[This is preliminary documentation and subject to change.]
The FileCost action enables dynamic costing of standard installation actions.
None
The CostInitialize action must be executed before executing the FileCost action. The installer is then responsible for determining the actual disk space cost of every file in the File table, on a per-component basis, taking into account volume clustering and the presence of existing files that may need to be overwritten. All actions that consume or release disk space are considered. In case an existing file is found, a file version check is performed to determine whether the new file actually needs to be installed. If the existing file is an equal or greater version, the existing file is not overwritten and no disk space cost is incurred. In any case, the installer uses the results of version checking to set the install state of each file.
The FileCost action itself simply initializes cost calculation with the installer. Actual dynamic costing does not occur until the CostFinalize action is executed.