This update provides:
1) workaround around the build failures. In
summary, it forces the download of some packages during the build
process.
2) update the set of packages that should go inside the vendor
directory
3) Update the dockerfile to use go 1.10
Change-Id: I2bfd090ce0f25b0c10aa214755ae2da7e5384d60
diff --git a/vendor/github.com/coreos/bbolt/db.go b/vendor/github.com/coreos/bbolt/db.go
new file mode 100644
index 0000000..1223493
--- /dev/null
+++ b/vendor/github.com/coreos/bbolt/db.go
@@ -0,0 +1,1036 @@
+package bolt
+
+import (
+ "errors"
+ "fmt"
+ "hash/fnv"
+ "log"
+ "os"
+ "runtime"
+ "runtime/debug"
+ "strings"
+ "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
+
+// 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()
+
+// 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 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
+ file *os.File
+ lockfile *os.File // windows only
+ 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
+ freelist *freelist
+ stats Stats
+
+ 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) {
+ var db = &DB{opened: true}
+
+ // Set default options if no options are provided.
+ if options == nil {
+ options = DefaultOptions
+ }
+ db.NoGrowSync = options.NoGrowSync
+ db.MmapFlags = options.MmapFlags
+
+ // 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
+ }
+
+ // Open data file and separate sync handler for metadata writes.
+ db.path = path
+ var err error
+ if db.file, err = os.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, mode, !db.readOnly, options.Timeout); err != nil {
+ _ = db.close()
+ return nil, err
+ }
+
+ // Default values for test hooks
+ db.ops.writeAt = db.file.WriteAt
+
+ // Initialize the database if it doesn't exist.
+ if info, err := db.file.Stat(); err != nil {
+ return nil, err
+ } else if info.Size() == 0 {
+ // Initialize new files with meta pages.
+ if err := db.init(); err != nil {
+ return nil, err
+ }
+ } else {
+ // Read the first meta page to determine the page size.
+ var buf [0x1000]byte
+ if _, err := db.file.ReadAt(buf[:], 0); err == nil {
+ m := db.pageInBuffer(buf[:], 0).meta()
+ if err := m.validate(); err != nil {
+ // If we can't read the page size, we can assume it's the same
+ // as the OS -- 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.
+ db.pageSize = os.Getpagesize()
+ } else {
+ db.pageSize = int(m.pageSize)
+ }
+ }
+ }
+
+ // 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
+ }
+
+ // Read in the freelist.
+ db.freelist = newFreelist()
+ db.freelist.read(db.page(db.meta().freelist))
+
+ // Mark the database as opened and return.
+ return db, nil
+}
+
+// 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<<i {
+ return 1 << i, nil
+ }
+ }
+
+ // Verify the requested size is not above the maximum allowed.
+ if size > 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 {
+ // Set the page size to the OS page size.
+ db.pageSize = os.Getpagesize()
+
+ // 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.
+// All transactions must be closed before closing the database.
+func (db *DB) Close() error {
+ db.rwlock.Lock()
+ defer db.rwlock.Unlock()
+
+ db.metalock.Lock()
+ defer db.metalock.Unlock()
+
+ db.mmaplock.RLock()
+ defer db.mmaplock.RUnlock()
+
+ 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
+
+ // Free any pages associated with closed read-only transactions.
+ var minid txid = 0xFFFFFFFFFFFFFFFF
+ for _, t := range db.txs {
+ if t.meta.txid < minid {
+ minid = t.meta.txid
+ }
+ }
+ if minid > 0 {
+ db.freelist.release(minid - 1)
+ }
+
+ return t, nil
+}
+
+// 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 {
+ db.txs = append(db.txs[:i], db.txs[i+1:]...)
+ 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
+ }
+
+ if err := t.Rollback(); err != nil {
+ return err
+ }
+
+ return nil
+}
+
+// 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 {
+ if c.err != nil {
+ 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(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(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
+}
+
+// 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
+
+ // 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
+}
+
+// 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,
+}
+
+// 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 = other.TxN - s.TxN
+ diff.TxStats = s.TxStats.Sub(&other.TxStats)
+ return diff
+}
+
+func (s *Stats) add(other *Stats) {
+ s.TxStats.add(&other.TxStats)
+}
+
+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 {
+ 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...))
+ }
+}
+
+func warn(v ...interface{}) { fmt.Fprintln(os.Stderr, v...) }
+func warnf(msg string, v ...interface{}) { fmt.Fprintf(os.Stderr, msg+"\n", v...) }
+
+func printstack() {
+ stack := strings.Join(strings.Split(string(debug.Stack()), "\n")[2:], "\n")
+ fmt.Fprintln(os.Stderr, stack)
+}