mirror of
https://github.com/go-gitea/gitea
synced 2024-12-21 15:24:04 +01:00
b6a95a8cb3
* Dropped unused codekit config * Integrated dynamic and static bindata for public * Ignore public bindata * Add a general generate make task * Integrated flexible public assets into web command * Updated vendoring, added all missiong govendor deps * Made the linter happy with the bindata and dynamic code * Moved public bindata definition to modules directory * Ignoring the new bindata path now * Updated to the new public modules import path * Updated public bindata command and drop the new prefix
599 lines
16 KiB
Go
599 lines
16 KiB
Go
package bolt
|
|
|
|
import (
|
|
"bytes"
|
|
"fmt"
|
|
"sort"
|
|
"unsafe"
|
|
)
|
|
|
|
// node represents an in-memory, deserialized page.
|
|
type node struct {
|
|
bucket *Bucket
|
|
isLeaf bool
|
|
unbalanced bool
|
|
spilled bool
|
|
key []byte
|
|
pgid pgid
|
|
parent *node
|
|
children nodes
|
|
inodes inodes
|
|
}
|
|
|
|
// root returns the top-level node this node is attached to.
|
|
func (n *node) root() *node {
|
|
if n.parent == nil {
|
|
return n
|
|
}
|
|
return n.parent.root()
|
|
}
|
|
|
|
// minKeys returns the minimum number of inodes this node should have.
|
|
func (n *node) minKeys() int {
|
|
if n.isLeaf {
|
|
return 1
|
|
}
|
|
return 2
|
|
}
|
|
|
|
// size returns the size of the node after serialization.
|
|
func (n *node) size() int {
|
|
sz, elsz := pageHeaderSize, n.pageElementSize()
|
|
for i := 0; i < len(n.inodes); i++ {
|
|
item := &n.inodes[i]
|
|
sz += elsz + len(item.key) + len(item.value)
|
|
}
|
|
return sz
|
|
}
|
|
|
|
// sizeLessThan returns true if the node is less than a given size.
|
|
// This is an optimization to avoid calculating a large node when we only need
|
|
// to know if it fits inside a certain page size.
|
|
func (n *node) sizeLessThan(v int) bool {
|
|
sz, elsz := pageHeaderSize, n.pageElementSize()
|
|
for i := 0; i < len(n.inodes); i++ {
|
|
item := &n.inodes[i]
|
|
sz += elsz + len(item.key) + len(item.value)
|
|
if sz >= v {
|
|
return false
|
|
}
|
|
}
|
|
return true
|
|
}
|
|
|
|
// pageElementSize returns the size of each page element based on the type of node.
|
|
func (n *node) pageElementSize() int {
|
|
if n.isLeaf {
|
|
return leafPageElementSize
|
|
}
|
|
return branchPageElementSize
|
|
}
|
|
|
|
// childAt returns the child node at a given index.
|
|
func (n *node) childAt(index int) *node {
|
|
if n.isLeaf {
|
|
panic(fmt.Sprintf("invalid childAt(%d) on a leaf node", index))
|
|
}
|
|
return n.bucket.node(n.inodes[index].pgid, n)
|
|
}
|
|
|
|
// childIndex returns the index of a given child node.
|
|
func (n *node) childIndex(child *node) int {
|
|
index := sort.Search(len(n.inodes), func(i int) bool { return bytes.Compare(n.inodes[i].key, child.key) != -1 })
|
|
return index
|
|
}
|
|
|
|
// numChildren returns the number of children.
|
|
func (n *node) numChildren() int {
|
|
return len(n.inodes)
|
|
}
|
|
|
|
// nextSibling returns the next node with the same parent.
|
|
func (n *node) nextSibling() *node {
|
|
if n.parent == nil {
|
|
return nil
|
|
}
|
|
index := n.parent.childIndex(n)
|
|
if index >= n.parent.numChildren()-1 {
|
|
return nil
|
|
}
|
|
return n.parent.childAt(index + 1)
|
|
}
|
|
|
|
// prevSibling returns the previous node with the same parent.
