From 366001fb5fa96b3b0f2f9e84b7ebc56dc4c94adc Mon Sep 17 00:00:00 2001 From: Daniel J Walsh Date: Sun, 29 Mar 2020 06:16:27 -0400 Subject: Update vendor of boltdb and containers/image Signed-off-by: Daniel J Walsh --- vendor/github.com/etcd-io/bbolt/db.go | 1174 --------------------------------- 1 file changed, 1174 deletions(-) delete mode 100644 vendor/github.com/etcd-io/bbolt/db.go (limited to 'vendor/github.com/etcd-io/bbolt/db.go') diff --git a/vendor/github.com/etcd-io/bbolt/db.go b/vendor/github.com/etcd-io/bbolt/db.go deleted file mode 100644 index 870c8b1cc..000000000 --- a/vendor/github.com/etcd-io/bbolt/db.go +++ /dev/null @@ -1,1174 +0,0 @@ -package bbolt - -import ( - "errors" - "fmt" - "hash/fnv" - "log" - "os" - "runtime" - "sort" - "sync" - "time" - "unsafe" -) - -// The largest step that can be taken when remapping the mmap. -const maxMmapStep = 1 << 30 // 1GB - -// The data file format version. -const version = 2 - -// Represents a marker value to indicate that a file is a Bolt DB. -const magic uint32 = 0xED0CDAED - -const pgidNoFreelist pgid = 0xffffffffffffffff - -// IgnoreNoSync specifies whether the NoSync field of a DB is ignored when -// syncing changes to a file. This is required as some operating systems, -// such as OpenBSD, do not have a unified buffer cache (UBC) and writes -// must be synchronized using the msync(2) syscall. -const IgnoreNoSync = runtime.GOOS == "openbsd" - -// Default values if not set in a DB instance. -const ( - DefaultMaxBatchSize int = 1000 - DefaultMaxBatchDelay = 10 * time.Millisecond - DefaultAllocSize = 16 * 1024 * 1024 -) - -// default page size for db is set to the OS page size. -var defaultPageSize = os.Getpagesize() - -// The time elapsed between consecutive file locking attempts. -const flockRetryTimeout = 50 * time.Millisecond - -// FreelistType is the type of the freelist backend -type FreelistType string - -const ( - // FreelistArrayType indicates backend freelist type is array - FreelistArrayType = FreelistType("array") - // FreelistMapType indicates backend freelist type is hashmap - FreelistMapType = FreelistType("hashmap") -) - -// DB represents a collection of buckets persisted to a file on disk. -// All data access is performed through transactions which can be obtained through the DB. -// All the functions on DB will return a ErrDatabaseNotOpen if accessed before Open() is called. -type DB struct { - // When enabled, the database will perform a Check() after every commit. - // A panic is issued if the database is in an inconsistent state. This - // flag has a large performance impact so it should only be used for - // debugging purposes. - StrictMode bool - - // Setting the NoSync flag will cause the database to skip fsync() - // calls after each commit. This can be useful when bulk loading data - // into a database and you can restart the bulk load in the event of - // a system failure or database corruption. Do not set this flag for - // normal use. - // - // If the package global IgnoreNoSync constant is true, this value is - // ignored. See the comment on that constant for more details. - // - // THIS IS UNSAFE. PLEASE USE WITH CAUTION. - NoSync bool - - // When true, skips syncing freelist to disk. This improves the database - // write performance under normal operation, but requires a full database - // re-sync during recovery. - NoFreelistSync bool - - // FreelistType sets the backend freelist type. There are two options. Array which is simple but endures - // dramatic performance degradation if database is large and framentation in freelist is common. - // The alternative one is using hashmap, it is faster in almost all circumstances - // but it doesn't guarantee that it offers the smallest page id available. In normal case it is safe. - // The default type is array - FreelistType FreelistType - - // When true, skips the truncate call when growing the database. - // Setting this to true is only safe on non-ext3/ext4 systems. - // Skipping truncation avoids preallocation of hard drive space and - // bypasses a truncate() and fsync() syscall on remapping. - // - // https://github.com/boltdb/bolt/issues/284 - NoGrowSync bool - - // If you want to read the entire database fast, you can set MmapFlag to - // syscall.MAP_POPULATE on Linux 2.6.23+ for sequential read-ahead. - MmapFlags int - - // MaxBatchSize is the maximum size of a batch. Default value is - // copied from DefaultMaxBatchSize in Open. - // - // If <=0, disables batching. - // - // Do not change concurrently with calls to Batch. - MaxBatchSize int - - // MaxBatchDelay is the maximum delay before a batch starts. - // Default value is copied from DefaultMaxBatchDelay in Open. - // - // If <=0, effectively disables batching. - // - // Do not change concurrently with calls to Batch. - MaxBatchDelay time.Duration - - // AllocSize is the amount of space allocated when the database - // needs to create new pages. This is done to amortize the cost - // of truncate() and fsync() when growing the data file. - AllocSize int - - path string - openFile func(string, int, os.FileMode) (*os.File, error) - file *os.File - dataref []byte // mmap'ed readonly, write throws SEGV - data *[maxMapSize]byte - datasz int - filesz int // current on disk file size - meta0 *meta - meta1 *meta - pageSize int - opened bool - rwtx *Tx - txs []*Tx - stats Stats - - freelist *freelist - freelistLoad sync.Once - - pagePool sync.Pool - - batchMu sync.Mutex - batch *batch - - rwlock sync.Mutex // Allows only one writer at a time. - metalock sync.Mutex // Protects meta page access. - mmaplock sync.RWMutex // Protects mmap access during remapping. - statlock sync.RWMutex // Protects stats access. - - ops struct { - writeAt func(b []byte, off int64) (n int, err error) - } - - // Read only mode. - // When true, Update() and Begin(true) return ErrDatabaseReadOnly immediately. - readOnly bool -} - -// Path returns the path to currently open database file. -func (db *DB) Path() string { - return db.path -} - -// GoString returns the Go string representation of the database. -func (db *DB) GoString() string { - return fmt.Sprintf("bolt.DB{path:%q}", db.path) -} - -// String returns the string representation of the database. -func (db *DB) String() string { - return fmt.Sprintf("DB<%q>", db.path) -} - -// Open creates and opens a database at the given path. -// If the file does not exist then it will be created automatically. -// Passing in nil options will cause Bolt to open the database with the default options. -func Open(path string, mode os.FileMode, options *Options) (*DB, error) { - db := &DB{ - opened: true, - } - // Set default options if no options are provided. - if options == nil { - options = DefaultOptions - } - db.NoSync = options.NoSync - db.NoGrowSync = options.NoGrowSync - db.MmapFlags = options.MmapFlags - db.NoFreelistSync = options.NoFreelistSync - db.FreelistType = options.FreelistType - - // Set default values for later DB operations. - db.MaxBatchSize = DefaultMaxBatchSize - db.MaxBatchDelay = DefaultMaxBatchDelay - db.AllocSize = DefaultAllocSize - - flag := os.O_RDWR - if options.ReadOnly { - flag = os.O_RDONLY - db.readOnly = true - } - - db.openFile = options.OpenFile - if db.openFile == nil { - db.openFile = os.OpenFile - } - - // Open data file and separate sync handler for metadata writes. - db.path = path - var err error - if db.file, err = db.openFile(db.path, flag|os.O_CREATE, mode); err != nil { - _ = db.close() - return nil, err - } - - // Lock file so that other processes using Bolt in read-write mode cannot - // use the database at the same time. This would cause corruption since - // the two processes would write meta pages and free pages separately. - // The database file is locked exclusively (only one process can grab the lock) - // if !options.ReadOnly. - // The database file is locked using the shared lock (more than one process may - // hold a lock at the same time) otherwise (options.ReadOnly is set). - if err := flock(db, !db.readOnly, options.Timeout); err != nil { - _ = db.close() - return nil, err - } - - // Default values for test hooks - db.ops.writeAt = db.file.WriteAt - - if db.pageSize = options.PageSize; db.pageSize == 0 { - // Set the default page size to the OS page size. - db.pageSize = defaultPageSize - } - - // Initialize the database if it doesn't exist. - if info, err := db.file.Stat(); err != nil { - _ = db.close() - return nil, err - } else if info.Size() == 0 { - // Initialize new files with meta pages. - if