1//! Miscellaneous helpers for running commands
2
3use std::{
4 borrow::Cow,
5 collections::hash_map,
6 ffi::OsString,
7 fmt::Display,
8 fs,
9 hash::Hasher,
10 io::{self, Read, Write},
11 path::Path,
12 process::{Child, ChildStderr, Command, Stdio},
13 sync::{
14 atomic::{AtomicBool, Ordering},
15 Arc,
16 },
17};
18
19use crate::{Error, ErrorKind, Object};
20
21#[derive(Clone, Debug)]
22pub(crate) struct CargoOutput {
23 pub(crate) metadata: bool,
24 pub(crate) warnings: bool,
25 pub(crate) debug: bool,
26 pub(crate) output: OutputKind,
27 checked_dbg_var: Arc<AtomicBool>,
28}
29
30/// Different strategies for handling compiler output (to stdout)
31#[derive(Clone, Debug)]
32pub(crate) enum OutputKind {
33 /// Forward the output to this process' stdout ([`Stdio::inherit()`])
34 Forward,
35 /// Discard the output ([`Stdio::null()`])
36 Discard,
37 /// Capture the result (`[Stdio::piped()`])
38 Capture,
39}
40
41impl CargoOutput {
42 pub(crate) fn new() -> Self {
43 #[allow(clippy::disallowed_methods)]
44 Self {
45 metadata: true,
46 warnings: true,
47 output: OutputKind::Forward,
48 debug: match std::env::var_os("CC_ENABLE_DEBUG_OUTPUT") {
49 Some(v) => v != "0" && v != "false" && v != "",
50 None => false,
51 },
52 checked_dbg_var: Arc::new(AtomicBool::new(false)),
53 }
54 }
55
56 pub(crate) fn print_metadata(&self, s: &dyn Display) {
57 if self.metadata {
58 println!("{}", s);
59 }
60 }
61
62 pub(crate) fn print_warning(&self, arg: &dyn Display) {
63 if self.warnings {
64 println!("cargo:warning={}", arg);
65 }
66 }
67
68 pub(crate) fn print_debug(&self, arg: &dyn Display) {
69 if self.metadata && !self.checked_dbg_var.load(Ordering::Relaxed) {
70 self.checked_dbg_var.store(true, Ordering::Relaxed);
71 println!("cargo:rerun-if-env-changed=CC_ENABLE_DEBUG_OUTPUT");
72 }
73 if self.debug {
74 println!("{}", arg);
75 }
76 }
77
78 fn stdio_for_warnings(&self) -> Stdio {
79 if self.warnings {
80 Stdio::piped()
81 } else {
82 Stdio::null()
83 }
84 }
85
86 fn stdio_for_output(&self) -> Stdio {
87 match self.output {
88 OutputKind::Capture => Stdio::piped(),
89 OutputKind::Forward => Stdio::inherit(),
90 OutputKind::Discard => Stdio::null(),
91 }
92 }
93}
94
95pub(crate) struct StderrForwarder {
96 inner: Option<(ChildStderr, Vec<u8>)>,
97 #[cfg(feature = "parallel")]
98 is_non_blocking: bool,
99 #[cfg(feature = "parallel")]
100 bytes_available_failed: bool,
101 /// number of bytes buffered in inner
102 bytes_buffered: usize,
103}
104
105const MIN_BUFFER_CAPACITY: usize = 100;
106
107impl StderrForwarder {
108 pub(crate) fn new(child: &mut Child) -> Self {
109 Self {
110 inner: child
111 .stderr
112 .take()
113 .map(|stderr| (stderr, Vec::with_capacity(MIN_BUFFER_CAPACITY))),
114 bytes_buffered: 0,
115 #[cfg(feature = "parallel")]
116 is_non_blocking: false,
117 #[cfg(feature = "parallel")]
118 bytes_available_failed: false,
119 }
120 }
121
122 fn forward_available(&mut self) -> bool {
123 if let Some((stderr, buffer)) = self.inner.as_mut() {
124 loop {
125 // For non-blocking we check to see if there is data available, so we should try to
126 // read at least that much. For blocking, always read at least the minimum amount.
