class INotify::Notifier
Notifier wraps a single instance of inotify. It's possible to have more than one instance, but usually unnecessary.
@example
# Create the notifier notifier = INotify::Notifier.new # Run this callback whenever the file path/to/foo.txt is read notifier.watch("path/to/foo.txt", :access) do puts "Foo.txt was accessed!" end # Watch for any file in the directory being deleted # or moved out of the directory. notifier.watch("path/to/directory", :delete, :moved_from) do |event| # The #name field of the event object contains the name of the affected file puts "#{event.name} is no longer in the directory!" end # Nothing happens until you run the notifier! notifier.run
Constants
- RECURSIVE_BLACKLIST
A list of directories that should never be recursively watched.
-
Files in `/dev/fd` sometimes register as directories, but are not enumerable.
-
Attributes
A hash from {Watcher} ids to the instances themselves.
@private @return [{Fixnum => Watcher}]
Public Class Methods
Creates a new {Notifier}.
@return [Notifier] @raise [SystemCallError] if inotify failed to initialize for some reason
# File lib/rb-inotify/notifier.rb, line 51 def initialize @running = Mutex.new @pipe = IO.pipe @watchers = {} fd = Native.inotify_init unless fd < 0 @handle = IO.new(fd) return end raise SystemCallError.new( "Failed to initialize inotify" + case FFI.errno when Errno::EMFILE::Errno; ": the user limit on the total number of inotify instances has been reached." when Errno::ENFILE::Errno; ": the system limit on the total number of file descriptors has been reached." when Errno::ENOMEM::Errno; ": insufficient kernel memory is available." else; "" end, FFI.errno) end
Public Instance Methods
Close the notifier.
@raise [SystemCallError] if closing the underlying file descriptor fails.
# File lib/rb-inotify/notifier.rb, line 261 def close stop @handle.close @watchers.clear end
The underlying file descriptor for this notifier. This is a valid OS file descriptor, and can be used as such (except under JRuby – see {#to_io}).
@return [Fixnum]
# File lib/rb-inotify/notifier.rb, line 43 def fd @handle.fileno end
Blocks until there are one or more filesystem events that this notifier has watchers registered for. Once there are events, the appropriate callbacks are called and this function returns.
@see run
# File lib/rb-inotify/notifier.rb, line 251 def process read_events.each do |event| event.callback! event.flags.include?(:ignored) && event.notifier.watchers.delete(event.watcher_id) end end
Blocks until there are one or more filesystem events that this notifier has watchers registered for. Once there are events, returns their {Event} objects.
This can return an empty list if the watcher was closed elsewhere.
{#run} or {#process} are ususally preferable to calling this directly.
# File lib/rb-inotify/notifier.rb, line 274 def read_events size = Native::Event.size + Native.fpathconf(fd, Native::Flags::PC_NAME_MAX) + 1 tries = 1 begin data = readpartial(size) rescue SystemCallError => er # EINVAL means that there's more data to be read # than will fit in the buffer size raise er unless er.errno == Errno::EINVAL::Errno && tries < 5 size *= 2 tries += 1 retry end return [] if data.nil? events = [] cookies = {} while event = Event.consume(data, self) events << event next if event.cookie == 0 cookies[event.cookie] ||= [] cookies[event.cookie] << event end cookies.each {|c, evs| evs.each {|ev| ev.related.replace(evs - [ev]).freeze}} events end
Starts the notifier watching for filesystem events. Blocks until {#stop} is called.
@see process
# File lib/rb-inotify/notifier.rb, line 225 def run @running.synchronize do @stop = false process until @stop end end
Stop watching for filesystem events. That is, if we're in a {#run} loop, exit out as soon as we finish handling the events.
# File lib/rb-inotify/notifier.rb, line 236 def stop @stop = true @pipe.last.write "." @running.synchronize do # no-op: we just needed to wait until the lock was available end end
Returns a Ruby IO object wrapping the underlying file descriptor. Since this file descriptor is fully functional (except under JRuby), this IO object can be used in any way a Ruby-created IO object can. This includes passing it to functions like `#select`.
