util

Documentation

Index

• func AtomicWriteFile(path string, data []byte, defaultMode os.FileMode) error
• func RelativizePaths(text, baseDir string) string
• func Truncate(s string, maxRunes int) string
• type ShellSpec
  • func DetectShell() (ShellSpec, error)
  • func NewShellCommand(command string) (*exec.Cmd, ShellSpec, error)
  • func NewShellCommandContext(ctx context.Context, command string) (*exec.Cmd, ShellSpec, error)

Functions

func AtomicWriteFile

func AtomicWriteFile(path string, data []byte, defaultMode os.FileMode) error

AtomicWriteFile writes data to path via a temp file in the same directory, fsync's it, and renames it into place. If path already exists, the existing file's mode is preserved; otherwise defaultMode is used.

This avoids two failure modes of os.WriteFile(path, data, mode):

1. A crash between O_TRUNC and the final write leaves the user's source file truncated/empty.
2. The hard-coded mode silently downgrades 0755 scripts and 0600 secrets to 0644.

See locks.md S4.

func RelativizePaths

func RelativizePaths(text, baseDir string) string

RelativizePaths replaces absolute paths under baseDir with relative paths ("./"). It handles two cases:

• baseDir + separator + suffix → "./" + suffix
• baseDir as an exact standalone token → "."

The second case uses boundary checking to avoid false matches (e.g. "/Users/proj" should not match inside "/Users/proj-backup").

func Truncate

func Truncate(s string, maxRunes int) string

Truncate truncates a string to maxRunes runes, appending "..." if truncated. Uses []rune to avoid UTF-8 multi-byte truncation.

Types

type ShellSpec

type ShellSpec struct {
	Path string
	Args []string
	Name string
}

func DetectShell

func DetectShell() (ShellSpec, error)

func NewShellCommand

func NewShellCommand(command string) (*exec.Cmd, ShellSpec, error)

func NewShellCommandContext

func NewShellCommandContext(ctx context.Context, command string) (*exec.Cmd, ShellSpec, error)