static JsonDocumentBuilder _FromDiff(JsonElement source, JsonElement target)
{
JsonElementEqualityComparer comparer = JsonElementEqualityComparer.Instance;
if (source.ValueKind != JsonValueKind.Object || target.ValueKind != JsonValueKind.Object)
{
return(new JsonDocumentBuilder(target));
}
var builder = new JsonDocumentBuilder(JsonValueKind.Object);
foreach (var property in source.EnumerateObject())
{
JsonElement value;
if (target.TryGetProperty(property.Name, out value))
{
if (!comparer.Equals(property.Value, value))
{
builder.AddProperty(property.Name, _FromDiff(property.Value, value));
}
}
else
{
builder.AddProperty(property.Name, new JsonDocumentBuilder(JsonValueKind.Null));
}
}
foreach (var property in target.EnumerateObject())
{
JsonElement value;
if (!source.TryGetProperty(property.Name, out value))
{
builder.AddProperty(property.Name, new JsonDocumentBuilder(property.Value));
}
}
return(builder);
}
static JsonDocumentBuilder _FromDiff(JsonElement source,
JsonElement target,
string path)
{
var builder = new JsonDocumentBuilder(JsonValueKind.Array);
JsonElementEqualityComparer comparer = JsonElementEqualityComparer.Instance;
if (comparer.Equals(source, target))
{
return(builder);
}
if (source.ValueKind == JsonValueKind.Array && target.ValueKind == JsonValueKind.Array)
{
int common = Math.Min(source.GetArrayLength(), target.GetArrayLength());
for (int i = 0; i < common; ++i)
{
var buffer = new StringBuilder(path);
buffer.Append("/");
buffer.Append(i.ToString());
var temp_diff = _FromDiff(source[i], target[i], buffer.ToString());
foreach (var item in temp_diff.EnumerateArray())
{
builder.AddArrayItem(item);
}
}
// Element in source, not in target - remove
for (int i = source.GetArrayLength(); i-- > target.GetArrayLength();)
{
var buffer = new StringBuilder(path);
buffer.Append("/");
buffer.Append(i.ToString());
var valBuilder = new JsonDocumentBuilder(JsonValueKind.Object);
valBuilder.AddProperty("op", new JsonDocumentBuilder("remove"));
valBuilder.AddProperty("path", new JsonDocumentBuilder(buffer.ToString()));
builder.AddArrayItem(valBuilder);
}
// Element in target, not in source - add,
for (int i = source.GetArrayLength(); i < target.GetArrayLength(); ++i)
{
var a = target[i];
var buffer = new StringBuilder(path);
buffer.Append("/");
buffer.Append(i.ToString());
var valBuilder = new JsonDocumentBuilder(JsonValueKind.Object);
valBuilder.AddProperty("op", new JsonDocumentBuilder("add"));
valBuilder.AddProperty("path", new JsonDocumentBuilder(buffer.ToString()));
valBuilder.AddProperty("value", new JsonDocumentBuilder(a));
builder.AddArrayItem(valBuilder);
}
}
else if (source.ValueKind == JsonValueKind.Object && target.ValueKind == JsonValueKind.Object)
{
foreach (var a in source.EnumerateObject())
{
var buffer = new StringBuilder(path);
buffer.Append("/");
buffer.Append(JsonPointer.Escape(a.Name));
JsonElement element;
if (target.TryGetProperty(a.Name, out element))
{
var temp_diff = _FromDiff(a.Value, element, buffer.ToString());
foreach (var item in temp_diff.EnumerateArray())
{
builder.AddArrayItem(item);
}
}
else
{
var valBuilder = new JsonDocumentBuilder(JsonValueKind.Object);
valBuilder.AddProperty("op", new JsonDocumentBuilder("remove"));
valBuilder.AddProperty("path", new JsonDocumentBuilder(buffer.ToString()));
builder.AddArrayItem(valBuilder);
}
}
foreach (var a in target.EnumerateObject())
{
JsonElement element;
if (!source.TryGetProperty(a.Name, out element))
{
var buffer = new StringBuilder(path);
buffer.Append("/");
buffer.Append(JsonPointer.Escape(a.Name));
var valBuilder = new JsonDocumentBuilder(JsonValueKind.Object);
valBuilder.AddProperty("op", new JsonDocumentBuilder("add"));
valBuilder.AddProperty("path", new JsonDocumentBuilder(buffer.ToString()));
valBuilder.AddProperty("value", new JsonDocumentBuilder(a.Value));
builder.AddArrayItem(valBuilder);
}
}
}
else
{
var valBuilder = new JsonDocumentBuilder(JsonValueKind.Object);
