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//! The `rsconf` crate contains `build.rs` helper utilities and funcitionality to assist with
//! managing complicated build scripts, interacting with the native/system headers and libraries,
//! exposing rust constants based off of system headers, and conditionally compiling rust code based
//! off the presence or absence of certain functionality in the system headers and libraries.
//!
//! This crate can be used standalone or in conjunction with the [`cc`
//! crate](https://docs.rs/cc/latest/cc/) when introspecting the build system's environment.
//!
//! In addition to facilitating easier ffi and other native system interop, `rsconf` also exposes a
//! strongly typed API for interacting with `cargo` at build-time and influencing its behavior,
//! including more user-friendly alternatives to the low-level `println!("cargo:xxx")` "api" used to
//! enable features, enable `#[cfg(...)]` conditional compilation blocks or define `cfg` values, and
//! more.
mod tempdir;
#[cfg(test)]
mod tests;
use cc::Build;
use std::borrow::Cow;
use std::ffi::{OsStr, OsString};
use std::io::prelude::*;
use std::path::PathBuf;
use std::process::{Command, Output};
use std::sync::atomic::{AtomicI32, Ordering};
use tempdir::TempDir;
static FILE_COUNTER: AtomicI32 = AtomicI32::new(0);
type BoxedError = Box<dyn std::error::Error + Send + Sync + 'static>;
/// Exposes an interface for testing whether the target system supports a particular feature or
/// provides certain functionality. This is the bulk of the `rsconf` api.
pub struct Target {
/// Whether or not we are compiling with `cl.exe` (and not `clang.exe`) under `xxx-pc-windows-msvc`.
is_cl: bool,
temp: TempDir,
toolchain: Build,
verbose: bool,
}
macro_rules! snippet {
($name:expr) => {
include_str!(concat!("../snippets/", $name))
};
}
/// An error encountered during the compliation stage.
///
/// This is currently not public because we only return it as [`BoxedError`].
#[derive(Debug)]
struct CompilationError {
output: Output,
}
impl std::fmt::Display for CompilationError {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.write_fmt(format_args!(
"Compilation error: {}",
String::from_utf8_lossy(&self.output.stderr)
))
}
}
impl std::error::Error for CompilationError {}
fn output_or_err(output: Output) -> Result<(String, String), BoxedError> {
if output.status.success() {
Ok((
String::from_utf8(output.stdout)?,
String::from_utf8(output.stderr)?,
))
} else {
Err(Box::new(CompilationError { output }))
}
}
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
enum BuildMode {
Executable,
ObjectFile,
}
/// Specifies how a dependency library is linked.
#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
pub enum LinkType {
/// Cargo is instructed to link the library without specifying/overriding how linking is
/// performed. If an environment variable `LIBNAME_STATIC` is present, the dependency will be
/// statically linked. (This way, downstream consumers of the crate may influence how the
/// dependency is linked without modifying the build script and/or features.)
///
/// Cargo is instructed to automatically rerun the build script if an environment variable by
/// this name exists; you do not have to call [`rebuild_if_env_changed()`] yourself.
#[default]
Default,
/// Cargo will be instructed to explicitly dynamically link against the target library,
/// overriding the default configuration specified by the configuration or the toolchain.
Dynamic,
/// Cargo will be instructed to explicitly statically link against the target library,
/// overriding the default configuration specified by the configuration or the toolchain.
Static,
}
impl LinkType {
fn emit_link_line(&self, lib: &str) {
match self {
LinkType::Static => println!("cargo:rustc-link-lib=static={lib}"),
LinkType::Dynamic => println!("cargo:rustc-link-lib=dylib={lib}"),
LinkType::Default => {
// We do not specify the build type unless the LIBNAME_STATIC environment variable
// is defined (and not set to 0), in which was we emit a static linkage instruction.
let name = format!("{}_STATIC", lib.to_ascii_uppercase());
println!("cargo:rerun-if-env-changed={name}");
match std::env::var(name).as_deref() {
Err(_) | Ok("0") => println!("cargo:rustc-link-lib={lib}"),
_ => LinkType::Static.emit_link_line(lib),
}
}
}
}
}
/// Instruct Cargo to link the target object against `library`.
pub fn link_library(library: &str, how: LinkType) {
how.emit_link_line(library)
}
/// Instruct Cargo to link the target object against `libraries` in the order provided.
pub fn link_libraries(libraries: &[&str], how: LinkType) {
for lib in libraries {
how.emit_link_line(lib)
}
}
/// Instruct Cargo to rerun the build script if the provided path changes.
