public static T ReadAs <T>(this RecordBase record, string path)
{
RecordBase rec = RecordFromPath(record, path);
if (rec is ScalerRecord scaler)
{
return(scaler.ReadAs <T>());
}
else
{
throw new Exception("value in specific path is not a scaler");
}
}
public static bool TryReadAs <T>(this RecordBase record, string path, out T value)
{
if (!TryGetRecordFromPath(record, path, out RecordBase rec))
{
value = default(T);
return(false);
}
if (rec is ScalerRecord scaler)
{
return(scaler.TryReadAs <T>(out value));
}
else
{
value = default(T);
return(false);
}
}
public static RecordBase RecordFromPath(this RecordBase record, string path)
{
if (path == null)
{
throw new ArgumentNullException(nameof(path));
}
if (record == null)
{
throw new ArgumentNullException(nameof(record));
}
if (path.Length <= 0)
{
throw new ArgumentException("path cannot be empty");
}
RecordBase current = record;
char ch;
int index = 0;
int len = path.Length;
int state = 1;
StringBuilder builder = new StringBuilder(path.Length);
string key;
int listindex;
while (true)
{
if (index >= path.Length)
{
if (state == 3)
{
key = builder.ToString();
if (current is SetRecord set)
{
current = set[key];
}
else
{
throw new Exception($"record is not a set while trying to read property {key}");
}
}
else if (state == 2 || state == 4 || state == 6)
{
throw new Exception("unexcepted end of path");
}
break;
}
ch = path[index];
if (state == 1)
{
if (ch == '[')
{
state = 2;
}
else if (ch.IsValidNameChar())
{
builder.Append(ch); state = 3;
}
else
{
throw new Exception($"unexcepted char {ch}");
}
}
else if (state == 2)
{
if (ch.IsNumber())
{
builder.Append(ch); state = 4;
}
else
{
throw new Exception($"unexcepted char {ch}");
}
}
else if (state == 3)
{
if (ch == '[')
{
key = builder.ToString();
if (current is SetRecord set)
{
current = set[key];
}
else
{
throw new Exception($"record is not a set while trying to read property {key}");
}
builder.Clear();
state = 2;
}
else if (ch.IsValidNameChar())
{
builder.Append(ch);
}
else if (ch == '.')
{
key = builder.ToString();
if (current is SetRecord set)
{
current = set[key];
}
else
{
throw new Exception($"record is not a set while trying to read property {key}");
}
builder.Clear();
state = 6;
}
else
{
throw new Exception($"unexcepted char {ch}");
}
}
else if (state == 4)
{
if (ch.IsNumber())
{
builder.Append(ch);
}
else if (ch == ']')
{
listindex = int.Parse(builder.ToString());
if (current is ListRecord list)
{
current = list[listindex];
}
else
{
throw new Exception($"record is not a list while trying to read element at {listindex}");
}
builder.Clear();
state = 5;
}
else
{
throw new Exception($"unexcepted char {ch}");
}
}
else if (state == 5)
{
if (ch == '[')
{
state = 2;
}
else if (ch == '.')
{
state = 6;
}
else
{
throw new Exception($"unexcepted char {ch}");
}
}
else if (state == 6)
{
if (ch.IsValidNameChar())
{
builder.Append(ch); state = 3;
}
else
{
throw new Exception($"unexcepted char {ch}");
}
}
else
{
throw new Exception($"unknow state of {state}");
}
index++;
}
return(current);
}
public static bool TryGetRecordFromPath(this RecordBase record, string path, out RecordBase result)
{
if (path == null)
{
result = null;
return(false);
}
if (record == null)
{
result = null;
return(false);
}
if (path.Length <= 0)
{
result = null;
return(false);
}
RecordBase current = record;
char ch;
int index = 0;
int len = path.Length;
int state = 1;
StringBuilder builder = new StringBuilder(path.Length);
string key;
int listindex;
while (true)
{
if (index >= path.Length)
{
if (state == 3)
{
key = builder.ToString();
if (current is SetRecord set)
{
if (!set.TryGetValue(key, out current))
{
result = null;
return(false);
}
}
else
{
result = null;
return(false);
}
}
else if (state == 2 || state == 4 || state == 6)
{
result = null;
return(false);
}
break;
}
ch = path[index];
if (state == 1)
{
if (ch == '[')
{
state = 2;
}
else if (ch.IsValidNameChar())
{
builder.Append(ch); state = 3;
}
else
{
result = null;
return(false);
}
}
else if (state == 2)
{
if (ch.IsNumber())
{
builder.Append(ch); state = 4;
}
else
{
result = null;
return(false);
}
}
else if (state == 3)
{
if (ch == '[')
{
key = builder.ToString();
if (current is SetRecord set)
{
if (!set.TryGetValue(key, out current))
{
result = null;
return(false);
}
}
else
{
result = null;
return(false);
}
builder.Clear();
state = 2;
}
else if (ch.IsValidNameChar())
{
builder.Append(ch);
}
else if (ch == '.')
{
key = builder.ToString();
if (current is SetRecord set)
{
if (!set.TryGetValue(key, out current))
{
result = null;
return(false);
}
}
else
{
result = null;
return(false);
}
builder.Clear();
state = 6;
}
else
{
result = null;
return(false);
}
}
else if (state == 4)
{
if (ch.IsNumber())
{
builder.Append(ch);
}
else if (ch == ']')
{
if (!int.TryParse(builder.ToString(), out listindex))
{
result = null;
return(false);
}
if (current is ListRecord list)
{
if (list.Count <= listindex)
{
result = null;
return(false);
}
current = list[listindex];
}
else
{
result = null;
return(false);
}
builder.Clear();
state = 5;
}
else
{
result = null;
return(false);
}
}
else if (state == 5)
{
if (ch == '[')
{
state = 2;
}
else if (ch == '.')
{
state = 6;
}
else
{
result = null;
return(false);
}
}
else if (state == 6)
{
if (ch.IsValidNameChar())
{
builder.Append(ch); state = 3;
}
else
{
result = null;
return(false);
}
}
else
{
result = null;
return(false);
}
index++;
}
result = current;
return(true);
}
