perf(ui): unpack grid_line (screen contents) directly

src/nvim/api/private/defs.h

@@ -36,6 +36,7 @@ typedef enum {
   kMessageTypeRequest = 0,
   kMessageTypeResponse = 1,
   kMessageTypeNotification = 2,
+  kMessageTypeRedrawEvent = 3,
 } MessageType;
 
 /// Mask for all internal calls

src/nvim/grid_defs.h

@@ -128,4 +128,13 @@ typedef struct {
   const char *start;       ///< Location where region starts.
 } StlClickRecord;
 
+typedef struct {
+  int args[3];
+  int icell;
+  int ncells;
+  int coloff;
+  int cur_attr;
+  int clear_width;
+} GridLineEvent;
+
 #endif  // NVIM_GRID_DEFS_H

src/nvim/msgpack_rpc/channel.c

@@ -239,11 +239,13 @@ static void parse_msgpack(Channel *channel)
 {
   Unpacker *p = channel->rpc.unpacker;
   while (unpacker_advance(p)) {
-    if (p->is_ui) {
+    if (p->type == kMessageTypeRedrawEvent) {
-      if (p->ui_handler.fn != NULL && p->result.type == kObjectTypeArray) {
+      if (p->grid_line_event) {
+        ui_client_event_raw_line(p->grid_line_event);
+      } else if (p->ui_handler.fn != NULL && p->result.type == kObjectTypeArray) {
         p->ui_handler.fn(p->result.data.array);
+        arena_mem_free(arena_finish(&p->arena), &p->reuse_blk);
       }
-      arena_mem_free(arena_finish(&p->arena), &p->reuse_blk);
     } else if (p->type == kMessageTypeResponse) {
       ChannelCallFrame *frame = kv_last(channel->rpc.call_stack);
       if (p->request_id != frame->request_id) {

src/nvim/msgpack_rpc/unpacker.c

@@ -6,6 +6,7 @@
 #include "nvim/memory.h"
 #include "nvim/msgpack_rpc/helpers.h"
 #include "nvim/msgpack_rpc/unpacker.h"
+#include "nvim/ui_client.h"
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "msgpack_rpc/unpacker.c.generated.h"
@@ -280,10 +281,20 @@ error:
 // is relatively small, just ~10 bytes + the method name. Thus we can simply refuse
 // to advance the stream beyond the header until it can be parsed in its entirety.
 //
-// Of course, later on, we want to specialize state 2 into sub-states depending
+// Later on, we want to specialize state 2 into more sub-states depending
 // on the specific method. "nvim_exec_lua" should just decode direct into lua
-// objects, and "redraw/grid_line" should use a hand-rolled decoder to avoid
+// objects. For the moment "redraw/grid_line" uses a hand-rolled decoder,
-// a blizzard of small objects for each screen cell.
+// to avoid a blizzard of small objects for each screen cell.
+//
+// <0>[2, "redraw", <10>[{11}["method", <12>[args], <12>[args], ...], <11>[...], ...]]
+//
+// Where [args] gets unpacked as an Array. Note: first {11} is not saved as a state.
+//
+// When method is "grid_line", we furthermore decode a cell at a time like:
+//
+// <0>[2, "redraw", <10>[{11}["grid_line", <13>[g, r, c, [<14>[cell], <14>[cell], ...]], ...], <11>[...], ...]]
+//
+// where [cell] is [char, repeat, attr], where 'repeat' and 'attr' is optional
 
 bool unpacker_advance(Unpacker *p)
 {
@@ -293,6 +304,7 @@ bool unpacker_advance(Unpacker *p)
       return false;
     }
     if (p->type == kMessageTypeNotification && p->handler.fn == handle_ui_client_redraw) {
+      p->type = kMessageTypeRedrawEvent;
       p->state = 10;
     } else {
       p->state = p->type == kMessageTypeResponse ? 1 : 2;
@@ -300,11 +312,18 @@ bool unpacker_advance(Unpacker *p)
     }
   }
 
