Optimize line iterator

README.md

@@ -6,28 +6,55 @@ A TUI IDE.
 
 # TODO
 
+- [ ] Add tab/untab with [,<] and [.>]
+- [ ] Add something that works like `p` but doesnt move cursor.
+- [ ] Fix the fact that hooks arent updated when a line is deleted/added.
+- [ ] also use this sorta rules apart from previous lines indentation for the indentor.
+    - if previous line ends with { or similar → indent +1 
+        - (i.e. just check the last line that is not string or comment or empty)
+    - language-specific rules later if you want
+    - ignore comments that dedent etc. - anything else should be handled by LSP.
+- [ ] Fix bug where clicking outside eof sets to top.
+- [ ] Add this thing where select at end of screen scrolls down. (and vice versa)
+- [ ] Add a virtual text support (text that is rendered in the editor but not in the actual text)
+    - Add a whitespace highlighter (nerd font). for spaces and tabs at start/end of line.
+- [ ] Add support for LSP & autocomplete / snippets.
+    - First research
+        - `textDocument/documentHighlight` - for highlighting stuff (probably tree-sitter is enough)
+        - `textDocument/selectionRange` //
+        - `textDocument/completion` - Obviously
+        - `textDocument/onTypeFormatting` - seems promising for auto formatting (indentation etc)
+        - `textDocument/inlayHint` & `textDocument/inlineHint` & `textDocument/codeLens`
+        - `textDocument/formatting` & `textDocument/rangeFormatting`
+        - `textDocument/semanticTokens/*` (probably tree-sitter is enough)
+        - `textDocument/linkedEditingRange` - probably useful
+        - `textDocument/foldingRange` - i will never use this for folding but it might be useful for other things.
+        - `textDocument/rename` & `textDocument/prepareRename` - probably useful
+        - And a lot more (just go through each for `clangd` and then expand to say `solargraph`).
+    - Make a universal plug for lsp. So focus more on making a general purpose solid communication interface. Instead of something specific.
+        - With a 4ish pass system. (more like each returned value from the lsp is used in 4 ways)
+            1. One for stuff like jump to x position. or rename symbol x to y. (stuff that explicitly requires user request to do something)
+                - Maybe even hover goes here
+            2. One for stuff that only affects highlighting and styles . like symbol highlighting etc.
+            3. One for Warnings/errors and inlay hints etc. (stuff that adds virtual text to the editor)
+            4. One for fromatting and stuff like that. (stuff that edits the buffer text)
+- [ ] Add snippets from wherever i get them. (like luasnip or vsnip)
 - [ ] Add support for virtual cursor where edits apply at all the places.
 - [ ] Add alt + click to set multiple cursors.
 - [ ] Add search / replace along with search / virtual cursors are searched pos.
 - [ ] Add support for undo/redo.
 - [ ] Add `.scm` files for all the supported languages. (2/14) Done.
 - [ ] Add splash screen / minigame jumping.
-- [ ] Add support for LSP & autocomplete / snippets.
 - [ ] Add codeium/copilot support.
 - [ ] Normalize / validate unicode on file open.
 - [ ] Add git stuff.
+- [ ] Add SQL support. (viewer and basic editor)
+- [ ] Add color picker/palette for hex or other css colors.
 - [ ] Fix bug where alt+up at eof adds extra line.
-- [ ] Think about how i would keep fold states sensical if i added code prettying.
+- [ ] Think about how i would keep fold states sensical if i added code prettying/formatting.
-
+- [ ] Use tree-sitter to get the node path of the current node under cursor and add an indicator bar. 
-- [ ] Retry get proper blocks from tree-sitter.
+    - (possibly with a picker to jump to any node)
-    - And use it for full block selection (including inline ones).
+- [ ] Add the highlight of block edges when cursor is on a bracket (or in). (prolly from lsp)
-    - And for indenting.
-    - And highlighting block edges etc.
-- [ ] Add feature where doing enter uses tree-sitter to add newline with indentation.
-    - it should also put stuff like `}` on the next line.
-- [ ] Add the highlight of block edges when cursor is on a bracket (or in).
 - [ ] Add this thing where selection double click on a bracket selects whole block.
     - (only on the first time) and sets mode to `WORD`.
-- [ ] Redo folding system and its relation to move_line_* functions.
+- [ ] Redo folding system and its relation to move_line_* functions. (Currently its a mess)
-- [ ] Also try regex based indentation.
-- [ ] And indentation based blocks

