restore.v

1//! Writing a tree back onto disk.2//!3//! A restore writes the target's files and deletes the tracked files the4//! target does not have. An ignored file already on disk is never overwritten5//! or deleted, and every file lands through a temp file and a rename, so an6//! interrupted restore leaves a readable tree rather than half-written files.78module snapshot910import os11import src.storage1213pub struct RestoreReport {14pub:15	written int16	removed int17}1819// restore_files writes `target` into the working tree and deletes the paths in20// `remove` (tracked files the target does not have). An ignored file already21// on disk is left as it is, even when the target saved an older copy: it may22// hold work no save has. A missing one is written. Every file lands through a23// temp file and a rename, so an interrupted restore leaves a readable tree24// rather than half-written files.25pub fn restore_files(store &storage.Store, root string, ig Ignore, target []FileEntry, remove []string) !RestoreReport {26	mut wanted := map[string]bool{}27	for entry in target {28		wanted[entry.path] = true29	}30	mut removed := 031	for path in remove {32		full := os.join_path(root, path)33		if !os.is_file(full) || ig.matches(path, false) || path in wanted {34			continue35		}36		os.rm(full)!37		removed++38		prune_empty_dirs(root, os.dir(full))39	}40	// A folder where a file belongs: gone if the removals emptied it, else it41	// holds ignored files, which are never touched. Refuse before writing, as42	// V's move would otherwise drop the file inside the folder.43	for entry in target {44		full := os.join_path(root, entry.path)45		if os.is_dir(full) {46			os.rmdir(full) or {47				return error('${entry.path} is a folder of ignored files where a saved file belongs — move it, then run the command again')48			}49		}50	}51	mut written := 052	for entry in target {53		if ig.matches(entry.path, false) && os.exists(os.join_path(root, entry.path)) {54			continue55		}56		data := store.get_object(entry.hash)!57		write_file(os.join_path(root, entry.path), data, entry.executable)!58		written++59	}60	return RestoreReport{61		written: written62		removed: removed63	}64}6566fn write_file(path string, data []u8, executable bool) ! {67	os.mkdir_all(os.dir(path), os.MkdirParams{})!68	tmp := '${path}.koh-tmp-${os.getpid()}'69	os.write_file_array(tmp, data)!70	mode := if executable { 0o755 } else { 0o644 }71	os.chmod(tmp, mode)!72	os.rename(tmp, path)!73}7475// prune_empty_dirs clears directories a restore emptied, never the repo root.76fn prune_empty_dirs(root string, dir string) {77	mut current := dir78	for current.len > root.len && current.starts_with(root) {79		if (os.ls(current) or { return }).len > 0 {80			return81		}82		os.rmdir(current) or { return }83		current = os.dir(current)84	}85}