1 #include "cache.h"
2 #include "config.h"
3 #include "commit.h"
4 #include "color.h"
5 #include "graph.h"
6 #include "revision.h"
7 #include "strvec.h"
8 
9 /* Internal API */
10 
11 /*
12  * Output a padding line in the graph.
13  * This is similar to graph_next_line().  However, it is guaranteed to
14  * never print the current commit line.  Instead, if the commit line is
15  * next, it will simply output a line of vertical padding, extending the
16  * branch lines downwards, but leaving them otherwise unchanged.
17  */
18 static void graph_padding_line(struct git_graph *graph, struct strbuf *sb);
19 
20 /*
21  * Print a strbuf.  If the graph is non-NULL, all lines but the first will be
22  * prefixed with the graph output.
23  *
24  * If the strbuf ends with a newline, the output will end after this
25  * newline.  A new graph line will not be printed after the final newline.
26  * If the strbuf is empty, no output will be printed.
27  *
28  * Since the first line will not include the graph output, the caller is
29  * responsible for printing this line's graph (perhaps via
30  * graph_show_commit() or graph_show_oneline()) before calling
31  * graph_show_strbuf().
32  *
33  * Note that unlike some other graph display functions, you must pass the file
34  * handle directly. It is assumed that this is the same file handle as the
35  * file specified by the graph diff options. This is necessary so that
36  * graph_show_strbuf can be called even with a NULL graph.
37  * If a NULL graph is supplied, the strbuf is printed as-is.
38  */
39 static void graph_show_strbuf(struct git_graph *graph,
40 			      FILE *file,
41 			      struct strbuf const *sb);
42 
43 /*
44  * TODO:
45  * - Limit the number of columns, similar to the way gitk does.
46  *   If we reach more than a specified number of columns, omit
47  *   sections of some columns.
48  */
49 
50 struct column {
51 	/*
52 	 * The parent commit of this column.
53 	 */
54 	struct commit *commit;
55 	/*
56 	 * The color to (optionally) print this column in.  This is an
57 	 * index into column_colors.
58 	 */
59 	unsigned short color;
60 };
61 
62 enum graph_state {
63 	GRAPH_PADDING,
64 	GRAPH_SKIP,
65 	GRAPH_PRE_COMMIT,
66 	GRAPH_COMMIT,
67 	GRAPH_POST_MERGE,
68 	GRAPH_COLLAPSING
69 };
70 
71 static void graph_show_line_prefix(const struct diff_options *diffopt)
72 {
73 	if (!diffopt || !diffopt->line_prefix)
74 		return;
75 
76 	fwrite(diffopt->line_prefix,
77 	       sizeof(char),
78 	       diffopt->line_prefix_length,
79 	       diffopt->file);
80 }
81 
82 static const char **column_colors;
83 static unsigned short column_colors_max;
84 
85 static void parse_graph_colors_config(struct strvec *colors, const char *string)
86 {
87 	const char *end, *start;
88 
89 	start = string;
90 	end = string + strlen(string);
91 	while (start < end) {
92 		const char *comma = strchrnul(start, ',');
93 		char color[COLOR_MAXLEN];
94 
95 		if (!color_parse_mem(start, comma - start, color))
96 			strvec_push(colors, color);
97 		else
98 			warning(_("ignored invalid color '%.*s' in log.graphColors"),
99 				(int)(comma - start), start);
100 		start = comma + 1;
101 	}
102 	strvec_push(colors, GIT_COLOR_RESET);
103 }
104 
105 void graph_set_column_colors(const char **colors, unsigned short colors_max)
106 {
107 	column_colors = colors;
108 	column_colors_max = colors_max;
109 }
110 
111 static const char *column_get_color_code(unsigned short color)
112 {
113 	return column_colors[color];
114 }
115 
116 struct graph_line {
117 	struct strbuf *buf;
118 	size_t width;
119 };
120 
121 static inline void graph_line_addch(struct graph_line *line, int c)
122 {
123 	strbuf_addch(line->buf, c);
124 	line->width++;
125 }
126 
127 static inline void graph_line_addchars(struct graph_line *line, int c, size_t n)
128 {
129 	strbuf_addchars(line->buf, c, n);
130 	line->width += n;
131 }
132 
133 static inline void graph_line_addstr(struct graph_line *line, const char *s)
134 {
135 	strbuf_addstr(line->buf, s);
136 	line->width += strlen(s);
137 }
138 
139 static inline void graph_line_addcolor(struct graph_line *line, unsigned short color)
140 {
141 	strbuf_addstr(line->buf, column_get_color_code(color));
142 }
143 
144 static void graph_line_write_column(struct graph_line *line, const struct column *c,
145 				    char col_char)
146 {
147 	if (c->color < column_colors_max)
148 		graph_line_addcolor(line, c->color);
149 	graph_line_addch(line, col_char);
150 	if (c->color < column_colors_max)
151 		graph_line_addcolor(line, column_colors_max);
152 }
153 
154 struct git_graph {
155 	/*
156 	 * The commit currently being processed
157 	 */
158 	struct commit *commit;
159 	/* The rev-info used for the current traversal */
160 	struct rev_info *revs;
161 	/*
162 	 * The number of interesting parents that this commit has.
163 	 *
164 	 * Note that this is not the same as the actual number of parents.
165 	 * This count excludes parents that won't be printed in the graph
166 	 * output, as determined by graph_is_interesting().
167 	 */
168 	int num_parents;
169 	/*
170 	 * The width of the graph output for this commit.
171 	 * All rows for this commit are padded to this width, so that
172 	 * messages printed after the graph output are aligned.
173 	 */
174 	int width;
175 	/*
176 	 * The next expansion row to print
177 	 * when state is GRAPH_PRE_COMMIT
178 	 */
179 	int expansion_row;
180 	/*
181 	 * The current output state.
182 	 * This tells us what kind of line graph_next_line() should output.
183 	 */
184 	enum graph_state state;
185 	/*
186 	 * The output state for the previous line of output.
187 	 * This is primarily used to determine how the first merge line
188 	 * should appear, based on the last line of the previous commit.
189 	 */
190 	enum graph_state prev_state;
191 	/*
192 	 * The index of the column that refers to this commit.
193 	 *
194 	 * If none of the incoming columns refer to this commit,
195 	 * this will be equal to num_columns.
196 	 */
197 	int commit_index;
198 	/*
199 	 * The commit_index for the previously displayed commit.
200 	 *
201 	 * This is used to determine how the first line of a merge
202 	 * graph output should appear, based on the last line of the
203 	 * previous commit.
204 	 */
205 	int prev_commit_index;
206 	/*
207 	 * Which layout variant to use to display merge commits. If the
208 	 * commit's first parent is known to be in a column to the left of the
209 	 * merge, then this value is 0 and we use the layout on the left.
