public TreeSystemStack(TreeSystemTransaction ts)
{
this.ts = ts;
stackSize = 0;
stack = new long[StackFrameSize*13];
currentLeaf = null;
currentLeafKey = null;
leafOffset = 0;
}
public TreeSystemStack(TreeSystemTransaction ts)
{
this.ts = ts;
stackSize = 0;
stack = new long[StackFrameSize * 13];
currentLeaf = null;
currentLeafKey = null;
leafOffset = 0;
}
public HeapTreeLeaf(TreeSystemTransaction transaction, NodeId nodeId, TreeLeaf toCopy, int capacity)
{
this.nodeId = nodeId;
size = toCopy.Length;
this.transaction = transaction;
// Copy the data into an array in this leaf.
data = new byte[capacity];
toCopy.Read(0, data, 0, size);
}
public void AddSpaceAfter(Key key, long spaceToAdd)
{
while (spaceToAdd > 0)
{
// Create an empty sparse node
TreeLeaf emptyLeaf = CreateSparseLeaf(key, 0, spaceToAdd);
InsertLeaf(key, emptyLeaf, false);
spaceToAdd -= emptyLeaf.Length;
}
}
private void UnfreezeStack()
{
StackFrame frame = StackEnd(0);
NodeId oldChildNodeId = frame.NodeId;
// If the leaf ref isn't frozen then we exit early
if (!IsFrozen(oldChildNodeId))
{
return;
}
TreeLeaf leaf = (TreeLeaf)UnfreezeNode(FetchNode(oldChildNodeId));
NodeId newChildNodeId = leaf.Id;
frame.NodeId = newChildNodeId;
currentLeaf = leaf;
// NOTE: Setting current_leaf here does not change the key of the node
// so we don't need to update current_leaf_key.
// Walk the rest of the stack from the end
int sz = FrameCount;
for (int i = 1; i < sz; ++i)
{
int changedChildIndex = frame.ChildIndex;
frame = StackEnd(i);
NodeId oldBranchId = frame.NodeId;
TreeBranch branch = (TreeBranch)UnfreezeNode(FetchNode(oldBranchId));
// Get the child_i from the stack,
branch.SetChild(newChildNodeId, changedChildIndex);
// Change the stack entry
frame.NodeId = branch.Id;
newChildNodeId = branch.Id;
}
// Set the new root node ref
RootNodeId = newChildNodeId;
}
public void WriteLeafOnly(Key key)
{
// Get the stack frame for the last entry.
StackFrame frame = StackEnd(0);
// The leaf
NodeId leafId = frame.NodeId;
// Write it out
NodeId newId = WriteNode(leafId);
// If new_ref = leaf_ref, then we didn't write a new node
if (newId.Equals(leafId))
{
return;
}
// Otherwise, update the references,
frame.NodeId = newId;
currentLeaf = (TreeLeaf)FetchNode(newId);
// Walk back up the stack and update the ref as necessary
int sz = FrameCount;
for (int i = 1; i < sz; ++i)
{
// Get the child_i from the stack,
int changedChildIndex = frame.ChildIndex;
frame = StackEnd(i);
NodeId oldBranchId = frame.NodeId;
TreeBranch branch = (TreeBranch)UnfreezeNode(FetchNode(oldBranchId));
branch.SetChild(newId, changedChildIndex);
// Change the stack entry
newId = branch.Id;
frame.NodeId = newId;
}
// Set the new root node ref
RootNodeId = newId;
}
public void SplitLeaf(Key key, long position)
{
UnfreezeStack();
TreeLeaf sourceLeaf = CurrentLeaf;
int splitPoint = LeafOffset;
// The amount of data we are copying from the current key.
int amount = sourceLeaf.Length - splitPoint;
// Create a new empty node
TreeLeaf emptyLeaf = CreateLeaf(key);
emptyLeaf.SetLength(amount);
// Copy the data at the end of the leaf into a buffer
byte[] buf = new byte[amount];
sourceLeaf.Read(splitPoint, buf, 0, amount);
// And write it out to the new leaf
emptyLeaf.Write(0, buf, 0, amount);
// Set the new size of the node
sourceLeaf.SetLength(splitPoint);
// Update the stack properties
UpdateStackProperties(-amount);
// And insert the new leaf after
InsertLeaf(key, emptyLeaf, false);
}
public void WriteLeafOnly(Key key)
{
// Get the stack frame for the last entry.