///
/// Change detection is based off the modification time (mtime). If the path is to a directory, the
/// build script is re-run if any files under that directory are modified.
///
/// By default, Cargo reruns the build script if any file in the source tree is modified. To make it
/// ignore changes, specify a file. To make it ignore all changes, call this with `"build.rs"` as
/// the target.
pub fn rebuild_if_path_changed(path: &str) {
println!("cargo:rerun-if-changed={path}");
}
/// Instruct Cargo to rerun the build script if any of the provided paths change.
///
/// See [`rebuild_if_path_changed()`] for more information.
pub fn rebuild_if_paths_changed(paths: &[&str]) {
for path in paths {
rebuild_if_path_changed(path)
}
}
/// Instruct Cargo to rerun the build script if the named environment variable changes.
pub fn rebuild_if_env_changed(var: &str) {
println!("cargo:rerun-if-env-changed={var}");
}
/// Instruct Cargo to rerun the build script if any of the named environment variables change.
pub fn rebuild_if_envs_changed(vars: &[&str]) {
for var in vars {
rebuild_if_env_changed(var);
}
}
/// Emit a compile-time warning.
///
/// This is typically only shown for the current crate when building with `cargo build`, but
/// warnings for non-path dependencies can be shown by using `cargo build -vv`.
#[macro_export]
macro_rules! warn {
($msg:tt $(, $($arg:tt)*)?) => {{
println!(concat!("cargo:warning=", $msg) $(, $($arg)*)?)
}};
}
/// Enables a feature flag that compiles code annotated with `#[cfg(feature = "name")]`.
///
/// The feature does not have to be named in `Cargo.toml` to be used here or in your code, but any
/// features dynamically enabled via this script will not participate in dependency resolution.
///
/// As of rust 1.80, features enabled in `build.rs` but not declared in `Cargo.toml` might trigger
/// build-time warnings; use [`declare_feature()`] instead to avoid this warning.
pub fn enable_feature(name: &str) {
declare_feature(name, true)
}
/// Informs the compiler of a `feature` with the name `name`, possibly enabled.
///
/// The feature does not have to be named in `Cargo.toml` to be used here or in your code, but any
/// features dynamically enabled via this script will not participate in dependency resolution.
pub fn declare_feature(name: &str, enabled: bool) {
if name.chars().any(|c| c == '"') {
panic!("Invalid feature name: {name}");
}
declare_cfg_values("feature", &[name]);
if enabled {
println!("cargo:rustc-cfg=feature=\"{name}\"");
}
}
/// Informs the compiler of a `cfg` with the name `name`, possibly enabled.
///
/// Enables conditional compilation of code behind `#[cfg(name)]` or with `if cfg!(name)`
/// (without quotes around `name`).
///
/// As of rust 1.80, using `#[cfg(foo)]` when said feature is not enabled results in a
/// compile-time warning as rust tries to protect against inadvertent use of invalid/unknown
/// features. Unlike [`enable_cfg()`], this function informs `rustc` about the presence of a feature
/// called `name` even when it's not enabled, so that `#[cfg(foo)]` or `#[cfg(not(foo))] do not
/// cause warnings when the `foo` cfg is not enabled.
///
/// See also: [`declare_cfg_values()`].
pub fn declare_cfg(name: &str, enabled: bool) {
if name.chars().any(|c| !c.is_ascii_alphanumeric() && c != '_') {
panic!("Invalid cfg name {name}");
}
// Use #[cfg(version = "1.80.0")] when RFC 2523 finally lands
if rustc_version()
.map(|v| !v.cmp(&(1, 80, 0)).is_lt())
.unwrap_or(true)
{
println!("cargo:rustc-check-cfg=cfg({name})");
}
if enabled {
println!("cargo:rustc-cfg={name}");
}
}
/// Enables Cargo/rustc feature with the name `name`.
///
/// Allows conditional compilation of code behind `#[cfg(name)]` or with `if cfg!(name)` (without
/// quotes around `name`).