valBuilder.AddProperty("op", new JsonDocumentBuilder("replace"));
valBuilder.AddProperty("path", new JsonDocumentBuilder(path));
valBuilder.AddProperty("value", new JsonDocumentBuilder(target));
builder.AddArrayItem(valBuilder);
}
return(builder);
}
static void ApplyPatch(ref JsonDocumentBuilder target,
JsonElement patch)
{
JsonElementEqualityComparer comparer = JsonElementEqualityComparer.Instance;
Debug.Assert(target != null);
if (patch.ValueKind != JsonValueKind.Array)
{
throw new ArgumentException("Patch must be an array");
}
foreach (var operation in patch.EnumerateArray())
{
JsonElement opElement;
if (!operation.TryGetProperty("op", out opElement))
{
throw new ArgumentException("Invalid patch");
}
string op = opElement.GetString() ?? throw new InvalidOperationException("Operation cannot be null");
JsonElement pathElement;
if (!operation.TryGetProperty("path", out pathElement))
{
throw new ArgumentException(op, "Invalid patch");
}
string path = pathElement.GetString() ?? throw new InvalidOperationException("Operation cannot be null");;
JsonPointer location;
if (!JsonPointer.TryParse(path, out location))
{
throw new ArgumentException(op, "Invalid patch");
}
if (op == "test")
{
JsonElement value;
if (!operation.TryGetProperty("value", out value))
{
throw new ArgumentException(op, "Invalid patch");
}
JsonDocumentBuilder tested;
if (!location.TryGetValue(target, out tested))
{
throw new ArgumentException(op, "Invalid patch");
}
using (var doc = tested.ToJsonDocument())
{
if (!comparer.Equals(doc.RootElement, value))
{
throw new JsonPatchException(op, "Test failed");
}
}
}
else if (op == "add")
{
JsonElement value;
if (!operation.TryGetProperty("value", out value))
{
throw new ArgumentException(op, "Invalid patch");
}
var valueBuilder = new JsonDocumentBuilder(value);
if (!location.TryAddIfAbsent(ref target, valueBuilder)) // try insert without replace
{
if (!location.TryReplace(ref target, valueBuilder)) // try insert without replace
{
throw new JsonPatchException(op, "Add failed");
}
}
}
else if (op == "remove")
{
if (!location.TryRemove(ref target))
{
throw new JsonPatchException(op, "Add failed");
}
}
else if (op == "replace")
{
JsonElement value;
if (!operation.TryGetProperty("value", out value))
{
throw new ArgumentException(op, "Invalid patch");
}
var valueBuilder = new JsonDocumentBuilder(value);
if (!location.TryReplace(ref target, valueBuilder))
{
throw new JsonPatchException(op, "Replace failed");
}
}
else if (op == "move")
{
JsonElement fromElement;
if (!operation.TryGetProperty("from", out fromElement))
{
throw new ArgumentException(op, "Invalid patch");
}
string from = fromElement.GetString() ?? throw new InvalidOperationException("From element cannot be null");;
JsonPointer fromPointer;
if (!JsonPointer.TryParse(from, out fromPointer))
{
throw new ArgumentException(op, "Invalid patch");
}
JsonDocumentBuilder value;
if (!fromPointer.TryGetValue(target, out value))
{
throw new JsonPatchException(op, "Move failed");
}
if (!fromPointer.TryRemove(ref target))
{
throw new JsonPatchException(op, "Move failed");
}
if (!location.TryAddIfAbsent(ref target, value))
{
if (!location.TryReplace(ref target, value)) // try insert without replace
{
throw new JsonPatchException(op, "Move failed");
}
}
}
else if (op == "copy")
{
JsonElement fromElement;
if (!operation.TryGetProperty("from", out fromElement))
{
throw new ArgumentException(op, "Invalid patch");
}
string from = fromElement.GetString() ?? throw new InvalidOperationException("from cannot be null");
JsonPointer fromPointer;
if (!JsonPointer.TryParse(from, out fromPointer))
{
throw new ArgumentException(op, "Invalid patch");
}
JsonDocumentBuilder value;
if (!fromPointer.TryGetValue(target, out value))
{
throw new JsonPatchException(op, "Copy failed");
}
if (!location.TryAddIfAbsent(ref target, value))
{
if (!location.TryReplace(ref target, value)) // try insert without replace
{
throw new JsonPatchException(op, "Move failed");
}
}
}
}
}
