rust: allow using build-root bindings.rs from cargo

Right now, using cargo with QEMU requires copying by hand the bindings.rs to the
source tree.  Instead, we can use an include file to escape the cage of cargo's
mandated source directory structure.

By running cargo within meson's "devenv" and adding a MESON_BUILD_ROOT
environment variable, it is easy for build.rs to find the file.  However, the
file must be symlinked into cargo's output directory for rust-analyzer to find
it.

Suggested-by: Junjie Mao <junjie.mao@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/meson.build b/meson.build
index c35ce64cd61d690cc31c67c1c6e0bfd4062d8acd..ea211c2dbb491f841d77b83b9d2871edddd1c489 100644 (file)
--- a/meson.build
+++ b/meson.build
@@ -3,6 +3,8 @@ project('qemu', ['c'], meson_version: '>=1.5.0',
                           'b_staticpic=false', 'stdsplit=false', 'optimization=2', 'b_pie=true'],
         version: files('VERSION'))
 
+meson.add_devenv({ 'MESON_BUILD_ROOT' : meson.project_build_root() })
+
 add_test_setup('quick', exclude_suites: ['slow', 'thorough'], is_default: true)
 add_test_setup('slow', exclude_suites: ['thorough'], env: ['G_TEST_SLOW=1', 'SPEED=slow'])
 add_test_setup('thorough', env: ['G_TEST_SLOW=1', 'SPEED=thorough'])
@@ -4090,7 +4092,7 @@ if have_rust
   bindings_rs = rust.bindgen(
     input: 'rust/wrapper.h',
     dependencies: common_ss.all_dependencies(),
-    output: 'bindings.rs',
+    output: 'bindings.inc.rs',
     include_directories: include_directories('.', 'include'),
     bindgen_version: ['>=0.60.0'],
     args: bindgen_args,

diff --git a/rust/hw/char/pl011/.gitignore b/rust/hw/char/pl011/.gitignore
deleted file mode 100644 (file)
index 71eaff2..0000000
--- a/rust/hw/char/pl011/.gitignore
+++ /dev/null
@@ -1,2 +0,0 @@
-# Ignore generated bindings file overrides.
-src/bindings.rs.inc

diff --git a/rust/qemu-api/.gitignore b/rust/qemu-api/.gitignore
index b9e7e004c867bd1b5d44e69634d78fdafbfc1306..df6c2163e030a2aaf0e28b536c52be8ce44aaacb 100644 (file)
--- a/rust/qemu-api/.gitignore
+++ b/rust/qemu-api/.gitignore
@@ -1,2 +1,2 @@
 # Ignore generated bindings file overrides.
-src/bindings.rs
+/src/bindings.inc.rs

diff --git a/rust/qemu-api/README.md b/rust/qemu-api/README.md
index 7588fa29ef37e29d424fc7c333ea1c9c6139181b..53810f488828fd80c614586758061b7bc14990d3 100644 (file)
--- a/rust/qemu-api/README.md
+++ b/rust/qemu-api/README.md
@@ -5,7 +5,7 @@ This library exports helper Rust types, Rust macros and C FFI bindings for inter
 The C bindings can be generated with `bindgen`, using this build target:
 
 ```console
-$ ninja bindings.rs
+$ ninja bindings.inc.rs
 ```
 
 ## Generate Rust documentation
@@ -13,5 +13,5 @@ $ ninja bindings.rs
 To generate docs for this crate, including private items:
 
 ```sh
-cargo doc --no-deps --document-private-items
+pyvenv/bin/meson devenv -w ../rust cargo doc --no-deps --document-private-items
 ```

diff --git a/rust/qemu-api/build.rs b/rust/qemu-api/build.rs
index 20f8f718b90c0675e35db1922010516c736582b5..40644d5e4fe4f734619a40c90c14bb6c5636341e 100644 (file)
--- a/rust/qemu-api/build.rs
+++ b/rust/qemu-api/build.rs
@@ -2,17 +2,36 @@
 // Author(s): Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
 // SPDX-License-Identifier: GPL-2.0-or-later
 
-use std::path::Path;
+#[cfg(unix)]
+use std::os::unix::fs::symlink as symlink_file;
+#[cfg(windows)]
+use std::os::windows::fs::symlink_file;
+use std::{env, fs::remove_file, io::Result, path::Path};
 
 use version_check as rustc;
 
