diff options
Diffstat (limited to 'clippy_lints/src/module_style.rs')
| -rw-r--r-- | clippy_lints/src/module_style.rs | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/clippy_lints/src/module_style.rs b/clippy_lints/src/module_style.rs new file mode 100644 index 00000000000..73e93cf5a3e --- /dev/null +++ b/clippy_lints/src/module_style.rs @@ -0,0 +1,178 @@ +use std::{ + ffi::OsString, + path::{Component, Path}, +}; + +use rustc_ast::ast; +use rustc_data_structures::fx::{FxHashMap, FxHashSet}; +use rustc_lint::{EarlyContext, EarlyLintPass, Level, LintContext}; +use rustc_session::{declare_tool_lint, impl_lint_pass}; +use rustc_span::{FileName, RealFileName, SourceFile, Span, SyntaxContext}; + +declare_clippy_lint! { + /// ### What it does + /// Checks that module layout uses only self named module files, bans mod.rs files. + /// + /// ### Why is this bad? + /// Having multiple module layout styles in a project can be confusing. + /// + /// ### Example + /// ```text + /// src/ + /// stuff/ + /// stuff_files.rs + /// mod.rs + /// lib.rs + /// ``` + /// Use instead: + /// ```text + /// src/ + /// stuff/ + /// stuff_files.rs + /// stuff.rs + /// lib.rs + /// ``` + pub MOD_MODULE_FILES, + restriction, + "checks that module layout is consistent" +} + +declare_clippy_lint! { + /// ### What it does + /// Checks that module layout uses only mod.rs files. + /// + /// ### Why is this bad? + /// Having multiple module layout styles in a project can be confusing. + /// + /// ### Example + /// ```text + /// src/ + /// stuff/ + /// stuff_files.rs + /// stuff.rs + /// lib.rs + /// ``` + /// Use instead: + /// ```text + /// src/ + /// stuff/ + /// stuff_files.rs + /// mod.rs + /// lib.rs + /// ``` + + pub SELF_NAMED_MODULE_FILES, + restriction, + "checks that module layout is consistent" +} + +pub struct ModStyle; + +impl_lint_pass!(ModStyle => [MOD_MODULE_FILES, SELF_NAMED_MODULE_FILES]); + +impl EarlyLintPass for ModStyle { + fn check_crate(&mut self, cx: &EarlyContext<'_>, _: &ast::Crate) { + if cx.builder.lint_level(MOD_MODULE_FILES).0 == Level::Allow + && cx.builder.lint_level(SELF_NAMED_MODULE_FILES).0 == Level::Allow + { + return; + } + + let files = cx.sess.source_map().files(); + + let trim_to_src = if let RealFileName::LocalPath(p) = &cx.sess.working_dir { + p.to_string_lossy() + } else { + return; + }; + + // `folder_segments` is all unique folder path segments `path/to/foo.rs` gives + // `[path, to]` but not foo + let mut folder_segments = FxHashSet::default(); + // `mod_folders` is all the unique folder names that contain a mod.rs file + let mut mod_folders = FxHashSet::default(); + // `file_map` maps file names to the full path including the file name + // `{ foo => path/to/foo.rs, .. } + let mut file_map = FxHashMap::default(); + for file in files.iter() { + match &file.name { + FileName::Real(RealFileName::LocalPath(lp)) + if lp.to_string_lossy().starts_with(trim_to_src.as_ref()) => + { + let p = lp.to_string_lossy(); + let path = Path::new(p.trim_start_matches(trim_to_src.as_ref())); + if let Some(stem) = path.file_stem() { + file_map.insert(stem.to_os_string(), (file, path.to_owned())); + } + process_paths_for_mod_files(path, &mut folder_segments, &mut mod_folders); + check_self_named_mod_exists(cx, path, file); + } + _ => {}, + } + } + + for folder in &folder_segments { + if !mod_folders.contains(folder) { + if let Some((file, path)) = file_map.get(folder) { + let mut correct = path.clone(); + correct.pop(); + correct.push(folder); + correct.push("mod.rs"); + cx.struct_span_lint( + SELF_NAMED_MODULE_FILES, + Span::new(file.start_pos, file.start_pos, SyntaxContext::root()), + |build| { + let mut lint = + build.build(&format!("`mod.rs` files are required, found `{}`", path.display())); + lint.help(&format!("move `{}` to `{}`", path.display(), correct.display(),)); + lint.emit(); + }, + ); + } + } + } + } +} + +/// For each `path` we add each folder component to `folder_segments` and if the file name +/// is `mod.rs` we add it's parent folder to `mod_folders`. +fn process_paths_for_mod_files( + path: &Path, + folder_segments: &mut FxHashSet<OsString>, + mod_folders: &mut FxHashSet<OsString>, +) { + let mut comp = path.components().rev().peekable(); + let _ = comp.next(); + if path.ends_with("mod.rs") { + mod_folders.insert(comp.peek().map(|c| c.as_os_str().to_owned()).unwrap_or_default()); + } + let folders = comp + .filter_map(|c| { + if let Component::Normal(s) = c { + Some(s.to_os_string()) + } else { + None + } + }) + .collect::<Vec<_>>(); + folder_segments.extend(folders); +} + +/// Checks every path for the presence of `mod.rs` files and emits the lint if found. +fn check_self_named_mod_exists(cx: &EarlyContext<'_>, path: &Path, file: &SourceFile) { + if path.ends_with("mod.rs") { + let mut mod_file = path.to_path_buf(); + mod_file.pop(); + mod_file.set_extension("rs"); + + cx.struct_span_lint( + MOD_MODULE_FILES, + Span::new(file.start_pos, file.start_pos, SyntaxContext::root()), + |build| { + let mut lint = build.build(&format!("`mod.rs` files are not allowed, found `{}`", path.display())); + lint.help(&format!("move `{}` to `{}`", path.display(), mod_file.display(),)); + lint.emit(); + }, + ); + } +} |