explicitly show plugins as unsupported on !linux

Signed-off-by: Victor Vieux <victorvieux@gmail.com>

plugin/backend.go → plugin/backend_linux.go

@@ -1,3 +1,5 @@
+// +build linux
+
 package plugin
 
 import (

plugin/backend_unsupported.go

@@ -0,0 +1,60 @@
+// +build !linux
+
+package plugin
+
+import (
+	"errors"
+	"io"
+	"net/http"
+
+	"github.com/docker/docker/api/types"
+	"golang.org/x/net/context"
+)
+
+var ErrNotSupported = errors.New("plugins are not supported on this platform")
+
+// Disable deactivates a plugin, which implies that they cannot be used by containers.
+func (pm *Manager) Disable(name string) error {
+	return ErrNotSupported
+}
+
+// Enable activates a plugin, which implies that they are ready to be used by containers.
+func (pm *Manager) Enable(name string) error {
+	return ErrNotSupported
+}
+
+// Inspect examines a plugin config
+func (pm *Manager) Inspect(name string) (tp types.Plugin, err error) {
+	return tp, ErrNotSupported
+}
+
+// Pull pulls a plugin and computes the privileges required to install it.
+func (pm *Manager) Pull(name string, metaHeader http.Header, authConfig *types.AuthConfig) (types.PluginPrivileges, error) {
+	return nil, ErrNotSupported
+}
+
+// List displays the list of plugins and associated metadata.
+func (pm *Manager) List() ([]types.Plugin, error) {
+	return nil, ErrNotSupported
+}
+
+// Push pushes a plugin to the store.
+func (pm *Manager) Push(name string, metaHeader http.Header, authConfig *types.AuthConfig) error {
+	return ErrNotSupported
+}
+
+// Remove deletes plugin's root directory.
+func (pm *Manager) Remove(name string, config *types.PluginRmConfig) error {
+	return ErrNotSupported
+}
+
+// Set sets plugin args
+func (pm *Manager) Set(name string, args []string) error {
+	return ErrNotSupported
+}
+
+// CreateFromContext creates a plugin from the given pluginDir which contains
+// both the rootfs and the config.json and a repoName with optional tag.
+func (pm *Manager) CreateFromContext(ctx context.Context, tarCtx io.Reader, options *types.PluginCreateOptions) error {
+	return ErrNotSupported
+}