Merge commit 'junio/next' into next
[git/platforms/storm.git] / graph.c
blob9d6ed30b0bef22bd8b56da9a12688c760b661776
1 #include "cache.h"
2 #include "commit.h"
3 #include "graph.h"
4 #include "diff.h"
5 #include "revision.h"
7 /*
8 * TODO:
9 * - Add colors to the graph.
10 * Pick a color for each column, and print all characters
11 * in that column with the specified color.
13 * - Limit the number of columns, similar to the way gitk does.
14 * If we reach more than a specified number of columns, omit
15 * sections of some columns.
17 * - The output during the GRAPH_PRE_COMMIT and GRAPH_COLLAPSING states
18 * could be made more compact by printing horizontal lines, instead of
19 * long diagonal lines. For example, during collapsing, something like
20 * this: instead of this:
21 * | | | | | | | | | |
22 * | |_|_|/ | | | |/
23 * |/| | | | | |/|
24 * | | | | | |/| |
25 * |/| | |
26 * | | | |
28 * If there are several parallel diagonal lines, they will need to be
29 * replaced with horizontal lines on subsequent rows.
32 struct column {
34 * The parent commit of this column.
36 struct commit *commit;
38 * XXX: Once we add support for colors, struct column could also
39 * contain the color of its branch line.
43 enum graph_state {
44 GRAPH_PADDING,
45 GRAPH_SKIP,
46 GRAPH_PRE_COMMIT,
47 GRAPH_COMMIT,
48 GRAPH_POST_MERGE,
49 GRAPH_COLLAPSING
52 struct git_graph {
54 * The commit currently being processed
56 struct commit *commit;
58 * The number of parents this commit has.
59 * (Stored so we don't have to walk over them each time we need
60 * this number)
62 int num_parents;
64 * The width of the graph output for this commit.
65 * All rows for this commit are padded to this width, so that
66 * messages printed after the graph output are aligned.
68 int width;
70 * The next expansion row to print
71 * when state is GRAPH_PRE_COMMIT
73 int expansion_row;
75 * The current output state.
76 * This tells us what kind of line graph_next_line() should output.
78 enum graph_state state;
80 * The maximum number of columns that can be stored in the columns
81 * and new_columns arrays. This is also half the number of entries
82 * that can be stored in the mapping and new_mapping arrays.
84 int column_capacity;
86 * The number of columns (also called "branch lines" in some places)
88 int num_columns;
90 * The number of columns in the new_columns array
92 int num_new_columns;
94 * The number of entries in the mapping array
96 int mapping_size;
98 * The column state before we output the current commit.
100 struct column *columns;
102 * The new column state after we output the current commit.
103 * Only valid when state is GRAPH_COLLAPSING.
105 struct column *new_columns;
107 * An array that tracks the current state of each
108 * character in the output line during state GRAPH_COLLAPSING.
109 * Each entry is -1 if this character is empty, or a non-negative
110 * integer if the character contains a branch line. The value of
111 * the integer indicates the target position for this branch line.
112 * (I.e., this array maps the current column positions to their
113 * desired positions.)
115 * The maximum capacity of this array is always
116 * sizeof(int) * 2 * column_capacity.
118 int *mapping;
120 * A temporary array for computing the next mapping state
121 * while we are outputting a mapping line. This is stored as part
122 * of the git_graph simply so we don't have to allocate a new
123 * temporary array each time we have to output a collapsing line.
125 int *new_mapping;
128 struct git_graph *graph_init(void)
130 struct git_graph *graph = xmalloc(sizeof(struct git_graph));
131 graph->commit = NULL;
132 graph->num_parents = 0;
133 graph->expansion_row = 0;
134 graph->state = GRAPH_PADDING;
135 graph->num_columns = 0;
136 graph->num_new_columns = 0;
137 graph->mapping_size = 0;
140 * Allocate a reasonably large default number of columns
141 * We'll automatically grow columns later if we need more room.
