Since file links and directory links on Windows are disjoint, and the
difference is relevant for operations such as deleting a file,
`link-exists?` is not enough information. Add `file-or-directory-type`
to provide more information and also avoid separate calls to
`file-exists?`, `directory-exists?`, etc.
The `delete-directory/files` function now uses `file-or-directory-type`
so that it will work right with Windows directory links.
Relevant to #3288
Procedures in compiled code could not previously have source-location
paths that are managed through the write-relative and load-directory
configuration. Instead, paths were always converted to strings that
start "..." --- and those strings were sometimes incorrectly converted
back to paths in context information extracted from a continuation
mark set.
This commit takes advantage of changes to Chez Scheme `fasl-write` and
`fasl-read` (and related for compiling code) to lift paths out where
linklet-level marshaling can take care of them.
Sync with changes from cisco/ChezScheme. The specific code fragments
that are compressed and the chunks that are used for compression
remain essentially the same as before for Racket CS, but a different
organization at the Chez Scheme level takes over some of the work that
was on the Racket CS linklet layer, and load times may improve
slightly.
In CS, if you interrupt an especially tight non-tail recursion, such
as
(let loop ()
(cons 1 (loop)))
then the "context" view of the continuation (as recorded in a
continuation mark set) can take space that is a multiple of the size
of the continuation itself. That's a particular problem if the
too-deep recursion triggers the memory limit in DrRacket, because
DrRacket will then need a multiple of its current heap space to report
"out of memory".
(Note: Just keeping the continuation itself is not a good option,
because that may retain other data referenced by the continuation.)
This commit reduces the heap space used to gather a continuation
context, relying in part on new Chez Scheme support, but mostly it
limits the context length to roughly the same maximum as in BC. The BC
limit is an implementation artifact, but it turns out to have good
properties; informaiton on more than 64k continuation frames is rarely
useful. The limit could be a parameter, but a large built-in limit
seems likely good enough.
(Another note: Adding a limit argument to
`continuation-mark-set->context` doesn't help enough, because it's too
late by that point; too much memory has been used to repersent the
information that's in the mark set.)
The commit also tightens tracking of continuations for memory
accounting, reducing the chance that a thread's large continuation
will be charged to the wrong custodian.
samth said "I don't think the Friendly Environment policy should be thought of as part of copyright issues, or applying only to people who contribute code. Is there a different phrasing that would accomplish what you want here?" I have rephrased the reference to the Friendly Environment Policy and moved it before the License section to avoid confusion with copyright issues.