StackFrame frame = StackEnd(0);
// The leaf
NodeId leafId = frame.NodeId;
// Write it out
NodeId newId = WriteNode(leafId);
// If new_ref = leaf_ref, then we didn't write a new node
if (newId.Equals(leafId))
return;
// Otherwise, update the references,
frame.NodeId = newId;
currentLeaf = (TreeLeaf) FetchNode(newId);
// Walk back up the stack and update the ref as necessary
int sz = FrameCount;
for (int i = 1; i < sz; ++i) {
// Get the child_i from the stack,
int changedChildIndex = frame.ChildIndex;
frame = StackEnd(i);
NodeId oldBranchId = frame.NodeId;
TreeBranch branch = (TreeBranch) UnfreezeNode(FetchNode(oldBranchId));
branch.SetChild(newId, changedChildIndex);
// Change the stack entry
newId = branch.Id;
frame.NodeId = newId;
}
// Set the new root node ref
RootNodeId = newId;
}
public long Create()
{
if (initialized)
{
throw new InvalidOperationException("This tree store is already initialized.");
}
// Temporary node heap for creating a starting database
TreeNodeHeap nodeHeap = new TreeNodeHeap(17, 4 * 1024 * 1024);
// Write a root node to the store,
// Create an empty head node
TreeLeaf headLeaf = nodeHeap.CreateLeaf(null, Key.Head, 256);
// Insert a tree identification pattern
headLeaf.Write(0, new byte[] { 1, 1, 1, 1 }, 0, 4);
// Create an empty tail node
TreeLeaf tailLeaf = nodeHeap.CreateLeaf(null, Key.Tail, 256);
// Insert a tree identification pattern
tailLeaf.Write(0, new byte[] { 1, 1, 1, 1 }, 0, 4);
// The write sequence,
TreeWrite seq = new TreeWrite();
seq.NodeWrite(headLeaf);
seq.NodeWrite(tailLeaf);
IList <NodeId> refs = Persist(seq);
// Create a branch,
TreeBranch rootBranch = nodeHeap.CreateBranch(null, MaxBranchSize);
rootBranch.Set(refs[0], 4, Key.Tail, refs[1], 4);
seq = new TreeWrite();
seq.NodeWrite(rootBranch);
refs = Persist(seq);
// The written root node reference,
NodeId rootId = refs[0];
// Delete the head and tail leaf, and the root branch
nodeHeap.Delete(headLeaf.Id);
nodeHeap.Delete(tailLeaf.Id);
nodeHeap.Delete(rootBranch.Id);
// Write this version info to the store,
long versionId = WriteSingleVersionInfo(1, rootId, new List <NodeId>(0));
// Make a first version
VersionInfo versionInfo = new VersionInfo(1, rootId, versionId);
versions.Add(versionInfo);
// Flush this to the version list
IAreaWriter versionList = nodeStore.CreateArea(64);
versionList.WriteInt4(0x01433);
versionList.WriteInt4(1);
versionList.WriteInt8(versionId);
versionList.Finish();
// Get the versions id
long versionListId = versionList.Id;
// The final header
IAreaWriter header = nodeStore.CreateArea(64);
header.WriteInt4(0x09391); // The magic value,
header.WriteInt4(1); // The version
header.WriteInt8(versionListId);
header.Finish();
// Set up the internal variables,
headerId = header.Id;
initialized = true;
// And return the header reference
return(headerId);
}
public void SetupForPosition(Key key, long posit)
{
// If the current leaf is set
if (currentLeaf != null)
{
StackFrame frame = StackEnd(0);
long leafStart = frame.Offset;
long leafEnd = leafStart + currentLeaf.Length;
// If the position is at the leaf end, or if the keys aren't equal, we
// need to reset the stack. This ensures that we correctly place the
// pointer.
if (!key.Equals(Key.Tail) &&
(posit == leafEnd || !key.Equals(currentLeafKey)))
{
StackClear();
currentLeaf = null;
currentLeafKey = null;
}
else
{
// Check whether the position is within the bounds of the current leaf
// If 'posit' is within this leaf
if (posit >= leafStart && posit < leafEnd)
{
// If the position is within the current leaf, set up the internal
// vars as necessary.
leafOffset = (int)(posit - leafStart);
return;
}
// If it's not, we reset the stack and start fresh,
StackClear();
currentLeaf = null;
currentLeafKey = null;
}
}
// ISSUE: It appears looking at the code above, the stack will always be
// empty and current_leaf will always be null if we get here.