err := db.init(); err != nil { - // clean up file descriptor on initialization fail - _ = db.close() - return nil, err - } - } else { - // Read the first meta page to determine the page size. - var buf [0x1000]byte - // If we can't read the page size, but can read a page, assume - // it's the same as the OS or one given -- since that's how the - // page size was chosen in the first place. - // - // If the first page is invalid and this OS uses a different - // page size than what the database was created with then we - // are out of luck and cannot access the database. - // - // TODO: scan for next page - if bw, err := db.file.ReadAt(buf[:], 0); err == nil && bw == len(buf) { - if m := db.pageInBuffer(buf[:], 0).meta(); m.validate() == nil { - db.pageSize = int(m.pageSize) - } - } else { - _ = db.close() - return nil, ErrInvalid - } - } - - // Initialize page pool. - db.pagePool = sync.Pool{ - New: func() interface{} { - return make([]byte, db.pageSize) - }, - } - - // Memory map the data file. - if err := db.mmap(options.InitialMmapSize); err != nil { - _ = db.close() - return nil, err - } - - if db.readOnly { - return db, nil - } - - db.loadFreelist() - - // Flush freelist when transitioning from no sync to sync so - // NoFreelistSync unaware boltdb can open the db later. - if !db.NoFreelistSync && !db.hasSyncedFreelist() { - tx, err := db.Begin(true) - if tx != nil { - err = tx.Commit() - } - if err != nil { - _ = db.close() - return nil, err - } - } - - // Mark the database as opened and return. - return db, nil -} - -// loadFreelist reads the freelist if it is synced, or reconstructs it -// by scanning the DB if it is not synced. It assumes there are no -// concurrent accesses being made to the freelist. -func (db *DB) loadFreelist() { - db.freelistLoad.Do(func() { - db.freelist = newFreelist(db.FreelistType) - if !db.hasSyncedFreelist() { - // Reconstruct free list by scanning the DB. - db.freelist.readIDs(db.freepages()) - } else { - // Read free list from freelist page. - db.freelist.read(db.page(db.meta().freelist)) - } - db.stats.FreePageN = db.freelist.free_count() - }) -} - -func (db *DB) hasSyncedFreelist() bool { - return db.meta().freelist != pgidNoFreelist -} - -// mmap opens the underlying memory-mapped file and initializes the meta references. -// minsz is the minimum size that the new mmap can be. -func (db *DB) mmap(minsz int) error { - db.mmaplock.Lock() - defer db.mmaplock.Unlock() - - info, err := db.file.Stat() - if err != nil { - return fmt.Errorf("mmap stat error: %s", err) - } else if int(info.Size()) < db.pageSize*2 { - return fmt.Errorf("file size too small") - } - - // Ensure the size is at least the minimum size. - var size = int(info.Size()) - if size < minsz { - size = minsz - } - size, err = db.mmapSize(size) - if err != nil { - return err - } - - // Dereference all mmap references before unmapping. - if db.rwtx != nil { - db.rwtx.root.dereference() - } - - // Unmap existing data before continuing. - if err := db.munmap(); err != nil { - return err - } - - // Memory-map the data file as a byte slice. - if err := mmap(db, size); err != nil { - return err - } - - // Save references to the meta pages. - db.meta0 = db.page(0).meta() - db.meta1 = db.page(1).meta() - - // Validate the meta pages. We only return an error if both meta pages fail - // validation, since meta0 failing validation means that it wasn't saved - // properly -- but we can recover using meta1. And vice-versa. - err0 := db.meta0.validate() - err1 := db.meta1.validate() - if err0 != nil && err1 != nil { - return err0 - } - - return nil -} - -// munmap unmaps the data file from memory. -func (db *DB) munmap() error { - if err := munmap(db); err != nil { - return fmt.Errorf("unmap error: " + err.Error()) - } - return nil -} - -// mmapSize determines the appropriate size for the mmap given the current size -// of the database. The minimum size is 32KB and doubles until it reaches 1GB. -// Returns an error if the new mmap size is greater than the max allowed. -func (db *DB) mmapSize(size int) (int, error) { - // Double the size from 32KB until 1GB. - for i := uint(15); i <= 30; i++ { - if size <= 1< maxMapSize { - return 0, fmt.Errorf("mmap too large") - } - - // If larger than 1GB then