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move QML element registration to build.rs instead of bridge
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This avoids the need to repeatedly specify the URI and version
of the QML module in the bridges. QObjects that are registered as
QML elements are now marked by
[cxx_qt::qobject(qml_element = "OptionalName")]

This is a precursor to generating qmldir files which are required
for qmlcachegen and qmltc
(KDAB#242)
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@Be-ing
Be-ing committed Jul 25, 2023
1 parent e3013b1 commit 4199957
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Showing 22 changed files with 153 additions and 222 deletions.
153 changes: 82 additions & 71 deletions crates/cxx-qt-build/src/lib.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,7 @@ use diagnostics::{Diagnostic, GeneratedError};
use convert_case::{Case, Casing};
use quote::ToTokens;
use std::{
collections::{HashMap, HashSet},
collections::HashSet,
env,
fs::File,
io::Write,
Expand All @@ -26,7 +26,7 @@ use std::{

use cxx_qt_gen::{
parse_qt_file, write_cpp, write_rust, CppFragment, CxxQtItem, GeneratedCppBlocks,
GeneratedRustBlocks, Parser, QmlElementMetadata,
GeneratedRustBlocks, Parser,
};

// TODO: we need to eventually support having multiple modules defined in a single file. This
Expand All @@ -40,19 +40,25 @@ use cxx_qt_gen::{
struct GeneratedCppFilePaths {
plain_cpp: PathBuf,
qobject: Option<PathBuf>,
qobject_header: Option<QObjectHeader>,
}

struct QObjectHeader {
path: PathBuf,
qml_metadata: Vec<QmlElementMetadata>,
qobject_header: Option<PathBuf>,
}

struct GeneratedCpp {
cxx_qt: Option<CppFragment>,
cxx: cxx_gen::GeneratedCode,
file_ident: String,
qml_metadata: Vec<QmlElementMetadata>,
}

/// Metadata for registering a QML module
struct QmlModule {
/// The URI of the QML module
pub uri: String,
/// The minor version of the QML module
pub version_minor: usize,
/// The major version of the QML module
pub version_major: usize,
/// The .rs files with #[qml_element] attribute(s)
pub rust_files: Vec<PathBuf>,
}

impl GeneratedCpp {
Expand All @@ -67,7 +73,6 @@ impl GeneratedCpp {
.map_err(to_diagnostic)?;

let mut cxx_qt = None;
let mut qml_metadata = Vec::new();
// TODO: later change how the resultant filename is chosen, can we match the input file like
// CXX does?
//
Expand Down Expand Up @@ -120,11 +125,6 @@ impl GeneratedCpp {
.map_err(to_diagnostic)?;
let rust_tokens = write_rust(&generated_rust);
file_ident = parser.cxx_file_stem.clone();
for (_, qobject) in parser.cxx_qt_data.qobjects {
if let Some(q) = qobject.qml_metadata {
qml_metadata.push(q);
}
}

// We need to do this and can't rely on the macro, as we need to generate the
// CXX bridge Rust code that is then fed into the cxx_gen generation.
Expand All @@ -145,7 +145,6 @@ impl GeneratedCpp {
cxx_qt,
cxx,
file_ident,
qml_metadata,
})
}

Expand Down Expand Up @@ -183,10 +182,7 @@ impl GeneratedCpp {
header
.write_all(header_generated.as_bytes())
.expect("Could not write cxx-qt header file");
cpp_file_paths.qobject_header = Some(QObjectHeader {
path: header_path,
qml_metadata: self.qml_metadata,
});
cpp_file_paths.qobject_header = Some(header_path);

let cpp_path = PathBuf::from(format!(
"{}/{}.cxxqt.cpp",
Expand Down Expand Up @@ -232,7 +228,7 @@ impl GeneratedCpp {
fn generate_cxxqt_cpp_files(
rs_source: &[PathBuf],
header_dir: impl AsRef<Path>,
) -> Result<Vec<GeneratedCppFilePaths>, Diagnostic> {
) -> Vec<GeneratedCppFilePaths> {
let manifest_dir = env::var("CARGO_MANIFEST_DIR").unwrap();

let mut generated_file_paths: Vec<GeneratedCppFilePaths> = Vec::with_capacity(rs_source.len());
Expand All @@ -241,11 +237,17 @@ fn generate_cxxqt_cpp_files(
let path = format!("{manifest_dir}/{}", rs_path.display());
println!("cargo:rerun-if-changed={path}");

let generated_code = GeneratedCpp::new(&path)?;
let generated_code = match GeneratedCpp::new(&path) {
Ok(v) => v,
Err(diagnostic) => {
diagnostic.report();
std::process::exit(1);
}
};
generated_file_paths.push(generated_code.write_to_directories(cpp_directory, &header_dir));
}

