color: delay auto-color decision until point of use
[git/git.git] / graph.c
CommitLineData
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1#include "cache.h"
2#include "commit.h"
427fc5b8 3#include "color.h"
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4#include "graph.h"
5#include "diff.h"
6#include "revision.h"
7
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8/* Internal API */
9
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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 */
17static 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 *
3ea3c215 27 * Since the first line will not include the graph output, the caller is
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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 */
32static void graph_show_strbuf(struct git_graph *graph, struct strbuf const *sb);
33
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34/*
35 * TODO:
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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.
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39 */
40
41struct column {
42 /*
43 * The parent commit of this column.
44 */
45 struct commit *commit;
46 /*
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47 * The color to (optionally) print this column in. This is an
48 * index into column_colors.
c12172d2 49 */
427fc5b8 50 unsigned short color;
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51};
52
53enum graph_state {
54 GRAPH_PADDING,
55 GRAPH_SKIP,
56 GRAPH_PRE_COMMIT,
57 GRAPH_COMMIT,
58 GRAPH_POST_MERGE,
59 GRAPH_COLLAPSING
60};
61
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62static const char **column_colors;
63static unsigned short column_colors_max;
64
65void graph_set_column_colors(const char **colors, unsigned short colors_max)
66{
67 column_colors = colors;
68 column_colors_max = colors_max;
69}
70
71static const char *column_get_color_code(unsigned short color)
427fc5b8 72{
1e3d4119 73 return column_colors[color];
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74}
75
76static void strbuf_write_column(struct strbuf *sb, const struct column *c,
77 char col_char)
78{
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79 if (c->color < column_colors_max)
80 strbuf_addstr(sb, column_get_color_code(c->color));
427fc5b8 81 strbuf_addch(sb, col_char);
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82 if (c->color < column_colors_max)
83 strbuf_addstr(sb, column_get_color_code(column_colors_max));
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84}
85
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86struct git_graph {
87 /*
88 * The commit currently being processed
89 */
90 struct commit *commit;
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91 /* The rev-info used for the current traversal */
92 struct rev_info *revs;
c12172d2 93 /*
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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().
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99 */
100 int num_parents;
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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;
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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;
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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;
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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;
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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;
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190};
191
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192static 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(graph);
198
199 strbuf_reset(&msgbuf);
200 graph_padding_line(graph, &msgbuf);
201 return &msgbuf;
202}
203
7528f27d 204struct git_graph *graph_init(struct rev_info *opt)
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205{
206 struct git_graph *graph = xmalloc(sizeof(struct git_graph));
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207
208 if (!column_colors)
209 graph_set_column_colors(column_colors_ansi,
7cd52b5b 210 column_colors_ansi_max);
1e3d4119 211
c12172d2 212 graph->commit = NULL;
7528f27d 213 graph->revs = opt;
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214 graph->num_parents = 0;
215 graph->expansion_row = 0;
216 graph->state = GRAPH_PADDING;
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217 graph->prev_state = GRAPH_PADDING;
218 graph->commit_index = 0;
219 graph->prev_commit_index = 0;
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220 graph->num_columns = 0;
221 graph->num_new_columns = 0;
222 graph->mapping_size = 0;
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223 /*
224 * Start the column color at the maximum value, since we'll
225 * always increment it for the first commit we output.
226 * This way we start at 0 for the first commit.
227 */
1e3d4119 228 graph->default_column_color = column_colors_max - 1;
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229
230 /*
231 * Allocate a reasonably large default number of columns
232 * We'll automatically grow columns later if we need more room.
233 */
234 graph->column_capacity = 30;
235 graph->columns = xmalloc(sizeof(struct column) *
236 graph->column_capacity);
237 graph->new_columns = xmalloc(sizeof(struct column) *
238 graph->column_capacity);
239 graph->mapping = xmalloc(sizeof(int) * 2 * graph->column_capacity);
240 graph->new_mapping = xmalloc(sizeof(int) * 2 * graph->column_capacity);
241
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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
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249 return graph;
250}
251
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252static void graph_update_state(struct git_graph *graph, enum graph_state s)
253{
254 graph->prev_state = graph->state;
255 graph->state = s;
256}
257
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258static void graph_ensure_capacity(struct git_graph *graph, int num_columns)
259{
260 if (graph->column_capacity >= num_columns)
261 return;
262
263 do {
264 graph->column_capacity *= 2;
265 } while (graph->column_capacity < num_columns);
266
267 graph->columns = xrealloc(graph->columns,
268 sizeof(struct column) *
269 graph->column_capacity);
270 graph->new_columns = xrealloc(graph->new_columns,
271 sizeof(struct column) *
272 graph->column_capacity);
273 graph->mapping = xrealloc(graph->mapping,
274 sizeof(int) * 2 * graph->column_capacity);
275 graph->new_mapping = xrealloc(graph->new_mapping,
276 sizeof(int) * 2 * graph->column_capacity);
277}
278
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279/*
280 * Returns 1 if the commit will be printed in the graph output,
281 * and 0 otherwise.
