spdx 3.0: Rework how SPDX aliases are linked

The SPDX code needs to be able to look up an Element by its SPDX ID,
locating the file that (should) contain the SPDX ID and opening it for
parsing. Previously, the code would do this be hashing each Element
SPDX ID and Alias, and the creating a symbolic link to the file that
contains the element with a name of the hash.

This worked well as it was possible to look up any arbitrary SPDX ID or
alias by simply hashing it and following the symbolic link to get the
file. However, the down side of this approach is that it creates a lot
of symbolic links, since it will make one or two per Element in the
document. This can be a problem when using SPDX_INCLUDE_SOURCES, for
example.

This change reworks this strategy so that the only Element that gets a
symbolic link based on the hash is the singular SpdxDocument that is
create for each file. All other Elements are assigned an alias with a
special prefix that encodes the hash of SpdxDocument alias. Thus, when
attempting to look up an arbitrary alias, the code sees the special
prefix, extract the hash, opens the file based on the symlink with that
hash name, then finds the matching Element in the file. This drastically
reduces the number of symbolic links by making only one per file.

This also means that the custom link extension can be removed since it
is now superfluous.

(From OE-Core rev: 838d64c09657ac53175737fc4e7fd6f01f3dcf47)

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

0 files changed, 0 insertions, 0 deletions