127 #[cfg(not(feature = "parallel"))]
128 let to_reserve = MIN_BUFFER_CAPACITY;
129 #[cfg(feature = "parallel")]
130 let to_reserve = if self.is_non_blocking && !self.bytes_available_failed {
131 match crate::parallel::stderr::bytes_available(stderr) {
132 #[cfg(windows)]
133 Ok(0) => break false,
134 #[cfg(unix)]
135 Ok(0) => {
136 // On Unix, depending on the implementation, we may sometimes get 0 in a
137 // loop (either there is data available or the pipe is broken), so
138 // continue with the non-blocking read anyway.
139 MIN_BUFFER_CAPACITY
140 }
141 #[cfg(windows)]
142 Err(_) => {
143 // On Windows, if we get an error then the pipe is broken, so flush
144 // the buffer and bail.
145 if !buffer.is_empty() {
146 write_warning(&buffer[..]);
147 }
148 self.inner = None;
149 break true;
150 }
151 #[cfg(unix)]
152 Err(_) => {
153 // On Unix, depending on the implementation, we may get spurious
154 // errors so make a note not to use bytes_available again and try
155 // the non-blocking read anyway.
156 self.bytes_available_failed = true;
157 MIN_BUFFER_CAPACITY
158 }
159 #[cfg(target_family = "wasm")]
160 Err(_) => panic!("bytes_available should always succeed on wasm"),
161 Ok(bytes_available) => MIN_BUFFER_CAPACITY.max(bytes_available),
162 }
163 } else {
164 MIN_BUFFER_CAPACITY
165 };
166 if self.bytes_buffered + to_reserve > buffer.len() {
167 buffer.resize(self.bytes_buffered + to_reserve, 0);
168 }
169
170 match stderr.read(&mut buffer[self.bytes_buffered..]) {
171 Err(err) if err.kind() == std::io::ErrorKind::WouldBlock => {
172 // No data currently, yield back.
173 break false;
174 }
175 Err(err) if err.kind() == std::io::ErrorKind::Interrupted => {
176 // Interrupted, try again.
177 continue;
178 }
179 Ok(bytes_read) if bytes_read != 0 => {
180 self.bytes_buffered += bytes_read;
181 let mut consumed = 0;
182 for line in buffer[..self.bytes_buffered].split_inclusive(|&b| b == b'\n') {
183 // Only forward complete lines, leave the rest in the buffer.
184 if let Some((b'\n', line)) = line.split_last() {
185 consumed += line.len() + 1;
186 write_warning(line);
187 }
188 }
189 if consumed > 0 && consumed < self.bytes_buffered {
190 // Remove the consumed bytes from buffer
191 buffer.copy_within(consumed.., 0);
192 }
193 self.bytes_buffered -= consumed;
194 }
195 res => {
196 // End of stream: flush remaining data and bail.