///
/// See [`set_cfg_value()`] to set a `(name, value)` tuple to enable conditional compilation of the
/// form `#[cfg(name = "value")]` for cases where `name` is not a boolean cfg but rather takes any
/// of several discrete values.
///
/// Note the different from `#[cfg(feature = "name")]`! The configuration is invisible to end users
/// of your code (i.e. `name` does not appear anywhere in `Cargo.toml`) and does not participate in
/// dependency resolution.
pub fn enable_cfg(name: &str) {
declare_cfg(name, true);
}
// TODO: Add a builder method to encompass the functionality of declare_cfg()/set_cfg()/
// declare_cfg_values()/set_cfg_value(). Something like
// add_cfg("name").with_values(["a", "b", "c"])
// followed by .enable() or .set_value("a")
/// Inform the compiler of a cfg with name `name` and all its known valid values.
///
/// Call this before calling [`set_cfg_value()`] to avoid compiler warnings about unrecognized cfg
/// values under rust 1.80+.
pub fn declare_cfg_values(name: &str, values: &[&str]) {
if name.chars().any(|c| !c.is_ascii_alphanumeric() && c != '_') {
panic!("Invalid cfg name {name}");
}
// Use #[cfg(version = "1.80.0")] when RFC 2523 finally lands
if rustc_version()
.map(|v| !v.cmp(&(1, 80, 0)).is_lt())
.unwrap_or(true)
{
let payload = values
.iter()
.inspect(|value| {
if value.chars().any(|c| c == '"') {
panic!("Invalid value {value} for cfg {name}");
}
})
.map(|v| format!("\"{v}\""))
.collect::<Vec<_>>()
.join(",");
println!("cargo:rustc-check-cfg=cfg({name}, values({payload}))");
}
}
/// Activates conditional compilation for code behind `#[cfg(name = "value")]` or with `if cfg!(name
/// = "value")`.
///
/// As with [`enable_cfg()`], this is entirely internal to your code: `name` should not appear in
/// `Cargo.toml` and this configuration does not participate in dependency resolution (which takes
/// place before your build script is called).
///
/// Call [`declare_cfg_values()`] beforehand to inform the compiler of all possible values for this
/// cfg or else rustc 1.80+ will issue a compile-time warning about unrecognized cfg values.
pub fn set_cfg_value(name: &str, value: &str) {
if value.chars().any(|c| c == '"') {
panic!("Invalid value {value} for cfg {name}");
}
println!("cargo:rustc-cfg={name}={value}\"");
}
/// Makes an environment variable available to your code at build time, letting you use the value as
/// a compile-time constant with `env!(NAME)`.
pub fn set_env_value(name: &str, value: &str) {
if value.chars().any(|c| c == '"') {
panic!("Invalid value {value} for env var {name}");
}
println!("cargo:rustc-env={name}={value}");
}
/// Add a path to the list of directories rust will search when attempting to find a library to link
/// against.
///
/// The path does not have to exist as it could be created by the build script at a later date or
/// could be targeting a different platform altogether.
pub fn add_library_search_path(dir: &str) {
println!("cargo:rustc-link-search={dir}");
}
impl Target {
const NONE: &'static [&'static str] = &[];
#[inline(always)]
#[allow(non_snake_case)]
fn NULL_CB(_: &str, _: &str) {}
/// Create a new rsconf instance using the default [`cc::Build`] toolchain for the current
/// compilation target.
///
/// Use [`Target::new_from()`] to use a configured [`cc::Build`] instance instead.
pub fn new() -> std::io::Result<Target> {
let toolchain = cc::Build::new();
Target::new_from(toolchain)
}
/// Create a new rsconf instance from the configured [`cc::Build`] instance `toolchain`.
///
/// All tests inherit their base configuration from `toolchain`, so make sure it is configured
/// with the appropriate header and library search paths as needed.
pub fn new_from(mut toolchain: cc::Build) -> std::io::Result<Target> {
let temp = if let Some(out_dir) = std::env::var_os("OUT_DIR") {
TempDir::new_in(out_dir)?
} else {
// Configure Build's OUT_DIR if not set (e.g. for testing)
let temp = TempDir::new()?;
toolchain.out_dir(&temp);
temp
};
let is_cl = cfg!(windows) && toolchain.get_compiler().is_like_msvc();
Ok(Self {
is_cl,
temp,
toolchain,
verbose: false,
})
}
/// Enables or disables verbose mode.
