Revert "fix: C++ namespaces mangling"

This reverts commit 2deeabe.

Author: sehnryr

bindgen/codegen/mod.rs

@@ -786,7 +786,6 @@ impl CodeGenerator for Var {
                     &canonical_name,
                     link_name,
                     None,
-                    ctx.options().enable_cxx_namespaces,
                 ) {
                     canonical_name.as_str()
                 } else {
@@ -4658,7 +4657,6 @@ impl CodeGenerator for Function {
                 &canonical_name,
                 mangled_name,
                 Some(abi),
-                ctx.options().enable_cxx_namespaces,
             ))
             .then(|| mangled_name)
         });
@@ -5853,7 +5851,6 @@ pub(crate) mod utils {
         canonical_name: &str,
         mangled_name: &str,
         call_conv: Option<ClangAbi>,
-        enable_cxx_namespaces: bool,
     ) -> bool {
         // If the mangled name and the canonical name are the same then no
         // mangling can have happened between the two versions.
@@ -5862,28 +5859,29 @@ pub(crate) mod utils {
         }
 
         // Check if the mangled name is a valid C++ symbol
-        if let Ok(demangled) = ::cpp_demangle::Symbol::new(mangled_name) {
-            let demangled_name = match demangled.demangle(
-                &::cpp_demangle::DemangleOptions::default()
-                    .no_params()
-                    .no_return_type(),
-            ) {
-                Ok(name) => name,
-                Err(_) => demangled.to_string(),
-            };
+        if let Ok(demangled) = cpp_demangle::Symbol::new(mangled_name) {
+            let demangled_name = demangled.to_string().replace("::", "_");
 
-            // Either remove the namespace or replace "::" with "_" if cxx namespaces are enabled
-            let demangled_name = if enable_cxx_namespaces {
-                demangled_name
-                    .rsplit_once("::")
-                    .map(|(_, name)| name.to_string())
-                    .unwrap_or(demangled_name)
+            // Check that the demangled name is longer than the canonical name
+            if demangled_name.len() <= canonical_name.len() {
+                return false;
+            }
+
+            // Check that the demangled name starts with the canonical name
+            if !demangled_name.starts_with(canonical_name) {
+                return false;
+            }
+
+            // Check that the suffix is a signature
+            if let Some(suffix) = demangled_name.get(canonical_name.len()..) {
+                if !suffix.starts_with('(') || !suffix.ends_with(')') {
+                    return false;
+                }
             } else {
-                demangled_name.replace("::", "_")
-            };
+                return false;
+            }
 
-            // Now that we processed the demangled name, we can compare it with the canonical name
-            return canonical_name == demangled_name;
+            return true;
         }
 
         // Working with &[u8] makes indexing simpler than with &str