convert trivial cases to ALLOC_ARRAY
[git/git.git] / graph.c
1 #include "cache.h"
2 #include "commit.h"
3 #include "color.h"
4 #include "graph.h"
5 #include "diff.h"
6 #include "revision.h"
7
8 /* Internal API */
9
10 /*
11 * Output a padding line in the graph.
12 * This is similar to graph_next_line(). However, it is guaranteed to
13 * never print the current commit line. Instead, if the commit line is
14 * next, it will simply output a line of vertical padding, extending the
15 * branch lines downwards, but leaving them otherwise unchanged.
16 */
17 static void graph_padding_line(struct git_graph *graph, struct strbuf *sb);
18
19 /*
20 * Print a strbuf to stdout. If the graph is non-NULL, all lines but the
21 * first will be prefixed with the graph output.
22 *
23 * If the strbuf ends with a newline, the output will end after this
24 * newline. A new graph line will not be printed after the final newline.
25 * If the strbuf is empty, no output will be printed.
26 *
27 * Since the first line will not include the graph output, the caller is
28 * responsible for printing this line's graph (perhaps via
29 * graph_show_commit() or graph_show_oneline()) before calling
30 * graph_show_strbuf().
31 */
32 static void graph_show_strbuf(struct git_graph *graph, struct strbuf const *sb);
33
34 /*
35 * TODO:
36 * - Limit the number of columns, similar to the way gitk does.
37 * If we reach more than a specified number of columns, omit
38 * sections of some columns.
39 */
40
41 struct column {
42 /*
43 * The parent commit of this column.
44 */
45 struct commit *commit;
46 /*
47 * The color to (optionally) print this column in. This is an
48 * index into column_colors.
49 */
50 unsigned short color;
51 };
52
53 enum graph_state {
54 GRAPH_PADDING,
55 GRAPH_SKIP,
56 GRAPH_PRE_COMMIT,
57 GRAPH_COMMIT,
58 GRAPH_POST_MERGE,
59 GRAPH_COLLAPSING
60 };
61
62 static const char **column_colors;
63 static unsigned short column_colors_max;
64
65 void graph_set_column_colors(const char **colors, unsigned short colors_max)
66 {
67 column_colors = colors;
68 column_colors_max = colors_max;
69 }
70
71 static const char *column_get_color_code(unsigned short color)
72 {
73 return column_colors[color];
74 }
75
76 static void strbuf_write_column(struct strbuf *sb, const struct column *c,
77 char col_char)
78 {
79 if (c->color < column_colors_max)
80 strbuf_addstr(sb, column_get_color_code(c->color));
81 strbuf_addch(sb, col_char);
82 if (c->color < column_colors_max)
83 strbuf_addstr(sb, column_get_color_code(column_colors_max));
84 }
85
86 struct git_graph {
87 /*
88 * The commit currently being processed
89 */
90 struct commit *commit;
91 /* The rev-info used for the current traversal */
92 struct rev_info *revs;
93 /*
94 * The number of interesting parents that this commit has.
95 *
96 * Note that this is not the same as the actual number of parents.
97 * This count excludes parents that won't be printed in the graph
98 * output, as determined by graph_is_interesting().
99 */
100 int num_parents;
101 /*
102 * The width of the graph output for this commit.
103 * All rows for this commit are padded to this width, so that
104 * messages printed after the graph output are aligned.
105 */
106 int width;
107 /*
108 * The next expansion row to print
109 * when state is GRAPH_PRE_COMMIT
110 */
111 int expansion_row;
112 /*
113 * The current output state.
114 * This tells us what kind of line graph_next_line() should output.
115 */
116 enum graph_state state;
117 /*
118 * The output state for the previous line of output.
119 * This is primarily used to determine how the first merge line
120 * should appear, based on the last line of the previous commit.
121 */
122 enum graph_state prev_state;
123 /*
124 * The index of the column that refers to this commit.
125 *
126 * If none of the incoming columns refer to this commit,
127 * this will be equal to num_columns.
128 */
129 int commit_index;
130 /*
131 * The commit_index for the previously displayed commit.
132 *
133 * This is used to determine how the first line of a merge
134 * graph output should appear, based on the last line of the
135 * previous commit.
136 */
137 int prev_commit_index;
138 /*
139 * The maximum number of columns that can be stored in the columns
140 * and new_columns arrays. This is also half the number of entries
141 * that can be stored in the mapping and new_mapping arrays.
142 */
143 int column_capacity;
144 /*
145 * The number of columns (also called "branch lines" in some places)
146 */
147 int num_columns;
148 /*
149 * The number of columns in the new_columns array
150 */
151 int num_new_columns;
152 /*
153 * The number of entries in the mapping array
154 */
155 int mapping_size;
156 /*
157 * The column state before we output the current commit.
158 */
159 struct column *columns;
160 /*
161 * The new column state after we output the current commit.
162 * Only valid when state is GRAPH_COLLAPSING.
163 */
164 struct column *new_columns;
165 /*
166 * An array that tracks the current state of each
167 * character in the output line during state GRAPH_COLLAPSING.
168 * Each entry is -1 if this character is empty, or a non-negative
169 * integer if the character contains a branch line. The value of
170 * the integer indicates the target position for this branch line.
