Merge pull request #35536 from bfredl/skipahead

perf(highlight): allow decoration providers to skip ranges without data

fixes #35644

2 files changed, 33 insertions, 14 deletions

diff --git a/src/nvim/lua/executor.c b/src/nvim/lua/executor.c
index e3b7abde46..1cedc73e92 100644
--- a/src/nvim/lua/executor.c
+++ b/src/nvim/lua/executor.c
@@ -181,12 +181,9 @@ int nlua_pcall(lua_State *lstate, int nargs, int nresults)
     lua_remove(lstate, -2);
   } else {
     if (nresults == LUA_MULTRET) {
-      int new_top = lua_gettop(lstate);
-      int actual_nres = new_top - pre_top + nargs + 1;
-      lua_remove(lstate, -1 - actual_nres);
-    } else {
-      lua_remove(lstate, -1 - nresults);
+      nresults = lua_gettop(lstate) - (pre_top - nargs - 1);
     }
+    lua_remove(lstate, -1 - nresults);
   }
   return status;
 }
@@ -1551,6 +1548,7 @@ Object nlua_exec(const String str, const char *chunkname, const Array args, LuaR
 {
   lua_State *const lstate = global_lstate;
 
+  int top = lua_gettop(lstate);
   const char *name = (chunkname && chunkname[0]) ? chunkname : "<nvim>";
   if (luaL_loadbuffer(lstate, str.data, str.size, name)) {
     size_t len;
@@ -1570,7 +1568,7 @@ Object nlua_exec(const String str, const char *chunkname, const Array args, LuaR
     return NIL;
   }
 
-  return nlua_call_pop_retval(lstate, mode, arena, err);
+  return nlua_call_pop_retval(lstate, mode, arena, top, err);
 }
 
 bool nlua_ref_is_function(LuaRef ref)
@@ -1601,10 +1599,16 @@ Object nlua_call_ref(LuaRef ref, const char *name, Array args, LuaRetMode mode,
   return nlua_call_ref_ctx(false, ref, name, args, mode, arena, err);
 }
 
+static int mode_ret(LuaRetMode mode)
+{
+  return mode == kRetMulti ? LUA_MULTRET : 1;
+}
+
 Object nlua_call_ref_ctx(bool fast, LuaRef ref, const char *name, Array args, LuaRetMode mode,
                          Arena *arena, Error *err)
 {
   lua_State *const lstate = global_lstate;
+  int top = lua_gettop(lstate);
   nlua_pushref(lstate, ref);
   int nargs = (int)args.size;
   if (name != NULL) {
@@ -1616,12 +1620,12 @@ Object nlua_call_ref_ctx(bool fast, LuaRef ref, const char *name, Array args, Lu
   }
 
   if (fast) {
-    if (nlua_fast_cfpcall(lstate, nargs, 1, -1) < 0) {
+    if (nlua_fast_cfpcall(lstate, nargs, mode_ret(mode), -1) < 0) {
       // error is already scheduled, set anyways to convey failure.
       api_set_error(err, kErrorTypeException, "fast context failure");
       return NIL;
     }
-  } else if (nlua_pcall(lstate, nargs, 1)) {
+  } else if (nlua_pcall(lstate, nargs, mode_ret(mode))) {
     // if err is passed, the caller will deal with the error.
     if (err) {
       size_t len;
@@ -1633,16 +1637,18 @@ Object nlua_call_ref_ctx(bool fast, LuaRef ref, const char *name, Array args, Lu
     return NIL;
   }
 
-  return nlua_call_pop_retval(lstate, mode, arena, err);
+  return nlua_call_pop_retval(lstate, mode, arena, top, err);
 }
 
-static Object nlua_call_pop_retval(lua_State *lstate, LuaRetMode mode, Arena *arena, Error *err)
+static Object nlua_call_pop_retval(lua_State *lstate, LuaRetMode mode, Arena *arena, int pretop,
+                                   Error *err)
 {
-  if (lua_isnil(lstate, -1)) {
+  if (mode != kRetMulti && lua_isnil(lstate, -1)) {
     lua_pop(lstate, 1);
     return NIL;
   }
   Error dummy = ERROR_INIT;
+  Error *perr = err ? err : &dummy;
 
   switch (mode) {
   case kRetNilBool: {
@@ -1658,7 +1664,19 @@ static Object nlua_call_pop_retval(lua_State *lstate, LuaRetMode mode, Arena *ar
     return LUAREF_OBJ(ref);
   }
   case kRetObject:
-    return nlua_pop_Object(lstate, false, arena, err ? err : &dummy);
+    return nlua_pop_Object(lstate, false, arena, perr);
+  case kRetMulti:
+    ;
+    int nres = lua_gettop(lstate) - pretop;
+    Array res = arena_array(arena, (size_t)nres);
+    for (int i = 0; i < nres; i++) {
+      res.items[nres - i - 1] = nlua_pop_Object(lstate, false, arena, perr);
+      if (ERROR_SET(err)) {
+        return NIL;
+      }
+    }
+    res.size = (size_t)nres;
+    return ARRAY_OBJ(res);
   }
   UNREACHABLE;
 }
diff --git a/src/nvim/lua/executor.h b/src/nvim/lua/executor.h
index 9493015d10..c73b704a22 100644
--- a/src/nvim/lua/executor.h
+++ b/src/nvim/lua/executor.h
@@ -38,10 +38,11 @@ typedef struct {
   } while (0)
 
 typedef enum {
-  kRetObject,  ///< any object, but doesn't preserve nested luarefs
+  kRetObject,   ///< any object, but doesn't preserve nested luarefs
   kRetNilBool,  ///< NIL preserved as such, other values return their booleanness
                 ///< Should also be used when return value is ignored, as it is allocation-free
-  kRetLuaref,  ///< return value becomes a single Luaref, regardless of type (except NIL)
+  kRetLuaref,   ///< return value becomes a single Luaref, regardless of type (except NIL)
+  kRetMulti,    ///< like kRetObject but return muliple return values as an Array
 } LuaRetMode;
 
 /// Maximum number of errors in vim.ui_attach() and decor provider callbacks.