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path: root/vendor/github.com/etcd-io/bbolt/tx.go
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-rw-r--r--vendor/github.com/etcd-io/bbolt/tx.go726
1 files changed, 0 insertions, 726 deletions
diff --git a/vendor/github.com/etcd-io/bbolt/tx.go b/vendor/github.com/etcd-io/bbolt/tx.go
deleted file mode 100644
index 2df7688c2..000000000
--- a/vendor/github.com/etcd-io/bbolt/tx.go
+++ /dev/null
@@ -1,726 +0,0 @@
-package bbolt
-
-import (
- "fmt"
- "io"
- "os"
- "sort"
- "strings"
- "time"
- "unsafe"
-)
-
-// txid represents the internal transaction identifier.
-type txid uint64
-
-// Tx represents a read-only or read/write transaction on the database.
-// Read-only transactions can be used for retrieving values for keys and creating cursors.
-// Read/write transactions can create and remove buckets and create and remove keys.
-//
-// IMPORTANT: You must commit or rollback transactions when you are done with
-// them. Pages can not be reclaimed by the writer until no more transactions
-// are using them. A long running read transaction can cause the database to
-// quickly grow.
-type Tx struct {
- writable bool
- managed bool
- db *DB
- meta *meta
- root Bucket
- pages map[pgid]*page
- stats TxStats
- commitHandlers []func()
-
- // WriteFlag specifies the flag for write-related methods like WriteTo().
- // Tx opens the database file with the specified flag to copy the data.
- //
- // By default, the flag is unset, which works well for mostly in-memory
- // workloads. For databases that are much larger than available RAM,
- // set the flag to syscall.O_DIRECT to avoid trashing the page cache.
- WriteFlag int
-}
-
-// init initializes the transaction.
-func (tx *Tx) init(db *DB) {
- tx.db = db
- tx.pages = nil
-
- // Copy the meta page since it can be changed by the writer.
- tx.meta = &meta{}
- db.meta().copy(tx.meta)
-
- // Copy over the root bucket.
- tx.root = newBucket(tx)
- tx.root.bucket = &bucket{}
- *tx.root.bucket = tx.meta.root
-
- // Increment the transaction id and add a page cache for writable transactions.
- if tx.writable {
- tx.pages = make(map[pgid]*page)
- tx.meta.txid += txid(1)
- }
-}
-
-// ID returns the transaction id.
-func (tx *Tx) ID() int {
- return int(tx.meta.txid)
-}
-
-// DB returns a reference to the database that created the transaction.
-func (tx *Tx) DB() *DB {
- return tx.db
-}
-
-// Size returns current database size in bytes as seen by this transaction.
-func (tx *Tx) Size() int64 {
- return int64(tx.meta.pgid) * int64(tx.db.pageSize)
-}
-
-// Writable returns whether the transaction can perform write operations.
-func (tx *Tx) Writable() bool {
- return tx.writable
-}
-
-// Cursor creates a cursor associated with the root bucket.
-// All items in the cursor will return a nil value because all root bucket keys point to buckets.
-// The cursor is only valid as long as the transaction is open.
-// Do not use a cursor after the transaction is closed.
-func (tx *Tx) Cursor() *Cursor {
- return tx.root.Cursor()
-}
-
-// Stats retrieves a copy of the current transaction statistics.
-func (tx *Tx) Stats() TxStats {
- return tx.stats
-}
-
-// Bucket retrieves a bucket by name.
-// Returns nil if the bucket does not exist.
-// The bucket instance is only valid for the lifetime of the transaction.
-func (tx *Tx) Bucket(name []byte) *Bucket {
- return tx.root.Bucket(name)
-}
-
-// CreateBucket creates a new bucket.
-// Returns an error if the bucket already exists, if the bucket name is blank, or if the bucket name is too long.
-// The bucket instance is only valid for the lifetime of the transaction.
-func (tx *Tx) CreateBucket(name []byte) (*Bucket, error) {
- return tx.root.CreateBucket(name)
-}
-
-// CreateBucketIfNotExists creates a new bucket if it doesn't already exist.