171 * (I.e., this array maps the current column positions to their
172 * desired positions.)
173 *
174 * The maximum capacity of this array is always
175 * sizeof(int) * 2 * column_capacity.
176 */
177 int *mapping;
178 /*
179 * A temporary array for computing the next mapping state
180 * while we are outputting a mapping line. This is stored as part
181 * of the git_graph simply so we don't have to allocate a new
182 * temporary array each time we have to output a collapsing line.
183 */
184 int *new_mapping;
185 /*
186 * The current default column color being used. This is
187 * stored as an index into the array column_colors.
188 */
189 unsigned short default_column_color;
190 };
191
192 static struct strbuf *diff_output_prefix_callback(struct diff_options *opt, void *data)
193 {
194 struct git_graph *graph = data;
195 static struct strbuf msgbuf = STRBUF_INIT;
196
197 assert(opt);
198 assert(graph);
199
200 opt->output_prefix_length = graph->width;
201 strbuf_reset(&msgbuf);
202 graph_padding_line(graph, &msgbuf);
203 return &msgbuf;
204 }
205
206 struct git_graph *graph_init(struct rev_info *opt)
207 {
208 struct git_graph *graph = xmalloc(sizeof(struct git_graph));
209
210 if (!column_colors)
211 graph_set_column_colors(column_colors_ansi,
212 column_colors_ansi_max);
213
214 graph->commit = NULL;
215 graph->revs = opt;
216 graph->num_parents = 0;
217 graph->expansion_row = 0;
218 graph->state = GRAPH_PADDING;
219 graph->prev_state = GRAPH_PADDING;
220 graph->commit_index = 0;
221 graph->prev_commit_index = 0;
222 graph->num_columns = 0;
223 graph->num_new_columns = 0;
224 graph->mapping_size = 0;
225 /*
226 * Start the column color at the maximum value, since we'll
227 * always increment it for the first commit we output.
228 * This way we start at 0 for the first commit.
229 */
230 graph->default_column_color = column_colors_max - 1;
231
232 /*
233 * Allocate a reasonably large default number of columns
234 * We'll automatically grow columns later if we need more room.
235 */
236 graph->column_capacity = 30;
237 ALLOC_ARRAY(graph->columns, graph->column_capacity);
238 ALLOC_ARRAY(graph->new_columns, graph->column_capacity);
239 ALLOC_ARRAY(graph->mapping, 2 * graph->column_capacity);
240 ALLOC_ARRAY(graph->new_mapping, 2 * graph->column_capacity);
241
242 /*
243 * The diff output prefix callback, with this we can make
244 * all the diff output to align with the graph lines.
245 */
246 opt->diffopt.output_prefix = diff_output_prefix_callback;
247 opt->diffopt.output_prefix_data = graph;
248 opt->diffopt.output_prefix_length = 0;
249
250 return graph;
251 }
252
253 static void graph_update_state(struct git_graph *graph, enum graph_state s)
254 {
255 graph->prev_state = graph->state;
256 graph->state = s;
257 }
258
259 static void graph_ensure_capacity(struct git_graph *graph, int num_columns)
260 {
261 if (graph->column_capacity >= num_columns)
262 return;
263
264 do {
265 graph->column_capacity *= 2;
266 } while (graph->column_capacity < num_columns);
267
268 REALLOC_ARRAY(graph->columns, graph->column_capacity);
269 REALLOC_ARRAY(graph->new_columns, graph->column_capacity);
270 REALLOC_ARRAY(graph->mapping, graph->column_capacity * 2);
271 REALLOC_ARRAY(graph->new_mapping, graph->column_capacity * 2);
272 }
273
274 /*
275 * Returns 1 if the commit will be printed in the graph output,
276 * and 0 otherwise.
277 */
278 static int graph_is_interesting(struct git_graph *graph, struct commit *commit)
279 {
280 /*
281 * If revs->boundary is set, commits whose children have
282 * been shown are always interesting, even if they have the
283 * UNINTERESTING or TREESAME flags set.
284 */
285 if (graph->revs && graph->revs->boundary) {
286 if (commit->object.flags & CHILD_SHOWN)
287 return 1;
288 }
289
290 /*
291 * Otherwise, use get_commit_action() to see if this commit is
292 * interesting
293 */
294 return get_commit_action(graph->revs, commit) == commit_show;
295 }
296
297 static struct commit_list *next_interesting_parent(struct git_graph *graph,
298 struct commit_list *orig)
299 {
300 struct commit_list *list;
301
302 /*
303 * If revs->first_parent_only is set, only the first
304 * parent is interesting. None of the others are.
305 */
306 if (graph->revs->first_parent_only)
307 return NULL;
308
309 /*
310 * Return the next interesting commit after orig
311 */
312 for (list = orig->next; list; list = list->next) {
313 if (graph_is_interesting(graph, list->item))
314 return list;
315 }
316
317 return NULL;
318 }
319
320 static struct commit_list *first_interesting_parent(struct git_graph *graph)
321 {
322 struct commit_list *parents = graph->commit->parents;
323
324 /*
325 * If this commit has no parents, ignore it
326 */
327 if (!parents)
328 return NULL;
329
330 /*
331 * If the first parent is interesting, return it
332 */
333 if (graph_is_interesting(graph, parents->item))
334 return parents;
335
336 /*
337 * Otherwise, call next_interesting_parent() to get
338 * the next interesting parent
339 */
340 return next_interesting_parent(graph, parents);
341 }
342
343 static unsigned short graph_get_current_column_color(const struct git_graph *graph)
344 {
345 if (!want_color(graph->revs->diffopt.use_color))
346 return column_colors_max;
347 return graph->default_column_color;
348 }
349
350 /*
351 * Update the graph's default column color.
