectHash;
var itemMatch = new DefaultItemMatch(objectHash);
var result = JObject.Parse(@"{ ""_t"": ""a"" }");
int commonHead = 0;
int commonTail = 0;
int commonHead = 0;
int commonTail = 0;
if (JToken.DeepEquals(left, right))
return null;
if (itemMatch.Match(left, right))
return null;
// Find common head
while (commonHead < left.Count
&& commonHead < right.Count
&& JToken.DeepEquals(left[commonHead], right[commonHead]))
{
commonHead++;
}
var childContext = new List<JToken>();
// Find common tail
while (commonTail + commonHead < left.Count
&& commonTail + commonHead < right.Count
&& JToken.DeepEquals(left[left.Count - 1 - commonTail], right[right.Count - 1 - commonTail]))
{
commonTail++;
}
// Find common head
while (commonHead < left.Count
&& commonHead < right.Count
&& itemMatch.Match(left[commonHead], right[commonHead]))
{
var index = commonHead;
var child = Diff(left[index], right[index]);
if(child != null)
{
result[$"{index}"] = child;
}
commonHead++;
}
if (commonHead + commonTail == left.Count)
{
// Trivial case, a block (1 or more consecutive items) was added
for (int index = commonHead; index < right.Count - commonTail; ++index)
{
result[$"{index}"] = new JArray(right[index]);
}
// Find common tail
while (commonTail + commonHead < left.Count
&& commonTail + commonHead < right.Count
&& itemMatch.Match(left[left.Count - 1 - commonTail], right[right.Count - 1 - commonTail]))
{
var index1 = left.Count - 1 - commonTail;
var index2 = right.Count - 1 - commonTail;
var child = Diff(left[index1], right[index2]);
if(child != null)
{
result[$"{index2}"] = child;
}
commonTail++;
}
return result;
}
if (commonHead + commonTail == right.Count)
{
// Trivial case, a block (1 or more consecutive items) was removed
for (int index = commonHead; index < left.Count - commonTail; ++index)
{
result[$"_{index}"] = new JArray(left[index], 0, (int)DiffOperation.Deleted);
}
if (commonHead + commonTail == left.Count)
{
// Trivial case, a block (1 or more consecutive items) was added
for (int index = commonHead; index < right.Count - commonTail; ++index)
{
result[$"{index}"] = new JArray(right[index]);
}
return result;
}
return result;
}
if (commonHead + commonTail == right.Count)
{
// Trivial case, a block (1 or more consecutive items) was removed
for (int index = commonHead; index < left.Count - commonTail; ++index)
{
if (result.ContainsKey(index.ToString()))
{
result.Remove(index.ToString());
}
result[$"_{index}"] = new JArray(left[index], 0, (int)DiffOperation.Deleted);
}
// Complex Diff, find the LCS (Longest Common Subsequence)
List<JToken> trimmedLeft = left.ToList().GetRange(commonHead, left.Count - commonTail - commonHead);
List<JToken> trimmedRight = right.ToList().GetRange(commonHead, right.Count - commonTail - commonHead);
Lcs lcs = Lcs.Get(trimmedLeft, trimmedRight);
return result;
}
for (int index = commonHead; index < left.Count - commonTail; ++index)
{
if (lcs.Indices1.IndexOf(index - commonHead) < 0)
{
// Removed
result[$"_{index}"] = new JArray(left[index], 0, (int)DiffOperation.Deleted);
}
}
// Complex Diff, find the LCS (Longest Common Subsequence)
List<JToken> trimmedLeft = left.ToList().GetRange(commonHead, left.Count - commonTail - commonHead);
List<JToken> trimmedRight = right.ToList().GetRange(commonHead, right.Count - commonTail - commonHead);
Lcs lcs = Lcs.Get(trimmedLeft, trimmedRight, itemMatch);
for (int index = commonHead; index < right.Count - commonTail; index++)
{
int indexRight = lcs.Indices2.IndexOf(index - commonHead);
for (int index = commonHead; index < left.Count - commonTail; ++index)
{
if (lcs.Indices1.IndexOf(index - commonHead) < 0)
{
// Removed
if (result.ContainsKey(index.ToString()))
{
result.Remove(index.ToString());
}
result[$"_{index}"] = new JArray(left[index], 0, (int)DiffOperation.Deleted);
}
}
if (indexRight < 0)
{
// Added
result[$"{index}"] = new JArray(right[index]);
}
else
{
int li = lcs.Indices1[indexRight] + commonHead;
int ri = lcs.Indices2[indexRight] + commonHead;
for (int index = commonHead; index < right.Count - commonTail; index++)
{
int indexRight = lcs.Indices2.IndexOf(index - commonHead);
JToken diff = Diff(left[li], right[ri]);
if (indexRight < 0)
{
// Added
result[$"{index}"] = new JArray(right[index]);
}
else
{
int li = lcs.Indices1[indexRight] + commonHead;
int ri = lcs.Indices2[indexRight] + commonHead;
if (diff != null)
{
result[$"{index}"] = diff;
}
}
}
JToken diff = Diff(left[li], right[ri]);
return result;
}
if (diff != null)
{
result[$"{index}"] = diff;
}
}
}
return result;
}
private JObject ObjectPatch(JObject obj, JObject patch)
{

78
Src/JsonDiffPatchDotNet/Lcs.cs
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@ -4,51 +4,51 @@ using Newtonsoft.Json.Linq;
namespace JsonDiffPatchDotNet
{
internal class Lcs
{
internal List<JToken> Sequence { get; set; }
internal class Lcs
{
internal List<JToken> Sequence { get; set; }
internal List<int> Indices1 { get; set; }
internal List<int> Indices1 { get; set; }
internal List<int> Indices2 { get; set; }
