alien: a test and docs for free-callback

core/alien/alien-docs.factor

@@ -60,6 +60,13 @@ $nl
 
 { <alien> <displaced-alien> alien-address } related-words
 
+HELP: free-callback
+{ $values { "alien" alien } }
+{ $description "Releases the callback heap memory allocated for an alien callback. " }
+{ $warning "If the callback is invoked (either from C or Factor) after it has been freed, then Factor may crash." } ;
+
+{ <callback> free-callback } related-words
+
 HELP: alien-address
 { $values { "c-ptr" c-ptr } { "addr" "a non-negative integer" } }
 { $description "Outputs the address of an alien." }

core/alien/alien-tests.factor

@@ -1,6 +1,6 @@
-USING: accessors alien alien.accessors alien.syntax byte-arrays arrays
+USING: accessors alien alien.accessors alien.c-types alien.libraries
-kernel kernel.private namespaces tools.test sequences libc math
+alien.syntax arrays byte-arrays continuations fry kernel kernel.private layouts
-system prettyprint layouts alien.libraries sets ;
+libc math namespaces prettyprint sequences sets system tools.test ;
 FROM: namespaces => set ;
 IN: alien.tests
 
@@ -85,3 +85,17 @@ f initialize-test set-global
 [ 7575 ] [ initialize-test [ 7575 ] initialize-alien ] unit-test
 
 [ { BAD-ALIEN } ] [ { BAD-ALIEN BAD-ALIEN BAD-ALIEN } members ] unit-test
+
+! Generate callbacks until the whole callback-heap is full, then free
+! them. Do it ten times in a row for good measure.
+: produce-until-error ( quot -- error seq )
+    '[ [ @ t ] [ f ] recover ] [ ] produce ; inline
+
+SYMBOL: foo
+
+: fill-and-free-callback-heap ( -- )
+    [ \ foo 33 <callback> ] produce-until-error nip [ free-callback ] each ;
+
+[ ] [
+    10 [ fill-and-free-callback-heap ] times
+] unit-test