352 */
353 static void graph_increment_column_color(struct git_graph *graph)
354 {
355 graph->default_column_color = (graph->default_column_color + 1) %
356 column_colors_max;
357 }
358
359 static unsigned short graph_find_commit_color(const struct git_graph *graph,
360 const struct commit *commit)
361 {
362 int i;
363 for (i = 0; i < graph->num_columns; i++) {
364 if (graph->columns[i].commit == commit)
365 return graph->columns[i].color;
366 }
367 return graph_get_current_column_color(graph);
368 }
369
370 static void graph_insert_into_new_columns(struct git_graph *graph,
371 struct commit *commit,
372 int *mapping_index)
373 {
374 int i;
375
376 /*
377 * If the commit is already in the new_columns list, we don't need to
378 * add it. Just update the mapping correctly.
379 */
380 for (i = 0; i < graph->num_new_columns; i++) {
381 if (graph->new_columns[i].commit == commit) {
382 graph->mapping[*mapping_index] = i;
383 *mapping_index += 2;
384 return;
385 }
386 }
387
388 /*
389 * This commit isn't already in new_columns. Add it.
390 */
391 graph->new_columns[graph->num_new_columns].commit = commit;
392 graph->new_columns[graph->num_new_columns].color = graph_find_commit_color(graph, commit);
393 graph->mapping[*mapping_index] = graph->num_new_columns;
394 *mapping_index += 2;
395 graph->num_new_columns++;
396 }
397
398 static void graph_update_width(struct git_graph *graph,
399 int is_commit_in_existing_columns)
400 {
401 /*
402 * Compute the width needed to display the graph for this commit.
403 * This is the maximum width needed for any row. All other rows
404 * will be padded to this width.
405 *
406 * Compute the number of columns in the widest row:
407 * Count each existing column (graph->num_columns), and each new
408 * column added by this commit.
409 */
410 int max_cols = graph->num_columns + graph->num_parents;
411
412 /*
413 * Even if the current commit has no parents to be printed, it
414 * still takes up a column for itself.
415 */
416 if (graph->num_parents < 1)
417 max_cols++;
418
419 /*
420 * We added a column for the current commit as part of
421 * graph->num_parents. If the current commit was already in
422 * graph->columns, then we have double counted it.
423 */
424 if (is_commit_in_existing_columns)
425 max_cols--;
426
427 /*
428 * Each column takes up 2 spaces
429 */
430 graph->width = max_cols * 2;
431 }
432
433 static void graph_update_columns(struct git_graph *graph)
434 {
435 struct commit_list *parent;
436 struct column *tmp_columns;
437 int max_new_columns;
438 int mapping_idx;
439 int i, seen_this, is_commit_in_columns;
440
441 /*
442 * Swap graph->columns with graph->new_columns
443 * graph->columns contains the state for the previous commit,
444 * and new_columns now contains the state for our commit.
445 *
446 * We'll re-use the old columns array as storage to compute the new
447 * columns list for the commit after this one.
448 */
449 tmp_columns = graph->columns;
450 graph->columns = graph->new_columns;
451 graph->num_columns = graph->num_new_columns;
452
453 graph->new_columns = tmp_columns;
454 graph->num_new_columns = 0;
455
456 /*
457 * Now update new_columns and mapping with the information for the
458 * commit after this one.
459 *
460 * First, make sure we have enough room. At most, there will
461 * be graph->num_columns + graph->num_parents columns for the next
462 * commit.
463 */
464 max_new_columns = graph->num_columns + graph->num_parents;
465 graph_ensure_capacity(graph, max_new_columns);
466
467 /*
468 * Clear out graph->mapping
469 */
470 graph->mapping_size = 2 * max_new_columns;
471 for (i = 0; i < graph->mapping_size; i++)
472 graph->mapping[i] = -1;
473
474 /*
475 * Populate graph->new_columns and graph->mapping
476 *
477 * Some of the parents of this commit may already be in
478 * graph->columns. If so, graph->new_columns should only contain a
479 * single entry for each such commit. graph->mapping should
480 * contain information about where each current branch line is
481 * supposed to end up after the collapsing is performed.
482 */
483 seen_this = 0;
484 mapping_idx = 0;
485 is_commit_in_columns = 1;
486 for (i = 0; i <= graph->num_columns; i++) {
487 struct commit *col_commit;
488 if (i == graph->num_columns) {
489 if (seen_this)
490 break;
491 is_commit_in_columns = 0;
492 col_commit = graph->commit;
493 } else {
494 col_commit = graph->columns[i].commit;
495 }
496
497 if (col_commit == graph->commit) {
498 int old_mapping_idx = mapping_idx;
499 seen_this = 1;
500 graph->commit_index = i;
501 for (parent = first_interesting_parent(graph);
502 parent;
503 parent = next_interesting_parent(graph, parent)) {
504 /*
505 * If this is a merge, or the start of a new
506 * childless column, increment the current
507 * color.