210 	 * Otherwise, the value is 1 and the layout on the right is used. This
211 	 * field tells us how many columns the first parent occupies.
212 	 *
213 	 * 		0)			1)
214 	 *
215 	 * 		| | | *-.		| | *---.
216 	 * 		| |_|/|\ \		| | |\ \ \
217 	 * 		|/| | | | |		| | | | | *
218 	 */
219 	int merge_layout;
220 	/*
221 	 * The number of columns added to the graph by the current commit. For
222 	 * 2-way and octopus merges, this is usually one less than the
223 	 * number of parents:
224 	 *
225 	 * 		| | |			| |    \
226 	 *		| * |			| *---. \
227 	 *		| |\ \			| |\ \ \ \
228 	 *		| | | |         	| | | | | |
229 	 *
230 	 *		num_parents: 2		num_parents: 4
231 	 *		edges_added: 1		edges_added: 3
232 	 *
233 	 * For left-skewed merges, the first parent fuses with its neighbor and
234 	 * so one less column is added:
235 	 *
236 	 *		| | |			| |  \
237 	 *		| * |			| *-. \
238 	 *		|/| |			|/|\ \ \
239 	 *		| | |			| | | | |
240 	 *
241 	 *		num_parents: 2		num_parents: 4
242 	 *		edges_added: 0		edges_added: 2
243 	 *
244 	 * This number determines how edges to the right of the merge are
245 	 * displayed in commit and post-merge lines; if no columns have been
246 	 * added then a vertical line should be used where a right-tracking
247 	 * line would otherwise be used.
248 	 *
249 	 *		| * \			| * |
250 	 *		| |\ \			|/| |
251 	 *		| | * \			| * |
252 	 */
253 	int edges_added;
254 	/*
255 	 * The number of columns added by the previous commit, which is used to
256 	 * smooth edges appearing to the right of a commit in a commit line
257 	 * following a post-merge line.
258 	 */
259 	int prev_edges_added;
260 	/*
261 	 * The maximum number of columns that can be stored in the columns
262 	 * and new_columns arrays.  This is also half the number of entries
263 	 * that can be stored in the mapping and old_mapping arrays.
264 	 */
265 	int column_capacity;
266 	/*
267 	 * The number of columns (also called "branch lines" in some places)
268 	 */
269 	int num_columns;
270 	/*
271 	 * The number of columns in the new_columns array
272 	 */
273 	int num_new_columns;
274 	/*
275 	 * The number of entries in the mapping array
276 	 */
277 	int mapping_size;
278 	/*
279 	 * The column state before we output the current commit.
280 	 */
281 	struct column *columns;
282 	/*
283 	 * The new column state after we output the current commit.
284 	 * Only valid when state is GRAPH_COLLAPSING.
285 	 */
286 	struct column *new_columns;
287 	/*
288 	 * An array that tracks the current state of each
289 	 * character in the output line during state GRAPH_COLLAPSING.
290 	 * Each entry is -1 if this character is empty, or a non-negative
291 	 * integer if the character contains a branch line.  The value of
292 	 * the integer indicates the target position for this branch line.
293 	 * (I.e., this array maps the current column positions to their
294 	 * desired positions.)
295 	 *
296 	 * The maximum capacity of this array is always
297 	 * sizeof(int) * 2 * column_capacity.
298 	 */
299 	int *mapping;
300 	/*
301 	 * A copy of the contents of the mapping array from the last commit,
302 	 * which we use to improve the display of columns that are tracking
303 	 * from right to left through a commit line.  We also use this to
304 	 * avoid allocating a fresh array when we compute the next mapping.
305 	 */
306 	int *old_mapping;
307 	/*
308 	 * The current default column color being used.  This is
309 	 * stored as an index into the array column_colors.
310 	 */
311 	unsigned short default_column_color;
312 };
313 
314 static struct strbuf *diff_output_prefix_callback(struct diff_options *opt, void *data)
315 {
316 	struct git_graph *graph = data;
317 	static struct strbuf msgbuf = STRBUF_INIT;
318 
319 	assert(opt);
320 
321 	strbuf_reset(&msgbuf);
322 	if (opt->line_prefix)
323 		strbuf_add(&msgbuf, opt->line_prefix,
324 			   opt->line_prefix_length);
325 	if (graph)
326 		graph_padding_line(graph, &msgbuf);
327 	return &msgbuf;
328 }
329 
330 static const struct diff_options *default_diffopt;
331 
332 void graph_setup_line_prefix(struct diff_options *diffopt)
333 {
334 	default_diffopt = diffopt;
335 
336 	/* setup an output prefix callback if necessary */
337 	if (diffopt && !diffopt->output_prefix)
338 		diffopt->output_prefix = diff_output_prefix_callback;
339 }
340 
341 
342 struct git_graph *graph_init(struct rev_info *opt)
343 {
344 	struct git_graph *graph = xmalloc(sizeof(struct git_graph));
345 
346 	if (!column_colors) {
347 		char *string;
348 		if (git_config_get_string("log.graphcolors", &string)) {
349 			/* not configured -- use default */
350 			graph_set_column_colors(column_colors_ansi,
351 						column_colors_ansi_max);
352 		} else {
353 			static struct strvec custom_colors = STRVEC_INIT;
354 			strvec_clear(&custom_colors);
355 			parse_graph_colors_config(&custom_colors, string);
356 			free(string);
357 			/* graph_set_column_colors takes a max-index, not a count */
358 			graph_set_column_colors(custom_colors.v,
359 						custom_colors.nr - 1);
360 		}
361 	}
362 
363 	graph->commit = NULL;
364 	graph->revs = opt;
365 	graph->num_parents = 0;
366 	graph->expansion_row = 0;
367 	graph->state = GRAPH_PADDING;
368 	graph->prev_state = GRAPH_PADDING;
369 	graph->commit_index = 0;
370 	graph->prev_commit_index = 0;
371 	graph->merge_layout = 0;
372 	graph->edges_added = 0;
373 	graph->prev_edges_added = 0;
374 	graph->num_columns = 0;
375 	graph->num_new_columns = 0;
376 	graph->mapping_size = 0;
377 	/*
378 	 * Start the column color at the maximum value, since we'll
379 	 * always increment it for the first commit we output.
380 	 * This way we start at 0 for the first commit.
381 	 */
382 	graph->default_column_color = column_colors_max - 1;
383 
384 	/*
385 	 * Allocate a reasonably large default number of columns
386 	 * We'll automatically grow columns later if we need more room.