// If the stack is empty, push the root node,
if (StackEmpty)
{
// Push the root node onto the top of the stack.
StackPush(-1, 0, RootNodeId);
// Set up the current_leaf_key to the default value
currentLeafKey = Key.Head;
}
// Otherwise, we need to setup by querying the BTree.
while (true)
{
if (StackEmpty)
{
throw new ApplicationException("Position out of bounds. p = " + posit);
}
// Pop the last stack frame,
StackFrame frame = StackPop();
NodeId nodePointer = frame.NodeId;
long leftSideOffset = frame.Offset;
int nodeChildIndex = frame.ChildIndex;
// Relative offset within this node
long relativeOffset = posit - leftSideOffset;
// If the node is not on the heap,
if (!IsHeapNode(nodePointer))
{
// The node is not on the heap. We optimize here.
// If we know the node is going to be a leaf node, we set up a
// temporary leaf node object with as much information as we know.
// Check if we know this is a leaf
int treeHeight = TreeHeight;
if (treeHeight != -1 &&
(stackSize / StackFrameSize) + 1 == treeHeight)
{
// Fetch the parent node,
frame = StackEnd(0);
NodeId twigNodePointer = frame.NodeId;
TreeBranch twig = (TreeBranch)FetchNode(twigNodePointer);
long leafSize =
twig.GetChildLeafElementCount(nodeChildIndex);
// This object holds off fetching the contents of the leaf node
// unless it's absolutely required.
TreeLeaf leaf =
new PlaceholderLeaf(ts, nodePointer, (int)leafSize);
currentLeaf = leaf;
StackPush(nodeChildIndex, leftSideOffset, nodePointer);
// Set up the leaf offset and return
leafOffset = (int)relativeOffset;
return;
}
}
// Fetch the node
ITreeNode node = FetchNode(nodePointer);
if (node is TreeLeaf)
{
// Node is a leaf node
TreeLeaf leaf = (TreeLeaf)node;
currentLeaf = leaf;
StackPush(nodeChildIndex, leftSideOffset, nodePointer);
// Set up the leaf offset and return
leafOffset = (int)relativeOffset;
// Update the tree_height value,
TreeHeight = stackSize / StackFrameSize;
return;
}
// Node is a branch node
TreeBranch branch = (TreeBranch)node;
int childIndex = branch.IndexOfChild(key, relativeOffset);
if (childIndex != -1)
{
// Push the current details,
StackPush(nodeChildIndex, leftSideOffset, nodePointer);
// Found child so push the details
StackPush(childIndex,
branch.GetChildOffset(childIndex) + leftSideOffset,
branch.GetChild(childIndex));
// Set up the left key
if (childIndex > 0)
{
currentLeafKey = branch.GetKey(childIndex);
}
}
} // while (true)
}
public IList <NodeId> Persist(TreeWrite write)
{
try {
nodeStore.LockForWrite();
IList <ITreeNode> allBranches = write.BranchNodes;
IList <ITreeNode> allLeafs = write.LeafNodes;
List <ITreeNode> nodes = new List <ITreeNode>(allBranches.Count + allLeafs.Count);
nodes.AddRange(allBranches);
nodes.AddRange(allLeafs);
// The list of nodes to be allocated,
int sz = nodes.Count;
// The list of allocated referenced for the nodes,
NodeId[] refs = new NodeId[sz];
// The list of area writers,
IAreaWriter[] writers = new IAreaWriter[sz];
// Allocate the space first,
for (int i = 0; i < sz; ++i)
{
ITreeNode node = nodes[i];
// Is it a branch node?
if (node is TreeBranch)
{
TreeBranch branch = (TreeBranch)node;
int ndsz = branch.NodeDataSize;
writers[i] = nodeStore.CreateArea(4 + 4 + (ndsz * 8));
}
// Otherwise, it must be a leaf node,
else
{
TreeLeaf leaf = (TreeLeaf)node;
int lfsz = leaf.Length;
writers[i] = nodeStore.CreateArea(12 + lfsz);
}
// Set the reference,
refs[i] = FromInt64StoreAddress(writers[i].Id);
}
// Now write out the data,
for (int i = 0; i < sz; ++i)
{
ITreeNode node = nodes[i];
// Is it a branch node?