508 */
509 if (graph->num_parents > 1 ||
510 !is_commit_in_columns) {
511 graph_increment_column_color(graph);
512 }
513 graph_insert_into_new_columns(graph,
514 parent->item,
515 &mapping_idx);
516 }
517 /*
518 * We always need to increment mapping_idx by at
519 * least 2, even if it has no interesting parents.
520 * The current commit always takes up at least 2
521 * spaces.
522 */
523 if (mapping_idx == old_mapping_idx)
524 mapping_idx += 2;
525 } else {
526 graph_insert_into_new_columns(graph, col_commit,
527 &mapping_idx);
528 }
529 }
530
531 /*
532 * Shrink mapping_size to be the minimum necessary
533 */
534 while (graph->mapping_size > 1 &&
535 graph->mapping[graph->mapping_size - 1] < 0)
536 graph->mapping_size--;
537
538 /*
539 * Compute graph->width for this commit
540 */
541 graph_update_width(graph, is_commit_in_columns);
542 }
543
544 void graph_update(struct git_graph *graph, struct commit *commit)
545 {
546 struct commit_list *parent;
547
548 /*
549 * Set the new commit
550 */
551 graph->commit = commit;
552
553 /*
554 * Count how many interesting parents this commit has
555 */
556 graph->num_parents = 0;
557 for (parent = first_interesting_parent(graph);
558 parent;
559 parent = next_interesting_parent(graph, parent))
560 {
561 graph->num_parents++;
562 }
563
564 /*
565 * Store the old commit_index in prev_commit_index.
566 * graph_update_columns() will update graph->commit_index for this
567 * commit.
568 */
569 graph->prev_commit_index = graph->commit_index;
570
571 /*
572 * Call graph_update_columns() to update
573 * columns, new_columns, and mapping.
574 */
575 graph_update_columns(graph);
576
577 graph->expansion_row = 0;
578
579 /*
580 * Update graph->state.
581 * Note that we don't call graph_update_state() here, since
582 * we don't want to update graph->prev_state. No line for
583 * graph->state was ever printed.
584 *
585 * If the previous commit didn't get to the GRAPH_PADDING state,
586 * it never finished its output. Goto GRAPH_SKIP, to print out
587 * a line to indicate that portion of the graph is missing.
588 *
589 * If there are 3 or more parents, we may need to print extra rows
590 * before the commit, to expand the branch lines around it and make
591 * room for it. We need to do this only if there is a branch row
592 * (or more) to the right of this commit.
593 *
594 * If there are less than 3 parents, we can immediately print the
595 * commit line.
596 */
597 if (graph->state != GRAPH_PADDING)
598 graph->state = GRAPH_SKIP;
599 else if (graph->num_parents >= 3 &&
600 graph->commit_index < (graph->num_columns - 1))
601 graph->state = GRAPH_PRE_COMMIT;
602 else
603 graph->state = GRAPH_COMMIT;
604 }
605
606 static int graph_is_mapping_correct(struct git_graph *graph)
607 {
608 int i;
609
610 /*
611 * The mapping is up to date if each entry is at its target,
612 * or is 1 greater than its target.
613 * (If it is 1 greater than the target, '/' will be printed, so it
614 * will look correct on the next row.)
615 */
616 for (i = 0; i < graph->mapping_size; i++) {
617 int target = graph->mapping[i];
618 if (target < 0)
619 continue;
620 if (target == (i / 2))
621 continue;
622 return 0;
623 }
624
625 return 1;
626 }
627
628 static void graph_pad_horizontally(struct git_graph *graph, struct strbuf *sb,
629 int chars_written)
630 {
631 /*
632 * Add additional spaces to the end of the strbuf, so that all
633 * lines for a particular commit have the same width.
634 *
635 * This way, fields printed to the right of the graph will remain
636 * aligned for the entire commit.
637 */
638 int extra;
639 if (chars_written >= graph->width)
640 return;
641
642 extra = graph->width - chars_written;
643 strbuf_addf(sb, "%*s", (int) extra, "");
644 }
645
646 static void graph_output_padding_line(struct git_graph *graph,
647 struct strbuf *sb)
648 {
649 int i;
650
651 /*
652 * We could conceivable be called with a NULL commit
653 * if our caller has a bug, and invokes graph_next_line()
654 * immediately after graph_init(), without first calling
655 * graph_update(). Return without outputting anything in this
656 * case.
657 */
658 if (!graph->commit)
659 return;
660
661 /*
662 * Output a padding row, that leaves all branch lines unchanged
663 */
664 for (i = 0; i < graph->num_new_columns; i++) {
665 strbuf_write_column(sb, &graph->new_columns[i], '|');
666 strbuf_addch(sb, ' ');
667 }
668
669 graph_pad_horizontally(graph, sb, graph->num_new_columns * 2);
670 }
671
672 static void graph_output_skip_line(struct git_graph *graph, struct strbuf *sb)
673 {
674 /*
675 * Output an ellipsis to indicate that a portion
676 * of the graph is missing.
