graph.con commit hg-to-git: add --verbose option (37a12dd)
   1#include "cache.h"
   2#include "commit.h"
   3#include "graph.h"
   4#include "diff.h"
   5#include "revision.h"
   6
   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.
  12 *
  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.
  16 *
  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 *                  | | | |
  27 *
  28 *   If there are several parallel diagonal lines, they will need to be
  29 *   replaced with horizontal lines on subsequent rows.
  30 */
  31
  32struct column {
  33        /*
  34         * The parent commit of this column.
  35         */
  36        struct commit *commit;
  37        /*
  38         * XXX: Once we add support for colors, struct column could also
  39         * contain the color of its branch line.
  40         */
  41};
  42
  43enum graph_state {
  44        GRAPH_PADDING,
  45        GRAPH_SKIP,
  46        GRAPH_PRE_COMMIT,
  47        GRAPH_COMMIT,
  48        GRAPH_POST_MERGE,
  49        GRAPH_COLLAPSING
  50};
  51
  52struct git_graph {
  53        /*
  54         * The commit currently being processed
  55         */
  56        struct commit *commit;
  57        /* The rev-info used for the current traversal */
  58        struct rev_info *revs;
  59        /*
  60         * The number of interesting parents that this commit has.
  61         *
  62         * Note that this is not the same as the actual number of parents.
  63         * This count excludes parents that won't be printed in the graph
  64         * output, as determined by graph_is_interesting().
  65         */
  66        int num_parents;
  67        /*
  68         * The width of the graph output for this commit.
  69         * All rows for this commit are padded to this width, so that
  70         * messages printed after the graph output are aligned.
  71         */
  72        int width;
  73        /*
  74         * The next expansion row to print
  75         * when state is GRAPH_PRE_COMMIT
  76         */
  77        int expansion_row;
  78        /*
  79         * The current output state.
  80         * This tells us what kind of line graph_next_line() should output.
  81         */
  82        enum graph_state state;
  83        /*
  84         * The maximum number of columns that can be stored in the columns
  85         * and new_columns arrays.  This is also half the number of entries
  86         * that can be stored in the mapping and new_mapping arrays.
  87         */
  88        int column_capacity;
  89        /*
  90         * The number of columns (also called "branch lines" in some places)
  91         */
  92        int num_columns;
  93        /*
  94         * The number of columns in the new_columns array
  95         */
  96        int num_new_columns;
  97        /*
  98         * The number of entries in the mapping array
  99         */
 100        int mapping_size;
 101        /*
 102         * The column state before we output the current commit.
 103         */
 104        struct column *columns;
 105        /*
 106         * The new column state after we output the current commit.
 107         * Only valid when state is GRAPH_COLLAPSING.
 108         */
 109        struct column *new_columns;
 110        /*
 111         * An array that tracks the current state of each
 112         * character in the output line during state GRAPH_COLLAPSING.
 113         * Each entry is -1 if this character is empty, or a non-negative
 114         * integer if the character contains a branch line.  The value of
 115         * the integer indicates the target position for this branch line.
 116         * (I.e., this array maps the current column positions to their
 117         * desired positions.)
 118         *
 119         * The maximum capacity of this array is always
 120         * sizeof(int) * 2 * column_capacity.
 121         */
 122        int *mapping;
 123        /*
 124         * A temporary array for computing the next mapping state
 125         * while we are outputting a mapping line.  This is stored as part
 126         * of the git_graph simply so we don't have to allocate a new
 127         * temporary array each time we have to output a collapsing line.
 128         */
 129        int *new_mapping;
 130};
 131
 132struct git_graph *graph_init(struct rev_info *opt)
 133{
 134        struct git_graph *graph = xmalloc(sizeof(struct git_graph));
 135        graph->commit = NULL;
 136        graph->revs = opt;
 137        graph->num_parents = 0;
 138        graph->expansion_row = 0;
 139        graph->state = GRAPH_PADDING;
 140        graph->num_columns = 0;
 141        graph->num_new_columns = 0;
 142        graph->mapping_size = 0;
 143
 144        /*
 145         * Allocate a reasonably large default number of columns
 146         * We'll automatically grow columns later if we need more room.
