Automatic support for C-String literals

When `generate_cstr` is enabled, and the target rust version is >= 1.77, generate `c"..."` literals instead of the unsafe `from_bytes_with_nul_unchecked` calls.
rust-lang · Nov 29, 2024 · 66caf51 · 66caf51
1 parent d2e30fb
commit 66caf51
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Showing 5 changed files with 45 additions and 21 deletions.
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/bindgen-tests/tests/expectations/tests/strings_cstr2.rs b/bindgen-tests/tests/expectations/tests/strings_cstr2.rs
diff --git a/bindgen-tests/tests/headers/strings_cstr2.h b/bindgen-tests/tests/headers/strings_cstr2.h
@@ -0,0 +1,5 @@
+// bindgen-flags: --rust-target=1.77 --generate-cstr
+
+const char* MY_STRING_UTF8 = "Hello, world!";
+const char* MY_STRING_INTERIOR_NULL = "Hello,\0World!";
+const char* MY_STRING_NON_UTF8 = "ABCDE\xFF";
diff --git a/bindgen/codegen/mod.rs b/bindgen/codegen/mod.rs
@@ -717,26 +717,38 @@ impl CodeGenerator for Var {
                     let len = proc_macro2::Literal::usize_unsuffixed(
                         cstr_bytes.len(),
                     );
+                    let cstr =
+                        if options.generate_cstr && rust_features.const_cstr {
+                            CStr::from_bytes_with_nul(&cstr_bytes).ok()
+                        } else {
+                            None
+                        };
 
-                    // TODO: Here we ignore the type we just made up, probably
-                    // we should refactor how the variable type and ty ID work.
-                    let array_ty = quote! { [u8; #len] };
-                    let cstr_ty = quote! { ::#prefix::ffi::CStr };
-
-                    let bytes = proc_macro2::Literal::byte_string(&cstr_bytes);
-
-                    if options.generate_cstr &&
-                        rust_features.const_cstr &&
-                        CStr::from_bytes_with_nul(&cstr_bytes).is_ok()
-                    {
-                        result.push(quote! {
-                            #(#attrs)*
-                            #[allow(unsafe_code)]
-                            pub const #canonical_ident: &#cstr_ty = unsafe {
-                                #cstr_ty::from_bytes_with_nul_unchecked(#bytes)
-                            };
-                        });
+                    if let Some(cstr) = cstr {
+                        let cstr_ty = quote! { ::#prefix::ffi::CStr };
+                        if rust_features.literal_cstr {
+                            let cstr = proc_macro2::Literal::c_string(&cstr);
+                            result.push(quote! {
+                                #(#attrs)*
+                                pub const #canonical_ident: &#cstr_ty = #cstr;
+                            });
+                        } else {
+                            let bytes =
+                                proc_macro2::Literal::byte_string(&cstr_bytes);
+                            result.push(quote! {
+                                #(#attrs)*
+                                #[allow(unsafe_code)]
+                                pub const #canonical_ident: &#cstr_ty = unsafe {
+                                    #cstr_ty::from_bytes_with_nul_unchecked(#bytes)
+                                };
+                            });
+                        }
                     } else {
+                        // TODO: Here we ignore the type we just made up, probably
+                        // we should refactor how the variable type and ty ID work.
+                        let array_ty = quote! { [u8; #len] };
+                        let bytes =
+                            proc_macro2::Literal::byte_string(&cstr_bytes);
                         let lifetime =
                             if true { None } else { Some(quote! { 'static }) }
                                 .into_iter();

diff --git a/bindgen/features.rs b/bindgen/features.rs
@@ -159,7 +159,10 @@ define_rust_targets! {
         ptr_metadata: #81513,
         layout_for_ptr: #69835,
     },
-    Stable_1_77(77) => { offset_of: #106655 },
+    Stable_1_77(77) => {
+        offset_of: #106655,
+        literal_cstr: #117472,
+    },
     Stable_1_73(73) => { thiscall_abi: #42202 },
     Stable_1_71(71) => { c_unwind_abi: #106075 },
     Stable_1_68(68) => { abi_efiapi: #105795 },