|
|
func (n *node) prevSibling() *node {
|
|
if n.parent == nil {
|
|
return nil
|
|
}
|
|
index := n.parent.childIndex(n)
|
|
if index == 0 {
|
|
return nil
|
|
}
|
|
return n.parent.childAt(index - 1)
|
|
}
|
|
|
|
// put inserts a key/value.
|
|
func (n *node) put(oldKey, newKey, value []byte, pgid pgid, flags uint32) {
|
|
if pgid >= n.bucket.tx.meta.pgid {
|
|
panic(fmt.Sprintf("pgid (%d) above high water mark (%d)", pgid, n.bucket.tx.meta.pgid))
|
|
} else if len(oldKey) <= 0 {
|
|
panic("put: zero-length old key")
|
|
} else if len(newKey) <= 0 {
|
|
panic("put: zero-length new key")
|
|
}
|
|
|
|
// Find insertion index.
|
|
index := sort.Search(len(n.inodes), func(i int) bool { return bytes.Compare(n.inodes[i].key, oldKey) != -1 })
|
|
|
|
// Add capacity and shift nodes if we don't have an exact match and need to insert.
|
|
exact := (len(n.inodes) > 0 && index < len(n.inodes) && bytes.Equal(n.inodes[index].key, oldKey))
|
|
if !exact {
|
|
n.inodes = append(n.inodes, inode{})
|
|
copy(n.inodes[index+1:], n.inodes[index:])
|
|
}
|
|
|
|
inode := &n.inodes[index]
|
|
inode.flags = flags
|
|
inode.key = newKey
|
|
inode.value = value
|
|
inode.pgid = pgid
|
|
_assert(len(inode.key) > 0, "put: zero-length inode key")
|
|
}
|
|
|
|
// del removes a key from the node.
|
|
func (n *node) del(key []byte) {
|
|
// Find index of key.
|
|
index := sort.Search(len(n.inodes), func(i int) bool { return bytes.Compare(n.inodes[i].key, key) != -1 })
|
|
|
|
// Exit if the key isn't found.
|
|
if index >= len(n.inodes) || !bytes.Equal(n.inodes[index].key, key) {
|
|
return
|
|
}
|
|
|
|
// Delete inode from the node.
|
|
n.inodes = append(n.inodes[:index], n.inodes[index+1:]...)
|
|
|
|
// Mark the node as needing rebalancing.
|
|
n.unbalanced = true
|
|
}
|
|
|
|
// read initializes the node from a page.
|
|
func (n *node) read(p *page) {
|
|
n.pgid = p.id
|
|
n.isLeaf = ((p.flags & leafPageFlag) != 0)
|
|
n.inodes = make(inodes, int(p.count))
|
|
|
|
for i := 0; i < int(p.count); i++ {
|
|
inode := &n.inodes[i]
|
|
if n.isLeaf {
|
|
elem := p.leafPageElement(uint16(i))
|
|
inode.flags = elem.flags
|
|
inode.key = elem.key()
|
|
inode.value = elem.value()
|
|
} else {
|
|
elem := p.branchPageElement(uint16(i))
|
|
inode.pgid = elem.pgid
|
|
inode.key = elem.key()
|
|
}
|
|
_assert(len(inode.key) > 0, "read: zero-length inode key")
|
|
}
|
|
|
|
// Save first key so we can find the node in the parent when we spill.
|
|
if len(n.inodes) > 0 {
|
|
n.key = n.inodes[0].key
|
|
_assert(len(n.key) > 0, "read: zero-length node key")
|
|
} else {
|
|
n.key = nil
|
|
}
|
|
}
|
|
|
|
// write writes the items onto one or more pages.
|
|
func (n *node) write(p *page) {
|
|
// Initialize page.
