# Mu - 100trace_browser.cc

      1 //: A debugging helper that lets you zoom in/out on a trace.
      2 //: Warning: this tool has zero automated tests.
      3 //:
      4 //: To try it out, first create an example trace:
      5 //:   mu --trace nqueens.mu
      6 //: Then to browse the trace, which was stored in a file called 'last_run':
      7 //:   mu browse-trace last_run
      8 //:
      9 //: You should now find yourself in a UI showing a subsequence of lines from
     10 //: the trace, each line starting with a numeric depth, and ending with a
     11 //: parenthetical count of trace lines hidden after it with greater depths.
     12 //:
     13 //: For example, this line:
     14 //:   2 app: line1 (30)
     15 //: indicates that it was logged with depth 2, and that 30 following lines
     16 //: have been hidden at a depth greater than 2.
     17 //:
     18 //: As an experiment, hidden counts of 1000 or more are in red to highlight
     19 //: where you might be particularly interested in expanding.
     20 //:
     21 //: The UI provides the following hotkeys:
     22 //:
     23 //:   `q` or `ctrl-c`: Quit.
     24 //:
     25 //:   `Enter`: 'Zoom into' this line. Expand some or all of the hidden lines
     26 //:   at the next higher level, updating parenthetical counts of hidden lines.
     27 //:
     28 //:   `Backspace`: 'Zoom out' on a line after zooming in, collapsing expanded
     29 //:   lines below by some series of <Enter> commands.
     30 //:
     31 //:   `j` or `down-arrow`: Move/scroll cursor down one line.
     32 //:   `k` or `up-arrow`: Move/scroll cursor up one line.
     33 //:   `J` or `ctrl-f` or `page-down`: Scroll cursor down one page.
     34 //:   `K` or `ctrl-b` or `page-up`: Scroll cursor up one page.
     35 //:   `h` or `left-arrow`: Scroll cursor left one character.
     36 //:   `l` or `right-arrow`: Scroll cursor right one character.
     37 //:   `H`: Scroll cursor left one screen-width.
     38 //:   `L`: Scroll cursor right one screen-width.
     39 //:
     40 //:   `g` or `home`: Move cursor to start of trace.
     41 //:   `G` or `end`: Move cursor to end of trace.
     42 //:
     43 //:   `t`: Move cursor to top line on screen.
     44 //:   `c`: Move cursor to center line on screen.
     45 //:   `b`: Move cursor to bottom line on screen.
     46 //:   `T`: Scroll line at cursor to top of screen.
     47 //:
     48 //:   `/`: Search forward for a pattern.
     49 //:   '?': Search backward for a pattern.
     50 //:   `n`: Repeat the previous '/' or '?'.
     51 //:   `N`: Repeat the previous '/' or '?' in the opposite direction.
     52 //:
     53 //:   After hitting `/`, a small editor on the bottom-most line supports the
     54 //:   following hotkeys:
     55 //:     ascii characters: add the key to the pattern.
     56 //:     `Enter`: search for the pattern.
     57 //:     `Esc` or `ctrl-c`: cancel the current search, setting the screen back
     58 //:       to its state before the search.
     59 //:     `left-arrow`: move cursor left.
     60 //:     `right-arrow`: move cursor right.
     61 //:     `ctrl-a` or `home`: move cursor to start of search pattern.
     62 //:     `ctrl-e` or `end`: move cursor to end of search pattern.
