      1
      2
      3
      4
      5
      6
      7
      8
      9
     10
     11
     12
     13
     14
     15
     16
     17
     18
     19
     20
     21
     22
     23
     24
     25
     26
     27
     28
     29
     30
     31
     32
     33
     34
     35
     36
     37
     38
     39
     40
     41
     42
     43
     44
     45
     46
     47
     48
     49
     50
     51
     52
     53
     54
     55
     56
     57
     58
     59
     60
     61
     62
     63
     64
     65
     66
     67
     68
     69
     70
     71
     72
     73
     74
     75
     76
     77
     78
     79
     80
     81
     82
     83
     84
     85
     86
     87
     88
     89
     90
     91
     92
     93
     94
     95
     96
     97
     98
     99
    100
    101
    102
    103
    104
    105
    106
    107
    108
    109
    110
    111
    112
    113
    114
    115
    116
    117
    118
    119
    120
    121
    122
    123
    124
    125
    126
    127
    128
    129
    130
    131
    132
    133
    134
    135
    136
    137
    138
    139
    140
    141
    142
    143
    144
    145
    146
    147
    148
    149
    150

    //! Parallel iterator types for [vectors][std::vec] (`Vec<T>`)
    //!
    //! You will rarely need to interact with this module directly unless you need
    //! to name one of the iterator types.
    //!
    //! [std::vec]: https://doc.rust-lang.org/stable/std/vec/

    use iter::plumbing::*;
    use iter::*;
    use std;

    /// Parallel iterator that moves out of a vector.
    #[derive(Debug, Clone)]
    pub struct IntoIter<T: Send> {
        vec: Vec<T>,
    }

    impl<T: Send> IntoParallelIterator for Vec<T> {
        type Item = T;
        type Iter = IntoIter<T>;

        fn into_par_iter(self) -> Self::Iter {
            IntoIter { vec: self }
        }
    }

    impl<T: Send> ParallelIterator for IntoIter<T> {
        type Item = T;

        fn drive_unindexed<C>(self, consumer: C) -> C::Result
        where
            C: UnindexedConsumer<Self::Item>,
        {
            bridge(self, consumer)
        }

        fn opt_len(&self) -> Option<usize> {
            Some(self.len())
        }
    }

    impl<T: Send> IndexedParallelIterator for IntoIter<T> {
        fn drive<C>(self, consumer: C) -> C::Result
        where
            C: Consumer<Self::Item>,
        {
            bridge(self, consumer)
        }

        fn len(&self) -> usize {
            self.vec.len()
        }

        fn with_producer<CB>(mut self, callback: CB) -> CB::Output
        where
            CB: ProducerCallback<Self::Item>,
        {
            // The producer will move or drop each item from its slice, effectively taking ownership of
            // them.  When we're done, the vector only needs to free its buffer.
            unsafe {
                // Make the vector forget about the actual items.
                let len = self.vec.len();
                self.vec.set_len(0);

                // Get a correct borrow, then extend it to the original length.
                let mut slice = self.vec.as_mut_slice();
                slice = std::slice::from_raw_parts_mut(slice.as_mut_ptr(), len);

                callback.callback(VecProducer { slice })
            }
        }
    }

    /// ////////////////////////////////////////////////////////////////////////

    struct VecProducer<'data, T: 'data + Send> {
        slice: &'data mut [T],
    }

    impl<'data, T: 'data + Send> Producer for VecProducer<'data, T> {
        type Item = T;
        type IntoIter = SliceDrain<'data, T>;

        fn into_iter(mut self) -> Self::IntoIter {
            // replace the slice so we don't drop it twice
            let slice = std::mem::replace(&mut self.slice, &mut []);
            SliceDrain {
                iter: slice.iter_mut(),
            }
        }

        fn split_at(mut self, index: usize) -> (Self, Self) {
            // replace the slice so we don't drop it twice
            let slice = std::mem::replace(&mut self.slice, &mut []);
            let (left, right) = slice.split_at_mut(index);
            (VecProducer { slice: left }, VecProducer { slice: right })
        }
    }

    impl<'data, T: 'data + Send> Drop for VecProducer<'data, T> {
        fn drop(&mut self) {
            SliceDrain {
                iter: self.slice.iter_mut(),
            };
        }
    }

    /// ////////////////////////////////////////////////////////////////////////

    // like std::vec::Drain, without updating a source Vec
    struct SliceDrain<'data, T: 'data> {
        iter: std::slice::IterMut<'data, T>,
    }

    impl<'data, T: 'data> Iterator for SliceDrain<'data, T> {
        type Item = T;

        fn next(&mut self) -> Option<T> {
            let ptr = self.iter.next()?;
            Some(unsafe { std::ptr::read(ptr) })
        }

        fn size_hint(&self) -> (usize, Option<usize>) {
            let len = self.len();
            (len, Some(len))
        }
    }

    impl<'data, T: 'data> DoubleEndedIterator for SliceDrain<'data, T> {
        fn next_back(&mut self) -> Option<Self::Item> {
            let ptr = self.iter.next_back()?;
            Some(unsafe { std::ptr::read(ptr) })
        }
    }

    impl<'data, T: 'data> ExactSizeIterator for SliceDrain<'data, T> {
        fn len(&self) -> usize {
            self.iter.len()
        }
    }

    impl<'data, T: 'data> Drop for SliceDrain<'data, T> {
        fn drop(&mut self) {
            for ptr in &mut self.iter {
                unsafe {
                    std::ptr::drop_in_place(ptr);
                }
            }
        }
    }

# Help

## Keyboard Shortcuts

`?`
  Show this help dialog
`S`
  Focus the search field
`↑`
  Move up in search results
`↓`
  Move down in search results
`↹`
  Switch tab
`⏎`
  Go to active search result
`+`
  Expand all sections
`-`
  Collapse all sections

## Search Tricks

Prefix searches with a type followed by a colon (e.g., `fn:`) to restrict the search to a given type.

Accepted types are: `fn`, `mod`, `struct`, `enum`, `trait`, `type`, `macro`, and `const`.

Search functions by type signature (e.g., `vec -> usize` or `* -> vec`)

Search multiple things at once by splitting your query with comma (e.g., `str,u8` or `String,struct:Vec,test`)