89 lines
2.8 KiB
Ruby
89 lines
2.8 KiB
Ruby
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module INotify
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# Watchers monitor a single path for changes,
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# specified by {INotify::Notifier#watch event flags}.
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# A watcher is usually created via \{Notifier#watch}.
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#
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# One {Notifier} may have many {Watcher}s.
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# The Notifier actually takes care of the checking for events,
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# via \{Notifier#run #run} or \{Notifier#process #process}.
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# The main purpose of having Watcher objects
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# is to be able to disable them using \{#close}.
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class Watcher
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# The {Notifier} that this Watcher belongs to.
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#
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# @return [Notifier]
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attr_reader :notifier
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# The path that this Watcher is watching.
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#
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# @return [String]
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attr_reader :path
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# The {INotify::Notifier#watch flags}
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# specifying the events that this Watcher is watching for,
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# and potentially some options as well.
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#
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# @return [Array<Symbol>]
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attr_reader :flags
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# The id for this Watcher.
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# Used to retrieve this Watcher from {Notifier#watchers}.
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#
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# @private
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# @return [Fixnum]
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attr_reader :id
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# Calls this Watcher's callback with the given {Event}.
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#
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# @private
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# @param event [Event]
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def callback!(event)
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@callback[event]
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end
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# Disables this Watcher, so that it doesn't fire any more events.
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#
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# @raise [SystemCallError] if the watch fails to be disabled for some reason
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def close
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if Native.inotify_rm_watch(@notifier.fd, @id) == 0
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@notifier.watchers.delete(@id)
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return
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end
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raise SystemCallError.new("Failed to stop watching #{path.inspect}",
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FFI.errno)
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end
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# Creates a new {Watcher}.
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#
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# @private
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# @see Notifier#watch
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def initialize(notifier, path, *flags, &callback)
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@notifier = notifier
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@callback = callback || proc {}
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@path = path
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@flags = flags.freeze
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@id = Native.inotify_add_watch(@notifier.fd, path.dup,
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Native::Flags.to_mask(flags))
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unless @id < 0
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@notifier.watchers[@id] = self
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return
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end
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raise SystemCallError.new(
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"Failed to watch #{path.inspect}" +
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case FFI.errno
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when Errno::EACCES::Errno; ": read access to the given file is not permitted."
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when Errno::EBADF::Errno; ": the given file descriptor is not valid."
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when Errno::EFAULT::Errno; ": path points outside of the process's accessible address space."
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when Errno::EINVAL::Errno; ": the given event mask contains no legal events; or fd is not an inotify file descriptor."
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when Errno::ENOMEM::Errno; ": insufficient kernel memory was available."
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when Errno::ENOSPC::Errno; ": The user limit on the total number of inotify watches was reached or the kernel failed to allocate a needed resource."
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else; ""
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end,
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FFI.errno)
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end
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end
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end
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