From feb22ff7ce57f5d32431b024b135a62a595555dc Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Thu, 25 Jun 2026 04:57:56 +0530
Subject: [PATCH] More work on slangc

---
 kitty/shaders/compiler.cpp | 157 ++++++++++++++++++++++++++++++++++++-
 kitty/slangc.pyi           |   6 ++
 2 files changed, 161 insertions(+), 2 deletions(-)
 create mode 100644 kitty/slangc.pyi

diff --git a/kitty/shaders/compiler.cpp b/kitty/shaders/compiler.cpp
index e7afbe05f..21b499099 100644
--- a/kitty/shaders/compiler.cpp
+++ b/kitty/shaders/compiler.cpp
@@ -18,19 +18,172 @@
 
 using namespace slang;
 
+class ScopedPyObject {  // {{{
+private:
+    PyObject* ptr;
+
+public:
+    // Default constructor
+    ScopedPyObject() : ptr(nullptr) {}
+
+    // Constructor that takes ownership of a PyObject*
+    // Set 'is_strong_ref' to false if you are passing a borrowed reference
+    explicit ScopedPyObject(PyObject* p, bool is_strong_ref = true) : ptr(p) {
+        if (!is_strong_ref && ptr) {
+            Py_INCREF(ptr);
+        }
+    }
+
+    // Destructor automatically decrements the reference count
+    ~ScopedPyObject() {
+        Py_XDECREF(ptr);
+    }
+
+    // Delete copy operations to prevent accidental double-decref
+    ScopedPyObject(const ScopedPyObject&) = delete;
+    ScopedPyObject& operator=(const ScopedPyObject&) = delete;
+
+    // Move constructor transfers ownership
+    ScopedPyObject(ScopedPyObject&& other) noexcept : ptr(other.ptr) {
+        other.ptr = nullptr;
+    }
+
+    // Move assignment operator
+    ScopedPyObject& operator=(ScopedPyObject&& other) noexcept {
+        if (this != &other) {
+            Py_XDECREF(ptr);
+            ptr = other.ptr;
+            other.ptr = nullptr;
+        }
+        return *this;
+    }
+
+    // Allow assignment directly from a raw PyObject* (assumes strong reference)
+    ScopedPyObject& operator=(PyObject* p) {
+        Py_XDECREF(ptr);
+        ptr = p;
+        return *this;
+    }
+
+    // Smart pointer operators
+    PyObject* get() const { return ptr; }
+    PyObject* operator->() const { return ptr; }
+    explicit operator bool() const { return ptr != nullptr; }
+
+    // Release ownership without changing the ref count (returns raw pointer)
+    PyObject* release() {
+        PyObject* temp = ptr;
+        ptr = nullptr;
+        return temp;
+    }
+
+    // Safely reset to a new raw pointer
+    void reset(PyObject* p = nullptr, bool is_strong_ref = true) {
+        Py_XDECREF(ptr);
+        ptr = p;
+        if (!is_strong_ref && ptr) {
+            Py_INCREF(ptr);
+        }
+    }
+}; // }}}
+
+typedef struct GlobalSession {
+    PyObject_HEAD
+
+    Slang::ComPtr<IGlobalSession> ptr;
+} GlobalSession;
+
+static std::string
+get_slang_result_string(SlangResult result) {
+    switch (result) {
+        case SLANG_OK: return "SLANG_OK: Operation succeeded.";
+        case SLANG_FAIL: return "SLANG_FAIL: Generic operational failure.";
+        case SLANG_E_NOT_AVAILABLE: return "SLANG_E_NOT_AVAILABLE: The requested feature or interface is not available.";
+        case SLANG_E_NOT_IMPLEMENTED: return "SLANG_E_NOT_IMPLEMENTED: The feature has not been implemented.";
+        case SLANG_E_INVALID_ARG: return "SLANG_E_INVALID_ARG: One or more arguments are invalid.";
+        case SLANG_E_OUT_OF_MEMORY: return "SLANG_E_OUT_OF_MEMORY: The compiler ran out of memory.";
+        case SLANG_E_BUFFER_TOO_SMALL: return "SLANG_E_BUFFER_TOO_SMALL: The destination buffer is too small to hold the data.";
+        case SLANG_E_UNINITIALIZED: return "SLANG_E_UNINITIALIZED: A component or object was used without initialization.";
+        case SLANG_E_TIME_OUT: return "SLANG_E_TIME_OUT: The compilation or operation timed out.";
+        // Internal status codes often returned by compile steps
+        default:
+            if (result < 0) return "SLANG_ERROR_UNKNOWN: Code (0x" + std::to_string(result) + ")";
+            return "SLANG_STATUS_UNKNOWN: Code (0x" + std::to_string(result) + ")";
+    }
+}
+
+static PyObject *Error = nullptr;
+
+static void
+set_python_error(SlangResult r, const char *msg, PyObject *exc_class = nullptr) {
+    if (exc_class == nullptr) exc_class = Error;
+    PyErr_Format(exc_class, "%s: %s", msg, get_slang_result_string(r).c_str());
+}
+
+static PyObject*
+new_gs(PyTypeObject *type, PyObject *args, PyObject *kwds) {
+    GlobalSession *self;
+    static const char* kw[] = {"enable_glsl_input", NULL};
+    int enable_glsl_input = 0;
+    if (args && !PyArg_ParseTupleAndKeywords(args, kwds, "|p", kw, &enable_glsl_input)) return NULL;
+    self = (GlobalSession *)type->tp_alloc(type, 0);
+    ScopedPyObject ans((PyObject*)self);
+    if (self != NULL) {
+        self->ptr = nullptr;
+        SlangGlobalSessionDesc desc = {.enableGLSL=static_cast<bool>(enable_glsl_input)};
+        SlangResult result = createGlobalSession(&desc, self->ptr.writeRef());
+        if (SLANG_FAILED(result)) {
+            set_python_error(result, "failed to create slang global session");
+            ans.reset();
+        }
+    }
+    return ans.release();
+}
+
+static void
+dealloc_gs(GlobalSession* self) {
+    self->ptr = nullptr;
+    Py_TYPE(self)->tp_free((PyObject*)self);
+}
+
+static PyMethodDef gs_methods[] = {
+    {NULL}  /* Sentinel */
+};
+
+
+PyTypeObject GlobalSession_Type = {
+    PyVarObject_HEAD_INIT(NULL, 0)
+};
+
 static char doc[] = "Compile shaders";
 static PyMethodDef methods[] = {
     {NULL}  /* Sentinel */
 };
 
