mirror of https://github.com/hak5/bolt.git
75 lines
1.7 KiB
Go
75 lines
1.7 KiB
Go
package bolt
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import (
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"fmt"
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"os"
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"syscall"
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"time"
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"unsafe"
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)
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var odirect int
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// fdatasync flushes written data to a file descriptor.
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func fdatasync(f *os.File) error {
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return f.Sync()
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}
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// flock acquires an advisory lock on a file descriptor.
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func flock(f *os.File, _ time.Duration) error {
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return nil
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}
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// funlock releases an advisory lock on a file descriptor.
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func funlock(f *os.File) error {
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return nil
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}
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// mmap memory maps a DB's data file.
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// Based on: https://github.com/edsrzf/mmap-go
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func mmap(db *DB, sz int) error {
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// Truncate the database to the size of the mmap.
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if err := db.file.Truncate(int64(sz)); err != nil {
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return fmt.Errorf("truncate: %s", err)
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}
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// Open a file mapping handle.
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sizelo := uint32(sz >> 32)
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sizehi := uint32(sz & 0xffffffff)
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h, errno := syscall.CreateFileMapping(syscall.Handle(db.file.Fd()), nil, syscall.PAGE_READONLY, sizelo, sizehi, nil)
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if h == 0 {
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return os.NewSyscallError("CreateFileMapping", errno)
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}
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// Create the memory map.
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addr, errno := syscall.MapViewOfFile(h, syscall.FILE_MAP_READ, 0, 0, uintptr(sz))
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if addr == 0 {
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return os.NewSyscallError("MapViewOfFile", errno)
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}
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// Close mapping handle.
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if err := syscall.CloseHandle(syscall.Handle(h)); err != nil {
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return os.NewSyscallError("CloseHandle", err)
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}
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// Convert to a byte array.
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db.data = ((*[maxMapSize]byte)(unsafe.Pointer(addr)))
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db.datasz = sz
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return nil
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}
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// munmap unmaps a pointer from a file.
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// Based on: https://github.com/edsrzf/mmap-go
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func munmap(db *DB) error {
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if db.data == nil {
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return nil
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}
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addr := (uintptr)(unsafe.Pointer(&db.data[0]))
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if err := syscall.UnmapViewOfFile(addr); err != nil {
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return os.NewSyscallError("UnmapViewOfFile", err)
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}
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return nil
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}
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