~matthiasbeyer/imag

ref: be50f5ad51d05dd3d24ecfd6343055737a2757f0 imag/lib/entry/libimagentryview/src/viewer.rs -rw-r--r-- 4.0 KiB
be50f5adMatthias Beyer builds: nixos: Switch to latest stable channel 1 year, 5 months ago
                                                                                                    
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
151
152
153
//
// imag - the personal information management suite for the commandline
// Copyright (C) 2015-2020 Matthias Beyer <mail@beyermatthias.de> and contributors
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; version
// 2.1 of the License.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
//

use std::io::Write;
use std::ops::Deref;

use libimagstore::store::Entry;
use libimagstore::store::FileLockEntry;

use anyhow::Result;

pub trait Viewer {

    fn view_entry<W>(&self, e: &Entry, sink: &mut W) -> Result<()>
        where W: Write;

    fn view_entries<I, E, W>(&self, entries: I, sink: &mut W) -> Result<()>
        where I: Iterator<Item = E>,
              E: Deref<Target = Entry>,
              W: Write
    {
        for entry in entries {
            self.view_entry(entry.deref(), sink)?;
        }
        Ok(())
    }
}

/// Extension for all iterators, so that an iterator can be viewed with:
///
/// ```ignore
///     iter.view::<Viewer, _>(&mut sink)
/// ```
///
pub trait ViewFromIter {
    fn view<V, W>(self, sink: &mut W) -> Result<()>
        where V: Viewer + Default,
              W: Write;

    fn view_with<V, W>(self, v: V, sink: &mut W) -> Result<()>
        where V: Viewer,
              W: Write;
}

impl<I, E> ViewFromIter for I
    where I: Iterator<Item = E>,
          E: Deref<Target = Entry>
{
    fn view<V, W>(self, sink: &mut W) -> Result<()>
        where V: Viewer + Default,
              W: Write
    {
        self.view_with(V::default(), sink)
    }

    fn view_with<V, W>(self, v: V, sink: &mut W) -> Result<()>
        where V: Viewer,
              W: Write
    {
        v.view_entries(self, sink)
    }
}

pub trait IntoViewIter<V, W, F, T>
    where Self: Iterator<Item = T> + Sized,
          V: Viewer,
          W: Write,
          F: Fn(&T) -> Option<&FileLockEntry>,
          T: Sized,
{
    fn view_all_if(self, v: V, sink: &mut W, func: F) -> ViewIter<Self, V, W, F, T> {
        ViewIter {
            inner: self,
            viewer: v,
            func,
            sink,
        }
    }
}

impl<I, V, W, F, T> IntoViewIter<V, W, F, T> for I
    where I: Iterator<Item = T>,
          V: Viewer,
          W: Write,
          F: Fn(&T) -> Option<&FileLockEntry>,
          T: Sized,
{
    // default impl
}


pub struct ViewIter<'a, I, V, W, F, T>
    where I: Iterator<Item = T>,
          V: Viewer,
          W: Write,
          F: Fn(&T) -> Option<&FileLockEntry>,
          T: Sized,
{
    inner: I,
    viewer: V,
    func: F,
    sink: &'a mut W
}

impl<'a, I, V, W, F, T> Iterator for ViewIter<'a, I, V, W, F, T>
    where I: Iterator<Item = T>,
          V: Viewer,
          W: Write,
          F: Fn(&T) -> Option<&FileLockEntry>,
          T: Sized,
{
    type Item = Result<T>;

    fn next(&mut self) -> Option<Self::Item> {
        if let Some(next) = self.inner.next() {
            if let Some(entry) = (self.func)(&next) {
                let r = self.viewer.view_entry(&entry, self.sink);
                trace!("Viewing resulted in {:?}", r);
                if let Err(e) = r {
                    if let Some(ioerr) = e.downcast_ref::<::std::io::Error>() {
                        if ioerr.kind() == ::std::io::ErrorKind::BrokenPipe {
                            trace!("Stopping iteration, because of broken pipe error!");
                            return None
                        }
                    }

                    return Some(Err(e))
                }
            }

            return Some(Ok(next))
        }

        None
    }
}