     63 //:     `ctrl-u`: clear search pattern before cursor
     64 //:     `ctrl-k`: clear search pattern at and after cursor
     65
     66 :(before "End Primitive Recipe Declarations")
     67 _BROWSE_TRACE,
     68 :(before "End Primitive Recipe Numbers")
     69 put(Recipe_ordinal, "$browse-trace", _BROWSE_TRACE);
     70 :(before "End Primitive Recipe Checks")
     71 case _BROWSE_TRACE: {
     72   break;
     73 }
     74 :(before "End Primitive Recipe Implementations")
     75 case _BROWSE_TRACE: {
     76   start_trace_browser();
     77   break;
     78 }
     79
     80 //: browse a trace loaded from a file
     81 :(after "Commandline Parsing")
     82 if (argc == 3 && is_equal(argv[1], "browse-trace")) {
     83   load_trace(argv[2]);
     84   start_trace_browser();
     85   return 0;
     86 }
     87
     88 :(before "End Globals")
     89 set<int> Visible;
     90 int Top_of_screen = 0;
     91 int Left_of_screen = 0;
     92 int Last_printed_row = 0;
     93 map<int, int> Trace_index;  // screen row -> trace index
     94 string Current_search_pattern = "";
     95 :(before "End Types")
     96 enum search_direction { FORWARD, BACKWARD };
     97 :(before "End Globals")
     98 search_direction Current_search_direction = FORWARD;
     99
    100 :(code)
    101 void start_trace_browser() {
    102   if (!Trace_stream) return;
    103   cerr << "computing min depth to display\n";
    104   int min_depth = 9999;
    105   for (int i = 0;  i < SIZE(Trace_stream->past_lines);  ++i) {
    106     trace_line& curr_line = Trace_stream->past_lines.at(i);
    107     if (curr_line.depth < min_depth) min_depth = curr_line.depth;
    108   }
    109   cerr << "min depth is " << min_depth << '\n';
    110   cerr << "computing lines to display\n";
    111   for (int i = 0;  i < SIZE(Trace_stream->past_lines);  ++i) {
    112     if (Trace_stream->past_lines.at(i).depth == min_depth)
    113       Visible.insert(i);
    114   }
    115   tb_init();
    116   tb_clear();
    117   Display_row = Display_column = 0;
    118   Top_of_screen = 0;
    119   refresh_screen_rows();
    120   while (true) {
    121     render();
    122     int key = read_key();
    123     if (key == 'q' || key == 'Q' || key == TB_KEY_CTRL_C) break;
    124     if (key == 'j' || key == TB_KEY_ARROW_DOWN) {
    125       // move cursor one line down
    126       if (Display_row < Last_printed_row) ++Display_row;
    127     }
    128     else if (key == 'k' || key == TB_KEY_ARROW_UP) {
    129       // move cursor one line up
    130       if (Display_row > 0) --Display_row;
    131     }
    132     else if (key == 't') {
    133       // move cursor to top of screen
    134       Display_row = 0;
    135     }
    136     else if (key == 'c') {
    137       // move cursor to center of screen
    138       Display_row = tb_height()/2;
    139       while (!contains_key(Trace_index, Display_row))
    140         --Display_row;
    141     }
    142     else if (key == 'b') {
    143       // move cursor to bottom of screen
    144       Display_row = tb_height()-1;
    145       while (!contains_key(Trace_index, Display_row))
    146         --Display_row;
    147     }
    148     else if (key == 'T') {
    149       // scroll line at cursor to top of screen
    150       Top_of_screen = get(Trace_index, Display_row);
    151       Display_row = 0;
    152       refresh_screen_rows();
    153     }
    154     else if (key == 'h' || key == TB_KEY_ARROW_LEFT) {
    155       // pan screen one character left
    156       if (Left_of_screen > 0) --Left_of_screen;
    157     }
    158     else if (key == 'l' || key == TB_KEY_ARROW_RIGHT) {
    159       // pan screen one character right
    160       ++Left_of_screen;
    161     }
    162     else if (key == 'H') {
    163       // pan screen one screen-width left
    164       Left_of_screen -= (tb_width() - 5);
    165       if (Left_of_screen < 0) Left_of_screen = 0;
    166     }
    167     else if (key == 'L') {
    168       // pan screen one screen-width right
    169       Left_of_screen += (tb_width() - 5);
    170     }
    171     else if (key == 'J' || key == TB_KEY_PGDN || key == TB_KEY_CTRL_F) {
    172       // page-down
    173       if (Trace_index.find(tb_height()-1) != Trace_index.end()) {
    174         Top_of_screen = get(Trace_index, tb_height()-1) + 1;
    175         refresh_screen_rows();
    176       }
    177     }
    178     else if (key == 'K' || key == TB_KEY_PGUP || key == TB_KEY_CTRL_B) {
    179       // page-up is more convoluted
