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insert.go
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insert.go
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package mkvs
import (
"bytes"
"context"
"fmt"
"github.com/oasisprotocol/oasis-core/go/storage/mkvs/node"
)
// Implements Tree.
func (t *tree) Insert(ctx context.Context, key, value []byte) error {
if value == nil {
value = []byte{}
}
t.cache.Lock()
defer t.cache.Unlock()
if t.cache.isClosed() {
return ErrClosed
}
// Remember where the path from root to target node ends (will end).
t.cache.markPosition()
var result insertResult
result, err := t.doInsert(ctx, t.cache.pendingRoot, 0, key, value, 0)
if err != nil {
return err
}
// Update the pending write log.
if !t.withoutWriteLog {
entry := t.pendingWriteLog[node.ToMapKey(key)]
if entry == nil {
t.pendingWriteLog[node.ToMapKey(key)] = &pendingEntry{
key: key,
value: value,
existed: result.existed,
insertedLeaf: result.insertedLeaf,
}
} else {
entry.value = value
}
}
t.cache.setPendingRoot(result.newRoot)
return nil
}
type insertResult struct {
newRoot *node.Pointer
insertedLeaf *node.Pointer
existed bool
}
func (t *tree) doInsert(
ctx context.Context,
ptr *node.Pointer,
bitDepth node.Depth,
key node.Key,
val []byte,
depth node.Depth,
) (insertResult, error) {
if ctx.Err() != nil {
return insertResult{}, ctx.Err()
}
// Dereference the node, possibly making a remote request.
nd, err := t.cache.derefNodePtr(ctx, ptr, t.newFetcherSyncGet(key, false))
if err != nil {
return insertResult{}, err
}
_, keyRemainder := key.Split(bitDepth, key.BitLength())
switch n := nd.(type) {
case nil:
// Insert into nil node, create a new leaf node.
newLeaf := t.cache.newLeafNode(key, val)
result := insertResult{
newRoot: newLeaf,
insertedLeaf: newLeaf,
existed: false,
}
return result, nil
case *node.InternalNode:
cpLength := n.Label.CommonPrefixLen(n.LabelBitLength, keyRemainder, key.BitLength()-bitDepth)
var result insertResult
if cpLength == n.LabelBitLength {
bitLength := bitDepth + n.LabelBitLength
// The current part of key matched the node's Label. Do recursion.
if key.BitLength() == bitLength {
// Key to insert ends exactly at this node. Add it to the
// existing internal node as LeafNode.
result, err = t.doInsert(ctx, n.LeafNode, bitLength, key, val, depth)
} else if key.GetBit(bitLength) {
// Insert recursively based on the bit value.
result, err = t.doInsert(ctx, n.Right, bitLength, key, val, depth+1)
} else {
result, err = t.doInsert(ctx, n.Left, bitLength, key, val, depth+1)
}
if err != nil {
return insertResult{}, err
}
if key.BitLength() == bitLength {
n.LeafNode = result.newRoot
} else if key.GetBit(bitLength) {
n.Right = result.newRoot
} else {
n.Left = result.newRoot
}
if !n.LeafNode.IsClean() || !n.Left.IsClean() || !n.Right.IsClean() {
if n.Clean {
// Node was clean so old node is eligible for removal.
t.pendingRemovedNodes = append(t.pendingRemovedNodes, n.ExtractUnchecked())
}
n.Clean = false
ptr.Clean = false
// No longer eligible for eviction as it is dirty.
t.cache.rollbackNode(ptr)
}
result.newRoot = ptr
return result, nil
}
// Key mismatches the label at position cpLength. Split the edge and
// insert new leaf.
labelPrefix, labelSuffix := n.Label.Split(cpLength, n.LabelBitLength)
n.Label = labelSuffix
n.LabelBitLength = n.LabelBitLength - cpLength
if n.Clean {
// Node was clean so old node is eligible for removal.
t.pendingRemovedNodes = append(t.pendingRemovedNodes, n.ExtractUnchecked())
}
n.Clean = false
ptr.Clean = false
// No longer eligible for eviction as it is dirty.
t.cache.rollbackNode(ptr)
newLeaf := t.cache.newLeafNode(key, val)
var leafNode, left, right *node.Pointer
if key.BitLength()-bitDepth == cpLength {
// The key is a prefix of existing path.
leafNode = newLeaf
if labelSuffix.GetBit(0) {
left = nil
right = ptr
} else {
left = ptr
right = nil
}
} else if keyRemainder.GetBit(cpLength) {
left = ptr
right = newLeaf
} else {
left = newLeaf
right = ptr
}
return insertResult{
newRoot: t.cache.newInternalNode(labelPrefix, cpLength, leafNode, left, right),
insertedLeaf: newLeaf,
existed: false,
}, nil
case *node.LeafNode:
// If the key matches, we can just update the value.
if n.Key.Equal(key) {
if bytes.Equal(n.Value, val) {
return insertResult{
newRoot: ptr,
insertedLeaf: ptr,
existed: true,
}, nil
}
if n.Clean {
// Node is dirty so old node is eligible for removal.
t.pendingRemovedNodes = append(t.pendingRemovedNodes, n.ExtractUnchecked())
}
n.Value = val
n.Clean = false
ptr.Clean = false
// No longer eligible for eviction as it is dirty.
t.cache.rollbackNode(ptr)
return insertResult{
newRoot: ptr,
insertedLeaf: ptr,
existed: true,
}, nil
}
var result insertResult
_, leafKeyRemainder := n.Key.Split(bitDepth, n.Key.BitLength())
cpLength := leafKeyRemainder.CommonPrefixLen(n.Key.BitLength()-bitDepth, keyRemainder, key.BitLength()-bitDepth)
// Key mismatches the label at position cpLength. Split the edge.
labelPrefix, _ := leafKeyRemainder.Split(cpLength, leafKeyRemainder.BitLength())
newLeaf := t.cache.newLeafNode(key, val)
result.insertedLeaf = newLeaf
var leafNode, left, right *node.Pointer
if key.BitLength()-bitDepth == cpLength {
// Inserted key is a prefix of the label.
leafNode = newLeaf
if leafKeyRemainder.GetBit(cpLength) {
left = nil
right = ptr
} else {
left = ptr
right = nil
}
} else if n.Key.BitLength()-bitDepth == cpLength {
// Label is a prefix of the inserted key.
leafNode = ptr
if keyRemainder.GetBit(cpLength) {
left = nil
right = newLeaf
} else {
left = newLeaf
right = nil
}
} else if keyRemainder.GetBit(cpLength) {
left = ptr
right = newLeaf
} else {
left = newLeaf
right = ptr
}
result.newRoot = t.cache.newInternalNode(labelPrefix, cpLength, leafNode, left, right)
return result, nil
default:
panic(fmt.Sprintf("mkvs: unknown node type: %+v", n))
}
}