143 graph->column_capacity = 30;
144 graph->columns = xmalloc(sizeof(struct column) *
145 graph->column_capacity);
146 graph->new_columns = xmalloc(sizeof(struct column) *
147 graph->column_capacity);
148 graph->mapping = xmalloc(sizeof(int) * 2 * graph->column_capacity);
149 graph->new_mapping = xmalloc(sizeof(int) * 2 * graph->column_capacity);
151 return graph;
154 void graph_release(struct git_graph *graph)
156 free(graph->columns);
157 free(graph->new_columns);
158 free(graph->mapping);
159 free(graph);
162 static void graph_ensure_capacity(struct git_graph *graph, int num_columns)
164 if (graph->column_capacity >= num_columns)
165 return;
167 do {
168 graph->column_capacity *= 2;
169 } while (graph->column_capacity < num_columns);
171 graph->columns = xrealloc(graph->columns,
172 sizeof(struct column) *
173 graph->column_capacity);
174 graph->new_columns = xrealloc(graph->new_columns,
175 sizeof(struct column) *
176 graph->column_capacity);
177 graph->mapping = xrealloc(graph->mapping,
178 sizeof(int) * 2 * graph->column_capacity);
179 graph->new_mapping = xrealloc(graph->new_mapping,
180 sizeof(int) * 2 * graph->column_capacity);
183 static void graph_insert_into_new_columns(struct git_graph *graph,
184 struct commit *commit,
185 int *mapping_index)
187 int i;
190 * Ignore uinteresting and pruned commits
192 if (commit->object.flags & (UNINTERESTING | TREESAME))
193 return;
196 * If the commit is already in the new_columns list, we don't need to
197 * add it. Just update the mapping correctly.
199 for (i = 0; i < graph->num_new_columns; i++) {
200 if (graph->new_columns[i].commit == commit) {
201 graph->mapping[*mapping_index] = i;
202 *mapping_index += 2;
203 return;
208 * This commit isn't already in new_columns. Add it.
210 graph->new_columns[graph->num_new_columns].commit = commit;
211 graph->mapping[*mapping_index] = graph->num_new_columns;
212 *mapping_index += 2;
213 graph->num_new_columns++;
216 static void graph_update_width(struct git_graph *graph,
217 int is_commit_in_existing_columns)
220 * Compute the width needed to display the graph for this commit.
221 * This is the maximum width needed for any row. All other rows
222 * will be padded to this width.
224 * Compute the number of columns in the widest row:
225 * Count each existing column (graph->num_columns), and each new
226 * column added by this commit.
228 int max_cols = graph->num_columns + graph->num_parents;
231 * Even if the current commit has no parents, it still takes up a
232 * column for itself.
234 if (graph->num_parents < 1)
235 max_cols++;
238 * We added a column for the the current commit as part of
239 * graph->num_parents. If the current commit was already in
240 * graph->columns, then we have double counted it.
242 if (is_commit_in_existing_columns)
243 max_cols--;
246 * Each column takes up 2 spaces
248 graph->width = max_cols * 2;
251 static void graph_update_columns(struct git_graph *graph)
253 struct commit_list *parent;
254 struct column *tmp_columns;
255 int max_new_columns;
256 int mapping_idx;
257 int i, seen_this, is_commit_in_columns;
260 * Swap graph->columns with graph->new_columns
261 * graph->columns contains the state for the previous commit,
262 * and new_columns now contains the state for our commit.
264 * We'll re-use the old columns array as storage to compute the new
265 * columns list for the commit after this one.
267 tmp_columns = graph->columns;
268 graph->columns = graph->new_columns;
269 graph->num_columns = graph->num_new_columns;
271 graph->new_columns = tmp_columns;
272 graph->num_new_columns = 0;
275 * Now update new_columns and mapping with the information for the
276 * commit after this one.
278 * First, make sure we have enough room. At most, there will
279 * be graph->num_columns + graph->num_parents columns for the next
280 * commit.
282 max_new_columns = graph->num_columns + graph->num_parents;
283 graph_ensure_capacity(graph, max_new_columns);
286 * Clear out graph->mapping
288 graph->mapping_size = 2 * max_new_columns;
289 for (i = 0; i < graph->mapping_size; i++)
290 graph->mapping[i] = -1;
293 * Populate graph->new_columns and graph->mapping
295 * Some of the parents of this commit may already be in
296 * graph->columns. If so, graph->new_columns should only contain a
297 * single entry for each such commit. graph->mapping should
298 * contain information about where each current branch line is
299 * supposed to end up after the collapsing is performed.
