Merge branch 'more-constexpr-args' into 'master'

gi/arg-inl: Mark the arg functions as constexpr

See merge request GNOME/gjs!752

3 files changed, 46 insertions, 47 deletions

diff --git a/gi/arg-cache.cpp b/gi/arg-cache.cpp
index d5125fd7..ff0e59a2 100644
--- a/gi/arg-cache.cpp
+++ b/gi/arg-cache.cpp
@@ -6,6 +6,7 @@
 #include <config.h>
 
 #include <inttypes.h>
+#include <stddef.h>  // for size_t
 #include <stdint.h>
 #include <string.h>
 
@@ -61,34 +62,9 @@ static const char* expected_type_names[] = {"object", "function", "string"};
 static_assert(G_N_ELEMENTS(expected_type_names) == ExpectedType::LAST,
               "Names must match the values in ExpectedType");
 
-// A helper function to retrieve array lengths from a GIArgument (letting the
-// compiler generate good instructions in case of big endian machines)
-[[nodiscard]] size_t gjs_g_argument_get_array_length(GITypeTag tag,
-                                                     GIArgument* arg) {
-    switch (tag) {
-        case GI_TYPE_TAG_INT8:
-            return gjs_arg_get<int8_t>(arg);
-        case GI_TYPE_TAG_UINT8:
-            return gjs_arg_get<uint8_t>(arg);
-        case GI_TYPE_TAG_INT16:
-            return gjs_arg_get<int16_t>(arg);
-        case GI_TYPE_TAG_UINT16:
-            return gjs_arg_get<uint16_t>(arg);
-        case GI_TYPE_TAG_INT32:
-            return gjs_arg_get<int32_t>(arg);
-        case GI_TYPE_TAG_UINT32:
-            return gjs_arg_get<uint32_t>(arg);
-        case GI_TYPE_TAG_INT64:
-            return gjs_arg_get<int64_t>(arg);
-        case GI_TYPE_TAG_UINT64:
-            return gjs_arg_get<uint64_t>(arg);
-        default:
-            g_assert_not_reached();
-    }
-}
-
-static void gjs_g_argument_set_array_length(GITypeTag tag, GIArgument* arg,
-                                            size_t value) {
+static constexpr void gjs_g_argument_set_array_length(GITypeTag tag,
+                                                      GIArgument* arg,
+                                                      size_t value) {
     switch (tag) {
         case GI_TYPE_TAG_INT8:
             gjs_arg_set<int8_t>(arg, value);
@@ -208,7 +184,8 @@ struct Positioned {
         m_arg_pos = pos;
     }
 
-    bool set_out_parameter(GjsFunctionCallState* state, GIArgument* arg) {
+    constexpr bool set_out_parameter(GjsFunctionCallState* state,
+                                     GIArgument* arg) {
         gjs_arg_unset<void*>(&state->out_cvalue(m_arg_pos));
         gjs_arg_set(arg, &gjs_arg_member<void*>(&state->out_cvalue(m_arg_pos)));
         return true;
diff --git a/gi/arg-cache.h b/gi/arg-cache.h
index 2a02869b..ae73971d 100644
--- a/gi/arg-cache.h
+++ b/gi/arg-cache.h
@@ -8,7 +8,6 @@
 
 #include <config.h>
 
-#include <stddef.h>
 #include <stdint.h>
 
 #include <limits>
@@ -231,7 +230,4 @@ struct ArgsCache {
 
 }  // namespace Gjs
 
-[[nodiscard]] size_t gjs_g_argument_get_array_length(GITypeTag tag,
-                                                     GIArgument* arg);
-
 #endif  // GI_ARG_CACHE_H_
diff --git a/gi/arg-inl.h b/gi/arg-inl.h
index 5fb19e3b..5b2408e1 100644
--- a/gi/arg-inl.h
+++ b/gi/arg-inl.h
@@ -39,7 +39,7 @@
 //   appropriate union member for type T and returns the replaced value.
 
 template <auto GIArgument::*member>
-[[nodiscard]] inline decltype(auto) gjs_arg_member(GIArgument* arg) {
+[[nodiscard]] constexpr inline decltype(auto) gjs_arg_member(GIArgument* arg) {
     return (arg->*member);
 }
 
@@ -47,7 +47,7 @@ template <auto GIArgument::*member>
  * which are in fact typedef's of other generic types.
  * Setting a tag for a type allows to perform proper specialization. */
 template <typename T, GITypeTag TAG = GI_TYPE_TAG_VOID>
-[[nodiscard]] inline decltype(auto) gjs_arg_member(GIArgument* arg) {
+[[nodiscard]] constexpr inline decltype(auto) gjs_arg_member(GIArgument* arg) {
     if constexpr (TAG == GI_TYPE_TAG_VOID) {
         if constexpr (std::is_same_v<T, bool>)
             return gjs_arg_member<&GIArgument::v_boolean>(arg);
@@ -115,7 +115,7 @@ template <typename T, GITypeTag TAG = GI_TYPE_TAG_VOID>
 }
 
