private HierarchicalExpression(string[] segments, Reflection.MemberPathSegment[] members)
{
_segments = segments ?? new string[0];
_members = members ?? new Reflection.MemberPathSegment[0];
_anchor = IO.PathAnchor.None;
_path = string.Empty;
if (segments.Length > 0)
{
switch (segments[0])
{
case "":
_anchor = IO.PathAnchor.Root;
break;
case ".":
_anchor = IO.PathAnchor.Current;
break;
case "..":
_anchor = IO.PathAnchor.Parent;
break;
}
if (segments.Length == 1 && segments[0].Length == 0)
{
_path = "/";
}
else
{
_path = string.Join("/", segments);
}
}
}
public StateContext(ReadOnlySpan <char> data)
{
_data = data;
_anchorPosition = -1;
_cursorPosition = -1;
_whitespaces = 0;
this.State = State.None;
this.Character = '\0';
this.Anchor = IO.PathAnchor.None;
}
private static void ParsePath(TextReader reader, out IO.PathAnchor anchor, out string name, out string path)
{
if (reader == null)
{
throw new ArgumentNullException(nameof(reader));
}
var state = CommandPathState.None;
var parts = new List <string>();
var valueRead = 0;
//设置输出参数的默认值
anchor = IO.PathAnchor.None;
name = string.Empty;
path = string.Empty;
while ((valueRead = reader.Read()) > 0)
{
var chr = (char)valueRead;
//首先对位于路径中间的点号进行转换，以方便后续的处理
if (chr == '.' && state == CommandPathState.Part)
{
chr = '/';
}
if (chr == '.')
{
switch (state)
{
case CommandPathState.None:
state = CommandPathState.Dot;
anchor = IO.PathAnchor.Current;
break;
case CommandPathState.Dot:
state = CommandPathState.DoubleDot;
anchor = IO.PathAnchor.Parent;
break;
default:
throw new CommandExpressionException("Invalid anchor of command path.");
}
}
else if (chr == '/')
{
if (state == CommandPathState.Slash)
{
throw new CommandExpressionException("Duplicate '/' slash characters.");
}
if (state == CommandPathState.None)
{
anchor = IO.PathAnchor.Root;
}
else if (state == CommandPathState.Part)
{
parts.Add(name);
name = string.Empty;
}
state = CommandPathState.Slash;
}
else if (Char.IsLetterOrDigit(chr) || chr == '_')
{
if (state == CommandPathState.Dot || state == CommandPathState.DoubleDot)
{
throw new CommandExpressionException("Missing '/' slash character between dot and letter or digit.");
}
name += chr;
state = CommandPathState.Part;
}
else if (Char.IsWhiteSpace(chr))
{
if (state == CommandPathState.None)
{
continue;
}
else
{
break;
}
}
else
{
throw new CommandExpressionException($"Contains '{chr}' illegal character(s) in the command path.");
}
}
//如果路径以斜杠符结尾，即为非法路径格式
if (state == CommandPathState.Slash && ((parts != null && parts.Count > 0) || anchor != IO.PathAnchor.Root))
{
throw new CommandExpressionException("The command path can not at the end of '/' character.");
}
if (parts != null && parts.Count > 0)
{
path = string.Join(".", parts);
}
else if (string.IsNullOrEmpty(name))
{
switch (anchor)
{
case IO.PathAnchor.Root:
name = "/";
break;
case IO.PathAnchor.Current:
name = ".";
break;
case IO.PathAnchor.Parent:
name = "..";
break;
}
anchor = IO.PathAnchor.None;
}
}