/// <summary>
/// Returns all values from array according index. If index are MaxValue, return all values
/// </summary>
public static IEnumerable <BsonValue> Array(IEnumerable <BsonValue> values, int index, BsonExpression expr, BsonDocument root)
{
foreach (var value in values)
{
if (value.IsArray)
{
var arr = value.AsArray;
// [<expr>] - index are an expression
if (expr.Source != null)
{
foreach (var item in arr)
{
// execute for each child value and except a first bool value (returns if true)
var c = expr.Execute(root, item, true).First();
if (c.IsBoolean && c.AsBoolean == true)
{
// fill destroy action to remove value from parent array
item.Destroy = () => arr.Remove(item);
yield return(item);
}
}
}
// [*] - index are all values
else if (index == int.MaxValue)
{
foreach (var item in arr)
{
// fill destroy action to remove value from parent array
item.Destroy = () => arr.Remove(item);
yield return(item);
}
}
// [n] - fixed index
else
{
var idx = index < 0 ? arr.Count + index : index;
if (arr.Count > idx)
{
var item = arr[idx];
// fill destroy action to remove value from parent array
item.Destroy = () => arr.Remove(item);
yield return(item);
}
}
}
}
}
/// <summary>
/// Create a new index (or do nothing if already exists) to a collection/field
/// </summary>
public bool EnsureIndex(string collection, string field, string expression, bool unique = false)
{
if (collection.IsNullOrWhiteSpace())
{
throw new ArgumentNullException(nameof(collection));
}
if (!CollectionIndex.IndexPattern.IsMatch(field))
{
throw new ArgumentException("Invalid field format pattern: " + CollectionIndex.IndexPattern.ToString(), "field");
}
if (field == "_id")
{
return(false); // always exists
}
if (expression != null && expression.Length > 200)
{
throw new ArgumentException("expression is limited in 200 characters", "expression");
}
return(Transaction <bool>(collection, true, (col) =>
{
// check if index already exists
var current = col.GetIndex(field);
// if already exists, just exit
if (current != null)
{
// do not test any difference between current index and new defition
return false;
}
// create index head
var index = _indexer.CreateIndex(col);
index.Field = field;
index.Expression = expression ?? "$." + field;
index.Unique = unique;
_log.Write(Logger.Command, "create index on '{0}' :: {1} unique: {2}", collection, index.Expression, unique);
// read all objects (read from PK index)
foreach (var pkNode in new QueryAll("_id", Query.Ascending).Run(col, _indexer))
{
// read binary and deserialize document
var buffer = _data.Read(pkNode.DataBlock);
var doc = _bsonReader.Deserialize(buffer).AsDocument;
var expr = new BsonExpression(index.Expression);
// get values from expression in document
var keys = expr.Execute(doc, true);
// adding index node for each value
foreach (var key in keys)
{
// insert new index node
var node = _indexer.AddNode(index, key, pkNode);
// link index node to datablock
node.DataBlock = pkNode.DataBlock;
}
// check memory usage
_trans.CheckPoint();
}
return true;
}));
}
/// <summary>
/// Get an IEnumerable of values from a json-like path inside document. Use BsonExpression to parse this path
/// </summary>
public IEnumerable <BsonValue> Get(string path, bool includeNullIfEmpty = false)
{
var expr = new BsonExpression(new StringScanner(path), true, true);
return(expr.Execute(this, includeNullIfEmpty));
}