 template <typename T, GITypeTag TAG = GI_TYPE_TAG_VOID>
-inline void gjs_arg_set(GIArgument* arg, T v) {
+constexpr inline void gjs_arg_set(GIArgument* arg, T v) {
     if constexpr (std::is_pointer_v<T>) {
         using NonconstPtrT =
             std::add_pointer_t<std::remove_const_t<std::remove_pointer_t<T>>>;
@@ -132,18 +132,18 @@ inline void gjs_arg_set(GIArgument* arg, T v) {
 // Store function pointers as void*. It is a requirement of GLib that your
 // compiler can do this
 template <typename ReturnT, typename... Args>
-inline void gjs_arg_set(GIArgument* arg, ReturnT (*v)(Args...)) {
+constexpr inline void gjs_arg_set(GIArgument* arg, ReturnT (*v)(Args...)) {
     gjs_arg_member<void*>(arg) = reinterpret_cast<void*>(v);
 }
 
 template <typename T, GITypeTag TAG = GI_TYPE_TAG_VOID>
-inline std::enable_if_t<std::is_integral_v<T>> gjs_arg_set(GIArgument* arg,
-                                                           void *v) {
+constexpr inline std::enable_if_t<std::is_integral_v<T>> gjs_arg_set(
+    GIArgument* arg, void* v) {
     gjs_arg_set<T, TAG>(arg, gjs_pointer_to_int<T>(v));
 }
 
 template <typename T, GITypeTag TAG = GI_TYPE_TAG_VOID>
-[[nodiscard]] inline T gjs_arg_get(GIArgument* arg) {
+[[nodiscard]] constexpr inline T gjs_arg_get(GIArgument* arg) {
     if constexpr (std::is_same_v<T, bool> ||
                   (std::is_same_v<T, gboolean> && TAG == GI_TYPE_TAG_BOOLEAN))
         return T(!!gjs_arg_member<T, TAG>(arg));
@@ -152,12 +152,12 @@ template <typename T, GITypeTag TAG = GI_TYPE_TAG_VOID>
 }
 
 template <typename T, GITypeTag TAG = GI_TYPE_TAG_VOID>
-[[nodiscard]] inline void* gjs_arg_get_as_pointer(GIArgument* arg) {
+[[nodiscard]] constexpr inline void* gjs_arg_get_as_pointer(GIArgument* arg) {
     return gjs_int_to_pointer(gjs_arg_get<T, TAG>(arg));
 }
 
 template <typename T, GITypeTag TAG = GI_TYPE_TAG_VOID>
-inline void gjs_arg_unset(GIArgument* arg) {
+constexpr inline void gjs_arg_unset(GIArgument* arg) {
     if constexpr (std::is_pointer_v<T>)
         gjs_arg_set<T, TAG>(arg, nullptr);
     else
@@ -165,7 +165,7 @@ inline void gjs_arg_unset(GIArgument* arg) {
 }
 
 template <typename T, GITypeTag TAG = GI_TYPE_TAG_VOID>
-[[nodiscard]] inline T gjs_arg_steal(GIArgument* arg) {
+[[nodiscard]] constexpr inline T gjs_arg_steal(GIArgument* arg) {
     auto val = gjs_arg_get<T, TAG>(arg);
     gjs_arg_unset<T, TAG>(arg);
     return val;
@@ -174,10 +174,10 @@ template <typename T, GITypeTag TAG = GI_TYPE_TAG_VOID>
 // Implementation to store rounded (u)int64_t numbers into double
 
 template <typename BigT>
-[[nodiscard]] inline std::enable_if_t<std::is_integral_v<BigT> &&
-                                          (std::numeric_limits<BigT>::max() >
-                                           std::numeric_limits<int32_t>::max()),
-                                      double>
+[[nodiscard]] inline constexpr std::enable_if_t<
+    std::is_integral_v<BigT> && (std::numeric_limits<BigT>::max() >
+                                 std::numeric_limits<int32_t>::max()),
+    double>
 gjs_arg_get_maybe_rounded(GIArgument* arg) {
     BigT val = gjs_arg_get<BigT>(arg);
 
@@ -211,3 +211,29 @@ GJS_JSAPI_RETURN_CONVENTION inline bool gjs_arg_set_from_js_value(
 
     return true;
 }
+
+// A helper function to retrieve array lengths from a GIArgument (letting the
+// compiler generate good instructions in case of big endian machines)
+[[nodiscard]] constexpr size_t gjs_g_argument_get_array_length(
+    GITypeTag tag, GIArgument* arg) {
+    switch (tag) {
+        case GI_TYPE_TAG_INT8:
+            return gjs_arg_get<int8_t>(arg);
+        case GI_TYPE_TAG_UINT8:
+            return gjs_arg_get<uint8_t>(arg);
+        case GI_TYPE_TAG_INT16:
+            return gjs_arg_get<int16_t>(arg);
+        case GI_TYPE_TAG_UINT16:
+            return gjs_arg_get<uint16_t>(arg);
+        case GI_TYPE_TAG_INT32:
+            return gjs_arg_get<int32_t>(arg);
+        case GI_TYPE_TAG_UINT32:
+            return gjs_arg_get<uint32_t>(arg);
+        case GI_TYPE_TAG_INT64:
+            return gjs_arg_get<int64_t>(arg);
+        case GI_TYPE_TAG_UINT64:
+            return gjs_arg_get<uint64_t>(arg);
+        default:
+            g_assert_not_reached();
+    }
+}