Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/ide-ssr/src/lib.rs')
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diff --git a/crates/ide-ssr/src/lib.rs b/crates/ide-ssr/src/lib.rs new file mode 100644 index 0000000000..7b4e53ed24 --- /dev/null +++ b/crates/ide-ssr/src/lib.rs @@ -0,0 +1,356 @@ +//! Structural Search Replace +//! +//! Allows searching the AST for code that matches one or more patterns and then replacing that code +//! based on a template. + +// Feature: Structural Search and Replace +// +// Search and replace with named wildcards that will match any expression, type, path, pattern or item. +// The syntax for a structural search replace command is `<search_pattern> ==>> <replace_pattern>`. +// A `$<name>` placeholder in the search pattern will match any AST node and `$<name>` will reference it in the replacement. +// Within a macro call, a placeholder will match up until whatever token follows the placeholder. +// +// All paths in both the search pattern and the replacement template must resolve in the context +// in which this command is invoked. Paths in the search pattern will then match the code if they +// resolve to the same item, even if they're written differently. For example if we invoke the +// command in the module `foo` with a pattern of `Bar`, then code in the parent module that refers +// to `foo::Bar` will match. +// +// Paths in the replacement template will be rendered appropriately for the context in which the +// replacement occurs. For example if our replacement template is `foo::Bar` and we match some +// code in the `foo` module, we'll insert just `Bar`. +// +// Inherent method calls should generally be written in UFCS form. e.g. `foo::Bar::baz($s, $a)` will +// match `$s.baz($a)`, provided the method call `baz` resolves to the method `foo::Bar::baz`. When a +// placeholder is the receiver of a method call in the search pattern (e.g. `$s.foo()`), but not in +// the replacement template (e.g. `bar($s)`), then *, & and &mut will be added as needed to mirror +// whatever autoderef and autoref was happening implicitly in the matched code. +// +// The scope of the search / replace will be restricted to the current selection if any, otherwise +// it will apply to the whole workspace. +// +// Placeholders may be given constraints by writing them as `${<name>:<constraint1>:<constraint2>...}`. +// +// Supported constraints: +// +// |=== +// | Constraint | Restricts placeholder +// +// | kind(literal) | Is a literal (e.g. `42` or `"forty two"`) +// | not(a) | Negates the constraint `a` +// |=== +// +// Available via the command `rust-analyzer.ssr`. +// +// ```rust +// // Using structural search replace command [foo($a, $b) ==>> ($a).foo($b)] +// +// // BEFORE +// String::from(foo(y + 5, z)) +// +// // AFTER +// String::from((y + 5).foo(z)) +// ``` +// +// |=== +// | Editor | Action Name +// +// | VS Code | **Rust Analyzer: Structural Search Replace** +// |=== +// +// Also available as an assist, by writing a comment containing the structural +// search and replace rule. You will only see the assist if the comment can +// be parsed as a valid structural search and replace rule. +// +// ```rust +// // Place the cursor on the line below to see the assist 💡. +// // foo($a, $b) ==>> ($a).foo($b) +// ``` + +mod from_comment; +mod matching; +mod nester; +mod parsing; +mod fragments; +mod replacing; +mod resolving; +mod search; +#[macro_use] +mod errors; +#[cfg(test)] +mod tests; + +pub use crate::{errors::SsrError, from_comment::ssr_from_comment, matching::Match}; + +use crate::{errors::bail, matching::MatchFailureReason}; +use hir::Semantics; +use ide_db::{ + base_db::{FileId, FilePosition, FileRange}, + FxHashMap, +}; +use resolving::ResolvedRule; +use syntax::{ast, AstNode, SyntaxNode, TextRange}; +use text_edit::TextEdit; + +// A structured search replace rule. Create by calling `parse` on a str. +#[derive(Debug)] +pub struct SsrRule { + /// A structured pattern that we're searching for. + pattern: parsing::RawPattern, + /// What we'll replace it with. + template: parsing::RawPattern, + parsed_rules: Vec<parsing::ParsedRule>, +} + +#[derive(Debug)] +pub struct SsrPattern { + parsed_rules: Vec<parsing::ParsedRule>, +} + +#[derive(Debug, Default)] +pub struct SsrMatches { + pub matches: Vec<Match>, +} + +/// Searches a crate for pattern matches and possibly replaces them with something else. +pub struct MatchFinder<'db> { + /// Our source of information about the user's code. + sema: Semantics<'db, ide_db::RootDatabase>, + rules: Vec<ResolvedRule>, + resolution_scope: resolving::ResolutionScope<'db>, + restrict_ranges: Vec<FileRange>, +} + +impl<'db> MatchFinder<'db> { + /// Constructs a new instance where names will be looked up as if they appeared at + /// `lookup_context`. + pub fn in_context( + db: &'db ide_db::RootDatabase, + lookup_context: FilePosition, + mut restrict_ranges: Vec<FileRange>, + ) -> Result<MatchFinder<'db>, SsrError> { + restrict_ranges.retain(|range| !range.range.is_empty()); + let sema = Semantics::new(db); + let resolution_scope = resolving::ResolutionScope::new(&sema, lookup_context) + .ok_or_else(|| SsrError("no resolution scope for file".into()))?; + Ok(MatchFinder { sema, rules: Vec::new(), resolution_scope, restrict_ranges }) + } + + /// Constructs an instance using the start of the first file in `db` as the lookup context. + pub fn at_first_file(db: &'db ide_db::RootDatabase) -> Result<MatchFinder<'db>, SsrError> { + use ide_db::base_db::SourceDatabaseExt; + use ide_db::symbol_index::SymbolsDatabase; + if let Some(first_file_id) = + db.local_roots().iter().next().and_then(|root| db.source_root(*root).iter().next()) + { + MatchFinder::in_context( + db, + FilePosition { file_id: first_file_id, offset: 0.into() }, + vec![], + ) + } else { + bail!("No files to search"); + } + } + + /// Adds a rule to be applied. The order in which rules are added matters. Earlier rules take + /// precedence. If a node is matched by an earlier rule, then later rules won't be permitted to + /// match to it. + pub fn add_rule(&mut self, rule: SsrRule) -> Result<(), SsrError> { + for parsed_rule in rule.parsed_rules { + self.rules.push(ResolvedRule::new( + parsed_rule, + &self.resolution_scope, + self.rules.len(), + )?); + } + Ok(()) + } + + /// Finds matches for all added rules and returns edits for all found matches. + pub fn edits(&self) -> FxHashMap<FileId, TextEdit> { + use ide_db::base_db::SourceDatabaseExt; + let mut matches_by_file = FxHashMap::default(); + for m in self.matches().matches { + matches_by_file + .entry(m.range.file_id) + .or_insert_with(SsrMatches::default) + .matches + .push(m); + } + matches_by_file + .into_iter() + .map(|(file_id, matches)| { + ( + file_id, + replacing::matches_to_edit( + &matches, + &self.sema.db.file_text(file_id), + &self.rules, + ), + ) + }) + .collect() + } + + /// Adds a search pattern. For use if you intend to only call `find_matches_in_file`. If you + /// intend to do replacement, use `add_rule` instead. + pub fn add_search_pattern(&mut self, pattern: SsrPattern) -> Result<(), SsrError> { + for parsed_rule in pattern.parsed_rules { + self.rules.push(ResolvedRule::new( + parsed_rule, + &self.resolution_scope, + self.rules.len(), + )?); + } + Ok(()) + } + + /// Returns matches for all added rules. + pub fn matches(&self) -> SsrMatches { + let mut matches = Vec::new(); + let mut usage_cache = search::UsageCache::default(); + for rule in &self.rules { + self.find_matches_for_rule(rule, &mut usage_cache, &mut matches); + } + nester::nest_and_remove_collisions(matches, &self.sema) + } + + /// Finds all nodes in `file_id` whose text is exactly equal to `snippet` and attempts to match + /// them, while recording reasons why they don't