include/knot.h

@@ -27,6 +27,8 @@ typedef struct LineIterator {
   uint8_t top;
   uint32_t offset;
   Knot *stack[64];
+  char *buffer;
+  size_t capacity;
 } LineIterator;
 
 typedef struct LeafIterator {

src/editor.cc

@@ -92,12 +92,12 @@ void render_editor(Editor *editor) {
       case LINE:
         LineIterator *it = begin_l_iter(editor->root, editor->selection.row);
         char *line = next_line(it, &line_len);
-        free(it);
         if (!line)
           return;
         if (line_len > 0 && line[line_len - 1] == '\n')
           line_len--;
-        free(line);
+        free(it->buffer);
+        free(it);
         end = {editor->selection.row, line_len};
         break;
       }
@@ -148,7 +148,6 @@ void render_editor(Editor *editor) {
         if (line_len > 0 && line[line_len - 1] == '\n')
           global_byte_offset--;
         global_byte_offset++;
-        free(line);
         line_index++;
       }
       continue;
@@ -179,7 +178,8 @@ void render_editor(Editor *editor) {
         update(editor->position.row + rendered_rows, editor->position.col, hook,
                0xAAAAAA, 0, 0);
         char buf[16];
-        int len = snprintf(buf, sizeof(buf), "%*u", numlen - 3, line_index + 1);
+        int len =
+            snprintf(buf, sizeof(buf), "%*u ", numlen - 3, line_index + 1);
         uint32_t num_color =
             editor->cursor.row == line_index ? 0xFFFFFF : 0x555555;
         for (int i = 0; i < len; i++)
@@ -298,7 +298,6 @@ void render_editor(Editor *editor) {
     }
     global_byte_offset += line_len + 1;
     line_index++;
-    free(line);
   }
   if (cursor.row != UINT32_MAX && cursor.col != UINT32_MAX) {
     int type = 0;
@@ -322,5 +321,6 @@ void render_editor(Editor *editor) {
              " ", 0xFFFFFF, 0, 0);
     rendered_rows++;
   }
+  free(it->buffer);
   free(it);
 }

src/editor_ctrl.cc

@@ -48,7 +48,6 @@ void word_boundaries_exclusive(Editor *editor, Coord coord, uint32_t *prev_col,
     return;
   uint32_t line_len;
   char *line = next_line(it, &line_len);
-  free(it);
   if (!line)
     return;
   if (line_len && line[line_len - 1] == '\n')
@@ -62,7 +61,8 @@ void word_boundaries_exclusive(Editor *editor, Coord coord, uint32_t *prev_col,
     *prev_col = left;
   if (next_col)
     *next_col = right;
-  free(line);
+  free(it->buffer);
+  free(it);
 }
 
 uint32_t word_jump_right(const char *line, size_t len, uint32_t pos) {
@@ -99,7 +99,6 @@ void word_boundaries(Editor *editor, Coord coord, uint32_t *prev_col,
     return;
   uint32_t line_len;
   char *line = next_line(it, &line_len);
-  free(it);
   if (!line)
     return;
   if (line_len && line[line_len - 1] == '\n')
@@ -117,7 +116,8 @@ void word_boundaries(Editor *editor, Coord coord, uint32_t *prev_col,
     *prev_clusters = count_clusters(line, line_len, left, col);
   if (next_clusters)
     *next_clusters = count_clusters(line, line_len, col, right);
-  free(line);
+  free(it->buffer);
+  free(it);
 }
 
