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authorEric Wong <e@80x24.org>2015-01-17 11:30:51 +0000
committerEric Wong <e@80x24.org>2015-01-19 09:56:52 +0000
commitb5bc0240f47dba01ff0a09263c210e5d391f88dc (patch)
tree8ae74163f66a575d36ba80acc615d6e37c116dc0 /lib/dtas/watchable.rb
parent8f07678251b20f41063cd0a8fbf81f3b4bd39967 (diff)
downloaddtas-b5bc0240f47dba01ff0a09263c210e5d391f88dc.tar.gz
This allows changes in the source YAML file to be reflected
immediately in player after the user saves the file in their
favorite $EDITOR.  Previously, a user would need to:

	1) start dtas-sourceedit, spawning $EDITOR
	2) edit the file
	3) save changes
	4) exit $EDITOR
	5) repeat starting from 1) until happy with the results

Now, the workflow allows avoiding the context switch between their
$EDITOR and terminal to restart dtas-sourcedit:

	1) start dtas-sourceedit, spawning $EDITOR
	2) edit the file
	3) save changes
	4) repeat starting from 1) until happy with the results
	5) exit $EDITOR

In my experience, this greatly speeds up tuning of the playback
change, giving all the repeatability and flexibility of editing text
files while having the immediacy of an interactive UI.

Keep in mind this can cause problems for those with auto-save
enabled in their $EDITOR buffer at inopportune times, so a
-N/--no-watch option is added.
Diffstat (limited to 'lib/dtas/watchable.rb')
-rw-r--r--lib/dtas/watchable.rb54
1 files changed, 54 insertions, 0 deletions
diff --git a/lib/dtas/watchable.rb b/lib/dtas/watchable.rb
new file mode 100644
index 0000000..d4c384c
--- /dev/null
+++ b/lib/dtas/watchable.rb
@@ -0,0 +1,54 @@
+# Copyright (C) 2014, all contributors <dtas-all@nongnu.org>
+# License: GPLv3 or later <https://www.gnu.org/licenses/gpl-3.0.txt>
+begin
+  require 'sleepy_penguin'
+rescue LoadError
+end
+
+# used to restart DTAS::Source::SplitFX processing in dtas-player
+# if the YAML file is edited
+module DTAS::Watchable
+  class InotifyReadableIter < SleepyPenguin::Inotify
+    def self.new
+      super(:CLOEXEC)
+    end
+
+    FLAGS = CLOSE_WRITE | MOVED_TO
+
+    def readable_iter
+      or_call = false
+      while event = take(true) # drain the buffer
+        if (event.mask & FLAGS) != 0 && @watching[1] == event.name
+          or_call = true
+        end
+      end
+      if or_call && @on_readable
+        @on_readable.call
+        :delete
+      else
+        :wait_readable
+      end
+    end
+
+    # we must watch the directory, since
+    def watch_file(path, blk)
+      @on_readable = blk
+      @watching = File.split(File.expand_path(path))
+      add_watch(@watching[0], FLAGS)
+    end
+  end
+
+  def watch_begin(blk)
+    @ino = InotifyReadableIter.new
+    @ino.watch_file(@infile, blk)
+    @ino
+  end
+
+  # Closing the inotify descriptor (instead of using inotify_rm_watch)
+  # is cleaner because it avoids EINVAL on race conditions in case
+  # a directory is deleted: https://lkml.org/lkml/2007/7/9/3
+  def watch_end(srv)
+    srv.wait_ctl(@ino, :delete)
+    @ino = @ino.close
+  end
+end if defined?(SleepyPenguin::Inotify)