1 files changed, 235 insertions, 0 deletions
diff --git a/graph/tags.go b/graph/tags.go
new file mode 100644
index 0000000000..524e1a1f9d
--- /dev/null
+++ b/graph/tags.go
@@ -0,0 +1,235 @@
+package graph
+
+import (
+	"encoding/json"
+	"fmt"
+	"github.com/dotcloud/docker/image"
+	"github.com/dotcloud/docker/utils"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+)
+
+const DEFAULTTAG = "latest"
+
+type TagStore struct {
+	path         string
+	graph        *Graph
+	Repositories map[string]Repository
+}
+
+type Repository map[string]string
+
+func NewTagStore(path string, graph *Graph) (*TagStore, error) {
+	abspath, err := filepath.Abs(path)
+	if err != nil {
+		return nil, err
+	}
+	store := &TagStore{
+		path:         abspath,
+		graph:        graph,
+		Repositories: make(map[string]Repository),
+	}
+	// Load the json file if it exists, otherwise create it.
+	if err := store.Reload(); os.IsNotExist(err) {
+		if err := store.Save(); err != nil {
+			return nil, err
+		}
+	} else if err != nil {
+		return nil, err
+	}
+	return store, nil
+}
+
+func (store *TagStore) Save() error {
+	// Store the json ball
+	jsonData, err := json.Marshal(store)
+	if err != nil {
+		return err
+	}
+	if err := ioutil.WriteFile(store.path, jsonData, 0600); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (store *TagStore) Reload() error {
+	jsonData, err := ioutil.ReadFile(store.path)
+	if err != nil {
+		return err
+	}
+	if err := json.Unmarshal(jsonData, store); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (store *TagStore) LookupImage(name string) (*image.Image, error) {
+	// FIXME: standardize on returning nil when the image doesn't exist, and err for everything else
+	// (so we can pass all errors here)
+	repos, tag := utils.ParseRepositoryTag(name)
+	if tag == "" {
+		tag = DEFAULTTAG
+	}
+	img, err := store.GetImage(repos, tag)
+	if err != nil {
+		return nil, err
+	} else if img == nil {
+		if img, err = store.graph.Get(name); err != nil {
+			return nil, err
+		}
+	}
+	return img, nil
+}
+
+// Return a reverse-lookup table of all the names which refer to each image
+// Eg. {"43b5f19b10584": {"base:latest", "base:v1"}}
+func (store *TagStore) ByID() map[string][]string {
+	byID := make(map[string][]string)
+	for repoName, repository := range store.Repositories {
+		for tag, id := range repository {
+			name := repoName + ":" + tag
+			if _, exists := byID[id]; !exists {
+				byID[id] = []string{name}
+			} else {
+				byID[id] = append(byID[id], name)
+				sort.Strings(byID[id])
+			}
+		}
+	}
+	return byID
+}
+
+func (store *TagStore) ImageName(id string) string {
+	if names, exists := store.ByID()[id]; exists && len(names) > 0 {
+		return names[0]
+	}
+	return utils.TruncateID(id)
+}
+
+func (store *TagStore) DeleteAll(id string) error {
+	names, exists := store.ByID()[id]
+	if !exists || len(names) == 0 {
+		return nil
+	}
+	for _, name := range names {
+		if strings.Contains(name, ":") {
+			nameParts := strings.Split(name, ":")
+			if _, err := store.Delete(nameParts[0], nameParts[1]); err != nil {
+				return err
+			}
+		} else {
+			if _, err := store.Delete(name, ""); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func (store *TagStore) Delete(repoName, tag string) (bool, error) {
+	deleted := false
+	if err := store.Reload(); err != nil {
+		return false, err
+	}
+	if r, exists := store.Repositories[repoName]; exists {
+		if tag != "" {
+			if _, exists2 := r[tag]; exists2 {
+				delete(r, tag)
+				if len(r) == 0 {
+					delete(store.Repositories, repoName)
+				}
+				deleted = true
+			} else {
+				return false, fmt.Errorf("No such tag: %s:%s", repoName, tag)
+			}
+		} else {
+			delete(store.Repositories, repoName)
+			deleted = true
+		}
+	} else {
+		fmt.Errorf("No such repository: %s", repoName)
+	}
+	return deleted, store.Save()
+}
+
+func (store *TagStore) Set(repoName, tag, imageName string, force bool) error {
+	img, err := store.LookupImage(imageName)
+	if err != nil {
+		return err
+	}
+	if tag == "" {
+		tag = DEFAULTTAG
+	}
+	if err := validateRepoName(repoName); err != nil {
+		return err
+	}
+	if err := validateTagName(tag); err != nil {
+		return err
+	}
+	if err := store.Reload(); err != nil {
+		return err
+	}
+	var repo Repository
+	if r, exists := store.Repositories[repoName]; exists {
+		repo = r
+	} else {
+		repo = make(map[string]string)
+		if old, exists := store.Repositories[repoName]; exists && !force {
+			return fmt.Errorf("Conflict: Tag %s:%s is already set to %s", repoName, tag, old)
+		}
+		store.Repositories[repoName] = repo
+	}
+	repo[tag] = img.ID
+	return store.Save()
+}
+
+func (store *TagStore) Get(repoName string) (Repository, error) {
+	if err := store.Reload(); err != nil {
+		return nil, err
+	}
+	if r, exists := store.Repositories[repoName]; exists {
+		return r, nil
+	}
+	return nil, nil
+}
+
+func (store *TagStore) GetImage(repoName, tagOrID string) (*image.Image, error) {
+	repo, err := store.Get(repoName)
+	if err != nil {
+		return nil, err
+	} else if repo == nil {
+		return nil, nil
+	}
+	if revision, exists := repo[tagOrID]; exists {
+		return store.graph.Get(revision)
+	}
+	// If no matching tag is found, search through images for a matching image id
+	for _, revision := range repo {
+		if strings.HasPrefix(revision, tagOrID) {
+			return store.graph.Get(revision)
+		}
+	}
+	return nil, nil
+}
+
+// Validate the name of a repository
+func validateRepoName(name string) error {
+	if name == "" {
+		return fmt.Errorf("Repository name can't be empty")
+	}
+	return nil
+}
+
+// Validate the name of a tag
+func validateTagName(name string) error {
+	if name == "" {
+		return fmt.Errorf("Tag name can't be empty")
+	}
+	if strings.Contains(name, "/") || strings.Contains(name, ":") {
+		return fmt.Errorf("Illegal tag name: %s", name)
+	}
+	return nil
+}