///
/// In verbose mode, output of rsconf calls to the compiler are displayed to stdout and stderr.
/// It is not enabled by default.
///
/// Note that `cargo` suppresses all `build.rs` output in case of successful execution by
/// default; intentionally fail the build (e.g. add a `panic!()` call) or compile with `cargo
/// build -vv` to see verbose output.
pub fn set_verbose(&mut self, verbose: bool) {
self.verbose = verbose;
}
fn new_temp<S: AsRef<str>>(&self, stub: S, ext: &str) -> PathBuf {
let file_num = FILE_COUNTER.fetch_add(1, Ordering::Release);
let stub = stub.as_ref();
let mut path = self.temp.to_owned();
path.push(format!("{stub}-test-{file_num}{ext}"));
path
}
fn build<S: AsRef<str>, C>(
&self,
stub: &str,
mode: BuildMode,
code: &str,
libraries: &[S],
callback: C,
) -> Result<PathBuf, BoxedError>
where
C: FnOnce(&str, &str),
{
let stub = fs_sanitize(stub);
let in_path = self.new_temp(&stub, ".c");
std::fs::File::create(&in_path)?.write_all(code.as_bytes())?;
let exe_ext = if cfg!(unix) { ".out" } else { ".exe" };
let obj_ext = if cfg!(unix) { ".o" } else { ".obj" };
let out_path = match mode {
BuildMode::Executable => self.new_temp(&stub, exe_ext),
BuildMode::ObjectFile => self.new_temp(&stub, obj_ext),
};
let mut cmd = self.toolchain.try_get_compiler()?.to_command();
cmd.current_dir(&self.temp);
let exe = mode == BuildMode::Executable;
let link = exe || !libraries.is_empty();
let output = if cfg!(unix) || !self.is_cl {
cmd.args([in_path.as_os_str(), OsStr::new("-o"), out_path.as_os_str()]);
if !link {
cmd.arg("-c");
} else if !libraries.is_empty() {
for library in libraries {
cmd.arg(format!("-l{}", library.as_ref()));
}
}
cmd
} else {
cmd.arg(in_path);
let mut output = OsString::from(if exe { "/Fe:" } else { "/Fo:" });
output.push(&out_path);
cmd.arg(output);
if !link {
cmd.arg("/c");
} else if !libraries.is_empty() {
cmd.arg("/link");
for library in libraries {
let mut library = Cow::from(library.as_ref());
if !library.contains('.') {
let owned = library + ".lib";
library = owned;
}
cmd.arg(library.as_ref());
}
}
cmd
}
.output()?;
// We want to output text in verbose mode but writing directly to stdout doesn't get
// intercepted by the cargo test harness. In test mode, we use the slower `println!()`/
// `eprintln!()` macros together w/ from_utf8_lossy() to suppress unnecessary output when
// we're not investigating the details with `cargo test -- --nocapture`, but we use the
// faster approach when we're being used in an actual build script.
#[cfg(test)]
if self.verbose {
println!("{}", String::from_utf8_lossy(&output.stdout));
eprintln!("{}", String::from_utf8_lossy(&output.stderr));
}
#[cfg(not(test))]
if self.verbose {
std::io::stdout().lock().write_all(&output.stdout).ok();
std::io::stderr().lock().write_all(&output.stderr).ok();
}
// Handle custom `CompilationError` output if we failed to compile.
let output = output_or_err(output)?;
callback(&output.0, &output.1);
// Return the path to the resulting exe
assert!(out_path.exists());
Ok(out_path)
}
/// Checks whether a definition for type `name` exists without pulling in any headers.
///
/// This operation does not link the output; only the header file is inspected.
pub fn has_type(&self, name: &str) -> bool {
let snippet = format!(snippet!("has_type.c"), "", name);
self.build(
name,
BuildMode::ObjectFile,
&snippet,
Self::NONE,
Self::NULL_CB,
)
.is_ok()
}
/// Checks whether a definition for type `name` exists in the supplied header or headers.
