mirror of
https://github.com/protocolbuffers/protobuf
synced 2026-08-26 02:23:14 -04:00
7fbb3d2cc7
The invariant is that PtrAndLen may hold ptr+len values which are legal for _either_ C++ string_view or Rust slices: constructing one from either Rust or C++ permits the laxest constraints, and care must be taken when converting a PtrAndLen into either type. For "into Rust slice" case to handle is that len=0 ptr must be non-null, so len=0 ptr=null gets turned into an arbitrary non-null pointer as provided by std::ptr::NonNull::dangling() (any preexisting non-null ptr is kept in that direction). For the "into C++ slice" the risk is more obscure that a Rust non-null pointer could potentially be an illegal pointer (such that ptr+0 is not a legal operation in C++), so when going into C++ we map any len=0 cases into ptr=null to avoid this as a possible risk. PiperOrigin-RevId: 704776210
51 lines
1.3 KiB
C++
51 lines
1.3 KiB
C++
#include "rust/cpp_kernel/strings.h"
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#include <cstring>
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#include <string>
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#include "absl/strings/string_view.h"
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#include "rust/cpp_kernel/rust_alloc_for_cpp_api.h"
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namespace google {
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namespace protobuf {
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namespace rust {
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std::string PtrAndLen::CopyToString() const {
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return len == 0 ? "" : std::string(ptr, len);
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}
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absl::string_view PtrAndLen::AsStringView() const {
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return absl::string_view(len == 0 ? nullptr : ptr, len);
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}
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void PtrAndLen::PlacementNewString(void* location) {
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new (location) std::string(len == 0 ? nullptr : ptr, len);
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}
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RustStringRawParts::RustStringRawParts(std::string src) {
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if (src.empty()) {
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data = nullptr;
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len = 0;
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} else {
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void* d = proto2_rust_alloc(src.length(), 1);
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std::memcpy(d, src.data(), src.length());
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data = static_cast<char*>(d);
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len = src.length();
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}
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}
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} // namespace rust
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} // namespace protobuf
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} // namespace google
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extern "C" {
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std::string* proto2_rust_cpp_new_string(google::protobuf::rust::PtrAndLen src) {
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return new std::string(src.CopyToString());
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}
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void proto2_rust_cpp_delete_string(std::string* str) { delete str; }
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google::protobuf::rust::PtrAndLen proto2_rust_cpp_string_to_view(std::string* str) {
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return google::protobuf::rust::PtrAndLen{str->data(), str->length()};
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}
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}
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