 Coord editor_hit_test(Editor *editor, uint32_t x, uint32_t y) {
@@ -140,6 +140,7 @@ Coord editor_hit_test(Editor *editor, uint32_t x, uint32_t y) {
     const Fold *fold = fold_for_line(editor->folds, line_index);
     if (fold) {
       if (visual_row == target_visual_row) {
+        free(it->buffer);
         free(it);
         if (is_gutter_click) {
           remove_fold(editor, fold->start);
@@ -152,7 +153,6 @@ Coord editor_hit_test(Editor *editor, uint32_t x, uint32_t y) {
         char *l = next_line(it, nullptr);
         if (!l)
           break;
-        free(l);
         line_index++;
       }
       continue;
@@ -177,7 +177,7 @@ Coord editor_hit_test(Editor *editor, uint32_t x, uint32_t y) {
         if (col + w > render_width)
           break;
         if (visual_row == target_visual_row && x < col + w) {
-          free(line);
+          free(it->buffer);
           free(it);
           return {line_index, offset + advance};
         }
@@ -187,7 +187,7 @@ Coord editor_hit_test(Editor *editor, uint32_t x, uint32_t y) {
         col += w;
       }
       if (visual_row == target_visual_row) {
-        free(line);
+        free(it->buffer);
         free(it);
         return {line_index, last_good_offset};
       }
@@ -200,9 +200,9 @@ Coord editor_hit_test(Editor *editor, uint32_t x, uint32_t y) {
       if (line_len == 0)
         break;
     }
-    free(line);
     line_index++;
   }
+  free(it->buffer);
   free(it);
   return editor->scroll;
 }
@@ -215,16 +215,18 @@ Coord move_right_pure(Editor *editor, Coord cursor, uint32_t number) {
   uint32_t col = result.col;
   uint32_t line_len = 0;
   LineIterator *it = begin_l_iter(editor->root, row);
-  char *line = next_line(it, &line_len);
+  if (!it)
-  free(it);
-  if (!line)
     return result;
+  char *line = next_line(it, &line_len);
+  if (!line) {
+    free(it->buffer);
+    free(it);
+    return result;
+  }
   if (line_len > 0 && line[line_len - 1] == '\n')
     --line_len;
   while (number > 0) {
     if (col >= line_len) {
-      free(line);
-      line = nullptr;
       uint32_t next_row = row + 1;
       if (next_row >= editor->root->line_count) {
         col = line_len;
@@ -232,9 +234,7 @@ Coord move_right_pure(Editor *editor, Coord cursor, uint32_t number) {
       }
       row = next_row;
       col = 0;
-      it = begin_l_iter(editor->root, row);
       line = next_line(it, &line_len);
-      free(it);
       if (!line)
         break;
       if (line_len > 0 && line[line_len - 1] == '\n')
@@ -248,8 +248,8 @@ Coord move_right_pure(Editor *editor, Coord cursor, uint32_t number) {
     }
     number--;
   }
-  if (line)
+  free(it->buffer);
-    free(line);
+  free(it);
   result.row = row;
   result.col = col;
   return result;
@@ -265,6 +265,7 @@ Coord move_left_pure(Editor *editor, Coord cursor, uint32_t number) {
   LineIterator *it = begin_l_iter(editor->root, row);
   char *line = next_line(it, &len);
   if (!line) {
+    free(it->buffer);
     free(it);
     return result;
   }
@@ -276,10 +277,9 @@ Coord move_left_pure(Editor *editor, Coord cursor, uint32_t number) {
       if (row == 0)
         break;
       if (iterator_ahead) {
-        free(prev_line(it, nullptr));
+        prev_line(it, nullptr);
         iterator_ahead = false;
       }
-      free(line);
       line = nullptr;
       row--;
       line = prev_line(it, &len);
@@ -301,8 +301,7 @@ Coord move_left_pure(Editor *editor, Coord cursor, uint32_t number) {
     }
     number--;
   }
-  if (line)
+  free(it->buffer);
-    free(line);
   free(it);
   result.row = row;
   result.col = col;
@@ -317,41 +316,58 @@ Coord move_right(Editor *editor, Coord cursor, uint32_t number) {
   uint32_t col = result.col;
   uint32_t line_len = 0;
   LineIterator *it = begin_l_iter(editor->root, row);
-  char *line = next_line(it, &line_len);
+  if (!it)
-  free(it);
-  if (!line)
     return result;
+  uint32_t target_row = next_unfolded_row(editor, row);
+  while (row < target_row) {
+    if (!next_line(it, &line_len)) {
+      free(it->buffer);
+      free(it);
+      return result;
+    }
+    ++row;
+  }
+  char *line = next_line(it, &line_len);
+  if (!line) {
+    free(it->buffer);
+    free(it);
+    return result;
+  }
   if (line_len > 0 && line[line_len - 1] == '\n')
     --line_len;
   while (number > 0) {
     if (col >= line_len) {
-      free(line);
-      line = nullptr;
       uint32_t next_row = next_unfolded_row(editor, row + 1);
       if (next_row >= editor->root->line_count) {
         col = line_len;
         break;
       }
-      row = next_row;
+      while (row < next_row) {
-      col = 0;
-      it = begin_l_iter(editor->root, row);
         line = next_line(it, &line_len);
+        if (!line) {
+          free(it->buffer);
           free(it);
-      if (!line)
+          result.row = row;
-        break;
+          result.col = col;
+          return result;
+        }
+        ++row;
+      }
+      col = 0;
       if (line_len > 0 && line[line_len - 1] == '\n')
         --line_len;
+      continue;
     } else {
       uint32_t inc =
           grapheme_next_character_break_utf8(line + col, line_len - col);
       if (inc == 0)
         break;
       col += inc;
+      --number;
     }
-    number--;
   }
-  if (line)
+  free(it->buffer);
-    free(line);
+  free(it);
   result.row = row;
   result.col = col;
   return result;
@@ -367,6 +383,7 @@ Coord move_left(Editor *editor, Coord cursor, uint32_t number) {
   LineIterator *it = begin_l_iter(editor->root, row);
   char *line = next_line(it, &len);
   if (!line) {
+    free(it->buffer);
     free(it);
     return result;
   }
@@ -378,10 +395,9 @@ Coord move_left(Editor *editor, Coord cursor, uint32_t number) {
       if (row == 0)
         break;
       if (iterator_ahead) {
-        free(prev_line(it, nullptr));
+        prev_line(it, nullptr);
         iterator_ahead = false;
       }
-      free(line);
       line = nullptr;
       while (row > 0) {
         row--;
@@ -391,14 +407,10 @@ Coord move_left(Editor *editor, Coord cursor, uint32_t number) {
         const Fold *fold = fold_for_line(editor->folds, row);
         if (fold) {
           while (line && row > fold->start) {
-            free(line);
             line = prev_line(it, &len);
             row--;
           }
-          if (line) {
-            free(line);
           line = nullptr;
-          }
           continue;
         }
         break;
@@ -421,8 +433,7 @@ Coord move_left(Editor *editor, Coord cursor, uint32_t number) {
     }
     number--;
   }
-  if (line)
+  free(it->buffer);
-    free(line);
   free(it);
   result.row = row;
   result.col = col;
@@ -435,14 +446,14 @@ void cursor_down(Editor *editor, uint32_t number) {
   uint32_t len;
   LineIterator *it = begin_l_iter(editor->root, editor->cursor.row);
   char *line_content = next_line(it, &len);
-  free(it);
   if (line_content == nullptr)
     return;
   if (editor->cursor_preffered == UINT32_MAX)
     editor->cursor_preffered =
         get_visual_col_from_bytes(line_content, len, editor->cursor.col);
   uint32_t visual_col = editor->cursor_preffered;
-  free(line_content);
+  free(it->buffer);
+  free(it);
   uint32_t target_row = editor->cursor.row;
   while (number > 0 && target_row < editor->root->line_count - 1) {
     target_row = next_unfolded_row(editor, target_row + 1);
@@ -454,14 +465,14 @@ void cursor_down(Editor *editor, uint32_t number) {
   }
   it = begin_l_iter(editor->root, target_row);
   line_content = next_line(it, &len);
-  free(it);
   if (!line_content)
     return;
   if (len > 0 && line_content[len - 1] == '\n')
     --len;
   editor->cursor.row = target_row;
   editor->cursor.col = get_bytes_from_visual_col(line_content, len, visual_col);
-  free(line_content);
+  free(it->buffer);
+  free(it);
 }
 
