/// <summary>
/// Gets all node list from any index node (go forward and backward)
/// </summary>
public IEnumerable <IndexNode> GetNodeList(IndexNode node, bool includeInitial)
{
var next = node.NextNode;
var prev = node.PrevNode;
// returns some initial node
if (includeInitial)
{
yield return(node);
}
// go forward
while (next.IsEmpty == false)
{
var n = this.GetNode(next);
next = n.NextNode;
yield return(n);
}
// go backward
while (prev.IsEmpty == false)
{
var p = this.GetNode(prev);
prev = p.PrevNode;
yield return(p);
}
}
protected override void ReadContent(ByteReader reader)
{
this.Nodes = new Dictionary <ushort, IndexNode>(this.ItemCount);
for (var i = 0; i < this.ItemCount; i++)
{
var index = reader.ReadUInt16();
var levels = reader.ReadByte();
var node = new IndexNode(levels);
node.Page = this;
node.Position = new PageAddress(this.PageID, index);
node.Slot = reader.ReadByte();
node.PrevNode = reader.ReadPageAddress();
node.NextNode = reader.ReadPageAddress();
node.KeyLength = reader.ReadUInt16();
node.Key = reader.ReadBsonValue(node.KeyLength);
node.DataBlock = reader.ReadPageAddress();
for (var j = 0; j < node.Prev.Length; j++)
{
node.Prev[j] = reader.ReadPageAddress();
node.Next[j] = reader.ReadPageAddress();
}
this.Nodes.Add(node.Position.Index, node);
}
}
/// <summary>
/// Create a new index and returns head page address (skip list)
/// </summary>
public CollectionIndex CreateIndex(CollectionIndex index)
{
// get a new index page for first index page
var page = _pager.NewPage <IndexPage>();
// create a empty node with full max level
var node = new IndexNode(IndexNode.MAX_LEVEL_LENGTH)
{
Key = new IndexKey(null), Page = page
};
node.Position = new PageAddress(page.PageID, 0);
// add as first node
page.Nodes.Add(node.Position.Index, node);
// add/remove indexPage on freelist if has space
_pager.AddOrRemoveToFreeList(page.FreeBytes > BasePage.RESERVED_BYTES, page, index.Page, ref index.FreeIndexPageID);
// point the head node to this new node position
index.HeadNode = node.Position;
index.Page.IsDirty = true;
page.IsDirty = true;
return(index);
}
/// <summary>
/// Delete node from this page and update counter and free space
/// </summary>
public void DeleteNode(IndexNode node)
{
this.ItemCount--;
this.FreeBytes += node.Length;
_nodes.Remove(node.Position.Index);
}
/// <summary>
/// Add new index node into this page. Update counters and free space
/// </summary>
public void AddNode(IndexNode node)
{
var index = _nodes.NextIndex();
node.Position = new PageAddress(this.PageID, index);
this.ItemCount++;
this.FreeBytes -= node.Length;
_nodes.Add(index, node);
}
internal virtual void Delete(CollectionPage col, IndexNode node)
{
// read dataBlock
var dataBlock = this.Database.Data.Read(node.DataBlock, false);
// lets remove all indexes that point to this in dataBlock
foreach (var index in col.GetIndexes(true))
{
this.Database.Indexer.Delete(index, dataBlock.IndexRef[index.Slot]);
}
// remove object data
this.Database.Data.Delete(col, node.DataBlock);
}
/// <summary>
/// Insert a new node index inside an collection index. Flip coin to know level
/// </summary>
public IndexNode AddNode(CollectionIndex index, BsonValue key, IndexNode last)
{
var level = this.FlipCoin();
// set index collection with max-index level
if (level > index.MaxLevel)
{
index.MaxLevel = level;
_pager.SetDirty(index.Page);
}
// call AddNode with key value
return(this.AddNode(index, key, level, last));
}
/// <summary>
/// Go first/last occurence of this index value
/// </summary>
private IndexNode FindBoundary(CollectionIndex index, IndexNode cur, BsonValue value, int order, int level)
{
var last = cur;
