Artifact [36c908a8e9]

Artifact 36c908a8e9e31cd9857b3b2079391577ba6abf0bad5fc821255b9fe2791bea08:

• File cli/repo_delta.go — part of check-in [38eddf43f1] at 2026-10-11 23:34:08 on branch main — fix(delta): refuse a source or target of 2^32 bytes or more in Create (#279) (#320)

  The delta format holds integers below 2^32 only, so a producer must not write a target length or copy offset at or past that. Create now returns ErrTooLarge for such inputs; Deltify then stores the content whole, as fossil does when a delta is not worthwhile, and the other callers propagate the error. Apply's header check becomes >= so it refuses exactly what Create will not write. The bound is tested on lengths, as a direct test needs a 4 GiB input. (user: [email protected], size: 1729) [annotate] [blame] [check-ins using]

package cli

import (
	"fmt"
	"os"

	"github.com/danmestas/go-libfossil/internal/delta"
)

// RepoDeltaCmd groups delta create/apply operations.
type RepoDeltaCmd struct {
	Create RepoDeltaCreateCmd `cmd:"" help:"Create a delta between two files"`
	Apply  RepoDeltaApplyCmd  `cmd:"" help:"Apply a delta to a source file"`
}

// RepoDeltaCreateCmd creates a delta between two files.
type RepoDeltaCreateCmd struct {
	Source string `arg:"" help:"Source (original) file"`
	Target string `arg:"" help:"Target (new) file"`
	Output string `short:"o" help:"Output file (default: stdout)"`
}

func (c *RepoDeltaCreateCmd) Run(g *Globals) error {
	src, err := os.ReadFile(c.Source)
	if err != nil {
		return fmt.Errorf("reading source: %w", err)
	}
	tgt, err := os.ReadFile(c.Target)
	if err != nil {
		return fmt.Errorf("reading target: %w", err)
	}

	d, err := delta.Create(src, tgt)
	if err != nil {
		return err
	}

	if c.Output != "" {
		return os.WriteFile(c.Output, d, 0o644)
	}
	os.Stdout.Write(d)
	return nil
}

// RepoDeltaApplyCmd applies a delta to a source file.
type RepoDeltaApplyCmd struct {
	Source string `arg:"" help:"Source (original) file"`
	Delta  string `arg:"" help:"Delta file"`
	Output string `short:"o" help:"Output file (default: stdout)"`
}

func (c *RepoDeltaApplyCmd) Run(g *Globals) error {
	src, err := os.ReadFile(c.Source)
	if err != nil {
		return fmt.Errorf("reading source: %w", err)
	}
	d, err := os.ReadFile(c.Delta)
	if err != nil {
		return fmt.Errorf("reading delta: %w", err)
	}

	result, err := delta.Apply(src, d)
	if err != nil {
		return fmt.Errorf("applying delta: %w", err)
	}

	if c.Output != "" {
		return os.WriteFile(c.Output, result, 0o644)
	}
	os.Stdout.Write(result)
	return nil
}