282 */
3c68d67b 283static int graph_is_interesting(struct git_graph *graph, struct commit *commit)
37a75abc 284{
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285 /*
286 * If revs->boundary is set, commits whose children have
287 * been shown are always interesting, even if they have the
288 * UNINTERESTING or TREESAME flags set.
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289 */
290 if (graph->revs && graph->revs->boundary) {
4603ec0f 291 if (commit->object.flags & CHILD_SHOWN)
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292 return 1;
293 }
294
37a75abc 295 /*
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296 * Otherwise, use get_commit_action() to see if this commit is
297 * interesting
37a75abc 298 */
beb5af43 299 return get_commit_action(graph->revs, commit) == commit_show;
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300}
301
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302static struct commit_list *next_interesting_parent(struct git_graph *graph,
303 struct commit_list *orig)
304{
305 struct commit_list *list;
306
307 /*
308 * If revs->first_parent_only is set, only the first
309 * parent is interesting. None of the others are.
310 */
311 if (graph->revs->first_parent_only)
312 return NULL;
313
314 /*
315 * Return the next interesting commit after orig
316 */
317 for (list = orig->next; list; list = list->next) {
318 if (graph_is_interesting(graph, list->item))
319 return list;
320 }
321
322 return NULL;
323}
324
325static struct commit_list *first_interesting_parent(struct git_graph *graph)
326{
327 struct commit_list *parents = graph->commit->parents;
328
329 /*
330 * If this commit has no parents, ignore it
331 */
332 if (!parents)
333 return NULL;
334
335 /*
336 * If the first parent is interesting, return it
337 */
338 if (graph_is_interesting(graph, parents->item))
339 return parents;
340
341 /*
342 * Otherwise, call next_interesting_parent() to get
343 * the next interesting parent
344 */
345 return next_interesting_parent(graph, parents);
346}
347
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348static unsigned short graph_get_current_column_color(const struct git_graph *graph)
349{
daa0c3d9 350 if (!want_color(graph->revs->diffopt.use_color))
1e3d4119 351 return column_colors_max;
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352 return graph->default_column_color;
353}
354
355/*
356 * Update the graph's default column color.
357 */
358static void graph_increment_column_color(struct git_graph *graph)
359{
360 graph->default_column_color = (graph->default_column_color + 1) %
1e3d4119 361 column_colors_max;
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362}
363
364static unsigned short graph_find_commit_color(const struct git_graph *graph,
365 const struct commit *commit)
366{
367 int i;
368 for (i = 0; i < graph->num_columns; i++) {
369 if (graph->columns[i].commit == commit)
370 return graph->columns[i].color;
371 }
372 return graph_get_current_column_color(graph);
373}
374
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375static void graph_insert_into_new_columns(struct git_graph *graph,
376 struct commit *commit,
377 int *mapping_index)
378{
379 int i;
380
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381 /*
382 * If the commit is already in the new_columns list, we don't need to
383 * add it. Just update the mapping correctly.
384 */
385 for (i = 0; i < graph->num_new_columns; i++) {
386 if (graph->new_columns[i].commit == commit) {
387 graph->mapping[*mapping_index] = i;
388 *mapping_index += 2;
389 return;
390 }
391 }
392
393 /*
394 * This commit isn't already in new_columns. Add it.
395 */
396 graph->new_columns[graph->num_new_columns].commit = commit;
427fc5b8 397 graph->new_columns[graph->num_new_columns].color = graph_find_commit_color(graph, commit);
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398 graph->mapping[*mapping_index] = graph->num_new_columns;
399 *mapping_index += 2;
400 graph->num_new_columns++;
401}
402
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403static void graph_update_width(struct git_graph *graph,
404 int is_commit_in_existing_columns)
405{
406 /*
407 * Compute the width needed to display the graph for this commit.
408 * This is the maximum width needed for any row. All other rows
409 * will be padded to this width.
410 *
411 * Compute the number of columns in the widest row:
412 * Count each existing column (graph->num_columns), and each new
413 * column added by this commit.
414 */
415 int max_cols = graph->num_columns + graph->num_parents;
416
417 /*
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418 * Even if the current commit has no parents to be printed, it
419 * still takes up a column for itself.
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420 */
421 if (graph->num_parents < 1)
422 max_cols++;
423
424 /*
22e5e58a 425 * We added a column for the current commit as part of
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426 * graph->num_parents. If the current commit was already in
427 * graph->columns, then we have double counted it.
428 */
429 if (is_commit_in_existing_columns)
430 max_cols--;
431
432 /*
433 * Each column takes up 2 spaces
434 */
435 graph->width = max_cols * 2;
436}
437
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438static void graph_update_columns(struct git_graph *graph)
439{
440 struct commit_list *parent;
441 struct column *tmp_columns;
442 int max_new_columns;
443 int mapping_idx;
0724cb86 444 int i, seen_this, is_commit_in_columns;
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445
446 /*
447 * Swap graph->columns with graph->new_columns
448 * graph->columns contains the state for the previous commit,
449 * and new_columns now contains the state for our commit.
450 *
451 * We'll re-use the old columns array as storage to compute the new
452 * columns list for the commit after this one.