grow by 1GB at a time. - sz := int64(size) - if remainder := sz % int64(maxMmapStep); remainder > 0 { - sz += int64(maxMmapStep) - remainder - } - - // Ensure that the mmap size is a multiple of the page size. - // This should always be true since we're incrementing in MBs. - pageSize := int64(db.pageSize) - if (sz % pageSize) != 0 { - sz = ((sz / pageSize) + 1) * pageSize - } - - // If we've exceeded the max size then only grow up to the max size. - if sz > maxMapSize { - sz = maxMapSize - } - - return int(sz), nil -} - -// init creates a new database file and initializes its meta pages. -func (db *DB) init() error { - // Create two meta pages on a buffer. - buf := make([]byte, db.pageSize*4) - for i := 0; i < 2; i++ { - p := db.pageInBuffer(buf[:], pgid(i)) - p.id = pgid(i) - p.flags = metaPageFlag - - // Initialize the meta page. - m := p.meta() - m.magic = magic - m.version = version - m.pageSize = uint32(db.pageSize) - m.freelist = 2 - m.root = bucket{root: 3} - m.pgid = 4 - m.txid = txid(i) - m.checksum = m.sum64() - } - - // Write an empty freelist at page 3. - p := db.pageInBuffer(buf[:], pgid(2)) - p.id = pgid(2) - p.flags = freelistPageFlag - p.count = 0 - - // Write an empty leaf page at page 4. - p = db.pageInBuffer(buf[:], pgid(3)) - p.id = pgid(3) - p.flags = leafPageFlag - p.count = 0 - - // Write the buffer to our data file. - if _, err := db.ops.writeAt(buf, 0); err != nil { - return err - } - if err := fdatasync(db); err != nil { - return err - } - - return nil -} - -// Close releases all database resources. -// It will block waiting for any open transactions to finish -// before closing the database and returning. -func (db *DB) Close() error { - db.rwlock.Lock() - defer db.rwlock.Unlock() - - db.metalock.Lock() - defer db.metalock.Unlock() - - db.mmaplock.Lock() - defer db.mmaplock.Unlock() - - return db.close() -} - -func (db *DB) close() error { - if !db.opened { - return nil - } - - db.opened = false - - db.freelist = nil - - // Clear ops. - db.ops.writeAt = nil - - // Close the mmap. - if err := db.munmap(); err != nil { - return err - } - - // Close file handles. - if db.file != nil { - // No need to unlock read-only file. - if !db.readOnly { - // Unlock the file. - if err := funlock(db); err != nil { - log.Printf("bolt.Close(): funlock error: %s", err) - } - } - - // Close the file descriptor. - if err := db.file.Close(); err != nil { - return fmt.Errorf("db file close: %s", err) - } - db.file = nil - } - - db.path = "" - return nil -} - -// Begin starts a new transaction. -// Multiple read-only transactions can be used concurrently but only one -// write transaction can be used at a time. Starting multiple write transactions -// will cause the calls to block and be serialized until the current write -// transaction finishes. -// -// Transactions should not be dependent on one another. Opening a read -// transaction and a write transaction in the same goroutine can cause the -// writer to deadlock because the database periodically needs to re-mmap itself -// as it grows and it cannot do that while a read transaction is open. -// -// If a long running read transaction (for example, a snapshot transaction) is -// needed, you might want to set DB.InitialMmapSize to a large enough value -// to avoid potential blocking of write transaction. -// -// IMPORTANT: You must close read-only transactions after you are finished or -// else the database will not reclaim old pages. -func (db *DB) Begin(writable bool) (*Tx, error) { - if writable { - return db.beginRWTx() - } - return db.beginTx() -} - -func (db *DB) beginTx() (*Tx, error) { - // Lock the meta pages while we initialize the transaction. We obtain - // the meta lock before the mmap lock because that's the order that the - // write transaction will obtain them. - db.metalock.Lock() - - // Obtain a read-only lock on the mmap. When the mmap is remapped it will - // obtain a write lock so all transactions must finish before it can be - // remapped. - db.mmaplock.RLock() - - // Exit if the database is not open yet. - if !db.opened { - db.mmaplock.RUnlock() - db.metalock.Unlock() - return nil, ErrDatabaseNotOpen - } - - // Create a transaction associated with the database. - t := &Tx{} - t.init(db) - - // Keep track