match. This API is useful for command + /// line-based debugging where providing a range is difficult. + pub fn debug_where_text_equal(&self, file_id: FileId, snippet: &str) -> Vec<MatchDebugInfo> { + use ide_db::base_db::SourceDatabaseExt; + let file = self.sema.parse(file_id); + let mut res = Vec::new(); + let file_text = self.sema.db.file_text(file_id); + let mut remaining_text = file_text.as_str(); + let mut base = 0; + let len = snippet.len() as u32; + while let Some(offset) = remaining_text.find(snippet) { + let start = base + offset as u32; + let end = start + len; + self.output_debug_for_nodes_at_range( + file.syntax(), + FileRange { file_id, range: TextRange::new(start.into(), end.into()) }, + &None, + &mut res, + ); + remaining_text = &remaining_text[offset + snippet.len()..]; + base = end; + } + res + } + + fn output_debug_for_nodes_at_range( + &self, + node: &SyntaxNode, + range: FileRange, + restrict_range: &Option<FileRange>, + out: &mut Vec<MatchDebugInfo>, + ) { + for node in node.children() { + let node_range = self.sema.original_range(&node); + if node_range.file_id != range.file_id || !node_range.range.contains_range(range.range) + { + continue; + } + if node_range.range == range.range { + for rule in &self.rules { + // For now we ignore rules that have a different kind than our node, otherwise + // we get lots of noise. If at some point we add support for restricting rules + // to a particular kind of thing (e.g. only match type references), then we can + // relax this. We special-case expressions, since function calls can match + // method calls. + if rule.pattern.node.kind() != node.kind() + && !(ast::Expr::can_cast(rule.pattern.node.kind()) + && ast::Expr::can_cast(node.kind())) + { + continue; + } + out.push(MatchDebugInfo { + matched: matching::get_match(true, rule, &node, restrict_range, &self.sema) + .map_err(|e| MatchFailureReason { + reason: e.reason.unwrap_or_else(|| { + "Match failed, but no reason was given".to_owned() + }), + }), + pattern: rule.pattern.node.clone(), + node: node.clone(), + }); + } + } else if let Some(macro_call) = ast::MacroCall::cast(node.clone()) { + if let Some(expanded) = self.sema.expand(¯o_call) { + if let Some(tt) = macro_call.token_tree() { + self.output_debug_for_nodes_at_range( + &expanded, + range, + &Some(self.sema.original_range(tt.syntax())), + out, + ); + } + } + } + self.output_debug_for_nodes_at_range(&node, range, restrict_range, out); + } + } +} + +pub struct MatchDebugInfo { + node: SyntaxNode, + /// Our search pattern parsed as an expression or item, etc + pattern: SyntaxNode, + matched: Result<Match, MatchFailureReason>, +} + +impl std::fmt::Debug for MatchDebugInfo { + fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { + match &self.matched { + Ok(_) => writeln!(f, "Node matched")?, + Err(reason) => writeln!(f, "Node failed to match because: {}", reason.reason)?, + } + writeln!( + f, + "============ AST ===========\n\ + {:#?}", + self.node + )?; + writeln!(f, "========= PATTERN ==========")?; + writeln!(f, "{:#?}", self.pattern)?; + writeln!(f, "============================")?; + Ok(()) + } +} + +impl SsrMatches { + /// Returns `self` with any nested matches removed and made into top-level matches. + pub fn flattened(self) -> SsrMatches { + let mut out = SsrMatches::default(); + self.flatten_into(&mut out); + out + } + + fn flatten_into(self, out: &mut SsrMatches) { + for mut m in self.matches { + for p in m.placeholder_values.values_mut() { + std::mem::take(&mut p.inner_matches).flatten_into(out); + } + out.matches.push(m); + } + } +} + +impl Match { + pub fn matched_text(&self) -> String { + self.matched_node.text().to_string() + } +} + +impl std::error::Error for SsrError {} + +#[cfg(test)] +impl MatchDebugInfo { + pub(crate) fn match_failure_reason(&self) -> Option<&str> { + self.matched.as_ref().err().map(|r| r.reason.as_str()) + } +} |