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

// Copyright (c) 2018 The predicates-rs Project Developers.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use std::fmt;
use std::fs;
use std::io::{self, Read};
use std::path;

use crate::reflection;
use crate::Predicate;

fn read_file(path: &path::Path) -> io::Result<Vec<u8>> {
    let mut buffer = Vec::new();
    fs::File::open(path)?.read_to_end(&mut buffer)?;
    Ok(buffer)
}

/// Predicate adapter that converts a `path` predicate to a byte predicate on its content.
///
/// This is created by `pred.from_path()`.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct FileContentPredicate<P>
where
    P: Predicate<[u8]>,
{
    p: P,
}

impl<P> FileContentPredicate<P>
where
    P: Predicate<[u8]>,
{
    fn eval(&self, path: &path::Path) -> io::Result<bool> {
        let buffer = read_file(path)?;
        Ok(self.p.eval(&buffer))
    }
}

impl<P> reflection::PredicateReflection for FileContentPredicate<P>
where
    P: Predicate<[u8]>,
{
    fn children<'a>(&'a self) -> Box<dyn Iterator<Item = reflection::Child<'a>> + 'a> {
        let params = vec![reflection::Child::new("predicate", &self.p)];
        Box::new(params.into_iter())
    }
}

impl<P> fmt::Display for FileContentPredicate<P>
where
    P: Predicate<[u8]>,
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{}", self.p)
    }
}

impl<P> Predicate<path::Path> for FileContentPredicate<P>
where
    P: Predicate<[u8]>,
{
    fn eval(&self, path: &path::Path) -> bool {
        self.eval(path).unwrap_or(false)
    }

    fn find_case<'a>(
        &'a self,
        expected: bool,
        variable: &path::Path,
    ) -> Option<reflection::Case<'a>> {
        let buffer = read_file(variable);
        match (expected, buffer) {
            (_, Ok(buffer)) => self
                .p
                .find_case(expected, &buffer)
                .map(|child| reflection::Case::new(Some(self), expected).add_child(child)),
            (true, Err(_)) => None,
            (false, Err(err)) => Some(
                reflection::Case::new(Some(self), false)
                    .add_product(reflection::Product::new("error", err)),
            ),
        }
    }
}

/// `Predicate` extension adapting a `slice` Predicate.
pub trait PredicateFileContentExt
where
    Self: Predicate<[u8]>,
    Self: Sized,
{
    /// Returns a `FileContentPredicate` that adapts `Self` to a file content `Predicate`.
    ///
    /// # Examples
    ///
    /// ```
    /// use predicates::prelude::*;
    /// use std::path::Path;
    ///
    /// let predicate_fn = predicate::str::is_empty().not().from_utf8().from_file_path();
    /// assert_eq!(true, predicate_fn.eval(Path::new("./tests/hello_world")));
    /// assert_eq!(false, predicate_fn.eval(Path::new("./tests/empty_file")));
    /// ```
    fn from_file_path(self) -> FileContentPredicate<Self> {
        FileContentPredicate { p: self }
    }
}

impl<P> PredicateFileContentExt for P where P: Predicate<[u8]> {}