/// <summary>
/// Implement a JSON-Path like navigation on BsonDocument. Support a simple range of paths
/// </summary>
private static Expression ParsePath(StringScanner s, Expression expr, ParameterExpression root)
{
if (s.Match(@"\.[\$\-\w]+"))
{
var method = typeof(BsonExpression).GetMethod("Member");
var name = Expression.Constant(s.Scan(@"\.([\$\-\w]+)", 1));
return(Expression.Call(method, expr, name));
}
else if (s.Match(@"\["))
{
var method = typeof(BsonExpression).GetMethod("Array");
var i = s.Scan(@"\[\s*(-?[\d+\*])\s*\]", 1);
var index = i != "*" && i != "" ? Convert.ToInt32(i) : int.MaxValue;
var inner = new BsonExpression(null);
if (i == "") // if array operation are not index based, read expression
{
s.Scan(@"\[\s*");
// read expression with full support to all operators/formulas
inner = ReadExpression(s, true, false, false);
if (inner == null)
{
throw LiteException.SyntaxError(s, "Invalid expression formula");
}
s.Scan(@"\s*\]");
}
return(Expression.Call(method, expr, Expression.Constant(index), Expression.Constant(inner), root));
}
else
{
return(null);
}
}
/// <summary>
/// Throw syntax exception if not terminate string
/// </summary>
public void ThrowIfNotFinish()
{
Scan(@"\s*");
if (!HasTerminated)
{
throw LiteException.SyntaxError(this);
}
}
/// <summary>
/// Start parse string into linq expression. Read path, function or base type bson values (int, double, bool, string)
/// </summary>
internal static Expression ParseSingleExpression(StringScanner s, ParameterExpression root, ParameterExpression current, bool isRoot)
{
if (s.Match(@"[\$@]") || isRoot) // read root path
{
var r = s.Scan(@"[\$@]"); // read root/current
var method = typeof(BsonExpression).GetMethod("Root");
var name = Expression.Constant(s.Scan(@"\.?([\$\-\w]+)", 1));
var expr = Expression.Call(method, r == "@" ? current : root, name) as Expression;
// parse the rest of path
while (!s.HasTerminated)
{
var result = ParsePath(s, expr, root);
if (result == null)
{
break;
}
expr = result;
}
return(expr);
}
else if (s.Match(@"-?\d*\.\d+")) // read double
{
var number = Convert.ToDouble(s.Scan(@"-?\d*\.\d+"), CultureInfo.InvariantCulture.NumberFormat);
var value = Expression.Constant(new BsonValue(number));
return(Expression.NewArrayInit(typeof(BsonValue), value));
}
else if (s.Match(@"-?\d+")) // read int
{
var number = Convert.ToInt32(s.Scan(@"-?\d+"), CultureInfo.InvariantCulture.NumberFormat);
var value = Expression.Constant(new BsonValue(number));
return(Expression.NewArrayInit(typeof(BsonValue), value));
}
else if (s.Match(@"(true|false)")) // read bool
{
var boolean = Convert.ToBoolean(s.Scan(@"(true|false)"));
var value = Expression.Constant(new BsonValue(boolean));
return(Expression.NewArrayInit(typeof(BsonValue), value));
}
else if (s.Match(@"null")) // read null
{
var value = Expression.Constant(BsonValue.Null);
return(Expression.NewArrayInit(typeof(BsonValue), value));
}
else if (s.Match(@"'")) // read string
{
var str = s.Scan(@"'([\s\S]*?)'", 1);
var value = Expression.Constant(new BsonValue(str));
return(Expression.NewArrayInit(typeof(BsonValue), value));
}
else if (s.Scan(@"\{\s*").Length > 0) // read document {
{
// read key value
var method = typeof(ExpressionOperators).GetMethod("DOCUMENT");
var keys = new List <Expression>();
var values = new List <Expression>();
while (!s.HasTerminated)
{
// read key + value
var key = s.Scan(@"(.+?)\s*:\s*", 1).ThrowIfEmpty("Invalid token", s);
var value = ParseExpression(s, root, current, false);
// add key and value to parameter list (as an expression)
keys.Add(Expression.Constant(new BsonValue(key)));
values.Add(value);
if (s.Scan(@"\s*,\s*").Length > 0)
{
continue;
}
else if (s.Scan(@"\s*\}\s*").Length > 0)
{
break;
}
throw LiteException.SyntaxError(s);
}
var arrKeys = Expression.NewArrayInit(typeof(BsonValue), keys.ToArray());
var arrValues = Expression.NewArrayInit(typeof(IEnumerable <BsonValue>), values.ToArray());
return(Expression.Call(method, new Expression[] { arrKeys, arrValues }));
}
else if (s.Scan(@"\[\s*").Length > 0) // read array [
{
var method = typeof(ExpressionOperators).GetMethod("ARRAY");
var values = new List <Expression>();
while (!s.HasTerminated)
{
// read value expression
var value = ParseExpression(s, root, current, false);
values.Add(value);
if (s.Scan(@"\s*,\s*").Length > 0)
{
continue;
}
else if (s.Scan(@"\s*\]\s*").Length > 0)
{
break;
}
throw LiteException.SyntaxError(s);
}
var arrValues = Expression.NewArrayInit(typeof(IEnumerable <BsonValue>), values.ToArray());
return(Expression.Call(method, new Expression[] { arrValues }));
}
else if (s.Scan(@"\(\s*").Length > 0) // read inner (
{
// read a inner expression inside ( and )
var inner = ParseExpression(s, root, current, false);
if (s.Scan(@"\s*\)").Length == 0)
{
throw LiteException.SyntaxError(s);
}
return(inner);
}
else if (s.Match(@"\w+\s*\(")) // read function
{
// get static method from this class
var name = s.Scan(@"(\w+)\s*\(", 1).ToUpper();
var parameters = new List <Expression>();
if (s.Scan(@"\s*\)\s*").Length == 0)
{
while (!s.HasTerminated)
{
var parameter = ParseExpression(s, root, current, false);
parameters.Add(parameter);
if (s.Scan(@"\s*,\s*").Length > 0)
{
continue;
}
else if (s.Scan(@"\s*\)\s*").Length > 0)
{
break;
}
throw LiteException.SyntaxError(s);
}
}
var method = _methods.FirstOrDefault(x => x.Name == name && x.GetParameters().Count() == parameters.Count);
if (method == null)
{
throw LiteException.SyntaxError(s, "Method " + name + " not exist or invalid parameter count");
}
return(Expression.Call(method, parameters.ToArray()));
}
throw LiteException.SyntaxError(s);
}
