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

// conn_expr/resolution.rs
// Copyright 2022 Matti Hänninen
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.

use std::{fs, io, path, thread, time};

use crate::error::Error;

use super::conn_expr::ConnectionExpr;

#[derive(Debug)]
pub enum ConnectionExprSource {
  /// Use this connection expression.
  Direct(ConnectionExpr),
  /// Read the connection expression from the port file.
  PortFile {
    /// Use this instead of the nearest .nrepl-port file.
    path: Option<path::PathBuf>,
    /// If not available, give it this amount of time to appear.
    wait_for: Option<time::Duration>,
  },
}

impl From<ConnectionExpr> for ConnectionExprSource {
  fn from(e: ConnectionExpr) -> Self {
    ConnectionExprSource::Direct(e)
  }
}

impl From<&ConnectionExpr> for ConnectionExprSource {
  fn from(e: &ConnectionExpr) -> Self {
    e.clone().into()
  }
}

impl ConnectionExprSource {
  pub fn resolve_expr(&self) -> Result<ConnectionExpr, Error> {
    const THROTTLING_DELAY: time::Duration = time::Duration::from_millis(50);
    match self {
      ConnectionExprSource::Direct(e) => Ok(e.clone()),
      ConnectionExprSource::PortFile {
        path,
        wait_for: None,
      } => try_load_from_port_file(path.as_ref()),
      ConnectionExprSource::PortFile {
        path,
        wait_for: Some(duration),
      } => {
        let deadline = time::SystemTime::now() + *duration;
        loop {
          match try_load_from_port_file(path.as_ref()) {
            Ok(r) => return Ok(r),
            Err(e) => match e {
              Error::NotSpecified | Error::NotFound(_) => {
                if time::SystemTime::now() >= deadline {
                  return Err(Error::PortFileTimeout);
                }
              }
              _ => return Err(e),
            },
          }
          thread::sleep(THROTTLING_DELAY);
        }
      }
    }
  }
}

fn try_load_from_port_file(
  given: Option<impl AsRef<path::Path>>,
) -> Result<ConnectionExpr, Error> {
  if let Some(f) = given {
    load_from_port_file(f)
  } else if let Some(ref f) = find_port_file().map_err(|_| Error::Unknown)? {
    load_from_port_file(f)
  } else {
    Err(Error::NotSpecified)
  }
}

fn find_port_file() -> io::Result<Option<path::PathBuf>> {
  let current_dir = path::PathBuf::from(".").canonicalize()?;
  for dir in current_dir.ancestors() {
    let mut path = path::PathBuf::from(dir);
    path.push(".nrepl-port");
    if path.is_file() {
      return Ok(Some(path));
    }
  }
  Ok(None)
}

fn load_from_port_file(
  path: impl AsRef<path::Path>,
) -> Result<ConnectionExpr, Error> {
  let path = path.as_ref();
  fs::read_to_string(path)
    .map_err(|e| {
      if e.kind() == io::ErrorKind::NotFound {
        Error::NotFound(path.to_string_lossy().into())
      } else {
        Error::CannotReadFile(path.to_string_lossy().into())
      }
    })?
    .trim()
    .parse()
    .map_err(|_| Error::CannotParsePortFile(path.to_string_lossy().into()))
}