WIP

src/coffi/ffi.clj

@@ -157,14 +157,15 @@
   "Gets the primitive type that is used to pass as an argument for the `type`.
 
   This is for objects which are passed to native functions as primitive types,
-  but which need additional logic to be performed during serialization.
+  but which need additional logic to be performed during serialization and
+  deserialization.
 
-  Returns nil for any type "
+  Returns nil for any type which does not have a primitive representation."
   (fn [type] type))
 
 (defmethod primitive-type :default
   [type]
-  (contains? primitive-types type))
+  (primitive-types type))
 
 (defmethod primitive-type ::c-string
   [_type]
@@ -191,20 +192,37 @@
   [type]
   (java-prim-layout type MemorySegment))
 
+(defn size-of
+  "The size in bytes of the given `type`."
+  [type]
+  (let [layout ^MemoryLayout (c-layout type)]
+    (.byteSize
+     (cond-> layout
+       (qualified-keyword? layout) ^MemoryLayout c-layout))))
+
+(defn alloc-instance
+  "Allocates a memory segment for the given `type`."
+  ([type] (alloc-instance type (ResourceScope/newImplicitScope)))
+  ([type scope] (MemorySegment/allocateNative ^long (size-of type) ^ResourceScope scope)))
+
 (defmulti serialize*
   "Constructs a serialized version of the `obj` and returns it.
 
   Any new allocations made during the serialization should be tied to the given
   `scope`, except in extenuating circumstances.
 
-  This method should only be implemented for types serialize to primitives."
+  This method should only be implemented for types that serialize to primitives."
   (fn
     #_{:clj-kondo/ignore [:unused-binding]}
     [obj type scope]))
 
-(defmethod serialize* ::c-string
-  [obj _type scope]
-  (address-of (CLinker/toCString (str obj) ^ResourceScope scope)))
+(defmethod serialize* :default
+  [obj type _scope]
+  (if (primitive-type type)
+    obj
+    (throw (ex-info "Attempted to serialize a non-primitive type with primitive methods"
+                    {:type type
+                     :object obj}))))
 
 (defmulti serialize-into
   "Writes a serialized version of the `obj` to the given `segment`.
@@ -222,6 +240,10 @@
     [obj type segment scope]
     type))
 
+(defmethod serialize* ::c-string
+  [obj _type scope]
+  (address-of (CLinker/toCString (str obj) ^ResourceScope scope)))
+
 (defmethod serialize-into :default
   [obj type segment scope]
   (let [new-type (c-layout type)]
@@ -310,7 +332,7 @@
   [segment _type]
   (MemoryAccess/getAddress segment))
 
-(defmulti deserialize
+(defmulti deserialize*
   "Deserializes a primitive object into a Clojure data structure.
 
   This is intended for use with types that are returned as a primitive but which
@@ -320,7 +342,7 @@
     [obj type]
     type))
 
-(defmethod deserialize :default
+(defmethod deserialize* :default
   [obj _type]
   obj)
 
@@ -328,24 +350,26 @@
   [segment type]
   (-> segment
       (deserialize-from ::pointer)
-      (deserialize type)))
+      (deserialize* type)))
 
-(defmethod deserialize ::c-string
+(defmethod deserialize* ::c-string
   [obj _type]
   (CLinker/toJavaString obj))
 
-(defn size-of
-  "The size in bytes of the given `type`."
-  [type]
-  (let [layout ^MemoryLayout (c-layout type)]
-    (.byteSize
-     (cond-> layout
-       (qualified-keyword? layout) ^MemoryLayout c-layout))))
+(defn serialize
+  [])
 
-(defn alloc-instance
-  "Allocates a memory segment for the given `type`."
-  ([type] (alloc-instance type (ResourceScope/newImplicitScope)))
-  ([type scope] (MemorySegment/allocateNative ^long (size-of type) ^ResourceScope scope)))
+(defn deserialize
+  "Deserializes an arbitrary type regardless of if it is primitive.
+
+  For types which have a primitive representation, this deserializes the
+  primitive representation. For types which do not, this deserializes out of
+  a [[MemorySegment]]."
+  [obj type]
+  ((if (primitive-type type)
+     deserialize*
+     deserialize-from)
+   obj type))
 
 (defn serialize
   "Serializes the `obj` into a newly-allocated [[MemorySegment]]."
@@ -392,6 +416,50 @@
   [address method-type function-descriptor]
   (.downcallHandle (CLinker/getInstance) address method-type function-descriptor))
 
+(s/def ::defcfn-args
+  (s/cat :name simple-symbol?
+         :doc (s/? string?)
+         :symbol (s/nonconforming
+                  (s/or :string string?
+                        :symbol simple-symbol?))
+         :native-arglist (s/coll-of qualified-keyword? :kind vector?)
+         :return-type qualified-keyword?
+         :fn-tail (s/?
+                   (s/cat :arglist (s/coll-of simple-symbol? :kind vector?)
+                          :body (s/* any?)))))
+
+(defmacro defcfn
+  {:arglists '([name docstring? symbol arg-types ret-type arglist & body])}
+  [& args]
+  (let [args (s/conform ::defcfn-args args)
+        scope (gensym "scope")
+        arg-syms (repeatedly (count (:native-arglist args)) #(gensym "arg"))]
+    `(let [args-types# ~(:native-arglist args)
+           ret-type# ~(:return-type args)
+           downcall# (downcall-handle
+                      (find-symbol ~(:symbol args))
+                      (method-type args-types# ret-type#)
+                      (function-descriptor args-types# ret-type#))
+           ~(:name args) (fn [& args#]
+                           (with-open [~scope (stack-scope)]
+                             (let [[~@arg-syms] (map #(serialize ))]
+                               (.invoke downcall# ~@arg-syms))))
+           fun# ~(if (:fn-tail args)
+                   `(fn ~(-> args :fn-tail :arglist)
+                      ~@(-> args :fn-tail :body))
+                   (:name args))]
+       (def
+         ~(vary-meta (:name args)
+                     update :arglists
+                     (fn [old-list]
+                       (or old-list
+                           (list
+                            (or (-> args :fn-tail :arglist)
+                                (mapv (comp symbol name)
+                                      (:native-arglist args)))))))
+         ~@(list (:doc args))
+         fun#))))
+
 (comment
 
   (let [args-types [::c-string]
@@ -403,7 +471,7 @@
         strlen (fn [str]
                  (with-open [scope (stack-scope)]
                    (let [arg1 (serialize (nth args-types 0) str scope)]
-                     (deserialize (.invoke downcall arg1) ret-type))))]
+                     (deserialize* (.invoke downcall arg1) ret-type))))]
     (def
       ^{:arglists '([str])}
       strlen