Support custom streams with file name info

[simonferquel]

Many operations involved in rewriting debug symbols assume the rewritten assembly base stream is a FileStream to get file name information. This may not always be the case.

To cover this, this changes the way file name is resolved so that a custom stream implementing IHaveAFileName can be understood by Cecil.

Signed-off-by: Simon Ferquel [email protected]

[sschoener]

To add to this: This callsite in particular will write out an empty PDB path unless you write out to a file. This is undesirable in scenarios where you modify the assembly in memory and write to a MemoryStream which is later copied to to a FileStream. The net effect is that the resulting assembly will contain an empty PDB path. (I'm not sure what the best solution to this is, but this is the problem we are seeing.)

[jbevain]

Hey folks; Yeah I know that part is horrible.

Thanks for starting this discussion. I might not take this PR as is, but I'll think about how I want to fix this and get back to this PR.

Thanks again.