|
|
if n.isLeaf {
|
|
p.flags |= leafPageFlag
|
|
} else {
|
|
p.flags |= branchPageFlag
|
|
}
|
|
|
|
if len(n.inodes) >= 0xFFFF {
|
|
panic(fmt.Sprintf("inode overflow: %d (pgid=%d)", len(n.inodes), p.id))
|
|
}
|
|
p.count = uint16(len(n.inodes))
|
|
|
|
// Loop over each item and write it to the page.
|
|
b := (*[maxAllocSize]byte)(unsafe.Pointer(&p.ptr))[n.pageElementSize()*len(n.inodes):]
|
|
for i, item := range n.inodes {
|
|
_assert(len(item.key) > 0, "write: zero-length inode key")
|
|
|
|
// Write the page element.
|
|
if n.isLeaf {
|
|
elem := p.leafPageElement(uint16(i))
|
|
elem.pos = uint32(uintptr(unsafe.Pointer(&b[0])) - uintptr(unsafe.Pointer(elem)))
|
|
elem.flags = item.flags
|
|
elem.ksize = uint32(len(item.key))
|
|
elem.vsize = uint32(len(item.value))
|
|
} else {
|
|
elem := p.branchPageElement(uint16(i))
|
|
elem.pos = uint32(uintptr(unsafe.Pointer(&b[0])) - uintptr(unsafe.Pointer(elem)))
|
|
elem.ksize = uint32(len(item.key))
|
|
elem.pgid = item.pgid
|
|
_assert(elem.pgid != p.id, "write: circular dependency occurred")
|
|
}
|
|
|
|
// If the length of key+value is larger than the max allocation size
|
|
// then we need to reallocate the byte array pointer.
|
|
//
|
|
// See: https://github.com/boltdb/bolt/pull/335
|
|
klen, vlen := len(item.key), len(item.value)
|
|
if len(b) < klen+vlen {
|
|
b = (*[maxAllocSize]byte)(unsafe.Pointer(&b[0]))[:]
|
|
}
|
|
|
|
// Write data for the element to the end of the page.
|
|
copy(b[0:], item.key)
|
|
b = b[klen:]
|
|
copy(b[0:], item.value)
|
|
b = b[vlen:]
|
|
}
|
|
|
|
// DEBUG ONLY: n.dump()
|
|
}
|
|
|
|
// split breaks up a node into multiple smaller nodes, if appropriate.
|
|
// This should only be called from the spill() function.
|
|
func (n *node) split(pageSize int) []*node {
|
|
var nodes []*node
|
|
|
|
node := n
|
|
for {
|
|
// Split node into two.
|
|
a, b := node.splitTwo(pageSize)
|
|
nodes = append(nodes, a)
|
|
|
|
// If we can't split then exit the loop.
|
|
if b == nil {
|
|
break
|
|
}
|
|
|
|
// Set node to b so it gets split on the next iteration.
|
|
node = b
|
|
}
|
|
|
|
return nodes
|
|
}
|
|
|
|
// splitTwo breaks up a node into two smaller nodes, if appropriate.
|
|
// This should only be called from the split() function.
|
|
func (n *node) splitTwo(pageSize int) (*node, *node) {
|
|
// Ignore the split if the page doesn't have at least enough nodes for
|
|
// two pages or if the nodes can fit in a single page.
|
|
if len(n.inodes) <= (minKeysPerPage*2) || n.sizeLessThan(pageSize) {
|
|
return n, nil
|
|
}
|
|
|
|
// Determine the threshold before starting a new node.
|
|
var fillPercent = n.bucket.FillPercent
|
|
if fillPercent < minFillPercent {
|
|
fillPercent = minFillPercent
|
|
} else if fillPercent > maxFillPercent {
|
|
fillPercent = maxFillPercent
|
|
}
|
|
threshold := int(float64(pageSize) * fillPercent)
|
|
|
|
// Determine split position and sizes of the two pages.