of transaction until it closes. - db.txs = append(db.txs, t) - n := len(db.txs) - - // Unlock the meta pages. - db.metalock.Unlock() - - // Update the transaction stats. - db.statlock.Lock() - db.stats.TxN++ - db.stats.OpenTxN = n - db.statlock.Unlock() - - return t, nil -} - -func (db *DB) beginRWTx() (*Tx, error) { - // If the database was opened with Options.ReadOnly, return an error. - if db.readOnly { - return nil, ErrDatabaseReadOnly - } - - // Obtain writer lock. This is released by the transaction when it closes. - // This enforces only one writer transaction at a time. - db.rwlock.Lock() - - // Once we have the writer lock then we can lock the meta pages so that - // we can set up the transaction. - db.metalock.Lock() - defer db.metalock.Unlock() - - // Exit if the database is not open yet. - if !db.opened { - db.rwlock.Unlock() - return nil, ErrDatabaseNotOpen - } - - // Create a transaction associated with the database. - t := &Tx{writable: true} - t.init(db) - db.rwtx = t - db.freePages() - return t, nil -} - -// freePages releases any pages associated with closed read-only transactions. -func (db *DB) freePages() { - // Free all pending pages prior to earliest open transaction. - sort.Sort(txsById(db.txs)) - minid := txid(0xFFFFFFFFFFFFFFFF) - if len(db.txs) > 0 { - minid = db.txs[0].meta.txid - } - if minid > 0 { - db.freelist.release(minid - 1) - } - // Release unused txid extents. - for _, t := range db.txs { - db.freelist.releaseRange(minid, t.meta.txid-1) - minid = t.meta.txid + 1 - } - db.freelist.releaseRange(minid, txid(0xFFFFFFFFFFFFFFFF)) - // Any page both allocated and freed in an extent is safe to release. -} - -type txsById []*Tx - -func (t txsById) Len() int { return len(t) } -func (t txsById) Swap(i, j int) { t[i], t[j] = t[j], t[i] } -func (t txsById) Less(i, j int) bool { return t[i].meta.txid < t[j].meta.txid } - -// removeTx removes a transaction from the database. -func (db *DB) removeTx(tx *Tx) { - // Release the read lock on the mmap. - db.mmaplock.RUnlock() - - // Use the meta lock to restrict access to the DB object. - db.metalock.Lock() - - // Remove the transaction. - for i, t := range db.txs { - if t == tx { - last := len(db.txs) - 1 - db.txs[i] = db.txs[last] - db.txs[last] = nil - db.txs = db.txs[:last] - break - } - } - n := len(db.txs) - - // Unlock the meta pages. - db.metalock.Unlock() - - // Merge statistics. - db.statlock.Lock() - db.stats.OpenTxN = n - db.stats.TxStats.add(&tx.stats) - db.statlock.Unlock() -} - -// Update executes a function within the context of a read-write managed transaction. -// If no error is returned from the function then the transaction is committed. -// If an error is returned then the entire transaction is rolled back. -// Any error that is returned from the function or returned from the commit is -// returned from the Update() method. -// -// Attempting to manually commit or rollback within the function will cause a panic. -func (db *DB) Update(fn func(*Tx) error) error { - t, err := db.Begin(true) - if err != nil { - return err - } - - // Make sure the transaction rolls back in the event of a panic. - defer func() { - if t.db != nil { - t.rollback() - } - }() - - // Mark as a managed tx so that the inner function cannot manually commit. - t.managed = true - - // If an error is returned from the function then rollback and return error. - err = fn(t) - t.managed = false - if err != nil { - _ = t.Rollback() - return err - } - - return t.Commit() -} - -// View executes a function within the context of a managed read-only transaction. -// Any error that is returned from the function is returned from the View() method. -// -// Attempting to manually rollback within the function will cause a panic. -func (db *DB) View(fn func(*Tx) error) error { - t, err := db.Begin(false) - if err != nil { - return err - } - - // Make sure the transaction rolls back in the event of a panic. - defer func() { - if t.db != nil { - t.rollback() - } - }() - - // Mark as a managed tx so that the inner function cannot manually rollback. - t.managed = true - - // If an error is returned from the function then pass it through. - err = fn(t) - t.managed = false - if err != nil { - _ = t.Rollback() - return err - } - - return