[Sbcl-devel] *default-pathname-defaults* (was Re: Dan's last two messages)

[Daniel B. <da...@te...>]

[ Incidentally, I expect to have only intermittent net connectivity -
if that - between about now and about next Sunday ]

Daniel Barlow <da...@te...> writes:

> ENSURE-DIRECTORIES-EXIST doesn't do this, yet it accesses the file
> system, so arguably it should

> (2) this doesn't actually help much as *default-pathname-defaults* is
> #P"".  My proposal is that it should be set to the value of
> (SB-EXT::DEFAULT-DIRECTORY) at startup and advertised as the standard
> way of "changing directory" - given that SB-EXT::DEFAULT-DIRECTORY
> isn't exported anyway, we need some such thing.

For what it's worth, I tried the simplest thing that might have worked:
(diff cut up by hand, may not apply automatically)

--- code/filesys.lisp   2001/05/19 00:13:14     1.13.2.1
+++ code/filesys.lisp   2001/05/19 00:56:52
@@ -1062,11 +1035,10 @@
 (defun ensure-directories-exist (pathspec &key verbose (mode #o777))
   #!+sb-doc
-  "Test whether the directories containing the specified file
-  actually exist, and attempt to create them if they do not.
-  The MODE argument is a CMUCL/SBCL-specific extension to control
-  the Unix permission bits."
-  (let* ((pathname (pathname pathspec))
+  "Tests whether the directories containing the specified file
+  actually exist, and attempts to create them if they do not.
+  Portable programs should avoid using the :MODE argument."
+  (let* ((pathname (merge-pathnames (pathname pathspec)))
         (pathname (if (typep pathname 'logical-pathname)
                       (translate-logical-pathname pathname)
                       pathname))
--- code/toplevel.lisp  2001/05/19 00:13:14     1.12.2.2
+++ code/toplevel.lisp  2001/05/19 00:56:54
@@ -299,7 +301,8 @@
        (options (rest *posix-argv*))) ; skipping program name
 
     (/show0 "done with outer LET in TOPLEVEL-INIT")
-  
+    (setf *default-pathname-defaults* (pathname (sb!ext::default-directory)))
+    (/show0 "initialized *default-pathname-defaults*")
     ;; FIXME: There are lots of ways for errors to happen around here
     ;; (e.g. bad command line syntax, or READ-ERROR while trying to
     ;; READ an --eval string). Make sure that they're handled

It builds fine, it rebuilds using itself fine.  I haven't re-enabled
the "." special case in UNIX-STAT, and, yes, I did run clean.sh first

(It doesn't pass the filesys.pure.test, but I think that's a problem
with the test, and it doesn't get on with common-lisp-controller, but
I think that's a problem with using relative pathnames in logical
hosts there: the MERGE-PATHNAMES spec says that the directory
component of default-pathname still gets merged even if pathname and
default-pathname are on different hosts, and that's what we're doing.
Rewriting system definitions to use absolute paths makes it much
happier.  Oh for italicisable email)

I think this approach - or something much like it - is the Right
Thing, and it looks so far like we can introduce it incrementally
without breaking everything too badly in the process.  One for 0.7?

> (3) found in the course of implementing (1), I realised that we
> currently have different behaviours for the :defaults argument to 
> make-pathname than for merge-pathnames. 

Per Kent Pitman, this is perfectly normal - desirable, even, and
should not be changed

In other news, I'm taking a laptop with me (the Alpha is a bit heavy)
with which I intend to look very sceptically at fd-stream.lisp.  I
think that a serve-event-like-thing could be accomplished a lot more
neatly if it infected fd-streams at a lower level - but there is
probably an efficiency tradeoff that needs thinking about.


-dan

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