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/scroll cursor down one line.
 31 //:   `k` or `up-arrow`: Move/scroll cursor up one line.
 32 //:   `J` or `ctrl-f` or `page-down`: Scroll cursor down one page.
 33 //:   `K` or `ctrl-b` or `page-up`: Scroll 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 //:   `t`: Move cursor to top line on screen.
 39 //:   `c`: Move cursor to center line on screen.
 40 //:   `b`: Move cursor to bottom line on screen.
 41 //:   `T`: Scroll line at cursor to top of screen.
 42 
 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 == 't') {
107   ¦ ¦ // move cursor to top of screen
108   ¦ ¦ Display_row = 0;
109   ¦ }
110   ¦ if (key == 'c') {
111   ¦ ¦ // move cursor to center of screen
112   ¦ ¦ Display_row = tb_height()/2;
113   ¦ }
114   ¦ if (key == 'b') {
115   ¦ ¦ // move cursor to bottom of screen
116   ¦ ¦ Display_row = tb_height()-1;
117   ¦ }
118   ¦ if (key == 'T') {
119   ¦ ¦ Top_of_screen = get(Trace_index, Display_row);
120   ¦ ¦ Display_row = 0;
121   ¦ ¦ refresh_screen_rows();
122   ¦ }
123   ¦ if (key == 'J' || key == TB_KEY_PGDN || key == TB_KEY_CTRL_F) {
124   ¦ ¦ // page-down
125   ¦ ¦ if (Trace_index.find(tb_height()-1) != Trace_index.end()) {
126   ¦ ¦ ¦ Top_of_screen = get(Trace_index, tb_height()-1) + 1;
127   ¦ ¦ ¦ refresh_screen_rows();
128   ¦ ¦ }
129   ¦ }
130   ¦ if (key == 'K' || key == TB_KEY_PGUP || key == TB_KEY_CTRL_B) {
131   ¦ ¦ // page-up is more convoluted
132   ¦ ¦ for (int screen_row = tb_height(); screen_row > 0 && Top_of_screen > 0; --screen_row) {
133   ¦ ¦ ¦ --Top_of_screen;
134   ¦ ¦ ¦ if (Top_of_screen <= 0) break;
135   ¦ ¦ ¦ while (Top_of_screen > 0 && !contains_key(Visible, Top_of_screen))
136   ¦ ¦ ¦ ¦ --Top_of_screen;
137   ¦ ¦ }
138   ¦ ¦ if (Top_of_screen >= 0)
139   ¦ ¦ ¦ refresh_screen_rows();
140   ¦ }
141   ¦ if (key == 'g' || key == TB_KEY_HOME) {
142   ¦ ¦ ¦ Top_of_screen = 0;
143   ¦ ¦ ¦ Last_printed_row = 0;
144   ¦ ¦ ¦ Display_row = 0;
145   ¦ ¦ ¦ refresh_screen_rows();
146   ¦ }
147   ¦ if (key == 'G' || key == TB_KEY_END) {
148   ¦ ¦ // go to bottom of screen; largely like page-up, interestingly
149   ¦ ¦ Top_of_screen = SIZE(Trace_stream->past_lines)-1;
150   ¦ ¦ for (int screen_row = tb_height(); screen_row > 0 && Top_of_screen > 0; --screen_row) {
151   ¦ ¦ ¦ --Top_of_screen;
152   ¦ ¦ ¦ if (Top_of_screen <= 0) break;
153   ¦ ¦ ¦ while (Top_of_screen > 0 && !contains_key(Visible, Top_of_screen))
154   ¦ ¦ ¦ ¦ --Top_of_screen;
155   ¦ ¦ }
156   ¦ ¦ refresh_screen_rows();
157   ¦ ¦ // move cursor to bottom
158   ¦ ¦ Display_row = Last_printed_row;
159   ¦ ¦ refresh_screen_rows();
160   ¦ }
161   ¦ if (key == TB_KEY_CARRIAGE_RETURN) {
162   ¦ ¦ // expand lines under current by one level
163   ¦ ¦ assert(contains_key(Trace_index, Display_row));
164   ¦ ¦ int start_index = get(Trace_index, Display_row);
165   ¦ ¦ int index = 0;
166   ¦ ¦ // simultaneously compute end_index and min_depth
167   ¦ ¦ int min_depth = 9999;
168   ¦ ¦ for (index = start_index+1; index < SIZE(Trace_stream->past_lines); ++index) {
169   ¦ ¦ ¦ if (contains_key(Visible, index)) break;
170   ¦ ¦ ¦ trace_line& curr_line = Trace_stream->past_lines.at(index);
171   ¦ ¦ ¦ assert(curr_line.depth > Trace_stream->past_lines.at(start_index).depth);
172   ¦ ¦ ¦ if (curr_line.depth < min_depth) min_depth = curr_line.depth;
173   ¦ ¦ }
174   ¦ ¦ int end_index = index;
175   ¦ ¦ // mark as visible all intervening indices at min_depth
176   ¦ ¦ for (index = start_index; index < end_index; ++index) {
177   ¦ ¦ ¦ trace_line& curr_line = Trace_stream->past_lines.at(index);
178   ¦ ¦ ¦ if (curr_line.depth == min_depth) {
179   ¦ ¦ ¦ ¦ Visible.insert(index);
180   ¦ ¦ ¦ }
181   ¦ ¦ }
182   ¦ ¦ refresh_screen_rows();
183   ¦ }
184   ¦ if (key == TB_KEY_BACKSPACE || key == TB_KEY_BACKSPACE2) {
185   ¦ ¦ // collapse all lines under current
186   ¦ ¦ assert(contains_key(Trace_index, Display_row));
187   ¦ ¦ int start_index = get(Trace_index, Display_row);
188   ¦ ¦ int index = 0;
189   ¦ ¦ // end_index is the next line at a depth same as or lower than start_index
190   ¦ ¦ int initial_depth = Trace_stream->past_lines.at(start_index).depth;
