/// <summary>
/// Implement upsert command to documents in a collection. Calls update on all documents,
/// then any documents not updated are then attempted to insert.
/// This will have the side effect of throwing if duplicate items are attempted to be inserted.
/// </summary>
public int Upsert(string collection, IEnumerable <BsonDocument> docs, BsonAutoId autoId)
{
if (collection.IsNullOrWhiteSpace())
{
throw new ArgumentNullException(nameof(collection));
}
if (docs == null)
{
throw new ArgumentNullException(nameof(docs));
}
return(this.AutoTransaction(transaction =>
{
var snapshot = transaction.CreateSnapshot(LockMode.Write, collection, true);
var col = snapshot.CollectionPage;
var indexer = new IndexService(snapshot, _header.Pragmas.Collation);
var data = new DataService(snapshot);
var count = 0;
foreach (var doc in docs)
{
transaction.Safepoint();
// first try update document (if exists _id), if not found, do insert
if (doc["_id"] == BsonValue.Null || this.UpdateDocument(snapshot, col, doc, indexer, data) == false)
{
this.InsertDocument(snapshot, doc, autoId, indexer, data);
count++;
}
}
// returns how many document was inserted
return count;
}));
}
/// <summary>
/// Implement update command to a document inside a collection. Return number of documents updated
/// </summary>
public int Update(string collection, IEnumerable <BsonDocument> docs)
{
if (collection.IsNullOrWhiteSpace())
{
throw new ArgumentNullException(nameof(collection));
}
if (docs == null)
{
throw new ArgumentNullException(nameof(docs));
}
return(this.AutoTransaction(transaction =>
{
var snapshot = transaction.CreateSnapshot(LockMode.Write, collection, false);
var col = snapshot.CollectionPage;
var indexer = new IndexService(snapshot);
var data = new DataService(snapshot);
var count = 0;
LOG($"update `{collection}`", "COMMAND");
foreach (var doc in docs)
{
transaction.Safepoint();
if (this.UpdateDocument(snapshot, col, doc, indexer, data))
{
count++;
}
}
return count;
}));
}
public override async IAsyncEnumerable <IndexNode> Run(CollectionPage col, IndexService indexer)
{
var rawId = 0u;
foreach (var doc in _source)
{
rawId++;
// create fake rawId for document source
doc.RawId = new PageAddress(rawId, 0);
// create cache until reach 1000 document - after this, delete cache and remove support
if (_cache != null)
{
_cache[rawId] = doc;
if (_cache.Count > VIRTUAL_INDEX_MAX_CACHE)
{
_cache = null;
}
}
// return an fake indexNode
yield return(new IndexNode(doc));
}
}
/// <summary>
/// Add a new collection. Check if name the not exists. Create only in transaction page - will update header only in commit
/// </summary>
private void Add(string name, ref CollectionPage collectionPage)
{
if (Encoding.UTF8.GetByteCount(name) > _header.GetAvaiableCollectionSpace())
{
throw LiteException.InvalidCollectionName(name, "There is no space in header for more collections");
}
if (!name.IsWord())
{
throw LiteException.InvalidCollectionName(name, "Use only [a-Z$_]");
}
if (name.StartsWith("$"))
{
throw LiteException.InvalidCollectionName(name, "Collection can't starts with `$` (reserved for system collections)");
}
// create new collection page
collectionPage = _snapshot.NewPage <CollectionPage>();
var pageID = collectionPage.PageID;
// insert collection name/pageID in header only in commit operation
_transPages.Commit += (h) => h.InsertCollection(name, pageID);
// create first index (_id pk) (must pass collectionPage because snapshot contains null in CollectionPage prop)
var indexer = new IndexService(_snapshot);
indexer.CreateIndex("_id", "$._id", true);
}
public override IEnumerable <IndexNode> Execute(IndexService indexer, CollectionIndex index)
{
// if contains startsWith string, search using index Find
// otherwise, use index full scan and test results
return(_startsWith.Length > 0 ?
this.ExecuteStartsWith(indexer, index) :
this.ExecuteLike(indexer, index));
}
/// <summary>
/// Implements delete based on IDs enumerable
/// </summary>
public int Delete(string collection, IEnumerable <BsonValue> ids)
{
if (collection.IsNullOrWhiteSpace())
{
throw new ArgumentNullException(nameof(collection));
}
if (ids == null)
{
throw new ArgumentNullException(nameof(ids));
}
return(this.AutoTransaction(transaction =>
{
var snapshot = transaction.CreateSnapshot(LockMode.Write, collection, false);
var collectionPage = snapshot.CollectionPage;
var data = new DataService(snapshot);
var indexer = new IndexService(snapshot, _header.Pragmas.Collation);
if (collectionPage == null)
{
return 0;
}
var count = 0;
var pk = collectionPage.PK;
foreach (var id in ids)
{
var pkNode = indexer.Find(pk, id, false, LiteDB.Query.Ascending);
// if pk not found, continue
if (pkNode == null)
{
continue;
}
// remove object data
data.Delete(pkNode.DataBlock);
if (pkNode.NextNode.IsEmpty)
{
;
}
// delete all nodes (start in pk node)
indexer.DeleteAll(pkNode.Position);
transaction.Safepoint();
count++;
}
return count;
}));
}
public override async IAsyncEnumerable <IndexNode> Execute(IndexService indexer, CollectionIndex index)
{
await foreach (var node in indexer.FindAll(index, this.Order))
{
if (_func(node.Key))
{
yield return(node);
}
}
}
public override IEnumerable <IndexNode> Execute(IndexService indexer, CollectionIndex index)
{
foreach (var value in _values.Distinct())
{
foreach (var node in Index.EQ(this.Name, value).Execute(indexer, index))
{
yield return(node);
}
}
}
private async IAsyncEnumerable <IndexNode> ExecuteLike(IndexService indexer, CollectionIndex index)
{
await foreach (var node in indexer.FindAll(index, this.Order))
{
if (node.Key.IsString && node.Key.AsString.SqlLike(_pattern, indexer.Collation))
{
yield return(node);
}
}
}
public override IEnumerable <IndexNode> Execute(IndexService indexer, CollectionIndex index)
{
foreach (var value in _values.Distinct())
{
var idx = new IndexEquals(this._values, value);
foreach (var node in idx.Execute(indexer, index))
{
yield return(node);
}
}
}
/// <summary>
/// Find witch index will be used and run Execute method
/// </summary>
public virtual IEnumerable <IndexNode> Run(CollectionPage col, IndexService indexer)
{
// get index for this query
var index = col.GetCollectionIndex(this.Name);
if (index == null)
{
throw LiteException.IndexNotFound(this.Name);
}
// execute query to get all IndexNodes
return(this.Execute(indexer, index));
}
public override async IAsyncEnumerable <IndexNode> Execute(IndexService indexer, CollectionIndex index)
{
// if contains startsWith string, search using index Find
// otherwise, use index full scan and test results
var nodes = _startsWith.Length > 0 ?
