diff options
Diffstat (limited to 'vendor/anyhow/src/backtrace.rs')
| -rw-r--r-- | vendor/anyhow/src/backtrace.rs | 401 |
1 files changed, 401 insertions, 0 deletions
diff --git a/vendor/anyhow/src/backtrace.rs b/vendor/anyhow/src/backtrace.rs new file mode 100644 index 000000000..e4c907641 --- /dev/null +++ b/vendor/anyhow/src/backtrace.rs @@ -0,0 +1,401 @@ +#[cfg(backtrace)] +pub(crate) use std::backtrace::{Backtrace, BacktraceStatus}; + +#[cfg(all(not(backtrace), feature = "backtrace"))] +pub(crate) use self::capture::{Backtrace, BacktraceStatus}; + +#[cfg(not(any(backtrace, feature = "backtrace")))] +pub(crate) enum Backtrace {} + +#[cfg(backtrace)] +macro_rules! impl_backtrace { + () => { + std::backtrace::Backtrace + }; +} + +#[cfg(all(not(backtrace), feature = "backtrace"))] +macro_rules! impl_backtrace { + () => { + impl core::fmt::Debug + core::fmt::Display + }; +} + +#[cfg(any(backtrace, feature = "backtrace"))] +macro_rules! backtrace { + () => { + Some(crate::backtrace::Backtrace::capture()) + }; +} + +#[cfg(not(any(backtrace, feature = "backtrace")))] +macro_rules! backtrace { + () => { + None + }; +} + +#[cfg(backtrace)] +macro_rules! backtrace_if_absent { + ($err:expr) => { + match $err.backtrace() { + Some(_) => None, + None => backtrace!(), + } + }; +} + +#[cfg(all(feature = "std", not(backtrace), feature = "backtrace"))] +macro_rules! backtrace_if_absent { + ($err:expr) => { + backtrace!() + }; +} + +#[cfg(all(feature = "std", not(backtrace), not(feature = "backtrace")))] +macro_rules! backtrace_if_absent { + ($err:expr) => { + None + }; +} + +#[cfg(all(not(backtrace), feature = "backtrace"))] +mod capture { + use backtrace::{BacktraceFmt, BytesOrWideString, Frame, PrintFmt, SymbolName}; + use core::cell::UnsafeCell; + use core::fmt::{self, Debug, Display}; + use core::sync::atomic::{AtomicUsize, Ordering}; + use std::borrow::Cow; + use std::env; + use std::path::{self, Path, PathBuf}; + use std::sync::Once; + + pub(crate) struct Backtrace { + inner: Inner, + } + + pub(crate) enum BacktraceStatus { + Unsupported, + Disabled, + Captured, + } + + enum Inner { + Unsupported, + Disabled, + Captured(LazilyResolvedCapture), + } + + struct Capture { + actual_start: usize, + resolved: bool, + frames: Vec<BacktraceFrame>, + } + + struct BacktraceFrame { + frame: Frame, + symbols: Vec<BacktraceSymbol>, + } + + struct BacktraceSymbol { + name: Option<Vec<u8>>, + filename: Option<BytesOrWide>, + lineno: Option<u32>, + colno: Option<u32>, + } + + enum BytesOrWide { + Bytes(Vec<u8>), + Wide(Vec<u16>), + } + + impl Debug for Backtrace { + fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { + let capture = match &self.inner { + Inner::Unsupported => return fmt.write_str("<unsupported>"), + Inner::Disabled => return fmt.write_str("<disabled>"), + Inner::Captured(c) => c.force(), + }; + + let frames = &capture.frames[capture.actual_start..]; + + write!(fmt, "Backtrace ")?; + + let mut dbg = fmt.debug_list(); + + for frame in frames { + if frame.frame.ip().is_null() { + continue; + } + + dbg.entries(&frame.symbols); + } + + dbg.finish() + } + } + + impl Debug for BacktraceFrame { + fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { + let mut dbg = fmt.debug_list(); + dbg.entries(&self.symbols); + dbg.finish() + } + } + + impl Debug for BacktraceSymbol { + fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { + write!