-// Returns an error if the bucket name is blank, or if the bucket name is too long.
-// The bucket instance is only valid for the lifetime of the transaction.
-func (tx *Tx) CreateBucketIfNotExists(name []byte) (*Bucket, error) {
- return tx.root.CreateBucketIfNotExists(name)
-}
-
-// DeleteBucket deletes a bucket.
-// Returns an error if the bucket cannot be found or if the key represents a non-bucket value.
-func (tx *Tx) DeleteBucket(name []byte) error {
- return tx.root.DeleteBucket(name)
-}
-
-// ForEach executes a function for each bucket in the root.
-// If the provided function returns an error then the iteration is stopped and
-// the error is returned to the caller.
-func (tx *Tx) ForEach(fn func(name []byte, b *Bucket) error) error {
- return tx.root.ForEach(func(k, v []byte) error {
- return fn(k, tx.root.Bucket(k))
- })
-}
-
-// OnCommit adds a handler function to be executed after the transaction successfully commits.
-func (tx *Tx) OnCommit(fn func()) {
- tx.commitHandlers = append(tx.commitHandlers, fn)
-}
-
-// Commit writes all changes to disk and updates the meta page.
-// Returns an error if a disk write error occurs, or if Commit is
-// called on a read-only transaction.
-func (tx *Tx) Commit() error {
- _assert(!tx.managed, "managed tx commit not allowed")
- if tx.db == nil {
- return ErrTxClosed
- } else if !tx.writable {
- return ErrTxNotWritable
- }
-
- // TODO(benbjohnson): Use vectorized I/O to write out dirty pages.
-
- // Rebalance nodes which have had deletions.
- var startTime = time.Now()
- tx.root.rebalance()
- if tx.stats.Rebalance > 0 {
- tx.stats.RebalanceTime += time.Since(startTime)
- }
-
- // spill data onto dirty pages.
- startTime = time.Now()
- if err := tx.root.spill(); err != nil {
- tx.rollback()
- return err
- }
- tx.stats.SpillTime += time.Since(startTime)
-
- // Free the old root bucket.
- tx.meta.root.root = tx.root.root
-
- // Free the old freelist because commit writes out a fresh freelist.
- if tx.meta.freelist != pgidNoFreelist {
- tx.db.freelist.free(tx.meta.txid, tx.db.page(tx.meta.freelist))
- }
-
- if !tx.db.NoFreelistSync {
- err := tx.commitFreelist()
- if err != nil {
- return err
- }
- } else {
- tx.meta.freelist = pgidNoFreelist
- }
-
- // Write dirty pages to disk.
- startTime = time.Now()
- if err := tx.write(); err != nil {
- tx.rollback()
- return err
- }
-
- // If strict mode is enabled then perform a consistency check.
- // Only the first consistency error is reported in the panic.
- if tx.db.StrictMode {
- ch := tx.Check()
- var errs []string
- for {
- err, ok := <-ch
- if !ok {
- break
- }
- errs = append(errs, err.Error())
- }
- if len(errs) > 0 {
- panic("check fail: " + strings.Join(errs, "\n"))
- }
- }
-
- // Write meta to disk.
- if err := tx.writeMeta(); err != nil {
- tx.rollback()
- return err
- }
- tx.stats.WriteTime += time.Since(startTime)
-
- // Finalize the transaction.
- tx.close()
-
- // Execute commit handlers now that the locks have been removed.
- for _, fn := range tx.commitHandlers {
- fn()
- }
-
- return nil
-}
-
-func (tx *Tx) commitFreelist() error {
- // Allocate new pages for the new free list. This will overestimate
- // the size of the freelist but not underestimate the size (which would be bad).
- opgid := tx.meta.pgid
- p, err := tx.allocate((tx.db.freelist.size() / tx.db.pageSize) + 1)
- if err != nil {
- tx.rollback()
- return err
- }
- if err := tx.db.freelist.write(p); err != nil {
- tx.rollback()
- return err
- }
- tx.meta.freelist = p.id
- // If the high water mark has moved up then attempt to grow the database.