 void cursor_up(Editor *editor, uint32_t number) {
@@ -470,14 +481,14 @@ void cursor_up(Editor *editor, uint32_t number) {
   uint32_t len;
   LineIterator *it = begin_l_iter(editor->root, editor->cursor.row);
   char *line_content = next_line(it, &len);
-  free(it);
   if (!line_content)
     return;
   if (editor->cursor_preffered == UINT32_MAX)
     editor->cursor_preffered =
         get_visual_col_from_bytes(line_content, len, editor->cursor.col);
   uint32_t visual_col = editor->cursor_preffered;
-  free(line_content);
+  free(it->buffer);
+  free(it);
   uint32_t target_row = editor->cursor.row;
   while (number > 0 && target_row > 0) {
     target_row = prev_unfolded_row(editor, target_row - 1);
@@ -489,18 +500,18 @@ void cursor_up(Editor *editor, uint32_t number) {
   }
   it = begin_l_iter(editor->root, target_row);
   line_content = next_line(it, &len);
-  free(it);
   if (line_content) {
     if (len > 0 && line_content[len - 1] == '\n')
       --len;
     editor->cursor.row = target_row;
     editor->cursor.col =
         get_bytes_from_visual_col(line_content, len, visual_col);
-    free(line_content);
   } else {
     editor->cursor.row = 0;
     editor->cursor.col = 0;
   }
+  free(it->buffer);
+  free(it);
 }
 