while (cur.Key.CompareTo(value) == 0)
{
last = cur;
cur = this.GetNode(cur.NextPrev(0, order));
if (cur.IsHeadTail(index))
{
break;
}
}
return(last);
}
internal virtual void Delete(CollectionPage col, IndexNode node)
{
// read dataBlock
var dataBlock = _engine.Data.Read(node.DataBlock, false);
// lets remove all indexes that point to this in dataBlock
for (byte i = 0; i < col.Indexes.Length; i++)
{
var index = col.Indexes[i];
if (!index.IsEmpty)
{
_engine.Indexer.Delete(index, dataBlock.IndexRef[i]);
}
}
// remove object data
_engine.Data.Delete(col, node.DataBlock);
}
/// <summary>
/// Create a new index and returns head page address (skip list)
/// </summary>
public CollectionIndex CreateIndex(CollectionPage col)
{
// get index slot
var index = col.GetFreeIndex();
// get a new index page for first index page
var page = _pager.NewPage <IndexPage>();
// create a empty node with full max level
var head = new IndexNode(IndexNode.MAX_LEVEL_LENGTH)
{
Key = BsonValue.MinValue,
KeyLength = (ushort)BsonValue.MinValue.GetBytesCount(false),
Slot = (byte)index.Slot,
Page = page,
Position = new PageAddress(page.PageID, 0)
};
// add as first node
page.Nodes.Add(head.Position.Index, head);
// update freebytes + item count (for head)
page.UpdateItemCount();
// set index page as dirty
_pager.SetDirty(index.Page);
// add indexPage on freelist if has space
_pager.AddOrRemoveToFreeList(true, page, index.Page, ref index.FreeIndexPageID);
// point the head/tail node to this new node position
index.HeadNode = head.Position;
// insert tail node
var tail = this.AddNode(index, BsonValue.MaxValue, IndexNode.MAX_LEVEL_LENGTH, null);
index.TailNode = tail.Position;
return(index);
}
/// <summary>
/// Insert a new node index inside an collection index.
/// </summary>
private IndexNode AddNode(CollectionIndex index, BsonValue key, byte level)
{
// creating a new index node
var node = new IndexNode(level)
{
Key = key,
KeyLength = key.GetBytesCount()
};
if (node.KeyLength > MAX_INDEX_LENGTH)
{
throw LiteException.IndexKeyTooLong();
}
// get a free page to insert my index node
var page = _pager.GetFreePage <IndexPage>(index.FreeIndexPageID, node.Length);
node.Position = new PageAddress(page.PageID, page.Nodes.NextIndex());
node.Page = page;
// add index node to page
page.Nodes.Add(node.Position.Index, node);
// update freebytes + items count
page.UpdateItemCount();
// now, let's link my index node on right place
var cur = this.GetNode(index.HeadNode);
// scan from top left
for (var i = IndexNode.MAX_LEVEL_LENGTH - 1; i >= 0; i--)
{
// for(; <while_not_this>; <do_this>) { ... }
for (; cur.Next[i].IsEmpty == false; cur = this.GetNode(cur.Next[i]))
{
// read next node to compare
var diff = this.GetNode(cur.Next[i]).Key.CompareTo(key);
// if unique and diff = 0, throw index exception (must rollback transaction - others nodes can be dirty)
if (diff == 0 && index.Options.Unique)
{
throw LiteException.IndexDuplicateKey(index.Field, key);
}
if (diff == 1)
{
break;
}
}
if (i <= (level - 1)) // level == length
{
// cur = current (imediatte before - prev)
// node = new inserted node
// next = next node (where cur is poiting)
node.Next[i] = cur.Next[i];
node.Prev[i] = cur.Position;
cur.Next[i] = node.Position;
var next = this.GetNode(node.Next[i]);
if (next != null)
{
next.Prev[i] = node.Position;
next.Page.IsDirty = true;
}
cur.Page.IsDirty = true;
}
}
// add/remove indexPage on freelist if has space
_pager.AddOrRemoveToFreeList(page.FreeBytes > IndexPage.INDEX_RESERVED_BYTES, page, index.Page, ref index.FreeIndexPageID);
page.IsDirty = true;
return(node);
}
/// <summary>
/// Insert a new node index inside an collection index.
