fix(paste): improve repeating of pasted text (#30438)

- Fixes 'autoindent' being applied during redo.
- Makes redoing a large paste significantly faster.
- Stores pasted text in the register being recorded.

Fix #28561

8 files changed, 233 insertions, 32 deletions

diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index d10ee91042..4b80369654 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -1259,30 +1259,19 @@ Boolean nvim_paste(String data, Boolean crlf, Integer phase, Arena *arena, Error
     draining = true;
     goto theend;
   }
-  if (!(State & (MODE_CMDLINE | MODE_INSERT)) && (phase == -1 || phase == 1)) {
-    ResetRedobuff();
-    AppendCharToRedobuff('a');  // Dot-repeat.
+  if (phase == -1 || phase == 1) {
+    paste_store(kFalse, NULL_STRING, crlf);
   }
   // vim.paste() decides if client should cancel.  Errors do NOT cancel: we
   // want to drain remaining chunks (rather than divert them to main input).
   cancel = (rv.type == kObjectTypeBoolean && !rv.data.boolean);
-  if (!cancel && !(State & MODE_CMDLINE)) {  // Dot-repeat.
-    for (size_t i = 0; i < lines.size; i++) {
-      String s = lines.items[i].data.string;
-      assert(s.size <= INT_MAX);
-      AppendToRedobuffLit(s.data, (int)s.size);
-      // readfile()-style: "\n" is indicated by presence of N+1 item.
-      if (i + 1 < lines.size) {
-        AppendCharToRedobuff(NL);
-      }
-    }
-  }
-  if (!(State & (MODE_CMDLINE | MODE_INSERT)) && (phase == -1 || phase == 3)) {
-    AppendCharToRedobuff(ESC);  // Dot-repeat.
+  if (!cancel) {
+    paste_store(kNone, data, crlf);
   }
 theend:
   if (cancel || phase == -1 || phase == 3) {  // End of paste-stream.
     draining = false;
+    paste_store(kTrue, NULL_STRING, crlf);
   }
 
   return !cancel;
diff --git a/src/nvim/edit.c b/src/nvim/edit.c
index 13623eaa91..f06dc124f0 100644
--- a/src/nvim/edit.c
+++ b/src/nvim/edit.c
@@ -907,6 +907,10 @@ static int insert_handle_key(InsertState *s)
   case K_IGNORE:      // Something mapped to nothing
     break;
 
+  case K_PASTE_START:
+    paste_repeat(1);
+    goto check_pum;
+
   case K_EVENT:       // some event
     state_handle_k_event();
     // If CTRL-G U was used apply it to the next typed key.
diff --git a/src/nvim/getchar.c b/src/nvim/getchar.c
index ba0b629896..31f31904e0 100644
--- a/src/nvim/getchar.c
+++ b/src/nvim/getchar.c
@@ -13,6 +13,7 @@
 
 #include "nvim/api/private/defs.h"
 #include "nvim/api/private/helpers.h"
+#include "nvim/api/vim.h"
 #include "nvim/ascii_defs.h"
 #include "nvim/buffer_defs.h"
 #include "nvim/charset.h"
@@ -308,6 +309,24 @@ static void add_num_buff(buffheader_T *buf, int n)
   add_buff(buf, number, -1);
 }
 