301 seen_this = 0;
302 mapping_idx = 0;
303 is_commit_in_columns = 1;
304 for (i = 0; i <= graph->num_columns; i++) {
305 struct commit *col_commit;
306 if (i == graph->num_columns) {
307 if (seen_this)
308 break;
309 is_commit_in_columns = 0;
310 col_commit = graph->commit;
311 } else {
312 col_commit = graph->columns[i].commit;
315 if (col_commit == graph->commit) {
316 seen_this = 1;
317 for (parent = graph->commit->parents;
318 parent;
319 parent = parent->next) {
320 graph_insert_into_new_columns(graph,
321 parent->item,
322 &mapping_idx);
324 } else {
325 graph_insert_into_new_columns(graph, col_commit,
326 &mapping_idx);
331 * Shrink mapping_size to be the minimum necessary
333 while (graph->mapping_size > 1 &&
334 graph->mapping[graph->mapping_size - 1] < 0)
335 graph->mapping_size--;
338 * Compute graph->width for this commit
340 graph_update_width(graph, is_commit_in_columns);
343 void graph_update(struct git_graph *graph, struct commit *commit)
345 struct commit_list *parent;
348 * Set the new commit
350 graph->commit = commit;
353 * Count how many parents this commit has
355 graph->num_parents = 0;
356 for (parent = commit->parents; parent; parent = parent->next)
357 graph->num_parents++;
360 * Call graph_update_columns() to update
361 * columns, new_columns, and mapping.
363 graph_update_columns(graph);
365 graph->expansion_row = 0;
368 * Update graph->state.
370 * If the previous commit didn't get to the GRAPH_PADDING state,
371 * it never finished its output. Goto GRAPH_SKIP, to print out
372 * a line to indicate that portion of the graph is missing.
374 * Otherwise, if there are 3 or more parents, we need to print
375 * extra rows before the commit, to expand the branch lines around
376 * it and make room for it.
378 * If there are less than 3 parents, we can immediately print the
379 * commit line.
381 if (graph->state != GRAPH_PADDING)
382 graph->state = GRAPH_SKIP;
383 else if (graph->num_parents >= 3)
384 graph->state = GRAPH_PRE_COMMIT;
385 else
386 graph->state = GRAPH_COMMIT;
389 static int graph_is_mapping_correct(struct git_graph *graph)
391 int i;
394 * The mapping is up to date if each entry is at its target,
395 * or is 1 greater than its target.
396 * (If it is 1 greater than the target, '/' will be printed, so it
397 * will look correct on the next row.)
399 for (i = 0; i < graph->mapping_size; i++) {
400 int target = graph->mapping[i];
401 if (target < 0)
402 continue;
403 if (target == (i / 2))
404 continue;
405 return 0;
408 return 1;
411 static void graph_pad_horizontally(struct git_graph *graph, struct strbuf *sb)
414 * Add additional spaces to the end of the strbuf, so that all
415 * lines for a particular commit have the same width.
417 * This way, fields printed to the right of the graph will remain
418 * aligned for the entire commit.
420 int extra;
421 if (sb->len >= graph->width)
422 return;
424 extra = graph->width - sb->len;
425 strbuf_addf(sb, "%*s", (int) extra, "");
428 static void graph_output_padding_line(struct git_graph *graph,
429 struct strbuf *sb)
431 int i;
434 * We could conceivable be called with a NULL commit
435 * if our caller has a bug, and invokes graph_next_line()
436 * immediately after graph_init(), without first calling
437 * graph_update(). Return without outputting anything in this
438 * case.
440 if (!graph->commit)
441 return;
444 * Output a padding row, that leaves all branch lines unchanged
446 for (i = 0; i < graph->num_new_columns; i++) {
447 strbuf_addstr(sb, "| ");
450 graph_pad_horizontally(graph, sb);
453 static void graph_output_skip_line(struct git_graph *graph, struct strbuf *sb)
456 * Output an ellipsis to indicate that a portion
457 * of the graph is missing.