if (node is TreeBranch)
{
TreeBranch branch = (TreeBranch)node;
// The number of children
int chsz = branch.ChildCount;
// For each child, if it's a heap node, look up the child id and
// reference map in the sequence and set the reference accordingly,
for (int o = 0; o < chsz; ++o)
{
NodeId childId = branch.GetChild(o);
if (childId.IsInMemory)
{
// The ref is currently on the heap, so adjust accordingly
int refId = write.LookupRef(i, o);
branch.SetChild(refs[refId], o);
}
}
// Write out the branch to the store
long[] nodeData = branch.NodeData;
int ndsz = branch.NodeDataSize;
IAreaWriter writer = writers[i];
writer.WriteInt2(StoreBranchType);
writer.WriteInt2(1); // version
writer.WriteInt4(ndsz);
for (int o = 0; o < ndsz; ++o)
{
writer.WriteInt8(nodeData[o]);
}
writer.Finish();
// Make this into a branch node and add to the cache,
branch = new TreeBranch(refs[i], nodeData, ndsz);
// Put this branch in the cache,
lock (branchCache) {
branchCache.Set(refs[i], branch);
}
}
// Otherwise, it must be a leaf node,
else
{
TreeLeaf leaf = (TreeLeaf)node;
IAreaWriter writer = writers[i];
writer.WriteInt2(StoreLeafType);
writer.WriteInt2(1); // version
writer.WriteInt4(1); // reference count
writer.WriteInt4(leaf.Length);
leaf.WriteTo(writer);
writer.Finish();
}
}
return(refs);
} finally {
nodeStore.UnlockForWrite();
}
}
public void InsertLeaf(Key newLeafKey, TreeLeaf newLeaf, bool before)
{
int leafSize = newLeaf.Length;
if (leafSize <= 0)
{
throw new ArgumentException("size <= 0");
}
// The current absolute position and key
Key newKey = newLeafKey;
// The frame at the end of the stack,
StackFrame frame = StackEnd(0);
object[] info;
object[] rInfo = new object[5];
Key leftKey;
long curAbsolutePos;
// If we are inserting the new leaf after,
if (!before)
{
info = new object[] {
currentLeaf.Id,
(long)currentLeaf.Length,
newLeafKey,
newLeaf.Id,
(long)newLeaf.Length
};
leftKey = null;
curAbsolutePos = frame.Offset + currentLeaf.Length;
}
// Otherwise we are inserting the new leaf before,
else
{
// If before and current_leaf key is different than new_leaf key, we
// generate an error
if (!currentLeafKey.Equals(newLeafKey))
{
throw new InvalidOperationException("Can't insert different new key before.");
}
info = new Object[] {
newLeaf.Id,
(long)newLeaf.Length,
currentLeafKey,
currentLeaf.Id,
(long)currentLeaf.Length
};
leftKey = newLeafKey;
curAbsolutePos = frame.Offset - 1;
}
bool insertTwoNodes = true;
int sz = FrameCount;
// Walk the stack from the end
for (int i = 1; i < sz; ++i)
{
// child_i is the previous frame's child_i
int childIndex = frame.ChildIndex;
frame = StackEnd(i);
// The child ref of this stack element
NodeId childId = frame.NodeId;
// Fetch it
TreeBranch branch = (TreeBranch)UnfreezeNode(FetchNode(childId));
// Do we have two nodes to insert into the branch?