-  if (p->state == 10 || p->state == 11) {
+  if (p->state >= 10 && p->state != 12) {
     if (!unpacker_parse_redraw(p)) {
       return false;
     }
-    arena_start(&p->arena, &p->reuse_blk);
+
+    if (p->state == 14) {
+      // grid_line event already unpacked
+      goto done;
+    } else {
+      // unpack other ui events using mpack_parse()
+      arena_start(&p->arena, &p->reuse_blk);
+    }
   }
 
   int result;
@@ -321,6 +340,7 @@ rerun:
     return false;
   }
 
+done:
   switch (p->state) {
   case 1:
     p->error = p->result;
@@ -328,28 +348,23 @@ rerun:
     goto rerun;
   case 2:
     p->state = 0;
-    p->is_ui = false;
     return true;
   case 12:
+  case 14:
     p->ncalls--;
     if (p->ncalls > 0) {
-      p->state = 12;
+      p->state = (p->state == 14) ? 13 : 12;
     } else if (p->nevents > 0) {
       p->state = 11;
     } else {
       p->state = 0;
     }
-    // TODO: fold into p->type
-    p->is_ui = true;
     return true;
   default:
     abort();
   }
 }
 
-// note: first {11} is not saved as a state
-// <0>[2, "redraw", <10>[{11}["method", <12>[args], <12>[args], ...], <11>[...], ...]]
-//
 bool unpacker_parse_redraw(Unpacker *p)
 {
   mpack_token_t tok;
@@ -357,40 +372,36 @@ bool unpacker_parse_redraw(Unpacker *p)
 
   const char *data = p->read_ptr;
   size_t size = p->read_size;
+  GridLineEvent *g = p->grid_line_event;
+
+#define NEXT_TYPE(tok, typ) \
+  result = mpack_rtoken(&data, &size, &tok); \
+  if (result == MPACK_EOF) { \
+    return false; \
+  } else if (result || (tok.type != typ \
+                        && !(typ == MPACK_TOKEN_STR && tok.type == MPACK_TOKEN_BIN) \
+                        && !(typ == MPACK_TOKEN_SINT && tok.type == MPACK_TOKEN_UINT))) { \
+    p->state = -1; \
+    return false; \
+  }
+
+redo:
   switch (p->state) {
   case 10:
-    result = mpack_rtoken(&data, &size, &tok);
+    NEXT_TYPE(tok, MPACK_TOKEN_ARRAY);
-    if (result == MPACK_EOF) {
-      return false;
-    } else if (result || tok.type != MPACK_TOKEN_ARRAY) {
-      p->state = -1;
-      return false;
-    }
-
     p->nevents = (int)tok.length;
     FALLTHROUGH;
 
   case 11:
-    result = mpack_rtoken(&data, &size, &tok);
+    NEXT_TYPE(tok, MPACK_TOKEN_ARRAY);
-    if (result == MPACK_EOF) {
-      return false;
-    } else if (result || tok.type != MPACK_TOKEN_ARRAY) {
-      abort();
-    }
-
     p->ncalls = (int)tok.length;
+
     if (p->ncalls-- == 0) {
       p->state = -1;
       return false;
     }
 