459 strbuf_addstr(sb, "...");
460 graph_pad_horizontally(graph, sb);
462 if (graph->num_parents >= 3)
463 graph->state = GRAPH_PRE_COMMIT;
464 else
465 graph->state = GRAPH_COMMIT;
468 static void graph_output_pre_commit_line(struct git_graph *graph,
469 struct strbuf *sb)
471 int num_expansion_rows;
472 int i, seen_this;
475 * This function formats a row that increases the space around a commit
476 * with multiple parents, to make room for it. It should only be
477 * called when there are 3 or more parents.
479 * We need 2 extra rows for every parent over 2.
481 assert(graph->num_parents >= 3);
482 num_expansion_rows = (graph->num_parents - 2) * 2;
485 * graph->expansion_row tracks the current expansion row we are on.
486 * It should be in the range [0, num_expansion_rows - 1]
488 assert(0 <= graph->expansion_row &&
489 graph->expansion_row < num_expansion_rows);
492 * Output the row
494 seen_this = 0;
495 for (i = 0; i < graph->num_columns; i++) {
496 struct column *col = &graph->columns[i];
497 if (col->commit == graph->commit) {
498 seen_this = 1;
499 strbuf_addf(sb, "| %*s", graph->expansion_row, "");
500 } else if (seen_this) {
501 strbuf_addstr(sb, "\\ ");
502 } else {
503 strbuf_addstr(sb, "| ");
507 graph_pad_horizontally(graph, sb);
510 * Increment graph->expansion_row,
511 * and move to state GRAPH_COMMIT if necessary
513 graph->expansion_row++;
514 if (graph->expansion_row >= num_expansion_rows)
515 graph->state = GRAPH_COMMIT;
518 void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
520 int seen_this = 0;
521 int i, j;
524 * Output the row containing this commit
525 * Iterate up to and including graph->num_columns,
526 * since the current commit may not be in any of the existing
527 * columns. (This happens when the current commit doesn't have any
528 * children that we have already processed.)
530 seen_this = 0;
531 for (i = 0; i <= graph->num_columns; i++) {
532 struct commit *col_commit;
533 if (i == graph->num_columns) {
534 if (seen_this)
535 break;
536 col_commit = graph->commit;
537 } else {
538 col_commit = graph->columns[i].commit;
541 if (col_commit == graph->commit) {
542 seen_this = 1;
543 if (graph->num_parents > 1)
544 strbuf_addch(sb, 'M');
545 else
546 strbuf_addch(sb, '*');
548 if (graph->num_parents < 2)
549 strbuf_addch(sb, ' ');
550 else if (graph->num_parents == 2)
551 strbuf_addstr(sb, " ");
552 else {
553 int num_dashes =
554 ((graph->num_parents - 2) * 2) - 1;
555 for (j = 0; j < num_dashes; j++)
556 strbuf_addch(sb, '-');
557 strbuf_addstr(sb, ". ");
559 } else if (seen_this && (graph->num_parents > 1)) {
560 strbuf_addstr(sb, "\\ ");
561 } else {
562 strbuf_addstr(sb, "| ");
566 graph_pad_horizontally(graph, sb);
569 * Update graph->state
571 if (graph->num_parents > 1)
572 graph->state = GRAPH_POST_MERGE;
573 else if (graph_is_mapping_correct(graph))
574 graph->state = GRAPH_PADDING;
575 else
576 graph->state = GRAPH_COLLAPSING;
579 void graph_output_post_merge_line(struct git_graph *graph, struct strbuf *sb)
581 int seen_this = 0;
582 int i, j;
585 * Output the post-merge row
587 for (i = 0; i <= graph->num_columns; i++) {
588 struct commit *col_commit;
589 if (i == graph->num_columns) {
590 if (seen_this)
591 break;
592 col_commit = graph->commit;
593 } else {
594 col_commit = graph->columns[i].commit;
597 if (col_commit == graph->commit) {
598 seen_this = 1;
599 strbuf_addch(sb, '|');
600 for (j = 0; j < graph->num_parents - 1; j++)
601 strbuf_addstr(sb, "\\ ");
602 if (graph->num_parents == 2)
603 strbuf_addch(sb, ' ');
604 } else if (seen_this && (graph->num_parents > 2)) {
605 strbuf_addstr(sb, "\\ ");
606 } else {
607 strbuf_addstr(sb, "| ");
611 graph_pad_horizontally(graph, sb);
614 * Update graph->state
616 if (graph_is_mapping_correct(graph))
617 graph->state = GRAPH_PADDING;
618 else
619 graph->state = GRAPH_COLLAPSING;
622 void graph_output_collapsing_line(struct git_graph *graph, struct strbuf *sb)
624 int i;
625 int *tmp_mapping;
628 * Clear out the new_mapping array
630 for (i = 0; i < graph->mapping_size; i++)
631 graph->new_mapping[i] = -1;
633 for (i = 0; i < graph->mapping_size; i++) {
634 int target = graph->mapping[i];
635 if (target < 0)
636 continue;
639 * Since update_columns() always inserts the leftmost
640 * column first, each branch's target location should
641 * always be either its current location or to the left of
642 * its current location.
