[lo-fi] try to maintain the position of lines on the display

Fixes #815

src/listview_curses.cc

@@ -205,10 +205,10 @@ listview_curses::do_update()
             width = std::min((unsigned long) this->vc_width, width);
         }
 
-        wrap_width = width
-            - (this->lv_word_wrap            ? 1
-                   : this->lv_show_scrollbar ? 1
-                                             : 0);
+        wrap_width = width;
+        if (this->lv_show_scrollbar) {
+            wrap_width -= 1;
+        }
 
         size_t row_count = this->get_inner_height();
         row = this->lv_top;
@@ -231,15 +231,16 @@ listview_curses::do_update()
                 overlay_line.clear();
                 ++y;
             } else if (row < (int) row_count) {
-                attr_line_t& al = rows[row - this->lv_top];
+                auto& al = rows[row - this->lv_top];
 
+                size_t remaining = 0;
                 do {
-                    mvwattrline(this->lv_window,
-                                y,
-                                this->lv_x,
-                                al,
-                                lr,
-                                this->vc_default_role);
+                    remaining = mvwattrline(this->lv_window,
+                                            y,
+                                            this->lv_x,
+                                            al,
+                                            lr,
+                                            this->vc_default_role);
                     if (this->lv_word_wrap) {
                         mvwhline(this->lv_window,
                                  y,
@@ -250,8 +251,7 @@ listview_curses::do_update()
                     lr.lr_start += wrap_width;
                     lr.lr_end += wrap_width;
                     ++y;
-                } while (this->lv_word_wrap && y < bottom
-                         && lr.lr_start < (int) al.length());
+                } while (this->lv_word_wrap && y < bottom && remaining > 0);
                 ++row;
             } else {
                 wattr_set(this->lv_window,

src/lnav.cc

@@ -1212,7 +1212,7 @@ looper()
             lnav_data.ld_views[lpc].set_window(lnav_data.ld_window);
             lnav_data.ld_views[lpc].set_y(2);
             lnav_data.ld_views[lpc].set_height(
-                vis_line_t(-(rlc->get_height() + 1)));
+                vis_line_t(-(rlc->get_height() + 3)));
             lnav_data.ld_views[lpc].set_scroll_action(sb);
             lnav_data.ld_views[lpc].set_search_action(update_hits);
             lnav_data.ld_views[lpc].tc_state_event_handler = event_handler;

src/lnav_commands.cc

@@ -1168,7 +1168,9 @@ com_save_to(exec_context& ec,
             bottom = tc->get_inner_height() - 1_vl;
         }
         auto y = 0_vl;
+        auto wrapped_count = 0_vl;
         std::vector<attr_line_t> rows(bottom - top + 1);
+        auto dim = tc->get_dimensions();
         attr_line_t ov_al;
 
         auto* los = tc->get_overlay_source();
@@ -1181,6 +1183,7 @@ com_save_to(exec_context& ec,
                 write_line_to(outfile, ov_al);
                 ++y;
             }
+            wrapped_count += vis_line_t((al.length() - 1) / (dim.second - 2));
             write_line_to(outfile, al);
 
             line_count += 1;
@@ -1198,12 +1201,16 @@ com_save_to(exec_context& ec,
 
         tc->set_word_wrap(wrapped);
         tc->set_top(orig_top);
+
+        if (!(lnav_data.ld_flags & LNF_HEADLESS)) {
+            while (y + wrapped_count < dim.first + 2_vl) {
+                fmt::print(outfile, FMT_STRING("\n"));
+                ++y;
+            }
+        }
     } else if (args[0] == "write-raw-to") {
         if (tc == &lnav_data.ld_views[LNV_DB]) {
-            std::vector<std::vector<const char*>>::iterator row_iter;
-            std::vector<const char*>::iterator iter;
-
-            for (row_iter = dls.dls_rows.begin();
+            for (auto row_iter = dls.dls_rows.begin();
                  row_iter != dls.dls_rows.end();
                  ++row_iter)
             {
@@ -1213,9 +1220,8 @@ com_save_to(exec_context& ec,
                     break;
                 }
 
-                for (iter = row_iter->begin(); iter != row_iter->end(); ++iter)
-                {
-                    fputs(*iter, outfile);
+                for (auto& iter : *row_iter) {
+                    fputs(iter, outfile);
                 }
                 fprintf(outfile, "\n");
 
@@ -1734,7 +1740,8 @@ com_filter(exec_context& ec,
                 "filters with a pipe symbol (e.g. foo|bar)");
         }
 
-        auto compile_res = pcrepp::shared_from_str(args[1], PCRE_CASELESS | PCRE_UTF8);
+        auto compile_res
+            = pcrepp::shared_from_str(args[1], PCRE_CASELESS | PCRE_UTF8);
 
         if (compile_res.isErr()) {
             auto ce = compile_res.unwrapErr();
@@ -2156,8 +2163,8 @@ com_create_search_table(exec_context& ec,
             regex = lnav_data.ld_views[LNV_LOG].get_current_search();
         }
 
