Shared Source CLI Essentials

Chapter 4. Extracting Types from Assemblies

Types attain their full power as an integration mechanism when they are packaged in a form that can be easily transported from machine to machine and reconstituted safely. The CLI devotes a great deal of its design to enabling exactly this scenario, using a packaging approach based on assemblies . Assemblies are central to understanding components, since as we saw in the discussion of metadata, the component architecture of the CLI is data-driven: the data found in assemblies is a blueprint for all of the types that will populate the execution engine at runtime. Although such metadata can be synthesized directly at runtime, it is far more common to find it in the form of a file on disk, in which form it can propagate from machine to machine and from microprocessor to microprocessor, via traditional disk-to-disk copy or via network download.

Type Packaging

Assemblies are the basic unit of packaging and code security for the CLI runtime. The requirement that most influenced their design was the need for packaging that would allow self-contained components to be moved easily from location to location and yet still interoperate with high fidelity. To accommodate this, assemblies took on the following characteristics , which will serve to guide us further in our examination of the CLI:

Assemblies are self-describing

Assemblies, to enable data-driven execution, are completely self-descriptive and preserve full-fidelity metadata.

Assemblies ...