- if tx.meta.pgid > opgid {
- if err := tx.db.grow(int(tx.meta.pgid+1) * tx.db.pageSize); err != nil {
- tx.rollback()
- return err
- }
- }
-
- return nil
-}
-
-// Rollback closes the transaction and ignores all previous updates. Read-only
-// transactions must be rolled back and not committed.
-func (tx *Tx) Rollback() error {
- _assert(!tx.managed, "managed tx rollback not allowed")
- if tx.db == nil {
- return ErrTxClosed
- }
- tx.nonPhysicalRollback()
- return nil
-}
-
-// nonPhysicalRollback is called when user calls Rollback directly, in this case we do not need to reload the free pages from disk.
-func (tx *Tx) nonPhysicalRollback() {
- if tx.db == nil {
- return
- }
- if tx.writable {
- tx.db.freelist.rollback(tx.meta.txid)
- }
- tx.close()
-}
-
-// rollback needs to reload the free pages from disk in case some system error happens like fsync error.
-func (tx *Tx) rollback() {
- if tx.db == nil {
- return
- }
- if tx.writable {
- tx.db.freelist.rollback(tx.meta.txid)
- if !tx.db.hasSyncedFreelist() {
- // Reconstruct free page list by scanning the DB to get the whole free page list.
- // Note: scaning the whole db is heavy if your db size is large in NoSyncFreeList mode.
- tx.db.freelist.noSyncReload(tx.db.freepages())
- } else {
- // Read free page list from freelist page.
- tx.db.freelist.reload(tx.db.page(tx.db.meta().freelist))
- }
- }
- tx.close()
-}
-
-func (tx *Tx) close() {
- if tx.db == nil {
- return
- }
- if tx.writable {
- // Grab freelist stats.
- var freelistFreeN = tx.db.freelist.free_count()
- var freelistPendingN = tx.db.freelist.pending_count()
- var freelistAlloc = tx.db.freelist.size()
-
- // Remove transaction ref & writer lock.
- tx.db.rwtx = nil
- tx.db.rwlock.Unlock()
-
- // Merge statistics.
- tx.db.statlock.Lock()
- tx.db.stats.FreePageN = freelistFreeN
- tx.db.stats.PendingPageN = freelistPendingN
- tx.db.stats.FreeAlloc = (freelistFreeN + freelistPendingN) * tx.db.pageSize
- tx.db.stats.FreelistInuse = freelistAlloc
- tx.db.stats.TxStats.add(&tx.stats)
- tx.db.statlock.Unlock()
- } else {
- tx.db.removeTx(tx)
- }
-
- // Clear all references.
- tx.db = nil
- tx.meta = nil
- tx.root = Bucket{tx: tx}
- tx.pages = nil
-}
-
-// Copy writes the entire database to a writer.
-// This function exists for backwards compatibility.
-//
-// Deprecated; Use WriteTo() instead.
-func (tx *Tx) Copy(w io.Writer) error {
- _, err := tx.WriteTo(w)
- return err
-}
-
-// WriteTo writes the entire database to a writer.
-// If err == nil then exactly tx.Size() bytes will be written into the writer.
-func (tx *Tx) WriteTo(w io.Writer) (n int64, err error) {
- // Attempt to open reader with WriteFlag
- f, err := tx.db.openFile(tx.db.path, os.O_RDONLY|tx.WriteFlag, 0)
- if err != nil {
- return 0, err
- }
- defer func() {
- if cerr := f.Close(); err == nil {
- err = cerr
- }
- }()
-
- // Generate a meta page. We use the same page data for both meta pages.
- buf := make([]byte, tx.db.pageSize)
- page := (*page)(unsafe.Pointer(&buf[0]))
- page.flags = metaPageFlag
- *page.meta() = *tx.meta
-
- // Write meta 0.