t.Rollback() -} - -// Batch calls fn as part of a batch. It behaves similar to Update, -// except: -// -// 1. concurrent Batch calls can be combined into a single Bolt -// transaction. -// -// 2. the function passed to Batch may be called multiple times, -// regardless of whether it returns error or not. -// -// This means that Batch function side effects must be idempotent and -// take permanent effect only after a successful return is seen in -// caller. -// -// The maximum batch size and delay can be adjusted with DB.MaxBatchSize -// and DB.MaxBatchDelay, respectively. -// -// Batch is only useful when there are multiple goroutines calling it. -func (db *DB) Batch(fn func(*Tx) error) error { - errCh := make(chan error, 1) - - db.batchMu.Lock() - if (db.batch == nil) || (db.batch != nil && len(db.batch.calls) >= db.MaxBatchSize) { - // There is no existing batch, or the existing batch is full; start a new one. - db.batch = &batch{ - db: db, - } - db.batch.timer = time.AfterFunc(db.MaxBatchDelay, db.batch.trigger) - } - db.batch.calls = append(db.batch.calls, call{fn: fn, err: errCh}) - if len(db.batch.calls) >= db.MaxBatchSize { - // wake up batch, it's ready to run - go db.batch.trigger() - } - db.batchMu.Unlock() - - err := <-errCh - if err == trySolo { - err = db.Update(fn) - } - return err -} - -type call struct { - fn func(*Tx) error - err chan<- error -} - -type batch struct { - db *DB - timer *time.Timer - start sync.Once - calls []call -} - -// trigger runs the batch if it hasn't already been run. -func (b *batch) trigger() { - b.start.Do(b.run) -} - -// run performs the transactions in the batch and communicates results -// back to DB.Batch. -func (b *batch) run() { - b.db.batchMu.Lock() - b.timer.Stop() - // Make sure no new work is added to this batch, but don't break - // other batches. - if b.db.batch == b { - b.db.batch = nil - } - b.db.batchMu.Unlock() - -retry: - for len(b.calls) > 0 { - var failIdx = -1 - err := b.db.Update(func(tx *Tx) error { - for i, c := range b.calls { - if err := safelyCall(c.fn, tx); err != nil { - failIdx = i - return err - } - } - return nil - }) - - if failIdx >= 0 { - // take the failing transaction out of the batch. it's - // safe to shorten b.calls here because db.batch no longer - // points to us, and we hold the mutex anyway. - c := b.calls[failIdx] - b.calls[failIdx], b.calls = b.calls[len(b.calls)-1], b.calls[:len(b.calls)-1] - // tell the submitter re-run it solo, continue with the rest of the batch - c.err <- trySolo - continue retry - } - - // pass success, or bolt internal errors, to all callers - for _, c := range b.calls { - c.err <- err - } - break retry - } -} - -// trySolo is a special sentinel error value used for signaling that a -// transaction function should be re-run. It should never be seen by -// callers. -var trySolo = errors.New("batch function returned an error and should be re-run solo") - -type panicked struct { - reason interface{} -} - -func (p panicked) Error() string { - if err, ok := p.reason.(error); ok { - return err.Error() - } - return fmt.Sprintf("panic: %v", p.reason) -} - -func safelyCall(fn func(*Tx) error, tx *Tx) (err error) { - defer func() { - if p := recover(); p != nil { - err = panicked{p} - } - }() - return fn(tx) -} - -// Sync executes fdatasync() against the database file handle. -// -// This is not necessary under normal operation, however, if you use NoSync -// then it allows you to force the database file to sync against the disk. -func (db *DB) Sync() error { return fdatasync(db) } - -// Stats retrieves ongoing performance stats for the database. -// This is only updated when a transaction closes. -func (db *DB) Stats() Stats { - db.statlock.RLock() - defer db.statlock.RUnlock() - return db.stats -} - -// This is for internal access to the raw data bytes from the C cursor, use -// carefully, or not at all. -func (db *DB) Info() *Info { - return &Info{uintptr(unsafe.Pointer(&db.data[0])), db.pageSize} -} - -// page retrieves a page reference from the mmap based on the current page size. -func (db *DB) page(id pgid) *page { - pos := id * pgid(db.pageSize) - return (*page)(unsafe.Pointer(&db.data[pos])) -} - -// pageInBuffer retrieves a page reference from a given byte array based on the current page