1 //: A debugging helper that lets you zoom in/out on a trace.
  2 //:
  3 //: To try it out, first create an example trace:
  4 //:   mu --trace nqueens.mu
  5 //: Then to browse the trace, which was stored in a file called 'last_run':
  6 //:   mu browse-trace last_run
  7 //:
  8 //: You should now find yourself in a UI showing a subsequence of lines from
  9 //: the trace, each line starting with a numeric depth, and ending with a
 10 //: parenthetical count of trace lines hidden after it with greater depths.
 11 //:
 12 //: For example, this line:
 13 //:   2 app: line1 (30)
 14 //: indicates that it was logged with depth 2, and that 30 following lines
 15 //: have been hidden at a depth greater than 2.
 16 //:
 17 //: As an experiment, hidden counts of 1000 or more are in red to highlight
 18 //: where you might be particularly interested in expanding.
 19 //:
 20 //: The UI provides the following hotkeys:
 21 //:
 22 //:   `q` or `ctrl-c`: Quit.
 23 //:
 24 //:   `Enter`: 'Zoom into' this line. Expand some or all of the hidden lines
 25 //:   at the next higher level, updating parenthetical counts of hidden lines.
 26 //:
 27 //:   `Backspace`: 'Zoom out' on a line after zooming in, collapsing expanded
 28 //:   lines below by some series of <Enter> commands.
 29 //:
 30 //:   `j` or `down-arrow`: Move cursor down one line.
 31 //:   `k` or `up-arrow`: Move cursor up one line.
 32 //:   `J` or `ctrl-f` or `page-down`: Move cursor down one page.
 33 //:   `K` or `ctrl-b` or `page-up`: Move cursor up one page.
 34 //:
 35 //:   `g` or `home`: Move cursor to start of trace.
 36 //:   `G` or `end`: Move cursor to end of trace.
 37 //:
 38 //:   `H`: Move cursor to top line on screen.
 39 //:   `M`: Move cursor to center line on screen.
 40 //:   `L`: Move cursor to bottom line on screen.
 41 
 42 //: browse the trace we just created
 43 :(before "End Primitive Recipe Declarations")
 44 _BROWSE_TRACE,
 45 :(before "End Primitive Recipe Numbers")
 46 put(Recipe_ordinal, "$browse-trace", _BROWSE_TRACE);
 47 :(before "End Primitive Recipe Checks")
 48 case _BROWSE_TRACE: {
 49   break;
 50 }
 51 :(before "End Primitive Recipe Implementations")
 52 case _BROWSE_TRACE: {
 53   start_trace_browser();
 54   break;
 55 }
 56 
 57 //: browse a trace loaded from a file
 58 :(after "Commandline Parsing")
 59 if (argc == 3 && is_equal(argv[1], "browse-trace")) {
 60   load_trace(argv[2]);
 61   start_trace_browser();
 62   return 0;
 63 }
 64 
 65 :(before "End Globals")
 66 set<int> Visible;
 67 int Top_of_screen = 0;
 68 int Last_printed_row = 0;
 69 map<int, int> Trace_index;  // screen row -> trace index
 70 
 71 :(code)
 72 void start_trace_browser() {
 73   if (!Trace_stream) return;
 74   cerr << "computing min depth to display\n";
 75   int min_depth = 9999;
 76   for (int i = 0; i < SIZE(Trace_stream->past_lines); ++i) {
 77     trace_line& curr_line = Trace_stream->past_lines.at(i);
 78     if (curr_line.depth < min_depth) min_depth = curr_line.depth;
 79   }
 80   cerr << "min depth is " << min_depth << '\n';
 81   cerr << "computing lines to display\n";
 82   for (int i = 0; i < SIZE(Trace_stream->past_lines); ++i) {
 83     if (Trace_stream->past_lines.at(i).depth == min_depth)
 84       Visible.insert(i);
 85   }
 86   tb_init();
 87   Display_row = Display_column = 0;
 88   tb_event event;
 89   Top_of_screen = 0;
 90   refresh_screen_rows();
 91   while (true) {
 92     render();
 93     do {
 94       tb_poll_event(&event);
 95     } while (event.type != TB_EVENT_KEY);
 96     int key = event.key ? event.key : event.ch;
 97     if (key == 'q' || key == 'Q' || key == TB_KEY_CTRL_C) break;
 98     if (key == 'j' || key == TB_KEY_ARROW_DOWN) {
 99       // move cursor one line down
100       if (Display_row < Last_printed_row) ++Display_row;
101     }
102     if (key == 'k' || key == TB_KEY_ARROW_UP) {