387 	 */
388 	graph->column_capacity = 30;
389 	ALLOC_ARRAY(graph->columns, graph->column_capacity);
390 	ALLOC_ARRAY(graph->new_columns, graph->column_capacity);
391 	ALLOC_ARRAY(graph->mapping, 2 * graph->column_capacity);
392 	ALLOC_ARRAY(graph->old_mapping, 2 * graph->column_capacity);
393 
394 	/*
395 	 * The diff output prefix callback, with this we can make
396 	 * all the diff output to align with the graph lines.
397 	 */
398 	opt->diffopt.output_prefix = diff_output_prefix_callback;
399 	opt->diffopt.output_prefix_data = graph;
400 
401 	return graph;
402 }
403 
404 static void graph_update_state(struct git_graph *graph, enum graph_state s)
405 {
406 	graph->prev_state = graph->state;
407 	graph->state = s;
408 }
409 
410 static void graph_ensure_capacity(struct git_graph *graph, int num_columns)
411 {
412 	if (graph->column_capacity >= num_columns)
413 		return;
414 
415 	do {
416 		graph->column_capacity *= 2;
417 	} while (graph->column_capacity < num_columns);
418 
419 	REALLOC_ARRAY(graph->columns, graph->column_capacity);
420 	REALLOC_ARRAY(graph->new_columns, graph->column_capacity);
421 	REALLOC_ARRAY(graph->mapping, graph->column_capacity * 2);
422 	REALLOC_ARRAY(graph->old_mapping, graph->column_capacity * 2);
423 }
424 
425 /*
426  * Returns 1 if the commit will be printed in the graph output,
427  * and 0 otherwise.
428  */
429 static int graph_is_interesting(struct git_graph *graph, struct commit *commit)
430 {
431 	/*
432 	 * If revs->boundary is set, commits whose children have
433 	 * been shown are always interesting, even if they have the
434 	 * UNINTERESTING or TREESAME flags set.
435 	 */
436 	if (graph->revs && graph->revs->boundary) {
437 		if (commit->object.flags & CHILD_SHOWN)
438 			return 1;
439 	}
440 
441 	/*
442 	 * Otherwise, use get_commit_action() to see if this commit is
443 	 * interesting
444 	 */
445 	return get_commit_action(graph->revs, commit) == commit_show;
446 }
447 
448 static struct commit_list *next_interesting_parent(struct git_graph *graph,
449 						   struct commit_list *orig)
450 {
451 	struct commit_list *list;
452 
453 	/*
454 	 * If revs->first_parent_only is set, only the first
455 	 * parent is interesting.  None of the others are.
456 	 */
457 	if (graph->revs->first_parent_only)
458 		return NULL;
459 
460 	/*
461 	 * Return the next interesting commit after orig
462 	 */
463 	for (list = orig->next; list; list = list->next) {
464 		if (graph_is_interesting(graph, list->item))
465 			return list;
466 	}
467 
468 	return NULL;
469 }
470 
471 static struct commit_list *first_interesting_parent(struct git_graph *graph)
472 {
473 	struct commit_list *parents = graph->commit->parents;
474 
475 	/*
476 	 * If this commit has no parents, ignore it
477 	 */
478 	if (!parents)
479 		return NULL;
480 
481 	/*
482 	 * If the first parent is interesting, return it
483 	 */
484 	if (graph_is_interesting(graph, parents->item))
485 		return parents;
486 
487 	/*
488 	 * Otherwise, call next_interesting_parent() to get
489 	 * the next interesting parent
490 	 */
491 	return next_interesting_parent(graph, parents);
492 }
493 
494 static unsigned short graph_get_current_column_color(const struct git_graph *graph)
495 {
496 	if (!want_color(graph->revs->diffopt.use_color))
497 		return column_colors_max;
498 	return graph->default_column_color;
499 }
500 
501 /*
502  * Update the graph's default column color.
503  */
504 static void graph_increment_column_color(struct git_graph *graph)
505 {
506 	graph->default_column_color = (graph->default_column_color + 1) %
507 		column_colors_max;
508 }
509 
510 static unsigned short graph_find_commit_color(const struct git_graph *graph,
511 					      const struct commit *commit)
512 {
513 	int i;
514 	for (i = 0; i < graph->num_columns; i++) {
515 		if (graph->columns[i].commit == commit)
516 			return graph->columns[i].color;
517 	}
518 	return graph_get_current_column_color(graph);
519 }
520 
521 static int graph_find_new_column_by_commit(struct git_graph *graph,
522 					   struct commit *commit)
523 {
524 	int i;
525 	for (i = 0; i < graph->num_new_columns; i++) {
526 		if (graph->new_columns[i].commit == commit)
527 			return i;
528 	}
529 	return -1;
530 }
531 
532 static void graph_insert_into_new_columns(struct git_graph *graph,
533 					  struct commit *commit,
534 					  int idx)
535 {
536 	int i = graph_find_new_column_by_commit(graph, commit);
537 	int mapping_idx;
538 
539 	/*
540 	 * If the commit is not already in the new_columns array, then add it
541 	 * and record it as being in the final column.
542 	 */
543 	if (i < 0) {
544 		i = graph->num_new_columns++;
545 		graph->new_columns[i].commit = commit;
546 		graph->new_columns[i].color = graph_find_commit_color(graph, commit);
547 	}
548 
549 	if (graph->num_parents > 1 && idx > -1 && graph->merge_layout == -1) {
550 		/*
551 		 * If this is the first parent of a merge, choose a layout for
552 		 * the merge line based on whether the parent appears in a
553 		 * column to the left of the merge
554 		 */
555 		int dist, shift;
556 
557 		dist = idx - i;
558 		shift = (dist > 1) ? 2 * dist - 3 : 1;
559 
560 		graph->merge_layout = (dist > 0) ? 0 : 1;
561 		graph->edges_added = graph->num_parents + graph->merge_layout  - 2;
562 
563 		mapping_idx = graph->width + (graph->merge_layout - 1) * shift;
564 		graph->width += 2 * graph->merge_layout;
565 
566 	} else if (graph->edges_added > 0 && i == graph->mapping[graph->width - 2]) {
567 		/*
568 		 * If some columns have been added by a merge, but this commit
569 		 * was found in the last existing column, then adjust the
570 		 * numbers so that the two edges immediately join, i.e.:
571 		 *
572 		 *		* |		* |
573 		 *		|\ \	=>	|\|
574 		 *		| |/		| *
575 		 *		| *
576 		 */
577 		mapping_idx = graph->width - 2;
578 		graph->edges_added = -1;
579 	} else {
580 		mapping_idx = graph->width;
581 		graph->width += 2;
582 	}
583 
584 	graph->mapping[mapping_idx] = i;
585 }
586 
587 static void graph_update_columns(struct git_graph *graph)
588 {
589 	struct commit_list *parent;
590 	int max_new_columns;
591 	int i, seen_this, is_commit_in_columns;
592 
593 	/*
594 	 * Swap graph->columns with graph->new_columns
595 	 * graph->columns contains the state for the previous commit,
596 	 * and new_columns now contains the state for our commit.
