Function GenerateDownloadChunks

internal/sessions/transfer.go:222–249

GenerateDownloadChunks generates shell commands that read sequential chunks of a file via dd+base64.

(filePath string, plan TransferPlan)

// GenerateDownloadChunks generates shell commands that read sequential chunks
// of a file via dd+base64.
func GenerateDownloadChunks(filePath string, plan TransferPlan) []DownloadChunk {
	if plan.Strategy == StrategyDirectTool || plan.TotalSize <= 0 {
		return nil
	}

	chunkSize := plan.ChunkSize
	if chunkSize <= 0 {
		chunkSize = defaultProfile.ChunkSizeBytes
	}

	var chunks []DownloadChunk
	for offset := 0; offset < plan.TotalSize; offset += chunkSize {
		size := chunkSize
		if offset+size > plan.TotalSize {
			size = plan.TotalSize - offset
		}

		cmd := fmt.Sprintf("dd if='%s' bs=1 skip=%d count=%d 2>/dev/null | base64", filePath, offset, size)

		chunks = append(chunks, DownloadChunk{
			Index:   len(chunks),
			Offset:  offset,
			Size:    size,
			Command: cmd,
		})
	}
	return chunks
}

// ---------------------------------------------------------------------------
// File size probe