From: Lucas C.S. Subject: [PATCH] components/qr_code_generator: restore the cxx fallback M157 deleted the `cxx` path of the QR code generator (the `qr_code_generator_ffi_glue` crate, its buildflag header and the `#else` branch in qr_code_generator.cc), on the assumption the TODO in M156's BUILD.gn spelled out: that `enable_cpp_api_from_rust` is forever true. It is not with a system Rust: //build/config/rust.gni turns it off whenever `rust_sysroot_absolute` is set, Crubit's support library lives only in Google's bundled toolchain, and `gn gen` dies: ERROR at //build/rust/crubit/BUILD.gn:11:5: Unable to load ".../third_party/rust-toolchain/lib/third_party/crubit/support/BUILD.gn". and, past that, on the never-defined //third_party/rust/qr_code/v2:cpp_api_from_rust. This is a straight revert of the three files to M156.0.8078.79: the Crubit path is still taken whenever `enable_cpp_api_from_rust` is true (USE=bundled-toolchain), and the glue's dependencies -- qr_code/v2:lib and base/containers/span_rust.h -- are unchanged in M157. Drop it once upstream gates qr_code_generator again or ships Crubit's support library outside the toolchain. diff -ruN a/components/qr_code_generator/BUILD.gn b/components/qr_code_generator/BUILD.gn --- a/components/qr_code_generator/BUILD.gn +++ b/components/qr_code_generator/BUILD.gn @@ -2,6 +2,8 @@ # Use of this source code is governed by a BSD-style license that can be # found in the LICENSE file. +import("//build/buildflag_header.gni") +import("//build/config/rust.gni") import("//testing/libfuzzer/fuzzer_test.gni") declare_args() { @@ -9,8 +11,9 @@ enable_qr_print = false } +# Error type shared between C++ and Rust. source_set("error") { - public = [ "error.h" ] + sources = [ "error.h" ] } source_set("bitmap_generator") { @@ -30,23 +33,51 @@ ] } +# TODO(https://crbug.com/533546009): After Crubit bakes and sticks on the +# Stable release channel, then it should be okay to assume that +# `enable_cpp_api_from_rust` will be forever true (and remove +# `cxx::bridge`-related bits of QR code generator in this `BUILD.gn` file, bits +# in `.cc` files, and the whole `qr_code_generator_ffi_glue.rs` file). +buildflag_header("cpp_api_from_rust_buildflags") { + header = "cpp_api_from_rust_buildflags.h" + flags = [ "ENABLE_CPP_API_FROM_RUST=$enable_cpp_api_from_rust" ] + visibility = [ ":qr_code_generator" ] +} + source_set("qr_code_generator") { - # Enforces that `qr_code_generator.h` does not #include headers from private - # `deps`, which also stops GN from forwarding the Crubit bindings' hard_deps - # to targets depending on `:qr_code_generator`. - check_includes_strict = true - public = [ "qr_code_generator.h" ] - sources = [ "qr_code_generator.cc" ] - deps = [ - "//build/rust/crubit", - "//third_party/rust/qr_code/v2:cpp_api_from_rust", + sources = [ + "qr_code_generator.cc", + "qr_code_generator.h", ] + deps = [ ":cpp_api_from_rust_buildflags" ] + if (enable_cpp_api_from_rust) { + deps += [ + "//build/rust/crubit", + "//third_party/rust/qr_code/v2:cpp_api_from_rust", + ] + } else { + deps += [ ":qr_code_generator_ffi_glue" ] + } public_deps = [ ":error", "//base", ] } +if (!enable_cpp_api_from_rust) { + rust_static_library("qr_code_generator_ffi_glue") { + allow_unsafe = true # Needed for FFI that underpins the `cxx` crate. + crate_root = "qr_code_generator_ffi_glue.rs" + sources = [ "qr_code_generator_ffi_glue.rs" ] + cxx_bindings = [ "qr_code_generator_ffi_glue.rs" ] + visibility = [ ":qr_code_generator" ] + deps = [ + ":error", + "//third_party/rust/qr_code/v2:lib", + ] + } +} + source_set("unit_tests") { testonly = true sources = [ diff -ruN a/components/qr_code_generator/qr_code_generator.cc b/components/qr_code_generator/qr_code_generator.cc --- a/components/qr_code_generator/qr_code_generator.cc +++ b/components/qr_code_generator/qr_code_generator.cc @@ -10,10 +10,17 @@ #include "base/check.h" #include "base/check_op.h" +#include "base/containers/span_rust.h" #include "base/numerics/safe_conversions.h" +#include "components/qr_code_generator/cpp_api_from_rust_buildflags.h" + +#if BUILDFLAG(ENABLE_CPP_API_FROM_RUST) #include "third_party/crubit/support/rs_std/iterator_adapter.h" #include "third_party/crubit/support/rs_std/slice_ref.h" #include "third_party/rust/qr_code/v2/qr_code.h" +#else +#include "components/qr_code_generator/qr_code_generator_ffi_glue.rs.h" +#endif namespace qr_code_generator { @@ -22,6 +29,7 @@ GeneratedCode::GeneratedCode(GeneratedCode&&) = default; GeneratedCode& GeneratedCode::operator=(GeneratedCode&&) = default; +#if BUILDFLAG(ENABLE_CPP_API_FROM_RUST) Error RustErrorToCppError(const ::qr_code::types::QrError& rust_error) { if (rust_error == ::qr_code::types::QrError::MakeDataTooLong()) { return Error::kInputTooLong; @@ -63,5 +71,32 @@ CHECK_EQ(code.data.size(), static_cast(code.qr_size * code.qr_size)); return code; } +#else +base::expected GenerateCode( + base::span in, + std::optional min_version) { + rust::Slice rs_in = base::SpanToRustSlice(in); + + // `min_version` might come from a fuzzer and therefore we use a lenient + // `saturated_cast` instead of a `checked_cast`. + int16_t rs_min_version = + base::saturated_cast(min_version.value_or(0)); + + std::vector result_pixels; + size_t result_width = 0; + Error result_error = Error::kUnknownError; + bool result_is_success = generate_qr_code_using_rust( + rs_in, rs_min_version, result_pixels, result_width, result_error); + + if (!result_is_success) { + return base::unexpected(result_error); + } + GeneratedCode code; + code.data = std::move(result_pixels); + code.qr_size = base::checked_cast(result_width); + CHECK_EQ(code.data.size(), static_cast(code.qr_size * code.qr_size)); + return code; +} +#endif } // namespace qr_code_generator diff -ruN a/components/qr_code_generator/qr_code_generator_ffi_glue.rs b/components/qr_code_generator/qr_code_generator_ffi_glue.rs --- a/components/qr_code_generator/qr_code_generator_ffi_glue.rs +++ b/components/qr_code_generator/qr_code_generator_ffi_glue.rs @@ -0,0 +1,106 @@ +// Copyright 2023 The Chromium Authors +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. + +use cxx::CxxVector; +use qr_code::types::{Color, EcLevel, QrError}; +use qr_code::{QrCode, Version}; +use std::pin::Pin; + +#[cxx::bridge(namespace = "qr_code_generator")] +mod ffi { + #[repr(u8)] + enum Error { + kUnknownError = 0, + kInputTooLong = 1, + } + + extern "C++" { + include!("components/qr_code_generator/error.h"); + type Error; + } + + extern "Rust" { + fn generate_qr_code_using_rust( + data: &[u8], + min_version: i16, + out_pixels: Pin<&mut CxxVector>, + out_qr_size: &mut usize, + out_error: &mut Error, + ) -> bool; + } +} + +/// Translates `data` into a QR code. +/// +/// `min_version` can request a minimum QR code version. +fn generate(data: &[u8], min_version: Option) -> Result { + let mut qr_code = QrCode::new(data)?; + + let actual_version = match qr_code.version() { + Version::Micro(_) => panic!("QrCode::new should not generate micro QR codes"), + Version::Normal(actual_version) => actual_version, + }; + + match min_version { + None => (), + Some(min_version) if actual_version >= min_version => (), + Some(min_version) => { + // If `actual_version` < `min_version`, then re-encode using `min_version` + qr_code = QrCode::with_version(data, Version::Normal(min_version), EcLevel::M)?; + } + } + + Ok(qr_code) +} + +/// Translates `data` into a QR code. +/// +/// `min_version` can request a minimum QR code version (e.g. if the caller +/// requires that the QR code has a certain minimal width and height; for +/// example, QR code version 5 translates into 37x37 QR pixels). Setting +/// `min_version` to 0 means that the caller doesn't have any QR version +/// requirements. +/// +/// On success returns `true` and populates `out_pixels` and `out_qr_size`. On +/// failure returns `false` and populates `out_error`. +pub fn generate_qr_code_using_rust( + data: &[u8], + min_version: i16, + mut out_pixels: Pin<&mut CxxVector>, + out_qr_size: &mut usize, + out_error: &mut ffi::Error, +) -> bool { + let min_version = match min_version { + 0 => None, + 1..=40 => Some(min_version), + _ => { + *out_error = ffi::Error::kUnknownError; + return false; + } + }; + + match generate(data, min_version) { + Err(err) => { + *out_error = match err { + QrError::DataTooLong => ffi::Error::kInputTooLong, + _ => ffi::Error::kUnknownError, + }; + false + } + Ok(qr_code) => { + *out_qr_size = qr_code.width(); + + assert!(out_pixels.is_empty()); + for color in qr_code.into_colors() { + let u8_value = match color { + Color::Light => 0, + Color::Dark => 1, + }; + out_pixels.as_mut().push(u8_value); + } + + true + } + } +}