453 */
454 tmp_columns = graph->columns;
455 graph->columns = graph->new_columns;
456 graph->num_columns = graph->num_new_columns;
457
458 graph->new_columns = tmp_columns;
459 graph->num_new_columns = 0;
460
461 /*
462 * Now update new_columns and mapping with the information for the
463 * commit after this one.
464 *
465 * First, make sure we have enough room. At most, there will
466 * be graph->num_columns + graph->num_parents columns for the next
467 * commit.
468 */
469 max_new_columns = graph->num_columns + graph->num_parents;
470 graph_ensure_capacity(graph, max_new_columns);
471
472 /*
473 * Clear out graph->mapping
474 */
475 graph->mapping_size = 2 * max_new_columns;
476 for (i = 0; i < graph->mapping_size; i++)
477 graph->mapping[i] = -1;
478
479 /*
480 * Populate graph->new_columns and graph->mapping
481 *
482 * Some of the parents of this commit may already be in
483 * graph->columns. If so, graph->new_columns should only contain a
484 * single entry for each such commit. graph->mapping should
485 * contain information about where each current branch line is
486 * supposed to end up after the collapsing is performed.
487 */
488 seen_this = 0;
489 mapping_idx = 0;
0724cb86 490 is_commit_in_columns = 1;
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491 for (i = 0; i <= graph->num_columns; i++) {
492 struct commit *col_commit;
493 if (i == graph->num_columns) {
494 if (seen_this)
495 break;
0724cb86 496 is_commit_in_columns = 0;
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497 col_commit = graph->commit;
498 } else {
499 col_commit = graph->columns[i].commit;
500 }
501
502 if (col_commit == graph->commit) {
37a75abc 503 int old_mapping_idx = mapping_idx;
c12172d2 504 seen_this = 1;
3395908e 505 graph->commit_index = i;
a0ebe573 506 for (parent = first_interesting_parent(graph);
c12172d2 507 parent;
a0ebe573 508 parent = next_interesting_parent(graph, parent)) {
427fc5b8 509 /*
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510 * If this is a merge, or the start of a new
511 * childless column, increment the current
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512 * color.
513 */
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514 if (graph->num_parents > 1 ||
515 !is_commit_in_columns) {
427fc5b8 516 graph_increment_column_color(graph);
91e50b2c 517 }
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518 graph_insert_into_new_columns(graph,
519 parent->item,
520 &mapping_idx);
521 }
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522 /*
523 * We always need to increment mapping_idx by at
524 * least 2, even if it has no interesting parents.
525 * The current commit always takes up at least 2
526 * spaces.
527 */
528 if (mapping_idx == old_mapping_idx)
529 mapping_idx += 2;
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530 } else {
531 graph_insert_into_new_columns(graph, col_commit,
532 &mapping_idx);
533 }
534 }
535
536 /*
537 * Shrink mapping_size to be the minimum necessary
538 */
539 while (graph->mapping_size > 1 &&
540 graph->mapping[graph->mapping_size - 1] < 0)
541 graph->mapping_size--;
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542
543 /*
544 * Compute graph->width for this commit
545 */
546 graph_update_width(graph, is_commit_in_columns);
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547}
548
549void graph_update(struct git_graph *graph, struct commit *commit)
550{
551 struct commit_list *parent;
552
553 /*
554 * Set the new commit
555 */
556 graph->commit = commit;
557
558 /*
37a75abc 559 * Count how many interesting parents this commit has
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560 */
561 graph->num_parents = 0;
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562 for (parent = first_interesting_parent(graph);
563 parent;
564 parent = next_interesting_parent(graph, parent))
565 {
566 graph->num_parents++;
37a75abc 567 }
c12172d2 568
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569 /*
570 * Store the old commit_index in prev_commit_index.
571 * graph_update_columns() will update graph->commit_index for this
572 * commit.
573 */
574 graph->prev_commit_index = graph->commit_index;
575
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576 /*
577 * Call graph_update_columns() to update
578 * columns, new_columns, and mapping.
579 */
580 graph_update_columns(graph);
581
582 graph->expansion_row = 0;
583
584 /*
585 * Update graph->state.
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586 * Note that we don't call graph_update_state() here, since
587 * we don't want to update graph->prev_state. No line for
588 * graph->state was ever printed.
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589 *
590 * If the previous commit didn't get to the GRAPH_PADDING state,
591 * it never finished its output. Goto GRAPH_SKIP, to print out
592 * a line to indicate that portion of the graph is missing.
593 *
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594 * If there are 3 or more parents, we may need to print extra rows
595 * before the commit, to expand the branch lines around it and make
596 * room for it. We need to do this only if there is a branch row
597 * (or more) to the right of this commit.
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598 *
599 * If there are less than 3 parents, we can immediately print the
600 * commit line.
601 */
602 if (graph->state != GRAPH_PADDING)
603 graph->state = GRAPH_SKIP;
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604 else if (graph->num_parents >= 3 &&
605 graph->commit_index < (graph->num_columns - 1))
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606 graph->state = GRAPH_PRE_COMMIT;
607 else
608 graph->state = GRAPH_COMMIT;
609}
610
611static int graph_is_mapping_correct(struct git_graph *graph)
612{
613 int i;
614
615 /*
616 * The mapping is up to date if each entry is at its target,
617 * or is 1 greater than its target.