644 * We never have to move branches to the right. This makes
645 * the graph much more legible, since whenever branches
646 * cross, only one is moving directions.
648 assert(target * 2 <= i);
650 if (target * 2 == i) {
652 * This column is already in the
653 * correct place
655 assert(graph->new_mapping[i] == -1);
656 graph->new_mapping[i] = target;
657 } else if (graph->new_mapping[i - 1] < 0) {
659 * Nothing is to the left.
660 * Move to the left by one
662 graph->new_mapping[i - 1] = target;
663 } else if (graph->new_mapping[i - 1] == target) {
665 * There is a branch line to our left
666 * already, and it is our target. We
667 * combine with this line, since we share
668 * the same parent commit.
670 * We don't have to add anything to the
671 * output or new_mapping, since the
672 * existing branch line has already taken
673 * care of it.
675 } else {
677 * There is a branch line to our left,
678 * but it isn't our target. We need to
679 * cross over it.
681 * The space just to the left of this
682 * branch should always be empty.
684 assert(graph->new_mapping[i - 1] > target);
685 assert(graph->new_mapping[i - 2] < 0);
686 graph->new_mapping[i - 2] = target;
691 * The new mapping may be 1 smaller than the old mapping
693 if (graph->new_mapping[graph->mapping_size - 1] < 0)
694 graph->mapping_size--;
697 * Output out a line based on the new mapping info
699 for (i = 0; i < graph->mapping_size; i++) {
700 int target = graph->new_mapping[i];
701 if (target < 0)
702 strbuf_addch(sb, ' ');
703 else if (target * 2 == i)
704 strbuf_addch(sb, '|');
705 else
706 strbuf_addch(sb, '/');
709 graph_pad_horizontally(graph, sb);
712 * Swap mapping and new_mapping
714 tmp_mapping = graph->mapping;
715 graph->mapping = graph->new_mapping;
716 graph->new_mapping = tmp_mapping;
719 * If graph->mapping indicates that all of the branch lines
720 * are already in the correct positions, we are done.
721 * Otherwise, we need to collapse some branch lines together.
723 if (graph_is_mapping_correct(graph))
724 graph->state = GRAPH_PADDING;
727 int graph_next_line(struct git_graph *graph, struct strbuf *sb)
729 switch (graph->state) {
730 case GRAPH_PADDING:
731 graph_output_padding_line(graph, sb);
732 return 0;
733 case GRAPH_SKIP:
734 graph_output_skip_line(graph, sb);
735 return 0;
736 case GRAPH_PRE_COMMIT:
737 graph_output_pre_commit_line(graph, sb);
738 return 0;
739 case GRAPH_COMMIT:
740 graph_output_commit_line(graph, sb);
741 return 1;
742 case GRAPH_POST_MERGE:
743 graph_output_post_merge_line(graph, sb);
744 return 0;
745 case GRAPH_COLLAPSING:
746 graph_output_collapsing_line(graph, sb);
747 return 0;
750 assert(0);
751 return 0;
754 void graph_padding_line(struct git_graph *graph, struct strbuf *sb)
756 int i, j;
758 if (graph->state != GRAPH_COMMIT) {
759 graph_next_line(graph, sb);
760 return;
764 * Output the row containing this commit
765 * Iterate up to and including graph->num_columns,
766 * since the current commit may not be in any of the existing
767 * columns. (This happens when the current commit doesn't have any
768 * children that we have already processed.)