/// </summary>
private IndexNode AddNode(CollectionIndex index, BsonValue key, byte level, IndexNode last)
{
// calc key size
var keyLength = key.GetBytesCount(false);
if (keyLength > MAX_INDEX_LENGTH)
{
throw LiteException.IndexKeyTooLong();
}
// creating a new index node
var node = new IndexNode(level)
{
Key = key,
KeyLength = (ushort)keyLength,
Slot = (byte)index.Slot
};
// get a free page to insert my index node
var page = _pager.GetFreePage <IndexPage>(index.FreeIndexPageID, node.Length);
node.Position = new PageAddress(page.PageID, page.Nodes.NextIndex());
node.Page = page;
// add index node to page
page.Nodes.Add(node.Position.Index, node);
// update freebytes + items count
page.UpdateItemCount();
// now, let's link my index node on right place
var cur = this.GetNode(index.HeadNode);
// using as cache last
IndexNode cache = null;
// scan from top left
for (var i = IndexNode.MAX_LEVEL_LENGTH - 1; i >= 0; i--)
{
// get cache for last node
cache = cache != null && cache.Position.Equals(cur.Next[i]) ? cache : this.GetNode(cur.Next[i]);
// for(; <while_not_this>; <do_this>) { ... }
for (; cur.Next[i].IsEmpty == false; cur = cache)
{
// get cache for last node
cache = cache != null && cache.Position.Equals(cur.Next[i]) ? cache : this.GetNode(cur.Next[i]);
// read next node to compare
var diff = cache.Key.CompareTo(key);
// if unique and diff = 0, throw index exception (must rollback transaction - others nodes can be dirty)
if (diff == 0 && index.Unique)
{
throw LiteException.IndexDuplicateKey(index.Field, key);
}
if (diff == 1)
{
break;
}
}
if (i <= (level - 1)) // level == length
{
// cur = current (imediatte before - prev)
// node = new inserted node
// next = next node (where cur is poiting)
_pager.SetDirty(cur.Page);
node.Next[i] = cur.Next[i];
node.Prev[i] = cur.Position;
cur.Next[i] = node.Position;
var next = this.GetNode(node.Next[i]);
if (next != null)
{
next.Prev[i] = node.Position;
_pager.SetDirty(next.Page);
}
}
}
// add/remove indexPage on freelist if has space
_pager.AddOrRemoveToFreeList(page.FreeBytes > IndexPage.INDEX_RESERVED_BYTES, page, index.Page, ref index.FreeIndexPageID);
// if last node exists, create a double link list
if (last != null)
{
// link new node with last node
if (last.NextNode.IsEmpty == false)
{
// fix link pointer with has more nodes in list
var next = this.GetNode(last.NextNode);
next.PrevNode = node.Position;
last.NextNode = node.Position;
node.PrevNode = last.Position;
node.NextNode = next.Position;
_pager.SetDirty(next.Page);
}
else
{
last.NextNode = node.Position;
node.PrevNode = last.Position;
}
// set last node page as dirty
_pager.SetDirty(last.Page);
}
return(node);
}
/// <summary>
/// Insert a new node index inside an collection index. Flip coin to know level
/// </summary>
public IndexNode AddNode(CollectionIndex index, BsonValue key, IndexNode last)
{
// call AddNode with key value
return(this.AddNode(index, key, this.FlipCoin(), last));
}
/// <summary>
/// Insert a new node index inside a index. Use skip list
/// </summary>
public IndexNode AddNode(CollectionIndex index, object value)
{
// create persist value - used on key
var key = new IndexKey(value);
var level = this.FlipCoin();
// creating a new index node
var node = new IndexNode(level)
{
Key = key
};
// get a free page to insert my index node
var page = _pager.GetFreePage <IndexPage>(index.FreeIndexPageID, node.Length);