618 * (If it is 1 greater than the target, '/' will be printed, so it
619 * will look correct on the next row.)
620 */
621 for (i = 0; i < graph->mapping_size; i++) {
622 int target = graph->mapping[i];
623 if (target < 0)
624 continue;
625 if (target == (i / 2))
626 continue;
627 return 0;
628 }
629
630 return 1;
631}
632
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633static void graph_pad_horizontally(struct git_graph *graph, struct strbuf *sb,
634 int chars_written)
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635{
636 /*
637 * Add additional spaces to the end of the strbuf, so that all
638 * lines for a particular commit have the same width.
639 *
640 * This way, fields printed to the right of the graph will remain
641 * aligned for the entire commit.
c12172d2 642 */
0724cb86 643 int extra;
427fc5b8 644 if (chars_written >= graph->width)
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645 return;
646
427fc5b8 647 extra = graph->width - chars_written;
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648 strbuf_addf(sb, "%*s", (int) extra, "");
649}
650
651static void graph_output_padding_line(struct git_graph *graph,
652 struct strbuf *sb)
653{
654 int i;
655
656 /*
657 * We could conceivable be called with a NULL commit
658 * if our caller has a bug, and invokes graph_next_line()
659 * immediately after graph_init(), without first calling
660 * graph_update(). Return without outputting anything in this
661 * case.
662 */
663 if (!graph->commit)
664 return;
665
666 /*
667 * Output a padding row, that leaves all branch lines unchanged
668 */
669 for (i = 0; i < graph->num_new_columns; i++) {
427fc5b8
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670 strbuf_write_column(sb, &graph->new_columns[i], '|');
671 strbuf_addch(sb, ' ');
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672 }
673
427fc5b8 674 graph_pad_horizontally(graph, sb, graph->num_new_columns * 2);
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675}
676
677static void graph_output_skip_line(struct git_graph *graph, struct strbuf *sb)
678{
679 /*
680 * Output an ellipsis to indicate that a portion
681 * of the graph is missing.
682 */
683 strbuf_addstr(sb, "...");
427fc5b8 684 graph_pad_horizontally(graph, sb, 3);
c12172d2 685
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686 if (graph->num_parents >= 3 &&
687 graph->commit_index < (graph->num_columns - 1))
3395908e 688 graph_update_state(graph, GRAPH_PRE_COMMIT);
c12172d2 689 else
3395908e 690 graph_update_state(graph, GRAPH_COMMIT);
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AS
691}
692
693static void graph_output_pre_commit_line(struct git_graph *graph,
694 struct strbuf *sb)
695{
696 int num_expansion_rows;
697 int i, seen_this;
427fc5b8 698 int chars_written;
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699
700 /*
701 * This function formats a row that increases the space around a commit
702 * with multiple parents, to make room for it. It should only be
703 * called when there are 3 or more parents.
704 *
705 * We need 2 extra rows for every parent over 2.
706 */
707 assert(graph->num_parents >= 3);
708 num_expansion_rows = (graph->num_parents - 2) * 2;
709
710 /*
711 * graph->expansion_row tracks the current expansion row we are on.
712 * It should be in the range [0, num_expansion_rows - 1]
713 */
714 assert(0 <= graph->expansion_row &&
715 graph->expansion_row < num_expansion_rows);
716
717 /*
718 * Output the row
719 */
720 seen_this = 0;
427fc5b8 721 chars_written = 0;
c12172d2
AS
722 for (i = 0; i < graph->num_columns; i++) {
723 struct column *col = &graph->columns[i];
724 if (col->commit == graph->commit) {
725 seen_this = 1;
427fc5b8 726 strbuf_write_column(sb, col, '|');
36a31fea
AC
727 strbuf_addf(sb, "%*s", graph->expansion_row, "");
728 chars_written += 1 + graph->expansion_row;
3395908e
AS
729 } else if (seen_this && (graph->expansion_row == 0)) {
730 /*
731 * This is the first line of the pre-commit output.
732 * If the previous commit was a merge commit and
733 * ended in the GRAPH_POST_MERGE state, all branch
734 * lines after graph->prev_commit_index were
735 * printed as "\" on the previous line. Continue
736 * to print them as "\" on this line. Otherwise,
737 * print the branch lines as "|".
738 */
739 if (graph->prev_state == GRAPH_POST_MERGE &&
740 graph->prev_commit_index < i)
427fc5b8 741 strbuf_write_column(sb, col, '\\');
3395908e 742 else
427fc5b8
AC
743 strbuf_write_column(sb, col, '|');
744 chars_written++;
3395908e 745 } else if (seen_this && (graph->expansion_row > 0)) {
427fc5b8
AC
746 strbuf_write_column(sb, col, '\\');
747 chars_written++;
c12172d2 748 } else {
427fc5b8
AC
749 strbuf_write_column(sb, col, '|');
750 chars_written++;
c12172d2 751 }
427fc5b8
AC
752 strbuf_addch(sb, ' ');
753 chars_written++;
c12172d2
AS
754 }
755
427fc5b8 756 graph_pad_horizontally(graph, sb, chars_written);
c12172d2
AS
757
758 /*
759 * Increment graph->expansion_row,
760 * and move to state GRAPH_COMMIT if necessary
761 */
762 graph->expansion_row++;
763 if (graph->expansion_row >= num_expansion_rows)
3395908e 764 graph_update_state(graph, GRAPH_COMMIT);
c12172d2
AS
765}
766
3c68d67b
AS
767static void graph_output_commit_char(struct git_graph *graph, struct strbuf *sb)
768{
769 /*
770 * For boundary commits, print 'o'
771 * (We should only see boundary commits when revs->boundary is set.)
