predicates/path/
fc.rs

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1// Copyright (c) 2018 The predicates-rs Project Developers.
2//
3// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
4// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
5// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
6// option. This file may not be copied, modified, or distributed
7// except according to those terms.
8
9use std::fmt;
10use std::fs;
11use std::io::{self, Read};
12use std::path;
13
14use crate::reflection;
15use crate::Predicate;
16
17fn read_file(path: &path::Path) -> io::Result<Vec<u8>> {
18    let mut buffer = Vec::new();
19    fs::File::open(path)?.read_to_end(&mut buffer)?;
20    Ok(buffer)
21}
22
23/// Predicate adapter that converts a `path` predicate to a byte predicate on its content.
24///
25/// This is created by `pred.from_path()`.
26#[derive(Debug, Clone, Copy, PartialEq, Eq)]
27pub struct FileContentPredicate<P>
28where
29    P: Predicate<[u8]>,
30{
31    p: P,
32}
33
34impl<P> FileContentPredicate<P>
35where
36    P: Predicate<[u8]>,
37{
38    fn eval(&self, path: &path::Path) -> io::Result<bool> {
39        let buffer = read_file(path)?;
40        Ok(self.p.eval(&buffer))
41    }
42}
43
44impl<P> reflection::PredicateReflection for FileContentPredicate<P>
45where
46    P: Predicate<[u8]>,
47{
48    fn children<'a>(&'a self) -> Box<dyn Iterator<Item = reflection::Child<'a>> + 'a> {
49        let params = vec![reflection::Child::new("predicate", &self.p)];
50        Box::new(params.into_iter())
51    }
52}
53
54impl<P> fmt::Display for FileContentPredicate<P>
55where
56    P: Predicate<[u8]>,
57{
58    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
59        self.p.fmt(f)
60    }
61}
62
63impl<P> Predicate<path::Path> for FileContentPredicate<P>
64where
65    P: Predicate<[u8]>,
66{
67    fn eval(&self, path: &path::Path) -> bool {
68        self.eval(path).unwrap_or(false)
69    }
70
71    fn find_case<'a>(
72        &'a self,
73        expected: bool,
74        variable: &path::Path,
75    ) -> Option<reflection::Case<'a>> {
76        let buffer = read_file(variable);
77        match (expected, buffer) {
78            (_, Ok(buffer)) => self.p.find_case(expected, &buffer).map(|case| {
79                case.add_product(reflection::Product::new(
80                    "var",
81                    variable.display().to_string(),
82                ))
83            }),
84            (true, Err(_)) => None,
85            (false, Err(err)) => Some(
86                reflection::Case::new(Some(self), false)
87                    .add_product(reflection::Product::new(
88                        "var",
89                        variable.display().to_string(),
90                    ))
91                    .add_product(reflection::Product::new("error", err)),
92            ),
93        }
94    }
95}
96
97/// `Predicate` extension adapting a `slice` Predicate.
98pub trait PredicateFileContentExt
99where
100    Self: Predicate<[u8]>,
101    Self: Sized,
102{
103    /// Returns a `FileContentPredicate` that adapts `Self` to a file content `Predicate`.
104    ///
105    /// # Examples
106    ///
107    /// ```
108    /// use predicates::prelude::*;
109    /// use std::path::Path;
110    ///
111    /// let predicate_fn = predicate::str::is_empty().not().from_utf8().from_file_path();
112    /// assert_eq!(true, predicate_fn.eval(Path::new("./tests/hello_world")));
113    /// assert_eq!(false, predicate_fn.eval(Path::new("./tests/empty_file")));
114    /// ```
115    #[allow(clippy::wrong_self_convention)]
116    fn from_file_path(self) -> FileContentPredicate<Self> {
117        FileContentPredicate { p: self }
118    }
119}
120
121impl<P> PredicateFileContentExt for P where P: Predicate<[u8]> {}
predicates/path/fc.rs

predicates/path/
fc.rs
