/// <summary>
/// Deserialize a json using a StringScanner and returns BsonValue
/// </summary>
public static BsonValue Deserialize(StringScanner s)
{
if (s == null) throw new ArgumentNullException("s");
if (s.HasTerminated) return BsonValue.Null;
using (var sr = new StringReader(s.ToString()))
{
var reader = new JsonReader(sr);
var value = reader.Deserialize();
s.Seek((int)(reader.Position - 1));
return value;
}
}
/// <summary>
/// Parse and compile an expression from a stringscanner. Must define if will read a path only or support for full expression. Can parse only arithmetic (+/-/*/..) or full logic operators (=/!=/>/...)
/// </summary>
private static Func <BsonDocument, BsonValue, IEnumerable <BsonValue> > Compile(StringScanner s, bool pathOnly, bool arithmeticOnly)
{
var isRoot = pathOnly;
var root = Expression.Parameter(typeof(BsonDocument), "root");
var current = Expression.Parameter(typeof(BsonValue), "current");
Expression expr;
if (pathOnly)
{
// if read path, read first expression only
// support missing $ as root
s.Scan(@"\$\.?");
expr = ParseSingleExpression(s, root, current, true);
}
else
{
// read all expression (a + b)
// if include operator, support = > < && || too
expr = ParseExpression(s, root, current, arithmeticOnly);
}
var lambda = Expression.Lambda <Func <BsonDocument, BsonValue, IEnumerable <BsonValue> > >(expr, root, current);
return(lambda.Compile());
}
/// <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+"));
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+"));
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.Match(@"\w+\s*\(")) // read function
{
// get static method from this class
var name = s.Scan(@"(\w+)\s*\(", 1).ToUpper();
var method = typeof(BsonExpression).GetMethod(name);
var parameters = new List <Expression>();
if (method == null)
{
throw LiteException.SyntaxError(s, "Method " + name + " not exist");
}
while (!s.HasTerminated)
{
var parameter = ParseExpression(s, root, current, false);
parameters.Add(parameter);
if (s.Scan(@"\s*,\s*").Length > 0)
{
continue;
}
else if (s.Scan(@"\s*\)\s*").Length > 0)
{
break;
}
throw LiteException.SyntaxError(s);
}
return(Expression.Call(method, parameters.ToArray()));
}
throw LiteException.SyntaxError(s);
}
/// <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+"));
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+"));
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("(.+?):", 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);
}
