Merge pull request #7 from Arnaz87/closure

Closure API

examples/loader.nim

@@ -16,13 +16,16 @@ if dll == nil:
 
 # Now let's try and get a symbol from it
 var procSym = dll.symAddr("hello")
+if procSym == nil:
+  echo "Could not get symbol for hello"
+  quit 1
 
 # We need to set up our call first. This procedure takes one int argument
 var
   cif: Tcif
   params: ParamList
 # The argument the procedure takes
-params[0] = type_sint64.addr
+params[0] = type_sint32.addr
 # Prepare the call, with the aforementioned params, and no return type
 if OK != prep_cif(cif, DEFAULT_ABI, 1, type_void.addr, params):
   echo "Something went wrong with preparing the statement"
@@ -30,14 +33,16 @@ if OK != prep_cif(cif, DEFAULT_ABI, 1, type_void.addr, params):
 
 # Now let's set up a list of arguments
 var args: ArgList
-var i = 100
+var i: int32 = 100
 args[0] = i.addr
 
 # And call the symbol with our argument
 call(cif, procSym, nil, args)
 
+
+
 # Let's do another one. This time without arguments, but with a return type
-if OK != prep_cif(cif, DEFAULT_ABI, 0, type_sint64.addr, params):
+if OK != prep_cif(cif, DEFAULT_ABI, 0, type_sint32.addr, params):
   echo "Something went wrong with preparing the statement"
   quit 1
 
@@ -45,7 +50,57 @@ if OK != prep_cif(cif, DEFAULT_ABI, 0, type_sint64.addr, params):
 var highFiveSym = dll.symAddr("highFive")
 
 # Set up the position of our return value and call the procedure
-var theFive = 0
+var theFive: int32 = 0
 call(cif, highFiveSym, theFive.addr, args)
 echo theFive
 
+
+
+
+# And yet another example. This one with a simple function argument
+params[0] = type_pointer.addr
+if OK != prep_cif(cif, DEFAULT_ABI, 1, type_void.addr, params):
+  echo "Something went wrong with preparing the statement"
+  quit 1
+
+var helloFancySym = dll.symAddr("helloFancy")
+if helloFancySym == nil:
+  echo "Could not get symbol for helloFancy"
+  quit 1
+
+# This is the function that will be called
+proc fancyTen(x: int32): int32 {.cdecl.} =
+  result = 10
+  echo "It was given, ", x
+
+var fancyTenPointer: pointer = fancyTen
+args[0] = fancyTenPointer.addr
+call(cif, helloFancySym, nil, args)
+
+
+
+# Now, let's build a function at runtime with the closure API
+
+proc uglyEleven(cif: var TCif, ret: pointer, args: UncheckedArray[pointer], user_data: pointer) {.cdecl.} =
+  #long int x = *(long int*)args[0];
+  var x = cast[ptr int32](args[0])[]
+  var c = cast[ptr int](user_data)[]
+  echo "Given: ", x, ", Context: ", c
+  cast[ptr int32](ret)[] = 11
+
+var bound: pointer = nil
+var closure: ptr Closure = closure_alloc(bound)
+
+# Initialize the cif
+if OK != prep_cif(cif, DEFAULT_ABI, 1, type_sint32.addr, params):
+  echo "Something went wrong with preparing the statement"
+  quit 1
+
+var user_data = 17
+
+if OK != prep_closure_loc(closure, cif, uglyEleven, user_data.addr, bound):
+  echo "Something went wrong initializing the closure"
+  quit 1
+
+var r = cast[proc (x: int32): int32 {.cdecl.}](bound)(15)
+echo "Result, ", r

examples/plugin.nim

@@ -1,7 +1,10 @@
 # Compile with: nim c --noMain --app:lib plugin.nim
-proc hello(x: int) {.exportc.} =
+proc hello(x: int32) {.cdecl, exportc, dynlib.} =
   echo "Hello world, ", x
 
-proc highFive(): int {.exportc.} =
+proc highFive(): int32 {.cdecl, exportc, dynlib.} =
   result = 5
   echo "Here you go!"
+
+proc helloFancy(f: proc (n: int32): int32 {.cdecl.}) {.exportc.} =
+  echo "Such fancyness, ", f(42)

libffi.nim

@@ -161,5 +161,30 @@ proc prep_cif*(cif: var TCif; abi: TABI; nargs: cuint; rtype: ptr Type;
 proc call*(cif: var TCif; fn, rvalue: pointer;
            avalue: ArgList) {.cdecl, importc: "ffi_call", mylib.}
 
+
+when defined(x8664):
+  const TRAMPOLINE_SIZE = 24
+elif defined(windows) and defined(x86):
+  const TRAMPOLINE_SIZE = 52
+elif defined(amd64) and defined(windows):
+  const TRAMPOLINE_SIZE = 29
+else:
+  const TRAMPOLINE_SIZE = 10
+
+type
+  ClosureProc = proc (cif: var TCif, ret: pointer, args: UncheckedArray[pointer], user_data: pointer) {.cdecl.}
+  Closure* {.pure, final.} = object
+    tramp: array[0..TRAMPOLINE_SIZE, uint8]
+    cif: ptr TCif
+    fun: ClosureProc
+    user_data: pointer
+
+proc closure_alloc*(size: int, code: var pointer): ptr Closure {.cdecl, importc: "ffi_closure_alloc", mylib.}
+# same but taking care of the size
+template closure_alloc*(code: var pointer): ptr Closure =
+  closure_alloc(sizeof(ClosureProc), code)
+proc closure_free*(closure: ptr Closure) {.cdecl, importc: "ffi_closure_free", mylib.}
+proc prep_closure_loc*(closure: ptr Closure, cif: var TCif, fun: ClosureProc, user_data: pointer, codeloc: pointer): Status {.cdecl, importc: "ffi_prep_closure_loc", mylib.}
+
 # Useful for eliminating compiler warnings
 ##define FFI_FN(f) ((void (*)(void))f)

libffi.nimble

@@ -1,5 +1,5 @@
 # Package
-version       = "1.0.1"
+version       = "1.0.2"
 author        = "Andreas Rumpf"
 description   = "libffi wrapper for Nim."
 license       = "MIT"