this.ExecuteStartsWith(indexer, index) :
this.ExecuteLike(indexer, index);
await foreach (var node in nodes)
{
yield return(node);
}
}
/// <summary>
/// Fill current database with data inside file reader - run inside a transacion
/// </summary>
internal void RebuildContent(IFileReader reader, UpgradeOption upgrade = UpgradeOption.True)
{
// begin transaction and get TransactionID
var transaction = _monitor.GetTransaction(true, false, out _);
try
{
foreach (var collection in reader.GetCollections())
{
if (upgrade != UpgradeOption.DataOnly)
{
// first create all user indexes (exclude _id index)
foreach (var index in reader.GetIndexes(collection))
{
this.EnsureIndex(collection,
index.Name,
BsonExpression.Create(index.Expression),
index.Unique);
}
}
// get all documents from current collection
var docs = reader.GetDocuments(collection);
// get snapshot, indexer and data services
var snapshot = transaction.CreateSnapshot(LockMode.Write, collection, true);
var indexer = new IndexService(snapshot, _header.Pragmas.Collation);
var data = new DataService(snapshot);
// insert one-by-one
foreach (var doc in docs)
{
transaction.Safepoint();
this.InsertDocument(snapshot, doc, BsonAutoId.ObjectId, indexer, data);
}
}
transaction.Commit();
}
catch (Exception)
{
_walIndex.Clear();
throw;
}
finally
{
_monitor.ReleaseTransaction(transaction);
}
}
/// <summary>
/// Drop an index from a collection
/// </summary>
public bool DropIndex(string collection, string name)
{
if (collection.IsNullOrWhiteSpace())
{
throw new ArgumentNullException(nameof(collection));
}
if (name.IsNullOrWhiteSpace())
{
throw new ArgumentNullException(nameof(name));
}
if (name == "_id")
{
throw LiteException.IndexDropId();
}
return(this.AutoTransaction(transaction =>
{
var snapshot = transaction.CreateSnapshot(LockMode.Write, collection, false);
var col = snapshot.CollectionPage;
var indexer = new IndexService(snapshot);
// no collection, no index
if (col == null)
{
return false;
}
// search for index reference
var index = col.GetCollectionIndex(name);
// no index, no drop
if (index == null)
{
return false;
}
// delete all data pages + indexes pages
indexer.DropIndex(index);
// remove index entry in collection page
snapshot.CollectionPage.DeleteCollectionIndex(name);
return true;
}));
}
/// <summary>
/// Add a new collection. Check if name the not exists. Create only in transaction page - will update header only in commit
/// </summary>
private void Add(string name, ref CollectionPage collectionPage)
{
// checks for collection name/size
CheckName(name, _header);
// create new collection page
collectionPage = _snapshot.NewPage <CollectionPage>();
var pageID = collectionPage.PageID;
// insert collection name/pageID in header only in commit operation
_transPages.Commit += (h) => h.InsertCollection(name, pageID);
// create first index (_id pk) (must pass collectionPage because snapshot contains null in CollectionPage prop)
var indexer = new IndexService(_snapshot);
indexer.CreateIndex("_id", "$._id", true);
}
public override async IAsyncEnumerable <IndexNode> Execute(IndexService indexer, CollectionIndex index)
{
var node = await indexer.Find(index, _value, false, Query.Ascending);
if (node == null)
{
yield break;
}
yield return(node);
if (index.Unique == false)
{
// navigate in both sides to return all nodes found
var first = node;
// first go forward
while (!node.Next[0].IsEmpty && ((node = await indexer.GetNode(node.Next[0])).Key.CompareTo(_value, indexer.Collation) == 0))
{
if (node.Key.IsMinValue || node.Key.IsMaxValue)
{
break;
}
yield return(node);
}
node = first;
// and than, go backward
while (!node.Prev[0].IsEmpty && ((node = await indexer.GetNode(node.Prev[0])).Key.CompareTo(_value, indexer.Collation) == 0))
{
if (node.Key.IsMinValue || node.Key.IsMaxValue)
{
break;
}
yield return(node);
}
}
}
/// <summary>
/// Get corrent IDocumentLookup