770 for (i = 0; i < graph->num_columns; i++) {
771 struct commit *col_commit = graph->columns[i].commit;
772 if (col_commit == graph->commit) {
773 strbuf_addch(sb, '|');
775 if (graph->num_parents < 3)
776 strbuf_addch(sb, ' ');
777 else {
778 int num_spaces = ((graph->num_parents - 2) * 2);
779 for (j = 0; j < num_spaces; j++)
780 strbuf_addch(sb, ' ');
782 } else {
783 strbuf_addstr(sb, "| ");
787 graph_pad_horizontally(graph, sb);
790 int graph_is_commit_finished(struct git_graph const *graph)
792 return (graph->state == GRAPH_PADDING);
795 void graph_show_commit(struct git_graph *graph)
797 struct strbuf msgbuf;
798 int shown_commit_line = 0;
800 if (!graph)
801 return;
803 strbuf_init(&msgbuf, 0);
805 while (!shown_commit_line) {
806 shown_commit_line = graph_next_line(graph, &msgbuf);
807 fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
808 if (!shown_commit_line)
809 putchar('\n');
810 strbuf_setlen(&msgbuf, 0);
813 strbuf_release(&msgbuf);
816 void graph_show_oneline(struct git_graph *graph)
818 struct strbuf msgbuf;
820 if (!graph)
821 return;
823 strbuf_init(&msgbuf, 0);
824 graph_next_line(graph, &msgbuf);
825 fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
826 strbuf_release(&msgbuf);
829 void graph_show_padding(struct git_graph *graph)
831 struct strbuf msgbuf;
833 if (!graph)
834 return;
836 strbuf_init(&msgbuf, 0);
837 graph_padding_line(graph, &msgbuf);
838 fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
839 strbuf_release(&msgbuf);
842 int graph_show_remainder(struct git_graph *graph)
844 struct strbuf msgbuf;
845 int shown = 0;
847 if (!graph)
848 return 0;
850 if (graph_is_commit_finished(graph))
851 return 0;
853 strbuf_init(&msgbuf, 0);
854 for (;;) {
855 graph_next_line(graph, &msgbuf);
856 fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
857 strbuf_setlen(&msgbuf, 0);
858 shown = 1;
860 if (!graph_is_commit_finished(graph))
861 putchar('\n');
862 else
863 break;
865 strbuf_release(&msgbuf);
867 return shown;
871 void graph_show_strbuf(struct git_graph *graph, struct strbuf const *sb)
873 char *p;
875 if (!graph) {
876 fwrite(sb->buf, sizeof(char), sb->len, stdout);
877 return;
881 * Print the strbuf line by line,
882 * and display the graph info before each line but the first.
884 p = sb->buf;
885 while (p) {
886 size_t len;
887 char *next_p = strchr(p, '\n');
888 if (next_p) {
889 next_p++;
890 len = next_p - p;
891 } else {
892 len = (sb->buf + sb->len) - p;
894 fwrite(p, sizeof(char), len, stdout);
895 if (next_p && *next_p != '\0')
896 graph_show_oneline(graph);
897 p = next_p;
901 void graph_show_commit_msg(struct git_graph *graph,
902 struct strbuf const *sb)
904 int newline_terminated;
906 if (!graph) {
908 * If there's no graph, just print the message buffer.
910 * The message buffer for CMIT_FMT_ONELINE and
911 * CMIT_FMT_USERFORMAT are already missing a terminating
912 * newline. All of the other formats should have it.
914 fwrite(sb->buf, sizeof(char), sb->len, stdout);
915 return;
918 newline_terminated = (sb->len && sb->buf[sb->len - 1] == '\n');
921 * Show the commit message
923 graph_show_strbuf(graph, sb);
926 * If there is more output needed for this commit, show it now
928 if (!graph_is_commit_finished(graph)) {
930 * If sb doesn't have a terminating newline, print one now,
931 * so we can start the remainder of the graph output on a
932 * new line.
934 if (!newline_terminated)
935 putchar('\n');
937 graph_show_remainder(graph);
940 * If sb ends with a newline, our output should too.
942 if (newline_terminated)
943 putchar('\n');