OP#792 initial commit after fork

internal/bucket/versioning/versioning.go

@@ -0,0 +1,167 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package versioning
+
+import (
+	"encoding/xml"
+	"io"
+	"strings"
+
+	"github.com/minio/pkg/v3/wildcard"
+)
+
+// State - enabled/disabled/suspended states
+// for multifactor and status of versioning.
+type State string
+
+// Various supported states
+const (
+	Enabled State = "Enabled"
+	// Disabled  State = "Disabled" only used by MFA Delete not supported yet.
+	Suspended State = "Suspended"
+)
+
+var (
+	errExcludedPrefixNotSupported = Errorf("excluded prefixes extension supported only when versioning is enabled")
+	errTooManyExcludedPrefixes    = Errorf("too many excluded prefixes")
+)
+
+// ExcludedPrefix - holds individual prefixes excluded from being versioned.
+type ExcludedPrefix struct {
+	Prefix string
+}
+
+// Versioning - Configuration for bucket versioning.
+type Versioning struct {
+	XMLNS   string   `xml:"xmlns,attr,omitempty"`
+	XMLName xml.Name `xml:"VersioningConfiguration"`
+	// MFADelete State    `xml:"MFADelete,omitempty"` // not supported yet.
+	Status State `xml:"Status,omitempty"`
+	// MinIO extension - allows selective, prefix-level versioning exclusion.
+	// Requires versioning to be enabled
+	ExcludedPrefixes []ExcludedPrefix `xml:",omitempty"`
+	ExcludeFolders   bool             `xml:",omitempty"`
+}
+
+// Validate - validates the versioning configuration
+func (v Versioning) Validate() error {
+	// Not supported yet
+	// switch v.MFADelete {
+	// case Enabled, Disabled:
+	// default:
+	// 	return Errorf("unsupported MFADelete state %s", v.MFADelete)
+	// }
+	switch v.Status {
+	case Enabled:
+		const maxExcludedPrefixes = 10
+		if len(v.ExcludedPrefixes) > maxExcludedPrefixes {
+			return errTooManyExcludedPrefixes
+		}
+
+	case Suspended:
+		if len(v.ExcludedPrefixes) > 0 {
+			return errExcludedPrefixNotSupported
+		}
+	default:
+		return Errorf("unsupported Versioning status %s", v.Status)
+	}
+	return nil
+}
+
+// Enabled - returns true if versioning is enabled
+func (v Versioning) Enabled() bool {
+	return v.Status == Enabled
+}
+
+// Versioned returns if 'prefix' has versioning enabled or suspended.
+func (v Versioning) Versioned(prefix string) bool {
+	return v.PrefixEnabled(prefix) || v.PrefixSuspended(prefix)
+}
+
+// PrefixEnabled - returns true if versioning is enabled at the bucket and given
+// prefix, false otherwise.
+func (v Versioning) PrefixEnabled(prefix string) bool {
+	if v.Status != Enabled {
+		return false
+	}
+
+	if prefix == "" {
+		return true
+	}
+	if v.ExcludeFolders && strings.HasSuffix(prefix, "/") {
+		return false
+	}
+
+	for _, sprefix := range v.ExcludedPrefixes {
+		// Note: all excluded prefix patterns end with `/` (See Validate)
+		sprefix.Prefix += "*"
+
+		if matched := wildcard.MatchSimple(sprefix.Prefix, prefix); matched {
+			return false
+		}
+	}
+	return true
+}
+
+// Suspended - returns true if versioning is suspended
+func (v Versioning) Suspended() bool {
+	return v.Status == Suspended
+}
+
+// PrefixSuspended - returns true if versioning is suspended at the bucket level
+// or suspended on the given prefix.
+func (v Versioning) PrefixSuspended(prefix string) bool {
+	if v.Status == Suspended {
+		return true
+	}
+	if v.Status == Enabled {
+		if prefix == "" {
+			return false
+		}
+		if v.ExcludeFolders && strings.HasSuffix(prefix, "/") {
+			return true
+		}
+
+		for _, sprefix := range v.ExcludedPrefixes {
+			// Note: all excluded prefix patterns end with `/` (See Validate)
+			sprefix.Prefix += "*"
+			if matched := wildcard.MatchSimple(sprefix.Prefix, prefix); matched {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+// PrefixesExcluded returns true if v contains one or more excluded object
+// prefixes or if ExcludeFolders is true.
+func (v Versioning) PrefixesExcluded() bool {
+	return len(v.ExcludedPrefixes) > 0 || v.ExcludeFolders
+}
+
+// ParseConfig - parses data in given reader to VersioningConfiguration.
+func ParseConfig(reader io.Reader) (*Versioning, error) {
+	var v Versioning
+	if err := xml.NewDecoder(reader).Decode(&v); err != nil {
+		return nil, err
+	}
+	if err := v.Validate(); err != nil {
+		return nil, err
+	}
+	return &v, nil
+}