/// </summary>
public IDocumentLookup GetLookup(Snapshot snapshot, bool utcDate)
{
var data = new DataService(snapshot);
var indexer = new IndexService(snapshot);
// define document loader
// if index are VirtualIndex - it's also lookup document
if (!(this.Index is IDocumentLookup lookup))
{
if (this.IsIndexKeyOnly)
{
lookup = new IndexLookup(indexer, this.Fields.Single());
}
else
{
lookup = new DatafileLookup(data, utcDate, this.Fields);
}
}
return(lookup);
}
/// <summary>
/// Implement update command to a document inside a collection. Return number of documents updated
/// </summary>
public async Task <int> UpdateAsync(string collection, IEnumerable <BsonDocument> docs)
{
if (collection.IsNullOrWhiteSpace())
{
throw new ArgumentNullException(nameof(collection));
}
if (docs == null)
{
throw new ArgumentNullException(nameof(docs));
}
return(await this.AutoTransaction(async transaction =>
{
var snapshot = await transaction.CreateSnapshot(LockMode.Write, collection, false);
var collectionPage = snapshot.CollectionPage;
var indexer = new IndexService(snapshot, _header.Pragmas.Collation);
var data = new DataService(snapshot);
var count = 0;
if (collectionPage == null)
{
return 0;
}
LOG($"update `{collection}`", "COMMAND");
foreach (var doc in docs)
{
await transaction.Safepoint();
if (await this.UpdateDocument(snapshot, collectionPage, doc, indexer, data))
{
count++;
}
}
return count;
}));
}
/// <summary>
/// Add a new collection. Check if name the not exists. Create only in transaction page - will update header only in commit
/// </summary>
private async Task <CollectionPage> Add(string name)
{
// checks for collection name/size
CheckName(name, _header);
// create new collection page
var collectionPage = await _snapshot.NewPage <CollectionPage>();
_snapshot.CollectionPage = collectionPage;
var pageID = collectionPage.PageID;
// insert collection name/pageID in header only in commit operation
_transPages.Commit += (h) => h.InsertCollection(name, pageID);
// create first index (_id pk) (must pass collectionPage because snapshot contains null in CollectionPage prop)
var indexer = new IndexService(_snapshot, _header.Pragmas.Collation);
await indexer.CreateIndex("_id", "$._id", true);
return(collectionPage);
}
/// <summary>
/// Find witch index will be used and run Execute method
/// </summary>
public virtual async IAsyncEnumerable <IndexNode> Run(CollectionPage col, IndexService indexer)
{
// get index for this query
var index = col.GetCollectionIndex(this.Name);
if (index == null)
{
throw LiteException.IndexNotFound(this.Name);
}
var distinct = new HashSet <PageAddress>();
await foreach (var node in this.Execute(indexer, index))
{
// distinct by dataBlock
if (distinct.Contains(node.DataBlock) == false)
{
distinct.Add(node.DataBlock);
yield return(node);
}
}
}
/// <summary>
/// INCLUDE: Do include in result document according path expression - Works only with DocumentLookup
/// </summary>
protected async IAsyncEnumerable <BsonDocument> Include(IAsyncEnumerable <BsonDocument> source, BsonExpression path)
{
// cached services
string last = null;
Snapshot snapshot = null;
IndexService indexer = null;
DataService data = null;
CollectionIndex index = null;
IDocumentLookup lookup = null;
await foreach (var doc in source)
{
foreach (var value in path.Execute(doc, _pragmas.Collation)
.Where(x => x.IsDocument || x.IsArray)
.ToList())
{
// if value is document, convert this ref document into full document (do another query)
if (value.IsDocument)
{
await DoInclude(value.AsDocument);
}
else
{
// if value is array, do same per item
foreach (var item in value.AsArray
.Where(x => x.IsDocument)
.Select(x => x.AsDocument))
{
await DoInclude(item);
}
}
}
yield return(doc);
}
async Task DoInclude(BsonDocument value)
{
// works only if is a document
var refId = value["$id"];
var refCol = value["$ref"];
