Add a notmuch widget (#92)

README.md

@@ -398,6 +398,20 @@ Supported platforms: GNU/Linux, FreeBSD.
     `${down_b}`, `${up_b}`, `${down_kb}`, `${up_kb}`, `${down_mb}`, `${up_mb}`,
     `${down_gb}`, `${up_gb}`.
 
+### vicious.widgets.notmuch
+
+Provides a message count according to an arbitrary Notmuch query.
+
+Supported platforms: platform independent.
+
+Argument: the query that is passed to Notmuch. For instance:
+`tag:inbox AND tag:unread` returns the number of unread messages with
+tag "inbox".
+
+Returns a table with string keys containing:
+* `${count}`: the count of messages that match the query
+
+
 ### vicious.widgets.org
 
 Provides agenda statistics for Emacs org-mode.

widgets/notmuch_all.lua

@@ -0,0 +1,38 @@
+-- notmuch_all - count messages that match a notmuch query
+-- Copyright (C) 2019  Enric Morales <me@enric.me>
+--
+-- This file is part of Vicious.
+--
+-- Vicious is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as
+-- published by the Free Software Foundation, either version 2 of the
+-- License, or (at your option) any later version.
+--
+-- Vicious is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU Affero General Public License for more details.
+--
+-- You should have received a copy of the GNU Affero General Public License
+-- along with Vicious.  If not, see <https://www.gnu.org/licenses/>.
+
+local tonumber = tonumber
+local helpers = require("vicious.helpers")
+local spawn = require("vicious.spawn")
+
+
+local notmuch = {}
+
+local function parse(stdout, stderr, exitreason, exitcode)
+    local output = { count = "N/A" }
+    if exitcode == 0 then output.count = tonumber(stdout) end
+    return output
+end
+
+function notmuch.async(format, warg, callback)
+    local cmd = ("notmuch count '^%s'"):format(warg)
+
+    spawn.easy_async(cmd, function (...) callback(parse(...)) end)
+end
+
+return helpers.setasyncall(notmuch)