597 	 *
598 	 * We'll re-use the old columns array as storage to compute the new
599 	 * columns list for the commit after this one.
600 	 */
601 	SWAP(graph->columns, graph->new_columns);
602 	graph->num_columns = graph->num_new_columns;
603 	graph->num_new_columns = 0;
604 
605 	/*
606 	 * Now update new_columns and mapping with the information for the
607 	 * commit after this one.
608 	 *
609 	 * First, make sure we have enough room.  At most, there will
610 	 * be graph->num_columns + graph->num_parents columns for the next
611 	 * commit.
612 	 */
613 	max_new_columns = graph->num_columns + graph->num_parents;
614 	graph_ensure_capacity(graph, max_new_columns);
615 
616 	/*
617 	 * Clear out graph->mapping
618 	 */
619 	graph->mapping_size = 2 * max_new_columns;
620 	for (i = 0; i < graph->mapping_size; i++)
621 		graph->mapping[i] = -1;
622 
623 	graph->width = 0;
624 	graph->prev_edges_added = graph->edges_added;
625 	graph->edges_added = 0;
626 
627 	/*
628 	 * Populate graph->new_columns and graph->mapping
629 	 *
630 	 * Some of the parents of this commit may already be in
631 	 * graph->columns.  If so, graph->new_columns should only contain a
632 	 * single entry for each such commit.  graph->mapping should
633 	 * contain information about where each current branch line is
634 	 * supposed to end up after the collapsing is performed.
635 	 */
636 	seen_this = 0;
637 	is_commit_in_columns = 1;
638 	for (i = 0; i <= graph->num_columns; i++) {
639 		struct commit *col_commit;
640 		if (i == graph->num_columns) {
641 			if (seen_this)
642 				break;
643 			is_commit_in_columns = 0;
644 			col_commit = graph->commit;
645 		} else {
646 			col_commit = graph->columns[i].commit;
647 		}
648 
649 		if (col_commit == graph->commit) {
650 			seen_this = 1;
651 			graph->commit_index = i;
652 			graph->merge_layout = -1;
653 			for (parent = first_interesting_parent(graph);
654 			     parent;
655 			     parent = next_interesting_parent(graph, parent)) {
656 				/*
657 				 * If this is a merge, or the start of a new
658 				 * childless column, increment the current
659 				 * color.
660 				 */
661 				if (graph->num_parents > 1 ||
662 				    !is_commit_in_columns) {
663 					graph_increment_column_color(graph);
664 				}
665 				graph_insert_into_new_columns(graph, parent->item, i);
666 			}
667 			/*
668 			 * We always need to increment graph->width by at
669 			 * least 2, even if it has no interesting parents.
670 			 * The current commit always takes up at least 2
671 			 * spaces.
672 			 */
673 			if (graph->num_parents == 0)
674 				graph->width += 2;
675 		} else {
676 			graph_insert_into_new_columns(graph, col_commit, -1);
677 		}
678 	}
679 
680 	/*
681 	 * Shrink mapping_size to be the minimum necessary
682 	 */
683 	while (graph->mapping_size > 1 &&
684 	       graph->mapping[graph->mapping_size - 1] < 0)
685 		graph->mapping_size--;
686 }
687 
688 static int graph_num_dashed_parents(struct git_graph *graph)
689 {
690 	return graph->num_parents + graph->merge_layout - 3;
691 }
692 
693 static int graph_num_expansion_rows(struct git_graph *graph)
694 {
695 	/*
696 	 * Normally, we need two expansion rows for each dashed parent line from
697 	 * an octopus merge:
698 	 *
699 	 * 		| *
700 	 * 		| |\
701 	 * 		| | \
702 	 * 		| |  \
703 	 * 		| *-. \
704 	 * 		| |\ \ \
705 	 *
706 	 * If the merge is skewed to the left, then its parents occupy one less
707 	 * column, and we don't need as many expansion rows to route around it;
708 	 * in some cases that means we don't need any expansion rows at all:
709 	 *
710 	 * 		| *
711 	 * 		| |\
712 	 * 		| * \
713 	 * 		|/|\ \
714 	 */
715 	return graph_num_dashed_parents(graph) * 2;
716 }
717 
718 static int graph_needs_pre_commit_line(struct git_graph *graph)
719 {
720 	return graph->num_parents >= 3 &&
721 	       graph->commit_index < (graph->num_columns - 1) &&
722 	       graph->expansion_row < graph_num_expansion_rows(graph);
723 }
724 
725 void graph_update(struct git_graph *graph, struct commit *commit)
726 {
727 	struct commit_list *parent;
728 
729 	/*
730 	 * Set the new commit
731 	 */
732 	graph->commit = commit;
733 
734 	/*
735 	 * Count how many interesting parents this commit has
736 	 */
737 	graph->num_parents = 0;
738 	for (parent = first_interesting_parent(graph);
739 	     parent;
740 	     parent = next_interesting_parent(graph, parent))
741 	{
742 		graph->num_parents++;
743 	}
744 
745 	/*
746 	 * Store the old commit_index in prev_commit_index.
747 	 * graph_update_columns() will update graph->commit_index for this
748 	 * commit.
749 	 */
750 	graph->prev_commit_index = graph->commit_index;
751 
752 	/*
753 	 * Call graph_update_columns() to update
754 	 * columns, new_columns, and mapping.
755 	 */
756 	graph_update_columns(graph);
757 
758 	graph->expansion_row = 0;
759 
760 	/*
761 	 * Update graph->state.
762 	 * Note that we don't call graph_update_state() here, since
763 	 * we don't want to update graph->prev_state.  No line for
764 	 * graph->state was ever printed.
765 	 *
766 	 * If the previous commit didn't get to the GRAPH_PADDING state,
767 	 * it never finished its output.  Goto GRAPH_SKIP, to print out
768 	 * a line to indicate that portion of the graph is missing.
769 	 *
770 	 * If there are 3 or more parents, we may need to print extra rows
771 	 * before the commit, to expand the branch lines around it and make
772 	 * room for it.  We need to do this only if there is a branch row
773 	 * (or more) to the right of this commit.
774 	 *
775 	 * If there are less than 3 parents, we can immediately print the
776 	 * commit line.
777 	 */
778 	if (graph->state != GRAPH_PADDING)
779 		graph->state = GRAPH_SKIP;
780 	else if (graph_needs_pre_commit_line(graph))
781 		graph->state = GRAPH_PRE_COMMIT;
782 	else
783 		graph->state = GRAPH_COMMIT;
784 }
785 
786 static int graph_is_mapping_correct(struct git_graph *graph)
787 {
788 	int i;
789 
790 	/*
791 	 * The mapping is up to date if each entry is at its target,
792 	 * or is 1 greater than its target.