if (insertTwoNodes)
{
TreeBranch insertBranch;
int insertIndex = childIndex;
// If the branch is full,
if (branch.IsFull)
{
// Create a new node,
TreeBranch leftBranch = branch;
TreeBranch rightBranch = CreateBranch();
// Split the branch,
Key midpointKey = leftBranch.MidPointKey;
// And move half of this branch into the new branch
leftBranch.MoveLastHalfInto(rightBranch);
// We split so we need to return a split flag,
rInfo[0] = leftBranch.Id;
rInfo[1] = leftBranch.LeafElementCount;
rInfo[2] = midpointKey;
rInfo[3] = rightBranch.Id;
rInfo[4] = rightBranch.LeafElementCount;
// Adjust insert_n and insert_branch
if (insertIndex >= leftBranch.ChildCount)
{
insertIndex -= leftBranch.ChildCount;
insertBranch = rightBranch;
rInfo[4] = (long)rInfo[4] + newLeaf.Length;
// If insert_n == 0, we change the midpoint value to the left
// key value,
if (insertIndex == 0 && leftKey != null)
{
rInfo[2] = leftKey;
leftKey = null;
}
}
else
{
insertBranch = leftBranch;
rInfo[1] = (long)rInfo[1] + newLeaf.Length;
}
}
// If it's not full,
else
{
insertBranch = branch;
rInfo[0] = insertBranch.Id;
insertTwoNodes = false;
}
// Insert the two children nodes
insertBranch.Insert((NodeId)info[0], (long)info[1],
(Key)info[2],
(NodeId)info[3], (long)info[4],
insertIndex);
// Copy r_nfo to nfo
for (int p = 0; p < rInfo.Length; ++p)
{
info[p] = rInfo[p];
}
// Adjust the left key reference if necessary
if (leftKey != null && insertIndex > 0)
{
insertBranch.SetKeyToLeft(leftKey, insertIndex);
leftKey = null;
}
}
else
{
branch.SetChild((NodeId)info[0], childIndex);
info[0] = branch.Id;
branch.SetChildLeafElementCount(
branch.GetChildLeafElementCount(childIndex) + leafSize, childIndex);
// Adjust the left key reference if necessary
if (leftKey != null && childIndex > 0)
{
branch.SetKeyToLeft(leftKey, childIndex);
leftKey = null;
}
}
} // For all elements in the stack,
// At the end, if we still have a split then we make a new root and
// adjust the stack accordingly
if (insertTwoNodes)
{
TreeBranch newRoot = CreateBranch();
newRoot.Set((NodeId)info[0], (long)info[1],
(Key)info[2],
(NodeId)info[3], (long)info[4]);
RootNodeId = newRoot.Id;
if (TreeHeight != -1)
{
TreeHeight = TreeHeight + 1;
}
}
else
{
RootNodeId = (NodeId)info[0];
}
// Now reset the position,
Reset();
SetupForPosition(newKey, curAbsolutePos);
}
public void InsertLeaf(Key newLeafKey, TreeLeaf newLeaf, bool before)
{
int leafSize = newLeaf.Length;
if (leafSize <= 0)
throw new ArgumentException("size <= 0");
// The current absolute position and key
Key newKey = newLeafKey;
// The frame at the end of the stack,
StackFrame frame = StackEnd(0);
object[] info;
object[] rInfo = new object[5];
Key leftKey;
long curAbsolutePos;
// If we are inserting the new leaf after,
if (!before) {
info = new object[] {
currentLeaf.Id,
(long) currentLeaf.Length,
newLeafKey,
newLeaf.Id,
(long) newLeaf.Length
};
leftKey = null;
curAbsolutePos = frame.Offset + currentLeaf.Length;
}
// Otherwise we are inserting the new leaf before,
else {
// If before and current_leaf key is different than new_leaf key, we
// generate an error
if (!currentLeafKey.Equals(newLeafKey))
throw new InvalidOperationException("Can't insert different new key before.");
info = new Object[] {
newLeaf.Id,
(long) newLeaf.Length,
currentLeafKey,
currentLeaf.Id,
(long) currentLeaf.Length
};
leftKey = newLeafKey;
curAbsolutePos = frame.Offset - 1;
}
bool insertTwoNodes = true;
int sz = FrameCount;
// Walk the stack from the end
for (int i = 1; i < sz; ++i) {
// child_i is the previous frame's child_i
int childIndex = frame.ChildIndex;
frame = StackEnd(i);
// The child ref of this stack element
NodeId childId = frame.NodeId;
// Fetch it
TreeBranch branch = (TreeBranch) UnfreezeNode(FetchNode(childId));
// Do we have two nodes to insert into the branch?