 void cursor_right(Editor *editor, uint32_t number) {
@@ -525,7 +536,6 @@ void move_line_up(Editor *editor) {
     std::shared_lock lock(editor->knot_mtx);
     LineIterator *it = begin_l_iter(editor->root, editor->cursor.row);
     char *line = next_line(it, &line_len);
-    free(it);
     if (!line) {
       lock.unlock();
       return;
@@ -543,7 +553,8 @@ void move_line_up(Editor *editor) {
     edit_erase(editor, {cursor.row, 0}, -1);
     edit_insert(editor, {cursor.row - up_by, 0}, (char *)"\n", 1);
     edit_insert(editor, {cursor.row - up_by, 0}, line, line_len);
-    free(line);
+    free(it->buffer);
+    free(it);
     editor->cursor = {cursor.row - up_by, cursor.col};
   } else if (mode == SELECT) {
     uint32_t start_row = MIN(editor->cursor.row, editor->selection.row);
@@ -576,7 +587,6 @@ void move_line_down(Editor *editor) {
     std::shared_lock lock(editor->knot_mtx);
     LineIterator *it = begin_l_iter(editor->root, editor->cursor.row);
     char *line = next_line(it, &line_len);
-    free(it);
     if (!line) {
       lock.unlock();
       return;
@@ -601,7 +611,8 @@ void move_line_down(Editor *editor) {
     edit_erase(editor, {cursor.row, 0}, -1);
     edit_insert(editor, {cursor.row + down_by, 0}, (char *)"\n", 1);
     edit_insert(editor, {cursor.row + down_by, 0}, line, line_len);
-    free(line);
+    free(it->buffer);
+    free(it);
     editor->cursor = {cursor.row + down_by, cursor.col};
   } else if (mode == SELECT) {
     if (editor->cursor.row >= editor->root->line_count - 1 ||
@@ -811,12 +822,13 @@ char *get_selection(Editor *editor, uint32_t *out_len) {
     case LINE:
       LineIterator *it = begin_l_iter(editor->root, editor->selection.row);
       char *line = next_line(it, &line_len);
-      free(it);
       if (!line)
         return nullptr;
       if (line_len > 0 && line[line_len - 1] == '\n')
         line_len--;
       end = {editor->selection.row, line_len};
+      free(it->buffer);
+      free(it);
       break;
     }
   }
@@ -877,13 +889,11 @@ bool add_fold(Editor *editor, uint32_t start, uint32_t end) {
   end = std::min(end, editor->root->line_count - 1);
   if (start == end)
     return false;
-
   Fold new_fold{start, end};
   auto &folds = editor->folds;
   auto it = std::lower_bound(
       folds.begin(), folds.end(), new_fold.start,
       [](const Fold &fold, uint32_t value) { return fold.start < value; });
-
   if (it != folds.begin()) {
     auto prev = std::prev(it);
     if (prev->end + 1 >= new_fold.start) {