 static int
-exec_module(PyObject *mod) { (void)mod; return 0; }
+exec_module(PyObject *mod) {
+    Error = PyErr_NewException("slangc.Error", NULL, NULL);
+    if (Error == nullptr) return -1;
+    GlobalSession_Type.tp_name = "slangc.GlobalSession";
+    GlobalSession_Type.tp_basicsize = sizeof(GlobalSession);
+    GlobalSession_Type.tp_dealloc = (destructor)dealloc_gs;
+    GlobalSession_Type.tp_flags = Py_TPFLAGS_DEFAULT;
+    GlobalSession_Type.tp_doc = "GlobalSession";
+    GlobalSession_Type.tp_methods = gs_methods;
+    GlobalSession_Type.tp_new = new_gs;
+    if (PyType_Ready(&GlobalSession_Type) < 0) { return -1; }
+    if (PyModule_AddObject(mod, "GlobalSession", (PyObject *)&GlobalSession_Type) != 0) return -1;
+    Py_INCREF(&GlobalSession_Type);
+    if (PyModule_AddObject(mod, "Error", Error) < 0) { return -1; }
+    Py_INCREF(Error);
+    return 0;
+}
 
 static PyModuleDef_Slot slots[] = { {Py_mod_exec, (void*)exec_module}, {0, NULL} };
 
 static struct PyModuleDef module_def = {PyModuleDef_HEAD_INIT};
 
-PyObject*
+PyMODINIT_FUNC
 PyInit_slangc(void) {
 	module_def.m_name = "slangc";
 	module_def.m_slots = slots;
diff --git a/kitty/slangc.pyi b/kitty/slangc.pyi
new file mode 100644
index 000000000..d74f7d964
--- /dev/null
+++ b/kitty/slangc.pyi
@@ -0,0 +1,6 @@
+class Error(Exception):
+    pass
+
+
+class GlobalSession:
+    def __init__(self, enable_glsl_input: bool = False): ...