File model and api is almost complete

- Added "Kind" field to File model
- Added file query
- Added editFile mutation
- Added removeFile mutation

model/file/file.go

@@ -19,6 +19,7 @@ var fileCollection *mgo.Collection
 type File struct {
 	ID       string    `bson:"_id" json:"id"`
 	Time     time.Time `bson:"time" json:"time"`
+	Kind     string    `bson:"kind" json:"kind"`
 	Public   bool      `bson:"public" json:"public"`
 	Name     string    `bson:"name" json:"name"`
 	MimeType string    `bson:"mimeType" json:"mimeType"`
@@ -27,6 +28,53 @@ type File struct {
 	URL      string    `bson:"url,omitempty" json:"url,omitempty"`
 }
 
+// Edit edits the file, changing up to both the two mutable properties
+func (file *File) Edit(name *string, public *bool) error {
+	changes := bson.M{}
+	changedFile := *file
+
+	if name != nil && *name != file.Name {
+		changes["name"] = *name
+		changedFile.Name = *name
+	}
+	if public != nil && *public != file.Public {
+		changes["public"] = *public
+		changedFile.Public = *public
+	}
+
+	if len(changes) == 0 {
+		return nil
+	}
+
+	err := fileCollection.UpdateId(file.ID, bson.M{"$set": changes})
+	if err != nil {
+		return err
+	}
+
+	*file = changedFile
+
+	return nil
+}
+
+// Delete removes the file information from the database, and deletes the file.
+func (file *File) Delete() error {
+	err := fileCollection.RemoveId(file.ID)
+	if err != nil {
+		return err
+	}
+
+	if file.Kind == "upload" {
+		err = store.RemoveFile("files", file.ID)
+		if err != nil {
+			return err
+		}
+	}
+
+	file.URL = ""
+
+	return nil
+}
+
 // Upload adds a file to the space.
 func Upload(ctx context.Context, name, mimeType, author string, size int64, input io.Reader) (File, error) {
 	if name == "" {
@@ -47,6 +95,7 @@ func Upload(ctx context.Context, name, mimeType, author string, size int64, inpu
 
 	file := File{
 		ID:       id,
+		Kind:     "upload",
 		Time:     time.Now(),
 		Public:   false,
 		Author:   author,