integration-tests/tests/code_checkers.rs

// Copyright 2021 Google LLC
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use std::{
    fs::File,
    io::{BufRead, BufReader},
    path::PathBuf,
};

use itertools::{Either, Itertools};
use proc_macro2::TokenStream;
use quote::ToTokens;
use syn::Item;

use autocxx_integration_tests::{CodeChecker, CodeCheckerFns, TestError};

/// Generates a closure which can be used to ensure that the given symbol
/// is mentioned in the output and has documentation attached.
/// The idea is that this is what we do in cases where we can't generate code properly.
pub(crate) fn make_error_finder(error_symbol: &'static str) -> CodeChecker {
    Box::new(ErrorFinder(error_symbol))
}
struct ErrorFinder(&'static str);

impl CodeCheckerFns for ErrorFinder {
    fn check_rust(&self, rs: syn::File) -> Result<(), TestError> {
        let ffi_items = find_ffi_items(rs)?;
        // Ensure there's some kind of struct entry for this symbol
        let error_item = ffi_items
            .into_iter()
            .filter_map(|i| match i {
                Item::Struct(its) if its.ident == self.0 => Some(its),
                _ => None,
            })
            .next()
            .ok_or_else(|| TestError::RsCodeExaminationFail("Couldn't find item".into()))?;
        // Ensure doc attribute
        error_item
            .attrs
            .into_iter()
            .find(|a| a.path.get_ident().filter(|p| *p == "doc").is_some())
            .ok_or_else(|| TestError::RsCodeExaminationFail("Item had no docs".into()))?;
        Ok(())
    }
}

fn find_ffi_items(f: syn::File) -> Result<Vec<Item>, TestError> {
    let md = f
        .items
        .into_iter()
        .filter_map(|i| match i {
            Item::Mod(itm) => Some(itm),
            _ => None,
        })
        .next()
        .ok_or_else(|| TestError::RsCodeExaminationFail("No mods in file".into()))?;
    let mut items = Vec::new();
    find_all_non_mod_items(md, &mut items);
    Ok(items)
}

fn find_all_non_mod_items(md: syn::ItemMod, items: &mut Vec<Item>) {
    let (more_mods, mut these_items): (Vec<_>, Vec<_>) = md
        .content
        .into_iter()
        .flat_map(|(_, more_items)| more_items.into_iter())
        .partition_map(|i| match i {
            Item::Mod(itm) => Either::Left(itm),
            _ => Either::Right(i),
        });
    items.append(&mut these_items);
    for md in more_mods.into_iter() {
        find_all_non_mod_items(md, items);
    }
}

struct StringFinder(Vec<String>);

impl CodeCheckerFns for StringFinder {
    fn check_rust(&self, rs: syn::File) -> Result<(), TestError> {
        let toks = rs.to_token_stream().to_string();
        for msg in &self.0 {
            if !toks.contains(msg) {
                return Err(TestError::RsCodeExaminationFail(format!(
                    "Couldn't find string '{msg}'"
                )));
            };
        }
        Ok(())
    }
}

/// Returns a code checker which simply hunts for a given string in the results
pub(crate) fn make_string_finder(error_texts: Vec<String>) -> CodeChecker {
    Box::new(StringFinder(error_texts))
}

struct RustCodeFinder(Vec<TokenStream>);

impl CodeCheckerFns for RustCodeFinder {
    fn check_rust(&self, rs: syn::File) -> Result<(), TestError> {
        let haystack = rs.to_token_stream().to_string();
        for msg in &self.0 {
            let needle = msg.to_string();
            if !haystack.contains(&needle) {
                return Err(TestError::RsCodeExaminationFail(format!(
                    "Couldn't find tokens '{needle}'"
                )));
            };
        }
        Ok(())
    }
}

/// Returns a code checker which hunts for the given Rust tokens in the output
pub(crate) fn make_rust_code_finder(code: Vec<TokenStream>) -> CodeChecker {
    Box::new(RustCodeFinder(code))
}

/// Searches generated C++ for strings we want to find, or want _not_ to find,
/// or both.
pub(crate) struct CppMatcher<'a> {
    positive_matches: &'a [&'a str],
    negative_matches: &'a [&'a str],
}

impl<'a> CppMatcher<'a> {
    pub(crate) fn new(positive_matches: &'a [&'a str], negative_matches: &'a [&'a str]) -> Self {
        Self {
            positive_matches,
            negative_matches,
        }
    }
}

impl<'a> CodeCheckerFns for CppMatcher<'a> {
    fn check_cpp(&self, cpp: &[PathBuf]) -> Result<(), TestError> {
        let mut positives_needed = self.positive_matches.to_vec();
        for filename in cpp {
            let file = File::open(filename).unwrap();
            let lines = BufReader::new(file).lines();
            for l in lines.map_while(Result::ok) {
                if self.negative_matches.iter().any(|neg| l.contains(neg)) {
                    return Err(TestError::CppCodeExaminationFail);
                }
                positives_needed.retain(|pos| !l.contains(pos));
            }
        }
        if positives_needed.is_empty() {
            Ok(())
        } else {
            Err(TestError::CppCodeExaminationFail)
        }
    }
}

pub(crate) struct NoSystemHeadersChecker;

impl CodeCheckerFns for NoSystemHeadersChecker {
    fn check_cpp(&self, cpp: &[PathBuf]) -> Result<(), TestError> {
        for filename in cpp {
            let file = File::open(filename).unwrap();
            if BufReader::new(file)
                .lines()
                .any(|l| l.as_ref().unwrap().starts_with("#include <"))
            {
                return Err(TestError::CppCodeExaminationFail);
            }
        }
        Ok(())
    }
    fn skip_build(&self) -> bool {
        true
    }
}