103       // move cursor one line up
104       if (Display_row > 0) --Display_row;
105     }
106     if (key == 'H') {
107       // move cursor to top of screen
108       Display_row = 0;
109     }
110     if (key == 'M') {
111       // move cursor to center of screen
112       Display_row = tb_height()/2;
113     }
114     if (key == 'L') {
115       // move cursor to bottom of screen
116       Display_row = tb_height()-1;
117     }
118     if (key == 'J' || key == TB_KEY_PGDN || key == TB_KEY_CTRL_F) {
119       // page-down
120       if (Trace_index.find(tb_height()-1) != Trace_index.end()) {
121         Top_of_screen = get(Trace_index, tb_height()-1) + 1;
122         refresh_screen_rows();
123       }
124     }
125     if (key == 'K' || key == TB_KEY_PGUP || key == TB_KEY_CTRL_B) {
126       // page-up is more convoluted
127       for (int screen_row = tb_height(); screen_row > 0 && Top_of_screen > 0; --screen_row) {
128         --Top_of_screen;
129         if (Top_of_screen <= 0) break;
130         while (Top_of_screen > 0 && !contains_key(Visible, Top_of_screen))
131           --Top_of_screen;
132       }
133       if (Top_of_screen >= 0)
134         refresh_screen_rows();
135     }
136     if (key == 'g' || key == TB_KEY_HOME) {
137         Top_of_screen = 0;
138         Last_printed_row = 0;
139         Display_row = 0;
140         refresh_screen_rows();
141     }
142     if (key == 'G' || key == TB_KEY_END) {
143       // go to bottom of screen; largely like page-up, interestingly
144       Top_of_screen = SIZE(Trace_stream->past_lines)-1;
145       for (int screen_row = tb_height(); screen_row > 0 && Top_of_screen > 0; --screen_row) {
146         --Top_of_screen;
147         if (Top_of_screen <= 0) break;
148         while (Top_of_screen > 0 && !contains_key(Visible, Top_of_screen))
149           --Top_of_screen;
150       }
151       refresh_screen_rows();
152       // move cursor to bottom
153       Display_row = Last_printed_row;
154       refresh_screen_rows();
155     }
156     if (key == TB_KEY_CARRIAGE_RETURN) {
157       // expand lines under current by one level
158       assert(contains_key(Trace_index, Display_row));
159       int start_index = get(Trace_index, Display_row);
160       int index = 0;
161       // simultaneously compute end_index and min_depth
162       int min_depth = 9999;
163       for (index = start_index+1; index < SIZE(Trace_stream->past_lines); ++index) {
164         if (contains_key(Visible, index)) break;
165         trace_line& curr_line = Trace_stream->past_lines.at(index);
166         assert(curr_line.depth > Trace_stream->past_lines.at(start_index).depth);
167         if (curr_line.depth < min_depth) min_depth = curr_line.depth;
168       }
169       int end_index = index;
170       // mark as visible all intervening indices at min_depth
171       for (index = start_index; index < end_index; ++index) {
172         trace_line& curr_line = Trace_stream->past_lines.at(index);
173         if (curr_line.depth == min_depth) {
174           Visible.insert(index);
175         }
176       }
177       refresh_screen_rows();
178     }
179     if (key == TB_KEY_BACKSPACE || key == TB_KEY_BACKSPACE2) {
180       // collapse all lines under current
181       assert(contains_key(Trace_index, Display_row));
182       int start_index = get(Trace_index, Display_row);
183       int index = 0;
184       // end_index is the next line at a depth same as or lower than start_index
185       int initial_depth = Trace_stream->past_lines.at(start_index).depth;
186       for (index = start_index+1; index < SIZE(Trace_stream->past_lines); ++index) {
187         if (!contains_key(Visible, index)) continue;
188         trace_line& curr_line = Trace_stream->past_lines.at(index);
189         if (curr_line.depth <= initial_depth) break;
190       }
191       int end_index = index;