    180       for (int screen_row = tb_height();  screen_row > 0 && Top_of_screen > 0;  --screen_row) {
    181         --Top_of_screen;
    182         if (Top_of_screen <= 0) break;
    183         while (Top_of_screen > 0 && !contains_key(Visible, Top_of_screen))
    184           --Top_of_screen;
    185       }
    186       if (Top_of_screen >= 0)
    187         refresh_screen_rows();
    188     }
    189     else if (key == 'g' || key == TB_KEY_HOME) {
    190         Top_of_screen = 0;
    191         Last_printed_row = 0;
    192         Display_row = 0;
    193         refresh_screen_rows();
    194     }
    195     else if (key == 'G' || key == TB_KEY_END) {
    196       // go to bottom of screen; largely like page-up, interestingly
    197       Top_of_screen = SIZE(Trace_stream->past_lines)-1;
    198       for (int screen_row = tb_height();  screen_row > 0 && Top_of_screen > 0;  --screen_row) {
    199         --Top_of_screen;
    200         if (Top_of_screen <= 0) break;
    201         while (Top_of_screen > 0 && !contains_key(Visible, Top_of_screen))
    202           --Top_of_screen;
    203       }
    204       refresh_screen_rows();
    205       // move cursor to bottom
    206       Display_row = Last_printed_row;
    207       refresh_screen_rows();
    208     }
    209     else if (key == TB_KEY_CARRIAGE_RETURN) {
    210       // expand lines under current by one level
    211       assert(contains_key(Trace_index, Display_row));
    212       int start_index = get(Trace_index, Display_row);
    213       int index = 0;
    214       // simultaneously compute end_index and min_depth
    215       int min_depth = 9999;
    216       for (index = start_index+1;  index < SIZE(Trace_stream->past_lines);  ++index) {
    217         if (contains_key(Visible, index)) break;
    218         trace_line& curr_line = Trace_stream->past_lines.at(index);
    219         assert(curr_line.depth > Trace_stream->past_lines.at(start_index).depth);
    220         if (curr_line.depth < min_depth) min_depth = curr_line.depth;
    221       }
    222       int end_index = index;
    223       // mark as visible all intervening indices at min_depth
    224       for (index = start_index;  index < end_index;  ++index) {
    225         trace_line& curr_line = Trace_stream->past_lines.at(index);
    226         if (curr_line.depth == min_depth) {
    227           Visible.insert(index);
    228         }
    229       }
    230       refresh_screen_rows();
    231     }
    232     else if (key == TB_KEY_BACKSPACE || key == TB_KEY_BACKSPACE2) {
    233       // collapse all lines under current
    234       assert(contains_key(Trace_index, Display_row));
    235       int start_index = get(Trace_index, Display_row);
    236       int index = 0;
    237       // end_index is the next line at a depth same as or lower than start_index
    238       int initial_depth = Trace_stream->past_lines.at(start_index).depth;
    239       for (index = start_index+1;  index < SIZE(Trace_stream->past_lines);  ++index) {
    240         if (!contains_key(Visible, index)) continue;
    241         trace_line& curr_line = Trace_stream->past_lines.at(index);
    242         if (curr_line.depth <= initial_depth) break;
    243       }
    244       int end_index = index;
    245       // mark as visible all intervening indices at min_depth
    246       for (index = start_index+1;  index < end_index;  ++index) {
    247         Visible.erase(index);
    248       }
    249       refresh_screen_rows();
    250     }
    251     else if (key == '/') {
    252       if (start_search_editor(FORWARD))
    253         search(Current_search_pattern, Current_search_direction);
    254     }
    255     else if (key == '?') {
    256       if (start_search_editor(BACKWARD))
    257         search(Current_search_pattern, Current_search_direction);
    258     }
    259     else if (key == 'n') {
    260       if (!Current_search_pattern.empty())
    261         search(Current_search_pattern, Current_search_direction);
    262     }
    263     else if (key == 'N') {
    264       if (!Current_search_pattern.empty())
    265         search(Current_search_pattern, opposite(Current_search_direction));
    266     }
    267   }
    268   tb_shutdown();
    269 }
    270
    271 bool start_search_editor(search_direction dir) {
    272   const int bottom_screen_line = tb_height()-1;
    273   // run a little editor just in the last line of the screen
    274   clear_line(bottom_screen_line);
    275   int col = 0;  // screen column of cursor on bottom line. also used to update pattern.