772 */
773 if (graph->commit->object.flags & BOUNDARY) {
774 assert(graph->revs->boundary);
775 strbuf_addch(sb, 'o');
776 return;
777 }
778
779 /*
1df2d656 780 * get_revision_mark() handles all other cases without assert()
3c68d67b 781 */
1df2d656 782 strbuf_addstr(sb, get_revision_mark(graph->revs, graph->commit));
3c68d67b
AS
783}
784
427fc5b8
AC
785/*
786 * Draw an octopus merge and return the number of characters written.
787 */
788static int graph_draw_octopus_merge(struct git_graph *graph,
789 struct strbuf *sb)
790{
791 /*
792 * Here dashless_commits represents the number of parents
793 * which don't need to have dashes (because their edges fit
794 * neatly under the commit).
795 */
796 const int dashless_commits = 2;
797 int col_num, i;
798 int num_dashes =
799 ((graph->num_parents - dashless_commits) * 2) - 1;
800 for (i = 0; i < num_dashes; i++) {
801 col_num = (i / 2) + dashless_commits;
802 strbuf_write_column(sb, &graph->new_columns[col_num], '-');
803 }
804 col_num = (i / 2) + dashless_commits;
805 strbuf_write_column(sb, &graph->new_columns[col_num], '.');
806 return num_dashes + 1;
807}
808
064bfbde 809static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
c12172d2
AS
810{
811 int seen_this = 0;
427fc5b8 812 int i, chars_written;
c12172d2
AS
813
814 /*
815 * Output the row containing this commit
816 * Iterate up to and including graph->num_columns,
817 * since the current commit may not be in any of the existing
818 * columns. (This happens when the current commit doesn't have any
819 * children that we have already processed.)
820 */
821 seen_this = 0;
427fc5b8 822 chars_written = 0;
c12172d2 823 for (i = 0; i <= graph->num_columns; i++) {
427fc5b8 824 struct column *col = &graph->columns[i];
c12172d2
AS
825 struct commit *col_commit;
826 if (i == graph->num_columns) {
827 if (seen_this)
828 break;
829 col_commit = graph->commit;
830 } else {
831 col_commit = graph->columns[i].commit;
832 }
833
834 if (col_commit == graph->commit) {
835 seen_this = 1;
3c68d67b 836 graph_output_commit_char(graph, sb);
427fc5b8 837 chars_written++;
c12172d2 838
a6c1a382 839 if (graph->num_parents > 2)
427fc5b8
AC
840 chars_written += graph_draw_octopus_merge(graph,
841 sb);
3395908e 842 } else if (seen_this && (graph->num_parents > 2)) {
427fc5b8
AC
843 strbuf_write_column(sb, col, '\\');
844 chars_written++;
3395908e
AS
845 } else if (seen_this && (graph->num_parents == 2)) {
846 /*
847 * This is a 2-way merge commit.
848 * There is no GRAPH_PRE_COMMIT stage for 2-way
849 * merges, so this is the first line of output
850 * for this commit. Check to see what the previous
851 * line of output was.
852 *
853 * If it was GRAPH_POST_MERGE, the branch line
854 * coming into this commit may have been '\',
855 * and not '|' or '/'. If so, output the branch
856 * line as '\' on this line, instead of '|'. This
857 * makes the output look nicer.
858 */
859 if (graph->prev_state == GRAPH_POST_MERGE &&
860 graph->prev_commit_index < i)
427fc5b8 861 strbuf_write_column(sb, col, '\\');
3395908e 862 else
427fc5b8
AC
863 strbuf_write_column(sb, col, '|');
864 chars_written++;
c12172d2 865 } else {
427fc5b8
AC
866 strbuf_write_column(sb, col, '|');
867 chars_written++;
c12172d2 868 }
427fc5b8
AC
869 strbuf_addch(sb, ' ');
870 chars_written++;
c12172d2
AS
871 }
872
427fc5b8 873 graph_pad_horizontally(graph, sb, chars_written);
c12172d2
AS
874
875 /*
876 * Update graph->state
877 */
878 if (graph->num_parents > 1)
3395908e 879 graph_update_state(graph, GRAPH_POST_MERGE);
c12172d2 880 else if (graph_is_mapping_correct(graph))
3395908e 881 graph_update_state(graph, GRAPH_PADDING);
c12172d2 882 else
3395908e 883 graph_update_state(graph, GRAPH_COLLAPSING);
c12172d2
AS
884}
885
427fc5b8
AC
886static struct column *find_new_column_by_commit(struct git_graph *graph,
887 struct commit *commit)
888{
889 int i;
890 for (i = 0; i < graph->num_new_columns; i++) {
891 if (graph->new_columns[i].commit == commit)
892 return &graph->new_columns[i];
893 }
67da52be 894 return NULL;
427fc5b8
AC
895}
896
064bfbde 897static void graph_output_post_merge_line(struct git_graph *graph, struct strbuf *sb)
c12172d2
AS
898{
899 int seen_this = 0;
427fc5b8 900 int i, j, chars_written;
c12172d2
AS
901
902 /*
903 * Output the post-merge row
904 */
427fc5b8 905 chars_written = 0;
c12172d2 906 for (i = 0; i <= graph->num_columns; i++) {
427fc5b8 907 struct column *col = &graph->columns[i];
c12172d2
AS
908 struct commit *col_commit;
909 if (i == graph->num_columns) {
910 if (seen_this)
911 break;
912 col_commit = graph->commit;
913 } else {
427fc5b8 914 col_commit = col->commit;
c12172d2
AS
915 }
916
917 if (col_commit == graph->commit) {
427fc5b8
AC
918 /*
919 * Since the current commit is a merge find
920 * the columns for the parent commits in
921 * new_columns and use those to format the
922 * edges.
