Slightly more efficient conversion from JSON to document

database/table.go

@@ -514,7 +514,7 @@ func validateConstraint(d document.Document, c *FieldConstraint) error {
 		}
 	case document.ArrayValue:
 		// if it's an array, we can assume it's a ValueBuffer
-		buf := parent.V.(*document.ValueBuffer)
+		buf := parent.V.(document.ValueBuffer)
 
 		frag := c.Path[len(c.Path)-1]
 		if frag.FieldName != "" {

document/array.go

@@ -68,6 +68,11 @@ type ValueBuffer []Value
 
 // NewValueBuffer creates a buffer of values.
 func NewValueBuffer(values ...Value) ValueBuffer {
+	if len(values) == 0 {
+		// If called with no values return a non-nil slice.
+		return ValueBuffer{}
+	}
+
 	return ValueBuffer(values)
 }
 
@@ -141,7 +146,7 @@ func (vb *ValueBuffer) Copy(a Array) error {
 				return err
 			}
 
-			err = vb.Replace(i, NewArrayValue(&buf))
+			err = vb.Replace(i, NewArrayValue(buf))
 			if err != nil {
 				return err
 			}

document/create.go

@@ -9,16 +9,43 @@ import (
 	"reflect"
 	"strings"
 	"time"
+
+	"github.com/buger/jsonparser"
 )
 
-// NewFromJSON creates a document from a JSON object.
-func NewFromJSON(data []byte) (Document, error) {
-	var fb FieldBuffer
-	err := fb.UnmarshalJSON(data)
+// NewFromJSON creates a document from raw JSON data.
+// The returned document will lazily decode the data.
+// If data is not a valid json object, calls to Iterate or GetByField will
+// return an error.
+func NewFromJSON(data []byte) Document {
+	return &jsonEncodedDocument{data}
+}
+
+type jsonEncodedDocument struct {
+	data []byte
+}
+
+func (j jsonEncodedDocument) Iterate(fn func(field string, value Value) error) error {
+	return jsonparser.ObjectEach(j.data, func(key, value []byte, dataType jsonparser.ValueType, offset int) error {
+		v, err := parseJSONValue(dataType, value)
+		if err != nil {
+			return err
+		}
+
+		return fn(string(key), v)
+	})
+}
+
+func (j jsonEncodedDocument) GetByField(field string) (Value, error) {
+	v, dt, _, err := jsonparser.Get(j.data, field)
+	if dt == jsonparser.NotExist {
+		return Value{}, ErrFieldNotFound
+	}
 	if err != nil {
-		return nil, err
+		return Value{}, err
 	}
-	return &fb, nil
+
+	return parseJSONValue(dt, v)
 }
 
 // NewFromMap creates a document from a map.

document/create_test.go

@@ -0,0 +1,86 @@
+package document_test
+
+import (
+	"testing"
+
+	"github.com/genjidb/genji/document"
+	"github.com/stretchr/testify/require"
+)
+
+func TestNewFromJSON(t *testing.T) {
+	tests := []struct {
+		name     string
+		data     string
+		expected *document.FieldBuffer
+		fails    bool
+	}{
+		{"empty object", "{}", document.NewFieldBuffer(), false},
+		{"empty object, missing closing bracket", "{", nil, true},
+		{"classic object", `{"a": 1, "b": true, "c": "hello", "d": [1, 2, 3], "e": {"f": "g"}}`,
+			document.NewFieldBuffer().
+				Add("a", document.NewIntegerValue(1)).
+				Add("b", document.NewBoolValue(true)).
+				Add("c", document.NewTextValue("hello")).
+				Add("d", document.NewArrayValue(document.NewValueBuffer().
+					Append(document.NewIntegerValue(1)).
+					Append(document.NewIntegerValue(2)).
+					Append(document.NewIntegerValue(3)))).
+				Add("e", document.NewDocumentValue(document.NewFieldBuffer().Add("f", document.NewTextValue("g")))),
+			false},
+		{"string values", `{"a": "hello ciao"}`, document.NewFieldBuffer().Add("a", document.NewTextValue("hello ciao")), false},
+		{"+integer values", `{"a": 1000}`, document.NewFieldBuffer().Add("a", document.NewIntegerValue(1000)), false},
+		{"-integer values", `{"a": -1000}`, document.NewFieldBuffer().Add("a", document.NewIntegerValue(-1000)), false},
+		{"+float values", `{"a": 10000000000.0}`, document.NewFieldBuffer().Add("a", document.NewDoubleValue(10000000000)), false},
+		{"-float values", `{"a": -10000000000.0}`, document.NewFieldBuffer().Add("a", document.NewDoubleValue(-10000000000)), false},
+		{"bool values", `{"a": true, "b": false}`, document.NewFieldBuffer().Add("a", document.NewBoolValue(true)).Add("b", document.NewBoolValue(false)), false},
+		{"empty arrays", `{"a": []}`, document.NewFieldBuffer().Add("a", document.NewArrayValue(document.NewValueBuffer())), false},
+		{"nested arrays", `{"a": [[1,  2]]}`, document.NewFieldBuffer().
+			Add("a", document.NewArrayValue(
+				document.NewValueBuffer().
+					Append(document.NewArrayValue(
+						document.NewValueBuffer().
+							Append(document.NewIntegerValue(1)).
+							Append(document.NewIntegerValue(2)))))), false},
+		{"missing comma", `{"a": 1 "b": 2}`, nil, true},
+		{"missing closing brackets", `{"a": 1, "b": 2`, nil, true},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			d := document.NewFromJSON([]byte(test.data))
+
+			fb := document.NewFieldBuffer()
+			err := fb.Copy(d)
+
+			if test.fails {
+				require.Error(t, err)
+			} else {
+				require.NoError(t, err)
+				require.Equal(t, *test.expected, *fb)
+			}
+		})
+	}
+
+	t.Run("GetByField", func(t *testing.T) {
+		d := document.NewFromJSON([]byte(`{"a": 1000}`))
+
+		v, err := d.GetByField("a")
+		require.NoError(t, err)
+		require.Equal(t, document.NewIntegerValue(1000), v)
+
+		v, err = d.GetByField("b")
+		require.Equal(t, document.ErrFieldNotFound, err)
+	})
+}
+
+func BenchmarkJSONToDocument(b *testing.B) {
+	data := []byte(`{"_id":"5f8aefb8e443c6c13afdb305","index":0,"guid":"42c2719e-3371-4b2f-b855-d302a8b7eab0","isActive":true,"balance":"$1,064.79","picture":"http://placehold.it/32x32","age":40,"eyeColor":"blue","name":"Adele Webb","gender":"female","company":"EXTRAGEN","email":"adelewebb@extragen.com","phone":"+1 (964) 409-2397","address":"970 Charles Place, Watrous, Texas, 2522","about":"Amet non do ullamco duis velit sunt esse et cillum nisi mollit ea magna. Tempor ut occaecat proident laborum velit nisi et excepteur exercitation non est labore. Laboris pariatur enim proident et. Qui minim enim et incididunt incididunt adipisicing tempor. Occaecat adipisicing sint ex ut exercitation exercitation voluptate. Laboris adipisicing ut cillum eu cillum est sunt amet Lorem quis pariatur.\r\n","registered":"2016-05-25T10:36:44 -04:00","latitude":64.57112,"longitude":176.136138,"tags":["velit","minim","eiusmod","est","eu","voluptate","deserunt"],"friends":[{"id":0,"name":"Mathis Robertson"},{"id":1,"name":"Cecilia Donaldson"},{"id":2,"name":"Joann Goodwin"}],"greeting":"Hello, Adele Webb! You have 2 unread messages.","favoriteFruit":"apple"}`)
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		d := document.NewFromJSON(data)
+		d.Iterate(func(string, document.Value) error {
+			return nil
+		})
+	}
+}