if (insertTwoNodes) {
TreeBranch insertBranch;
int insertIndex = childIndex;
// If the branch is full,
if (branch.IsFull) {
// Create a new node,
TreeBranch leftBranch = branch;
TreeBranch rightBranch = CreateBranch();
// Split the branch,
Key midpointKey = leftBranch.MidPointKey;
// And move half of this branch into the new branch
leftBranch.MoveLastHalfInto(rightBranch);
// We split so we need to return a split flag,
rInfo[0] = leftBranch.Id;
rInfo[1] = leftBranch.LeafElementCount;
rInfo[2] = midpointKey;
rInfo[3] = rightBranch.Id;
rInfo[4] = rightBranch.LeafElementCount;
// Adjust insert_n and insert_branch
if (insertIndex >= leftBranch.ChildCount) {
insertIndex -= leftBranch.ChildCount;
insertBranch = rightBranch;
rInfo[4] = (long) rInfo[4] + newLeaf.Length;
// If insert_n == 0, we change the midpoint value to the left
// key value,
if (insertIndex == 0 && leftKey != null) {
rInfo[2] = leftKey;
leftKey = null;
}
} else {
insertBranch = leftBranch;
rInfo[1] = (long) rInfo[1] + newLeaf.Length;
}
}
// If it's not full,
else {
insertBranch = branch;
rInfo[0] = insertBranch.Id;
insertTwoNodes = false;
}
// Insert the two children nodes
insertBranch.Insert((NodeId) info[0], (long) info[1],
(Key) info[2],
(NodeId) info[3], (long) info[4],
insertIndex);
// Copy r_nfo to nfo
for (int p = 0; p < rInfo.Length; ++p) {
info[p] = rInfo[p];
}
// Adjust the left key reference if necessary
if (leftKey != null && insertIndex > 0) {
insertBranch.SetKeyToLeft(leftKey, insertIndex);
leftKey = null;
}
} else {
branch.SetChild((NodeId) info[0], childIndex);
info[0] = branch.Id;
branch.SetChildLeafElementCount(
branch.GetChildLeafElementCount(childIndex) + leafSize, childIndex);
// Adjust the left key reference if necessary
if (leftKey != null && childIndex > 0) {
branch.SetKeyToLeft(leftKey, childIndex);
leftKey = null;
}
}
} // For all elements in the stack,
// At the end, if we still have a split then we make a new root and
// adjust the stack accordingly
if (insertTwoNodes) {
TreeBranch newRoot = CreateBranch();
newRoot.Set((NodeId) info[0], (long) info[1],
(Key) info[2],
(NodeId) info[3], (long) info[4]);
RootNodeId = newRoot.Id;
if (TreeHeight != -1) {
TreeHeight = TreeHeight + 1;
}
} else {
RootNodeId = (NodeId) info[0];
}
// Now reset the position,
Reset();
SetupForPosition(newKey, curAbsolutePos);
}
public void Reset()
{
StackClear();
currentLeaf = null;
currentLeafKey = null;
}
private void CopyDataTo(long position, DataFile targetDataFile, long targetPosition, long size)
{
// If transactions are the same (data is being copied within the same
// transaction context).
TreeSystemStack targetStack;
TreeSystemStack sourceStack;
// Keys
Key targetKey = targetDataFile.key;
Key sourceKey = key;
bool modifyPosOnShift = false;
if (targetDataFile.Transaction == Transaction)
{
// We set the source and target stack to the same
sourceStack = targetDataFile.stack;
targetStack = sourceStack;
// If same transaction and target_position is before the position we
// set the modify_pos_on_shift boolean. This will update the absolute
// position when data is copied.
modifyPosOnShift = (targetPosition <= position);
}
else
{
// Otherwise, set the target stack to the target file's stack
sourceStack = stack;
targetStack = targetDataFile.stack;
}
// Compact the key we are copying from, and in the destination,
transaction.CompactNodeKey(sourceKey);
targetDataFile.CompactNodeKey(targetKey);
// The process works as follows;
// 1. If we are not positioned at the start of a leaf, copy all data up
// to the next leaf to the target.
// 2. Split the target leaf at the new position if the leaf can be
// split into 2 leaf nodes.
// 3. Copy every full leaf to the target as a new leaf element.
// 4. If there is any remaining data to copy, insert it into the target.
// Set up for the position
sourceStack.SetupForPosition(sourceKey, position);
// If we aren't at the start of the leaf, then copy the data to the
// target.
int leafOff = sourceStack.LeafOffset;
if (leafOff > 0)
{
// We copy the remaining data in the leaf to the target
// The amount of data to copy from the leaf to the target
int to_copy = (int)Math.Min(size, sourceStack.LeafSize - leafOff);
if (to_copy > 0)
{
// Read into a buffer
byte[] buf = new byte[to_copy];
sourceStack.CurrentLeaf.Read(leafOff, buf, 0, to_copy);
// Make enough room to insert this data in the target
targetStack.ShiftData(targetKey, targetPosition, to_copy);
// Update the position if necessary
if (modifyPosOnShift)
{
position += to_copy;
}
// Write the data to the target stack
targetStack.WriteFrom(targetKey, targetPosition, buf, 0, to_copy);
// Increment the pointers
position += to_copy;
targetPosition += to_copy;
size -= to_copy;
}
}
// If this is true, the next iteration will use the byte buffer leaf copy
// routine. Set if a link to a node failed for whatever reason.
bool useByteBufferCopyForNext = false;
// The loop
while (size > 0)
{
// We now know we are at the start of a leaf with data left to copy.
sourceStack.SetupForPosition(sourceKey, position);
// Lets assert that
if (sourceStack.LeafOffset != 0)
{
throw new ApplicationException("Expected to be at the start of a leaf.");
}
// If the source is a heap node or we are copying less than the data
// that's in the leaf then we use the standard shift and write.