///
/// The `headers` are included in the order they are provided for testing. See
/// [`has_type()`](Self::has_type) for more info.
pub fn has_type_in(&self, name: &str, headers: &[&str]) -> bool {
let stub = format!("{}_multi", headers.first().unwrap_or(&"has_type_in"));
let snippet = format!(snippet!("has_type.c"), to_includes(headers), name);
self.build(
&stub,
BuildMode::ObjectFile,
&snippet,
Self::NONE,
Self::NULL_CB,
)
.is_ok()
}
/// Checks whether or not the the requested `symbol` is exported by libc/by default (without
/// linking against any additional libraries).
///
/// See [`has_symbol_in()`](Self::has_symbol_in) to link against one or more libraries and test.
///
/// This only checks for symbols exported by the C abi (so mangled names are required) and does
/// not check for compile-time definitions provided by header files.
///
/// See [`has_type()`](Self::has_type) to check for compile-time definitions. This
/// function will return false if `library` could not be found or could not be linked; see
/// [`has_library()`](Self::has_library) to test if `library` can be linked separately.
pub fn has_symbol(&self, symbol: &str) -> bool {
let snippet = format!(snippet!("has_symbol.c"), symbol);
let libs: &'static [&'static str] = &[];
self.build(symbol, BuildMode::Executable, &snippet, libs, Self::NULL_CB)
.is_ok()
}
/// Like [`has_symbol()`] but links against a library or any number of `libraries`.
///
/// You might need to supply multiple libraries if `symbol` is in a library that has its own
/// transitive dependencies that must also be linked for compilation to succeed. Note that
/// libraries are linked in the order they are provided.
///
/// [`has_symbol()`]: Self::has_symbol()
pub fn has_symbol_in(&self, symbol: &str, libraries: &[&str]) -> bool {
let snippet = format!(snippet!("has_symbol.c"), symbol);
self.build(
symbol,
BuildMode::Executable,
&snippet,
libraries,
Self::NULL_CB,
)
.is_ok()
}
/// Checks for the presence of all the named symbols in the libraries provided.
///
/// Libraries are linked in the order provided. See [`has_symbol()`] and [`has_symbol_in()`] for
/// more information.
///
/// [`has_symbol()`]: Self::has_symbol()
/// [`has_symbol_in()`]: Self::has_symbol_in()
pub fn has_symbols_in(&self, symbols: &[&str], libraries: &[&str]) -> bool {
symbols
.iter()
.copied()
.all(|symbol| self.has_symbol_in(symbol, libraries))
}
/// Tests whether or not it was possible to link against `library`.
///
/// If it is not possible to link against `library` without also linking against its transitive
/// dependencies, use [`has_libraries()`](Self::has_libraries) to link against multiple
/// libraries (in the order provided).
///
/// You should normally pass the name of the library without any prefixes or suffixes. If a
/// suffix is provided, it will not be removed.
///
/// You may pass a full path to the library (again minus the extension) instead of just the
/// library name in order to try linking against a library not in the library search path.
/// Alternatively, configure the [`cc::Build`] instance with the search paths as needed before
/// passing it to [`Target::new()`].
///
/// Under Windows, if `library` does not have an extension it will be suffixed with `.lib` prior
/// to testing linking. (This way it works under under both `cl.exe` and `clang.exe`.)
pub fn has_library(&self, library: &str) -> bool {
let snippet = snippet!("empty.c");
self.build(
library,
BuildMode::ObjectFile,
snippet,
&[library],
Self::NULL_CB,
)
.is_ok()
}
/// Tests whether or not it was possible to link against all of `libraries`.
///
/// See [`has_library()`](Self::has_library()) for more information.
///
/// The libraries will be linked in the order they are provided in when testing, which may
/// influence the outcome.
pub fn has_libraries(&self, libraries: &[&str]) -> bool {
let stub = libraries.first().copied().unwrap_or("has_libraries");
let snippet = snippet!("empty.c");
self.build(
stub,
BuildMode::ObjectFile,
snippet,
libraries,
Self::NULL_CB,
)
.is_ok()
}
/// Returns the first library from those provided that can be successfully linked.
///
/// Returns a reference to the first library name that was passed in that was ultimately found
/// and linked successfully on the target system or `None` otherwise. See
/// [`has_library()`](Self::has_library()) for more information.
pub fn find_first_library<'a>(&self, libraries: &'a [&str]) -> Option<&'a str> {
for lib in libraries {
if self.has_library(lib) {
return Some(*lib);
}
}
None
}
/// Returns the first library from those provided that can be successfully linked and contains
/// all named `symbols`.
