Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/hir-expand/src/cfg_process.rs')
| -rw-r--r-- | crates/hir-expand/src/cfg_process.rs | 327 |
1 files changed, 327 insertions, 0 deletions
diff --git a/crates/hir-expand/src/cfg_process.rs b/crates/hir-expand/src/cfg_process.rs new file mode 100644 index 0000000000..c74c13a6fd --- /dev/null +++ b/crates/hir-expand/src/cfg_process.rs @@ -0,0 +1,327 @@ +//! Processes out #[cfg] and #[cfg_attr] attributes from the input for the derive macro +use std::iter::Peekable; + +use cfg::{CfgAtom, CfgExpr}; +use rustc_hash::FxHashSet; +use syntax::{ + ast::{self, Attr, HasAttrs, Meta, VariantList}, + AstNode, NodeOrToken, SyntaxElement, SyntaxNode, T, +}; +use tracing::{debug, warn}; +use tt::SmolStr; + +use crate::{db::ExpandDatabase, MacroCallKind, MacroCallLoc}; + +fn check_cfg_attr(attr: &Attr, loc: &MacroCallLoc, db: &dyn ExpandDatabase) -> Option<bool> { + if !attr.simple_name().as_deref().map(|v| v == "cfg")? { + return None; + } + debug!("Evaluating cfg {}", attr); + let cfg = parse_from_attr_meta(attr.meta()?)?; + debug!("Checking cfg {:?}", cfg); + let enabled = db.crate_graph()[loc.krate].cfg_options.check(&cfg) != Some(false); + Some(enabled) +} + +fn check_cfg_attr_attr(attr: &Attr, loc: &MacroCallLoc, db: &dyn ExpandDatabase) -> Option<bool> { + if !attr.simple_name().as_deref().map(|v| v == "cfg_attr")? { + return None; + } + debug!("Evaluating cfg_attr {}", attr); + let cfg_expr = parse_from_attr_meta(attr.meta()?)?; + debug!("Checking cfg_attr {:?}", cfg_expr); + let enabled = db.crate_graph()[loc.krate].cfg_options.check(&cfg_expr) != Some(false); + Some(enabled) +} + +fn process_has_attrs_with_possible_comma<I: HasAttrs>( + items: impl Iterator<Item = I>, + loc: &MacroCallLoc, + db: &dyn ExpandDatabase, + remove: &mut FxHashSet<SyntaxElement>, +) -> Option<()> { + for item in items { + let field_attrs = item.attrs(); + 'attrs: for attr in field_attrs { + if check_cfg_attr(&attr, loc, db).map(|enabled| !enabled).unwrap_or_default() { + debug!("censoring type {:?}", item.syntax()); + remove.insert(item.syntax().clone().into()); + // We need to remove the , as well + remove_possible_comma(&item, remove); + break 'attrs; + } + + if let Some(enabled) = check_cfg_attr_attr(&attr, loc, db) { + if enabled { + debug!("Removing cfg_attr tokens {:?}", attr); + let meta = attr.meta()?; + let removes_from_cfg_attr = remove_tokens_within_cfg_attr(meta)?; + remove.extend(removes_from_cfg_attr); + } else { + debug!("censoring type cfg_attr {:?}", item.syntax()); + remove.insert(attr.syntax().clone().into()); + continue; + } + } + } + } + Some(()) +} +#[derive(Debug, PartialEq, Eq, Clone, Copy)] +enum CfgExprStage { + /// Stripping the CFGExpr part of the attribute + StrippigCfgExpr, + /// Found the comma after the CFGExpr. Will keep all tokens until the next comma or the end of the attribute + FoundComma, + /// Everything following the attribute. This could be another attribute or the end of the attribute. + // FIXME: cfg_attr with multiple attributes will not be handled correctly. We will only keep the first attribute + // Related Issue: https://github.com/rust-lang/rust-analyzer/issues/10110 + EverythingElse, +} +/// This function creates its own set of tokens to remove. To help prevent malformed syntax as input. +fn remove_tokens_within_cfg_attr(meta: Meta) -> Option<FxHashSet<SyntaxElement>> { + let mut remove: FxHashSet<SyntaxElement> = FxHashSet::default(); + debug!("Enabling attribute {}", meta); + let meta_path = meta.path()?; + debug!("Removing {:?}", meta_path.syntax()); + remove.insert(meta_path.syntax().clone().into()); + + let meta_tt = meta.token_tree()?; + debug!