imageservice: Use pagination for returning the image members list

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

Author: Samuel Ortiz

openstack/imageservice/v2/members/requests.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 
 	"github.com/rackspace/gophercloud"
+	"github.com/rackspace/gophercloud/pagination"
 )
 
 // Create member for specific image
@@ -48,10 +49,12 @@ func Create(client *gophercloud.ServiceClient, id string, member string) CreateM
 
 // List members returns list of members for specifed image id
 // More details: http://developer.openstack.org/api-ref-image-v2.html#listImageMembers-v2
-func List(client *gophercloud.ServiceClient, id string) ListMembersResult {
-	var res ListMembersResult
-	_, res.Err = client.Get(listMembersURL(client, id), &res.Body, &gophercloud.RequestOpts{OkCodes: []int{200}})
-	return res
+func List(client *gophercloud.ServiceClient, id string) pagination.Pager {
+	createPage := func(r pagination.PageResult) pagination.Page {
+		return MemberPage{pagination.SinglePageBase(r)}
+	}
+
+	return pagination.NewPager(client, listMembersURL(client, id), createPage)
 }
 
 // Get image member details.

openstack/imageservice/v2/members/results.go

@@ -5,6 +5,7 @@ import (
 
 	"github.com/mitchellh/mapstructure"
 	"github.com/rackspace/gophercloud"
+	"github.com/rackspace/gophercloud/pagination"
 )
 
 // ImageMember model
@@ -74,6 +75,31 @@ func (lm ListMembersResult) Extract() ([]ImageMember, error) {
 	return results.ImageMembers, err
 }
 
+// MemberPage is a single page of Members results.
+type MemberPage struct {
+	pagination.SinglePageBase
+}
+
+// ExtractMembers returns a slice of Members contained in a single page of results.
+func ExtractMembers(page pagination.Page) ([]ImageMember, error) {
+	casted := page.(MemberPage).Body
+	var response struct {
+		ImageMembers []ImageMember `mapstructure:"members"`
+	}
+
+	err := mapstructure.Decode(casted, &response)
+	return response.ImageMembers, err
+}
+
+// IsEmpty determines whether or not a page of Members contains any results.
+func (page MemberPage) IsEmpty() (bool, error) {
+	tenants, err := ExtractMembers(page)
+	if err != nil {
+		return false, err
+	}
+	return len(tenants) == 0, nil
+}
+
 // MemberDetailsResult model
 type MemberDetailsResult struct {
 	gophercloud.Result