///
/// Returns a reference to the first library name that was passed in that was ultimately found
/// on the target system and contains all the symbol names provided, or `None` if no such
/// library was found. See [`has_library()`](Self::has_library()) and [`has_symbol()`] for more
/// information.
///
/// [`has_symbol()`]: Self::has_symbol()
pub fn find_first_library_with<'a>(
&self,
libraries: &'a [&str],
symbols: &[&str],
) -> Option<&'a str> {
for lib in libraries {
if !self.has_library(lib) {
continue;
}
if self.has_symbols_in(symbols, &[lib]) {
return Some(lib);
}
}
None
}
/// Checks whether the [`cc::Build`] passed to [`Target::new()`] as configured can pull in the
/// named `header` file.
///
/// If including `header` requires pulling in additional headers before it to compile, use
/// [`has_headers()`](Self::has_headers) instead to include multiple headers in the order
/// they're specified.
pub fn has_header(&self, header: &str) -> bool {
let snippet = format!(snippet!("has_header.c"), to_include(header));
self.build(
header,
BuildMode::ObjectFile,
&snippet,
Self::NONE,
Self::NULL_CB,
)
.is_ok()
}
/// Checks whether the [`cc::Build`] passed to [`Target::new()`] as configured can pull in the
/// named `headers` in the order they're provided.
pub fn has_headers(&self, headers: &[&str]) -> bool {
let stub = headers.first().copied().unwrap_or("has_headers");
let snippet = format!(snippet!("has_header.c"), to_includes(headers));
self.build(
stub,
BuildMode::ObjectFile,
&snippet,
Self::NONE,
Self::NULL_CB,
)
.is_ok()
}
/// A convenience function that links against `library` if it is found and linkable.
///
/// This is internally a call to [`has_library()`](Self::has_library()) followed by a
/// conditional call to [`link_library()`].
pub fn try_link_library(&self, library: &str, how: LinkType) -> bool {
if self.has_library(library) {
link_library(library, how);
return true;
}
false
}
/// A convenience function that links against `libraries` only if they are all found and
/// linkable.
///
/// This is internally a call to [`has_libraries()`](Self::has_libraries()) followed by a
/// conditional call to [`link_libraries()`].
pub fn try_link_libraries(&self, libraries: &[&str], how: LinkType) -> bool {
if self.has_libraries(libraries) {
link_libraries(libraries, how);
return true;
}
false
}
/// Evaluates whether or not `define` is an extant preprocessor definition.
///
/// This is the C equivalent of `#ifdef xxxx` and does not check if there is a value associated
/// with the definition. (You can use [`r#if()`](Self::if()) to test if a define has a particular
/// value.)
pub fn ifdef(&self, define: &str, headers: &[&str]) -> bool {
let snippet = format!(snippet!("ifdef.c"), to_includes(headers), define);
self.build(
define,
BuildMode::ObjectFile,
&snippet,
Self::NONE,
Self::NULL_CB,
)
.is_ok()
}
/// Evaluates whether or not `condition` evaluates to true at the C preprocessor time.
///
/// This can be used with `condition` set to `defined(FOO)` to perform the equivalent of
/// [`ifdef()`](Self::ifdef) or it can be used to check for specific values e.g. with
/// `condition` set to something like `FOO != 0`.
pub fn r#if(&self, condition: &str, headers: &[&str]) -> bool {
let snippet = format!(snippet!("if.c"), to_includes(headers), condition);
self.build(
condition,
BuildMode::ObjectFile,
&snippet,
Self::NONE,
Self::NULL_CB,
)
.is_ok()
}
/// Attempts to retrieve the definition of `ident` as an `i32` value.
///
/// Returns `Ok` in case `ident` was defined, has a concrete value, is a compile-time constant
/// (i.e. does not need to be linked to retrieve the value), and is a valid `i32` value.