|
|
splitIndex, _ := n.splitIndex(threshold)
|
|
|
|
// Split node into two separate nodes.
|
|
// If there's no parent then we'll need to create one.
|
|
if n.parent == nil {
|
|
n.parent = &node{bucket: n.bucket, children: []*node{n}}
|
|
}
|
|
|
|
// Create a new node and add it to the parent.
|
|
next := &node{bucket: n.bucket, isLeaf: n.isLeaf, parent: n.parent}
|
|
n.parent.children = append(n.parent.children, next)
|
|
|
|
// Split inodes across two nodes.
|
|
next.inodes = n.inodes[splitIndex:]
|
|
n.inodes = n.inodes[:splitIndex]
|
|
|
|
// Update the statistics.
|
|
n.bucket.tx.stats.Split++
|
|
|
|
return n, next
|
|
}
|
|
|
|
// splitIndex finds the position where a page will fill a given threshold.
|
|
// It returns the index as well as the size of the first page.
|
|
// This is only be called from split().
|
|
func (n *node) splitIndex(threshold int) (index, sz int) {
|
|
sz = pageHeaderSize
|
|
|
|
// Loop until we only have the minimum number of keys required for the second page.
|
|
for i := 0; i < len(n.inodes)-minKeysPerPage; i++ {
|
|
index = i
|
|
inode := n.inodes[i]
|
|
elsize := n.pageElementSize() + len(inode.key) + len(inode.value)
|
|
|
|
// If we have at least the minimum number of keys and adding another
|
|
// node would put us over the threshold then exit and return.
|
|
if i >= minKeysPerPage && sz+elsize > threshold {
|
|
break
|
|
}
|
|
|
|
// Add the element size to the total size.
|
|
sz += elsize
|
|
}
|
|
|
|
return
|
|
}
|
|
|
|
// spill writes the nodes to dirty pages and splits nodes as it goes.
|
|
// Returns an error if dirty pages cannot be allocated.
|
|
func (n *node) spill() error {
|
|
var tx = n.bucket.tx
|
|
if n.spilled {
|
|
return nil
|
|
}
|
|
|
|
// Spill child nodes first. Child nodes can materialize sibling nodes in
|
|
// the case of split-merge so we cannot use a range loop. We have to check
|
|
// the children size on every loop iteration.
|
|
sort.Sort(n.children)
|
|
for i := 0; i < len(n.children); i++ {
|
|
if err := n.children[i].spill(); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
// We no longer need the child list because it's only used for spill tracking.
|
|
n.children = nil
|
|
|
|
// Split nodes into appropriate sizes. The first node will always be n.
|
|
var nodes = n.split(tx.db.pageSize)
|
|
for _, node := range nodes {
|
|
// Add node's page to the freelist if it's not new.
|
|
if node.pgid > 0 {
|
|
tx.db.freelist.free(tx.meta.txid, tx.page(node.pgid))
|
|
node.pgid = 0
|
|
}
|
|
|
|
// Allocate contiguous space for the node.
|
|
p, err := tx.allocate((node.size() / tx.db.pageSize) + 1)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
// Write the node.
|
|
if p.id >= tx.meta.pgid {
|
|
panic(fmt.Sprintf("pgid (%d) above high water mark (%d)", p.id, tx.meta.pgid))
|
|
}
|
|
node.pgid = p.id
|
|
node.write(p)
|
|
node.spilled = true
|
|
|
|
// Insert into parent inodes.
|
|
if node.parent != nil {
|
|
var key = node.key
|
|
if key == nil {
|
|
key = node.inodes[0].key
|
|
}
|
|
|
|
node.parent.put(key, node.inodes[0].key, nil, node.pgid, 0)
|
|
node.key = node.inodes[0].key
|
|
_assert(len(node.key) > 0, "spill: zero-length node key")
|
|
}
|
|
|
|
// Update the statistics.