Ok(generated_file_paths)
generated_file_paths
}

/// Run cxx-qt's C++ code generator on Rust modules marked with the `cxx_qt::bridge` macro, compile
Expand Down Expand Up @@ -283,9 +285,10 @@ fn generate_cxxqt_cpp_files(
#[derive(Default)]
pub struct CxxQtBuilder {
rust_sources: Vec<PathBuf>,
qobject_headers: Vec<QObjectHeader>,
qobject_headers: Vec<PathBuf>,
qrc_files: Vec<PathBuf>,
qt_modules: HashSet<String>,
qml_modules: Vec<QmlModule>,
cc_builder: cc::Build,
}

Expand All @@ -303,6 +306,7 @@ impl CxxQtBuilder {
qobject_headers: vec![],
qrc_files: vec![],
qt_modules,
qml_modules: vec![],
cc_builder: cc::Build::new(),
}
}
Expand Down Expand Up @@ -351,14 +355,31 @@ impl CxxQtBuilder {
self
}

/// Register a QML module at build time
pub fn qml_module(
mut self,
uri: &str,
version_major: usize,
version_minor: usize,
rust_files: &[impl AsRef<Path>],
) -> Self {
self.qml_modules.push(QmlModule {
uri: uri.to_owned(),
version_major,
version_minor,
rust_files: rust_files
.iter()
.map(|p| p.as_ref().to_path_buf())
.collect(),
});
self
}

/// Specify a C++ header containing a Q_OBJECT macro to run [moc](https://doc.qt.io/qt-6/moc.html) on.
/// This allows building QObject C++ subclasses besides the ones autogenerated by cxx-qt.
pub fn qobject_header(mut self, path: impl AsRef<Path>) -> Self {
let path = path.as_ref();
self.qobject_headers.push(QObjectHeader {
path: path.to_owned(),
qml_metadata: Vec::new(),
});
self.qobject_headers.push(path.to_owned());
println!("cargo:rerun-if-changed={}", path.display());
self
}
Expand Down Expand Up @@ -467,62 +488,52 @@ impl CxxQtBuilder {
}

// Generate files
match generate_cxxqt_cpp_files(&self.rust_sources, &generated_header_dir) {
Ok(generated_files) => {
for files in generated_files {
self.cc_builder.file(files.plain_cpp);
if let (Some(qobject), Some(qobject_header)) =
(files.qobject, files.qobject_header)
{
self.cc_builder.file(&qobject);
self.qobject_headers.push(qobject_header);
}
}
}
Err(diagnostic) => {
// When CXX-Qt fails in the build script, we shouldn't panic, as the Rust backtrace
// probably isn't useful. We can instead report the error nicely, using
// codespan_reporting and then just exit the build script with a non-zero exit code.
// This will make for a cleaner build-script output than panicing.
diagnostic.report();
std::process::exit(1);
for files in generate_cxxqt_cpp_files(&self.rust_sources, &generated_header_dir) {
self.cc_builder.file(files.plain_cpp);
if let (Some(qobject), Some(qobject_header)) = (files.qobject, files.qobject_header) {
self.cc_builder.file(&qobject);
self.qobject_headers.push(qobject_header);
}
}

