146 lines
4.1 KiB
GDScript
146 lines
4.1 KiB
GDScript
class_name PortableFileGuard
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extends RefCounted
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const MAX_PORTABLE_FILE_BYTES := 16 * 1024 * 1024
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static func hash_file(path: String) -> String:
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if not FileAccess.file_exists(path):
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return ""
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var file := FileAccess.open(path, FileAccess.READ)
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if file == null or file.get_length() > MAX_PORTABLE_FILE_BYTES:
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return ""
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var bytes := file.get_buffer(file.get_length())
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file.close()
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return hash_bytes(bytes)
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static func hash_bytes(bytes: PackedByteArray) -> String:
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var context := HashingContext.new()
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if context.start(HashingContext.HASH_SHA256) != OK:
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return ""
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if context.update(bytes) != OK:
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return ""
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return context.finish().hex_encode()
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static func read_bytes(path: String, maximum_bytes: int = MAX_PORTABLE_FILE_BYTES) -> PackedByteArray:
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if not FileAccess.file_exists(path):
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return PackedByteArray()
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var file := FileAccess.open(path, FileAccess.READ)
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if file == null or file.get_length() > maximum_bytes:
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return PackedByteArray()
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var bytes := file.get_buffer(file.get_length())
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file.close()
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return bytes
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static func write_guarded(
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path: String,
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bytes: PackedByteArray,
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expected_hash: String,
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conflict_directory: String,
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device_id: String,
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) -> Dictionary:
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var current_exists := FileAccess.file_exists(path)
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var current_hash := hash_file(path) if current_exists else ""
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if current_hash != expected_hash:
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var conflict_path := _write_conflict_copy(
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path, bytes, conflict_directory, device_id
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)
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return {
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"ok": false,
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"conflict": true,
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"hash": expected_hash,
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"conflict_path": conflict_path,
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"message": (
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"This file changed on another device.\n"
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+ "Your current data was preserved as a conflict copy."
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),
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}
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if not _ensure_parent(path):
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return {"ok": false, "conflict": false, "hash": expected_hash}
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var temporary := path + ".tmp"
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var backup := path + ".backup"
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var file := FileAccess.open(temporary, FileAccess.WRITE)
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if file == null:
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return {"ok": false, "conflict": false, "hash": expected_hash}
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file.store_buffer(bytes)
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file.flush()
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var write_error := file.get_error()
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file.close()
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if write_error != OK:
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_remove(temporary)
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return {"ok": false, "conflict": false, "hash": expected_hash}
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_remove(backup)
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if current_exists and not _rename(path, backup):
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_remove(temporary)
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return {"ok": false, "conflict": false, "hash": expected_hash}
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if not _rename(temporary, path):
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if current_exists:
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_rename(backup, path)
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return {"ok": false, "conflict": false, "hash": expected_hash}
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_remove(backup)
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return {
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"ok": true,
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"conflict": false,
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"hash": hash_bytes(bytes),
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"conflict_path": "",
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}
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static func has_syncthing_conflict(directory: String) -> bool:
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var access := DirAccess.open(directory)
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if access == null:
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return false
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access.list_dir_begin()
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var name := access.get_next()
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while not name.is_empty():
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var lower := name.to_lower()
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if "sync-conflict" in lower or ".syncthing." in lower:
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access.list_dir_end()
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return true
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name = access.get_next()
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access.list_dir_end()
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return false
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static func _write_conflict_copy(
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canonical_path: String,
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bytes: PackedByteArray,
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conflict_directory: String,
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device_id: String,
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) -> String:
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if DirAccess.make_dir_recursive_absolute(conflict_directory) != OK:
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return ""
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var filename := canonical_path.get_file()
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var safe_device := device_id.left(16)
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var timestamp := Time.get_datetime_string_from_system().replace(":", "-")
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var destination := conflict_directory.path_join(
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"%s.local-%s-%s" % [filename, safe_device, timestamp]
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)
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var file := FileAccess.open(destination, FileAccess.WRITE)
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if file == null:
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return ""
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file.store_buffer(bytes)
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file.flush()
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var ok := file.get_error() == OK
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file.close()
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return destination if ok else ""
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static func _ensure_parent(path: String) -> bool:
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var parent := path.get_base_dir()
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return (
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DirAccess.dir_exists_absolute(parent)
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or DirAccess.make_dir_recursive_absolute(parent) == OK
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)
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static func _rename(from_path: String, to_path: String) -> bool:
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return DirAccess.rename_absolute(from_path, to_path) == OK
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static func _remove(path: String) -> void:
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if FileAccess.file_exists(path):
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DirAccess.remove_absolute(path)
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