("meta_tt {}", meta_tt); + let mut stage = CfgExprStage::StrippigCfgExpr; + for tt in meta_tt.token_trees_and_tokens() { + debug!("Checking {:?}. Stage: {:?}", tt, stage); + match (stage, tt) { + (CfgExprStage::StrippigCfgExpr, syntax::NodeOrToken::Node(node)) => { + remove.insert(node.syntax().clone().into()); + } + (CfgExprStage::StrippigCfgExpr, syntax::NodeOrToken::Token(token)) => { + if token.kind() == T![,] { + stage = CfgExprStage::FoundComma; + } + remove.insert(token.into()); + } + (CfgExprStage::FoundComma, syntax::NodeOrToken::Token(token)) + if (token.kind() == T![,] || token.kind() == T![')']) => + { + // The end of the attribute or separator for the next attribute + stage = CfgExprStage::EverythingElse; + remove.insert(token.into()); + } + (CfgExprStage::EverythingElse, syntax::NodeOrToken::Node(node)) => { + remove.insert(node.syntax().clone().into()); + } + (CfgExprStage::EverythingElse, syntax::NodeOrToken::Token(token)) => { + remove.insert(token.into()); + } + // This is an actual attribute + _ => {} + } + } + if stage != CfgExprStage::EverythingElse { + warn!("Invalid cfg_attr attribute. {:?}", meta_tt); + return None; + } + Some(remove) +} +/// Removes a possible comma after the [AstNode] +fn remove_possible_comma(item: &impl AstNode, res: &mut FxHashSet<SyntaxElement>) { + if let Some(comma) = item.syntax().next_sibling_or_token().filter(|it| it.kind() == T![,]) { + res.insert(comma); + } +} +fn process_enum( + variants: VariantList, + loc: &MacroCallLoc, + db: &dyn ExpandDatabase, + remove: &mut FxHashSet<SyntaxElement>, +) -> Option<()> { + 'variant: for variant in variants.variants() { + for attr in variant.attrs() { + if check_cfg_attr(&attr, loc, db).map(|enabled| !enabled).unwrap_or_default() { + // Rustc does not strip the attribute if it is enabled. So we will will leave it + debug!("censoring type {:?}", variant.syntax()); + remove.insert(variant.syntax().clone().into()); + // We need to remove the , as well + remove_possible_comma(&variant, remove); + continue 'variant; + }; + + if let Some(enabled) = check_cfg_attr_attr(&attr, loc, db) { + if enabled { + debug!("Removing cfg_attr tokens {:?}", attr); + let meta = attr.meta()?; + let removes_from_cfg_attr = remove_tokens_within_cfg_attr(meta)?; + remove.extend(removes_from_cfg_attr); + } else { + debug!("censoring type cfg_attr {:?}", variant.syntax()); + remove.insert(attr.syntax().clone().into()); + continue; + } + } + } + if let Some(fields) = variant.field_list() { + match fields { + ast::FieldList::RecordFieldList(fields) => { + process_has_attrs_with_possible_comma(fields.fields(), loc, db, remove)?; + } + ast::FieldList::TupleFieldList(fields) => { + process_has_attrs_with_possible_comma(fields.fields(), loc, db, remove)?; + } + } + } + } + Some(()) +} + +pub(crate) fn process_cfg_attrs( + node: &SyntaxNode, + loc: &MacroCallLoc, + db: &dyn ExpandDatabase, +) -> Option<FxHashSet<SyntaxElement>> { + // FIXME: #[cfg_eval] is not implemented. But it is not stable yet + if !matches!(loc.kind, MacroCallKind::Derive { .. }) { + return None; + } + let mut remove = FxHashSet::default(); + + let item = ast::Item::cast(node.clone())?; + for attr in item.attrs() { + if let Some(enabled) = check_cfg_attr_attr(&attr, loc, db) { + if enabled { + debug!("Removing cfg_attr tokens {:?}", attr); + let meta = attr.meta()?; + let removes_from_cfg_attr = remove_tokens_within_cfg_attr(meta)?; + remove.extend(removes_from_cfg_attr); + } else { + debug!("censoring type cfg_attr {:?