///
/// # Cross-compliation note:
///
/// The `get_xxx_value()` methods do not currently support cross-compilation scenarios as they
/// require being able to run a binary compiled for the target platform.
pub fn get_i32_value(&self, ident: &str, headers: &[&str]) -> Result<i32, BoxedError> {
let snippet = format!(snippet!("get_i32_value.c"), to_includes(headers), ident);
let exe = self.build(
ident,
BuildMode::Executable,
&snippet,
Self::NONE,
Self::NULL_CB,
)?;
let output = Command::new(exe).output().map_err(|err| {
format!(
"Failed to run the test executable: {err}!\n{}",
"Note that get_i32_value() does not support cross-compilation!"
)
})?;
Ok(std::str::from_utf8(&output.stdout)?.parse()?)
}
/// Attempts to retrieve the definition of `ident` as a `u32` value.
///
/// Returns `Ok` in case `ident` was defined, has a concrete value, is a compile-time constant
/// (i.e. does not need to be linked to retrieve the value), and is a valid `u32` value.
///
/// # Cross-compliation note:
///
/// The `get_xxx_value()` methods do not currently support cross-compilation scenarios as they
/// require being able to run a binary compiled for the target platform.
pub fn get_u32_value(&self, ident: &str, headers: &[&str]) -> Result<u32, BoxedError> {
let snippet = format!(snippet!("get_u32_value.c"), to_includes(headers), ident);
let exe = self.build(
ident,
BuildMode::Executable,
&snippet,
Self::NONE,
Self::NULL_CB,
)?;
let output = Command::new(exe).output().map_err(|err| {
format!(
"Failed to run the test executable: {err}!\n{}",
"Note that get_u32_value() does not support cross-compilation!"
)
})?;
Ok(std::str::from_utf8(&output.stdout)?.parse()?)
}
/// Attempts to retrieve the definition of `ident` as an `i64` value.
///
/// Returns `Ok` in case `ident` was defined, has a concrete value, is a compile-time constant
/// (i.e. does not need to be linked to retrieve the value), and is a valid `i64` value.
///
/// # Cross-compliation note:
///
/// The `get_xxx_value()` methods do not currently support cross-compilation scenarios as they
/// require being able to run a binary compiled for the target platform.
pub fn get_i64_value(&self, ident: &str, headers: &[&str]) -> Result<i64, BoxedError> {
let snippet = format!(snippet!("get_i64_value.c"), to_includes(headers), ident);
let exe = self.build(
ident,
BuildMode::Executable,
&snippet,
Self::NONE,
Self::NULL_CB,
)?;
let output = Command::new(exe).output().map_err(|err| {
format!(
"Failed to run the test executable: {err}!\n{}",
"Note that get_i64_value() does not support cross-compilation!"
)
})?;
Ok(std::str::from_utf8(&output.stdout)?.parse()?)
}
/// Attempts to retrieve the definition of `ident` as a `u64` value.
///
/// Returns `Ok` in case `ident` was defined, has a concrete value, is a compile-time constant
/// (i.e. does not need to be linked to retrieve the value), and is a valid `u64` value.
///
/// # Cross-compliation note:
///
/// The `get_xxx_value()` methods do not currently support cross-compilation scenarios as they
/// require being able to run a binary compiled for the target platform.
pub fn get_u64_value(&self, ident: &str, headers: &[&str]) -> Result<u64, BoxedError> {
let snippet = format!(snippet!("get_u64_value.c"), to_includes(headers), ident);
let exe = self.build(
ident,
BuildMode::Executable,
&snippet,
Self::NONE,
Self::NULL_CB,
)?;
let output = Command::new(exe).output().map_err(|err| {
format!(
"Failed to run the test executable: {err}!\n{}",
"Note that get_u64_value() does not support cross-compilation!"
)
})?;
Ok(std::str::from_utf8(&output.stdout)?.parse()?)
}
/// Retrieve the definition of a C preprocessor macro or define.
///
/// For "function macros" like `max(x, y)`, make sure to supply parentheses and pass in
/// placeholders for the parameters (like the `x` and `y` in the example); they will be returned
/// as-is in the expanded output.
pub fn get_macro_value(
&self,
ident: &str,
headers: &[&str],
) -> Result<Option<String>, BoxedError> {
// We use `ident` twice: to check if it's defined then to get its value
// For "function macros", the first should be without parentheses!
