libktx_rs_macros/
lib.rs

1// Copyright (C) 2021 Paolo Jovon <paolo.jovon@gmail.com>
2// SPDX-License-Identifier: Apache-2.0
3
4//! Utilities for testing [`libktx_rs`].
5//! a library for reading, transcoding and writing [Khronos Textures (KTX)](https://www.khronos.org/ktx/).
6
7use glob::glob;
8use proc_macro::TokenStream;
9use proc_macro2::Span;
10use quote::quote;
11use std::{collections::HashSet, iter::FromIterator, ops::Sub};
12use syn::{
13    self,
14    parse::{Parse, ParseStream, Result},
15    parse_macro_input,
16    punctuated::Punctuated,
17    Ident, LitStr, Path, Token,
18};
19
20struct GlobPattern {
21    inverted: bool,
22    pattern: LitStr,
23}
24
25impl Parse for GlobPattern {
26    fn parse(input: ParseStream) -> Result<Self> {
27        let inverted = input.parse::<Token![!]>().is_ok();
28        let pattern = input.parse()?;
29        Ok(GlobPattern { inverted, pattern })
30    }
31}
32
33type GlobPatternList = Punctuated<GlobPattern, Token![,]>;
34
35struct FileTestsInput {
36    test_fn: Path,
37    globs: GlobPatternList,
38}
39
40impl Parse for FileTestsInput {
41    fn parse(input: ParseStream) -> Result<Self> {
42        let test_fn: Path = input.parse()?;
43        input.parse::<Token![=>]>()?;
44        let globs: GlobPatternList = input.parse_terminated(GlobPattern::parse)?;
45        Ok(FileTestsInput { test_fn, globs })
46    }
47}
48
49fn glob_all<'a>(patterns: impl Iterator<Item = &'a GlobPattern>) -> HashSet<std::path::PathBuf> {
50    patterns
51        .filter_map(|pattern| glob(pattern.pattern.value().as_str()).ok())
52        .flat_map(|paths| paths.filter_map(|path| path.ok()))
53        .collect()
54}
55
56/// Collects a list of files at compile time (!), then generates a test case for each one of them.
57/// The test case will invoke a given function, passing it the [`std::path::PathBuf`] to it and the open [`std::fs::File`].
58///
59/// ```rust,ignore
60/// file_tests!(test_fn => "glob", !"glob", ...);
61/// ````
62/// For each file matching the given glob pattern\[s\] (at compile time!), generates a `#[test]` that invokes
63/// ```rust,ignore
64/// fn test_fn(file: std::fs::File);
65/// ````
66/// Globs preceded by `!` are inverted (matches are removed).
67#[proc_macro]
68pub fn file_tests(input: TokenStream) -> TokenStream {
69    let input = parse_macro_input!(input as FileTestsInput);
70
71    let glob_accepted = glob_all(input.globs.iter().filter(|pattern| !pattern.inverted));
72    let glob_rejected = glob_all(input.globs.iter().filter(|pattern| pattern.inverted));
73    let test_files = glob_accepted.sub(&glob_rejected);
74
75    let test_fn_name = input.test_fn.segments.last().unwrap().ident.to_string();
76
77    let fns_tokens = test_files.iter().enumerate().map(|(i, path)| {
78        let mut fn_name = path
79            .file_stem()
80            .map(|name| {
81                format!(
82                    "test{}_{}_{}",
83                    i,
84                    test_fn_name,
85                    name.to_str().expect("Invalid filename")
86                )
87            })
88            .expect("Invalid globbed path");
89        // Sanitize the identifier
90        fn_name = fn_name
91            .chars()
92            .map(|ch| match ch {
93                'A'..='Z' | 'a'..='z' | '0'..='9' => ch,
94                _ => '_',
95            })
96            .collect();
97
98        let test_fn = &input.test_fn;
99        let abs_path = path.canonicalize().expect("Could not make absolute path");
100        let path_str = abs_path.to_str().expect("Invalid path");
101        let fn_ident = Ident::new(fn_name.as_str(), Span::call_site());
102
103        quote! {
104            #[test]
105            fn #fn_ident() {
106                let path = std::path::PathBuf::from(#path_str);
107                println!("Test file: {}", #path_str);
108                match std::fs::File::open(&path) {
109                    Ok(file) => #test_fn(path, file),
110                    Err(err) => panic!("Error loading test file: {}: {}", #path_str, err),
111                }
112            }
113        }
114    });
115
116    proc_macro2::TokenStream::from_iter(fns_tokens).into()
117}
libktx_rs_macros/lib.rs

libktx_rs_macros/
lib.rs