+/// Add byte or special key 'c' to buffer "buf".
+/// Translates special keys, NUL and K_SPECIAL.
+static void add_byte_buff(buffheader_T *buf, int c)
+{
+  char temp[4];
+  if (IS_SPECIAL(c) || c == K_SPECIAL || c == NUL) {
+    // Translate special key code into three byte sequence.
+    temp[0] = (char)K_SPECIAL;
+    temp[1] = (char)K_SECOND(c);
+    temp[2] = (char)K_THIRD(c);
+    temp[3] = NUL;
+  } else {
+    temp[0] = (char)c;
+    temp[1] = NUL;
+  }
+  add_buff(buf, temp, -1);
+}
+
 /// Add character 'c' to buffer "buf".
 /// Translates special keys, NUL, K_SPECIAL and multibyte characters.
 static void add_char_buff(buffheader_T *buf, int c)
@@ -325,19 +344,7 @@ static void add_char_buff(buffheader_T *buf, int c)
     if (!IS_SPECIAL(c)) {
       c = bytes[i];
     }
-
-    char temp[4];
-    if (IS_SPECIAL(c) || c == K_SPECIAL || c == NUL) {
-      // Translate special key code into three byte sequence.
-      temp[0] = (char)K_SPECIAL;
-      temp[1] = (char)K_SECOND(c);
-      temp[2] = (char)K_THIRD(c);
-      temp[3] = NUL;
-    } else {
-      temp[0] = (char)c;
-      temp[1] = NUL;
-    }
-    add_buff(buf, temp, -1);
+    add_byte_buff(buf, c);
   }
 }
 
@@ -3182,3 +3189,126 @@ bool map_execute_lua(bool may_repeat)
   ga_clear(&line_ga);
   return true;
 }
+
+static bool paste_repeat_active = false;  ///< true when paste_repeat() is pasting
+
+/// Wraps pasted text stream with K_PASTE_START and K_PASTE_END, and
+/// appends to redo buffer and/or record buffer if needed.
+/// Escapes all K_SPECIAL and NUL bytes in the content.
+///
+/// @param state  kFalse for the start of a paste
+///               kTrue for the end of a paste
+///               kNone for the content of a paste
+/// @param str    the content of the paste (only used when state is kNone)
+void paste_store(const TriState state, const String str, const bool crlf)
+{
+  if (State & MODE_CMDLINE) {
+    return;
+  }
+
+  const bool need_redo = !block_redo;
+  const bool need_record = reg_recording != 0 && !paste_repeat_active;
+
+  if (!need_redo && !need_record) {
+    return;
+  }
+
+  if (state != kNone) {
+    const int c = state == kFalse ? K_PASTE_START : K_PASTE_END;
+    if (need_redo) {
+      if (state == kFalse && !(State & MODE_INSERT)) {
+        ResetRedobuff();
+      }
+      add_char_buff(&redobuff, c);
+    }
+    if (need_record) {
+      add_char_buff(&recordbuff, c);
+    }
+    return;
+  }
+
+  const char *s = str.data;
+  const char *const str_end = str.data + str.size;
+
+  while (s < str_end) {
+    const char *start = s;
+    while (s < str_end && (uint8_t)(*s) != K_SPECIAL && *s != NUL
+           && *s != NL && !(crlf && *s == CAR)) {
+      s++;
+    }
+
+    if (s > start) {
+      if (need_redo) {
+        add_buff(&redobuff, start, s - start);
+      }
+      if (need_record) {
+        add_buff(&recordbuff, start, s - start);
+      }
+    }
+
+    if (s < str_end) {
+      int c = (uint8_t)(*s++);
+      if (crlf && c == CAR) {
+        if (s < str_end && *s == NL) {
+          s++;
+        }
+        c = NL;
+      }
+      if (need_redo) {
+        add_byte_buff(&redobuff, c);
+      }
+      if (need_record) {
+        add_byte_buff(&recordbuff, c);
+      }
+    }
+  }
+}
+
+/// Gets a paste stored by paste_store() from typeahead and repeats it.
+void paste_repeat(int count)
+{
+  garray_T ga = GA_INIT(1, 32);
+  bool aborted = false;
+
+  no_mapping++;
+
+  got_int = false;
+  while (!aborted) {
+    ga_grow(&ga, 32);
+    uint8_t c1 = (uint8_t)vgetorpeek(true);
+    if (c1 == K_SPECIAL) {
+      c1 = (uint8_t)vgetorpeek(true);
+      uint8_t c2 = (uint8_t)vgetorpeek(true);
+      int c = TO_SPECIAL(c1, c2);
+      if (c == K_PASTE_END) {
+        break;
+      } else if (c == K_ZERO) {
+        ga_append(&ga, NUL);
+      } else if (c == K_SPECIAL) {
+        ga_append(&ga, K_SPECIAL);
+      } else {
+        ga_append(&ga, K_SPECIAL);
+        ga_append(&ga, c1);
+        ga_append(&ga, c2);
+      }
+    } else {
+      ga_append(&ga, c1);
+    }
+    aborted = got_int;
+  }
+
+  no_mapping--;
+
+  String str = cbuf_as_string(ga.ga_data, (size_t)ga.ga_len);
+  Arena arena = ARENA_EMPTY;
+  Error err = ERROR_INIT;
+  paste_repeat_active = true;
+  for (int i = 0; !aborted && i < count; i++) {
+    nvim_paste(str, false, -1, &arena, &err);
+    aborted = ERROR_SET(&err);
+  }
+  paste_repeat_active = false;
+  api_clear_error(&err);
+  arena_mem_free(arena_finish(&arena));
+  ga_clear(&ga);
+}
diff --git a/src/nvim/keycodes.h b/src/nvim/keycodes.h
index 18af3f87d6..5a7ddd4847 100644
--- a/src/nvim/keycodes.h
+++ b/src/nvim/keycodes.h
@@ -380,6 +380,10 @@ enum key_extra {
 #define K_KENTER        TERMCAP2KEY('K', 'A')   // keypad Enter
 #define K_KPOINT        TERMCAP2KEY('K', 'B')   // keypad . or ,
 
