From 2e5967d2cd5dfbea2c62e05753eb7586964362d5 Mon Sep 17 00:00:00 2001
From: Nicholas Gates <nick@nickgates.com>
Date: Mon, 30 Oct 2023 09:27:41 +0000
Subject: [PATCH] CallArgs struct

---
 pydust/src/pytypes.zig    |  8 ++++----
 pydust/src/trampoline.zig | 43 ++++++++++++++++++++++++---------------
 2 files changed, 31 insertions(+), 20 deletions(-)

diff --git a/pydust/src/pytypes.zig b/pydust/src/pytypes.zig
index 421955a3..c60eaa1e 100644
--- a/pydust/src/pytypes.zig
+++ b/pydust/src/pytypes.zig
@@ -272,9 +272,9 @@ fn Slots(comptime definition: type, comptime name: [:0]const u8) type {
                 const kwargs = if (pykwargs) |pk| py.PyDict.unchecked(.{ .py = pk }) else null;
 
                 const init_args = tramp.Trampoline(Args).unwrapCallArgs(args, kwargs) catch return -1;
-                defer funcs.deinitArgs(Args, init_args);
+                defer init_args.deinit();
 
-                tramp.coerceError(definition.__init__(self, init_args)) catch return -1;
+                tramp.coerceError(definition.__init__(self, init_args.argsStruct)) catch return -1;
             } else if (sig.selfParam) |_| {
                 tramp.coerceError(definition.__init__(self)) catch return -1;
             } else {
@@ -364,9 +364,9 @@ fn Slots(comptime definition: type, comptime name: [:0]const u8) type {
 
             const self = tramp.Trampoline(sig.selfParam.?).unwrap(py.PyObject{ .py = pyself }) catch return null;
             const call_args = tramp.Trampoline(sig.argsParam.?).unwrapCallArgs(args, kwargs) catch return null;
-            defer funcs.deinitArgs(sig.argsParam.?, call_args);
+            defer call_args.deinit();
 
-            const result = tramp.coerceError(definition.__call__(self, call_args)) catch return null;
+            const result = tramp.coerceError(definition.__call__(self, call_args.argsStruct)) catch return null;
             return (py.createOwned(result) catch return null).py;
         }
     };
diff --git a/pydust/src/trampoline.zig b/pydust/src/trampoline.zig
index dc308988..3e877466 100644
--- a/pydust/src/trampoline.zig
+++ b/pydust/src/trampoline.zig
@@ -275,27 +275,38 @@ pub fn Trampoline(comptime T: type) type {
 
         // Unwrap the call args into a Pydust argument struct, borrowing references to the Python objects
         // but instantiating the args slice and kwargs map containers.
-        // The caller is responsible for invoking funcs.deinitArgs on the returned struct.
-        pub inline fn unwrapCallArgs(pyargs: ?py.PyTuple, pykwargs: ?py.PyDict) PyError!T {
-            var kwargs = py.Kwargs.init(py.allocator);
-            if (pykwargs) |kw| {
-                var iter = kw.itemsIterator();
-                while (iter.next()) |item| {
-                    const key: []const u8 = try (try py.PyString.checked(item.k)).asSlice();
-                    try kwargs.put(key, item.v);
+        // The caller is responsible for invoking deinit on the returned struct.
+        pub inline fn unwrapCallArgs(pyargs: ?py.PyTuple, pykwargs: ?py.PyDict) PyError!ZigCallArgs {
+            return ZigCallArgs.unwrap(pyargs, pykwargs);
+        }
+
+        const ZigCallArgs = struct {
+            argsStruct: T,
+
+            pub fn unwrap(pyargs: ?py.PyTuple, pykwargs: ?py.PyDict) PyError!T {
+                var kwargs = py.Kwargs.init(py.allocator);
+                if (pykwargs) |kw| {
+                    var iter = kw.itemsIterator();
+                    while (iter.next()) |item| {
+                        const key: []const u8 = try (try py.PyString.checked(item.k)).asSlice();
+                        try kwargs.put(key, item.v);
+                    }
                 }
-            }
 
-            const args = try py.allocator.alloc(py.PyObject, if (pyargs) |a| a.length() else 0);
-            defer py.allocator.free(args);
-            if (pyargs) |a| {
-                for (0..a.length()) |i| {
-                    args[i] = try a.getItem(py.PyObject, i);
+                const args = try py.allocator.alloc(py.PyObject, if (pyargs) |a| a.length() else 0);
+                if (pyargs) |a| {
+                    for (0..a.length()) |i| {
+                        args[i] = try a.getItem(py.PyObject, i);
+                    }
                 }
+
+                return .{ .argsStruct = funcs.unwrapArgs(T, args, kwargs) };
             }
 
-            return funcs.unwrapArgs(T, args, kwargs);
-        }
+            pub fn deinit(self: @This()) void {
+                funcs.deinitArgs(self.argsStruct);
+            }
+        };
     };
 }