size. -func (db *DB) pageInBuffer(b []byte, id pgid) *page { - return (*page)(unsafe.Pointer(&b[id*pgid(db.pageSize)])) -} - -// meta retrieves the current meta page reference. -func (db *DB) meta() *meta { - // We have to return the meta with the highest txid which doesn't fail - // validation. Otherwise, we can cause errors when in fact the database is - // in a consistent state. metaA is the one with the higher txid. - metaA := db.meta0 - metaB := db.meta1 - if db.meta1.txid > db.meta0.txid { - metaA = db.meta1 - metaB = db.meta0 - } - - // Use higher meta page if valid. Otherwise fallback to previous, if valid. - if err := metaA.validate(); err == nil { - return metaA - } else if err := metaB.validate(); err == nil { - return metaB - } - - // This should never be reached, because both meta1 and meta0 were validated - // on mmap() and we do fsync() on every write. - panic("bolt.DB.meta(): invalid meta pages") -} - -// allocate returns a contiguous block of memory starting at a given page. -func (db *DB) allocate(txid txid, count int) (*page, error) { - // Allocate a temporary buffer for the page. - var buf []byte - if count == 1 { - buf = db.pagePool.Get().([]byte) - } else { - buf = make([]byte, count*db.pageSize) - } - p := (*page)(unsafe.Pointer(&buf[0])) - p.overflow = uint32(count - 1) - - // Use pages from the freelist if they are available. - if p.id = db.freelist.allocate(txid, count); p.id != 0 { - return p, nil - } - - // Resize mmap() if we're at the end. - p.id = db.rwtx.meta.pgid - var minsz = int((p.id+pgid(count))+1) * db.pageSize - if minsz >= db.datasz { - if err := db.mmap(minsz); err != nil { - return nil, fmt.Errorf("mmap allocate error: %s", err) - } - } - - // Move the page id high water mark. - db.rwtx.meta.pgid += pgid(count) - - return p, nil -} - -// grow grows the size of the database to the given sz. -func (db *DB) grow(sz int) error { - // Ignore if the new size is less than available file size. - if sz <= db.filesz { - return nil - } - - // If the data is smaller than the alloc size then only allocate what's needed. - // Once it goes over the allocation size then allocate in chunks. - if db.datasz < db.AllocSize { - sz = db.datasz - } else { - sz += db.AllocSize - } - - // Truncate and fsync to ensure file size metadata is flushed. - // https://github.com/boltdb/bolt/issues/284 - if !db.NoGrowSync && !db.readOnly { - if runtime.GOOS != "windows" { - if err := db.file.Truncate(int64(sz)); err != nil { - return fmt.Errorf("file resize error: %s", err) - } - } - if err := db.file.Sync(); err != nil { - return fmt.Errorf("file sync error: %s", err) - } - } - - db.filesz = sz - return nil -} - -func (db *DB) IsReadOnly() bool { - return db.readOnly -} - -func (db *DB) freepages() []pgid { - tx, err := db.beginTx() - defer func() { - err = tx.Rollback() - if err != nil { - panic("freepages: failed to rollback tx") - } - }() - if err != nil { - panic("freepages: failed to open read only tx") - } - - reachable := make(map[pgid]*page) - nofreed := make(map[pgid]bool) - ech := make(chan error) - go func() { - for e := range ech { - panic(fmt.Sprintf("freepages: failed to get all reachable pages (%v)", e)) - } - }() - tx.checkBucket(&tx.root, reachable, nofreed, ech) - close(ech) - - var fids []pgid - for i := pgid(2); i < db.meta().pgid; i++ { - if _, ok := reachable[i]; !ok { - fids = append(fids, i) - } - } - return fids -} - -// Options represents the options that can be set when opening a database. -type Options struct { - // Timeout is the amount of time to wait to obtain a file lock. - // When set to zero it will wait indefinitely. This option is only - // available on Darwin and Linux. - Timeout time.Duration - - // Sets the DB.NoGrowSync flag before memory mapping the file. - NoGrowSync bool - - // Do not sync freelist to disk. This improves the database write performance - // under normal operation, but requires a full database re-sync during recovery. - NoFreelistSync bool - - // FreelistType sets the backend freelist type. There are two options. Array which is simple but endures - // dramatic performance degradation if database is large and framentation in freelist is common. - // The alternative one is using hashmap, it is faster in almost all