Merge pull request #24 from clzls/use_malloc

Use `malloc` in `fileHandlerImpl`

webui.nim

@@ -371,17 +371,19 @@ proc `bind`*(window: Window; element: string; `func`: proc (e: Event): bool) =
   )
 
 proc fileHandlerImpl(filename: cstring, length: ptr cint): pointer {.cdecl.} =
-  let content = cstring currHandler($filename)
+  let content = currHandler($filename)
 
-  #? maybe use webui_malloc
+  if content.len == 0:
+    return nil
 
-  # setting length is optional apparently
+  # Always set length for memory safety, especially binarys with '\0' inside
   length[] = cint content.len
 
-  if len($content) == 0:
-    return nil
+  # Use webui_malloc to ensure memory safety
+  let mem = bindings.malloc(csize_t content.len)
+  copyMem(mem, cstring content, content.len)
 
-  return cast[pointer](content)
+  return mem
 
 proc `fileHandler=`*(window: Window; handler: proc (filename: string): string) = 
   ## Set a custom handler to serve files.

webui/bindings.nim

@@ -225,7 +225,7 @@ proc free*(`ptr`: pointer) {.cdecl, importc: "webui_free".}
   ##  Safely free a buffer allocated by WebUI, for example when using 
   ##  `encode()`.
 
-proc malloc*(size: csize_t) {.cdecl, importc: "webui_malloc".}
+proc malloc*(size: csize_t): pointer {.cdecl, importc: "webui_malloc".}
   ##  Safely allocate memory using the WebUI memory management system.
   ##  It can be safely free using `free()`.