192       // mark as visible all intervening indices at min_depth
193       for (index = start_index+1; index < end_index; ++index) {
194         Visible.erase(index);
195       }
196       refresh_screen_rows();
197     }
198   }
199   tb_shutdown();
200 }
201 
202 // update Trace_indices for each screen_row on the basis of Top_of_screen and Visible
203 void refresh_screen_rows() {
204   int screen_row = 0, index = 0;
205   Trace_index.clear();
206   for (screen_row = 0, index = Top_of_screen; screen_row < tb_height() && index < SIZE(Trace_stream->past_lines); ++screen_row, ++index) {
207     // skip lines without depth for now
208     while (!contains_key(Visible, index)) {
209       ++index;
210       if (index >= SIZE(Trace_stream->past_lines)) goto done;
211     }
212     assert(index < SIZE(Trace_stream->past_lines));
213     put(Trace_index, screen_row, index);
214   }
215 done:;
216 }
217 
218 void render() {
219   int screen_row = 0;
220   for (screen_row = 0; screen_row < tb_height(); ++screen_row) {
221     if (!contains_key(Trace_index, screen_row)) break;
222     trace_line& curr_line = Trace_stream->past_lines.at(get(Trace_index, screen_row));
223     ostringstream out;
224     out << std::setw(4) << curr_line.depth << ' ' << curr_line.label << ": " << curr_line.contents;
225     if (screen_row < tb_height()-1) {
226       int delta = lines_hidden(screen_row);
227       // home-brew escape sequence for red
228       if (delta > 999) out << static_cast<char>(1);
229       out << " (" << delta << ")";
230       if (delta > 999) out << static_cast<char>(2);
231     }
232     render_line(screen_row, out.str(), screen_row == Display_row);
233   }
234   // clear rest of screen
235   Last_printed_row = screen_row-1;
236   for (; screen_row < tb_height(); ++screen_row) {
237     render_line(screen_row, "~", /*highlight?*/false);
238   }
239   // move cursor back to display row at the end
240   tb_set_cursor(0, Display_row);
241   tb_present();
242 }
243 
244 int lines_hidden(int screen_row) {
245   assert(contains_key(Trace_index, screen_row));
246   if (!contains_key(Trace_index, screen_row+1))
247     return SIZE(Trace_stream->past_lines) - get(Trace_index, screen_row);
248   else
249     return get(Trace_index, screen_row+1) - get(Trace_index, screen_row);
250 }
251 
252 void render_line(int screen_row, const string& s, bool highlight) {
253   int col = 0;
254   int color = TB_WHITE;
255   for (col = 0; col < tb_width() && col < SIZE(s); ++col) {
256     char c = s.at(col);  // todo: unicode
257     if (c == '\n') c = ';';  // replace newlines with semi-colons
258     // escapes. hack: can't start a line with them.
259     if (c == '\1') { color = /*red*/1; c = ' '; }
260     if (c == '\2') { color = TB_WHITE; c = ' '; }
261     tb_change_cell(col, screen_row, c, color, highlight ? /*subtle grey*/240 : TB_BLACK);
262   }
263   for (; col < tb_width(); ++col)
264     tb_change_cell(col, screen_row, ' ', TB_WHITE, highlight ? /*subtle grey*/240 : TB_BLACK);
265 }
266 
267 void load_trace(const char* filename) {
268   ifstream tin(filename);
269   if (!tin) {
270     cerr << "no such file: " << filename << '\n';
271     exit(1);
272   }
273   Trace_stream = new trace_stream;
274   while (has_data(tin)) {
275     tin >> std::noskipws;
276       skip_whitespace_but_not_newline(tin);
277       if (!isdigit(tin.peek())) {
278         string dummy;
279         getline(tin, dummy);
280         continue;
281       }
282     tin >> std::skipws;
283     int depth;
284     tin >> depth;
285     string label;
286     tin >> label;
287     if (*--label.end() == ':') label.erase(--label.end());
288     string line;
289     getline(tin, line);
290     Trace_stream->past_lines.push_back(trace_line(depth, label, line));
291   }
292   cerr << "lines read: " << Trace_stream->past_lines.size() << '\n';
293 }