[RFC PATCH 01/11] rust: qemu_api: do not disable lints outside bindgen-generated code

[Paolo Bonzini <pbonzini@redhat.com>]

rust/qemu-api/src/lib.rs is disabling lints that cause problems
with code generated by bindgen.  Instead, include the bindgen
code via include!(...) and move the #![allow()] directives
into the bindings module.

Add MESON_BUILD_ROOT to the devenv, so that it's easy for
build.rs to find the include file.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 meson.build                   |  4 +++-
 rust/qemu-api/.gitignore      |  2 +-
 rust/qemu-api/build.rs        | 20 ++++++++++++++------
 rust/qemu-api/meson.build     |  1 +
 rust/qemu-api/src/bindings.rs | 29 +++++++++++++++++++++++++++++
 rust/qemu-api/src/lib.rs      | 22 ----------------------
 6 files changed, 48 insertions(+), 30 deletions(-)
 create mode 100644 rust/qemu-api/src/bindings.rs

diff --git a/meson.build b/meson.build
index e0b880e4e13..a7342c6edbd 100644
--- 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'])
@@ -4089,7 +4091,7 @@ if have_rust
   bindings_rs = rust.bindgen(
     input: 'rust/wrapper.h',
     dependencies: common_ss.all_dependencies(),
-    output: 'bindings.rs',
+    output: 'bindings.rs.inc',
     include_directories: include_directories('.', 'include'),
     bindgen_version: ['>=0.60.0'],
     args: bindgen_args,
diff --git a/rust/qemu-api/.gitignore b/rust/qemu-api/.gitignore
index b9e7e004c86..2accb8745dc 100644
--- a/rust/qemu-api/.gitignore
+++ b/rust/qemu-api/.gitignore
@@ -1,2 +1,2 @@
 # Ignore generated bindings file overrides.
-src/bindings.rs
+/src/bindings.rs.inc
diff --git a/rust/qemu-api/build.rs b/rust/qemu-api/build.rs
index 20f8f718b90..e4eab718553 100644
--- a/rust/qemu-api/build.rs
+++ b/rust/qemu-api/build.rs
@@ -2,18 +2,26 @@
 // Author(s): Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
 // SPDX-License-Identifier: GPL-2.0-or-later
 
-use std::path::Path;
+use std::{env, 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."
-        );
+    // Placing bindings.rs.inc 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.rs.inc", path);
+    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."
+        ));
     }
 
+    println!("cargo:rustc-env=BINDINGS_RS_INC={}", file);
+
     // Check for available rustc features
     if rustc::is_min_version("1.77.0").unwrap_or(false) {
         println!("cargo:rustc-cfg=has_offset_of");
diff --git a/rust/qemu-api/meson.build b/rust/qemu-api/meson.build
index 6f637af7b1b..e3870e901e3 100644
--- 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
index 00000000000..1dac310594d
--- /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.rs.inc");
+
+#[cfg(not(MESON))]
+include!(env!("BINDINGS_RS_INC"));
+
+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 aa8d16ec94b..440aff3817d 100644
--- 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;
-- 
2.47.0