+// Delimits pasted text (to repeat nvim_paste). Internal-only, not sent by UIs.
+#define K_PASTE_START   TERMCAP2KEY('P', 'S')   // paste start
+#define K_PASTE_END     TERMCAP2KEY('P', 'E')   // paste end
+
 #define K_K0            TERMCAP2KEY('K', 'C')   // keypad 0
 #define K_K1            TERMCAP2KEY('K', 'D')   // keypad 1
 #define K_K2            TERMCAP2KEY('K', 'E')   // keypad 2
diff --git a/src/nvim/normal.c b/src/nvim/normal.c
index b9ce891b49..be9987cc7f 100644
--- a/src/nvim/normal.c
+++ b/src/nvim/normal.c
@@ -351,6 +351,7 @@ static const struct nv_cmd {
   { K_F1,      nv_help,        NV_NCW,                 0 },
   { K_XF1,     nv_help,        NV_NCW,                 0 },
   { K_SELECT,  nv_select,      0,                      0 },
+  { K_PASTE_START, nv_paste,   NV_KEEPREG,             0 },
   { K_EVENT,   nv_event,       NV_KEEPREG,             0 },
   { K_COMMAND, nv_colon,       0,                      0 },
   { K_LUA, nv_colon,           0,                      0 },
@@ -6593,6 +6594,12 @@ static void nv_open(cmdarg_T *cap)
   }
 }
 
+/// Handles K_PASTE_START, repeats pasted text.
+static void nv_paste(cmdarg_T *cap)
+{
+  paste_repeat(cap->count1);
+}
+
 /// Handle an arbitrary event in normal mode
 static void nv_event(cmdarg_T *cap)
 {
diff --git a/src/nvim/terminal.c b/src/nvim/terminal.c
index ea3617098b..b916660024 100644
--- a/src/nvim/terminal.c
+++ b/src/nvim/terminal.c
@@ -748,6 +748,10 @@ static int terminal_execute(VimState *state, int key)
     }
     break;
 
