File system

The ZeroInstall.Store.FileSystem namespace provides interfaces and methods for building and reading file system structures.

The IBuilder interface represents a implementation directory being constructed.
IForwardOnlyBuilder is a more limited subset, that only allows the addition of files but not the modification of files that have already been added.

There are various implementations of IBuilder:

• DirectoryBuilder for creating a real on-disk directory
• ManifestBuilder for calculating an in-memory manifest of the directory
• ZeroInstall.Archives.Builders for creating archives (.zip, .tar, etc.)

Implementation store

When adding an implementation to an IImplementationStore the caller is provided an IBuilder via a callback:

store.Add(manifestDigest, builder =>
{
    builder.AddFile(...);
    builder.AddFile(...);
});

This allows the implementation store to control how and where the implementation gets constructed (usually via a composite of a DirectoryBuilder and a ManifestBuilder).

Retrieval methods

BuilderExtensions and BuilderExtensions provide extension methods for applying RetrievalMethods to an IBuilder. These methods internally pass the IBuilder to ReadDirectory, ZeroInstall.Archives.Extractors, etc..