// if has no reference, just go out
if (refId.IsNull || !refCol.IsString)
{
return;
}
// do some cache re-using when is same $ref (almost always is the same $ref collection)
if (last != refCol.AsString)
{
last = refCol.AsString;
// initialize services
snapshot = await _transaction.CreateSnapshot(LockMode.Read, last, false);
indexer = new IndexService(snapshot, _pragmas.Collation);
data = new DataService(snapshot);
lookup = new DatafileLookup(data, _pragmas.UtcDate, null);
index = snapshot.CollectionPage?.PK;
}
// fill only if index and ref node exists
if (index != null)
{
var node = await indexer.Find(index, refId, false, Query.Ascending);
if (node != null)
{
// load document based on dataBlock position
var refDoc = await lookup.Load(node);
//do not remove $id
value.Remove("$ref");
// copy values from refDocument into current documet (except _id - will keep $id)
foreach (var element in refDoc.Where(x => x.Key != "_id"))
{
value[element.Key] = element.Value;
}
}
else
{
// set in ref document that was not found
value["$missing"] = true;
}
}
}
}
/// <summary> /// Abstract method that must be implement for index seek/scan - Returns IndexNodes that match with index /// </summary> public abstract IEnumerable <IndexNode> Execute(IndexService indexer, CollectionIndex index);
/// <summary>
/// Internal implementation of insert a document
/// </summary>
private void InsertDocument(Snapshot snapshot, BsonDocument doc, BsonAutoId autoId, IndexService indexer, DataService data)
{
// if no _id, use AutoId
if (!doc.TryGetValue("_id", out var id))
{
doc["_id"] = id =
autoId == BsonAutoId.ObjectId ? new BsonValue(ObjectId.NewObjectId()) :
autoId == BsonAutoId.Guid ? new BsonValue(Guid.NewGuid()) :
this.GetSequence(snapshot, autoId);
}
else if (id.IsNumber)
{
// update memory sequence of numeric _id
this.SetSequence(snapshot, id);
}
// test if _id is a valid type
if (id.IsNull || id.IsMinValue || id.IsMaxValue)
{
throw LiteException.InvalidDataType("_id", id);
}
// storage in data pages - returns dataBlock address
var dataBlock = data.Insert(doc);
IndexNode last = null;
// for each index, insert new IndexNode
foreach (var index in snapshot.CollectionPage.GetCollectionIndexes())
{
// for each index, get all keys (supports multi-key) - gets distinct values only
// if index are unique, get single key only
var keys = index.BsonExpr.Execute(doc, _header.Pragmas.Collation);
// do a loop with all keys (multi-key supported)
foreach (var key in keys)
{
// insert node
var node = indexer.AddNode(index, key, dataBlock, last);
last = node;
}
}
}
private IEnumerable <IndexNode> ExecuteStartsWith(IndexService indexer, CollectionIndex index)
{
// find first indexNode
var first = indexer.Find(index, _startsWith, true, this.Order);
var node = first;
// if collection exists but are empty
if (first == null)
{
yield break;
}
// first, go backward to get all same values
while (node != null)
{
// if current node are edges exit while
if (node.Key.IsMinValue || node.Key.IsMaxValue)
{
break;
}
var valueString = node.Key.IsString ? node.Key.AsString : node.Key.ToString();
if (_equals ?
valueString.Equals(_startsWith, StringComparison.OrdinalIgnoreCase) :
valueString.StartsWith(_startsWith, StringComparison.OrdinalIgnoreCase))
{
// must still testing SqlLike method for rest of pattern - only if exists more to test (avoid slow SqlLike test)
if ((_testSqlLike == false) ||
(_testSqlLike == true && valueString.SqlLike(_pattern) == true))
{
yield return(node);
}
}
else
{
break;
}
node = indexer.GetNode(node.GetNextPrev(0, -this.Order));
}
// move fordward
node = indexer.GetNode(first.GetNextPrev(0, this.Order));
while (node != null)
{
// if current node are edges exit while
if (node.Key.IsMinValue || node.Key.IsMaxValue)
{
break;
}
var valueString = node.Key.IsString ? node.Key.AsString : node.Key.ToString();
if (_equals ?