TreeLeaf currentLeaf = sourceStack.CurrentLeaf;
// Check the leaf size isn't 0
if (currentLeaf.Length <= 0)
{
throw new ApplicationException("Leaf is empty.");
}
// If the remaining copy is less than the size of the leaf we are
// copying from, we just do a byte array copy
if (useByteBufferCopyForNext || size < currentLeaf.Length)
{
// Standard copy through a byte[] buf,
useByteBufferCopyForNext = false;
int toCopy = (int)Math.Min(size, currentLeaf.Length);
// Read into a buffer
byte[] buf = new byte[toCopy];
currentLeaf.Read(0, buf, 0, toCopy);
// Make enough room in the target
targetStack.ShiftData(targetKey, targetPosition, toCopy);
if (modifyPosOnShift)
{
position += toCopy;
}
// Write the data and finish
targetStack.WriteFrom(targetKey, targetPosition, buf, 0, toCopy);
// Update pointers
position += toCopy;
targetPosition += toCopy;
size -= toCopy;
}
else
{
// We need to copy a complete leaf node,
// If the leaf is on the heap, write it out
if (transaction.IsHeapNode(currentLeaf.Id))
{
sourceStack.WriteLeafOnly(sourceKey);
// And update any vars
currentLeaf = sourceStack.CurrentLeaf;
}
// Ok, source current leaf isn't on the heap, and we are copying a
// complete leaf node, so we are elegible to play with pointers to
// copy the data.
targetStack.SetupForPosition(targetKey, targetPosition);
bool insertNextBefore = false;
// Does the target key exist?
bool targetKeyExists = targetStack.CurrentLeafKey.Equals(targetKey);
if (targetKeyExists)
{
// If the key exists, is target_position at the end of the span?
insertNextBefore = targetStack.LeafOffset < targetStack.CurrentLeaf.Length;
}
// If target isn't currently on a boundary
if (!targetStack.IsAtEndOfKeyData &&
targetStack.LeafOffset != 0)
{
// If we aren't on a boundary we need to split the target leaf
targetStack.SplitLeaf(targetKey, targetPosition);
}
// If the key exists we set up the position to the previous left
// to insert the new leaf, otherwise we set it up to the default
// position to insert.
// Copy the leaf,
// Try to link to this leaf
bool linkSuccessful = TreeSystem.LinkLeaf(targetKey, currentLeaf.Id);
// If the link was successful,
if (linkSuccessful)
{
// Insert the leaf into the tree
targetStack.InsertLeaf(targetKey, currentLeaf, insertNextBefore);
// Update the pointers
int copiedSize = currentLeaf.Length;
// Update if we inserting stuff before
if (modifyPosOnShift)
{
position += copiedSize;
}
position += copiedSize;
targetPosition += copiedSize;
size -= copiedSize;
}
// If the link was not successful,
else
{
// We loop back and use the byte buffer copy,
useByteBufferCopyForNext = true;
}
}
}
}
public void Reset()
{
StackClear();
currentLeaf = null;
currentLeafKey = null;
}
public void SetupForPosition(Key key, long posit)
{
// If the current leaf is set
if (currentLeaf != null) {
StackFrame frame = StackEnd(0);
long leafStart = frame.Offset;
long leafEnd = leafStart + currentLeaf.Length;
// If the position is at the leaf end, or if the keys aren't equal, we
// need to reset the stack. This ensures that we correctly place the
// pointer.
if (!key.Equals(Key.Tail) &&
(posit == leafEnd || !key.Equals(currentLeafKey))) {
StackClear();
currentLeaf = null;
currentLeafKey = null;
} else {
// Check whether the position is within the bounds of the current leaf
// If 'posit' is within this leaf
if (posit >= leafStart && posit < leafEnd) {
// If the position is within the current leaf, set up the internal
// vars as necessary.
leafOffset = (int) (posit - leafStart);
return;
}
// If it's not, we reset the stack and start fresh,
StackClear();
currentLeaf = null;
currentLeafKey = null;
}
}
// ISSUE: It appears looking at the code above, the stack will always be
// empty and current_leaf will always be null if we get here.