793 	 * (If it is 1 greater than the target, '/' will be printed, so it
794 	 * will look correct on the next row.)
795 	 */
796 	for (i = 0; i < graph->mapping_size; i++) {
797 		int target = graph->mapping[i];
798 		if (target < 0)
799 			continue;
800 		if (target == (i / 2))
801 			continue;
802 		return 0;
803 	}
804 
805 	return 1;
806 }
807 
808 static void graph_pad_horizontally(struct git_graph *graph, struct graph_line *line)
809 {
810 	/*
811 	 * Add additional spaces to the end of the strbuf, so that all
812 	 * lines for a particular commit have the same width.
813 	 *
814 	 * This way, fields printed to the right of the graph will remain
815 	 * aligned for the entire commit.
816 	 */
817 	if (line->width < graph->width)
818 		graph_line_addchars(line, ' ', graph->width - line->width);
819 }
820 
821 static void graph_output_padding_line(struct git_graph *graph,
822 				      struct graph_line *line)
823 {
824 	int i;
825 
826 	/*
827 	 * Output a padding row, that leaves all branch lines unchanged
828 	 */
829 	for (i = 0; i < graph->num_new_columns; i++) {
830 		graph_line_write_column(line, &graph->new_columns[i], '|');
831 		graph_line_addch(line, ' ');
832 	}
833 }
834 
835 
836 int graph_width(struct git_graph *graph)
837 {
838 	return graph->width;
839 }
840 
841 
842 static void graph_output_skip_line(struct git_graph *graph, struct graph_line *line)
843 {
844 	/*
845 	 * Output an ellipsis to indicate that a portion
846 	 * of the graph is missing.
847 	 */
848 	graph_line_addstr(line, "...");
849 
850 	if (graph_needs_pre_commit_line(graph))
851 		graph_update_state(graph, GRAPH_PRE_COMMIT);
852 	else
853 		graph_update_state(graph, GRAPH_COMMIT);
854 }
855 
856 static void graph_output_pre_commit_line(struct git_graph *graph,
857 					 struct graph_line *line)
858 {
859 	int i, seen_this;
860 
861 	/*
862 	 * This function formats a row that increases the space around a commit
863 	 * with multiple parents, to make room for it.  It should only be
864 	 * called when there are 3 or more parents.
865 	 *
866 	 * We need 2 extra rows for every parent over 2.
867 	 */
868 	assert(graph->num_parents >= 3);
869 
870 	/*
871 	 * graph->expansion_row tracks the current expansion row we are on.
872 	 * It should be in the range [0, num_expansion_rows - 1]
873 	 */
874 	assert(0 <= graph->expansion_row &&
875 	       graph->expansion_row < graph_num_expansion_rows(graph));
876 
877 	/*
878 	 * Output the row
879 	 */
880 	seen_this = 0;
881 	for (i = 0; i < graph->num_columns; i++) {
882 		struct column *col = &graph->columns[i];
883 		if (col->commit == graph->commit) {
884 			seen_this = 1;
885 			graph_line_write_column(line, col, '|');
886 			graph_line_addchars(line, ' ', graph->expansion_row);
887 		} else if (seen_this && (graph->expansion_row == 0)) {
888 			/*
889 			 * This is the first line of the pre-commit output.
890 			 * If the previous commit was a merge commit and
891 			 * ended in the GRAPH_POST_MERGE state, all branch
892 			 * lines after graph->prev_commit_index were
893 			 * printed as "\" on the previous line.  Continue
894 			 * to print them as "\" on this line.  Otherwise,
895 			 * print the branch lines as "|".
896 			 */
897 			if (graph->prev_state == GRAPH_POST_MERGE &&
898 			    graph->prev_commit_index < i)
899 				graph_line_write_column(line, col, '\\');
900 			else
901 				graph_line_write_column(line, col, '|');
902 		} else if (seen_this && (graph->expansion_row > 0)) {
903 			graph_line_write_column(line, col, '\\');
904 		} else {
905 			graph_line_write_column(line, col, '|');
906 		}
907 		graph_line_addch(line, ' ');
908 	}
909 
910 	/*
911 	 * Increment graph->expansion_row,
912 	 * and move to state GRAPH_COMMIT if necessary
913 	 */
914 	graph->expansion_row++;
915 	if (!graph_needs_pre_commit_line(graph))
916 		graph_update_state(graph, GRAPH_COMMIT);
917 }
918 
919 static void graph_output_commit_char(struct git_graph *graph, struct graph_line *line)
920 {
921 	/*
922 	 * For boundary commits, print 'o'
923 	 * (We should only see boundary commits when revs->boundary is set.)
924 	 */
925 	if (graph->commit->object.flags & BOUNDARY) {
926 		assert(graph->revs->boundary);
927 		graph_line_addch(line, 'o');
928 		return;
929 	}
930 
931 	/*
932 	 * get_revision_mark() handles all other cases without assert()
933 	 */
934 	graph_line_addstr(line, get_revision_mark(graph->revs, graph->commit));
935 }
936 
937 /*
938  * Draw the horizontal dashes of an octopus merge.
939  */
940 static void graph_draw_octopus_merge(struct git_graph *graph, struct graph_line *line)
941 {
942 	/*
943 	 * The parents of a merge commit can be arbitrarily reordered as they
944 	 * are mapped onto display columns, for example this is a valid merge:
945 	 *
946 	 *	| | *---.
947 	 *	| | |\ \ \
948 	 *	| | |/ / /
949 	 *	| |/| | /
950 	 *	| |_|_|/
951 	 *	|/| | |
952 	 *	3 1 0 2
953 	 *
954 	 * The numbers denote which parent of the merge each visual column
955 	 * corresponds to; we can't assume that the parents will initially
956 	 * display in the order given by new_columns.
957 	 *
958 	 * To find the right color for each dash, we need to consult the
959 	 * mapping array, starting from the column 2 places to the right of the
960 	 * merge commit, and use that to find out which logical column each
961 	 * edge will collapse to.
962 	 *
963 	 * Commits are rendered once all edges have collapsed to their correct
964 	 * logcial column, so commit_index gives us the right visual offset for
965 	 * the merge commit.
