Documentation
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Overview ¶
Package util provides utility functions for interacting with filesystems.
Index ¶
- Constants
- Variables
- func Atomic(path string, fn func(path string) error) (err error)
- func AtomicFile(path string, fn func(f *os.File) error) (err error)
- func CopyFile(source, sink string) error
- func CopyFileRangeTo(path string, offset, length int64, writer io.Writer) error
- func CopyFileTo(path string, writer io.Writer) error
- func Create(path string) (*os.File, error)
- func CreateFile(path string, flags int, mode os.FileMode) (*os.File, error)
- func DirExists(path string) (bool, error)
- func FileExists(path string) (bool, error)
- func FileSize(path string) (uint64, error)
- func Mkdir(path string, mode os.FileMode, parents, ignoreExists bool) error
- func OpenRandAccess(path string, start, end int64) (*os.File, error)
- func OpenSeqAccess(path string, start, end int64) (*os.File, error)
- func ReadIfProvided(path string) ([]byte, error)
- func ReadJSONFile(path string, data any) error
- func Remove(path string, ignoreNotExists bool) error
- func RemoveAll(path string) error
- func Sync(path string) error
- func Touch(path string) error
- func WriteAt(path string, data []byte, offset int64) error
- func WriteFile(path string, data []byte, mode os.FileMode) error
- func WriteJSONFile(path string, data any, mode os.FileMode) error
- func WriteTempFile(dir string, data []byte) (string, error)
- func WriteToFile(path string, reader io.Reader, mode os.FileMode) error
Constants ¶
const ( // DefaultFileMode represents the default file mode which will be used if a zero value file mode is provided for // operations which create new files. DefaultFileMode os.FileMode = 0o660 // DefaultDirMode represents the default file mode which will be used if a zero value file mode is provided for // operations which create new directories. DefaultDirMode os.FileMode = 0o770 )
Variables ¶
var ( // ErrNotFile is returned by 'FileExists' if a directory exists at the provided path. ErrNotFile = errors.New("not a file") // ErrNotDir is returned by 'DirExists' if a file exists at the provided path. ErrNotDir = errors.New("not a directory") )
Functions ¶
func Atomic ¶
Atomic will perform the provided function in an "atomic" fashion using the rename pattern.
NOTE: This only works to the degree that the underlying operating system guarantees that renames are atomic.
func AtomicFile ¶ added in v1.1.0
AtomicFile will perform the provided function in an "atomic" fashion, like Atomic. It is more efficient than Atomic as the temporary file is only opened once. The provided function must not close the file.
NOTE: This only works to the degree that the underlying operating system guarantees that renames are atomic.
func CopyFile ¶
CopyFile copies the source file to the sink file truncating it if it already exists.
NOTE: The sink file will be given the same permissions as the source file.
func CopyFileRangeTo ¶
CopyFileRangeTo is similar to 'CopyFileTo' but allows specifying an offset/length.
func CopyFileTo ¶
CopyFileTo copies all the data from the file at the provided path into the given writer.
func Create ¶
Create a new file at the provided path in read/write mode, any existing file will be truncated when opening.
func CreateFile ¶
CreateFile creates a new file (or truncates an existing one) at the provided path using the given flags/mode.
NOTE: If a zero value file mode is suppled, the default will be used.
func DirExists ¶
DirExists returns a boolean indicating whether a directory at the provided path exists.
func FileExists ¶
FileExists returns a boolean indicating whether a file at the provided path exists.
func Mkdir ¶
Mkdir creates a new directory with the provided mode and may optionally create all parent directories.
NOTE: If a zero value file mode is suppled, the default will be used.
func OpenRandAccess ¶
OpenRandAccess opens the provided file whilst advising the kernel that we'll be accessing the byte range from start to end with a random access pattern; this should decrease the pre-fetch amount and avoid bloating the page cache with data that we'll only be using once. If a zero start/end is provided kernels after 2.6.6 will treat this as "all the bytes through to the end of the file".
NOTE: This is advise to the kernel, the kernel provides no guarantees that it will honor/action the advise.
func OpenSeqAccess ¶
OpenSeqAccess opens the provided file whilst advising the kernel that we'll be accessing the byte range from start to end sequentially; this should increase the pre-fetch amount for this file. If a zero start/end is provided kernels after 2.6.6 will treat this as "all the bytes through to the end of the file".
NOTE: This is advise to the kernel, the kernel provides no guarantees that it will honor/action the advise.
func ReadIfProvided ¶
ReadIfProvided is the equvilent to 'os.ReadFile' but will return <nil>, <nil> if no path is provided.
func ReadJSONFile ¶
ReadJSONFile unmarshals data from the provided file into the given interface.
func Touch ¶
Touch is analogous to the unix 'touch' command, it updates the access/modified times of the file at the provided path creating it if it doesn't exist.
func WriteAt ¶
WriteAt writes data to the given offset in the file at the provided path.
NOTE: The file at the given path must already exist.
func WriteJSONFile ¶
WriteJSONFile marshals the provided interface and writes it to a file at the given path.
func WriteTempFile ¶
WriteTempFile writes out the provided data to a temporary file in the given directory (OS temporary directory if omitted) and returns the path to that file.
NOTE: It's the job of the caller to correctly handle cleaning up the file.
Types ¶
This section is empty.
Source Files