src/editor_events.cc

@@ -70,12 +70,12 @@ void handle_editor_event(Editor *editor, KeyEvent event) {
             uint32_t line_len;
             LineIterator *it = begin_l_iter(editor->root, p.row);
             char *line = next_line(it, &line_len);
-            free(it);
             if (!line)
               return;
             if (line_len > 0 && line[line_len - 1] == '\n')
               line_len--;
-            free(line);
+            free(it->buffer);
+            free(it);
             editor->cursor = {p.row, line_len};
           }
           editor->cursor_preffered = UINT32_MAX;
@@ -115,12 +115,12 @@ void handle_editor_event(Editor *editor, KeyEvent event) {
           } else {
             LineIterator *it = begin_l_iter(editor->root, p.row);
             char *line = next_line(it, &line_len);
-            free(it);
             if (!line)
               return;
             if (line_len > 0 && line[line_len - 1] == '\n')
               line_len--;
-            free(line);
+            free(it->buffer);
+            free(it);
             editor->cursor = {p.row, line_len};
           }
           break;
@@ -216,9 +216,9 @@ void handle_editor_event(Editor *editor, KeyEvent event) {
             break;
           if (line_len > 0 && line[line_len - 1] == '\n')
             line_len--;
-          free(it);
           line_len = count_clusters(line, line_len, 0, line_len);
-          free(line);
+          free(it->buffer);
+          free(it);
           editor->cursor.col = line_len;
           editor->cursor_preffered = UINT32_MAX;
           mode = SELECT;
@@ -305,7 +305,6 @@ void handle_editor_event(Editor *editor, KeyEvent event) {
           uint32_t line_len = 0;
           LineIterator *it = begin_l_iter(editor->root, editor->cursor.row);
           char *line = next_line(it, &line_len);
-          free(it);
           bool closing = false;
           if (line && line_len > 0 && line[line_len - 1] == '\n')
             line_len--;
@@ -314,8 +313,9 @@ void handle_editor_event(Editor *editor, KeyEvent event) {
             if (indent == 0)
               indent = leading_indent(line, line_len);
             closing = closing_after_cursor(line, line_len, editor->cursor.col);
-            free(line);
           }
+          free(it->buffer);
+          free(it);
           uint32_t closing_indent =
               indent >= INDENT_WIDTH ? indent - INDENT_WIDTH : 0;
           std::string insert_text("\n");
@@ -366,10 +366,10 @@ void handle_editor_event(Editor *editor, KeyEvent event) {
           if (!it)
             return;
           char *line = next_line(it, nullptr);
-          free(it);
           char prev_char = line[prev_pos.col];
           char next_char = line[editor->cursor.col];
-          free(line);
+          free(it->buffer);
+          free(it);
           bool is_pair = (prev_char == '{' && next_char == '}') ||
                          (prev_char == '(' && next_char == ')') ||
                          (prev_char == '[' && next_char == ']') ||

src/editor_indents.cc

@@ -23,10 +23,10 @@ uint32_t get_indent(Editor *editor, Coord cursor) {
     if (line_len == 0)
       continue;
     uint32_t indent = leading_indent(line, line_len);
-    free(line);
-    free(it);
     return indent;
   }
+  free(it->buffer);
+  free(it);
   return 0;
 }
 

src/editor_scroll.cc

@@ -18,6 +18,7 @@ void scroll_up(Editor *editor, int32_t number) {
   uint32_t len;
   char *line = next_line(it, &len);
   if (!line) {
+    free(it->buffer);
     free(it);
     return;
   }
@@ -45,24 +46,24 @@ void scroll_up(Editor *editor, int32_t number) {
        ++it_seg) {
     if (--number == 0) {
       editor->scroll = {line_index, *it_seg};
-      free(line);
+      free(it->buffer);
       free(it);
       return;
     }
   }
-  free(line);
   line = prev_line(it, &len);
   if (!line) {
     editor->scroll = {0, 0};
+    free(it->buffer);
     free(it);
     return;
   }
-  free(line);
   do {
     line_index--;
     line = prev_line(it, &len);
     if (!line) {
       editor->scroll = {0, 0};
+      free(it->buffer);
       free(it);
       return;
     }
@@ -74,19 +75,20 @@ void scroll_up(Editor *editor, int32_t number) {
         line_index--;
         if (!line) {
           editor->scroll = {0, 0};
+          free(it->buffer);
           free(it);
           return;
         }
       }
       if (--number == 0) {
         editor->scroll = {fold->start, 0};
-        free(line);
+        free(it->buffer);
         free(it);
         return;
       }
-      free(line);
       if (fold->start == 0) {
         editor->scroll = {0, 0};
+        free(it->buffer);
         free(it);
         return;
       }
@@ -94,6 +96,7 @@ void scroll_up(Editor *editor, int32_t number) {
       line = prev_line(it, &len);
       if (!line) {
         editor->scroll = {0, 0};
+        free(it->buffer);
         free(it);
         return;
       }
@@ -121,13 +124,13 @@ void scroll_up(Editor *editor, int32_t number) {
          ++it_seg) {
       if (--number == 0) {
         editor->scroll = {line_index, *it_seg};
-        free(line);
+        free(it->buffer);
         free(it);
         return;
       }
     }
-    free(line);
   } while (number > 0);
+  free(it->buffer);
   free(it);
 }
 
