I’m working on a project that needs to recursively find every file in a
directory structure and I found some code to get started with at:
https://www.rosettacode.org/wiki/Walk_a_directory/Recursively#Forth
It is not doing what it is supposed to do and I hope to improve on it, but I’ve
run into a stumbling block.
I can’t seem to be able to open directories to see if I’ve fallen into a
symbolic loop.
For example, a symbolic link pointing to “../” will cause it to overflow real
quickly.
The only solution I can think of is to look for duplicate names, but that has
far too many false positives.
Here’s my code, and I’m hoping someone can suggest an alternative:
: $append ( from len to -- ) 2DUP >R >R COUNT + SWAP MOVE R> R@ C@ + R> C! ;
: dots? ( name len -- ? )
\ 2dup s" ." compare 0= if 2drop true exit then
\ s" .." compare 0= if true exit then
drop c@ [char] . = if true exit then
false ;
: (ls-r) ( dir len -- )
pad c@ >r dup >r pad count >r >r pad $append s" /" pad $append
r> r> 2dup + 1- r> 2 + search nip nip if
." -> loop detected" r> pad c! exit then ( duplicate)
pad count open-dir if drop r> pad c! exit then ( dirid)
begin
dup pad count + 256 rot read-dir throw
while
pad count + over dots? 0= if \ ignore current and parent dirs
cr dup pad count rot + type
pad count + swap recurse
else drop then
repeat
drop r> pad c!
close-dir throw
;
: ls-r ( dir len -- ) 0 pad c! (ls-r) ;
s" ." ls-r cr
DaR