-        auto re_res
-            = pcrepp::shared_from_str(regex, log_search_table::pattern_options());
+        auto re_res = pcrepp::shared_from_str(
+            regex, log_search_table::pattern_options());
 
         if (re_res.isErr()) {
             auto re_err = re_res.unwrapErr();
@@ -5471,10 +5478,10 @@ readline_context::command_t STD_COMMANDS[] = {
          .with_parameter(help_text("path", "The path to the file to write"))
          .with_tags({"io", "scripting"})},
     {"rebuild",
-    com_rebuild,
-    help_text(":rebuild")
-    .with_summary("Forcefully rebuild file indexes")
-    .with_tags({"scripting"})},
+     com_rebuild,
+     help_text(":rebuild")
+         .with_summary("Forcefully rebuild file indexes")
+         .with_tags({"scripting"})},
     {"set-min-log-level",
      com_set_min_log_level,
 
@@ -5599,9 +5606,8 @@ init_lnav_commands(readline_context::command_map_t& cmd_map)
         cmd_map["add-test"] = &add_test;
     }
     if (getenv("lnav_test") != nullptr) {
-        static readline_context::command_t
-            shexec(com_shexec), poll_now(com_poll_now),
-            test_comment(com_test_comment);
+        static readline_context::command_t shexec(com_shexec),
+            poll_now(com_poll_now), test_comment(com_test_comment);
 
         cmd_map["shexec"] = &shexec;
         cmd_map["poll-now"] = &poll_now;

src/view_curses.cc

@@ -125,7 +125,7 @@ view_curses::awaiting_user_input()
     }
 }
 
-void
+size_t
 view_curses::mvwattrline(WINDOW* window,
                          int y,
                          int x,
@@ -148,15 +148,21 @@ view_curses::mvwattrline(WINDOW* window,
     bool has_fg = false;
     short* bg_color = (short*) alloca(line_width_chars * sizeof(short));
     bool has_bg = false;
-    line_range lr_bytes{lr_chars.lr_start, lr_chars.lr_end};
+    line_range lr_bytes;
     int char_index = 0;
 
     for (size_t lpc = 0; lpc < line.size(); lpc++) {
         int exp_start_index = expanded_line.size();
         auto ch = static_cast<unsigned char>(line[lpc]);
 
+        if (char_index == lr_chars.lr_start) {
+            lr_bytes.lr_start = exp_start_index;
+        } else if (char_index == lr_chars.lr_end) {
+            lr_bytes.lr_end = exp_start_index;
+        }
+
         switch (ch) {
-            case '\t':
+            case '\t': {
                 do {
                     expanded_line.push_back(' ');
                     char_index += 1;
@@ -164,6 +170,7 @@ view_curses::mvwattrline(WINDOW* window,
                 utf_adjustments.emplace_back(
                     lpc, expanded_line.size() - exp_start_index - 1);
                 break;
+            }
 
             case '\r':
             case '\n':
@@ -183,12 +190,14 @@ view_curses::mvwattrline(WINDOW* window,
 
                     expanded_line.push_back(ch);
                     if (offset) {
+#if 0
                         if (char_index < lr_chars.lr_start) {
                             lr_bytes.lr_start += abs(offset);
                         }
                         if (char_index < lr_chars.lr_end) {
                             lr_bytes.lr_end += abs(offset);
                         }
+#endif
                         exp_offset += offset;
                         utf_adjustments.emplace_back(lpc, offset);
                         for (; offset && (lpc + 1) < line.size();
@@ -203,6 +212,10 @@ view_curses::mvwattrline(WINDOW* window,
             }
         }
     }
+    if (lr_bytes.lr_end == -1) {
+        lr_bytes.lr_end = expanded_line.size();
+    }
+    size_t retval = expanded_line.size() - lr_bytes.lr_end;
 
     full_line = expanded_line;
 
@@ -218,8 +231,8 @@ view_curses::mvwattrline(WINDOW* window,
         waddnstr(
             window, &full_line.c_str()[lr_bytes.lr_start], lr_bytes.length());
     }
-    if (lr_bytes.lr_end > (int) full_line.size()) {
-        whline(window, ' ', lr_bytes.lr_end - (full_line.size() + exp_offset));
+    if (lr_chars.lr_end > char_index) {
+        whline(window, ' ', lr_chars.lr_end - char_index);
     }
 
     std::stable_sort(sa.begin(), sa.end());
@@ -421,6 +434,8 @@ view_curses::mvwattrline(WINDOW* window,
         }
         mvwadd_wchnstr(window, y, x, row_ch, ch_width);
     }
+
+    return retval;
 }
 
 constexpr short view_colors::MATCH_COLOR_DEFAULT;

src/view_curses.hh

@@ -375,12 +375,12 @@ public:
 
     static void awaiting_user_input();
 
-    static void mvwattrline(WINDOW* window,
-                            int y,
-                            int x,
-                            attr_line_t& al,
-                            const struct line_range& lr,
-                            role_t base_role = role_t::VCR_TEXT);
+    static size_t mvwattrline(WINDOW* window,
+                              int y,
+                              int x,
+                              attr_line_t& al,
+                              const struct line_range& lr,
+                              role_t base_role = role_t::VCR_TEXT);
 
 protected:
     bool vc_visible{true};