valueString.Equals(_pattern, StringComparison.OrdinalIgnoreCase) :
valueString.StartsWith(_startsWith, StringComparison.OrdinalIgnoreCase))
{
// must still testing SqlLike method for rest of pattern - only if exists more to test (avoid slow SqlLike test)
if (node.DataBlock.IsEmpty == false &&
((_testSqlLike == false) ||
(_testSqlLike == true && valueString.SqlLike(_pattern) == true)))
{
yield return(node);
}
}
else
{
break;
}
// first, go backward to get all same values
node = indexer.GetNode(node.GetNextPrev(0, this.Order));
}
}
private IEnumerable <IndexNode> ExecuteLike(IndexService indexer, CollectionIndex index)
{
return(indexer
.FindAll(index, this.Order)
.Where(x => x.Key.IsString && x.Key.AsString.SqlLike(_pattern)));
}
/// <summary>
/// Implement internal update document
/// </summary>
private bool UpdateDocument(Snapshot snapshot, CollectionPage col, BsonDocument doc, IndexService indexer, DataService data)
{
// normalize id before find
var id = doc["_id"];
// validate id for null, min/max values
if (id.IsNull || id.IsMinValue || id.IsMaxValue)
{
throw LiteException.InvalidDataType("_id", id);
}
// find indexNode from pk index
var pkNode = indexer.Find(col.PK, id, false, LiteDB.Query.Ascending);
// if not found document, no updates
if (pkNode == null)
{
return(false);
}
// update data storage
data.Update(col, pkNode.DataBlock, doc);
// get all current non-pk index nodes from this data block (slot, key, nodePosition)
var oldKeys = indexer.GetNodeList(pkNode.NextNode)
.Select(x => new Tuple <byte, BsonValue, PageAddress>(x.Slot, x.Key, x.Position))
.ToArray();
// build a list of all new key index keys
var newKeys = new List <Tuple <byte, BsonValue, string> >();
foreach (var index in col.GetCollectionIndexes().Where(x => x.Name != "_id"))
{
// getting all keys from expression over document
var keys = index.BsonExpr.Execute(doc, _header.Pragmas.Collation);
foreach (var key in keys)
{
newKeys.Add(new Tuple <byte, BsonValue, string>(index.Slot, key, index.Name));
}
}
if (oldKeys.Length == 0 && newKeys.Count == 0)
{
return(true);
}
// get a list of all nodes that are in oldKeys but not in newKeys (must delete)
var toDelete = new HashSet <PageAddress>(oldKeys
.Where(x => newKeys.Any(n => n.Item1 == x.Item1 && n.Item2 == x.Item2) == false)
.Select(x => x.Item3));
// get a list of all keys that are not in oldKeys (must insert)
var toInsert = newKeys
.Where(x => oldKeys.Any(o => o.Item1 == x.Item1 && o.Item2 == x.Item2) == false)
.ToArray();
// if nothing to change, just exit
if (toDelete.Count == 0 && toInsert.Length == 0)
{
return(true);
}
// delete nodes and return last keeped node in list
var last = indexer.DeleteList(pkNode.Position, toDelete);
// now, insert all new nodes
foreach (var elem in toInsert)
{
var index = col.GetCollectionIndex(elem.Item3);
last = indexer.AddNode(index, elem.Item2, pkNode.DataBlock, last);
}
return(true);
}
public override IEnumerable <IndexNode> Execute(IndexService indexer, CollectionIndex index)
{
// if order are desc, swap start/end values
var start = this.Order == Query.Ascending ? _start : _end;
var end = this.Order == Query.Ascending ? _end : _start;
var startEquals = this.Order == Query.Ascending ? _startEquals : _endEquals;
var endEquals = this.Order == Query.Ascending ? _endEquals : _startEquals;
// find first indexNode (or get from head/tail if Min/Max value)
var first =
start.Type == BsonType.MinValue ? indexer.GetNode(index.Head) :
start.Type == BsonType.MaxValue ? indexer.GetNode(index.Tail) :
indexer.Find(index, start, true, this.Order);
var node = first;
// if startsEquals, return all equals value from start linked list
if (startEquals && node != null)
{
// going backward in same value list to get first value
while (!node.GetNextPrev(0, -this.Order).IsEmpty&& ((node = indexer.GetNode(node.GetNextPrev(0, -this.Order))).Key.CompareTo(start) == 0))
{
if (node.Key.IsMinValue || node.Key.IsMaxValue)
{
break;
}
yield return(node);
}
node = first;
}
// returns (or not) equals start value