- page.id = 0
- page.meta().checksum = page.meta().sum64()
- nn, err := w.Write(buf)
- n += int64(nn)
- if err != nil {
- return n, fmt.Errorf("meta 0 copy: %s", err)
- }
-
- // Write meta 1 with a lower transaction id.
- page.id = 1
- page.meta().txid -= 1
- page.meta().checksum = page.meta().sum64()
- nn, err = w.Write(buf)
- n += int64(nn)
- if err != nil {
- return n, fmt.Errorf("meta 1 copy: %s", err)
- }
-
- // Move past the meta pages in the file.
- if _, err := f.Seek(int64(tx.db.pageSize*2), io.SeekStart); err != nil {
- return n, fmt.Errorf("seek: %s", err)
- }
-
- // Copy data pages.
- wn, err := io.CopyN(w, f, tx.Size()-int64(tx.db.pageSize*2))
- n += wn
- if err != nil {
- return n, err
- }
-
- return n, nil
-}
-
-// CopyFile copies the entire database to file at the given path.
-// A reader transaction is maintained during the copy so it is safe to continue
-// using the database while a copy is in progress.
-func (tx *Tx) CopyFile(path string, mode os.FileMode) error {
- f, err := tx.db.openFile(path, os.O_RDWR|os.O_CREATE|os.O_TRUNC, mode)
- if err != nil {
- return err
- }
-
- err = tx.Copy(f)
- if err != nil {
- _ = f.Close()
- return err
- }
- return f.Close()
-}
-
-// Check performs several consistency checks on the database for this transaction.
-// An error is returned if any inconsistency is found.
-//
-// It can be safely run concurrently on a writable transaction. However, this
-// incurs a high cost for large databases and databases with a lot of subbuckets
-// because of caching. This overhead can be removed if running on a read-only
-// transaction, however, it is not safe to execute other writer transactions at
-// the same time.
-func (tx *Tx) Check() <-chan error {
- ch := make(chan error)
- go tx.check(ch)
- return ch
-}
-
-func (tx *Tx) check(ch chan error) {
- // Force loading free list if opened in ReadOnly mode.
- tx.db.loadFreelist()
-
- // Check if any pages are double freed.
- freed := make(map[pgid]bool)
- all := make([]pgid, tx.db.freelist.count())
- tx.db.freelist.copyall(all)
- for _, id := range all {
- if freed[id] {
- ch <- fmt.Errorf("page %d: already freed", id)
- }
- freed[id] = true
- }
-
- // Track every reachable page.
- reachable := make(map[pgid]*page)
- reachable[0] = tx.page(0) // meta0
- reachable[1] = tx.page(1) // meta1
- if tx.meta.freelist != pgidNoFreelist {
- for i := uint32(0); i <= tx.page(tx.meta.freelist).overflow; i++ {
- reachable[tx.meta.freelist+pgid(i)] = tx.page(tx.meta.freelist)
- }
- }
-
- // Recursively check buckets.
- tx.checkBucket(&tx.root, reachable, freed, ch)
-
- // Ensure all pages below high water mark are either reachable or freed.
- for i := pgid(0); i < tx.meta.pgid; i++ {
- _, isReachable := reachable[i]
- if !isReachable && !freed[i] {
- ch <- fmt.Errorf("page %d: unreachable unfreed", int(i))
- }
- }
-
- // Close the channel to signal completion.
- close(ch)
-}
-
-func (tx *Tx) checkBucket(b *Bucket, reachable map[pgid]*page, freed map[pgid]bool, ch chan error) {
- // Ignore inline buckets.
- if b.root == 0 {
- return
- }
-
- // Check every page used by this bucket.
- b.tx.forEachPage(b.root, 0, func(p *page, _ int) {
- if p.id > tx.meta.pgid {
- ch <- fmt.Errorf("page %d: out of bounds: %d", int(p.id), int(b.tx.meta.pgid))
- }
-
- // Ensure each page is only referenced once.
- for i := pgid(0); i <= pgid(p.overflow); i++ {
- var id = p.id + i
- if _, ok := reachable[id]; ok {
- ch <- fmt.Errorf("page %d: multiple references", int(id))
- }
- reachable[id] = p
- }
-
- // We should only encounter un-freed leaf and branch pages.
