From 604bdc6ffeea69dffed6d03f10b2fd4e05d04cda Mon Sep 17 00:00:00 2001
From: Edwin Cheng <edwin0cheng@gmail.com>
Date: Tue, 5 Nov 2019 02:09:16 +0800
Subject: [PATCH] Use macro_rules shift to map text ranges

---
 crates/ra_hir_expand/src/db.rs     | 13 +++++++---
 crates/ra_mbe/src/lib.rs           |  4 +++
 crates/ra_mbe/src/syntax_bridge.rs | 41 ++++++++----------------------
 crates/ra_tt/src/lib.rs            | 19 ++------------
 4 files changed, 26 insertions(+), 51 deletions(-)

diff --git a/crates/ra_hir_expand/src/db.rs b/crates/ra_hir_expand/src/db.rs
index 8369c2b40f9..72c728c938a 100644
--- a/crates/ra_hir_expand/src/db.rs
+++ b/crates/ra_hir_expand/src/db.rs
@@ -151,10 +151,15 @@ pub(crate) fn parse_macro_with_info(
     let arg_start = arg_tt.map(|t| t.syntax().text_range().start());
     let def_start = def_tt.map(|t| t.syntax().text_range().start());
 
-    let arg_map =
-        arg_start.map(|start| exp_map.ranges(&expand_info.arg_map, start)).unwrap_or_default();
-    let def_map =
-        def_start.map(|start| exp_map.ranges(&expand_info.def_map, start)).unwrap_or_default();
+    let macro_rules = db.macro_def(loc.def).ok_or("Fail to find macro definition").ok()?.0;
+    let shift = macro_rules.shift();
+
+    let arg_map = arg_start
+        .map(|start| exp_map.map_ranges(&expand_info.arg_map, start, shift))
+        .unwrap_or_default();
+    let def_map = def_start
+        .map(|start| exp_map.map_ranges(&expand_info.def_map, start, 0))
+        .unwrap_or_default();
 
     let info = ExpansionInfo { arg_map, def_map };
 
diff --git a/crates/ra_mbe/src/lib.rs b/crates/ra_mbe/src/lib.rs
index 2926b29fd08..a0f1a68813e 100644
--- a/crates/ra_mbe/src/lib.rs
+++ b/crates/ra_mbe/src/lib.rs
@@ -118,6 +118,10 @@ impl MacroRules {
         shift_subtree(&mut tt, self.shift);
         mbe_expander::expand(self, &tt)
     }
+
+    pub fn shift(&self) -> u32 {
+        self.shift
+    }
 }
 
 impl Rule {
diff --git a/crates/ra_mbe/src/syntax_bridge.rs b/crates/ra_mbe/src/syntax_bridge.rs
index 2f21ad6e0aa..0c499cd03c3 100644
--- a/crates/ra_mbe/src/syntax_bridge.rs
+++ b/crates/ra_mbe/src/syntax_bridge.rs
@@ -12,31 +12,12 @@ use tt::buffer::{Cursor, TokenBuffer};
 
 use crate::subtree_source::SubtreeTokenSource;
 use crate::ExpandError;
-use std::sync::atomic::{AtomicU32, Ordering};
 
 /// Maps `tt::TokenId` to the relative range of the original token.
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq, Eq, Default)]
 pub struct TokenMap {
     /// Maps `tt::TokenId` to the *relative* source range.
     tokens: Vec<TextRange>,
-    map_id: u32,
-}
-
-static TOKEN_MAP_COUNTER: AtomicU32 = AtomicU32::new(0);
-
-/// Generate an unique token map id for each instance
-fn make_uniq_token_map_id() -> u32 {
-    let res = TOKEN_MAP_COUNTER.fetch_add(1, Ordering::SeqCst);
-    if res == std::u32::MAX {
-        panic!("TOKEN_MAP_COUNTER is overflowed");
-    }
-    res
-}
-
-impl std::default::Default for TokenMap {
-    fn default() -> TokenMap {
-        TokenMap { tokens: Default::default(), map_id: make_uniq_token_map_id() }
-    }
 }
 
 /// Maps relative range of the expanded syntax node to `tt::TokenId`
@@ -140,17 +121,14 @@ pub fn token_tree_to_items(
 
 impl TokenMap {
     pub fn relative_range_of(&self, tt: tt::TokenId) -> Option<TextRange> {
-        if self.map_id != tt.map_id() {
-            return None;
-        }
-        let idx = tt.token_id() as usize;
+        let idx = tt.0 as usize;
         self.tokens.get(idx).copied()
     }
 
     fn alloc(&mut self, relative_range: TextRange) -> tt::TokenId {
         let id = self.tokens.len();
         self.tokens.push(relative_range);
-        tt::TokenId::new(id as u32, self.map_id)
+        tt::TokenId(id as u32)
     }
 }
 
@@ -159,14 +137,17 @@ impl ExpandedRangeMap {
         self.ranges.push((relative_range, token_id.clone()))
     }
 
-    pub fn ranges(&self, to: &TokenMap, start: TextUnit) -> Vec<(TextRange, TextRange)> {
+    pub fn map_ranges(
+        &self,
+        to: &TokenMap,
+        start: TextUnit,
+        shift: u32,
+    ) -> Vec<(TextRange, TextRange)> {
         self.ranges
             .iter()
+            .filter_map(|(r, tid)| if shift <= tid.0 { Some((r, tid.0 - shift)) } else { None })
             .filter_map(|(r, tid)| {
-                if to.map_id != tid.map_id() {
-                    return None;
-                }
-                if let Some(to_range) = to.relative_range_of(*tid) {
+                if let Some(to_range) = to.relative_range_of(tt::TokenId(tid)) {
                     Some((*r, TextRange::from_to(to_range.start() + start, to_range.end() + start)))
                 } else {
                     None
diff --git a/crates/ra_tt/src/lib.rs b/crates/ra_tt/src/lib.rs
index 1449618f3ee..20c251ff459 100644
--- a/crates/ra_tt/src/lib.rs
+++ b/crates/ra_tt/src/lib.rs
@@ -25,26 +25,11 @@ use smol_str::SmolStr;
 /// source token and making sure that identities are preserved during macro
 /// expansion.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub struct TokenId {
-    token_id: u32,
-    map_id: u32,
-}
+pub struct TokenId(pub u32);
 
 impl TokenId {
-    pub fn new(token_id: u32, map_id: u32) -> TokenId {
-        TokenId { token_id, map_id }
-    }
-
     pub const fn unspecified() -> TokenId {
-        TokenId { token_id: !0, map_id: !0 }
-    }
-
-    pub fn token_id(&self) -> u32 {
-        self.token_id
-    }
-
-    pub fn map_id(&self) -> u32 {
-        self.map_id
+        TokenId(!0)
     }
 }