966 	 */
967 
968 	int i, j;
969 	struct column *col;
970 
971 	int dashed_parents = graph_num_dashed_parents(graph);
972 
973 	for (i = 0; i < dashed_parents; i++) {
974 		j = graph->mapping[(graph->commit_index + i + 2) * 2];
975 		col = &graph->new_columns[j];
976 
977 		graph_line_write_column(line, col, '-');
978 		graph_line_write_column(line, col, (i == dashed_parents - 1) ? '.' : '-');
979 	}
980 
981 	return;
982 }
983 
984 static void graph_output_commit_line(struct git_graph *graph, struct graph_line *line)
985 {
986 	int seen_this = 0;
987 	int i;
988 
989 	/*
990 	 * Output the row containing this commit
991 	 * Iterate up to and including graph->num_columns,
992 	 * since the current commit may not be in any of the existing
993 	 * columns.  (This happens when the current commit doesn't have any
994 	 * children that we have already processed.)
995 	 */
996 	seen_this = 0;
997 	for (i = 0; i <= graph->num_columns; i++) {
998 		struct column *col = &graph->columns[i];
999 		struct commit *col_commit;
1000 		if (i == graph->num_columns) {
1001 			if (seen_this)
1002 				break;
1003 			col_commit = graph->commit;
1004 		} else {
1005 			col_commit = graph->columns[i].commit;
1006 		}
1007 
1008 		if (col_commit == graph->commit) {
1009 			seen_this = 1;
1010 			graph_output_commit_char(graph, line);
1011 
1012 			if (graph->num_parents > 2)
1013 				graph_draw_octopus_merge(graph, line);
1014 		} else if (seen_this && (graph->edges_added > 1)) {
1015 			graph_line_write_column(line, col, '\\');
1016 		} else if (seen_this && (graph->edges_added == 1)) {
1017 			/*
1018 			 * This is either a right-skewed 2-way merge
1019 			 * commit, or a left-skewed 3-way merge.
1020 			 * There is no GRAPH_PRE_COMMIT stage for such
1021 			 * merges, so this is the first line of output
1022 			 * for this commit.  Check to see what the previous
1023 			 * line of output was.
1024 			 *
1025 			 * If it was GRAPH_POST_MERGE, the branch line
1026 			 * coming into this commit may have been '\',
1027 			 * and not '|' or '/'.  If so, output the branch
1028 			 * line as '\' on this line, instead of '|'.  This
1029 			 * makes the output look nicer.
1030 			 */
1031 			if (graph->prev_state == GRAPH_POST_MERGE &&
1032 			    graph->prev_edges_added > 0 &&
1033 			    graph->prev_commit_index < i)
1034 				graph_line_write_column(line, col, '\\');
1035 			else
1036 				graph_line_write_column(line, col, '|');
1037 		} else if (graph->prev_state == GRAPH_COLLAPSING &&
1038 			   graph->old_mapping[2 * i + 1] == i &&
1039 			   graph->mapping[2 * i] < i) {
1040 			graph_line_write_column(line, col, '/');
1041 		} else {
1042 			graph_line_write_column(line, col, '|');
1043 		}
1044 		graph_line_addch(line, ' ');
1045 	}
1046 
1047 	/*
1048 	 * Update graph->state
1049 	 */
1050 	if (graph->num_parents > 1)
1051 		graph_update_state(graph, GRAPH_POST_MERGE);
1052 	else if (graph_is_mapping_correct(graph))
1053 		graph_update_state(graph, GRAPH_PADDING);
1054 	else
1055 		graph_update_state(graph, GRAPH_COLLAPSING);
1056 }
1057 
1058 static const char merge_chars[] = {'/', '|', '\\'};
1059 
1060 static void graph_output_post_merge_line(struct git_graph *graph, struct graph_line *line)
1061 {
1062 	int seen_this = 0;
1063 	int i, j;
1064 
1065 	struct commit_list *first_parent = first_interesting_parent(graph);
1066 	struct column *parent_col = NULL;
1067 
1068 	/*
1069 	 * Output the post-merge row
1070 	 */
1071 	for (i = 0; i <= graph->num_columns; i++) {
1072 		struct column *col = &graph->columns[i];
1073 		struct commit *col_commit;
1074 		if (i == graph->num_columns) {
1075 			if (seen_this)
1076 				break;
1077 			col_commit = graph->commit;
1078 		} else {
1079 			col_commit = col->commit;
1080 		}
1081 
1082 		if (col_commit == graph->commit) {
1083 			/*
1084 			 * Since the current commit is a merge find
1085 			 * the columns for the parent commits in
1086 			 * new_columns and use those to format the
1087 			 * edges.
1088 			 */
1089 			struct commit_list *parents = first_parent;
1090 			int par_column;
1091 			int idx = graph->merge_layout;
1092 			char c;
1093 			seen_this = 1;
1094 
1095 			for (j = 0; j < graph->num_parents; j++) {
1096 				par_column = graph_find_new_column_by_commit(graph, parents->item);
1097 				assert(par_column >= 0);
1098 
1099 				c = merge_chars[idx];
1100 				graph_line_write_column(line, &graph->new_columns[par_column], c);
1101 				if (idx == 2) {
1102 					if (graph->edges_added > 0 || j < graph->num_parents - 1)
1103 						graph_line_addch(line, ' ');
1104 				} else {
1105 					idx++;
1106 				}
1107 				parents = next_interesting_parent(graph, parents);
1108 			}
1109 			if (graph->edges_added == 0)
1110 				graph_line_addch(line, ' ');
1111 
1112 		} else if (seen_this) {
1113 			if (graph->edges_added > 0)
1114 				graph_line_write_column(line, col, '\\');
1115 			else
1116 				graph_line_write_column(line, col, '|');
1117 			graph_line_addch(line, ' ');
1118 		} else {
1119 			graph_line_write_column(line, col, '|');
1120 			if (graph->merge_layout != 0 || i != graph->commit_index - 1) {
1121 				if (parent_col)
1122 					graph_line_write_column(
1123 						line, parent_col, '_');
1124 				else
1125 					graph_line_addch(line, ' ');
1126 			}
1127 		}
1128 
1129 		if (col_commit == first_parent->item)
1130 			parent_col = col;
1131 	}
1132 
1133 	/*
1134 	 * Update graph->state
1135 	 */
1136 	if (graph_is_mapping_correct(graph))
1137 		graph_update_state(graph, GRAPH_PADDING);
1138 	else
1139 		graph_update_state(graph, GRAPH_COLLAPSING);
1140 }
1141 
1142 static void graph_output_collapsing_line(struct git_graph *graph, struct graph_line *line)
1143 {
1144 	int i;
1145 	short used_horizontal = 0;
1146 	int horizontal_edge = -1;
1147 	int horizontal_edge_target = -1;
1148 
1149 	/*
1150 	 * Swap the mapping and old_mapping arrays
1151 	 */
1152 	SWAP(graph->mapping, graph->old_mapping);
1153 
1154 	/*
1155 	 * Clear out the mapping array
1156 	 */
1157 	for (i = 0; i < graph->mapping_size; i++)
1158 		graph->mapping[i] = -1;
1159 
1160 	for (i = 0; i < graph->mapping_size; i++) {
1161 		int target = graph->old_mapping[i];
1162 		if (target < 0)
1163 			continue;
1164 
1165 		/*
1166 		 * Since update_columns() always inserts the leftmost
1167 		 * column first, each branch's target location should
1168 		 * always be either its current location or to the left of
1169 		 * its current location.