(fmt, "{{ ")?; + + if let Some(fn_name) = self.name.as_ref().map(|b| SymbolName::new(b)) { + write!(fmt, "fn: \"{:#}\"", fn_name)?; + } else { + write!(fmt, "fn: <unknown>")?; + } + + if let Some(fname) = self.filename.as_ref() { + write!(fmt, ", file: \"{:?}\"", fname)?; + } + + if let Some(line) = self.lineno { + write!(fmt, ", line: {:?}", line)?; + } + + write!(fmt, " }}") + } + } + + impl Debug for BytesOrWide { + fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { + output_filename( + fmt, + match self { + BytesOrWide::Bytes(w) => BytesOrWideString::Bytes(w), + BytesOrWide::Wide(w) => BytesOrWideString::Wide(w), + }, + PrintFmt::Short, + env::current_dir().as_ref().ok(), + ) + } + } + + impl Backtrace { + fn enabled() -> bool { + static ENABLED: AtomicUsize = AtomicUsize::new(0); + match ENABLED.load(Ordering::Relaxed) { + 0 => {} + 1 => return false, + _ => return true, + } + let enabled = match env::var_os("RUST_LIB_BACKTRACE") { + Some(s) => s != "0", + None => match env::var_os("RUST_BACKTRACE") { + Some(s) => s != "0", + None => false, + }, + }; + ENABLED.store(enabled as usize + 1, Ordering::Relaxed); + enabled + } + + #[inline(never)] // want to make sure there's a frame here to remove + pub(crate) fn capture() -> Backtrace { + if Backtrace::enabled() { + Backtrace::create(Backtrace::capture as usize) + } else { + let inner = Inner::Disabled; + Backtrace { inner } + } + } + + // Capture a backtrace which starts just before the function addressed + // by `ip` + fn create(ip: usize) -> Backtrace { + let mut frames = Vec::new(); + let mut actual_start = None; + backtrace::trace(|frame| { + frames.push(BacktraceFrame { + frame: frame.clone(), + symbols: Vec::new(), + }); + if frame.symbol_address() as usize == ip && actual_start.is_none() { + actual_start = Some(frames.len() + 1); + } + true + }); + + // If no frames came out assume that this is an unsupported platform + // since `backtrace` doesn't provide a way of learning this right + // now, and this should be a good enough approximation. + let inner = if frames.is_empty() { + Inner::Unsupported + } else { + Inner::Captured(LazilyResolvedCapture::new(Capture { + actual_start: actual_start.unwrap_or(0), + frames, + resolved: false, + })) + }; + + Backtrace { inner } + } + + pub(crate) fn status(&self) -> BacktraceStatus { + match self.inner { + Inner::Unsupported => BacktraceStatus::Unsupported, + Inner::Disabled => BacktraceStatus::Disabled, + Inner::Captured(_) => BacktraceStatus::Captured, + } + } + } + + impl Display for Backtrace { + fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { + let capture = match &self.inner { + Inner::Unsupported => return fmt.write_str("unsupported backtrace"), + Inner::Disabled => return fmt.write_str("disabled backtrace"), + Inner::Captured(c) => c.force(), + }; + + let full = fmt.alternate(); + let (frames, style) = if full { + (&capture.frames[..], PrintFmt::Full) + } else { + (&capture.frames[capture.actual_start..], PrintFmt::Short) + }; + + // When printing paths we try to strip the cwd if it exists, + // otherwise we just print the path as-is. Note that we also only do + // this for the short format, because if it's full we presumably + // want to print everything. + let cwd = env::current_dir(); + let mut print_path = move |fmt: &mut fmt::Formatter, path: BytesOrWideString| { + output_filename(fmt, path, style, cwd.as_ref().ok()) + }; + + let