89 lines
3.3 KiB
Racket
89 lines
3.3 KiB
Racket
#lang syndicate
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(require racket/file)
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(require racket/serialize)
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(require operational-transformation)
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(require operational-transformation/text/simple-document)
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(require syndicate/protocol/advertise)
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(require/activate syndicate/drivers/tcp)
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(require/activate syndicate/drivers/line-reader)
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(struct proposed-op (p) #:prefab)
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(struct accepted-op (p) #:prefab)
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(struct client-seen-up-to (revision) #:prefab)
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(define cmdline-port (make-parameter 5888))
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(define cmdline-filename (make-parameter "info.rkt"))
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(spawn (field [state (make-server (simple-document
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(if (file-exists? (cmdline-filename))
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(begin (log-info "loading ~v" (cmdline-filename))
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(file->string (cmdline-filename)))
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(begin (log-info "will create ~v" (cmdline-filename))
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""))))])
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(assert (extract-snapshot (state)))
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(define/query-set client-seen-revs (client-seen-up-to $rev) rev)
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(field [oldest-needed-rev #f])
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(begin/dataflow
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(define min-rev
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(or (for/fold [(min-rev #f)] [(rev (client-seen-revs))]
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(min (or min-rev rev) rev))
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(server-state-revision (state))))
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(when (not (equal? (oldest-needed-rev) min-rev))
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(oldest-needed-rev min-rev)
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(state (forget-operation-history (state) min-rev))))
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(begin/dataflow
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(display-to-file (simple-document-text (server-state-document (state)))
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(cmdline-filename)
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#:exists 'replace))
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(on (message (proposed-op $p))
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(state (incorporate-operation-from-client (state) p))
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(define sp (extract-operation (state)))
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(when sp (send! (accepted-op sp)))))
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(spawn (define s (tcp-listener (cmdline-port)))
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(on-start (log-info "listening on port ~v" (cmdline-port)))
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(assert (advertise (observe (tcp-channel _ s _))))
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(during/spawn (advertise (tcp-channel $c s _))
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(assert (advertise (tcp-channel s c _)))
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(on-start (log-info "~a: connected" c))
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(on-stop (log-info "~a: disconnected" c))
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(connection-react c s (cmdline-filename))))
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(define (connection-react c s filename)
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(define (output v)
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;; (log-info "~a: sending them ~v" c v)
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(define p (open-output-bytes))
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(write (serialize v) p)
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(newline p)
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(send! (tcp-channel s c (get-output-bytes p))))
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(field [seen-up-to 0])
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(assert (client-seen-up-to (seen-up-to)))
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(on-start
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(output filename)
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(let-event [(asserted ($ snapshot (server-snapshot _ _)))]
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(output snapshot)
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(seen-up-to (server-snapshot-revision snapshot))
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(react (on (message (accepted-op $p))
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(output p)))))
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(on (message (tcp-channel-line c s $line))
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(match (deserialize (read (open-input-bytes line)))
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[(? number? n) (seen-up-to n)]
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[(? pending-operation? p) (send! (proposed-op p))])))
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(module+ main
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(require racket/cmdline)
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(command-line
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#:once-each
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[("-p" "--port") server-port ((format "Server port (default ~v)" (cmdline-port)))
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(cmdline-port (string->number server-port))]
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#:args (filename)
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(cmdline-filename filename)))
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