pim: personal information management, starting with a calendar

A calendar as a file tree, and tools that only know the tree:

	events/date/yyyy/mm/dd/hhmm-summary	as lived
	events/uuid/<uid>/			as stored
	ctl query alarm changed

lib/cal owns all of that. A backend supplies events and, where its
protocol allows, takes changes back -- six methods. cmd/icalfs is the
first: it reads .ics files from a directory and nothing else, because
fetching is rc/fetch's job and hget already exists. That keeps
net/http out of the binary and makes a subscribed calendar and a local
one the same thing.

The tools are rc on purpose. If the tree needs a compiled program to be
useful, the tree is the wrong shape. Three things were added to the
tree because the rc port needed them: a path from an occurrence to its
event, epoch seconds beside RFC3339, and a numeric slot for all-day
events so test(1) can compare it.

ctl reports caps, so a tool can say "read only" instead of trying and
failing. A published .ics is read only: nowhere to PUT, and no
METHOD:REQUEST to reply to. CalDAV would be read write rsvp schedule,
and that is the next backend.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

1 files changed, 38 insertions, 0 deletions

diff --git a/pim/rc/calendars b/pim/rc/calendars
new file mode 100644
index 0000000..e1f191e
--- /dev/null
+++ b/pim/rc/calendars
@@ -0,0 +1,38 @@
+#!/bin/rc
+# pim/calendars -- name every mounted calendar, one per line.
+#
+# rc globs only metacharacters written literally in the source, so a
+# pattern held in a variable will not expand.  Every tool that works
+# across calendars enumerates them through here instead.
+rfork e
+
+mtpt=/mnt/pim
+long=()
+while(~ $1 -*){
+	switch($1){
+	case -m
+		mtpt=$2; shift
+	case -l
+		long=1
+	case *
+		echo 'usage: calendars [-m mtpt] [-l]' >[1=2]
+		exit usage
+	}
+	shift
+}
+# mntgen leaves the directory behind when a server goes away, so an
+# empty name is not a calendar. A live one answers for ctl.
+for(c in `{ls -p $mtpt/calendars >[2]/dev/null})
+	if(test -f $mtpt/calendars/$c/ctl){
+		if(~ $#long 0)
+			echo $c
+		if(! ~ $#long 0){
+			# caps says what the backend can do: a published .ics is
+			# read-only, with no iMIP path and nothing to write to
+			caps=`{sed -n 's/^caps //p' $mtpt/calendars/$c/ctl}
+			if(~ $#caps 0)
+				caps=unknown
+			echo $c^'	'^$"caps
+		}
+	}
+exit 0