923 */
924 struct commit_list *parents = NULL;
925 struct column *par_column;
c12172d2 926 seen_this = 1;
427fc5b8
AC
927 parents = first_interesting_parent(graph);
928 assert(parents);
929 par_column = find_new_column_by_commit(graph, parents->item);
930 assert(par_column);
931
932 strbuf_write_column(sb, par_column, '|');
933 chars_written++;
934 for (j = 0; j < graph->num_parents - 1; j++) {
935 parents = next_interesting_parent(graph, parents);
936 assert(parents);
937 par_column = find_new_column_by_commit(graph, parents->item);
938 assert(par_column);
939 strbuf_write_column(sb, par_column, '\\');
940 strbuf_addch(sb, ' ');
941 }
942 chars_written += j * 2;
3395908e 943 } else if (seen_this) {
427fc5b8
AC
944 strbuf_write_column(sb, col, '\\');
945 strbuf_addch(sb, ' ');
946 chars_written += 2;
c12172d2 947 } else {
427fc5b8
AC
948 strbuf_write_column(sb, col, '|');
949 strbuf_addch(sb, ' ');
950 chars_written += 2;
c12172d2
AS
951 }
952 }
953
427fc5b8 954 graph_pad_horizontally(graph, sb, chars_written);
c12172d2
AS
955
956 /*
957 * Update graph->state
958 */
959 if (graph_is_mapping_correct(graph))
3395908e 960 graph_update_state(graph, GRAPH_PADDING);
c12172d2 961 else
3395908e 962 graph_update_state(graph, GRAPH_COLLAPSING);
c12172d2
AS
963}
964
064bfbde 965static void graph_output_collapsing_line(struct git_graph *graph, struct strbuf *sb)
c12172d2
AS
966{
967 int i;
968 int *tmp_mapping;
eaf158f8
AC
969 short used_horizontal = 0;
970 int horizontal_edge = -1;
971 int horizontal_edge_target = -1;
c12172d2
AS
972
973 /*
974 * Clear out the new_mapping array
975 */
976 for (i = 0; i < graph->mapping_size; i++)
977 graph->new_mapping[i] = -1;
978
979 for (i = 0; i < graph->mapping_size; i++) {
980 int target = graph->mapping[i];
981 if (target < 0)
982 continue;
983
984 /*
985 * Since update_columns() always inserts the leftmost
986 * column first, each branch's target location should
987 * always be either its current location or to the left of
988 * its current location.
989 *
990 * We never have to move branches to the right. This makes
991 * the graph much more legible, since whenever branches
992 * cross, only one is moving directions.
993 */
994 assert(target * 2 <= i);
995
996 if (target * 2 == i) {
997 /*
998 * This column is already in the
999 * correct place
1000 */
1001 assert(graph->new_mapping[i] == -1);
1002 graph->new_mapping[i] = target;
1003 } else if (graph->new_mapping[i - 1] < 0) {
1004 /*
1005 * Nothing is to the left.
1006 * Move to the left by one
1007 */
1008 graph->new_mapping[i - 1] = target;
eaf158f8
AC
1009 /*
1010 * If there isn't already an edge moving horizontally
1011 * select this one.
1012 */
1013 if (horizontal_edge == -1) {
1014 int j;
1015 horizontal_edge = i;
1016 horizontal_edge_target = target;
1017 /*
1018 * The variable target is the index of the graph
1019 * column, and therefore target*2+3 is the
1020 * actual screen column of the first horizontal
1021 * line.
1022 */
1023 for (j = (target * 2)+3; j < (i - 2); j += 2)
1024 graph->new_mapping[j] = target;
1025 }
c12172d2
AS
1026 } else if (graph->new_mapping[i - 1] == target) {
1027 /*
1028 * There is a branch line to our left
1029 * already, and it is our target. We
1030 * combine with this line, since we share
1031 * the same parent commit.
