1 // Protocol Buffers - Google's data interchange format 2 // Copyright 2024 Google LLC. All rights reserved. 3 // 4 // Use of this source code is governed by a BSD-style 5 // license that can be found in the LICENSE file or at 6 // https://developers.google.com/open-source/licenses/bsd 7 8 #ifndef GOOGLE_PROTOBUF_RUST_CPP_KERNEL_STRINGS_H__ 9 #define GOOGLE_PROTOBUF_RUST_CPP_KERNEL_STRINGS_H__ 10 11 #include <cstddef> 12 #include <cstring> 13 #include <string> 14 15 namespace google { 16 namespace protobuf { 17 namespace rust { 18 19 // Represents an ABI-stable version of &[u8]/string_view (borrowed slice of 20 // bytes) for FFI use only. 21 struct PtrAndLen { 22 /// Borrows the memory. 23 const char* ptr; 24 size_t len; 25 }; 26 27 // Represents an owned string for FFI purposes. 28 // 29 // This must only be used to transfer a string from C++ to Rust. The 30 // below invariants must hold: 31 // * Rust and C++ versions of this struct are ABI compatible. 32 // * The data were allocated using the Rust allocator and are 1 byte aligned. 33 // * The data is valid UTF-8. 34 struct RustStringRawParts { 35 // Owns the memory. 36 const char* data; 37 size_t len; 38 39 RustStringRawParts() = delete; 40 // Copies src. 41 explicit RustStringRawParts(std::string src); 42 }; 43 44 } // namespace rust 45 } // namespace protobuf 46 } // namespace google 47 48 extern "C" { 49 50 // Allocates a new std::string on the C++ heap and returns a pointer to it. 51 std::string* proto2_rust_cpp_new_string(google::protobuf::rust::PtrAndLen src); 52 53 // Deletes a std::string object from the C++ heap. 54 void proto2_rust_cpp_delete_string(std::string* str); 55 56 // Obtain a PtrAndLen, the FFI-safe view type, from a std::string. 57 google::protobuf::rust::PtrAndLen proto2_rust_cpp_string_to_view(std::string* str); 58 } 59 60 #endif // GOOGLE_PROTOBUF_RUST_CPP_KERNEL_STRINGS_H__ 61