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]> {}
122