diff --git a/library/std/src/backtrace.rs b/library/std/src/backtrace.rs index 95e18ef2a6543..0aae4674b2942 100644 --- a/library/std/src/backtrace.rs +++ b/library/std/src/backtrace.rs @@ -147,11 +147,14 @@ fn _assert_send_sync() { _assert::(); } -struct BacktraceFrame { +/// A single frame of a backtrace. +#[unstable(feature = "backtrace_frames", issue = "79676")] +pub struct BacktraceFrame { frame: RawFrame, symbols: Vec, } +#[derive(Debug)] enum RawFrame { Actual(backtrace_rs::Frame), #[cfg(test)] @@ -196,6 +199,14 @@ impl fmt::Debug for Backtrace { } } +impl fmt::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 fmt::Debug for BacktraceSymbol { fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { // FIXME: improve formatting: https://github.com/rust-lang/rust/issues/65280 @@ -353,6 +364,14 @@ impl Backtrace { } } +impl<'a> Backtrace { + /// Returns an iterator over the backtrace frames. + #[unstable(feature = "backtrace_frames", issue = "79676")] + pub fn frames(&'a self) -> &'a [BacktraceFrame] { + if let Inner::Captured(c) = &self.inner { &c.force().frames } else { &[] } + } +} + impl fmt::Display for Backtrace { fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { let capture = match &self.inner { diff --git a/library/std/src/backtrace/tests.rs b/library/std/src/backtrace/tests.rs index 31cf0f702185c..f5da93f93fd93 100644 --- a/library/std/src/backtrace/tests.rs +++ b/library/std/src/backtrace/tests.rs @@ -1,48 +1,52 @@ use super::*; +fn generate_fake_frames() -> Vec { + vec![ + BacktraceFrame { + frame: RawFrame::Fake, + symbols: vec![BacktraceSymbol { + name: Some(b"std::backtrace::Backtrace::create".to_vec()), + filename: Some(BytesOrWide::Bytes(b"rust/backtrace.rs".to_vec())), + lineno: Some(100), + colno: None, + }], + }, + BacktraceFrame { + frame: RawFrame::Fake, + symbols: vec![BacktraceSymbol { + name: Some(b"__rust_maybe_catch_panic".to_vec()), + filename: None, + lineno: None, + colno: None, + }], + }, + BacktraceFrame { + frame: RawFrame::Fake, + symbols: vec![ + BacktraceSymbol { + name: Some(b"std::rt::lang_start_internal".to_vec()), + filename: Some(BytesOrWide::Bytes(b"rust/rt.rs".to_vec())), + lineno: Some(300), + colno: Some(5), + }, + BacktraceSymbol { + name: Some(b"std::rt::lang_start".to_vec()), + filename: Some(BytesOrWide::Bytes(b"rust/rt.rs".to_vec())), + lineno: Some(400), + colno: None, + }, + ], + }, + ] +} + #[test] fn test_debug() { let backtrace = Backtrace { inner: Inner::Captured(LazilyResolvedCapture::new(Capture { actual_start: 1, resolved: true, - frames: vec![ - BacktraceFrame { - frame: RawFrame::Fake, - symbols: vec![BacktraceSymbol { - name: Some(b"std::backtrace::Backtrace::create".to_vec()), - filename: Some(BytesOrWide::Bytes(b"rust/backtrace.rs".to_vec())), - lineno: Some(100), - colno: None, - }], - }, - BacktraceFrame { - frame: RawFrame::Fake, - symbols: vec![BacktraceSymbol { - name: Some(b"__rust_maybe_catch_panic".to_vec()), - filename: None, - lineno: None, - colno: None, - }], - }, - BacktraceFrame { - frame: RawFrame::Fake, - symbols: vec![ - BacktraceSymbol { - name: Some(b"std::rt::lang_start_internal".to_vec()), - filename: Some(BytesOrWide::Bytes(b"rust/rt.rs".to_vec())), - lineno: Some(300), - colno: Some(5), - }, - BacktraceSymbol { - name: Some(b"std::rt::lang_start".to_vec()), - filename: Some(BytesOrWide::Bytes(b"rust/rt.rs".to_vec())), - lineno: Some(400), - colno: None, - }, - ], - }, - ], + frames: generate_fake_frames(), })), }; @@ -58,3 +62,34 @@ fn test_debug() { // Format the backtrace a second time, just to make sure lazily resolved state is stable assert_eq!(format!("{:#?}", backtrace), expected); } + +#[test] +fn test_frames() { + let backtrace = Backtrace { + inner: Inner::Captured(LazilyResolvedCapture::new(Capture { + actual_start: 1, + resolved: true, + frames: generate_fake_frames(), + })), + }; + + let frames = backtrace.frames(); + + #[rustfmt::skip] + let expected = vec![ + "[ + { fn: \"std::backtrace::Backtrace::create\", file: \"rust/backtrace.rs\", line: 100 }, +]", + "[ + { fn: \"__rust_maybe_catch_panic\" }, +]", + "[ + { fn: \"std::rt::lang_start_internal\", file: \"rust/rt.rs\", line: 300 }, + { fn: \"std::rt::lang_start\", file: \"rust/rt.rs\", line: 400 }, +]" + ]; + + let mut iter = frames.iter().zip(expected.iter()); + + assert!(iter.all(|(f, e)| format!("{:#?}", f) == *e)); +}