1170 		 *
1171 		 * We never have to move branches to the right.  This makes
1172 		 * the graph much more legible, since whenever branches
1173 		 * cross, only one is moving directions.
1174 		 */
1175 		assert(target * 2 <= i);
1176 
1177 		if (target * 2 == i) {
1178 			/*
1179 			 * This column is already in the
1180 			 * correct place
1181 			 */
1182 			assert(graph->mapping[i] == -1);
1183 			graph->mapping[i] = target;
1184 		} else if (graph->mapping[i - 1] < 0) {
1185 			/*
1186 			 * Nothing is to the left.
1187 			 * Move to the left by one
1188 			 */
1189 			graph->mapping[i - 1] = target;
1190 			/*
1191 			 * If there isn't already an edge moving horizontally
1192 			 * select this one.
1193 			 */
1194 			if (horizontal_edge == -1) {
1195 				int j;
1196 				horizontal_edge = i;
1197 				horizontal_edge_target = target;
1198 				/*
1199 				 * The variable target is the index of the graph
1200 				 * column, and therefore target*2+3 is the
1201 				 * actual screen column of the first horizontal
1202 				 * line.
1203 				 */
1204 				for (j = (target * 2)+3; j < (i - 2); j += 2)
1205 					graph->mapping[j] = target;
1206 			}
1207 		} else if (graph->mapping[i - 1] == target) {
1208 			/*
1209 			 * There is a branch line to our left
1210 			 * already, and it is our target.  We
1211 			 * combine with this line, since we share
1212 			 * the same parent commit.
1213 			 *
1214 			 * We don't have to add anything to the
1215 			 * output or mapping, since the
1216 			 * existing branch line has already taken
1217 			 * care of it.
1218 			 */
1219 		} else {
1220 			/*
1221 			 * There is a branch line to our left,
1222 			 * but it isn't our target.  We need to
1223 			 * cross over it.
1224 			 *
1225 			 * The space just to the left of this
1226 			 * branch should always be empty.
1227 			 */
1228 			assert(graph->mapping[i - 1] > target);
1229 			assert(graph->mapping[i - 2] < 0);
1230 			graph->mapping[i - 2] = target;
1231 			/*
1232 			 * Mark this branch as the horizontal edge to
1233 			 * prevent any other edges from moving
1234 			 * horizontally.
1235 			 */
1236 			if (horizontal_edge == -1) {
1237 				int j;
1238 				horizontal_edge_target = target;
1239 				horizontal_edge = i - 1;
1240 
1241 				for (j = (target * 2) + 3; j < (i - 2); j += 2)
1242 					graph->mapping[j] = target;
1243 			}
1244 		}
1245 	}
1246 
1247 	/*
1248 	 * Copy the current mapping array into old_mapping
1249 	 */
1250 	COPY_ARRAY(graph->old_mapping, graph->mapping, graph->mapping_size);
1251 
1252 	/*
1253 	 * The new mapping may be 1 smaller than the old mapping
1254 	 */
1255 	if (graph->mapping[graph->mapping_size - 1] < 0)
1256 		graph->mapping_size--;
1257 
1258 	/*
1259 	 * Output out a line based on the new mapping info
1260 	 */
1261 	for (i = 0; i < graph->mapping_size; i++) {
1262 		int target = graph->mapping[i];
1263 		if (target < 0)
1264 			graph_line_addch(line, ' ');
1265 		else if (target * 2 == i)
1266 			graph_line_write_column(line, &graph->new_columns[target], '|');
1267 		else if (target == horizontal_edge_target &&
1268 			 i != horizontal_edge - 1) {
1269 				/*
1270 				 * Set the mappings for all but the
1271 				 * first segment to -1 so that they
1272 				 * won't continue into the next line.
1273 				 */
1274 				if (i != (target * 2)+3)
1275 					graph->mapping[i] = -1;
1276 				used_horizontal = 1;
1277 			graph_line_write_column(line, &graph->new_columns[target], '_');
1278 		} else {
1279 			if (used_horizontal && i < horizontal_edge)
1280 				graph->mapping[i] = -1;
1281 			graph_line_write_column(line, &graph->new_columns[target], '/');
1282 
1283 		}
1284 	}
1285 
1286 	/*
1287 	 * If graph->mapping indicates that all of the branch lines
1288 	 * are already in the correct positions, we are done.
1289 	 * Otherwise, we need to collapse some branch lines together.
1290 	 */
1291 	if (graph_is_mapping_correct(graph))
1292 		graph_update_state(graph, GRAPH_PADDING);
1293 }
1294 
1295 int graph_next_line(struct git_graph *graph, struct strbuf *sb)
1296 {
1297 	int shown_commit_line = 0;
1298 	struct graph_line line = { .buf = sb, .width = 0 };
1299 
1300 	/*
1301 	 * We could conceivable be called with a NULL commit
1302 	 * if our caller has a bug, and invokes graph_next_line()
1303 	 * immediately after graph_init(), without first calling
1304 	 * graph_update().  Return without outputting anything in this
1305 	 * case.
1306 	 */
1307 	if (!graph->commit)
1308 		return -1;
1309 
1310 	switch (graph->state) {
1311 	case GRAPH_PADDING:
1312 		graph_output_padding_line(graph, &line);
1313 		break;
1314 	case GRAPH_SKIP:
1315 		graph_output_skip_line(graph, &line);
1316 		break;
1317 	case GRAPH_PRE_COMMIT:
1318 		graph_output_pre_commit_line(graph, &line);
1319 		break;
1320 	case GRAPH_COMMIT:
1321 		graph_output_commit_line(graph, &line);
1322 		shown_commit_line = 1;
1323 		break;
1324 	case GRAPH_POST_MERGE:
1325 		graph_output_post_merge_line(graph, &line);
1326 		break;
1327 	case GRAPH_COLLAPSING:
1328 		graph_output_collapsing_line(graph, &line);
1329 		break;
1330 	}
1331 
1332 	graph_pad_horizontally(graph, &line);
1333 	return shown_commit_line;
1334 }
1335 
1336 static void graph_padding_line(struct git_graph *graph, struct strbuf *sb)
1337 {
1338 	int i;
1339 	struct graph_line line = { .buf = sb, .width = 0 };
1340 
1341 	if (graph->state != GRAPH_COMMIT) {
1342 		graph_next_line(graph, sb);
1343 		return;
1344 	}
1345 
1346 	/*
1347 	 * Output the row containing this commit
1348 	 * Iterate up to and including graph->num_columns,
1349 	 * since the current commit may not be in any of the existing
1350 	 * columns.  (This happens when the current commit doesn't have any
1351 	 * children that we have already processed.)