document/document.go

@@ -290,7 +290,7 @@ func (fb *FieldBuffer) Copy(d Document) error {
 				return err
 			}
 
-			fb.fields[i].Value = NewArrayValue(&buf)
+			fb.fields[i].Value = NewArrayValue(buf)
 		}
 	}
 

document/document_test.go

@@ -83,7 +83,6 @@ func TestFieldBuffer(t *testing.T) {
 	})
 
 	t.Run("Set", func(t *testing.T) {
-
 		tests := []struct {
 			name  string
 			data  string
@@ -118,9 +117,8 @@ func TestFieldBuffer(t *testing.T) {
 			t.Run(tt.name, func(t *testing.T) {
 				var fb document.FieldBuffer
 
-				d, err := document.NewFromJSON([]byte(tt.data))
-				require.NoError(t, err)
-				err = fb.Copy(d)
+				d := document.NewFromJSON([]byte(tt.data))
+				err := fb.Copy(d)
 				require.NoError(t, err)
 				p, err := parser.ParsePath(tt.path)
 				require.NoError(t, err)

sql/query/expr/expr_test.go

@@ -13,13 +13,11 @@ import (
 )
 
 var doc document.Document = func() document.Document {
-	d, _ := document.NewFromJSON([]byte(`{
+	return document.NewFromJSON([]byte(`{
 		"a": 1,
 		"b": {"foo bar": [1, 2]},
 		"c": [1, {"foo": "bar"}, [1, 2]]
 	}`))
-
-	return d
 }()
 
 var stackWithDoc = expr.EvalStack{

sql/query/expr/path_test.go

@@ -1,6 +1,7 @@
 package expr_test
 
 import (
+	"encoding/json"
 	"testing"
 
 	"github.com/genjidb/genji/document"
@@ -16,8 +17,10 @@ func TestPathExpr(t *testing.T) {
 	}{
 		{"a", document.NewIntegerValue(1), false},
 		{"b", func() document.Value {
-			d, _ := document.NewFromJSON([]byte(`{"foo bar": [1, 2]}`))
-			return document.NewDocumentValue(d)
+			fb := document.NewFieldBuffer()
+			err := json.Unmarshal([]byte(`{"foo bar": [1, 2]}`), fb)
+			require.NoError(t, err)
+			return document.NewDocumentValue(fb)
 		}(),
 			false},
 		{"b.`foo bar`[0]", document.NewIntegerValue(1), false},
@@ -30,12 +33,11 @@ func TestPathExpr(t *testing.T) {
 		{"d", nullLitteral, false},
 	}
 
-	d, err := document.NewFromJSON([]byte(`{
+	d := document.NewFromJSON([]byte(`{
 		"a": 1,
 		"b": {"foo bar": [1, 2]},
 		"c": [1, {"foo": "bar"}, [1, 2]]
 	}`))
-	require.NoError(t, err)
 
 	for _, test := range tests {
 		t.Run(test.expr, func(t *testing.T) {