191   ¦ ¦ for (index = start_index+1; index < SIZE(Trace_stream->past_lines); ++index) {
192   ¦ ¦ ¦ if (!contains_key(Visible, index)) continue;
193   ¦ ¦ ¦ trace_line& curr_line = Trace_stream->past_lines.at(index);
194   ¦ ¦ ¦ if (curr_line.depth <= initial_depth) break;
195   ¦ ¦ }
196   ¦ ¦ int end_index = index;
197   ¦ ¦ // mark as visible all intervening indices at min_depth
198   ¦ ¦ for (index = start_index+1; index < end_index; ++index) {
199   ¦ ¦ ¦ Visible.erase(index);
200   ¦ ¦ }
201   ¦ ¦ refresh_screen_rows();
202   ¦ }
203   }
204   tb_shutdown();
205 }
206 
207 // update Trace_indices for each screen_row on the basis of Top_of_screen and Visible
208 void refresh_screen_rows() {
209   int screen_row = 0, index = 0;
210   Trace_index.clear();
211   for (screen_row = 0, index = Top_of_screen; screen_row < tb_height() && index < SIZE(Trace_stream->past_lines); ++screen_row, ++index) {
212   ¦ // skip lines without depth for now
213   ¦ while (!contains_key(Visible, index)) {
214   ¦ ¦ ++index;
215   ¦ ¦ if (index >= SIZE(Trace_stream->past_lines)) goto done;
216   ¦ }
217   ¦ assert(index < SIZE(Trace_stream->past_lines));
218   ¦ put(Trace_index, screen_row, index);
219   }
220 done:;
221 }
222 
223 void render() {
224   int screen_row = 0;
225   for (screen_row = 0; screen_row < tb_height(); ++screen_row) {
226   ¦ if (!contains_key(Trace_index, screen_row)) break;
227   ¦ trace_line& curr_line = Trace_stream->past_lines.at(get(Trace_index, screen_row));
228   ¦ ostringstream out;
229   ¦ out << std::setw(4) << curr_line.depth << ' ' << curr_line.label << ": " << curr_line.contents;
230   ¦ if (screen_row < tb_height()-1) {
231   ¦ ¦ int delta = lines_hidden(screen_row);
232   ¦ ¦ // home-brew escape sequence for red
233   ¦ ¦ if (delta > 999) out << static_cast<char>(1);
234   ¦ ¦ out << " (" << delta << ")";
235   ¦ ¦ if (delta > 999) out << static_cast<char>(2);
236   ¦ }
237   ¦ render_line(screen_row, out.str(), screen_row == Display_row);
238   }
239   // clear rest of screen
240   Last_printed_row = screen_row-1;
241   for (; screen_row < tb_height(); ++screen_row) {
242   ¦ render_line(screen_row, "~", /*highlight?*/false);
243   }
244   // move cursor back to display row at the end
245   tb_set_cursor(0, Display_row);
246   tb_present();
247 }
248 
249 int lines_hidden(int screen_row) {
250   assert(contains_key(Trace_index, screen_row));
251   if (!contains_key(Trace_index, screen_row+1))
252   ¦ return SIZE(Trace_stream->past_lines) - get(Trace_index, screen_row);
253   else
254   ¦ return get(Trace_index, screen_row+1) - get(Trace_index, screen_row);
255 }
256 
257 void render_line(int screen_row, const string& s, bool highlight) {
258   int col = 0;
259   int color = TB_WHITE;
260   for (col = 0; col < tb_width() && col < SIZE(s); ++col) {
261   ¦ char c = s.at(col);  // todo: unicode
262   ¦ if (c == '\n') c = ';';  // replace newlines with semi-colons
263   ¦ // escapes. hack: can't start a line with them.
264   ¦ if (c == '\1') { color = /*red*/1; c = ' '; }
265   ¦ if (c == '\2') { color = TB_WHITE; c = ' '; }
266   ¦ tb_change_cell(col, screen_row, c, color, highlight ? /*subtle grey*/240 : TB_BLACK);
267   }
268   for (; col < tb_width(); ++col)
269   ¦ tb_change_cell(col, screen_row, ' ', TB_WHITE, highlight ? /*subtle grey*/240 : TB_BLACK);
270 }
271 
272 void load_trace(const char* filename) {
273   ifstream tin(filename);
274   if (!tin) {
275   ¦ cerr << "no such file: " << filename << '\n';
276   ¦ exit(1);
277   }
278   Trace_stream = new trace_stream;
279   while (has_data(tin)) {
280   ¦ tin >> std::noskipws;
281   ¦ ¦ skip_whitespace_but_not_newline(tin);
282   ¦ ¦ if (!isdigit(tin.peek())) {
283   ¦ ¦ ¦ string dummy;
284   ¦ ¦ ¦ getline(tin, dummy);
285   ¦ ¦ ¦ continue;
286   ¦ ¦ }
287   ¦ tin >> std::skipws;
288   ¦ int depth;
289   ¦ tin >> depth;
290   ¦ string label;
291   ¦ tin >> label;
292   ¦ if (*--label.end() == ':') label.erase(--label.end());
293   ¦ string line;
294   ¦ getline(tin, line);
295   ¦ Trace_stream->past_lines.push_back(trace_line(depth, label, line));
296   }
297   cerr << "lines read: " << Trace_stream->past_lines.size() << '\n';
298 }