-fn main() {
-    if !Path::new("src/bindings.rs").exists() {
-        panic!(
-            "No generated C bindings found! Either build them manually with bindgen or with meson \
-             (`ninja bindings.rs`) and copy them to src/bindings.rs, or build through meson."
-        );
+fn main() -> Result<()> {
+    // Placing bindings.inc.rs in the source directory is supported
+    // but not documented or encouraged.
+    let path = env::var("MESON_BUILD_ROOT")
+        .unwrap_or_else(|_| format!("{}/src", env!("CARGO_MANIFEST_DIR")));
+
+    let file = format!("{}/bindings.inc.rs", path);
+    let file = Path::new(&file);
+    if !Path::new(&file).exists() {
+        panic!(concat!(
+            "No generated C bindings found! If you want to run `cargo`, start a subshell\n",
+            "with `meson devenv`, or point MESON_BUILD_ROOT to the top of the build tree."
+        ));
+    }
+
+    let out_dir = env::var("OUT_DIR").unwrap();
+    let dest_path = format!("{}/bindings.inc.rs", out_dir);
+    let dest_path = Path::new(&dest_path);
+    if dest_path.symlink_metadata().is_ok() {
+        remove_file(dest_path)?;
     }
+    symlink_file(file, dest_path)?;
 
     // Check for available rustc features
     if rustc::is_min_version("1.77.0").unwrap_or(false) {
@@ -20,4 +39,5 @@ fn main() {
     }
 
     println!("cargo:rerun-if-changed=build.rs");
+    Ok(())
 }

diff --git a/rust/qemu-api/meson.build b/rust/qemu-api/meson.build
index cad9ac4844e37287ae82c8094a78187fa75fdb47..3be7b7e5cede68e09db84464d237f30fbf3a87e0 100644 (file)
--- a/rust/qemu-api/meson.build
+++ b/rust/qemu-api/meson.build
@@ -9,6 +9,7 @@ _qemu_api_rs = static_library(
   structured_sources(
     [
       'src/lib.rs',
+      'src/bindings.rs',
       'src/c_str.rs',
       'src/definitions.rs',
       'src/device_class.rs',

diff --git a/rust/qemu-api/src/bindings.rs b/rust/qemu-api/src/bindings.rs
new file mode 100644 (file)
index 0000000..0b76ec5
--- /dev/null
+++ b/rust/qemu-api/src/bindings.rs
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#![allow(
+    dead_code,
+    improper_ctypes_definitions,
+    improper_ctypes,
+    non_camel_case_types,
+    non_snake_case,
+    non_upper_case_globals,
+    unsafe_op_in_unsafe_fn,
+    clippy::missing_const_for_fn,
+    clippy::too_many_arguments,
+    clippy::approx_constant,
+    clippy::use_self,
+    clippy::useless_transmute,
+    clippy::missing_safety_doc
+)]
+
+#[cfg(MESON)]
+include!("bindings.inc.rs");
+
+#[cfg(not(MESON))]
+include!(concat!(env!("OUT_DIR"), "/bindings.inc.rs"));
+
+unsafe impl Send for Property {}
+unsafe impl Sync for Property {}
+unsafe impl Sync for TypeInfo {}
+unsafe impl Sync for VMStateDescription {}
+unsafe impl Sync for VMStateField {}
+unsafe impl Sync for VMStateInfo {}

diff --git a/rust/qemu-api/src/lib.rs b/rust/qemu-api/src/lib.rs
index aa8d16ec94b30d7449e87931037936057d55a02e..440aff3817d3dbaafa552b3f93b317287dcf2685 100644 (file)
--- a/rust/qemu-api/src/lib.rs
+++ b/rust/qemu-api/src/lib.rs
@@ -4,31 +4,9 @@
 
 #![cfg_attr(not(MESON), doc = include_str!("../README.md"))]
 
-#[allow(
-    dead_code,
-    improper_ctypes_definitions,
-    improper_ctypes,
-    non_camel_case_types,
-    non_snake_case,
-    non_upper_case_globals,
-    unsafe_op_in_unsafe_fn,
-    clippy::missing_const_for_fn,
-    clippy::too_many_arguments,
-    clippy::approx_constant,
-    clippy::use_self,
-    clippy::useless_transmute,
-    clippy::missing_safety_doc,
-)]
 #[rustfmt::skip]
 pub mod bindings;
 
-unsafe impl Send for bindings::Property {}
-unsafe impl Sync for bindings::Property {}
-unsafe impl Sync for bindings::TypeInfo {}
-unsafe impl Sync for bindings::VMStateDescription {}
-unsafe impl Sync for bindings::VMStateField {}
-unsafe impl Sync for bindings::VMStateInfo {}
-
 pub mod c_str;
 pub mod definitions;
 pub mod device_class;