while (node != null)
{
var diff = node.Key.CompareTo(start);
// if current value are not equals start, go out this loop
if (diff != 0)
{
break;
}
if (startEquals && !(node.Key.IsMinValue || node.Key.IsMaxValue))
{
yield return(node);
}
node = indexer.GetNode(node.GetNextPrev(0, this.Order));
}
// navigate using next[0] do next node - if less or equals returns
while (node != null)
{
var diff = node.Key.CompareTo(end);
if (endEquals && diff == 0 && !(node.Key.IsMinValue || node.Key.IsMaxValue))
{
yield return(node);
}
else if (diff == -this.Order && !(node.Key.IsMinValue || node.Key.IsMaxValue))
{
yield return(node);
}
else
{
break;
}
node = indexer.GetNode(node.GetNextPrev(0, this.Order));
}
}
/// <summary>
/// Create a new index (or do nothing if already exists) to a collection/field
/// </summary>
public bool EnsureIndex(string collection, string name, BsonExpression expression, bool unique)
{
if (collection.IsNullOrWhiteSpace())
{
throw new ArgumentNullException(nameof(collection));
}
if (name.IsNullOrWhiteSpace())
{
throw new ArgumentNullException(nameof(name));
}
if (expression == null)
{
throw new ArgumentNullException(nameof(expression));
}
if (expression.IsIndexable == false)
{
throw new ArgumentException("Index expressions must contains at least one document field. Used methods must be immutable. Parameters are not supported.", nameof(expression));
}
if (name.Length > INDEX_NAME_MAX_LENGTH)
{
throw LiteException.InvalidIndexName(name, collection, "MaxLength = " + INDEX_NAME_MAX_LENGTH);
}
if (!name.IsWord())
{
throw LiteException.InvalidIndexName(name, collection, "Use only [a-Z$_]");
}
if (name.StartsWith("$"))
{
throw LiteException.InvalidIndexName(name, collection, "Index name can't starts with `$`");
}
if (name == "_id")
{
return(false); // always exists
}
return(this.AutoTransaction(transaction =>
{
var snapshot = transaction.CreateSnapshot(LockMode.Write, collection, true);
var col = snapshot.CollectionPage;
var indexer = new IndexService(snapshot);
var data = new DataService(snapshot);
// check if index already exists
var current = col.GetCollectionIndex(name);
// if already exists, just exit
if (current != null)
{
// but if expression are different, throw error
if (current.Expression != expression.Source)
{
throw LiteException.IndexAlreadyExist(name);
}
return false;
}
LOG($"create index `{collection}.{name}`", "COMMAND");
// create index head
var index = indexer.CreateIndex(name, expression.Source, unique);
var count = 0u;
// read all objects (read from PK index)
foreach (var pkNode in new IndexAll("_id", LiteDB.Query.Ascending).Run(col, indexer))
{
using (var reader = new BufferReader(data.Read(pkNode.DataBlock)))
{
var doc = reader.ReadDocument(expression.Fields);
// first/last node in this document that will be added
IndexNode last = null;
IndexNode first = null;
// get values from expression in document
var keys = expression.Execute(doc);
// adding index node for each value
foreach (var key in keys)
{
// when index key is an array, get items inside array.
// valid only for first level (if this items are another array, this arrays will be indexed as array)
if (key.IsArray)
{
var arr = key.AsArray;
foreach (var itemKey in arr)
{
// insert new index node
var node = indexer.AddNode(index, itemKey, pkNode.DataBlock, last, _flipCoin);
if (first == null)
{
first = node;
}
last = node;
count++;
}
}
else
{
// insert new index node
var node = indexer.AddNode(index, key, pkNode.DataBlock, last, _flipCoin);
if (first == null)
{
first = node;
}
last = node;
count++;
}
}
// fix single linked-list in pkNode
if (first != null)
{
last.SetNextNode(pkNode.NextNode);
pkNode.SetNextNode(first.Position);
}
}
transaction.Safepoint();
}
index.KeyCount = count;
return true;
}));
}
public IndexLookup(IndexService indexer, string name)
{
_indexer = indexer;
_name = name;
}
public override IEnumerable <IndexNode> Execute(IndexService indexer, CollectionIndex index)
{
return(indexer
.FindAll(index, this.Order)
.Where(i => _func(i.Key)));
}