Move parsing functions to pkg/parsers and the specific kernel handling

functions to pkg/parsers/kernel, and parsing filters to
pkg/parsers/filter. Adjust imports and package references.

Docker-DCO-1.1-Signed-off-by: Erik Hollensbe <github@hollensbe.org> (github: erikh)

parsers/filters/parse.go

@@ -0,0 +1,63 @@
+package filters
+
+import (
+	"encoding/json"
+	"errors"
+	"strings"
+)
+
+type Args map[string][]string
+
+// Parse the argument to the filter flag. Like
+//
+//   `docker ps -f 'created=today' -f 'image.name=ubuntu*'`
+//
+// If prev map is provided, then it is appended to, and returned. By default a new
+// map is created.
+func ParseFlag(arg string, prev Args) (Args, error) {
+	var filters Args = prev
+	if prev == nil {
+		filters = Args{}
+	}
+	if len(arg) == 0 {
+		return filters, nil
+	}
+
+	if !strings.Contains(arg, "=") {
+		return filters, ErrorBadFormat
+	}
+
+	f := strings.SplitN(arg, "=", 2)
+	filters[f[0]] = append(filters[f[0]], f[1])
+
+	return filters, nil
+}
+
+var ErrorBadFormat = errors.New("bad format of filter (expected name=value)")
+
+// packs the Args into an string for easy transport from client to server
+func ToParam(a Args) (string, error) {
+	// this way we don't URL encode {}, just empty space
+	if len(a) == 0 {
+		return "", nil
+	}
+
+	buf, err := json.Marshal(a)
+	if err != nil {
+		return "", err
+	}
+	return string(buf), nil
+}
+
+// unpacks the filter Args
+func FromParam(p string) (Args, error) {
+	args := Args{}
+	if len(p) == 0 {
+		return args, nil
+	}
+	err := json.Unmarshal([]byte(p), &args)
+	if err != nil {
+		return nil, err
+	}
+	return args, nil
+}

parsers/filters/parse_test.go

@@ -0,0 +1,78 @@
+package filters
+
+import (
+	"sort"
+	"testing"
+)
+
+func TestParseArgs(t *testing.T) {
+	// equivalent of `docker ps -f 'created=today' -f 'image.name=ubuntu*' -f 'image.name=*untu'`
+	flagArgs := []string{
+		"created=today",
+		"image.name=ubuntu*",
+		"image.name=*untu",
+	}
+	var (
+		args = Args{}
+		err  error
+	)
+	for i := range flagArgs {
+		args, err = ParseFlag(flagArgs[i], args)
+		if err != nil {
+			t.Errorf("failed to parse %s: %s", flagArgs[i], err)
+		}
+	}
+	if len(args["created"]) != 1 {
+		t.Errorf("failed to set this arg")
+	}
+	if len(args["image.name"]) != 2 {
+		t.Errorf("the args should have collapsed")
+	}
+}
+
+func TestParam(t *testing.T) {
+	a := Args{
+		"created":    []string{"today"},
+		"image.name": []string{"ubuntu*", "*untu"},
+	}
+
+	v, err := ToParam(a)
+	if err != nil {
+		t.Errorf("failed to marshal the filters: %s", err)
+	}
+	v1, err := FromParam(v)
+	if err != nil {
+		t.Errorf("%s", err)
+	}
+	for key, vals := range v1 {
+		if _, ok := a[key]; !ok {
+			t.Errorf("could not find key %s in original set", key)
+		}
+		sort.Strings(vals)
+		sort.Strings(a[key])
+		if len(vals) != len(a[key]) {
+			t.Errorf("value lengths ought to match")
+			continue
+		}
+		for i := range vals {
+			if vals[i] != a[key][i] {
+				t.Errorf("expected %s, but got %s", a[key][i], vals[i])
+			}
+		}
+	}
+}
+
+func TestEmpty(t *testing.T) {
+	a := Args{}
+	v, err := ToParam(a)
+	if err != nil {
+		t.Errorf("failed to marshal the filters: %s", err)
+	}
+	v1, err := FromParam(v)
+	if err != nil {
+		t.Errorf("%s", err)
+	}
+	if len(a) != len(v1) {
+		t.Errorf("these should both be empty sets")
+	}
+}