// If the stack is empty, push the root node,
if (StackEmpty) {
// Push the root node onto the top of the stack.
StackPush(-1, 0, RootNodeId);
// Set up the current_leaf_key to the default value
currentLeafKey = Key.Head;
}
// Otherwise, we need to setup by querying the BTree.
while (true) {
if (StackEmpty) {
throw new ApplicationException("Position out of bounds. p = " + posit);
}
// Pop the last stack frame,
StackFrame frame = StackPop();
NodeId nodePointer = frame.NodeId;
long leftSideOffset = frame.Offset;
int nodeChildIndex = frame.ChildIndex;
// Relative offset within this node
long relativeOffset = posit - leftSideOffset;
// If the node is not on the heap,
if (!IsHeapNode(nodePointer)) {
// The node is not on the heap. We optimize here.
// If we know the node is going to be a leaf node, we set up a
// temporary leaf node object with as much information as we know.
// Check if we know this is a leaf
int treeHeight = TreeHeight;
if (treeHeight != -1 &&
(stackSize/StackFrameSize) + 1 == treeHeight) {
// Fetch the parent node,
frame = StackEnd(0);
NodeId twigNodePointer = frame.NodeId;
TreeBranch twig = (TreeBranch) FetchNode(twigNodePointer);
long leafSize =
twig.GetChildLeafElementCount(nodeChildIndex);
// This object holds off fetching the contents of the leaf node
// unless it's absolutely required.
TreeLeaf leaf =
new PlaceholderLeaf(ts, nodePointer, (int) leafSize);
currentLeaf = leaf;
StackPush(nodeChildIndex, leftSideOffset, nodePointer);
// Set up the leaf offset and return
leafOffset = (int) relativeOffset;
return;
}
}
// Fetch the node
ITreeNode node = FetchNode(nodePointer);
if (node is TreeLeaf) {
// Node is a leaf node
TreeLeaf leaf = (TreeLeaf) node;
currentLeaf = leaf;
StackPush(nodeChildIndex, leftSideOffset, nodePointer);
// Set up the leaf offset and return
leafOffset = (int) relativeOffset;
// Update the tree_height value,
TreeHeight = stackSize/StackFrameSize;
return;
}
// Node is a branch node
TreeBranch branch = (TreeBranch) node;
int childIndex = branch.IndexOfChild(key, relativeOffset);
if (childIndex != -1) {
// Push the current details,
StackPush(nodeChildIndex, leftSideOffset, nodePointer);
// Found child so push the details
StackPush(childIndex,
branch.GetChildOffset(childIndex) + leftSideOffset,
branch.GetChild(childIndex));
// Set up the left key
if (childIndex > 0) {
currentLeafKey = branch.GetKey(childIndex);
}
}
} // while (true)
}
private void UnfreezeStack()
{
StackFrame frame = StackEnd(0);
NodeId oldChildNodeId = frame.NodeId;
// If the leaf ref isn't frozen then we exit early
if (!IsFrozen(oldChildNodeId)) {
return;
}
TreeLeaf leaf = (TreeLeaf) UnfreezeNode(FetchNode(oldChildNodeId));
NodeId newChildNodeId = leaf.Id;
frame.NodeId = newChildNodeId;
currentLeaf = leaf;
// NOTE: Setting current_leaf here does not change the key of the node
// so we don't need to update current_leaf_key.
// Walk the rest of the stack from the end
int sz = FrameCount;
for (int i = 1; i < sz; ++i) {
int changedChildIndex = frame.ChildIndex;
frame = StackEnd(i);
NodeId oldBranchId = frame.NodeId;
TreeBranch branch = (TreeBranch) UnfreezeNode(FetchNode(oldBranchId));
// Get the child_i from the stack,
branch.SetChild(newChildNodeId, changedChildIndex);
// Change the stack entry
frame.NodeId = branch.Id;
newChildNodeId = branch.Id;
}
// Set the new root node ref
RootNodeId = newChildNodeId;
}
internal HeapTreeLeaf(ITransaction tran, long nodeId, TreeLeaf toCopy, int maxCapacity)
: base()
{
this.nodeId = nodeId;
this.size = toCopy.Length;
this.tran = tran;
// Copy the data into an array in this leaf.
data = new byte[maxCapacity];
toCopy.Read(0, data, 0, size);
}