1032 *
1033 * We don't have to add anything to the
1034 * output or new_mapping, since the
1035 * existing branch line has already taken
1036 * care of it.
1037 */
1038 } else {
1039 /*
1040 * There is a branch line to our left,
1041 * but it isn't our target. We need to
1042 * cross over it.
1043 *
1044 * The space just to the left of this
1045 * branch should always be empty.
eaf158f8
AC
1046 *
1047 * The branch to the left of that space
1048 * should be our eventual target.
c12172d2
AS
1049 */
1050 assert(graph->new_mapping[i - 1] > target);
1051 assert(graph->new_mapping[i - 2] < 0);
eaf158f8 1052 assert(graph->new_mapping[i - 3] == target);
c12172d2 1053 graph->new_mapping[i - 2] = target;
eaf158f8
AC
1054 /*
1055 * Mark this branch as the horizontal edge to
1056 * prevent any other edges from moving
1057 * horizontally.
1058 */
1059 if (horizontal_edge == -1)
1060 horizontal_edge = i;
c12172d2
AS
1061 }
1062 }
1063
1064 /*
1065 * The new mapping may be 1 smaller than the old mapping
1066 */
1067 if (graph->new_mapping[graph->mapping_size - 1] < 0)
1068 graph->mapping_size--;
1069
1070 /*
1071 * Output out a line based on the new mapping info
1072 */
1073 for (i = 0; i < graph->mapping_size; i++) {
1074 int target = graph->new_mapping[i];
1075 if (target < 0)
1076 strbuf_addch(sb, ' ');
1077 else if (target * 2 == i)
427fc5b8 1078 strbuf_write_column(sb, &graph->new_columns[target], '|');
eaf158f8
AC
1079 else if (target == horizontal_edge_target &&
1080 i != horizontal_edge - 1) {
1081 /*
1082 * Set the mappings for all but the
1083 * first segment to -1 so that they
1084 * won't continue into the next line.
1085 */
1086 if (i != (target * 2)+3)
1087 graph->new_mapping[i] = -1;
1088 used_horizontal = 1;
1089 strbuf_write_column(sb, &graph->new_columns[target], '_');
1090 } else {
1091 if (used_horizontal && i < horizontal_edge)
1092 graph->new_mapping[i] = -1;
427fc5b8 1093 strbuf_write_column(sb, &graph->new_columns[target], '/');
eaf158f8
AC
1094
1095 }
c12172d2
AS
1096 }
1097
427fc5b8 1098 graph_pad_horizontally(graph, sb, graph->mapping_size);
c12172d2
AS
1099
1100 /*
1101 * Swap mapping and new_mapping
1102 */
1103 tmp_mapping = graph->mapping;
1104 graph->mapping = graph->new_mapping;
1105 graph->new_mapping = tmp_mapping;
1106
1107 /*
1108 * If graph->mapping indicates that all of the branch lines
1109 * are already in the correct positions, we are done.
1110 * Otherwise, we need to collapse some branch lines together.
1111 */
1112 if (graph_is_mapping_correct(graph))
3395908e 1113 graph_update_state(graph, GRAPH_PADDING);
c12172d2
AS
1114}
1115
6bdc17d9 1116int graph_next_line(struct git_graph *graph, struct strbuf *sb)
c12172d2
AS
1117{
1118 switch (graph->state) {
1119 case GRAPH_PADDING:
1120 graph_output_padding_line(graph, sb);
1121 return 0;
1122 case GRAPH_SKIP:
1123 graph_output_skip_line(graph, sb);
1124 return 0;
1125 case GRAPH_PRE_COMMIT:
1126 graph_output_pre_commit_line(graph, sb);
1127 return 0;
1128 case GRAPH_COMMIT:
1129 graph_output_commit_line(graph, sb);
1130 return 1;
1131 case GRAPH_POST_MERGE:
1132 graph_output_post_merge_line(graph, sb);
1133 return 0;
1134 case GRAPH_COLLAPSING:
1135 graph_output_collapsing_line(graph, sb);
1136 return 0;
1137 }
1138
1139 assert(0);
1140 return 0;
1141}
1142
064bfbde 1143static void graph_padding_line(struct git_graph *graph, struct strbuf *sb)
c12172d2
AS
1144{
1145 int i, j;
1146
1147 if (graph->state != GRAPH_COMMIT) {
1148 graph_next_line(graph, sb);
1149 return;
1150 }
1151
1152 /*
1153 * Output the row containing this commit
1154 * Iterate up to and including graph->num_columns,
1155 * since the current commit may not be in any of the existing
1156 * columns. (This happens when the current commit doesn't have any
1157 * children that we have already processed.)
