TODO list for agedu
===================
- - 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.
+ - flexibility in the HTML report output mode: expose the internal
+ mechanism for configuring the output filenames, and allow the
+ user to request individual files with hyperlinks as if the other
+ files existed. (In particular, functionality of this kind would
+ enable other modes of use like the built-in --cgi mode, without
+ me having to anticipate them in detail.)
+
+ - non-ASCII character set support
+ + could usefully apply to --title and also to file names
+ + how do we determine the input charset? Via locale, presumably.
+ + how do we do translation? Importing my charset library is one
+ heavyweight option; alternatively, does the native C locale
+ mechanism provide enough functionality to do the job by itself?
+ + in HTML, we would need to decide on an _output_ character set,
+ specify it in a <meta http-equiv> tag, and translate to it from
+ the input locale
+ - one option is to make the output charset the same as the
+ input one, in which case all we need is to identify its name
+ for the <meta> tag
+ - the other option is to make the output charset UTF-8 always
+ and translate to that from everything else
+ - in the web server and CGI modes, it would probably be nicer
+ to move that <meta> tag into a proper HTTP header
+ + even in text mode we would want to parse the filenames in some
+ fashion, due to the unhelpful corner case of Shift-JIS Windows
+ (in which backslashes in the input string must be classified as
+ path separators or the second byte of a two-byte character)
+ - that's really painful, since it will impact string processing
+ of filenames throughout the code
+ - so perhaps a better approach would be to do locale processing
+ of filenames at _scan_ time, and normalise to UTF-8 in both
+ the index and dump files?
+ + involves incrementing the version of the dump-file format
+ + then paths given on the command line are translated
+ quickly to UTF-8 before comparing them against index paths
+ + and now the HTML output side becomes easy, though the text
+ output involves translating back again
+ + but what if the filenames aren't intended to be
+ interpreted in any particular character set (old-style
+ Unix semantics) or in a consistent one?
- we could still be using more of the information coming from
autoconf. Our config.h is defining a whole bunch of HAVE_FOOs for
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
- merely have to be prepared to open one of /proc/net/tcp or
- /proc/net/tcp6 as appropriate.
-
- run-time configuration in the HTTP server
* I think this probably works by having a configuration form, or
a link pointing to one, somewhere on the report page. If you
HTML. Then the former can be reused to produce very similar
reports in coloured plain text.
- - http://msdn.microsoft.com/en-us/library/ms724290.aspx suggest
- modern Windowses support atime-equivalents, so a Windows port is
- possible in principle.
- + For a full Windows port, would need to modify the current
- structure a lot, to abstract away (at least) memory-mapping of
- files, details of disk scan procedure, networking for httpd.
- Unclear what the right UI would be on Windows, too;
- command-line exactly as now might be considered just a
- _little_ unfriendly. Or perhaps not.
- + Alternatively, a much easier approach would be to write a
- Windows version of just the --scan-dump mode, which does a
- filesystem scan via the Windows API and generates a valid
- 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.
+ - abstracting away all the Unix calls so as to enable a full
+ Windows port. We can already do the difficult bit on Windows
+ (scanning the filesystem and retrieving atime-analogues).
+ Everything else is just coding - albeit quite a _lot_ of coding,
+ since the Unix assumptions are woven quite tightly into the
+ current code.
+ + If nothing else, it's unclear what the user interface properly
+ ought to be in a Windows port of agedu. A command-line job
+ exactly like the Unix version might be useful to some people,
+ but would certainly be strange and confusing to others.
- it might conceivably be useful to support a choice of indexing
- strategies. The current "continuous index" mechanism' tradeoff of
+ strategies. The current "continuous index" mechanism's 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
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.
+ index, the space saving is less compelling.
+
+ - A user requested what's essentially a VFS layer: given multiple
+ index files and a map of how they fit into an overall namespace,
+ we should be able to construct the right answers for any query
+ about the resulting aggregated hierarchy by doing at most
+ O(number of indexes * normal number of queries) work.
+
+ - Support for filtering the scan by ownership and permissions. The
+ index data structure can't handle this, so we can't build a
+ single index file admitting multiple subset views; but a user
+ suggested that the scan phase could record information about
+ ownership and permissions in the dump file, and then the indexing
+ phase could filter down to a particular sub-view - which would at
+ least allow the construction of various subset indices from one
+ dump file, without having to redo the full disk scan which is the
+ most time-consuming part of all.
~mdw / sgt / agedu / blobdiff