// To support multiple QML elements with the same import URI, qmltyperegistrar must be run
// only once for each QML module (URI). So, collect the metadata for all QML elements within
// each module, regardless of which Rust QObject they are from.
let mut qml_modules = HashMap::<(String, usize, usize), Vec<PathBuf>>::new();
let mut cc_builder_whole_archive_files_added = false;
// Run moc on C++ headers with Q_OBJECT macro
for qobject_header in self.qobject_headers {
let uris = qobject_header
.qml_metadata
.iter()
.map(|qml_metadata| qml_metadata.uri.as_str());
let moc_products = qtbuild.moc(&qobject_header.path, uris);
let moc_products = qtbuild.moc(&qobject_header, None);
self.cc_builder.file(moc_products.cpp);
for qml_metadata in qobject_header.qml_metadata {
self.cc_builder.define("QT_STATICPLUGIN", None);
qml_modules
.entry((
qml_metadata.uri.clone(),
qml_metadata.version_major,
qml_metadata.version_minor,
))
.or_default()
.push(moc_products.metatypes_json.clone());
}
}
for ((uri, version_major, version_minor), paths) in qml_modules {
let qml_type_registration_files =
qtbuild.register_qml_types(&paths, version_major, version_minor, &uri);

let mut cc_builder_whole_archive_files_added = false;

// Bridges for QML modules are handled separately because
// the metatypes_json generated by moc needs to be passed to qmltyperegistrar
for qml_module in self.qml_modules {
let mut qml_metatypes_json = Vec::new();

for files in generate_cxxqt_cpp_files(&qml_module.rust_files, &generated_header_dir) {
self.cc_builder.file(files.plain_cpp);
if let (Some(qobject), Some(qobject_header)) = (files.qobject, files.qobject_header)
{
self.cc_builder.file(&qobject);
let moc_products = qtbuild.moc(qobject_header, Some(&qml_module.uri));
self.cc_builder.file(moc_products.cpp);
qml_metatypes_json.push(moc_products.metatypes_json);
}
}

let qml_type_registration_files = qtbuild.register_qml_types(
&qml_metatypes_json,
qml_module.version_major,
qml_module.version_minor,
&qml_module.uri,
);
self.cc_builder
.file(qml_type_registration_files.qmltyperegistrar);
self.cc_builder.file(qml_type_registration_files.plugin);
cc_builder_whole_archive.file(qml_type_registration_files.plugin_init);
self.cc_builder.define("QT_STATICPLUGIN", None);
cc_builder_whole_archive_files_added = true;
}

for qrc_file in self.qrc_files {
cc_builder_whole_archive.file(qtbuild.qrc(&qrc_file));
cc_builder_whole_archive_files_added = true;
Expand Down
6 changes: 3 additions & 3 deletions crates/cxx-qt-gen/src/generator/cpp/qobject.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -214,7 +214,7 @@ mod tests {
#[cxx_qt::bridge(namespace = "cxx_qt")]
mod ffi {
extern "RustQt" {
#[cxx_qt::qobject(qml_uri = "com.kdab", qml_version = "1.0", qml_name = "MyQmlElement")]
#[cxx_qt::qobject(qml_element = "MyQmlElement")]
type MyNamedObject = super::MyNamedObjectRust;
}
}
Expand All @@ -240,7 +240,7 @@ mod tests {
#[cxx_qt::bridge(namespace = "cxx_qt")]
mod ffi {
extern "RustQt" {
#[cxx_qt::qobject(qml_uri = "com.kdab", qml_version = "1.0", qml_singleton)]
#[cxx_qt::qobject(qml_element, qml_singleton)]
type MyObject = super::MyObjectRust;
}
}
Expand All @@ -267,7 +267,7 @@ mod tests {
#[cxx_qt::bridge(namespace = "cxx_qt")]
mod ffi {
extern "RustQt" {
#[cxx_qt::qobject(qml_uri = "com.kdab", qml_version = "1.0", qml_uncreatable)]
#[cxx_qt::qobject(qml_element, qml_uncreatable)]
type MyObject = super::MyObjectRust;
}
}
Expand Down
2 changes: 1 addition & 1 deletion crates/cxx-qt-gen/src/generator/rust/qobject.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -259,7 +259,7 @@ mod tests {
#[cxx_qt::bridge(namespace = "cxx_qt")]
mod ffi {
extern "RustQt" {
#[cxx_qt::qobject(qml_uri = "com.kdab", qml_version = "1.0", qml_singleton)]
#[cxx_qt::qobject(qml_element, qml_singleton)]
type MyObject = super::MyObjectRust;
}
}
Expand Down
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