197 if self.bytes_buffered > 0 {
198 write_warning(&buffer[..self.bytes_buffered]);
199 }
200 if let Err(err) = res {
201 write_warning(
202 format!("Failed to read from child stderr: {err}").as_bytes(),
203 );
204 }
205 self.inner.take();
206 break true;
207 }
208 }
209 }
210 } else {
211 true
212 }
213 }
214
215 #[cfg(feature = "parallel")]
216 pub(crate) fn set_non_blocking(&mut self) -> Result<(), Error> {
217 assert!(!self.is_non_blocking);
218
219 #[cfg(unix)]
220 if let Some((stderr, _)) = self.inner.as_ref() {
221 crate::parallel::stderr::set_non_blocking(stderr)?;
222 }
223
224 self.is_non_blocking = true;
225 Ok(())
226 }
227
228 #[cfg(feature = "parallel")]
229 fn forward_all(&mut self) {
230 while !self.forward_available() {}
231 }
232
233 #[cfg(not(feature = "parallel"))]
234 fn forward_all(&mut self) {
235 let forward_result = self.forward_available();
236 assert!(forward_result, "Should have consumed all data");
237 }
238}
239
240fn write_warning(line: &[u8]) {
241 let stdout: Stdout = io::stdout();
242 let mut stdout: StdoutLock<'static> = stdout.lock();
243 stdout.write_all(buf:b"cargo:warning=").unwrap();
244 stdout.write_all(buf:line).unwrap();
245 stdout.write_all(buf:b"\n").unwrap();
246}
247
248fn wait_on_child(
249 cmd: &Command,
250 child: &mut Child,
251 cargo_output: &CargoOutput,
252) -> Result<(), Error> {
253 StderrForwarder::new(child).forward_all();
254
255 let status: ExitStatus = match child.wait() {
256 Ok(s: ExitStatus) => s,
257 Err(e: Error) => {
258 return Err(Error::new(
259 kind:ErrorKind::ToolExecError,
260 message:format!("failed to wait on spawned child process `{cmd:?}`: {e}"),
261 ));
262 }
263 };
264
265 cargo_output.print_debug(&status);
266
267 if status.success() {
268 Ok(())
269 } else {
270 Err(Error::new(
271 kind:ErrorKind::ToolExecError,
272 message:format!("command did not execute successfully (status code {status}): {cmd:?}"),
273 ))
274 }
275}
276
277/// Find the destination object path for each file in the input source files,
278/// and store them in the output Object.
279pub(crate) fn objects_from_files(files: &[Arc<Path>], dst: &Path) -> Result<Vec<Object>, Error> {
280 let mut objects = Vec::with_capacity(files.len());
281 for file in files {
282 let basename = file
283 .file_name()
284 .ok_or_else(|| {
285 Error::new(
286 ErrorKind::InvalidArgument,
287 "No file_name for object file path!",
288 )
289 })?
290 .to_string_lossy();
291 let dirname = file
292 .parent()
293 .ok_or_else(|| {
294 Error::new(
295 ErrorKind::InvalidArgument,
296 "No parent for object file path!",
297 )
298 })?
299 .to_string_lossy();
300
301 // Hash the dirname. This should prevent conflicts if we have multiple
302 // object files with the same filename in different subfolders.
303 let mut hasher = hash_map::DefaultHasher::new();
304
305 // Make the dirname relative (if possible) to avoid full system paths influencing the sha
306 // and making the output system-dependent
307 //
308 // NOTE: Here we allow using std::env::var (instead of Build::getenv) because
309 // CARGO_* variables always trigger a rebuild when changed
310 #[allow(clippy::disallowed_methods)]
311 let dirname = if let Some(root) = std::env::var_os("CARGO_MANIFEST_DIR") {
312 let root = root.to_string_lossy();
313 Cow::Borrowed(dirname.strip_prefix(&*root).unwrap_or(&dirname))
314 } else {
315 dirname
316 };
317
318 hasher.write(dirname.as_bytes());
319 if let Some(extension) = file.extension() {
320 hasher.write(extension.to_string_lossy().as_bytes());
321 }
322 let obj = dst
323 .join(format!("{:016x}-{}", hasher.finish(), basename))
324 .with_extension("o");
325
326 match obj.parent() {
327 Some(s) => fs::create_dir_all(s)?,
328 None => {
329 return Err(Error::new(
330 ErrorKind::InvalidArgument,
331 "dst is an invalid path with no parent",
332 ));
333 }
334 };
335
336 objects.push(Object::new(file.to_path_buf(), obj));
337 }
338
339 Ok(objects)
340}
341
342pub(crate) fn run(cmd: &mut Command, cargo_output: &CargoOutput) -> Result<(), Error> {
343 let mut child: Child = spawn(cmd, cargo_output)?;
344 wait_on_child(cmd, &mut child, cargo_output)
345}
346
347pub(crate) fn run_output(cmd: &mut Command, cargo_output: &CargoOutput) -> Result<Vec<u8>, Error> {
348 // We specifically need the output to be captured, so override default
349 let mut captured_cargo_output: CargoOutput = cargo_output.clone();
350 captured_cargo_output.output = OutputKind::Capture;
351 let mut child: Child = spawn(cmd, &captured_cargo_output)?;
352
353 let mut stdout: Vec = vec![];
354 childResult
355 .stdout
356 .take()
357 .unwrap()
358 .read_to_end(&mut stdout)
359 .unwrap();
360
361 // Don't care about this output, use the normal settings
362 wait_on_child(cmd, &mut child, cargo_output)?;
363
364 Ok(stdout)
365}
366
367pub(crate) fn spawn(cmd: &mut Command, cargo_output: &CargoOutput) -> Result<Child, Error> {
368 struct ResetStderr<'cmd>(&'cmd mut Command);
369
370 impl Drop for ResetStderr<'_> {
371 fn drop(&mut self) {
372 // Reset stderr to default to release pipe_writer so that print thread will
373 // not block forever.