1352 	 */
1353 	for (i = 0; i < graph->num_columns; i++) {
1354 		struct column *col = &graph->columns[i];
1355 
1356 		graph_line_write_column(&line, col, '|');
1357 
1358 		if (col->commit == graph->commit && graph->num_parents > 2) {
1359 			int len = (graph->num_parents - 2) * 2;
1360 			graph_line_addchars(&line, ' ', len);
1361 		} else {
1362 			graph_line_addch(&line, ' ');
1363 		}
1364 	}
1365 
1366 	graph_pad_horizontally(graph, &line);
1367 
1368 	/*
1369 	 * Update graph->prev_state since we have output a padding line
1370 	 */
1371 	graph->prev_state = GRAPH_PADDING;
1372 }
1373 
1374 int graph_is_commit_finished(struct git_graph const *graph)
1375 {
1376 	return (graph->state == GRAPH_PADDING);
1377 }
1378 
1379 void graph_show_commit(struct git_graph *graph)
1380 {
1381 	struct strbuf msgbuf = STRBUF_INIT;
1382 	int shown_commit_line = 0;
1383 
1384 	graph_show_line_prefix(default_diffopt);
1385 
1386 	if (!graph)
1387 		return;
1388 
1389 	/*
1390 	 * When showing a diff of a merge against each of its parents, we
1391 	 * are called once for each parent without graph_update having been
1392 	 * called.  In this case, simply output a single padding line.
1393 	 */
1394 	if (graph_is_commit_finished(graph)) {
1395 		graph_show_padding(graph);
1396 		shown_commit_line = 1;
1397 	}
1398 
1399 	while (!shown_commit_line && !graph_is_commit_finished(graph)) {
1400 		shown_commit_line = graph_next_line(graph, &msgbuf);
1401 		fwrite(msgbuf.buf, sizeof(char), msgbuf.len,
1402 			graph->revs->diffopt.file);
1403 		if (!shown_commit_line) {
1404 			putc('\n', graph->revs->diffopt.file);
1405 			graph_show_line_prefix(&graph->revs->diffopt);
1406 		}
1407 		strbuf_setlen(&msgbuf, 0);
1408 	}
1409 
1410 	strbuf_release(&msgbuf);
1411 }
1412 
1413 void graph_show_oneline(struct git_graph *graph)
1414 {
1415 	struct strbuf msgbuf = STRBUF_INIT;
1416 
1417 	graph_show_line_prefix(default_diffopt);
1418 
1419 	if (!graph)
1420 		return;
1421 
1422 	graph_next_line(graph, &msgbuf);
1423 	fwrite(msgbuf.buf, sizeof(char), msgbuf.len, graph->revs->diffopt.file);
1424 	strbuf_release(&msgbuf);
1425 }
1426 
1427 void graph_show_padding(struct git_graph *graph)
1428 {
1429 	struct strbuf msgbuf = STRBUF_INIT;
1430 
1431 	graph_show_line_prefix(default_diffopt);
1432 
1433 	if (!graph)
1434 		return;
1435 
1436 	graph_padding_line(graph, &msgbuf);
1437 	fwrite(msgbuf.buf, sizeof(char), msgbuf.len, graph->revs->diffopt.file);
1438 	strbuf_release(&msgbuf);
1439 }
1440 
1441 int graph_show_remainder(struct git_graph *graph)
1442 {
1443 	struct strbuf msgbuf = STRBUF_INIT;
1444 	int shown = 0;
1445 
1446 	graph_show_line_prefix(default_diffopt);
1447 
1448 	if (!graph)
1449 		return 0;
1450 
1451 	if (graph_is_commit_finished(graph))
1452 		return 0;
1453 
1454 	for (;;) {
1455 		graph_next_line(graph, &msgbuf);
1456 		fwrite(msgbuf.buf, sizeof(char), msgbuf.len,
1457 			graph->revs->diffopt.file);
1458 		strbuf_setlen(&msgbuf, 0);
1459 		shown = 1;
1460 
1461 		if (!graph_is_commit_finished(graph)) {
1462 			putc('\n', graph->revs->diffopt.file);
1463 			graph_show_line_prefix(&graph->revs->diffopt);
1464 		} else {
1465 			break;
1466 		}
1467 	}
1468 	strbuf_release(&msgbuf);
1469 
1470 	return shown;
1471 }
1472 
1473 static void graph_show_strbuf(struct git_graph *graph,
1474 			      FILE *file,
1475 			      struct strbuf const *sb)
1476 {
1477 	char *p;
1478 
1479 	/*
1480 	 * Print the strbuf line by line,
1481 	 * and display the graph info before each line but the first.
1482 	 */
1483 	p = sb->buf;
1484 	while (p) {
1485 		size_t len;
1486 		char *next_p = strchr(p, '\n');
1487 		if (next_p) {
1488 			next_p++;
1489 			len = next_p - p;
1490 		} else {
1491 			len = (sb->buf + sb->len) - p;
1492 		}
1493 		fwrite(p, sizeof(char), len, file);
1494 		if (next_p && *next_p != '\0')
1495 			graph_show_oneline(graph);
1496 		p = next_p;
1497 	}
1498 }
1499 
1500 void graph_show_commit_msg(struct git_graph *graph,
1501 			   FILE *file,
1502 			   struct strbuf const *sb)
1503 {
1504 	int newline_terminated;
1505 
1506 	/*
1507 	 * Show the commit message
1508 	 */
1509 	graph_show_strbuf(graph, file, sb);
1510 
1511 	if (!graph)
1512 		return;
1513 
1514 	newline_terminated = (sb->len && sb->buf[sb->len - 1] == '\n');
1515 
1516 	/*
1517 	 * If there is more output needed for this commit, show it now
1518 	 */
1519 	if (!graph_is_commit_finished(graph)) {
1520 		/*
1521 		 * If sb doesn't have a terminating newline, print one now,
1522 		 * so we can start the remainder of the graph output on a
1523 		 * new line.
1524 		 */
1525 		if (!newline_terminated)
1526 			putc('\n', file);
1527 
1528 		graph_show_remainder(graph);
1529 
1530 		/*
1531 		 * If sb ends with a newline, our output should too.
1532 		 */
1533 		if (newline_terminated)
1534 			putc('\n', file);
1535 	}
1536 }
1537