Merge pull request #295 from mvo5/refactor/snap-info-fixes2

Refactor/snap info fixes2

snap/clickdeb/deb.go

@@ -50,7 +50,9 @@ var (
 )
 
 func init() {
-	snap.RegisterBackend([]byte("!<arch>\ndebian"), func(path string) (snap.File, error) {
+	// we need to wrap "Open()" here because stock Open returns
+	// a *ClickDeb and not a snap.File
+	snap.RegisterFormat([]byte("!<arch>\ndebian"), func(path string) (snap.File, error) {
 		return Open(path)
 	})
 }
@@ -541,5 +543,5 @@ func (d *ClickDeb) Info() (*snap.Info, error) {
 		return nil, fmt.Errorf("info failed for %s: %s", d.file.Name(), err)
 	}
 
-	return snap.NewFromPackageYaml(packageYaml)
+	return snap.InfoFromPackageYaml(packageYaml)
 }

snap/file.go

@@ -43,17 +43,17 @@ type File interface {
 	Info() (*Info, error)
 }
 
-// Backend implements a specific snap format
-type Backend struct {
+// backend implements a specific snap format
+type snapFormat struct {
 	magic []byte
 	open  func(fn string) (File, error)
 }
 
-var backends []Backend
+var formatHandlers []snapFormat
 
-// RegisterBackend registers a snap file backend to the system
-func RegisterBackend(magic []byte, open func(fn string) (File, error)) {
-	backends = append(backends, Backend{magic, open})
+// RegisterFormat registers a snap file format to the system
+func RegisterFormat(magic []byte, open func(fn string) (File, error)) {
+	formatHandlers = append(formatHandlers, snapFormat{magic, open})
 }
 
 // Open opens a given snap file with the right backend
@@ -69,9 +69,9 @@ func Open(path string) (File, error) {
 		return nil, fmt.Errorf("cannot read snap: %v", err)
 	}
 
-	for _, be := range backends {
-		if bytes.HasPrefix(header, be.magic) {
-			return be.open(path)
+	for _, h := range formatHandlers {
+		if bytes.HasPrefix(header, h.magic) {
+			return h.open(path)
 		}
 	}
 

snap/info_package_yaml.go

@@ -24,8 +24,8 @@ import (
 	"gopkg.in/yaml.v2"
 )
 
-// NewFromPackageYaml creates a new info based on the given packageYaml
-func NewFromPackageYaml(yamlData []byte) (*Info, error) {
+// InfoFromPackageYaml creates a new info based on the given packageYaml
+func InfoFromPackageYaml(yamlData []byte) (*Info, error) {
 	var s Info
 	err := yaml.Unmarshal(yamlData, &s)
 	if err != nil {

snap/info_package_yaml_test.go

@@ -39,14 +39,14 @@ type: app
 `)
 
 func (s *InfoPackageYamlTestSuite) TestSimple(c *C) {
-	info, err := NewFromPackageYaml(mockYaml)
+	info, err := InfoFromPackageYaml(mockYaml)
 	c.Assert(err, IsNil)
 	c.Assert(info.Name, Equals, "foo")
 	c.Assert(info.Version, Equals, "1.0")
 	c.Assert(info.Type, Equals, TypeApp)
 }
 
 func (s *InfoPackageYamlTestSuite) TestFail(c *C) {
-	_, err := NewFromPackageYaml([]byte("random-crap"))
+	_, err := InfoFromPackageYaml([]byte("random-crap"))
 	c.Assert(err, ErrorMatches, "(?m)info failed to parse:.*")
 }

snap/squashfs/squashfs.go

@@ -35,7 +35,7 @@ import (
 )
 
 func init() {
-	snap.RegisterBackend([]byte{'h', 's', 'q', 's'}, func(path string) (snap.File, error) {
+	snap.RegisterFormat([]byte{'h', 's', 'q', 's'}, func(path string) (snap.File, error) {
 		return New(path), nil
 	})
 }
@@ -142,7 +142,7 @@ func (s *Snap) Info() (*snap.Info, error) {
 		return nil, fmt.Errorf("info failed for %s: %s", s.path, err)
 	}
 
-	return snap.NewFromPackageYaml(packageYaml)
+	return snap.InfoFromPackageYaml(packageYaml)
 }
 
 // HashDigest computes a hash digest of the snap file using the given hash.

snappy/click.go

@@ -1,7 +1,7 @@
 // -*- Mode: Go; indent-tabs-mode: t -*-
 
 /*
- * Copyyright (C) 2014-2015 Canonical Ltd
+ * Copyright (C) 2014-2016 Canonical Ltd
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as