- if freed[p.id] {
- ch <- fmt.Errorf("page %d: reachable freed", int(p.id))
- } else if (p.flags&branchPageFlag) == 0 && (p.flags&leafPageFlag) == 0 {
- ch <- fmt.Errorf("page %d: invalid type: %s", int(p.id), p.typ())
- }
- })
-
- // Check each bucket within this bucket.
- _ = b.ForEach(func(k, v []byte) error {
- if child := b.Bucket(k); child != nil {
- tx.checkBucket(child, reachable, freed, ch)
- }
- return nil
- })
-}
-
-// allocate returns a contiguous block of memory starting at a given page.
-func (tx *Tx) allocate(count int) (*page, error) {
- p, err := tx.db.allocate(tx.meta.txid, count)
- if err != nil {
- return nil, err
- }
-
- // Save to our page cache.
- tx.pages[p.id] = p
-
- // Update statistics.
- tx.stats.PageCount += count
- tx.stats.PageAlloc += count * tx.db.pageSize
-
- return p, nil
-}
-
-// write writes any dirty pages to disk.
-func (tx *Tx) write() error {
- // Sort pages by id.
- pages := make(pages, 0, len(tx.pages))
- for _, p := range tx.pages {
- pages = append(pages, p)
- }
- // Clear out page cache early.
- tx.pages = make(map[pgid]*page)
- sort.Sort(pages)
-
- // Write pages to disk in order.
- for _, p := range pages {
- size := (int(p.overflow) + 1) * tx.db.pageSize
- offset := int64(p.id) * int64(tx.db.pageSize)
-
- // Write out page in "max allocation" sized chunks.
- ptr := (*[maxAllocSize]byte)(unsafe.Pointer(p))
- for {
- // Limit our write to our max allocation size.
- sz := size
- if sz > maxAllocSize-1 {
- sz = maxAllocSize - 1
- }
-
- // Write chunk to disk.
- buf := ptr[:sz]
- if _, err := tx.db.ops.writeAt(buf, offset); err != nil {
- return err
- }
-
- // Update statistics.
- tx.stats.Write++
-
- // Exit inner for loop if we've written all the chunks.
- size -= sz
- if size == 0 {
- break
- }
-
- // Otherwise move offset forward and move pointer to next chunk.
- offset += int64(sz)
- ptr = (*[maxAllocSize]byte)(unsafe.Pointer(&ptr[sz]))
- }
- }
-
- // Ignore file sync if flag is set on DB.
- if !tx.db.NoSync || IgnoreNoSync {
- if err := fdatasync(tx.db); err != nil {
- return err
- }
- }
-
- // Put small pages back to page pool.
- for _, p := range pages {
- // Ignore page sizes over 1 page.
- // These are allocated using make() instead of the page pool.
- if int(p.overflow) != 0 {
- continue
- }
-
- buf := (*[maxAllocSize]byte)(unsafe.Pointer(p))[:tx.db.pageSize]
-
- // See https://go.googlesource.com/go/+/f03c9202c43e0abb130669852082117ca50aa9b1
- for i := range buf {
- buf[i] = 0
- }
- tx.db.pagePool.Put(buf)
- }
-
- return nil
-}
-
-// writeMeta writes the meta to the disk.
-func (tx *Tx) writeMeta() error {
- // Create a temporary buffer for the meta page.
- buf := make([]byte, tx.db.pageSize)
- p := tx.db.pageInBuffer(buf, 0)
- tx.meta.write(p)
-
- // Write the meta page to file.
- if _, err := tx.db.ops.writeAt(buf, int64(p.id)*int64(tx.db.pageSize)); err != nil {
- return err
- }
- if !tx.db.NoSync || IgnoreNoSync {
- if err := fdatasync(tx.db); err != nil {
- return err
- }
- }
-
- // Update statistics.