677 */
678 strbuf_addstr(sb, "...");
679 graph_pad_horizontally(graph, sb, 3);
680
681 if (graph->num_parents >= 3 &&
682 graph->commit_index < (graph->num_columns - 1))
683 graph_update_state(graph, GRAPH_PRE_COMMIT);
684 else
685 graph_update_state(graph, GRAPH_COMMIT);
686 }
687
688 static void graph_output_pre_commit_line(struct git_graph *graph,
689 struct strbuf *sb)
690 {
691 int num_expansion_rows;
692 int i, seen_this;
693 int chars_written;
694
695 /*
696 * This function formats a row that increases the space around a commit
697 * with multiple parents, to make room for it. It should only be
698 * called when there are 3 or more parents.
699 *
700 * We need 2 extra rows for every parent over 2.
701 */
702 assert(graph->num_parents >= 3);
703 num_expansion_rows = (graph->num_parents - 2) * 2;
704
705 /*
706 * graph->expansion_row tracks the current expansion row we are on.
707 * It should be in the range [0, num_expansion_rows - 1]
708 */
709 assert(0 <= graph->expansion_row &&
710 graph->expansion_row < num_expansion_rows);
711
712 /*
713 * Output the row
714 */
715 seen_this = 0;
716 chars_written = 0;
717 for (i = 0; i < graph->num_columns; i++) {
718 struct column *col = &graph->columns[i];
719 if (col->commit == graph->commit) {
720 seen_this = 1;
721 strbuf_write_column(sb, col, '|');
722 strbuf_addf(sb, "%*s", graph->expansion_row, "");
723 chars_written += 1 + graph->expansion_row;
724 } else if (seen_this && (graph->expansion_row == 0)) {
725 /*
726 * This is the first line of the pre-commit output.
727 * If the previous commit was a merge commit and
728 * ended in the GRAPH_POST_MERGE state, all branch
729 * lines after graph->prev_commit_index were
730 * printed as "\" on the previous line. Continue
731 * to print them as "\" on this line. Otherwise,
732 * print the branch lines as "|".
733 */
734 if (graph->prev_state == GRAPH_POST_MERGE &&
735 graph->prev_commit_index < i)
736 strbuf_write_column(sb, col, '\\');
737 else
738 strbuf_write_column(sb, col, '|');
739 chars_written++;
740 } else if (seen_this && (graph->expansion_row > 0)) {
741 strbuf_write_column(sb, col, '\\');
742 chars_written++;
743 } else {
744 strbuf_write_column(sb, col, '|');
745 chars_written++;
746 }
747 strbuf_addch(sb, ' ');
748 chars_written++;
749 }
750
751 graph_pad_horizontally(graph, sb, chars_written);
752
753 /*
754 * Increment graph->expansion_row,
755 * and move to state GRAPH_COMMIT if necessary
756 */
757 graph->expansion_row++;
758 if (graph->expansion_row >= num_expansion_rows)
759 graph_update_state(graph, GRAPH_COMMIT);
760 }
761
762 static void graph_output_commit_char(struct git_graph *graph, struct strbuf *sb)
763 {
764 /*
765 * For boundary commits, print 'o'
766 * (We should only see boundary commits when revs->boundary is set.)
767 */
768 if (graph->commit->object.flags & BOUNDARY) {
769 assert(graph->revs->boundary);
770 strbuf_addch(sb, 'o');
771 return;
772 }
773
774 /*
775 * get_revision_mark() handles all other cases without assert()
776 */
777 strbuf_addstr(sb, get_revision_mark(graph->revs, graph->commit));
778 }
779
780 /*
781 * Draw an octopus merge and return the number of characters written.
782 */
783 static int graph_draw_octopus_merge(struct git_graph *graph,
784 struct strbuf *sb)
785 {
786 /*
787 * Here dashless_commits represents the number of parents
788 * which don't need to have dashes (because their edges fit
789 * neatly under the commit).
790 */
791 const int dashless_commits = 2;
792 int col_num, i;
793 int num_dashes =
794 ((graph->num_parents - dashless_commits) * 2) - 1;
795 for (i = 0; i < num_dashes; i++) {
796 col_num = (i / 2) + dashless_commits + graph->commit_index;
797 strbuf_write_column(sb, &graph->new_columns[col_num], '-');
798 }
799 col_num = (i / 2) + dashless_commits + graph->commit_index;
800 strbuf_write_column(sb, &graph->new_columns[col_num], '.');
801 return num_dashes + 1;
802 }
803
804 static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
805 {
806 int seen_this = 0;
807 int i, chars_written;
808
809 /*
810 * Output the row containing this commit
811 * Iterate up to and including graph->num_columns,
812 * since the current commit may not be in any of the existing
813 * columns. (This happens when the current commit doesn't have any
814 * children that we have already processed.)
815 */
816 seen_this = 0;
817 chars_written = 0;
818 for (i = 0; i <= graph->num_columns; i++) {
819 struct column *col = &graph->columns[i];
820 struct commit *col_commit;
821 if (i == graph->num_columns) {
822 if (seen_this)
823 break;
824 col_commit = graph->commit;
825 } else {
826 col_commit = graph->columns[i].commit;
827 }
828
829 if (col_commit == graph->commit) {
830 seen_this = 1;
831 graph_output_commit_char(graph, sb);
832 chars_written++;
833
834 if (graph->num_parents > 2)
835 chars_written += graph_draw_octopus_merge(graph,
836 sb);
837 } else if (seen_this && (graph->num_parents > 2)) {
838 strbuf_write_column(sb, col, '\\');
839 chars_written++;
840 } else if (seen_this && (graph->num_parents == 2)) {
841 /*
842 * This is a 2-way merge commit.
