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Diffstat (limited to 'third_party/git/git-gui/lib/chord.tcl')
| -rw-r--r-- | third_party/git/git-gui/lib/chord.tcl | 158 |
1 files changed, 0 insertions, 158 deletions
diff --git a/third_party/git/git-gui/lib/chord.tcl b/third_party/git/git-gui/lib/chord.tcl deleted file mode 100644 index e21e7d3d0b79..000000000000 --- a/third_party/git/git-gui/lib/chord.tcl +++ /dev/null @@ -1,158 +0,0 @@ -# Simple Chord for Tcl -# -# A "chord" is a method with more than one entrypoint and only one body, such -# that the body runs only once all the entrypoints have been called by -# different asynchronous tasks. In this implementation, the chord is defined -# dynamically for each invocation. A SimpleChord object is created, supplying -# body script to be run when the chord is completed, and then one or more notes -# are added to the chord. Each note can be called like a proc, and returns -# immediately if the chord isn't yet complete. When the last remaining note is -# called, the body runs before the note returns. -# -# The SimpleChord class has a constructor that takes the body script, and a -# method add_note that returns a note object. Since the body script does not -# run in the context of the procedure that defined it, a mechanism is provided -# for injecting variables into the chord for use by the body script. The -# activation of a note is idempotent; multiple calls have the same effect as -# a simple call. -# -# If you are invoking asynchronous operations with chord notes as completion -# callbacks, and there is a possibility that earlier operations could complete -# before later ones are started, it is a good practice to create a "common" -# note on the chord that prevents it from being complete until you're certain -# you've added all the notes you need. -# -# Example: -# -# # Turn off the UI while running a couple of async operations. -# lock_ui -# -# set chord [SimpleChord::new { -# unlock_ui -# # Note: $notice here is not referenced in the calling scope -# if {$notice} { info_popup $notice } -# } -# -# # Configure a note to keep the chord from completing until -# # all operations have been initiated. -# set common_note [$chord add_note] -# -# # Activate notes in 'after' callbacks to other operations -# set newnote [$chord add_note] -# async_operation $args [list $newnote activate] -# -# # Communicate with the chord body -# if {$condition} { -# # This sets $notice in the same context that the chord body runs in. -# $chord eval { set notice "Something interesting" } -# } -# -# # Activate the common note, making the chord eligible to complete -# $common_note activate -# -# At this point, the chord will complete at some unknown point in the future. -# The common note might have been the first note activated, or the async -# operations might have completed synchronously and the common note is the -# last one, completing the chord before this code finishes, or anything in -# between. The purpose of the chord is to not have to worry about the order. - -# SimpleChord class: -# Represents a procedure that conceptually has multiple entrypoints that must -# all be called before the procedure executes. Each entrypoint is called a -# "note". The chord is only "completed" when all the notes are "activated". -class SimpleChord { - field notes - field body - field is_completed - field eval_ns - - # Constructor: - # set chord [SimpleChord::new {body}] - # Creates a new chord object with the specified body script. The - # body script is evaluated at most once, when a note is activated - # and the chord has no other non-activated notes. - constructor new {i_body} { - set notes [list] - set body $i_body - set is_completed 0 - set eval_ns "[namespace qualifiers $this]::eval" - return $this - } - - # Method: - # $chord eval {script} - # Runs the specified script in the same context (namespace) in which - # the chord body will be evaluated. This can be used to set variable - # values for the chord body to use. - method eval {script} { - namespace eval $eval_ns $script - } - - # Method: - # set note [$chord add_note] - # Adds a new note to the chord, an instance of ChordNote. Raises an - # error if the chord is already completed, otherwise the chord is - # updated so that the new note must also be activated before the - # body is evaluated. - method add_note {} { - if {$is_completed} { error "Cannot add a note to a completed chord" } - - set note [ChordNote::new $this] - - lappend notes $note - - return $note - } - - # This method is for internal use only and is intentionally undocumented. - method notify_note_activation {} { - if {!$is_completed} { - foreach note $notes { - if {![$note is_activated]} { return } - } - - set is_completed 1 - - namespace eval $eval_ns $body - delete_this - } - } -} - -# ChordNote class: -# Represents a note within a chord, providing a way to activate it. When the -# final note of the chord is activated (this can be any note in the chord, -# with all other notes already previously activated in any order), the chord's -# body is evaluated. -class ChordNote { - field chord - field is_activated - - # Constructor: - # Instances of ChordNote are created internally by calling add_note on - # SimpleChord objects. - constructor new {c} { - set chord $c - set is_activated 0 - return $this - } - - # Method: - # [$note is_activated] - # Returns true if this note has already been activated. - method is_activated {} { - return $is_activated - } - - # Method: - # $note activate - # Activates the note, if it has not already been activated, and - # completes the chord if there are no other notes awaiting - # activation. Subsequent calls will have no further effect. - method activate {} { - if {!$is_activated} { - set is_activated 1 - $chord notify_note_activation - } - } -} |