Bug 2064677 - Add MOZ_LIFETIME_CAPTURE_BY_THIS to fix -Wdeprecated-attributes with clang 23 r=sergesanspaille

clang 23 deprecates lifetime_capture_by(this) in favor of
lifetime_capture_by_this. Keep the old spelling as a fallback since the
minimum supported clang is still 19.

Differential Revision: https://phabricator.services.mozilla.com/D319738

mfbt/Attributes.h

@@ -486,6 +486,24 @@
 #  define MOZ_LIFETIME_CAPTURE_BY(x) /* nothing */
 #endif
 
+/**
+ * MOZ_LIFETIME_CAPTURE_BY_THIS is the equivalent of
+ * MOZ_LIFETIME_CAPTURE_BY(this). It needs to be spelled differently because
+ * clang 23 deprecated passing `this` to lifetime_capture_by in favor of the
+ * dedicated lifetime_capture_by_this attribute.
+ */
+#if defined(__clang__) && defined(__has_cpp_attribute)
+#  if __has_cpp_attribute(clang::lifetime_capture_by_this)
+#    define MOZ_LIFETIME_CAPTURE_BY_THIS [[clang::lifetime_capture_by_this]]
+#  elif __has_cpp_attribute(clang::lifetime_capture_by)
+#    define MOZ_LIFETIME_CAPTURE_BY_THIS [[clang::lifetime_capture_by(this)]]
+#  else
+#    define MOZ_LIFETIME_CAPTURE_BY_THIS /* nothing */
+#  endif
+#else
+#  define MOZ_LIFETIME_CAPTURE_BY_THIS /* nothing */
+#endif
+
 /**
  * MOZ_REINITIALIZES tells static analyser that a call to the associated
  * method leave it in an initialized state, typically after a std::move.

mfbt/api.yml

@@ -101,6 +101,7 @@ Attributes.h:
     - MOZ_GSL_POINTER
     - MOZ_LIFETIME_BOUND
     - MOZ_LIFETIME_CAPTURE_BY
+    - MOZ_LIFETIME_CAPTURE_BY_THIS
     - MOZ_STANDALONE_DEBUG
     - MOZ_NULL_AFTER_MOVE
     - MOZ_PUSH_DISABLE_NONTRIVIAL_UNION_WARNINGS

xpcom/string/nsTDependentString.h

@@ -103,12 +103,12 @@ class MOZ_GSL_POINTER nsTDependentString : public nsTString<T> {
    */
 
   using nsTString<T>::Rebind;
-  void Rebind(const char_type* aData MOZ_LIFETIME_CAPTURE_BY(this)) {
+  void Rebind(const char_type* aData MOZ_LIFETIME_CAPTURE_BY_THIS) {
     Rebind(aData, char_traits::length(aData));
   }
 
-  void Rebind(const char_type* aStart MOZ_LIFETIME_CAPTURE_BY(this),
-              const char_type* aEnd MOZ_LIFETIME_CAPTURE_BY(this));
+  void Rebind(const char_type* aStart MOZ_LIFETIME_CAPTURE_BY_THIS,
+              const char_type* aEnd MOZ_LIFETIME_CAPTURE_BY_THIS);
   void Rebind(const string_type&, index_type aStartPos);
 
  protected: