311 lines
11 KiB
Rust
311 lines
11 KiB
Rust
use rustc::lint::*;
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use rustc_front::hir::*;
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use reexport::*;
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use syntax::codemap::{ExpnInfo, Span, ExpnFormat};
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use rustc::front::map::Node::*;
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use rustc::middle::def_id::DefId;
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use rustc::middle::ty;
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use std::borrow::Cow;
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use syntax::ast::Lit_::*;
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// module DefPaths for certain structs/enums we check for
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pub const OPTION_PATH: [&'static str; 3] = ["core", "option", "Option"];
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pub const RESULT_PATH: [&'static str; 3] = ["core", "result", "Result"];
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pub const STRING_PATH: [&'static str; 3] = ["collections", "string", "String"];
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pub const VEC_PATH: [&'static str; 3] = ["collections", "vec", "Vec"];
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pub const LL_PATH: [&'static str; 3] = ["collections", "linked_list", "LinkedList"];
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/// returns true this expn_info was expanded by any macro
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pub fn in_macro(cx: &LateContext, span: Span) -> bool {
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cx.sess().codemap().with_expn_info(span.expn_id,
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|info| info.map_or(false, |i| {
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match i.callee.format {
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ExpnFormat::CompilerExpansion(..) => false,
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_ => true,
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}
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}))
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}
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/// returns true if the macro that expanded the crate was outside of
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/// the current crate or was a compiler plugin
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pub fn in_external_macro<T: LintContext>(cx: &T, span: Span) -> bool {
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/// invokes in_macro with the expansion info of the given span
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/// slightly heavy, try to use this after other checks have already happened
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fn in_macro_ext<T: LintContext>(cx: &T, opt_info: Option<&ExpnInfo>) -> bool {
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// no ExpnInfo = no macro
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opt_info.map_or(false, |info| {
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match info.callee.format {
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ExpnFormat::CompilerExpansion(..) => {
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if info.callee.name().as_str() == "closure expansion" {
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return false;
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}
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},
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ExpnFormat::MacroAttribute(..) => {
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// these are all plugins
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return true;
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},
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_ => (),
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}
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// no span for the callee = external macro
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info.callee.span.map_or(true, |span| {
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// no snippet = external macro or compiler-builtin expansion
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cx.sess().codemap().span_to_snippet(span).ok().map_or(true, |code|
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// macro doesn't start with "macro_rules"
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// = compiler plugin
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!code.starts_with("macro_rules")
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)
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})
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})
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}
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cx.sess().codemap().with_expn_info(span.expn_id,
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|info| in_macro_ext(cx, info))
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}
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/// check if a DefId's path matches the given absolute type path
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/// usage e.g. with
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/// `match_def_path(cx, id, &["core", "option", "Option"])`
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pub fn match_def_path(cx: &LateContext, def_id: DefId, path: &[&str]) -> bool {
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cx.tcx.with_path(def_id, |iter| iter.zip(path)
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.all(|(nm, p)| nm.name().as_str() == *p))
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}
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/// check if type is struct or enum type with given def path
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pub fn match_type(cx: &LateContext, ty: ty::Ty, path: &[&str]) -> bool {
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match ty.sty {
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ty::TyEnum(ref adt, _) | ty::TyStruct(ref adt, _) => {
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match_def_path(cx, adt.did, path)
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}
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_ => {
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false
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}
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}
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}
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/// check if method call given in "expr" belongs to given trait
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pub fn match_trait_method(cx: &LateContext, expr: &Expr, path: &[&str]) -> bool {
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let method_call = ty::MethodCall::expr(expr.id);
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let trt_id = cx.tcx.tables
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.borrow().method_map.get(&method_call)
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.and_then(|callee| cx.tcx.trait_of_item(callee.def_id));
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if let Some(trt_id) = trt_id {
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match_def_path(cx, trt_id, path)
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} else {
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false
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}
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}
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/// match a Path against a slice of segment string literals, e.g.
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/// `match_path(path, &["std", "rt", "begin_unwind"])`
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pub fn match_path(path: &Path, segments: &[&str]) -> bool {
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path.segments.iter().rev().zip(segments.iter().rev()).all(
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|(a, b)| a.identifier.name.as_str() == *b)
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}
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/// get the name of the item the expression is in, if available
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pub fn get_item_name(cx: &LateContext, expr: &Expr) -> Option<Name> {
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let parent_id = cx.tcx.map.get_parent(expr.id);
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match cx.tcx.map.find(parent_id) {
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Some(NodeItem(&Item{ ref name, .. })) |
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Some(NodeTraitItem(&TraitItem{ id: _, ref name, .. })) |
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Some(NodeImplItem(&ImplItem{ id: _, ref name, .. })) => {
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Some(*name)
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},
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_ => None,
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}
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}
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/// convert a span to a code snippet if available, otherwise use default, e.g.
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/// `snippet(cx, expr.span, "..")`
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pub fn snippet<'a, T: LintContext>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
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cx.sess().codemap().span_to_snippet(span).map(From::from).unwrap_or(Cow::Borrowed(default))
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}
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/// convert a span (from a block) to a code snippet if available, otherwise use default, e.g.
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/// `snippet(cx, expr.span, "..")`
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/// This trims the code of indentation, except for the first line
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/// Use it for blocks or block-like things which need to be printed as such
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pub fn snippet_block<'a, T: LintContext>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
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let snip = snippet(cx, span, default);
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trim_multiline(snip, true)
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}
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/// Like snippet_block, but add braces if the expr is not an ExprBlock
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/// Also takes an Option<String> which can be put inside the braces
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pub fn expr_block<'a, T: LintContext>(cx: &T, expr: &Expr,
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option: Option<String>,
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default: &'a str) -> Cow<'a, str> {
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let code = snippet_block(cx, expr.span, default);
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let string = option.map_or("".to_owned(), |s| s);
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if let ExprBlock(_) = expr.node {
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Cow::Owned(format!("{}{}", code, string))
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} else if string.is_empty() {
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Cow::Owned(format!("{{ {} }}", code))
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} else {
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Cow::Owned(format!("{{\n{};\n{}\n}}", code, string))
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}
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}
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/// Trim indentation from a multiline string
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/// with possibility of ignoring the first line
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pub fn trim_multiline(s: Cow<str>, ignore_first: bool) -> Cow<str> {
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let s_space = trim_multiline_inner(s, ignore_first, ' ');
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let s_tab = trim_multiline_inner(s_space, ignore_first, '\t');
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trim_multiline_inner(s_tab, ignore_first, ' ')
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}
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fn trim_multiline_inner(s: Cow<str>, ignore_first: bool, ch: char) -> Cow<str> {
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let x = s.lines().skip(ignore_first as usize)
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.filter_map(|l| { if l.len() > 0 { // ignore empty lines
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Some(l.char_indices()
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.find(|&(_,x)| x != ch)
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.unwrap_or((l.len(), ch)).0)
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} else {None}})
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.min().unwrap_or(0);
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if x > 0 {
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Cow::Owned(s.lines().enumerate().map(|(i,l)| if (ignore_first && i == 0) ||
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l.len() == 0 {
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l
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} else {
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l.split_at(x).1
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}).collect::<Vec<_>>()
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.join("\n"))
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} else {
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s
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}
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}
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/// get a parent expr if any – this is useful to constrain a lint
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pub fn get_parent_expr<'c>(cx: &'c LateContext, e: &Expr) -> Option<&'c Expr> {
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let map = &cx.tcx.map;
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let node_id : NodeId = e.id;
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let parent_id : NodeId = map.get_parent_node(node_id);
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if node_id == parent_id { return None; }
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map.find(parent_id).and_then(|node|
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if let NodeExpr(parent) = node { Some(parent) } else { None } )
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}
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#[cfg(not(feature="structured_logging"))]
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pub fn span_lint<T: LintContext>(cx: &T, lint: &'static Lint, sp: Span, msg: &str) {
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cx.span_lint(lint, sp, msg);
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if cx.current_level(lint) != Level::Allow {
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cx.sess().fileline_help(sp, &format!("for further information visit \
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https://github.com/Manishearth/rust-clippy/wiki#{}",
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lint.name_lower()))
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}
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}
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#[cfg(feature="structured_logging")]
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pub fn span_lint<T: LintContext>(cx: &T, lint: &'static Lint, sp: Span, msg: &str) {
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// lint.name / lint.desc is can give details of the lint
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// cx.sess().codemap() has all these nice functions for line/column/snippet details
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// http://doc.rust-lang.org/syntax/codemap/struct.CodeMap.html#method.span_to_string
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cx.span_lint(lint, sp, msg);
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if cx.current_level(lint) != Level::Allow {
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cx.sess().fileline_help(sp, &format!("for further information visit \
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https://github.com/Manishearth/rust-clippy/wiki#{}",
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lint.name_lower()))
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}
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}
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pub fn span_help_and_lint<T: LintContext>(cx: &T, lint: &'static Lint, span: Span,
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msg: &str, help: &str) {
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cx.span_lint(lint, span, msg);
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if cx.current_level(lint) != Level::Allow {
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cx.sess().fileline_help(span, &format!("{}\nfor further information \
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visit https://github.com/Manishearth/rust-clippy/wiki#{}",
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help, lint.name_lower()))
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}
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}
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pub fn span_note_and_lint<T: LintContext>(cx: &T, lint: &'static Lint, span: Span,
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msg: &str, note_span: Span, note: &str) {
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cx.span_lint(lint, span, msg);
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if cx.current_level(lint) != Level::Allow {
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if note_span == span {
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cx.sess().fileline_note(note_span, note)
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} else {
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cx.sess().span_note(note_span, note)
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}
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cx.sess().fileline_help(span, &format!("for further information visit \
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https://github.com/Manishearth/rust-clippy/wiki#{}",
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lint.name_lower()))
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}
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}
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/// return the base type for references and raw pointers
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pub fn walk_ptrs_ty(ty: ty::Ty) -> ty::Ty {
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match ty.sty {
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ty::TyRef(_, ref tm) | ty::TyRawPtr(ref tm) => walk_ptrs_ty(tm.ty),
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_ => ty
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}
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}
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/// return the base type for references and raw pointers, and count reference depth
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pub fn walk_ptrs_ty_depth(ty: ty::Ty) -> (ty::Ty, usize) {
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fn inner(ty: ty::Ty, depth: usize) -> (ty::Ty, usize) {
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match ty.sty {
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ty::TyRef(_, ref tm) | ty::TyRawPtr(ref tm) => inner(tm.ty, depth + 1),
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_ => (ty, depth)
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}
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}
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inner(ty, 0)
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}
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pub fn is_integer_literal(expr: &Expr, value: u64) -> bool
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{
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// FIXME: use constant folding
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if let ExprLit(ref spanned) = expr.node {
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if let LitInt(v, _) = spanned.node {
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return v == value;
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}
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}
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false
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}
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/// Produce a nested chain of if-lets and ifs from the patterns:
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///
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/// if_let_chain! {
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/// [
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/// Some(y) = x,
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/// y.len() == 2,
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/// Some(z) = y,
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/// ],
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/// {
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/// block
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/// }
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/// }
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///
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/// becomes
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///
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/// if let Some(y) = x {
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/// if y.len() == 2 {
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/// if let Some(z) = y {
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/// block
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/// }
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/// }
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/// }
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#[macro_export]
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macro_rules! if_let_chain {
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([let $pat:pat = $expr:expr, $($tt:tt)+], $block:block) => {
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if let $pat = $expr {
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if_let_chain!{ [$($tt)+], $block }
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}
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};
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([let $pat:pat = $expr:expr], $block:block) => {
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if let $pat = $expr {
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$block
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}
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};
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([$expr:expr, $($tt:tt)+], $block:block) => {
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if $expr {
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if_let_chain!{ [$($tt)+], $block }
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}
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};
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([$expr:expr], $block:block) => {
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if $expr {
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$block
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}
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};
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}
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