[hotkey] the n/N keys will now move to the next cluster of search hits, up to a screenful

Defect Number:
    Reviewed By:
   Testing Done:

NEWS

@@ -21,7 +21,9 @@ lnav v0.8.2:
        users.
      * Pressing 'n'/'N' to move through the next/previous search hit will now
        skip adjacent lines, up to the vertical size of the view.  This should
-       make scanning through clusters of hits much faster.
+       make scanning through clusters of hits much faster.  Repeatedly
+       pressing these keys within a short time will also accelerate scanning
+       by moving the view at least a full page at a time.
 
      Breaking Changes:
      * The captured timestamp text in log files must fully match a known format

src/help.txt

@@ -196,7 +196,10 @@ Spatial Navigation
 
   e/E               Move to the next/previous error.
   w/W               Move to the next/previous warning.
-  n/N               Move to the next/previous search hit.
+  n/N               Move to the next/previous search hit.  When pressed
+                    repeatedly within a short time, the view will move at
+                    least a full page at a time instead of moving to the
+                    next hit.
   f/F               Move to the next/previous file.  In the log view, this
                     moves to the next line from a different file.  In the
                     text view, this rotates the view to the next file.

src/hotkeys.cc

@@ -332,21 +332,19 @@ void handle_paging_key(int ch)
         case 'n':
             moveto_cluster(&bookmark_vector<vis_line_t>::next,
                            &textview_curses::BM_SEARCH,
-                           tc->get_top());
+                           search_forward_from(tc));
             lnav_data.ld_bottom_source.grep_error("");
             lnav_data.ld_rl_view->set_alt_value(
-                    "Press '" ANSI_BOLD(">") "' or '" ANSI_BOLD("<")
-            "' to scroll horizontally to a search result");
+                "Press '" ANSI_BOLD(">") "' or '" ANSI_BOLD("<")
+                    "' to scroll horizontally to a search result");
             break;
 
         case 'N':
-            moveto_cluster(&bookmark_vector<vis_line_t>::prev,
-                           &textview_curses::BM_SEARCH,
-                           tc->get_top());
+            previous_cluster(&textview_curses::BM_SEARCH, tc);
             lnav_data.ld_bottom_source.grep_error("");
             lnav_data.ld_rl_view->set_alt_value(
-                    "Press '" ANSI_BOLD(">") "' or '" ANSI_BOLD("<")
-            "' to scroll horizontally to a search result");
+                "Press '" ANSI_BOLD(">") "' or '" ANSI_BOLD("<")
+                    "' to scroll horizontally to a search result");
             break;
 
         case 'y':

src/lnav.cc

@@ -892,8 +892,8 @@ vis_line_t next_cluster(
 }
 
 bool moveto_cluster(vis_line_t(bookmark_vector<vis_line_t>::*f) (vis_line_t),
-        bookmark_type_t *bt,
-        vis_line_t top)
+                    bookmark_type_t *bt,
+                    vis_line_t top)
 {
     textview_curses *tc = lnav_data.ld_view_stack.top();
     vis_line_t new_top;
@@ -909,6 +909,48 @@ bool moveto_cluster(vis_line_t(bookmark_vector<vis_line_t>::*f) (vis_line_t),
     return false;
 }
 
+void previous_cluster(bookmark_type_t *bt, textview_curses *tc)
+{
+    key_repeat_history &krh = lnav_data.ld_key_repeat_history;
+    vis_line_t height, new_top, initial_top = tc->get_top();
+    unsigned long width;
+
+    new_top = next_cluster(&bookmark_vector<vis_line_t>::prev,
+                           bt,
+                           initial_top);
+
+    tc->get_dimensions(height, width);
+    if (krh.krh_count > 1 &&
+        initial_top < (krh.krh_start_line - (1.5 * height)) &&
+        (initial_top - new_top) < height) {
+        bookmark_vector<vis_line_t> &bv = tc->get_bookmarks()[bt];
+        new_top = bv.next(std::max(vis_line_t(0), initial_top - height));
+    }
+
+    if (new_top != -1) {
+        tc->set_top(new_top);
+    }
+    else {
+        alerter::singleton().chime();
+    }
+}
+
+vis_line_t search_forward_from(textview_curses *tc)
+{
+    vis_line_t height, retval = tc->get_top();
+    key_repeat_history &krh = lnav_data.ld_key_repeat_history;
+    unsigned long width;
+
+    tc->get_dimensions(height, width);
+
+    if (krh.krh_count > 1 &&
+        retval > (krh.krh_start_line + (1.5 * height))) {
+        retval += vis_line_t(0.90 * height);
+    }
+
+    return retval;
+}
+
 static void handle_rl_key(int ch)
 {
     switch (ch) {
@@ -1898,6 +1940,10 @@ static void looper(void)
                             escape_index = 0;
                             continue;
                         }
+
+                        lnav_data.ld_key_repeat_history.update(
+                            ch, lnav_data.ld_view_stack.top()->get_top());
+
                         switch (ch) {
                         case CEOF:
                         case KEY_RESIZE:

src/lnav.hh

@@ -174,6 +174,40 @@ private:
     size_t ist_index;
 };
 
+struct key_repeat_history {
+    key_repeat_history()
+        : krh_key(0),
+          krh_count(0) {
+        this->krh_last_press_time.tv_sec = 0;
+        this->krh_last_press_time.tv_usec = 0;
+    }
+
+    int krh_key;
+    int krh_count;
+    vis_line_t krh_start_line;
+    struct timeval krh_last_press_time;
+
+    void update(int ch, vis_line_t top) {
+        struct timeval now, diff;
+
+        gettimeofday(&now, NULL);
+        timersub(&now, &this->krh_last_press_time, &diff);
+        if (diff.tv_sec >= 1 || diff.tv_usec > (750 * 1000)) {
+            this->krh_key = 0;
+            this->krh_count = 0;
+        }
+        this->krh_last_press_time = now;
+
+        if (this->krh_key == ch) {
+            this->krh_count += 1;
+        } else {
+            this->krh_key = ch;
+            this->krh_count = 1;
+            this->krh_start_line = top;
+        }
+    };
+};
+
 struct _lnav_data {
     std::string                             ld_session_id;
     time_t                                  ld_session_time;
@@ -264,6 +298,8 @@ struct _lnav_data {
     std::map<std::string, std::vector<script_metadata> > ld_scripts;
 
     int ld_fifo_counter;
+
+    struct key_repeat_history ld_key_repeat_history;
 };
 
 extern struct _lnav_data lnav_data;
@@ -298,7 +334,9 @@ vis_line_t next_cluster(
         bookmark_type_t *bt,
         vis_line_t top);
 bool moveto_cluster(vis_line_t(bookmark_vector<vis_line_t>::*f) (vis_line_t),
-        bookmark_type_t *bt,
-        vis_line_t top);
+                    bookmark_type_t *bt,
+                    vis_line_t top);
+void previous_cluster(bookmark_type_t *bt, textview_curses *tc);
+vis_line_t search_forward_from(textview_curses *tc);
 
 #endif

src/textview_curses.hh

@@ -638,7 +638,9 @@ public:
                     if (first_hit > 0) {
                         --first_hit;
                     }
-                    this->set_top(first_hit);
+                    if (first_hit > this->get_top()) {
+                        this->set_top(first_hit);
+                    }
                 }
             }
         }