node.Position = new PageAddress(page.PageID, page.Nodes.NextIndex());
node.Page = page;
// add index node to page
page.Nodes.Add(node.Position.Index, node);
// now, let's link my index node on right place
var cur = this.GetNode(index.HeadNode);
// scan from top left
for (int i = IndexNode.MAX_LEVEL_LENGTH - 1; i >= 0; i--)
{
// for(; <while_not_this>; <do_this>) { ... }
for (; cur.Next[i].IsEmpty == false; cur = this.GetNode(cur.Next[i]))
{
// read next node to compare
var diff = this.GetNode(cur.Next[i]).Key.CompareTo(key);
// if unique and diff = 0, throw index exception (must rollback transaction - others nodes can be dirty)
if (diff == 0 && index.Unique)
{
throw new LiteException(string.Format("Cannot insert duplicate key in unique index '{0}'. The duplicate value is '{1}'.", index.Field, value));
}
if (diff == 1)
{
break;
}
}
if (i <= (level - 1)) // level == length
{
// cur = current (imediatte before - prev)
// node = new inserted node
// next = next node (where cur is poiting)
node.Next[i] = cur.Next[i];
node.Prev[i] = cur.Position;
cur.Next[i] = node.Position;
var next = this.GetNode(node.Next[i]);
if (next != null)
{
next.Prev[i] = node.Position;
next.Page.IsDirty = true;
}
cur.Page.IsDirty = true;
}
}
// add/remove indexPage on freelist if has space
_pager.AddOrRemoveToFreeList(page.FreeBytes > IndexPage.RESERVED_BYTES, page, index.Page, ref index.FreeIndexPageID);
page.IsDirty = true;
return(node);
}
/// <summary>
/// Wrtie any BsonValue. Use 1 byte for data type, 1 byte for length (optional), 0-255 bytes to value.
/// For document or array, use BufferWriter
/// </summary>
public static void WriteIndexKey(this BufferSlice buffer, BsonValue value, int offset)
{
ENSURE(IndexNode.GetKeyLength(value, true) <= MAX_INDEX_KEY_LENGTH, $"index key must have less than {MAX_INDEX_KEY_LENGTH} bytes");
if (value.IsString)
{
var str = value.AsString;
var strLength = (ushort)Encoding.UTF8.GetByteCount(str);
ExtendedLengthHelper.WriteLength(BsonType.String, strLength, out var typeByte, out var lengthByte);
buffer[offset++] = typeByte;
buffer[offset++] = lengthByte;
buffer.Write(str, offset);
}
else if (value.IsBinary)
{
var arr = value.AsBinary;
ExtendedLengthHelper.WriteLength(BsonType.Binary, (ushort)arr.Length, out var typeByte, out var lengthByte);
buffer[offset++] = typeByte;
buffer[offset++] = lengthByte;
buffer.Write(arr, offset);
}
else
{
buffer[offset++] = (byte)value.Type;
switch (value.Type)
{
case BsonType.Null:
case BsonType.MinValue:
case BsonType.MaxValue:
break;
case BsonType.Int32: buffer.Write(value.AsInt32, offset); break;
case BsonType.Int64: buffer.Write(value.AsInt64, offset); break;
case BsonType.Double: buffer.Write(value.AsDouble, offset); break;
case BsonType.Decimal: buffer.Write(value.AsDecimal, offset); break;
case BsonType.Document:
using (var w = new BufferWriter(buffer))
{
w.Skip(offset); // skip offset from buffer
w.WriteDocument(value.AsDocument, true);
}
break;
case BsonType.Array:
using (var w = new BufferWriter(buffer))
{
w.Skip(offset); // skip offset from buffer
w.WriteArray(value.AsArray, true);
}
break;
case BsonType.ObjectId: buffer.Write(value.AsObjectId, offset); break;
case BsonType.Guid: buffer.Write(value.AsGuid, offset); break;
case BsonType.Boolean: buffer[offset] = (value.AsBoolean) ? (byte)1 : (byte)0; break;
case BsonType.DateTime: buffer.Write(value.AsDateTime, offset); break;
default: throw new NotImplementedException();
}
}
}