Note that this always returns the same IO object. Creating lots of IO objects for the same file descriptor can cause some odd problems.
**This is not supported under JRuby**. JRuby currently doesn't use native file descriptors for the IO object, so we can't use this file descriptor as a stand-in.
@return [IO] An IO object wrapping the file descriptor @raise [NotImplementedError] if this is being called in JRuby
# File lib/rb-inotify/notifier.rb, line 89 def to_io @handle end
Watches a file or directory for changes, calling the callback when there are. This is only activated once {#process} or {#run} is called.
**Note that by default, this does not recursively watch subdirectories of the watched directory**. To do so, use the `:recursive` flag.
## Flags
`:access` : A file is accessed (that is, read).
`:attrib` : A file's metadata is changed (e.g. permissions, timestamps, etc).
`:close_write` : A file that was opened for writing is closed.
`:close_nowrite` : A file that was not opened for writing is closed.
`:modify` : A file is modified.
`:open` : A file is opened.
### Directory-Specific Flags
These flags only apply when a directory is being watched.
`:moved_from` : A file is moved out of the watched directory.
`:moved_to` : A file is moved into the watched directory.
`:create` : A file is created in the watched directory.
`:delete` : A file is deleted in the watched directory.
`:delete_self` : The watched file or directory itself is deleted.
`:move_self` : The watched file or directory itself is moved.
### Helper Flags
These flags are just combinations of the flags above.
`:close` : Either `:close_write` or `:close_nowrite` is activated.
`:move` : Either `:moved_from` or `:moved_to` is activated.
`:all_events` : Any event above is activated.
### Options Flags
These flags don't actually specify events. Instead, they specify options for the watcher.
`:onlydir` : Only watch the path if it's a directory.
`:dont_follow` : Don't follow symlinks.
`:mask_add` : Add these flags to the pre-existing flags for this path.
`:oneshot` : Only send the event once, then shut down the watcher.
`:recursive` : Recursively watch any subdirectories that are created.
Note that this is a feature of rb-inotify, rather than of inotify itself, which can only watch one level of a directory. This means that the {Event#name} field will contain only the basename of the modified file. When using `:recursive`, {Event#absolute_name} should always be used.
@param path [String] The path to the file or directory @param flags [Array<Symbol>] Which events to watch for @yield [event] A block that will be called
whenever one of the specified events occur
@yieldparam event [Event] The Event object containing information
about the event that occured
@return [Watcher] A Watcher set up to watch this path for these events @raise [SystemCallError] if the file or directory can't be watched,
e.g. if the file isn't found, read access is denied, or the flags don't contain any events
# File lib/rb-inotify/notifier.rb, line 191 def watch(path, *flags, &callback) return Watcher.new(self, path, *flags, &callback) unless flags.include?(:recursive) dir = Dir.new(path) dir.each do |base| d = File.join(path, base) binary_d = d.respond_to?(:force_encoding) ? d.dup.force_encoding('BINARY') : d next if binary_d =~ /\/\.\.?$/ # Current or parent directory next if RECURSIVE_BLACKLIST.include?(d) next if flags.include?(:dont_follow) && File.symlink?(d) next if !File.directory?(d) watch(d, *flags, &callback) end dir.close rec_flags = [:create, :moved_to] return watch(path, *((flags - [:recursive]) | rec_flags)) do |event| callback.call(event) if flags.include?(:all_events) || !(flags & event.flags).empty? next if (rec_flags & event.flags).empty? || !event.flags.include?(:isdir) begin watch(event.absolute_name, *flags, &callback) rescue Errno::ENOENT # If the file has been deleted since the glob was run, we don't want to error out. end end end
Private Instance Methods
Same as IO#readpartial, or as close as we need.
# File lib/rb-inotify/notifier.rb, line 305 def readpartial(size) readable, = select([@handle, @pipe.first]) return nil if readable.include?(@pipe.first) @handle.readpartial(size) rescue Errno::EBADF # If the IO has already been closed, reading from it will cause # Errno::EBADF. nil end