1158 */
1159 for (i = 0; i < graph->num_columns; i++) {
427fc5b8
AC
1160 struct column *col = &graph->columns[i];
1161 struct commit *col_commit = col->commit;
c12172d2 1162 if (col_commit == graph->commit) {
427fc5b8 1163 strbuf_write_column(sb, col, '|');
c12172d2
AS
1164
1165 if (graph->num_parents < 3)
1166 strbuf_addch(sb, ' ');
1167 else {
1168 int num_spaces = ((graph->num_parents - 2) * 2);
1169 for (j = 0; j < num_spaces; j++)
1170 strbuf_addch(sb, ' ');
1171 }
1172 } else {
427fc5b8
AC
1173 strbuf_write_column(sb, col, '|');
1174 strbuf_addch(sb, ' ');
c12172d2
AS
1175 }
1176 }
1177
427fc5b8 1178 graph_pad_horizontally(graph, sb, graph->num_columns);
3395908e
AS
1179
1180 /*
1181 * Update graph->prev_state since we have output a padding line
1182 */
1183 graph->prev_state = GRAPH_PADDING;
c12172d2
AS
1184}
1185
1186int graph_is_commit_finished(struct git_graph const *graph)
1187{
1188 return (graph->state == GRAPH_PADDING);
1189}
1190
1191void graph_show_commit(struct git_graph *graph)
1192{
f285a2d7 1193 struct strbuf msgbuf = STRBUF_INIT;
c12172d2
AS
1194 int shown_commit_line = 0;
1195
1196 if (!graph)
1197 return;
1198
c12172d2
AS
1199 while (!shown_commit_line) {
1200 shown_commit_line = graph_next_line(graph, &msgbuf);
1201 fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
1202 if (!shown_commit_line)
1203 putchar('\n');
1204 strbuf_setlen(&msgbuf, 0);
1205 }
1206
1207 strbuf_release(&msgbuf);
1208}
1209
1210void graph_show_oneline(struct git_graph *graph)
1211{
f285a2d7 1212 struct strbuf msgbuf = STRBUF_INIT;
c12172d2
AS
1213
1214 if (!graph)
1215 return;
1216
c12172d2
AS
1217 graph_next_line(graph, &msgbuf);
1218 fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
1219 strbuf_release(&msgbuf);
1220}
1221
1222void graph_show_padding(struct git_graph *graph)
1223{
f285a2d7 1224 struct strbuf msgbuf = STRBUF_INIT;
c12172d2
AS
1225
1226 if (!graph)
1227 return;
1228
c12172d2
AS
1229 graph_padding_line(graph, &msgbuf);
1230 fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
1231 strbuf_release(&msgbuf);
1232}
1233
1234int graph_show_remainder(struct git_graph *graph)
1235{
f285a2d7 1236 struct strbuf msgbuf = STRBUF_INIT;
c12172d2
AS
1237 int shown = 0;
1238
1239 if (!graph)
1240 return 0;
1241
1242 if (graph_is_commit_finished(graph))
1243 return 0;
1244
c12172d2
AS
1245 for (;;) {
1246 graph_next_line(graph, &msgbuf);
1247 fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
1248 strbuf_setlen(&msgbuf, 0);
1249 shown = 1;
1250
1251 if (!graph_is_commit_finished(graph))
1252 putchar('\n');
1253 else
1254 break;
1255 }
1256 strbuf_release(&msgbuf);
1257
1258 return shown;
1259}
1260
1261
064bfbde 1262static void graph_show_strbuf(struct git_graph *graph, struct strbuf const *sb)
c12172d2
AS
1263{
1264 char *p;
1265
1266 if (!graph) {
1267 fwrite(sb->buf, sizeof(char), sb->len, stdout);
1268 return;
1269 }
1270
1271 /*
1272 * Print the strbuf line by line,
1273 * and display the graph info before each line but the first.
1274 */
1275 p = sb->buf;
1276 while (p) {
1277 size_t len;
1278 char *next_p = strchr(p, '\n');
1279 if (next_p) {
1280 next_p++;
1281 len = next_p - p;
1282 } else {
1283 len = (sb->buf + sb->len) - p;
1284 }
1285 fwrite(p, sizeof(char), len, stdout);
1286 if (next_p && *next_p != '\0')
1287 graph_show_oneline(graph);
1288 p = next_p;
1289 }
1290}
1291
1292void graph_show_commit_msg(struct git_graph *graph,
1293 struct strbuf const *sb)
1294{
1295 int newline_terminated;
1296
1297 if (!graph) {
1298 /*
1299 * If there's no graph, just print the message buffer.
1300 *
1301 * The message buffer for CMIT_FMT_ONELINE and
1302 * CMIT_FMT_USERFORMAT are already missing a terminating
1303 * newline. All of the other formats should have it.
1304 */
1305 fwrite(sb->buf, sizeof(char), sb->len, stdout);
1306 return;
1307 }
1308
1309 newline_terminated = (sb->len && sb->buf[sb->len - 1] == '\n');
1310
1311 /*
1312 * Show the commit message
1313 */
1314 graph_show_strbuf(graph, sb);
1315
1316 /*
1317 * If there is more output needed for this commit, show it now
1318 */
1319 if (!graph_is_commit_finished(graph)) {
1320 /*
1321 * If sb doesn't have a terminating newline, print one now,
1322 * so we can start the remainder of the graph output on a
1323 * new line.
1324 */
1325 if (!newline_terminated)
1326 putchar('\n');
1327
1328 graph_show_remainder(graph);
1329
1330 /*
1331 * If sb ends with a newline, our output should too.
1332 */
1333 if (newline_terminated)
1334 putchar('\n');
1335 }
1336}