mut f = BacktraceFmt::new(fmt, style, &mut print_path); + f.add_context()?; + for frame in frames { + let mut f = f.frame(); + if frame.symbols.is_empty() { + f.print_raw(frame.frame.ip(), None, None, None)?; + } else { + for symbol in frame.symbols.iter() { + f.print_raw_with_column( + frame.frame.ip(), + symbol.name.as_ref().map(|b| SymbolName::new(b)), + symbol.filename.as_ref().map(|b| match b { + BytesOrWide::Bytes(w) => BytesOrWideString::Bytes(w), + BytesOrWide::Wide(w) => BytesOrWideString::Wide(w), + }), + symbol.lineno, + symbol.colno, + )?; + } + } + } + f.finish()?; + Ok(()) + } + } + + struct LazilyResolvedCapture { + sync: Once, + capture: UnsafeCell<Capture>, + } + + impl LazilyResolvedCapture { + fn new(capture: Capture) -> Self { + LazilyResolvedCapture { + sync: Once::new(), + capture: UnsafeCell::new(capture), + } + } + + fn force(&self) -> &Capture { + self.sync.call_once(|| { + // Safety: This exclusive reference can't overlap with any + // others. `Once` guarantees callers will block until this + // closure returns. `Once` also guarantees only a single caller + // will enter this closure. + unsafe { &mut *self.capture.get() }.resolve(); + }); + + // Safety: This shared reference can't overlap with the exclusive + // reference above. + unsafe { &*self.capture.get() } + } + } + + // Safety: Access to the inner value is synchronized using a thread-safe + // `Once`. So long as `Capture` is `Sync`, `LazilyResolvedCapture` is too + unsafe impl Sync for LazilyResolvedCapture where Capture: Sync {} + + impl Capture { + fn resolve(&mut self) { + // If we're already resolved, nothing to do! + if self.resolved { + return; + } + self.resolved = true; + + for frame in self.frames.iter_mut() { + let symbols = &mut frame.symbols; + let frame = &frame.frame; + backtrace::resolve_frame(frame, |symbol| { + symbols.push(BacktraceSymbol { + name: symbol.name().map(|m| m.as_bytes().to_vec()), + filename: symbol.filename_raw().map(|b| match b { + BytesOrWideString::Bytes(b) => BytesOrWide::Bytes(b.to_owned()), + BytesOrWideString::Wide(b) => BytesOrWide::Wide(b.to_owned()), + }), + lineno: symbol.lineno(), + colno: symbol.colno(), + }); + }); + } + } + } + + // Prints the filename of the backtrace frame. + fn output_filename( + fmt: &mut fmt::Formatter, + bows: BytesOrWideString, + print_fmt: PrintFmt, + cwd: Option<&PathBuf>, + ) -> fmt::Result { + let file: Cow<Path> = match bows { + #[cfg(unix)] + BytesOrWideString::Bytes(bytes) => { + use std::os::unix::ffi::OsStrExt; + Path::new(std::ffi::OsStr::from_bytes(bytes)).into() + } + #[cfg(not(unix))] + BytesOrWideString::Bytes(bytes) => { + Path::new(std::str::from_utf8(bytes).unwrap_or("<unknown>")).into() + } + #[cfg(windows)] + BytesOrWideString::Wide(wide) => { + use std::os::windows::ffi::OsStringExt; + Cow::Owned(std::ffi::OsString::from_wide(wide).into()) + } + #[cfg(not(windows))] + BytesOrWideString::Wide(_wide) => Path::new("<unknown>").into(), + }; + if print_fmt == PrintFmt::Short && file.is_absolute() { + if let Some(cwd) = cwd { + if let Ok(stripped) = file.strip_prefix(&cwd) { + if let Some(s) = stripped.to_str() { + return write!(fmt, ".{}{}", path::MAIN_SEPARATOR, s); + } + } + } + } + Display::fmt(&file.display(), fmt) + } +} + +fn _assert_send_sync() { + fn _assert<T: Send + Sync>() {} + _assert::<Backtrace>(); +} |