    276   tb_set_cursor(col, bottom_screen_line);
    277   tb_print('/', TB_WHITE, TB_BLACK);
    278   ++col;
    279   string pattern;
    280   while (true) {
    281     int key = read_key();
    282     if (key == TB_KEY_ENTER) {
    283       if (!pattern.empty()) {
    284         Current_search_pattern = pattern;
    285         Current_search_direction = dir;
    286       }
    287       return true;
    288     }
    289     else if (key == TB_KEY_ESC || key == TB_KEY_CTRL_C) {
    290       return false;
    291     }
    292     else if (key == TB_KEY_ARROW_LEFT) {
    293       if (col > /*slash*/1) {
    294         --col;
    295         tb_set_cursor(col, bottom_screen_line);
    296       }
    297     }
    298     else if (key == TB_KEY_ARROW_RIGHT) {
    299       if (col-/*slash*/1 < SIZE(pattern)) {
    300         ++col;
    301         tb_set_cursor(col, bottom_screen_line);
    302       }
    303     }
    304     else if (key == TB_KEY_HOME || key == TB_KEY_CTRL_A) {
    305       col = /*skip slash*/1;
    306       tb_set_cursor(col, bottom_screen_line);
    307     }
    308     else if (key == TB_KEY_END || key == TB_KEY_CTRL_E) {
    309       col = SIZE(pattern)+/*skip slash*/1;
    310       tb_set_cursor(col, bottom_screen_line);
    311     }
    312     else if (key == TB_KEY_BACKSPACE || key == TB_KEY_BACKSPACE2) {
    313       if (col > /*slash*/1) {
    314         assert(col <= SIZE(pattern)+1);
    315         --col;
    316         // update pattern
    317         pattern.erase(col-/*slash*/1, /*len*/1);
    318         // update screen
    319         tb_set_cursor(col, bottom_screen_line);
    320         for (int x = col;  x < SIZE(pattern)+/*skip slash*/1;  ++x)
    321           tb_print(pattern.at(x-/*slash*/1), TB_WHITE, TB_BLACK);
    322         tb_print(' ', TB_WHITE, TB_BLACK);
    323         tb_set_cursor(col, bottom_screen_line);
    324       }
    325     }
    326     else if (key == TB_KEY_CTRL_K) {
    327       int old_pattern_size = SIZE(pattern);
    328       pattern.erase(col-/*slash*/1, SIZE(pattern) - (col-/*slash*/1));
    329       tb_set_cursor(col, bottom_screen_line);
    330       for (int x = col;  x < old_pattern_size+/*slash*/1;  ++x)
    331         tb_print(' ', TB_WHITE, TB_BLACK);
    332       tb_set_cursor(col, bottom_screen_line);
    333     }
    334     else if (key == TB_KEY_CTRL_U) {
    335       int old_pattern_size = SIZE(pattern);
    336       pattern.erase(0, col-/*slash*/1);
    337       col = /*skip slash*/1;
    338       tb_set_cursor(col, bottom_screen_line);
    339       for (int x = /*slash*/1;  x < SIZE(pattern)+/*skip slash*/1;  ++x)
    340         tb_print(pattern.at(x-/*slash*/1), TB_WHITE, TB_BLACK);
    341       for (int x = SIZE(pattern)+/*slash*/1;  x < old_pattern_size+/*skip slash*/1;  ++x)
    342         tb_print(' ', TB_WHITE, TB_BLACK);
    343       tb_set_cursor(col, bottom_screen_line);
    344     }
    345     else if (key < 128) {  // ascii only
    346       // update pattern
    347       char c = static_cast<char>(key);
    348       assert(col-1 >= 0);
    349       assert(col-1 <= SIZE(pattern));
    350       pattern.insert(col-/*slash*/1, /*num*/1, c);
    351       // update screen
    352       for (int x = col;  x < SIZE(pattern)+/*skip slash*/1;  ++x)
    353         tb_print(pattern.at(x-/*slash*/1), TB_WHITE, TB_BLACK);
    354       ++col;
    355       tb_set_cursor(col, bottom_screen_line);
    356     }
    357   }
    358 }
    359
