[view] add selection column to lnav_views

related to #1149

src/listview_curses.cc

@@ -512,12 +512,15 @@ listview_curses::set_top(vis_line_t top, bool suppress_flash)
             alerter::singleton().chime("invalid top");
         }
     } else if (this->lv_top != top) {
+        auto old_top = this->lv_top;
         this->lv_top = top;
         if (this->lv_selectable) {
             if (this->lv_selection < 0_vl) {
             } else if (this->lv_selection < top) {
-                this->set_selection(top);
+                auto sel_diff = this->lv_selection - old_top;
+                this->set_selection(top + sel_diff);
             } else {
+                auto sel_diff = this->lv_selection - old_top;
                 auto bot = this->get_bottom();
                 unsigned long width;
                 vis_line_t height;
@@ -526,7 +529,7 @@ listview_curses::set_top(vis_line_t top, bool suppress_flash)
 
                 if (bot != -1_vl && (bot - top) >= (height - 1)) {
                     if (this->lv_selection > (bot - this->lv_tail_space)) {
-                        this->set_selection(bot - this->lv_tail_space);
+                        this->set_selection(top + sel_diff);
                     }
                 }
             }

src/views_vtab.cc

@@ -190,7 +190,8 @@ CREATE TABLE lnav_views (
     search TEXT,            -- The text to search for in the view.
     filtering INTEGER,      -- Indicates if the view is applying filters.
     movement TEXT,          -- The movement mode, either 'top' or 'cursor'.
-    top_meta TEXT           -- A JSON object that contains metadata related to the top line in the view.
+    top_meta TEXT,          -- A JSON object that contains metadata related to the top line in the view.
+    selection INTEGER       -- The number of the line that is focused for selection.
 );
 )";
 
@@ -340,6 +341,9 @@ CREATE TABLE lnav_views (
                 }
                 break;
             }
+            case 12:
+                sqlite3_result_int(ctx, (int) tc.get_selection());
+                break;
         }
 
         return SQLITE_OK;
@@ -372,7 +376,8 @@ CREATE TABLE lnav_views (
                    const char* search,
                    bool do_filtering,
                    string_fragment movement,
-                   const char* top_meta)
+                   const char* top_meta,
+                   int64_t selection)
     {
         auto& tc = lnav_data.ld_views[index];
         auto* time_source
@@ -399,6 +404,9 @@ CREATE TABLE lnav_views (
                 return SQLITE_ERROR;
             }
         }
+        if (tc.is_selectable() && tc.get_selection() != selection) {
+            tc.set_selection(vis_line_t(selection));
+        }
         if (top_meta != nullptr) {
             static const intern_string_t SQL_SRC
                 = intern_string::lookup("top_meta");

test/listview_output_cursor.6

@@ -6,7 +6,7 @@ S  -1 ┋
 A      └ normal
 CSI Reset Replace mode
 CSI Erase all
-S   1 ┋9                                                                              x┋
+S   1 ┋+9                                                                             x┋
 A                                                                                     └┛ alt
 S   2 ┋10                                                                             x┋
 A                                                                                     └┛ alt
@@ -22,7 +22,7 @@ S   7 ┋15
 A                                                                                     └┛ alt
 S   8 ┋16                                                                             x┋
 A                                                                                     └┛ alt
-S   9 ┋+17                                                                            x┋
+S   9 ┋17                                                                             x┋
 A                                                                                     └┛ alt
 S  10 ┋18                                                                             x┋
 A                                                                                     └┛ alt