ARROW-5112: [Go] implement writing IPC Arrow stream/file

go/arrow/array/binary.go

@@ -17,6 +17,8 @@
 package array
 
 import (
+	"fmt"
+	"strings"
 	"unsafe"
 
 	"github.com/apache/arrow/go/arrow"
@@ -80,6 +82,24 @@ func (a *Binary) ValueBytes() []byte {
 	return a.valueBytes[a.valueOffsets[beg]:a.valueOffsets[end]]
 }
 
+func (a *Binary) String() string {
+	o := new(strings.Builder)
+	o.WriteString("[")
+	for i := 0; i < a.Len(); i++ {
+		if i > 0 {
+			o.WriteString(" ")
+		}
+		switch {
+		case a.IsNull(i):
+			o.WriteString("(null)")
+		default:
+			fmt.Fprintf(o, "%q", a.ValueString(i))
+		}
+	}
+	o.WriteString("]")
+	return o.String()
+}
+
 func (a *Binary) setData(data *Data) {
 	if len(data.buffers) != 3 {
 		panic("len(data.buffers) != 3")

go/arrow/array/binary_test.go

@@ -405,3 +405,26 @@ func TestBinaryValueBytes(t *testing.T) {
 
 	assert.Equal(t, []byte{'h', 'i', 'j', 'k', 'l', 'm', 'o', 'p', 'q'}, slice.ValueBytes())
 }
+
+func TestBinaryStringer(t *testing.T) {
+	mem := memory.NewCheckedAllocator(memory.NewGoAllocator())
+	defer mem.AssertSize(t, 0)
+
+	values := []string{"a", "bc", "", "é", "", "hijk", "lm", "", "opq", "", "tu"}
+	valids := []bool{true, true, false, true, false, true, true, true, true, false, true}
+
+	b := NewBinaryBuilder(mem, arrow.BinaryTypes.Binary)
+	defer b.Release()
+
+	b.AppendStringValues(values, valids)
+
+	arr := b.NewArray().(*Binary)
+	defer arr.Release()
+
+	got := arr.String()
+	want := `["a" "bc" (null) "é" (null) "hijk" "lm" "" "opq" (null) "tu"]`
+
+	if got != want {
+		t.Fatalf("invalid stringer:\ngot= %s\nwant=%s\n", got, want)
+	}
+}

go/arrow/array/list.go

@@ -79,6 +79,11 @@ func (a *List) Len() int { return a.array.Len() }
 
 func (a *List) Offsets() []int32 { return a.offsets }
 
+func (a *List) Retain() {
+	a.array.Retain()
+	a.values.Retain()
+}
+
 func (a *List) Release() {
 	a.array.Release()
 	a.values.Release()

go/arrow/array/list_test.go

@@ -55,6 +55,9 @@ func TestListArray(t *testing.T) {
 		arr := lb.NewArray().(*array.List)
 		defer arr.Release()
 
+		arr.Retain()
+		arr.Release()
+
 		if got, want := arr.DataType().ID(), arrow.LIST; got != want {
 			t.Fatalf("got=%v, want=%v", got, want)
 		}

go/arrow/array/string.go

@@ -46,7 +46,8 @@ func NewStringData(data *Data) *String {
 }
 
 // Value returns the slice at index i. This value should not be mutated.
-func (a *String) Value(i int) string { return a.values[a.offsets[i]:a.offsets[i+1]] }
+func (a *String) Value(i int) string    { return a.values[a.offsets[i]:a.offsets[i+1]] }
+func (a *String) ValueOffset(i int) int { return int(a.offsets[i]) }
 
 func (a *String) String() string {
 	o := new(strings.Builder)

go/arrow/array/string_test.go

@@ -30,8 +30,9 @@ func TestStringArray(t *testing.T) {
 	defer mem.AssertSize(t, 0)
 
 	var (
-		want   = []string{"hello", "世界", "", "bye"}
-		valids = []bool{true, true, false, true}
+		want    = []string{"hello", "世界", "", "bye"}
+		valids  = []bool{true, true, false, true}
+		offsets = []int{0, 5, 11, 11, 14}
 	)
 
 	sb := array.NewStringBuilder(mem)
@@ -79,6 +80,13 @@ func TestStringArray(t *testing.T) {
 				t.Fatalf("arr[%d]: got=%q, want=%q", i, got, want[i])
 			}
 		}
+
+		if got, want := arr.ValueOffset(i), offsets[i]; got != want {
+			t.Fatalf("arr-offset-beg[%d]: got=%d, want=%d", i, got, want)
+		}
+		if got, want := arr.ValueOffset(i+1), offsets[i+1]; got != want {
+			t.Fatalf("arr-offset-end[%d]: got=%d, want=%d", i+1, got, want)
+		}
 	}
 
 	sub := array.MakeFromData(arr.Data())

go/arrow/array/struct.go

@@ -65,6 +65,13 @@ func (a *Struct) setData(data *Data) {
 	}
 }
 
+func (a *Struct) Retain() {
+	a.array.Retain()
+	for _, f := range a.fields {
+		f.Retain()
+	}
+}
+
 func (a *Struct) Release() {
 	a.array.Release()
 	for _, f := range a.fields {

go/arrow/array/struct_test.go

@@ -79,6 +79,9 @@ func TestStructArray(t *testing.T) {
 		arr := sb.NewArray().(*array.Struct)
 		defer arr.Release()
 
+		arr.Retain()
+		arr.Release()
+
 		if got, want := arr.DataType().ID(), arrow.STRUCT; got != want {
 			t.Fatalf("got=%v, want=%v", got, want)
 		}