Port 'docker images' to the engine API

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)

engine/env.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"sort"
 	"strconv"
 	"strings"
 )
@@ -232,3 +233,76 @@ func (env *Env) Map() map[string]string {
 	}
 	return m
 }
+
+type Table struct {
+	Data    []*Env
+	sortKey string
+}
+
+func NewTable(sortKey string, sizeHint int) *Table {
+	return &Table{
+		make([]*Env, 0, sizeHint),
+		sortKey,
+	}
+}
+
+func (t *Table) Add(env *Env) {
+	t.Data = append(t.Data, env)
+}
+
+func (t *Table) Len() int {
+	return len(t.Data)
+}
+
+func (t *Table) Less(a, b int) bool {
+	return t.lessBy(a, b, t.sortKey)
+}
+
+func (t *Table) lessBy(a, b int, by string) bool {
+	keyA := t.Data[a].Get(by)
+	keyB := t.Data[b].Get(by)
+	intA, errA := strconv.ParseInt(keyA, 10, 64)
+	intB, errB := strconv.ParseInt(keyB, 10, 64)
+	if errA == nil && errB == nil {
+		return intA < intB
+	}
+	return keyA < keyB
+}
+
+func (t *Table) Swap(a, b int) {
+	tmp := t.Data[a]
+	t.Data[a] = t.Data[b]
+	t.Data[b] = tmp
+}
+
+func (t *Table) Sort() {
+	sort.Sort(t)
+}
+
+func (t *Table) WriteTo(dst io.Writer) (n int64, err error) {
+	for _, env := range t.Data {
+		bytes, err := env.WriteTo(dst)
+		if err != nil {
+			return -1, err
+		}
+		if _, err := dst.Write([]byte{'\n'}); err != nil {
+			return -1, err
+		}
+		n += bytes + 1
+	}
+	return n, nil
+}
+
+func (t *Table) ReadFrom(src io.Reader) (n int64, err error) {
+	decoder := NewDecoder(src)
+	for {
+		env, err := decoder.Decode()
+		if err == io.EOF {
+			return 0, nil
+		} else if err != nil {
+			return -1, err
+		}
+		t.Add(env)
+	}
+	return 0, nil
+}

engine/streams.go

@@ -190,3 +190,19 @@ func (o *Output) AddEnv() (dst *Env, err error) {
 	}()
 	return dst, nil
 }
+
+func (o *Output) AddTable() (dst *Table, err error) {
+	src, err := o.AddPipe()
+	if err != nil {
+		return nil, err
+	}
+	dst = NewTable("", 0)
+	o.tasks.Add(1)
+	go func() {
+		defer o.tasks.Done()
+		if _, err := dst.ReadFrom(src); err != nil {
+			return
+		}
+	}()
+	return dst, nil
+}

engine/table_test.go

@@ -0,0 +1,28 @@
+package engine
+
+import (
+	"testing"
+	"bytes"
+	"encoding/json"
+)
+
+func TestTableWriteTo(t *testing.T) {
+	table := NewTable("", 0)
+	e := &Env{}
+	e.Set("foo", "bar")
+	table.Add(e)
+	var buf bytes.Buffer
+	if _, err := table.WriteTo(&buf); err != nil {
+		t.Fatal(err)
+	}
+	output := make(map[string]string)
+	if err := json.Unmarshal(buf.Bytes(), &output); err != nil {
+		t.Fatal(err)
+	}
+	if len(output) != 1  {
+		t.Fatalf("Incorrect output: %v", output)
+	}
+	if val, exists := output["foo"]; !exists || val != "bar" {
+		t.Fatalf("Inccorect output: %v", output)
+	}
+}