-    result = mpack_rtoken(&data, &size, &tok);
+    NEXT_TYPE(tok, MPACK_TOKEN_STR);
-    if (result == MPACK_EOF) {
-      return false;
-    } else if (result || (tok.type != MPACK_TOKEN_STR && tok.type != MPACK_TOKEN_BIN)) {
-      abort();
-    }
-
     if (tok.length > size) {
       return false;
     }
@@ -402,8 +413,98 @@ bool unpacker_parse_redraw(Unpacker *p)
     p->nevents--;
     p->read_ptr = data;
     p->read_size = size;
-    p->state = 12;
+    if (p->ui_handler.fn != ui_client_event_grid_line) {
-    return true;
+      p->state = 12;
+      if (p->grid_line_event) {
+        arena_mem_free(arena_finish(&p->arena), &p->reuse_blk);
+        p->grid_line_event = NULL;
+      }
+      return true;
+    } else {
+      p->state = 13;
+      arena_start(&p->arena, &p->reuse_blk);
+      p->grid_line_event = arena_alloc(&p->arena, sizeof *p->grid_line_event, true);
+      g = p->grid_line_event;
+      FALLTHROUGH;
+    }
+
+  case 13:
+    NEXT_TYPE(tok, MPACK_TOKEN_ARRAY);
+    int eventarrsize = (int)tok.length;
+    if (eventarrsize != 4) {
+      p->state = -1;
+      return false;
+    }
+
+    for (int i = 0; i < 3; i++) {
+      NEXT_TYPE(tok, MPACK_TOKEN_UINT);
+      g->args[i] = (int)tok.data.value.lo;
+    }
+
+    NEXT_TYPE(tok, MPACK_TOKEN_ARRAY);
+    g->ncells = (int)tok.length;
+    g->icell = 0;
+    g->coloff = 0;
+    g->cur_attr = -1;
+
+    p->read_ptr = data;
+    p->read_size = size;
+    p->state = 14;
+    FALLTHROUGH;
+
+  case 14:
+    assert(g->icell < g->ncells);
+
+    NEXT_TYPE(tok, MPACK_TOKEN_ARRAY);
+    int cellarrsize = (int)tok.length;
+    if (cellarrsize < 1 || cellarrsize > 3) {
+      p->state = -1;
+      return false;
+    }
+
+    NEXT_TYPE(tok, MPACK_TOKEN_STR);
+    if (tok.length > size) {
+      return false;
+    }
+
+    const char *cellbuf = data;
+    size_t cellsize = tok.length;
+    data += cellsize;
+    size -= cellsize;
+
+    if (cellarrsize >= 2) {
+      NEXT_TYPE(tok, MPACK_TOKEN_SINT);
+      g->cur_attr = (int)tok.data.value.lo;
+    }
+
+    int repeat = 1;
+    if (cellarrsize >= 3) {
+      NEXT_TYPE(tok, MPACK_TOKEN_UINT);
+      repeat = (int)tok.data.value.lo;
+    }
+
+    g->clear_width = 0;
+    if (g->icell == g->ncells - 1 && cellsize == 1 && cellbuf[0] == ' ' && repeat > 1) {
+      g->clear_width = repeat;
+    } else {
+      for (int r = 0; r < repeat; r++) {
+        if (g->coloff >= (int)grid_line_buf_size) {
+          p->state = -1;
+          return false;
+        }
+        memcpy(grid_line_buf_char[g->coloff], cellbuf, cellsize);
+        grid_line_buf_char[g->coloff][cellsize] = NUL;
+        grid_line_buf_attr[g->coloff++] = g->cur_attr;
+      }
+    }
+
+    g->icell++;
+    p->read_ptr = data;
+    p->read_size = size;
+    if (g->icell == g->ncells) {
+      return true;
+    }
+    goto redo;
 
   default:
     abort();

src/nvim/msgpack_rpc/unpacker.h

@@ -35,10 +35,10 @@ struct Unpacker {
   // one length free-list of reusable blocks
   ArenaMem reuse_blk;
 
-  bool is_ui;
   int nevents;
   int ncalls;
   UIClientHandler ui_handler;
+  GridLineEvent *grid_line_event;
 };
 
 // unrecovareble error. unpack_error should be set!

src/nvim/ui_client.c

@@ -22,11 +22,6 @@
 # include "ui_events_client.generated.h"
 #endif
 
-// Temporary buffer for converting a single grid_line event
-static size_t buf_size = 0;
-static schar_T *buf_char = NULL;
-static sattr_T *buf_attr = NULL;
-
 void ui_client_init(uint64_t chan)
 {
   Array args = ARRAY_DICT_INIT;
@@ -106,88 +101,30 @@ void ui_client_event_grid_resize(Array args)
   Integer height = args.items[2].data.integer;
   ui_call_grid_resize(grid, width, height);
 
