.patch-chez-gc-handler

#!/bin/sh

# TODO to manage all the arguments one by one in the same way as the first

SS="$1"

if [ ! -r "$SS" ] && ! SS="$(pack app-path "$SS")_app/$SS.ss" || [ ! -r "$SS" ]; then
  echo "Neither can't find a file '$1', nor a program with that name" >&2
  exit 2
fi

# It is important that we search and replace only places where the `collect-request-handler`
# is set, and not generated, so that patched compiler would produce code as the original one.
# That's why we use `^` at the beginning of the pattern.
ORIG_CRH="^(collect-request-handler (lambda () (collect) (blodwen-run-finalisers)))"

if ! grep -q "$ORIG_CRH" "$SS"; then
  echo "File '$SS' does not contain a handler to patch"
  exit 0
fi

CRH="(collect-request-handler
 (let* ([gc-counter 1]
        [log-radix 2]
        [radix-mask (sub1 (bitwise-arithmetic-shift 1 log-radix))]
        [major-gc-factor 2]
        [trigger-major-gc-allocated (* major-gc-factor (bytes-allocated))])
   (lambda ()
     (cond
       [(>= (bytes-allocated) trigger-major-gc-allocated)
        ;; Force a major collection if memory use has doubled
        (collect (collect-maximum-generation))
        (blodwen-run-finalisers)
        (set! trigger-major-gc-allocated (* major-gc-factor (bytes-allocated)))]
       [else
        ;; Imitate the built-in rule, but without ever going to a major collection
        (let ([this-counter gc-counter])
          (if (> (add1 this-counter)
                 (bitwise-arithmetic-shift-left 1 (* log-radix (sub1 (collect-maximum-generation)))))
              (set! gc-counter 1)
              (set! gc-counter (add1 this-counter)))
          (collect
           ;; Find the minor generation implied by the counter
           (let loop ([c this-counter] [gen 0])
             (cond
               [(zero? (bitwise-and c radix-mask))
                (loop (bitwise-arithmetic-shift-right c log-radix)
                      (add1 gen))]
               [else
                gen]))))]))))"
CRH="$(echo "$CRH" | tr '\n' '|' | sed 's/|/\\n/g')"

set -e # Now each falling command stops the script

echo "Patching '$SS'..."
sed -i "s/$ORIG_CRH/$CRH/" "$SS"
printf "Compiling the patched version... "
(echo "(parameterize ([optimize-level 3] [compile-file-message #f]) (compile-program \"$SS\"))" | chezscheme -q | sed 's/()/done/')