@@ -168,10 +171,10 @@ void scroll_down(Editor *editor, uint32_t number) {
         char *line = next_line(it, nullptr);
         if (!line) {
           free(scroll_queue);
+          free(it->buffer);
           free(it);
           return;
         }
-        free(line);
         line_index++;
       }
       continue;
@@ -200,8 +203,8 @@ void scroll_down(Editor *editor, uint32_t number) {
       visual_seen++;
       if (visual_seen >= number + max_visual_lines) {
         editor->scroll = scroll_queue[q_head];
-        free(line);
         free(scroll_queue);
+        free(it->buffer);
         free(it);
         return;
       }
@@ -223,13 +226,13 @@ void scroll_down(Editor *editor, uint32_t number) {
       if (line_len == 0)
         break;
     }
-    free(line);
     line_index++;
   }
   if (q_size > 0) {
     uint32_t advance = (q_size > number) ? number : (q_size - 1);
     editor->scroll = scroll_queue[(q_head + advance) % max_visual_lines];
   }
+  free(it->buffer);
   free(it);
   free(scroll_queue);
 }
@@ -267,7 +270,6 @@ void ensure_cursor(Editor *editor) {
         char *line = next_line(it, nullptr);
         if (!line)
           break;
-        free(line);
         line_index++;
       }
       continue;
@@ -302,7 +304,7 @@ void ensure_cursor(Editor *editor) {
       if (line_index == editor->cursor.row) {
         if (editor->cursor.col >= offset &&
             editor->cursor.col <= offset + advance) {
-          free(line);
+          free(it->buffer);
           free(it);
           return;
         }
@@ -313,7 +315,6 @@ void ensure_cursor(Editor *editor) {
       if (line_len == 0)
         break;
     }
-    free(line);
     line_index++;
   }
   uint32_t last_real_row = last_visible.row;
@@ -325,6 +326,7 @@ void ensure_cursor(Editor *editor) {
   editor->cursor.row = last_visible.row;
   editor->cursor.col = last_visible.row == last_real_row ? last_visible.col : 0;
   editor->cursor_preffered = UINT32_MAX;
+  free(it->buffer);
   free(it);
 }
 
@@ -340,6 +342,7 @@ void ensure_scroll(Editor *editor) {
     uint32_t len;
     char *line = next_line(it, &len);
     if (!line) {
+      free(it->buffer);
       free(it);
       return;
     }
@@ -359,7 +362,7 @@ void ensure_scroll(Editor *editor) {
         if (editor->cursor.col > old_offset && editor->cursor.col <= offset) {
           editor->scroll.row = editor->cursor.row;
           editor->scroll.col = old_offset;
-          free(line);
+          free(it->buffer);
           free(it);
           return;
         }
@@ -368,7 +371,7 @@ void ensure_scroll(Editor *editor) {
       cols += width;
       offset += inc;
     }
-    free(line);
+    free(it->buffer);
     free(it);
     editor->scroll.row = editor->cursor.row;
     editor->scroll.col = (editor->cursor.col == 0) ? 0 : old_offset;
@@ -403,7 +406,6 @@ void ensure_scroll(Editor *editor) {
           char *line = next_line(it, nullptr);
           if (!line)
             break;
-          free(line);
           line_index++;
         }
         continue;
@@ -453,8 +455,8 @@ void ensure_scroll(Editor *editor) {
             cursor_found = true;
           if (cursor_found) {
             editor->scroll = scroll_queue[q_head];
-            free(line);
             free(scroll_queue);
+            free(it->buffer);
             free(it);
             return;
           }
@@ -464,9 +466,9 @@ void ensure_scroll(Editor *editor) {
           break;
       }
       line_index++;
-      free(line);
     }
     free(scroll_queue);
+    free(it->buffer);
     free(it);
   }
 }