|
|
tx.stats.Spill++
|
|
}
|
|
|
|
// If the root node split and created a new root then we need to spill that
|
|
// as well. We'll clear out the children to make sure it doesn't try to respill.
|
|
if n.parent != nil && n.parent.pgid == 0 {
|
|
n.children = nil
|
|
return n.parent.spill()
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// rebalance attempts to combine the node with sibling nodes if the node fill
|
|
// size is below a threshold or if there are not enough keys.
|
|
func (n *node) rebalance() {
|
|
if !n.unbalanced {
|
|
return
|
|
}
|
|
n.unbalanced = false
|
|
|
|
// Update statistics.
|
|
n.bucket.tx.stats.Rebalance++
|
|
|
|
// Ignore if node is above threshold (25%) and has enough keys.
|
|
var threshold = n.bucket.tx.db.pageSize / 4
|
|
if n.size() > threshold && len(n.inodes) > n.minKeys() {
|
|
return
|
|
}
|
|
|
|
// Root node has special handling.
|
|
if n.parent == nil {
|
|
// If root node is a branch and only has one node then collapse it.
|
|
if !n.isLeaf && len(n.inodes) == 1 {
|
|
// Move root's child up.
|
|
child := n.bucket.node(n.inodes[0].pgid, n)
|
|
n.isLeaf = child.isLeaf
|
|
n.inodes = child.inodes[:]
|
|
n.children = child.children
|
|
|
|
// Reparent all child nodes being moved.
|
|
for _, inode := range n.inodes {
|
|
if child, ok := n.bucket.nodes[inode.pgid]; ok {
|
|
child.parent = n
|
|
}
|
|
}
|
|
|
|
// Remove old child.
|
|
child.parent = nil
|
|
delete(n.bucket.nodes, child.pgid)
|
|
child.free()
|
|
}
|
|
|
|
return
|
|
}
|
|
|
|
// If node has no keys then just remove it.
|
|
if n.numChildren() == 0 {
|
|
n.parent.del(n.key)
|
|
n.parent.removeChild(n)
|
|
delete(n.bucket.nodes, n.pgid)
|
|
n.free()
|
|
n.parent.rebalance()
|
|
return
|
|
}
|
|
|
|
_assert(n.parent.numChildren() > 1, "parent must have at least 2 children")
|
|
|
|
// Destination node is right sibling if idx == 0, otherwise left sibling.
|
|
var target *node
|
|
var useNextSibling = (n.parent.childIndex(n) == 0)
|
|
if useNextSibling {
|
|
target = n.nextSibling()
|
|
} else {
|
|
target = n.prevSibling()
|
|
}
|
|
|
|
// If both this node and the target node are too small then merge them.
|
|
if useNextSibling {
|
|
// Reparent all child nodes being moved.
|
|
for _, inode := range target.inodes {
|
|
if child, ok := n.bucket.nodes[inode.pgid]; ok {
|
|
child.parent.removeChild(child)
|
|
child.parent = n
|
|
child.parent.children = append(child.parent.children, child)
|
|
}
|
|
}
|
|
|
|
// Copy over inodes from target and remove target.
|
|
n.inodes = append(n.inodes, target.inodes...)
|
|
n.parent.del(target.key)
|
|
n.parent.removeChild(target)
|
|
delete(n.bucket.nodes, target.pgid)
|
|
target.free()
|
|
} else {
|
|
// Reparent all child nodes being moved.
|
|
for _, inode := range n.inodes {
|
|
if child, ok := n.bucket.nodes[inode.pgid]; ok {
|
|
child.parent.removeChild(child)
|
|
child.parent = target
|
|
child.parent.children = append(child.parent.children, child)
|
|
}
|
|
}
|
|
|
|
// Copy over inodes to target and remove node.
|
|
target.inodes = append(target.inodes, n.inodes...)