843 * There is no GRAPH_PRE_COMMIT stage for 2-way
844 * merges, so this is the first line of output
845 * for this commit. Check to see what the previous
846 * line of output was.
847 *
848 * If it was GRAPH_POST_MERGE, the branch line
849 * coming into this commit may have been '\',
850 * and not '|' or '/'. If so, output the branch
851 * line as '\' on this line, instead of '|'. This
852 * makes the output look nicer.
853 */
854 if (graph->prev_state == GRAPH_POST_MERGE &&
855 graph->prev_commit_index < i)
856 strbuf_write_column(sb, col, '\\');
857 else
858 strbuf_write_column(sb, col, '|');
859 chars_written++;
860 } else {
861 strbuf_write_column(sb, col, '|');
862 chars_written++;
863 }
864 strbuf_addch(sb, ' ');
865 chars_written++;
866 }
867
868 graph_pad_horizontally(graph, sb, chars_written);
869
870 /*
871 * Update graph->state
872 */
873 if (graph->num_parents > 1)
874 graph_update_state(graph, GRAPH_POST_MERGE);
875 else if (graph_is_mapping_correct(graph))
876 graph_update_state(graph, GRAPH_PADDING);
877 else
878 graph_update_state(graph, GRAPH_COLLAPSING);
879 }
880
881 static struct column *find_new_column_by_commit(struct git_graph *graph,
882 struct commit *commit)
883 {
884 int i;
885 for (i = 0; i < graph->num_new_columns; i++) {
886 if (graph->new_columns[i].commit == commit)
887 return &graph->new_columns[i];
888 }
889 return NULL;
890 }
891
892 static void graph_output_post_merge_line(struct git_graph *graph, struct strbuf *sb)
893 {
894 int seen_this = 0;
895 int i, j, chars_written;
896
897 /*
898 * Output the post-merge row
899 */
900 chars_written = 0;
901 for (i = 0; i <= graph->num_columns; i++) {
902 struct column *col = &graph->columns[i];
903 struct commit *col_commit;
904 if (i == graph->num_columns) {
905 if (seen_this)
906 break;
907 col_commit = graph->commit;
908 } else {
909 col_commit = col->commit;
910 }
911
912 if (col_commit == graph->commit) {
913 /*
914 * Since the current commit is a merge find
915 * the columns for the parent commits in
916 * new_columns and use those to format the
917 * edges.
918 */
919 struct commit_list *parents = NULL;
920 struct column *par_column;
921 seen_this = 1;
922 parents = first_interesting_parent(graph);
923 assert(parents);
924 par_column = find_new_column_by_commit(graph, parents->item);
925 assert(par_column);
926
927 strbuf_write_column(sb, par_column, '|');
928 chars_written++;
929 for (j = 0; j < graph->num_parents - 1; j++) {
930 parents = next_interesting_parent(graph, parents);
931 assert(parents);
932 par_column = find_new_column_by_commit(graph, parents->item);
933 assert(par_column);
934 strbuf_write_column(sb, par_column, '\\');
935 strbuf_addch(sb, ' ');
936 }
937 chars_written += j * 2;
938 } else if (seen_this) {
939 strbuf_write_column(sb, col, '\\');
940 strbuf_addch(sb, ' ');
941 chars_written += 2;
942 } else {
943 strbuf_write_column(sb, col, '|');
944 strbuf_addch(sb, ' ');
945 chars_written += 2;
946 }
947 }
948
949 graph_pad_horizontally(graph, sb, chars_written);
950
951 /*
952 * Update graph->state
953 */
954 if (graph_is_mapping_correct(graph))
955 graph_update_state(graph, GRAPH_PADDING);
956 else
957 graph_update_state(graph, GRAPH_COLLAPSING);
958 }
959
960 static void graph_output_collapsing_line(struct git_graph *graph, struct strbuf *sb)
961 {
962 int i;
963 int *tmp_mapping;
964 short used_horizontal = 0;
965 int horizontal_edge = -1;
966 int horizontal_edge_target = -1;
967
968 /*
969 * Clear out the new_mapping array
970 */
971 for (i = 0; i < graph->mapping_size; i++)
972 graph->new_mapping[i] = -1;
973
974 for (i = 0; i < graph->mapping_size; i++) {
975 int target = graph->mapping[i];
976 if (target < 0)
977 continue;
978
979 /*
980 * Since update_columns() always inserts the leftmost
981 * column first, each branch's target location should
982 * always be either its current location or to the left of
983 * its current location.
984 *
985 * We never have to move branches to the right. This makes
986 * the graph much more legible, since whenever branches
987 * cross, only one is moving directions.
988 */
989 assert(target * 2 <= i);
990
991 if (target * 2 == i) {
992 /*
993 * This column is already in the
994 * correct place
995 */
996 assert(graph->new_mapping[i] == -1);
997 graph->new_mapping[i] = target;
998 } else if (graph->new_mapping[i - 1] < 0) {
999 /*
1000 * Nothing is to the left.