internal List<int> Indices2 { get; set; }
private Lcs()
{
Sequence = new List<JToken>();
Indices1 = new List<int>();
Indices2 = new List<int>();
}
private Lcs()
{
Sequence = new List<JToken>();
Indices1 = new List<int>();
Indices2 = new List<int>();
}
internal static Lcs Get(List<JToken> left, List<JToken> right)
{
var matrix = LcsInternal(left, right);
var result = Backtrack(matrix, left, right, left.Count, right.Count);
return result;
}
internal static Lcs Get(List<JToken> left, List<JToken> right, ItemMatch match)
{
var matrix = LcsInternal(left, right, match);
var result = Backtrack(matrix, left, right, left.Count, right.Count, match);
return result;
}
private static int[,] LcsInternal(List<JToken> left, List<JToken> right)
{
var arr = new int[left.Count + 1, right.Count + 1];
private static int[,] LcsInternal(List<JToken> left, List<JToken> right, ItemMatch match)
{
var arr = new int[left.Count + 1, right.Count + 1];
for (int i = 1; i <= left.Count; i++)
{
for (int j = 1; j <= right.Count; j++)
{
if (JToken.DeepEquals(left[i - 1], right[j - 1]))
{
arr[i, j] = arr[i - 1, j - 1] + 1;
}
else
{
arr[i, j] = Math.Max(arr[i - 1, j], arr[i, j - 1]);
}
}
}
for (int i = 1; i <= left.Count; i++)
{
for (int j = 1; j <= right.Count; j++)
{
if (match.Match(left[i - 1], right[j - 1]))
{
arr[i, j] = arr[i - 1, j - 1] + 1;
}
else
{
arr[i, j] = Math.Max(arr[i - 1, j], arr[i, j - 1]);
}
}
}
return arr;
}
return arr;
}
private static Lcs Backtrack(int[,] matrix, List<JToken> left, List<JToken> right, int li, int ri)
private static Lcs Backtrack(int[,] matrix, List<JToken> left, List<JToken> right, int li, int ri, ItemMatch match)
{
var result = new Lcs();
for (int i = 1, j = 1; i <= li && j <= ri;)
@ -56,9 +56,7 @@ namespace JsonDiffPatchDotNet
// If the JSON tokens at the same position are both Objects or both Arrays, we just say they
// are the same even if they are not, because we can package smaller deltas than an entire
// object or array replacement by doing object to object or array to array diff.
if (JToken.DeepEquals(left[i - 1], right[j - 1])
|| left[i - 1].Type == JTokenType.Object && right[j - 1].Type == JTokenType.Object
|| left[i - 1].Type == JTokenType.Array && right[j - 1].Type == JTokenType.Array)
if (match.Match(left[i - 1], right[j - 1]))
{
result.Sequence.Add(left[i - 1]);
result.Indices1.Add(i - 1);

61
Src/JsonDiffPatchDotNet/Options.cs
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@ -1,28 +1,43 @@
namespace JsonDiffPatchDotNet
using System;
using Newtonsoft.Json.Linq;
namespace JsonDiffPatchDotNet
{
public sealed class Options
{
public Options()
{
ArrayDiff = ArrayDiffMode.Efficient;
TextDiff = TextDiffMode.Efficient;
MinEfficientTextDiffLength = 50;
}
public sealed class Options
{
public Options()
{
ArrayDiff = ArrayDiffMode.Efficient;
TextDiff = TextDiffMode.Efficient;
MinEfficientTextDiffLength = 50;
}
/// <summary>
/// Specifies how arrays are diffed. The default is Simple.
/// </summary>
public ArrayDiffMode ArrayDiff { get; set; }
/// <summary>
/// Specifies how arrays are diffed. The default is Simple.
/// </summary>
public ArrayDiffMode ArrayDiff { get; set; }
/// <summary>
/// Specifies how string values are diffed. The default is Efficient.
/// </summary>
public TextDiffMode TextDiff { get; set; }
/// <summary>
/// Specifies how string values are diffed. The default is Efficient.
/// </summary>
public TextDiffMode TextDiff { get; set; }
/// <summary>
/// The minimum string length required to use Efficient text diff. If the minimum
/// length is not met, simple text diff will be used. The default length is 50 characters.
/// </summary>
public long MinEfficientTextDiffLength { get; set; }
}
/// <summary>
/// The minimum string length required to use Efficient text diff. If the minimum
/// length is not met, simple text diff will be used. The default length is 50 characters.
/// </summary>
public long MinEfficientTextDiffLength { get; set; }
/// <summary>
/// for LCS to work, it needs a way to match items between previous/original (or left/right) arrays. In traditional text diff tools this is trivial, as two lines of text are compared char
/// char.
/// When no matches by reference or value are found, array diffing fallbacks to a dumb behavior: matching items by position.
/// Matching by position is not the most efficient option (eg. if an item is added at the first position, all the items below will be considered modified), but it produces expected results
/// in most trivial cases.This is good enough as soon as movements/insertions/deletions only happen near the bottom of the array.
/// This is because if 2 objects are not equal by reference(ie.the same object) both objects are considered different values, as there is no trivial solution to compare two arbitrary objects
/// in JavaScript.
/// To improve the results leveraging the power of LCS(and position move detection) you need to provide a way to compare 2 objects.
/// </summary>
public Func<JToken, object> ObjectHash { get; set; }
}
}