webdav

type Condition struct {
	Not   bool
	Token string
	ETag  string
}

type Dir string

type File interface {
	http.File
	io.Writer
}

type FileSystem interface {
	Mkdir(name string, perm os.FileMode) error
	OpenFile(name string, flag int, perm os.FileMode) (File, error)
	RemoveAll(name string) error
	Rename(oldName, newName string) error
	Stat(name string) (os.FileInfo, error)
}

type Handler struct {
	// FileSystem is the virtual file system.
	FileSystem FileSystem
	// LockSystem is the lock management system.
	LockSystem LockSystem
	// PropSystem is an optional property management system. If non-nil, TODO.
	PropSystem PropSystem
	// Logger is an optional error logger. If non-nil, it will be called
	// for all HTTP requests.
	Logger func(*http.Request, error)
}

type LockDetails struct {
	// Root is the root resource name being locked. For a zero-depth lock, the
	// root is the only resource being locked.
	Root string
	// Duration is the lock timeout. A negative duration means infinite.
	Duration time.Duration
	// OwnerXML is the verbatim <owner> XML given in a LOCK HTTP request.
	//
	// TODO: does the "verbatim" nature play well with XML namespaces?
	// Does the OwnerXML field need to have more structure? See
	// https://codereview.appspot.com/175140043/#msg2
	OwnerXML string
	// ZeroDepth is whether the lock has zero depth. If it does not have zero
	// depth, it has infinite depth.
	ZeroDepth bool
}

type LockSystem interface {
	// Confirm confirms that the caller can claim all of the locks specified by
	// the given conditions, and that holding the union of all of those locks
	// gives exclusive access to the named resource.
	//
	// Exactly one of r and err will be non-nil. If r is non-nil, all of the
	// requested locks are held until r.Release is called.
	//
	// If Confirm returns ErrConfirmationFailed then the Handler will continue
	// to try any other set of locks presented (a WebDAV HTTP request can
	// present more than one set of locks). If it returns any other non-nil
	// error, the Handler will write a "500 Internal Server Error" HTTP status.
	Confirm(now time.Time, name string, conditions ...Condition) (r Releaser, err error)

	// Create creates a lock with the given depth, duration, owner and root
	// (name). The depth will either be negative (meaning infinite) or zero.
	//
	// If Create returns ErrLocked then the Handler will write a "423 Locked"
	// HTTP status. If it returns any other non-nil error, the Handler will
	// write a "500 Internal Server Error" HTTP status.
	//
	// See http://www.webdav.org/specs/rfc4918.html#rfc.section.9.10.6 for
	// when to use each error.
	//
	// The token returned identifies the created lock. It should be an absolute
	// URI as defined by RFC 3986, Section 4.3. In particular, it should not
	// contain whitespace.
	Create(now time.Time, details LockDetails) (token string, err error)

	// Refresh refreshes the lock with the given token.
	//
	// If Refresh returns ErrLocked then the Handler will write a "423 Locked"
	// HTTP Status. If Refresh returns ErrNoSuchLock then the Handler will write
	// a "412 Precondition Failed" HTTP Status. If it returns any other non-nil
	// error, the Handler will write a "500 Internal Server Error" HTTP status.
	//
	// See http://www.webdav.org/specs/rfc4918.html#rfc.section.9.10.6 for
	// when to use each error.
	Refresh(now time.Time, token string, duration time.Duration) (LockDetails, error)

	// Unlock unlocks the lock with the given token.
	//
	// If Unlock returns ErrForbidden then the Handler will write a "403
	// Forbidden" HTTP Status. If Unlock returns ErrLocked then the Handler
	// will write a "423 Locked" HTTP status. If Unlock returns ErrNoSuchLock
	// then the Handler will write a "409 Conflict" HTTP Status. If it returns
	// any other non-nil error, the Handler will write a "500 Internal Server
	// Error" HTTP status.
	//
	// See http://www.webdav.org/specs/rfc4918.html#rfc.section.9.11.1 for
	// when to use each error.
	Unlock(now time.Time, token string) error
}

type PropSystem interface{}

type Property struct {
	// XMLName is the fully qualified name that identifies this property.
	XMLName xml.Name

	// Lang is an optional xml:lang attribute.
	Lang string `xml:"xml:lang,attr,omitempty"`

	// InnerXML contains the XML representation of the property value.
	// See http://www.webdav.org/specs/rfc4918.html#property_values
	//
	// Property values of complex type or mixed-content must have fully
	// expanded XML namespaces or be self-contained with according
	// XML namespace declarations. They must not rely on any XML
	// namespace declarations within the scope of the XML document,
	// even including the DAV: namespace.
	InnerXML []byte `xml:",innerxml"`
}

type Releaser interface {
	Release()
}