-  if (buf_size < (size_t)width) {
+  if (grid_line_buf_size < (size_t)width) {
-    xfree(buf_char);
+    xfree(grid_line_buf_char);
-    xfree(buf_attr);
+    xfree(grid_line_buf_attr);
-    buf_size = (size_t)width;
+    grid_line_buf_size = (size_t)width;
-    buf_char = xmalloc(buf_size * sizeof(schar_T));
+    grid_line_buf_char = xmalloc(grid_line_buf_size * sizeof(schar_T));
-    buf_attr = xmalloc(buf_size * sizeof(sattr_T));
+    grid_line_buf_attr = xmalloc(grid_line_buf_size * sizeof(sattr_T));
   }
 }
 
 void ui_client_event_grid_line(Array args)
+  FUNC_ATTR_NORETURN
 {
-  if (args.size < 4
+  abort();  // unreachable
-      || args.items[0].type != kObjectTypeInteger
+}
-      || args.items[1].type != kObjectTypeInteger
-      || args.items[2].type != kObjectTypeInteger
-      || args.items[3].type != kObjectTypeArray) {
-    goto error;
-  }
 
-  Integer grid = args.items[0].data.integer;
+void ui_client_event_raw_line(GridLineEvent *g)
-  Integer row = args.items[1].data.integer;
+{
-  Integer startcol = args.items[2].data.integer;
+  int grid = g->args[0], row = g->args[1], startcol = g->args[2];
-  Array cells = args.items[3].data.array;
+  Integer endcol = startcol + g->coloff;
+  Integer clearcol = endcol + g->clear_width;
 
   // TODO(hlpr98): Accommodate other LineFlags when included in grid_line
   LineFlags lineflags = 0;
 
-  size_t j = 0;
+  ui_call_raw_line(grid, row, startcol, endcol, clearcol, g->cur_attr, lineflags,
-  int cur_attr = 0;
+                   (const schar_T *)grid_line_buf_char, grid_line_buf_attr);
-  int clear_attr = 0;
-  int clear_width = 0;
-  for (size_t i = 0; i < cells.size; i++) {
-    if (cells.items[i].type != kObjectTypeArray) {
-      goto error;
-    }
-    Array cell = cells.items[i].data.array;
-
-    if (cell.size < 1 || cell.items[0].type != kObjectTypeString) {
-      goto error;
-    }
-    String sstring = cell.items[0].data.string;
-
-    char *schar = sstring.data;
-    int repeat = 1;
-    if (cell.size >= 2) {
-      if (cell.items[1].type != kObjectTypeInteger
-          || cell.items[1].data.integer < 0) {
-        goto error;
-      }
-      cur_attr = (int)cell.items[1].data.integer;
-    }
-
-    if (cell.size >= 3) {
-      if (cell.items[2].type != kObjectTypeInteger
-          || cell.items[2].data.integer < 0) {
-        goto error;
-      }
-      repeat = (int)cell.items[2].data.integer;
-    }
-
-    if (i == cells.size - 1 && sstring.size == 1 && sstring.data[0] == ' ' && repeat > 1) {
-      clear_width = repeat;
-      break;
-    }
-
-    for (int r = 0; r < repeat; r++) {
-      if (j >= buf_size) {
-        goto error;  // _YIKES_
-      }
-      STRLCPY(buf_char[j], schar, sizeof(schar_T));
-      buf_attr[j++] = cur_attr;
-    }
-  }
-
-  Integer endcol = startcol + (int)j;
-  Integer clearcol = endcol + clear_width;
-  clear_attr = cur_attr;
-
-  ui_call_raw_line(grid, row, startcol, endcol, clearcol, clear_attr, lineflags,
-                   (const schar_T *)buf_char, (const sattr_T *)buf_attr);
-  return;
-
-error:
-  ELOG("Error handling ui event 'grid_line'");
 }

src/nvim/ui_client.h

@@ -2,12 +2,18 @@
 #define NVIM_UI_CLIENT_H
 
 #include "nvim/api/private/defs.h"
+#include "nvim/grid_defs.h"
 
 typedef struct {
   const char *name;
   void (*fn)(Array args);
 } UIClientHandler;
 
+// Temporary buffer for converting a single grid_line event
+EXTERN size_t grid_line_buf_size INIT(= 0);
+EXTERN schar_T *grid_line_buf_char INIT(= NULL);
+EXTERN sattr_T *grid_line_buf_attr INIT(= NULL);
+
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "ui_client.h.generated.h"