 147         */
 148        graph->column_capacity = 30;
 149        graph->columns = xmalloc(sizeof(struct column) *
 150                                 graph->column_capacity);
 151        graph->new_columns = xmalloc(sizeof(struct column) *
 152                                     graph->column_capacity);
 153        graph->mapping = xmalloc(sizeof(int) * 2 * graph->column_capacity);
 154        graph->new_mapping = xmalloc(sizeof(int) * 2 * graph->column_capacity);
 155
 156        return graph;
 157}
 158
 159void graph_release(struct git_graph *graph)
 160{
 161        free(graph->columns);
 162        free(graph->new_columns);
 163        free(graph->mapping);
 164        free(graph);
 165}
 166
 167static void graph_ensure_capacity(struct git_graph *graph, int num_columns)
 168{
 169        if (graph->column_capacity >= num_columns)
 170                return;
 171
 172        do {
 173                graph->column_capacity *= 2;
 174        } while (graph->column_capacity < num_columns);
 175
 176        graph->columns = xrealloc(graph->columns,
 177                                  sizeof(struct column) *
 178                                  graph->column_capacity);
 179        graph->new_columns = xrealloc(graph->new_columns,
 180                                      sizeof(struct column) *
 181                                      graph->column_capacity);
 182        graph->mapping = xrealloc(graph->mapping,
 183                                  sizeof(int) * 2 * graph->column_capacity);
 184        graph->new_mapping = xrealloc(graph->new_mapping,
 185                                      sizeof(int) * 2 * graph->column_capacity);
 186}
 187
 188/*
 189 * Returns 1 if the commit will be printed in the graph output,
 190 * and 0 otherwise.
 191 */
 192static int graph_is_interesting(struct git_graph *graph, struct commit *commit)
 193{
 194        /*
 195         * If revs->boundary is set, commits whose children have
 196         * been shown are always interesting, even if they have the
 197         * UNINTERESTING or TREESAME flags set.
 198         */
 199        if (graph->revs && graph->revs->boundary) {
 200                if (commit->object.flags & CHILD_SHOWN)
 201                        return 1;
 202        }
 203
 204        /*
 205         * Uninteresting and pruned commits won't be printed
 206         */
 207        return (commit->object.flags & (UNINTERESTING | TREESAME)) ? 0 : 1;
 208}
 209
 210static void graph_insert_into_new_columns(struct git_graph *graph,
 211                                          struct commit *commit,
 212                                          int *mapping_index)
 213{
 214        int i;
 215
 216        /*
 217         * Ignore uinteresting commits
 218         */
 219        if (!graph_is_interesting(graph, commit))
 220                return;
 221
 222        /*
 223         * If the commit is already in the new_columns list, we don't need to
 224         * add it.  Just update the mapping correctly.
 225         */
 226        for (i = 0; i < graph->num_new_columns; i++) {
 227                if (graph->new_columns[i].commit == commit) {
 228                        graph->mapping[*mapping_index] = i;
 229                        *mapping_index += 2;
 230                        return;
 231                }
 232        }
 233
 234        /*
 235         * This commit isn't already in new_columns.  Add it.
 236         */
 237        graph->new_columns[graph->num_new_columns].commit = commit;
 238        graph->mapping[*mapping_index] = graph->num_new_columns;
 239        *mapping_index += 2;
 240        graph->num_new_columns++;
 241}
 242
 243static void graph_update_width(struct git_graph *graph,
 244                               int is_commit_in_existing_columns)
 245{
 246        /*
 247         * Compute the width needed to display the graph for this commit.
 248         * This is the maximum width needed for any row.  All other rows
 249         * will be padded to this width.
 250         *
 251         * Compute the number of columns in the widest row:
 252         * Count each existing column (graph->num_columns), and each new
 253         * column added by this commit.
 254         */
 255        int max_cols = graph->num_columns + graph->num_parents;
 256
 257        /*
 258         * Even if the current commit has no parents to be printed, it
 259         * still takes up a column for itself.
 260         */
 261        if (graph->num_parents < 1)
 262                max_cols++;
 263
 264        /*
 265         * We added a column for the the current commit as part of
 266         * graph->num_parents.  If the current commit was already in
 267         * graph->columns, then we have double counted it.