let bare_name = if let Some(idx) = ident.find('(') {
std::str::from_utf8(&ident.as_bytes()[..idx]).unwrap()
} else {
ident
};
let snippet = format!(
snippet!("get_macro_value.c"),
to_includes(headers),
bare_name,
ident
);
let mut result = None;
let callback = |stdout: &str, stderr: &str| {
let buffer = if self.is_cl { &stdout } else { &stderr };
if let Some(start) = buffer.find("EXFIL:::").map(|i| i + "EXFIL:::".len()) {
let start = std::str::from_utf8(&buffer.as_bytes()[start..]).unwrap();
let end = start
.find(":::EXFIL")
.expect("Did not find terminating :::EXFIL sequence!");
result = Some(
std::str::from_utf8(&start.as_bytes()[..end])
.unwrap()
.to_string(),
);
}
};
self.build(ident, BuildMode::ObjectFile, &snippet, Self::NONE, callback)
.map_err(|err| {
format!(
"Test compilation failure. Is ident `{}` valid?\n{}",
bare_name, err
)
})?;
Ok(result)
}
/// Retrieve the definition of a C preprocessor macro or define, recursively in case it is
/// defined in terms of another `#define`.
///
/// For "function macros" like `max(x, y)`, make sure to pass in placeholders for the parameters
/// (they will be returned as-is in the expanded output).
pub fn get_macro_value_recursive(
&self,
ident: &str,
headers: &[&str],
) -> Result<Option<String>, BoxedError> {
let mut result = self.get_macro_value(ident, headers)?;
while result.is_some() {
// We shouldn't bubble up recursive errors because a macro can expand to a value that
// isn't a valid macro name (such as an expression wrapped in parentheses).
match self.get_macro_value(result.as_ref().unwrap(), headers) {
Ok(Some(r)) => result = Some(r),
_ => break,
};
}
Ok(result)
}
}
impl From<cc::Build> for Target {
fn from(build: cc::Build) -> Self {
Self::new_from(build).unwrap()
}
}
/// Sanitizes a string for use in a file name
fn fs_sanitize(s: &str) -> Cow<'_, str> {
if s.chars().all(|c| c.is_ascii_alphanumeric() || c == '_') {
return Cow::Borrowed(s);
}
let mut out = String::with_capacity(s.len());
for c in s.chars() {
if !c.is_ascii_alphanumeric() {
out.push('_');
} else {
out.push(c);
}
}
Cow::Owned(out)
}
/// Convert header filename `header` to a `#include <..>` statement.
fn to_include(header: &str) -> String {
format!("#include <{}>", header)
}
/// Convert one or more header filenames `headers` to `#include <..>` statements.
fn to_includes(headers: &[&str]) -> String {
let mut vec = Vec::with_capacity(headers.len());
vec.extend(headers.iter().copied().map(to_include));
vec.join("\n")
}
/// Returns the `(Major, Minor, Patch)` version of the in-use `rustc` compiler.
///
/// Returns `None` in case of unexpected output format and panics in the event of runtime invariants
/// being violated (i.e. non-executable RUSTC_WRAPPER, non-UTF-8 output, etc).
fn rustc_version() -> Option<(u8, u8, u8)> {
use std::env;
use std::sync::OnceLock;
static RUSTC_VERSION: OnceLock<Option<(u8, u8, u8)>> = OnceLock::new();
RUSTC_VERSION
.get_or_init(|| -> Option<(u8, u8, u8)> {
let rustc = env::var_os("RUSTC").unwrap_or_else(|| OsString::from("rustc"));
let mut cmd = match env::var_os("RUSTC_WRAPPER").filter(|w| !w.is_empty()) {
Some(wrapper) => {
let mut cmd = Command::new(wrapper);
cmd.arg(rustc);
cmd
}
None => Command::new(rustc),
};
let cmd = cmd.arg("--version");
let output = cmd.output().expect("Failed to execute rustc!");
let mut parts = std::str::from_utf8(&output.stdout)
.expect("Failed to parse `rustc --version` to UTF-8!")
.strip_prefix("rustc ")
// 1.80.0 or 1.80.0-nightly
.and_then(|output| output.split(|c| c == ' ' || c == '-').next())?
.split('.')
.map_while(|v| u8::from_str_radix(v, 10).ok());
Some((parts.next()?, parts.next()?, parts.next()?))
})
.clone()
}
#[test]
fn rustc_version_test() {
assert!(matches!(rustc_version(), Some((_major, _minor, _patch))));
}