2 files changed, 109 insertions, 19 deletions

diff --git a/crates/ra_hir_expand/src/db.rs b/crates/ra_hir_expand/src/db.rs
index a4ee9a529..8abfbb4ff 100644
--- a/crates/ra_hir_expand/src/db.rs
+++ b/crates/ra_hir_expand/src/db.rs
@@ -8,10 +8,16 @@ use ra_prof::profile;
 use ra_syntax::{AstNode, Parse, SyntaxNode};
 
 use crate::{
-    ast_id_map::AstIdMap, HirFileId, HirFileIdRepr, MacroCallId, MacroCallLoc, MacroDefId,
-    MacroFile, MacroFileKind,
+    ast_id_map::AstIdMap, ExpansionInfo, HirFileId, HirFileIdRepr, MacroCallId, MacroCallLoc,
+    MacroDefId, MacroFile, MacroFileKind,
 };
 
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub struct ParseMacroWithInfo {
+    pub parsed: Parse<SyntaxNode>,
+    pub expansion_info: Arc<ExpansionInfo>,
+}
+
 // FIXME: rename to ExpandDatabase
 #[salsa::query_group(AstDatabaseStorage)]
 pub trait AstDatabase: SourceDatabase {
@@ -22,10 +28,16 @@ pub trait AstDatabase: SourceDatabase {
 
     #[salsa::interned]
     fn intern_macro(&self, macro_call: MacroCallLoc) -> MacroCallId;
-    fn macro_arg(&self, id: MacroCallId) -> Option<Arc<tt::Subtree>>;
-    fn macro_def(&self, id: MacroDefId) -> Option<Arc<mbe::MacroRules>>;
+    fn macro_arg(&self, id: MacroCallId) -> Option<(Arc<tt::Subtree>, Arc<mbe::TokenMap>)>;
+    fn macro_def(&self, id: MacroDefId) -> Option<(Arc<mbe::MacroRules>, Arc<mbe::TokenMap>)>;
     fn parse_macro(&self, macro_file: MacroFile) -> Option<Parse<SyntaxNode>>;
-    fn macro_expand(&self, macro_call: MacroCallId) -> Result<Arc<tt::Subtree>, String>;
+    fn parse_macro_with_info(&self, macro_file: MacroFile) -> Option<ParseMacroWithInfo>;
+    fn macro_expand(
+        &self,
+        macro_call: MacroCallId,
+    ) -> Result<(Arc<tt::Subtree>, (Arc<mbe::TokenMap>, Arc<mbe::TokenMap>)), String>;
+
+    fn macro_expansion_info(&self, macro_file: MacroFile) -> Option<Arc<ExpansionInfo>>;
 }
 
 pub(crate) fn ast_id_map(db: &dyn AstDatabase, file_id: HirFileId) -> Arc<AstIdMap> {
@@ -34,10 +46,13 @@ pub(crate) fn ast_id_map(db: &dyn AstDatabase, file_id: HirFileId) -> Arc<AstIdM
     Arc::new(map)
 }
 
-pub(crate) fn macro_def(db: &dyn AstDatabase, id: MacroDefId) -> Option<Arc<MacroRules>> {
+pub(crate) fn macro_def(
+    db: &dyn AstDatabase,
+    id: MacroDefId,
+) -> Option<(Arc<mbe::MacroRules>, Arc<mbe::TokenMap>)> {
     let macro_call = id.ast_id.to_node(db);
     let arg = macro_call.token_tree()?;
-    let (tt, _) = mbe::ast_to_token_tree(&arg).or_else(|| {
+    let (tt, tmap) = mbe::ast_to_token_tree(&arg).or_else(|| {
         log::warn!("fail on macro_def to token tree: {:#?}", arg);
         None
     })?;
@@ -45,32 +60,36 @@ pub(crate) fn macro_def(db: &dyn AstDatabase, id: MacroDefId) -> Option<Arc<Macr
         log::warn!("fail on macro_def parse: {:#?}", tt);
         None
     })?;
-    Some(Arc::new(rules))
+    Some((Arc::new(rules), Arc::new(tmap)))
 }
 
-pub(crate) fn macro_arg(db: &dyn AstDatabase, id: MacroCallId) -> Option<Arc<tt::Subtree>> {
+pub(crate) fn macro_arg(
+    db: &dyn AstDatabase,
+    id: MacroCallId,
+) -> Option<(Arc<tt::Subtree>, Arc<mbe::TokenMap>)> {
     let loc = db.lookup_intern_macro(id);
     let macro_call = loc.ast_id.to_node(db);
     let arg = macro_call.token_tree()?;
-    let (tt, _) = mbe::ast_to_token_tree(&arg)?;
-    Some(Arc::new(tt))
+    let (tt, tmap) = mbe::ast_to_token_tree(&arg)?;
+    Some((Arc::new(tt), Arc::new(tmap)))
 }
 
 pub(crate) fn macro_expand(
     db: &dyn AstDatabase,
     id: MacroCallId,
-) -> Result<Arc<tt::Subtree>, String> {
+) -> Result<(Arc<tt::Subtree>, (Arc<mbe::TokenMap>, Arc<mbe::TokenMap>)), String> {
     let loc = db.lookup_intern_macro(id);
     let macro_arg = db.macro_arg(id).ok_or("Fail to args in to tt::TokenTree")?;
 