1001 * Move to the left by one
1002 */
1003 graph->new_mapping[i - 1] = target;
1004 /*
1005 * If there isn't already an edge moving horizontally
1006 * select this one.
1007 */
1008 if (horizontal_edge == -1) {
1009 int j;
1010 horizontal_edge = i;
1011 horizontal_edge_target = target;
1012 /*
1013 * The variable target is the index of the graph
1014 * column, and therefore target*2+3 is the
1015 * actual screen column of the first horizontal
1016 * line.
1017 */
1018 for (j = (target * 2)+3; j < (i - 2); j += 2)
1019 graph->new_mapping[j] = target;
1020 }
1021 } else if (graph->new_mapping[i - 1] == target) {
1022 /*
1023 * There is a branch line to our left
1024 * already, and it is our target. We
1025 * combine with this line, since we share
1026 * the same parent commit.
1027 *
1028 * We don't have to add anything to the
1029 * output or new_mapping, since the
1030 * existing branch line has already taken
1031 * care of it.
1032 */
1033 } else {
1034 /*
1035 * There is a branch line to our left,
1036 * but it isn't our target. We need to
1037 * cross over it.
1038 *
1039 * The space just to the left of this
1040 * branch should always be empty.
1041 *
1042 * The branch to the left of that space
1043 * should be our eventual target.
1044 */
1045 assert(graph->new_mapping[i - 1] > target);
1046 assert(graph->new_mapping[i - 2] < 0);
1047 assert(graph->new_mapping[i - 3] == target);
1048 graph->new_mapping[i - 2] = target;
1049 /*
1050 * Mark this branch as the horizontal edge to
1051 * prevent any other edges from moving
1052 * horizontally.
1053 */
1054 if (horizontal_edge == -1)
1055 horizontal_edge = i;
1056 }
1057 }
1058
1059 /*
1060 * The new mapping may be 1 smaller than the old mapping
1061 */
1062 if (graph->new_mapping[graph->mapping_size - 1] < 0)
1063 graph->mapping_size--;
1064
1065 /*
1066 * Output out a line based on the new mapping info
1067 */
1068 for (i = 0; i < graph->mapping_size; i++) {
1069 int target = graph->new_mapping[i];
1070 if (target < 0)
1071 strbuf_addch(sb, ' ');
1072 else if (target * 2 == i)
1073 strbuf_write_column(sb, &graph->new_columns[target], '|');
1074 else if (target == horizontal_edge_target &&
1075 i != horizontal_edge - 1) {
1076 /*
1077 * Set the mappings for all but the
1078 * first segment to -1 so that they
1079 * won't continue into the next line.
1080 */
1081 if (i != (target * 2)+3)
1082 graph->new_mapping[i] = -1;
1083 used_horizontal = 1;
1084 strbuf_write_column(sb, &graph->new_columns[target], '_');
1085 } else {
1086 if (used_horizontal && i < horizontal_edge)
1087 graph->new_mapping[i] = -1;
1088 strbuf_write_column(sb, &graph->new_columns[target], '/');
1089
1090 }
1091 }
1092
1093 graph_pad_horizontally(graph, sb, graph->mapping_size);
1094
1095 /*
1096 * Swap mapping and new_mapping
1097 */
1098 tmp_mapping = graph->mapping;
1099 graph->mapping = graph->new_mapping;
1100 graph->new_mapping = tmp_mapping;
1101
1102 /*
1103 * If graph->mapping indicates that all of the branch lines
1104 * are already in the correct positions, we are done.
1105 * Otherwise, we need to collapse some branch lines together.
1106 */
1107 if (graph_is_mapping_correct(graph))
1108 graph_update_state(graph, GRAPH_PADDING);
1109 }
1110
1111 int graph_next_line(struct git_graph *graph, struct strbuf *sb)
1112 {
1113 switch (graph->state) {
1114 case GRAPH_PADDING:
1115 graph_output_padding_line(graph, sb);
1116 return 0;
1117 case GRAPH_SKIP:
1118 graph_output_skip_line(graph, sb);
1119 return 0;
1120 case GRAPH_PRE_COMMIT:
1121 graph_output_pre_commit_line(graph, sb);
1122 return 0;
1123 case GRAPH_COMMIT:
1124 graph_output_commit_line(graph, sb);
1125 return 1;
1126 case GRAPH_POST_MERGE:
1127 graph_output_post_merge_line(graph, sb);
1128 return 0;
1129 case GRAPH_COLLAPSING:
1130 graph_output_collapsing_line(graph, sb);
1131 return 0;
1132 }
1133
1134 assert(0);
1135 return 0;
1136 }
1137
1138 static void graph_padding_line(struct git_graph *graph, struct strbuf *sb)
1139 {
1140 int i;
1141
1142 if (graph->state != GRAPH_COMMIT) {
1143 graph_next_line(graph, sb);
1144 return;
1145 }
1146
1147 /*
1148 * Output the row containing this commit
1149 * Iterate up to and including graph->num_columns,
1150 * since the current commit may not be in any of the existing
1151 * columns. (This happens when the current commit doesn't have any
1152 * children that we have already processed.)