|
|
n.parent.del(n.key)
|
|
n.parent.removeChild(n)
|
|
delete(n.bucket.nodes, n.pgid)
|
|
n.free()
|
|
}
|
|
|
|
// Either this node or the target node was deleted from the parent so rebalance it.
|
|
n.parent.rebalance()
|
|
}
|
|
|
|
// removes a node from the list of in-memory children.
|
|
// This does not affect the inodes.
|
|
func (n *node) removeChild(target *node) {
|
|
for i, child := range n.children {
|
|
if child == target {
|
|
n.children = append(n.children[:i], n.children[i+1:]...)
|
|
return
|
|
}
|
|
}
|
|
}
|
|
|
|
// dereference causes the node to copy all its inode key/value references to heap memory.
|
|
// This is required when the mmap is reallocated so inodes are not pointing to stale data.
|
|
func (n *node) dereference() {
|
|
if n.key != nil {
|
|
key := make([]byte, len(n.key))
|
|
copy(key, n.key)
|
|
n.key = key
|
|
_assert(n.pgid == 0 || len(n.key) > 0, "dereference: zero-length node key on existing node")
|
|
}
|
|
|
|
for i := range n.inodes {
|
|
inode := &n.inodes[i]
|
|
|
|
key := make([]byte, len(inode.key))
|
|
copy(key, inode.key)
|
|
inode.key = key
|
|
_assert(len(inode.key) > 0, "dereference: zero-length inode key")
|
|
|
|
value := make([]byte, len(inode.value))
|
|
copy(value, inode.value)
|
|
inode.value = value
|
|
}
|
|
|
|
// Recursively dereference children.
|
|
for _, child := range n.children {
|
|
child.dereference()
|
|
}
|
|
|
|
// Update statistics.
|
|
n.bucket.tx.stats.NodeDeref++
|
|
}
|
|
|
|
// free adds the node's underlying page to the freelist.
|
|
func (n *node) free() {
|
|
if n.pgid != 0 {
|
|
n.bucket.tx.db.freelist.free(n.bucket.tx.meta.txid, n.bucket.tx.page(n.pgid))
|
|
n.pgid = 0
|
|
}
|
|
}
|
|
|
|
// dump writes the contents of the node to STDERR for debugging purposes.
|
|
/*
|
|
func (n *node) dump() {
|
|
// Write node header.
|
|
var typ = "branch"
|
|
if n.isLeaf {
|
|
typ = "leaf"
|
|
}
|
|
warnf("[NODE %d {type=%s count=%d}]", n.pgid, typ, len(n.inodes))
|
|
|
|
// Write out abbreviated version of each item.
|
|
for _, item := range n.inodes {
|
|
if n.isLeaf {
|
|
if item.flags&bucketLeafFlag != 0 {
|
|
bucket := (*bucket)(unsafe.Pointer(&item.value[0]))
|
|
warnf("+L %08x -> (bucket root=%d)", trunc(item.key, 4), bucket.root)
|
|
} else {
|
|
warnf("+L %08x -> %08x", trunc(item.key, 4), trunc(item.value, 4))
|
|
}
|
|
} else {
|
|
warnf("+B %08x -> pgid=%d", trunc(item.key, 4), item.pgid)
|
|
}
|
|
}
|
|
warn("")
|
|
}
|
|
*/
|
|
|
|
type nodes []*node
|
|
|
|
func (s nodes) Len() int { return len(s) }
|
|
func (s nodes) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
|
|
func (s nodes) Less(i, j int) bool { return bytes.Compare(s[i].inodes[0].key, s[j].inodes[0].key) == -1 }
|
|
|
|
// inode represents an internal node inside of a node.
|
|
// It can be used to point to elements in a page or point
|
|
// to an element which hasn't been added to a page yet.
|
|
type inode struct {
|
|
flags uint32
|
|
pgid pgid
|
|
key []byte
|
|
value []byte
|
|
}
|
|
|
|
type inodes []inode
|