}", item.syntax()); + remove.insert(attr.syntax().clone().into()); + continue; + } + } + } + match item { + ast::Item::Struct(it) => match it.field_list()? { + ast::FieldList::RecordFieldList(fields) => { + process_has_attrs_with_possible_comma(fields.fields(), loc, db, &mut remove)?; + } + ast::FieldList::TupleFieldList(fields) => { + process_has_attrs_with_possible_comma(fields.fields(), loc, db, &mut remove)?; + } + }, + ast::Item::Enum(it) => { + process_enum(it.variant_list()?, loc, db, &mut remove)?; + } + ast::Item::Union(it) => { + process_has_attrs_with_possible_comma( + it.record_field_list()?.fields(), + loc, + db, + &mut remove, + )?; + } + // FIXME: Implement for other items if necessary. As we do not support #[cfg_eval] yet, we do not need to implement it for now + _ => {} + } + Some(remove) +} +/// Parses a `cfg` attribute from the meta +fn parse_from_attr_meta(meta: Meta) -> Option<CfgExpr> { + let tt = meta.token_tree()?; + let mut iter = tt.token_trees_and_tokens().skip(1).peekable(); + next_cfg_expr_from_syntax(&mut iter) +} + +fn next_cfg_expr_from_syntax<I>(iter: &mut Peekable<I>) -> Option<CfgExpr> +where + I: Iterator<Item = NodeOrToken<ast::TokenTree, syntax::SyntaxToken>>, +{ + let name = match iter.next() { + None => return None, + Some(NodeOrToken::Token(element)) => match element.kind() { + syntax::T![ident] => SmolStr::new(element.text()), + _ => return Some(CfgExpr::Invalid), + }, + Some(_) => return Some(CfgExpr::Invalid), + }; + let result = match name.as_str() { + "all" | "any" | "not" => { + let mut preds = Vec::new(); + let Some(NodeOrToken::Node(tree)) = iter.next() else { + return Some(CfgExpr::Invalid); + }; + let mut tree_iter = tree.token_trees_and_tokens().skip(1).peekable(); + while tree_iter + .peek() + .filter( + |element| matches!(element, NodeOrToken::Token(token) if (token.kind() != syntax::T![')'])), + ) + .is_some() + { + let pred = next_cfg_expr_from_syntax(&mut tree_iter); + if let Some(pred) = pred { + preds.push(pred); + } + } + let group = match name.as_str() { + "all" => CfgExpr::All(preds), + "any" => CfgExpr::Any(preds), + "not" => CfgExpr::Not(Box::new(preds.pop().unwrap_or(CfgExpr::Invalid))), + _ => unreachable!(), + }; + Some(group) + } + _ => match iter.peek() { + Some(NodeOrToken::Token(element)) if (element.kind() == syntax::T![=]) => { + iter.next(); + match iter.next() { + Some(NodeOrToken::Token(value_token)) + if (value_token.kind() == syntax::SyntaxKind::STRING) => + { + let value = value_token.text(); + let value = SmolStr::new(value.trim_matches('"')); + Some(CfgExpr::Atom(CfgAtom::KeyValue { key: name, value })) + } + _ => None, + } + } + _ => Some(CfgExpr::Atom(CfgAtom::Flag(name))), + }, + }; + if let Some(NodeOrToken::Token(element)) = iter.peek() { + if element.kind() == syntax::T![,] { + iter.next(); + } + } + result +} +#[cfg(test)] +mod tests { + use cfg::DnfExpr; + use expect_test::{expect, Expect}; + use syntax::{ast::Attr, AstNode, SourceFile}; + + use crate::cfg_process::parse_from_attr_meta; + + fn check_dnf_from_syntax(input: &str, expect: Expect) { + let parse = SourceFile::parse(input); + let node = match parse.tree().syntax().descendants().find_map(Attr::cast) { + Some(it) => it, + None => { + let node = std::any::type_name::<Attr>(); + panic!("Failed to make ast node `{node}` from text {input}") + } + }; + let node = node.clone_subtree(); + assert_eq!(node.syntax().text_range().start(), 0.into()); + + let cfg = parse_from_attr_meta(node.meta().unwrap()).unwrap(); + let actual = format!("#![cfg({})]", DnfExpr::new(cfg)); + expect.assert_eq(&actual); + } + #[test] + fn cfg_from_attr() { + check_dnf_from_syntax(r#"#[cfg(test)]"#, expect![[r#"#![cfg(test)]"#]]); + check_dnf_from_syntax(r#"#[cfg(not(never))]"#, expect![[r#"#![cfg(not(never))]"#]]); + } +} |