circumstances - // but it doesn't guarantee that it offers the smallest page id available. In normal case it is safe. - // The default type is array - FreelistType FreelistType - - // Open database in read-only mode. Uses flock(..., LOCK_SH |LOCK_NB) to - // grab a shared lock (UNIX). - ReadOnly bool - - // Sets the DB.MmapFlags flag before memory mapping the file. - MmapFlags int - - // InitialMmapSize is the initial mmap size of the database - // in bytes. Read transactions won't block write transaction - // if the InitialMmapSize is large enough to hold database mmap - // size. (See DB.Begin for more information) - // - // If <=0, the initial map size is 0. - // If initialMmapSize is smaller than the previous database size, - // it takes no effect. - InitialMmapSize int - - // PageSize overrides the default OS page size. - PageSize int - - // NoSync sets the initial value of DB.NoSync. Normally this can just be - // set directly on the DB itself when returned from Open(), but this option - // is useful in APIs which expose Options but not the underlying DB. - NoSync bool - - // OpenFile is used to open files. It defaults to os.OpenFile. This option - // is useful for writing hermetic tests. - OpenFile func(string, int, os.FileMode) (*os.File, error) -} - -// DefaultOptions represent the options used if nil options are passed into Open(). -// No timeout is used which will cause Bolt to wait indefinitely for a lock. -var DefaultOptions = &Options{ - Timeout: 0, - NoGrowSync: false, - FreelistType: FreelistArrayType, -} - -// Stats represents statistics about the database. -type Stats struct { - // Freelist stats - FreePageN int // total number of free pages on the freelist - PendingPageN int // total number of pending pages on the freelist - FreeAlloc int // total bytes allocated in free pages - FreelistInuse int // total bytes used by the freelist - - // Transaction stats - TxN int // total number of started read transactions - OpenTxN int // number of currently open read transactions - - TxStats TxStats // global, ongoing stats. -} - -// Sub calculates and returns the difference between two sets of database 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 *Stats) Sub(other *Stats) Stats { - if other == nil { - return *s - } - var diff Stats - diff.FreePageN = s.FreePageN - diff.PendingPageN = s.PendingPageN - diff.FreeAlloc = s.FreeAlloc - diff.FreelistInuse = s.FreelistInuse - diff.TxN = s.TxN - other.TxN - diff.TxStats = s.TxStats.Sub(&other.TxStats) - return diff -} - -type Info struct { - Data uintptr - PageSize int -} - -type meta struct { - magic uint32 - version uint32 - pageSize uint32 - flags uint32 - root bucket - freelist pgid - pgid pgid - txid txid - checksum uint64 -} - -// validate checks the marker bytes and version of the meta page to ensure it matches this binary. -func (m *meta) validate() error { - if m.magic != magic { - return ErrInvalid - } else if m.version != version { - return ErrVersionMismatch - } else if m.checksum != 0 && m.checksum != m.sum64() { - return ErrChecksum - } - return nil -} - -// copy copies one meta object to another. -func (m *meta) copy(dest *meta) { - *dest = *m -} - -// write writes the meta onto a page. -func (m *meta) write(p *page) { - if m.root.root >= m.pgid { - panic(fmt.Sprintf("root bucket pgid (%d) above high water mark (%d)", m.root.root, m.pgid)) - } else if m.freelist >= m.pgid && m.freelist != pgidNoFreelist { - // TODO: reject pgidNoFreeList if !NoFreelistSync - panic(fmt.Sprintf("freelist pgid (%d) above high water mark (%d)", m.freelist, m.pgid)) - } - - // Page id is either going to be 0 or 1 which we can determine by the transaction ID. - p.id = pgid(m.txid % 2) - p.flags |= metaPageFlag - - // Calculate the checksum. - m.checksum = m.sum64() - - m.copy(p.meta()) -} - -// generates the checksum for the meta. -func (m *meta) sum64() uint64 { - var h = fnv.New64a() - _, _ = h.Write((*[unsafe.Offsetof(meta{}.checksum)]byte)(unsafe.Pointer(m))[:]) - return h.Sum64() -} - -// _assert will panic with a given formatted message if the given condition is false. -func _assert(condition bool, msg string, v ...interface{}) { - if !condition { - panic(fmt.Sprintf("assertion failed: "+msg, v...)) - } -} -- cgit v1.2.3-54-g00ecf