X-Git-Url: https://git.distorted.org.uk/~mdw/sgt/agedu/blobdiff_plain/c5c3510f485cb66603842effca3b0d9f57216983..14601b5d4222f2bee568e03eddf2f949b2a9d126:/TODO

diff --git a/TODO b/TODO
index 0f94d49..6046cec 100644
--- a/TODO
+++ b/TODO
@@ -1,24 +1,27 @@
 TODO list for agedu
 ===================
 
-Before it's non-embarrassingly releasable:
+ - stop trying to calculate an upper bound on the index file size.
+   Instead, just mmap it at initial size + delta, and periodically
+   re-mmap it during index building if it grows too big. If we run
+   out of address space, we'll hear about it eventually; and
+   computing upper bounds given the new optimised index tends to be
+   a factor of five out, which is bad because it'll lead to running
+   out of theoretical address space and erroneously reporting
+   failure long before we run out of it for real.
 
- - cross-Unix portability:
-    + use autoconf
-       * configure use of stat64
-       * configure use of /proc/net/tcp
-       * configure use of /dev/random
-       * configure use of Linux syscall magic replacing readdir
-          + later glibcs have fdopendir, hooray! So we can use that
-	    too, if it's available and O_NOATIME is too.
-       * what do we do elsewhere about _GNU_SOURCE?
-
- - New mode: --remove, to destroy the data file. Handy for
-   totally self-contained usage: "-s . -w -R".
-
- - man page, --version.
-
-Future possibilities:
+ - we could still be using more of the information coming from
+   autoconf. Our config.h is defining a whole bunch of HAVE_FOOs for
+   particular functions (e.g. HAVE_INET_NTOA, HAVE_MEMCHR,
+   HAVE_FNMATCH). We could usefully supply alternatives for some of
+   these functions (e.g. cannibalise the PuTTY wildcard matcher for
+   use in the absence of fnmatch, switch to vanilla truncate() in
+   the absence of ftruncate); where we don't have alternative code,
+   it would perhaps be polite to throw an error at configure time
+   rather than allowing the subsequent build to fail.
+    + however, I don't see anything here that looks very
+      controversial; IIRC it's all in POSIX, for one thing. So more
+      likely this should simply wait until somebody complains.
 
  - IPv6 support in the HTTP server
     * of course, Linux magic auth can still work in this context; we
@@ -66,3 +69,17 @@ Future possibilities:
       agedu dump file on standard output. Then one would simply feed
       that over the network connection of one's choice to the rest
       of agedu running on Unix as usual.
+
+ - it might conceivably be useful to support a choice of indexing
+   strategies. The current "continuous index" mechanism' tradeoff of
+   taking O(N log N) space in order to be able to support any age
+   cutoff you like is not going to be ideal for everybody. A second
+   more conventional "discrete index" mechanism which allows the
+   user to specify a number of fixed cutoffs and just indexes each
+   directory on those alone would undoubtedly be a useful thing for
+   large-scale users. This will require considerable thought about
+   how to make the indexers pluggable at both index-generation time
+   and query time.
+    * however, now we have the cut-down version of the continuous
+      index, it might be the case that the space gain is no longer
+      worthwhile.