1153 */
1154 for (i = 0; i < graph->num_columns; i++) {
1155 struct column *col = &graph->columns[i];
1156 strbuf_write_column(sb, col, '|');
1157 if (col->commit == graph->commit && graph->num_parents > 2)
1158 strbuf_addchars(sb, ' ', (graph->num_parents - 2) * 2);
1159 else
1160 strbuf_addch(sb, ' ');
1161 }
1162
1163 graph_pad_horizontally(graph, sb, graph->num_columns);
1164
1165 /*
1166 * Update graph->prev_state since we have output a padding line
1167 */
1168 graph->prev_state = GRAPH_PADDING;
1169 }
1170
1171 int graph_is_commit_finished(struct git_graph const *graph)
1172 {
1173 return (graph->state == GRAPH_PADDING);
1174 }
1175
1176 void graph_show_commit(struct git_graph *graph)
1177 {
1178 struct strbuf msgbuf = STRBUF_INIT;
1179 int shown_commit_line = 0;
1180
1181 if (!graph)
1182 return;
1183
1184 /*
1185 * When showing a diff of a merge against each of its parents, we
1186 * are called once for each parent without graph_update having been
1187 * called. In this case, simply output a single padding line.
1188 */
1189 if (graph_is_commit_finished(graph)) {
1190 graph_show_padding(graph);
1191 shown_commit_line = 1;
1192 }
1193
1194 while (!shown_commit_line && !graph_is_commit_finished(graph)) {
1195 shown_commit_line = graph_next_line(graph, &msgbuf);
1196 fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
1197 if (!shown_commit_line)
1198 putchar('\n');
1199 strbuf_setlen(&msgbuf, 0);
1200 }
1201
1202 strbuf_release(&msgbuf);
1203 }
1204
1205 void graph_show_oneline(struct git_graph *graph)
1206 {
1207 struct strbuf msgbuf = STRBUF_INIT;
1208
1209 if (!graph)
1210 return;
1211
1212 graph_next_line(graph, &msgbuf);
1213 fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
1214 strbuf_release(&msgbuf);
1215 }
1216
1217 void graph_show_padding(struct git_graph *graph)
1218 {
1219 struct strbuf msgbuf = STRBUF_INIT;
1220
1221 if (!graph)
1222 return;
1223
1224 graph_padding_line(graph, &msgbuf);
1225 fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
1226 strbuf_release(&msgbuf);
1227 }
1228
1229 int graph_show_remainder(struct git_graph *graph)
1230 {
1231 struct strbuf msgbuf = STRBUF_INIT;
1232 int shown = 0;
1233
1234 if (!graph)
1235 return 0;
1236
1237 if (graph_is_commit_finished(graph))
1238 return 0;
1239
1240 for (;;) {
1241 graph_next_line(graph, &msgbuf);
1242 fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
1243 strbuf_setlen(&msgbuf, 0);
1244 shown = 1;
1245
1246 if (!graph_is_commit_finished(graph))
1247 putchar('\n');
1248 else
1249 break;
1250 }
1251 strbuf_release(&msgbuf);
1252
1253 return shown;
1254 }
1255
1256
1257 static void graph_show_strbuf(struct git_graph *graph, struct strbuf const *sb)
1258 {
1259 char *p;
1260
1261 if (!graph) {
1262 fwrite(sb->buf, sizeof(char), sb->len, stdout);
1263 return;
1264 }
1265
1266 /*
1267 * Print the strbuf line by line,
1268 * and display the graph info before each line but the first.
1269 */
1270 p = sb->buf;
1271 while (p) {
1272 size_t len;
1273 char *next_p = strchr(p, '\n');
1274 if (next_p) {
1275 next_p++;
1276 len = next_p - p;
1277 } else {
1278 len = (sb->buf + sb->len) - p;
1279 }
1280 fwrite(p, sizeof(char), len, stdout);
1281 if (next_p && *next_p != '\0')
1282 graph_show_oneline(graph);
1283 p = next_p;
1284 }
1285 }
1286
1287 void graph_show_commit_msg(struct git_graph *graph,
1288 struct strbuf const *sb)
1289 {
1290 int newline_terminated;
1291
1292 if (!graph) {
1293 /*
1294 * If there's no graph, just print the message buffer.
1295 *
1296 * The message buffer for CMIT_FMT_ONELINE and
1297 * CMIT_FMT_USERFORMAT are already missing a terminating
1298 * newline. All of the other formats should have it.
1299 */
1300 fwrite(sb->buf, sizeof(char), sb->len, stdout);
1301 return;
1302 }
1303
1304 newline_terminated = (sb->len && sb->buf[sb->len - 1] == '\n');
1305
1306 /*
1307 * Show the commit message
1308 */
1309 graph_show_strbuf(graph, sb);
1310
1311 /*
1312 * If there is more output needed for this commit, show it now
1313 */
1314 if (!graph_is_commit_finished(graph)) {
1315 /*
1316 * If sb doesn't have a terminating newline, print one now,
1317 * so we can start the remainder of the graph output on a
1318 * new line.
1319 */
1320 if (!newline_terminated)
1321 putchar('\n');
1322
1323 graph_show_remainder(graph);
1324
1325 /*
1326 * If sb ends with a newline, our output should too.
1327 */
1328 if (newline_terminated)
1329 putchar('\n');
1330 }
1331 }