     let macro_rules = db.macro_def(loc.def).ok_or("Fail to find macro definition")?;
-    let tt = macro_rules.expand(&macro_arg).map_err(|err| format!("{:?}", err))?;
+    let tt = macro_rules.0.expand(&macro_arg.0).map_err(|err| format!("{:?}", err))?;
     // Set a hard limit for the expanded tt
     let count = tt.count();
     if count > 65536 {
         return Err(format!("Total tokens count exceed limit : count = {}", count));
     }
-    Ok(Arc::new(tt))
+
+    Ok((Arc::new(tt), (macro_arg.1.clone(), macro_rules.1.clone())))
 }
 
 pub(crate) fn parse_or_expand(db: &dyn AstDatabase, file_id: HirFileId) -> Option<SyntaxNode> {
@@ -87,6 +106,13 @@ pub(crate) fn parse_macro(
     macro_file: MacroFile,
 ) -> Option<Parse<SyntaxNode>> {
     let _p = profile("parse_macro_query");
+    db.parse_macro_with_info(macro_file).map(|r| r.parsed)
+}
+
+pub(crate) fn parse_macro_with_info(
+    db: &dyn AstDatabase,
+    macro_file: MacroFile,
+) -> Option<ParseMacroWithInfo> {
     let macro_call_id = macro_file.macro_call_id;
     let tt = db
         .macro_expand(macro_call_id)
@@ -97,8 +123,39 @@ pub(crate) fn parse_macro(
             log::warn!("fail on macro_parse: (reason: {})", err,);
         })
         .ok()?;
-    match macro_file.macro_file_kind {
-        MacroFileKind::Items => mbe::token_tree_to_items(&tt).ok().map(Parse::to_syntax),
-        MacroFileKind::Expr => mbe::token_tree_to_expr(&tt).ok().map(Parse::to_syntax),
-    }
+    let res = match macro_file.macro_file_kind {
+        MacroFileKind::Items => {
+            mbe::token_tree_to_items(&tt.0).ok().map(|(p, map)| (Parse::to_syntax(p), map))
+        }
+        MacroFileKind::Expr => {
+            mbe::token_tree_to_expr(&tt.0).ok().map(|(p, map)| (Parse::to_syntax(p), map))
+        }
+    };
+
+    res.map(|(parsed, exp_map)| {
+        let (arg_map, def_map) = tt.1;
+        let loc: MacroCallLoc = db.lookup_intern_macro(macro_call_id);
+
+        let def_start =
+            loc.def.ast_id.to_node(db).token_tree().map(|t| t.syntax().text_range().start());
+        let arg_start =
+            loc.ast_id.to_node(db).token_tree().map(|t| t.syntax().text_range().start());
+
+        let arg_map =
+            arg_start.map(|start| exp_map.ranges(&arg_map, start)).unwrap_or_else(|| Vec::new());
+
+        let def_map =
+            def_start.map(|start| exp_map.ranges(&def_map, start)).unwrap_or_else(|| Vec::new());
+
+        let info = ExpansionInfo { arg_map, def_map };
+
+        ParseMacroWithInfo { parsed, expansion_info: Arc::new(info) }
+    })
+}
+
+pub(crate) fn macro_expansion_info(
+    db: &dyn AstDatabase,
+    macro_file: MacroFile,
+) -> Option<Arc<ExpansionInfo>> {
+    db.parse_macro_with_info(macro_file).map(|res| res.expansion_info.clone())
 }
diff --git a/crates/ra_hir_expand/src/lib.rs b/crates/ra_hir_expand/src/lib.rs
index dd07a16b4..194020b45 100644
--- a/crates/ra_hir_expand/src/lib.rs
+++ b/crates/ra_hir_expand/src/lib.rs
@@ -16,7 +16,7 @@ use std::hash::{Hash, Hasher};
 use ra_db::{salsa, CrateId, FileId};
 use ra_syntax::{
     ast::{self, AstNode},
-    SyntaxNode,
+    SyntaxNode, TextRange,
 };
 
 use crate::ast_id_map::FileAstId;
@@ -112,6 +112,39 @@ impl MacroCallId {
     }
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+/// ExpansionInfo mainly describle how to map text range between src and expaned macro
+pub struct ExpansionInfo {
+    pub arg_map: Vec<(TextRange, TextRange)>,
+    pub def_map: Vec<(TextRange, TextRange)>,
+}
+
+impl ExpansionInfo {
+    pub fn find_range(
+        &self,
+        from: TextRange,
+        (arg_file_id, def_file_id): (HirFileId, HirFileId),
+    ) -> Option<(HirFileId, TextRange)> {
+        for (src, dest) in &self.arg_map {
+            dbg!((src, *dest, "arg_map"));
+            if src.is_subrange(&from) {
+                dbg!((arg_file_id, *dest));
+                return Some((arg_file_id, *dest));
+            }
+        }
+
+        for (src, dest) in &self.def_map {
+            dbg!((src, *dest, "def_map"));
+            if src.is_subrange(&from) {
+                dbg!((arg_file_id, *dest));
+                return Some((def_file_id, *dest));
+            }
+        }
+
+        None
+    }
+}
+
 /// `AstId` points to an AST node in any file.
 ///
 /// It is stable across reparses, and can be used as salsa key/value.