diff options
| -rw-r--r-- | buffer.c | 37 |
1 files changed, 36 insertions, 1 deletions
@@ -352,6 +352,36 @@ static Status buffer_edit_resize_prev_text(TextBuffer *buffer, BufferEdit *edit, return true; } +// does this edit actually make a difference to the buffer? +static bool buffer_edit_does_anything(TextBuffer *buffer, BufferEdit *edit) { + if (edit->prev_len == edit->new_len) { + // @OPTIMIZE: compare directly to the buffer contents, rather than extracting them temporarily + // into new_text. + char32_t *new_text = buffer_calloc(buffer, edit->new_len, sizeof *new_text); + if (new_text) { + size_t len = buffer_get_text_at_pos(buffer, edit->pos, new_text, edit->new_len); + assert(len == edit->new_len); + int cmp = memcmp(edit->prev_text, new_text, len * sizeof *new_text); + free(new_text); + return cmp != 0; + } else { + return false; + } + } else { + return true; + } +} + +// removes the last edit in the undo history if it doesn't do anything +static void buffer_remove_last_edit_if_empty(TextBuffer *buffer) { + if (buffer->store_undo_events) { + BufferEdit *last_edit = arr_lastp(buffer->undo_history); + if (last_edit && !buffer_edit_does_anything(buffer, last_edit)) { + arr_remove_last(buffer->undo_history); + } + } +} + // grow capacity of line to at least minimum_capacity // returns true if allocation was succesful static Status buffer_line_set_min_capacity(TextBuffer *buffer, Line *line, u32 minimum_capacity) { @@ -1134,6 +1164,9 @@ BufferPos buffer_insert_text_at_pos(TextBuffer *buffer, BufferPos pos, String32 } } + // We need to put this after the end so the emptiness-checking is done after the edit is made. + buffer_remove_last_edit_if_empty(buffer); + BufferPos b = {.line = line_idx, .index = index}; return b; } @@ -1252,6 +1285,7 @@ void buffer_delete_chars_at_pos(TextBuffer *buffer, BufferPos pos, i64 nchars_) // shrink length to get rid of that text last_edit->new_len -= new_text_del_end - new_text_del_start; } + } u32 line_idx = pos.line; @@ -1291,6 +1325,8 @@ void buffer_delete_chars_at_pos(TextBuffer *buffer, BufferPos pos, i64 nchars_) memmove(line->str + index, line->str + index + nchars, (size_t)(line->len - (nchars + index)) * sizeof(char32_t)); line->len -= nchars; } + + buffer_remove_last_edit_if_empty(buffer); } // Delete characters between the given buffer positions. @@ -1344,7 +1380,6 @@ void buffer_backspace_words_at_cursor(TextBuffer *buffer, i64 nwords) { } // puts the inverse edit into `inverse` -// @TODO: check if the edit actually did anything; return something based on that? static Status buffer_undo_edit(TextBuffer *buffer, BufferEdit const *edit, BufferEdit *inverse) { bool success = false; bool prev_store_undo_events = buffer->store_undo_events; |