 268         */
 269        if (is_commit_in_existing_columns)
 270                max_cols--;
 271
 272        /*
 273         * Each column takes up 2 spaces
 274         */
 275        graph->width = max_cols * 2;
 276}
 277
 278static void graph_update_columns(struct git_graph *graph)
 279{
 280        struct commit_list *parent;
 281        struct column *tmp_columns;
 282        int max_new_columns;
 283        int mapping_idx;
 284        int i, seen_this, is_commit_in_columns;
 285
 286        /*
 287         * Swap graph->columns with graph->new_columns
 288         * graph->columns contains the state for the previous commit,
 289         * and new_columns now contains the state for our commit.
 290         *
 291         * We'll re-use the old columns array as storage to compute the new
 292         * columns list for the commit after this one.
 293         */
 294        tmp_columns = graph->columns;
 295        graph->columns = graph->new_columns;
 296        graph->num_columns = graph->num_new_columns;
 297
 298        graph->new_columns = tmp_columns;
 299        graph->num_new_columns = 0;
 300
 301        /*
 302         * Now update new_columns and mapping with the information for the
 303         * commit after this one.
 304         *
 305         * First, make sure we have enough room.  At most, there will
 306         * be graph->num_columns + graph->num_parents columns for the next
 307         * commit.
 308         */
 309        max_new_columns = graph->num_columns + graph->num_parents;
 310        graph_ensure_capacity(graph, max_new_columns);
 311
 312        /*
 313         * Clear out graph->mapping
 314         */
 315        graph->mapping_size = 2 * max_new_columns;
 316        for (i = 0; i < graph->mapping_size; i++)
 317                graph->mapping[i] = -1;
 318
 319        /*
 320         * Populate graph->new_columns and graph->mapping
 321         *
 322         * Some of the parents of this commit may already be in
 323         * graph->columns.  If so, graph->new_columns should only contain a
 324         * single entry for each such commit.  graph->mapping should
 325         * contain information about where each current branch line is
 326         * supposed to end up after the collapsing is performed.
 327         */
 328        seen_this = 0;
 329        mapping_idx = 0;
 330        is_commit_in_columns = 1;
 331        for (i = 0; i <= graph->num_columns; i++) {
 332                struct commit *col_commit;
 333                if (i == graph->num_columns) {
 334                        if (seen_this)
 335                                break;
 336                        is_commit_in_columns = 0;
 337                        col_commit = graph->commit;
 338                } else {
 339                        col_commit = graph->columns[i].commit;
 340                }
 341
 342                if (col_commit == graph->commit) {
 343                        int old_mapping_idx = mapping_idx;
 344                        seen_this = 1;
 345                        for (parent = graph->commit->parents;
 346                             parent;
 347                             parent = parent->next) {
 348                                graph_insert_into_new_columns(graph,
 349                                                              parent->item,
 350                                                              &mapping_idx);
 351                        }
 352                        /*
 353                         * We always need to increment mapping_idx by at
 354                         * least 2, even if it has no interesting parents.
 355                         * The current commit always takes up at least 2
 356                         * spaces.
 357                         */
 358                        if (mapping_idx == old_mapping_idx)
 359                                mapping_idx += 2;
 360                } else {
 361                        graph_insert_into_new_columns(graph, col_commit,
 362                                                      &mapping_idx);
 363                }
 364        }
 365
 366        /*
 367         * Shrink mapping_size to be the minimum necessary
 368         */
 369        while (graph->mapping_size > 1 &&
 370               graph->mapping[graph->mapping_size - 1] < 0)
 371                graph->mapping_size--;
 372
 373        /*
 374         * Compute graph->width for this commit
 375         */
 376        graph_update_width(graph, is_commit_in_columns);
 377}
 378
 379void graph_update(struct git_graph *graph, struct commit *commit)
 380{
 381        struct commit_list *parent;
 382
 383        /*
 384         * Set the new commit
 385         */
 386        graph->commit = commit;
 387
 388        /*
 389         * Count how many interesting parents this commit has
 390         */
 391        graph->num_parents = 0;
 392        for (parent = commit->parents; parent; parent = parent->next) {
 393                if (graph_is_interesting(graph, parent->item))
 394                        graph->num_parents++;
 395        }
 396
 397        /*
 398         * Call graph_update_columns() to update
 399         * columns, new_columns, and mapping.
 400         */
 401        graph_update_columns(graph);
 402
 403        graph->expansion_row = 0;
 404
 405        /*
 406         * Update graph->state.