    360 void search(const string& pat, search_direction dir) {
    361   if (dir == FORWARD) search_next(pat);
    362   else search_previous(pat);
    363 }
    364
    365 search_direction opposite(search_direction dir) {
    366   if (dir == FORWARD) return BACKWARD;
    367   else return FORWARD;
    368 }
    369
    370 void search_next(const string& pat) {
    371   for (int trace_index = get(Trace_index, Display_row)+1;  trace_index < SIZE(Trace_stream->past_lines);  ++trace_index) {
    372     if (!contains_key(Visible, trace_index)) continue;
    373     const trace_line& line = Trace_stream->past_lines.at(trace_index);
    374     if (line.label.find(pat) == string::npos && line.contents.find(pat) == string::npos) continue;
    375     Top_of_screen = trace_index;
    376     Display_row = 0;
    377     refresh_screen_rows();
    378     return;
    379   }
    380 }
    381
    382 void search_previous(const string& pat) {
    383   for (int trace_index = get(Trace_index, Display_row)-1;  trace_index >= 0;  --trace_index) {
    384     if (!contains_key(Visible, trace_index)) continue;
    385     const trace_line& line = Trace_stream->past_lines.at(trace_index);
    386     if (line.label.find(pat) == string::npos && line.contents.find(pat) == string::npos) continue;
    387     Top_of_screen = trace_index;
    388     Display_row = 0;
    389     refresh_screen_rows();
    390     return;
    391   }
    392 }
    393
    394 void clear_line(int screen_row) {
    395   tb_set_cursor(0, screen_row);
    396   for (int col = 0;  col < tb_width();  ++col)
    397     tb_print(' ', TB_WHITE, TB_BLACK);
    398   tb_set_cursor(0, screen_row);
    399 }
    400
    401 // update Trace_indices for each screen_row on the basis of Top_of_screen and Visible
    402 void refresh_screen_rows() {
    403   int screen_row = 0, index = 0;
    404   Trace_index.clear();
    405   for (screen_row = 0, index = Top_of_screen;  screen_row < tb_height() && index < SIZE(Trace_stream->past_lines);  ++screen_row, ++index) {
    406     // skip lines without depth for now
    407     while (!contains_key(Visible, index)) {
    408       ++index;
    409       if (index >= SIZE(Trace_stream->past_lines)) goto done;
    410     }
    411     assert(index < SIZE(Trace_stream->past_lines));
    412     put(Trace_index, screen_row, index);
    413   }
    414 done:;
    415 }
    416
    417 void render() {
    418   int screen_row = 0;
    419   for (screen_row = 0;  screen_row < tb_height();  ++screen_row) {
    420     if (!contains_key(Trace_index, screen_row)) break;
    421     trace_line& curr_line = Trace_stream->past_lines.at(get(Trace_index, screen_row));
    422     ostringstream out;
    423     out << std::setw(4) << curr_line.depth << ' ' << curr_line.label << ": " << curr_line.contents;
    424     if (screen_row < tb_height()-1) {
    425       int delta = lines_hidden(screen_row);
    426       // home-brew escape sequence for red
    427       if (delta > 1) {
    428         if (delta > 999) out << static_cast<char>(1);
    429         out << " (" << delta << ")";
    430         if (delta > 999) out << static_cast<char>(2);
    431       }
    432     }
    433     render_line(screen_row, out.str(), screen_row == Display_row);
    434   }
    435   // clear rest of screen
    436   Last_printed_row = screen_row-1;
    437   for (;  screen_row < tb_height();  ++screen_row)
    438     render_line(screen_row, "~", /*cursor_line?*/false);
    439   // move cursor back to display row at the end