374 self.0.stderr(Stdio::inherit());
375 }
376 }
377
378 cargo_output.print_debug(&format_args!("running: {:?}", cmd));
379
380 let cmd = ResetStderr(cmd);
381 let child = cmd
382 .0
383 .stderr(cargo_output.stdio_for_warnings())
384 .stdout(cargo_output.stdio_for_output())
385 .spawn();
386 match child {
387 Ok(child) => Ok(child),
388 Err(ref e) if e.kind() == io::ErrorKind::NotFound => {
389 let extra = if cfg!(windows) {
390 " (see https://docs.rs/cc/latest/cc/#compile-time-requirements for help)"
391 } else {
392 ""
393 };
394 Err(Error::new(
395 ErrorKind::ToolNotFound,
396 format!("failed to find tool {:?}: {e}{extra}", cmd.0.get_program()),
397 ))
398 }
399 Err(e) => Err(Error::new(
400 ErrorKind::ToolExecError,
401 format!("command `{:?}` failed to start: {e}", cmd.0),
402 )),
403 }
404}
405
406pub(crate) struct CmdAddOutputFileArgs {
407 pub(crate) cuda: bool,
408 pub(crate) is_assembler_msvc: bool,
409 pub(crate) msvc: bool,
410 pub(crate) clang: bool,
411 pub(crate) gnu: bool,
412 pub(crate) is_asm: bool,
413 pub(crate) is_arm: bool,
414}
415
416pub(crate) fn command_add_output_file(cmd: &mut Command, dst: &Path, args: CmdAddOutputFileArgs) {
417 if args.is_assembler_msvc
418 || !(!args.msvc || args.clang || args.gnu || args.cuda || (args.is_asm && args.is_arm))
419 {
420 let mut s: OsString = OsString::from("-Fo");
421 s.push(dst);
422 cmd.arg(s);
423 } else {
424 cmd.arg("-o").arg(dst);
425 }
426}
427
428#[cfg(feature = "parallel")]
429pub(crate) fn try_wait_on_child(
430 cmd: &Command,
431 child: &mut Child,
432 stdout: &mut dyn io::Write,
433 stderr_forwarder: &mut StderrForwarder,
434) -> Result<Option<()>, Error> {
435 stderr_forwarder.forward_available();
436
437 match child.try_wait() {
438 Ok(Some(status)) => {
439 stderr_forwarder.forward_all();
440
441 let _ = writeln!(stdout, "{}", status);
442
443 if status.success() {
444 Ok(Some(()))
445 } else {
446 Err(Error::new(
447 ErrorKind::ToolExecError,
448 format!("command did not execute successfully (status code {status}): {cmd:?}"),
449 ))
450 }
451 }
452 Ok(None) => Ok(None),
453 Err(e) => {
454 stderr_forwarder.forward_all();
455 Err(Error::new(
456 ErrorKind::ToolExecError,
457 format!("failed to wait on spawned child process `{cmd:?}`: {e}"),
458 ))
459 }
460 }
461}
462