+  case K_PASTE_START:
+    paste_repeat(1);
+    break;
+
   case K_EVENT:
     // We cannot let an event free the terminal yet. It is still needed.
     s->term->refcount++;
diff --git a/test/functional/api/vim_spec.lua b/test/functional/api/vim_spec.lua
index 71703c9b05..ae61e50624 100644
--- a/test/functional/api/vim_spec.lua
+++ b/test/functional/api/vim_spec.lua
@@ -1301,8 +1301,62 @@ describe('API', function()
     end)
     it('crlf=false does not break lines at CR, CRLF', function()
       api.nvim_paste('line 1\r\n\r\rline 2\nline 3\rline 4\r', false, -1)
-      expect('line 1\r\n\r\rline 2\nline 3\rline 4\r')
+      local expected = 'line 1\r\n\r\rline 2\nline 3\rline 4\r'
+      expect(expected)
       eq({ 0, 3, 14, 0 }, fn.getpos('.'))
+      feed('u') -- Undo.
+      expect('')
+      feed('.') -- Dot-repeat.
+      expect(expected)
+    end)
+    describe('repeating a paste via redo/recording', function()
+      -- Test with indent and control chars and multibyte chars containing 0x80 bytes
+      local text = dedent(([[
+      foo
+        bar
+          baz
+      !!!%s!!!%s!!!%s!!!
+      最…倒…倀…
+      ]]):format('\0', '\2\3\6\21\22\23\24\27', '\127'))
+      before_each(function()
+        api.nvim_set_option_value('autoindent', true, {})
+      end)
+      local function test_paste_repeat_normal_insert(is_insert)
+        feed('qr' .. (is_insert and 'i' or ''))
+        eq('r', fn.reg_recording())
+        api.nvim_paste(text, true, -1)
+        feed(is_insert and '<Esc>' or '')
+        expect(text)
+        feed('.')
+        expect(text:rep(2))
+        feed('q')
+        eq('', fn.reg_recording())
+        feed('3.')
+        expect(text:rep(5))
+        feed('2@r')
+        expect(text:rep(9))
+      end
+      it('works in Normal mode', function()
+        test_paste_repeat_normal_insert(false)
+      end)
+      it('works in Insert mode', function()
+        test_paste_repeat_normal_insert(true)
+      end)
+      local function test_paste_repeat_visual_select(is_select)
+        insert(('xxx\n'):rep(5))
+        feed('ggqr' .. (is_select and 'gH' or 'V'))
+        api.nvim_paste(text, true, -1)
+        feed('q')
+        expect(text .. ('xxx\n'):rep(4))
+        feed('2@r')
+        expect(text:rep(3) .. ('xxx\n'):rep(2))
+      end
+      it('works in Visual mode (recording only)', function()
+        test_paste_repeat_visual_select(false)
+      end)
+      it('works in Select mode (recording only)', function()
+        test_paste_repeat_visual_select(true)
+      end)
     end)
     it('vim.paste() failure', function()
       api.nvim_exec_lua('vim.paste = (function(lines, phase) error("fake fail") end)', {})
diff --git a/test/functional/terminal/tui_spec.lua b/test/functional/terminal/tui_spec.lua
index 3e837e796d..a8a664a568 100644
--- a/test/functional/terminal/tui_spec.lua
+++ b/test/functional/terminal/tui_spec.lua
@@ -1106,7 +1106,7 @@ describe('TUI', function()
     screen:expect(expected_grid1)
     -- Dot-repeat/redo.
     feed_data('.')
-    screen:expect([[
+    local expected_grid2 = [[
       ESC:{6:^[} / CR:                                      |
       xline 1                                           |
       ESC:{6:^[} / CR:                                      |
@@ -1114,7 +1114,8 @@ describe('TUI', function()
       {5:[No Name] [+]                   5,1            Bot}|
                                                         |
       {3:-- TERMINAL --}                                    |
-    ]])
+    ]]
+    screen:expect(expected_grid2)
     -- Undo.
     feed_data('u')
     expect_child_buf_lines(expected_crlf)
@@ -1128,6 +1129,14 @@ describe('TUI', function()
     feed_data('\027[200~' .. table.concat(expected_lf, '\r\n') .. '\027[201~')
     screen:expect(expected_grid1)
     expect_child_buf_lines(expected_crlf)
+    -- Dot-repeat/redo.
+    feed_data('.')
+    screen:expect(expected_grid2)
+    -- Undo.
+    feed_data('u')
+    expect_child_buf_lines(expected_crlf)
+    feed_data('u')
+    expect_child_buf_lines({ '' })
   end)
 
   it('paste: cmdline-mode inserts 1 line', function()