    440   tb_set_cursor(0, Display_row);
    441 }
    442
    443 int lines_hidden(int screen_row) {
    444   assert(contains_key(Trace_index, screen_row));
    445   if (!contains_key(Trace_index, screen_row+1))
    446     return SIZE(Trace_stream->past_lines) - get(Trace_index, screen_row);
    447   else
    448     return get(Trace_index, screen_row+1) - get(Trace_index, screen_row);
    449 }
    450
    451 void render_line(int screen_row, const string& s, bool cursor_line) {
    452   int col = 0;
    453   int color = TB_WHITE;
    454   int background_color = cursor_line ? /*subtle grey*/240 : TB_BLACK;
    455   vector<pair<size_t, size_t> > highlight_ranges = find_all_occurrences(s, Current_search_pattern);
    456   tb_set_cursor(0, screen_row);
    457   for (col = 0;  col < tb_width() && col+Left_of_screen < SIZE(s);  ++col) {
    458     char c = s.at(col+Left_of_screen);  // todo: unicode
    459     if (c == '\n') c = ';';  // replace newlines with semi-colons
    460     // escapes. hack: can't start a line with them.
    461     if (c == '\1') { color = /*red*/1;  c = ' '; }
    462     if (c == '\2') { color = TB_WHITE;  c = ' '; }
    463     if (in_range(highlight_ranges, col+Left_of_screen))
    464       tb_print(c, TB_BLACK, /*yellow*/11);
    465     else
    466       tb_print(c, color, background_color);
    467   }
    468   for (;  col < tb_width();  ++col)
    469     tb_print(' ', TB_WHITE, background_color);
    470 }
    471
    472 vector<pair<size_t, size_t> > find_all_occurrences(const string& s, const string& pat) {
    473   vector<pair<size_t, size_t> > result;
    474   if (pat.empty()) return result;
    475   size_t idx = 0;
    476   while (true) {
    477     size_t next_idx = s.find(pat, idx);
    478     if (next_idx == string::npos) break;
    479     result.push_back(pair<size_t, size_t>(next_idx, next_idx+SIZE(pat)));
    480     idx = next_idx+SIZE(pat);
    481   }
    482   return result;
    483 }
    484
    485 bool in_range(const vector<pair<size_t, size_t> >& highlight_ranges, size_t idx) {
    486   for (int i = 0;  i < SIZE(highlight_ranges);  ++i) {
    487     if (idx >= highlight_ranges.at(i).first && idx < highlight_ranges.at(i).second)
    488       return true;
    489     if (idx < highlight_ranges.at(i).second) break;
    490   }
    491   return false;
    492 }
    493
    494 void load_trace(const char* filename) {
    495   ifstream tin(filename);
    496   if (!tin) {
    497     cerr << "no such file: " << filename << '\n';
    498     exit(1);
    499   }
    500   Trace_stream = new trace_stream;
    501   while (has_data(tin)) {
    502     tin >> std::noskipws;
    503       skip_whitespace_but_not_newline(tin);
    504       if (!isdigit(tin.peek())) {
    505         string dummy;
    506         getline(tin, dummy);
    507         continue;
    508       }
    509     tin >> std::skipws;
    510     int depth;
    511     tin >> depth;
    512     string label;
    513     tin >> label;
    514     if (*--label.end() == ':') label.erase(--label.end());
    515     string line;
    516     getline(tin, line);
    517     Trace_stream->past_lines.push_back(trace_line(depth, label, line));
    518   }
    519   cerr << "lines read: " << Trace_stream->past_lines.size() << '\n';
    520 }
    521
    522 int read_key() {
    523   tb_event event;
    524   do {
    525     tb_poll_event(&event);
    526   } while (event.type != TB_EVENT_KEY);
    527   return event.key ? event.key : event.ch;
    528 }