- tx.stats.Write++
-
- return nil
-}
-
-// page returns a reference to the page with a given id.
-// If page has been written to then a temporary buffered page is returned.
-func (tx *Tx) page(id pgid) *page {
- // Check the dirty pages first.
- if tx.pages != nil {
- if p, ok := tx.pages[id]; ok {
- return p
- }
- }
-
- // Otherwise return directly from the mmap.
- return tx.db.page(id)
-}
-
-// forEachPage iterates over every page within a given page and executes a function.
-func (tx *Tx) forEachPage(pgid pgid, depth int, fn func(*page, int)) {
- p := tx.page(pgid)
-
- // Execute function.
- fn(p, depth)
-
- // Recursively loop over children.
- if (p.flags & branchPageFlag) != 0 {
- for i := 0; i < int(p.count); i++ {
- elem := p.branchPageElement(uint16(i))
- tx.forEachPage(elem.pgid, depth+1, fn)
- }
- }
-}
-
-// Page returns page information for a given page number.
-// This is only safe for concurrent use when used by a writable transaction.
-func (tx *Tx) Page(id int) (*PageInfo, error) {
- if tx.db == nil {
- return nil, ErrTxClosed
- } else if pgid(id) >= tx.meta.pgid {
- return nil, nil
- }
-
- // Build the page info.
- p := tx.db.page(pgid(id))
- info := &PageInfo{
- ID: id,
- Count: int(p.count),
- OverflowCount: int(p.overflow),
- }
-
- // Determine the type (or if it's free).
- if tx.db.freelist.freed(pgid(id)) {
- info.Type = "free"
- } else {
- info.Type = p.typ()
- }
-
- return info, nil
-}
-
-// TxStats represents statistics about the actions performed by the transaction.
-type TxStats struct {
- // Page statistics.
- PageCount int // number of page allocations
- PageAlloc int // total bytes allocated
-
- // Cursor statistics.
- CursorCount int // number of cursors created
-
- // Node statistics
- NodeCount int // number of node allocations
- NodeDeref int // number of node dereferences
-
- // Rebalance statistics.
- Rebalance int // number of node rebalances
- RebalanceTime time.Duration // total time spent rebalancing
-
- // Split/Spill statistics.
- Split int // number of nodes split
- Spill int // number of nodes spilled
- SpillTime time.Duration // total time spent spilling
-
- // Write statistics.
- Write int // number of writes performed
- WriteTime time.Duration // total time spent writing to disk
-}
-
-func (s *TxStats) add(other *TxStats) {
- s.PageCount += other.PageCount
- s.PageAlloc += other.PageAlloc
- s.CursorCount += other.CursorCount
- s.NodeCount += other.NodeCount
- s.NodeDeref += other.NodeDeref
- s.Rebalance += other.Rebalance
- s.RebalanceTime += other.RebalanceTime
- s.Split += other.Split
- s.Spill += other.Spill
- s.SpillTime += other.SpillTime
- s.Write += other.Write
- s.WriteTime += other.WriteTime
-}
-
-// Sub calculates and returns the difference between two sets of transaction stats.
-// This is useful when obtaining stats at two different points and time and
-// you need the performance counters that occurred within that time span.
-func (s *TxStats) Sub(other *TxStats) TxStats {
- var diff TxStats
- diff.PageCount = s.PageCount - other.PageCount
- diff.PageAlloc = s.PageAlloc - other.PageAlloc
- diff.CursorCount = s.CursorCount - other.CursorCount
- diff.NodeCount = s.NodeCount - other.NodeCount
- diff.NodeDeref = s.NodeDeref - other.NodeDeref
- diff.Rebalance = s.Rebalance - other.Rebalance
- diff.RebalanceTime = s.RebalanceTime - other.RebalanceTime
- diff.Split = s.Split - other.Split
- diff.Spill = s.Spill - other.Spill
- diff.SpillTime = s.SpillTime - other.SpillTime
- diff.Write = s.Write - other.Write
- diff.WriteTime = s.WriteTime - other.WriteTime
- return diff
-}