src/knot.cc

@@ -471,6 +471,12 @@ LineIterator *begin_l_iter(Knot *root, uint32_t start_line) {
     return nullptr;
   it->top = 0;
   it->node = nullptr;
+  it->capacity = 128;
+  it->buffer = (char *)malloc(it->capacity);
+  if (!it->buffer) {
+    free(it);
+    return nullptr;
+  }
   if (start_line == 0) {
     it->offset = 0;
     while (root->left) {
@@ -499,6 +505,7 @@ LineIterator *begin_l_iter(Knot *root, uint32_t start_line) {
     }
   }
   if (!it->node) {
+    free(it->buffer);
     free(it);
     return nullptr;
   }
@@ -516,7 +523,7 @@ LineIterator *begin_l_iter(Knot *root, uint32_t start_line) {
       }
     }
   }
-  free(next_line(it, nullptr));
+  next_line(it, nullptr);
   return it;
 }
 
@@ -559,11 +566,7 @@ static void str_reverse(char *begin, char *end) {
 char *prev_line(LineIterator *it, uint32_t *out_len) {
   if (!it || !it->node)
     return nullptr;
-  size_t capacity = 128;
   size_t len = 0;
-  char *buffer = (char *)malloc(capacity);
-  if (!buffer)
-    return nullptr;
   while (it->node) {
     if (it->offset == 0) {
       iter_retreat_leaf(it);
@@ -578,25 +581,22 @@ char *prev_line(LineIterator *it, uint32_t *out_len) {
         break;
       }
     }
-    if (len + 1 >= capacity) {
+    if (len + 1 >= it->capacity) {
-      capacity *= 2;
+      it->capacity *= 2;
-      char *new_buf = (char *)realloc(buffer, capacity);
+      char *new_buf = (char *)realloc(it->buffer, it->capacity);
-      if (!new_buf) {
+      if (!new_buf)
-        free(buffer);
         return nullptr;
+      it->buffer = new_buf;
     }
-      buffer = new_buf;
+    it->buffer[len++] = c;
-    }
-    buffer[len++] = c;
   }
   if (len > 0) {
-    buffer[len] = '\0';
+    it->buffer[len] = '\0';
-    str_reverse(buffer, buffer + len - 1);
+    str_reverse(it->buffer, it->buffer + len - 1);
     if (out_len)
       *out_len = len;
-    return buffer;
+    return it->buffer;
   }
-  free(buffer);
   return nullptr;
 }
 
@@ -630,11 +630,7 @@ static inline void iter_advance_leaf(LineIterator *it) {
 char *next_line(LineIterator *it, uint32_t *out_len) {
   if (!it || !it->node)
     return nullptr;
-  size_t capacity = 128;
   size_t len = 0;
-  char *buffer = (char *)malloc(capacity);
-  if (!buffer)
-    return nullptr;
   while (it->node) {
     if (it->offset >= it->node->char_count) {
       iter_advance_leaf(it);
@@ -652,32 +648,30 @@ char *next_line(LineIterator *it, uint32_t *out_len) {
     } else {
       chunk_len = end - start;
     }
-    if (len + chunk_len + 1 > capacity) {
+    if (len + chunk_len + 1 > it->capacity) {
-      capacity = (capacity * 2) + chunk_len;
+      it->capacity = (it->capacity * 2) + chunk_len;
-      char *new_buf = (char *)realloc(buffer, capacity);
+      char *new_buf = (char *)realloc(it->buffer, it->capacity);
       if (!new_buf) {
-        free(buffer);
         return nullptr;
       }
-      buffer = new_buf;
+      it->buffer = new_buf;
     }
-    memcpy(buffer + len, start, chunk_len);
+    memcpy(it->buffer + len, start, chunk_len);
     len += chunk_len;
     it->offset += chunk_len;
     if (found_newline) {
-      buffer[len] = '\0';
+      it->buffer[len] = '\0';
       if (out_len)
         *out_len = len;
-      return buffer;
+      return it->buffer;
     }
   }
   if (len > 0) {
-    buffer[len] = '\0';
+    it->buffer[len] = '\0';
     if (out_len)
       *out_len = len;
-    return buffer;
+    return it->buffer;
   }
-  free(buffer);
   return nullptr;
 }