| @@ -267,14 +267,32 @@ impl Thread { |
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#[cfg(target_os = "espidf")] |
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pub fn sleep(dur: Duration) { |
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-let mut micros = dur.as_micros(); |
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-unsafe { |
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-while micros > 0 { |
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-let st = if micros > u32::MAX as u128 { u32::MAX } else { micros as u32 }; |
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+// ESP-IDF does not have `nanosleep`, so we use `usleep` instead. |
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+// As per the documentation of `usleep`, it is expected to support |
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+// sleep times as big as at least up to 1 second. |
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+// |
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+// ESP-IDF does support almost up to `u32::MAX`, but due to a potential integer overflow in its |
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+// `usleep` implementation |
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+// (https://github.com/espressif/esp-idf/blob/d7ca8b94c852052e3bc33292287ef4dd62c9eeb1/components/newlib/time.c#L210), |
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+// we limit the sleep time to the maximum one that would not cause the underlying `usleep` implementation to overflow |
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+// (`portTICK_PERIOD_MS` can be anything between 1 to 1000, and is 10 by default). |
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+const MAX_MICROS: u32 = u32::MAX - 1_000_000 - 1; |
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+ |
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+// Add any nanoseconds smaller than a microsecond as an extra microsecond |
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+// so as to comply with the `std::thread::sleep` contract which mandates |
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+// implementations to sleep for _at least_ the provided `dur`. |
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+// We can't overflow `micros` as it is a `u128`, while `Duration` is a pair of |
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+// (`u64` secs, `u32` nanos), where the nanos are strictly smaller than 1 second |
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+// (i.e. < 1_000_000_000) |
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+let mut micros = dur.as_micros() + if dur.subsec_nanos() % 1_000 > 0 { 1 } else { 0 }; |
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+ |
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+while micros > 0 { |
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+let st = if micros > MAX_MICROS as u128 { MAX_MICROS } else { micros as u32 }; |
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+unsafe { |
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libc::usleep(st); |
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- |
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- micros -= st as u128; |
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} |
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+ |
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+ micros -= st as u128; |
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} |
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} |
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