 407         *
 408         * If the previous commit didn't get to the GRAPH_PADDING state,
 409         * it never finished its output.  Goto GRAPH_SKIP, to print out
 410         * a line to indicate that portion of the graph is missing.
 411         *
 412         * Otherwise, if there are 3 or more parents, we need to print
 413         * extra rows before the commit, to expand the branch lines around
 414         * it and make room for it.
 415         *
 416         * If there are less than 3 parents, we can immediately print the
 417         * commit line.
 418         */
 419        if (graph->state != GRAPH_PADDING)
 420                graph->state = GRAPH_SKIP;
 421        else if (graph->num_parents >= 3)
 422                graph->state = GRAPH_PRE_COMMIT;
 423        else
 424                graph->state = GRAPH_COMMIT;
 425}
 426
 427static int graph_is_mapping_correct(struct git_graph *graph)
 428{
 429        int i;
 430
 431        /*
 432         * The mapping is up to date if each entry is at its target,
 433         * or is 1 greater than its target.
 434         * (If it is 1 greater than the target, '/' will be printed, so it
 435         * will look correct on the next row.)
 436         */
 437        for (i = 0; i < graph->mapping_size; i++) {
 438                int target = graph->mapping[i];
 439                if (target < 0)
 440                        continue;
 441                if (target == (i / 2))
 442                        continue;
 443                return 0;
 444        }
 445
 446        return 1;
 447}
 448
 449static void graph_pad_horizontally(struct git_graph *graph, struct strbuf *sb)
 450{
 451        /*
 452         * Add additional spaces to the end of the strbuf, so that all
 453         * lines for a particular commit have the same width.
 454         *
 455         * This way, fields printed to the right of the graph will remain
 456         * aligned for the entire commit.
 457         */
 458        int extra;
 459        if (sb->len >= graph->width)
 460                return;
 461
 462        extra = graph->width - sb->len;
 463        strbuf_addf(sb, "%*s", (int) extra, "");
 464}
 465
 466static void graph_output_padding_line(struct git_graph *graph,
 467                                      struct strbuf *sb)
 468{
 469        int i;
 470
 471        /*
 472         * We could conceivable be called with a NULL commit
 473         * if our caller has a bug, and invokes graph_next_line()
 474         * immediately after graph_init(), without first calling
 475         * graph_update().  Return without outputting anything in this
 476         * case.
 477         */
 478        if (!graph->commit)
 479                return;
 480
 481        /*
 482         * Output a padding row, that leaves all branch lines unchanged
 483         */
 484        for (i = 0; i < graph->num_new_columns; i++) {
 485                strbuf_addstr(sb, "| ");
 486        }
 487
 488        graph_pad_horizontally(graph, sb);
 489}
 490
 491static void graph_output_skip_line(struct git_graph *graph, struct strbuf *sb)
 492{
 493        /*
 494         * Output an ellipsis to indicate that a portion
 495         * of the graph is missing.
 496         */
 497        strbuf_addstr(sb, "...");
 498        graph_pad_horizontally(graph, sb);
 499
 500        if (graph->num_parents >= 3)
 501                graph->state = GRAPH_PRE_COMMIT;
 502        else
 503                graph->state = GRAPH_COMMIT;
 504}
 505
 506static void graph_output_pre_commit_line(struct git_graph *graph,
 507                                         struct strbuf *sb)
 508{
 509        int num_expansion_rows;
 510        int i, seen_this;
 511
 512        /*
 513         * This function formats a row that increases the space around a commit
 514         * with multiple parents, to make room for it.  It should only be
 515         * called when there are 3 or more parents.
 516         *
 517         * We need 2 extra rows for every parent over 2.
 518         */
 519        assert(graph->num_parents >= 3);
 520        num_expansion_rows = (graph->num_parents - 2) * 2;
 521
 522        /*
 523         * graph->expansion_row tracks the current expansion row we are on.
 524         * It should be in the range [0, num_expansion_rows - 1]
 525         */
 526        assert(0 <= graph->expansion_row &&
 527               graph->expansion_row < num_expansion_rows);
 528
 529        /*
 530         * Output the row
 531         */
 532        seen_this = 0;
 533        for (i = 0; i < graph->num_columns; i++) {
 534                struct column *col = &graph->columns[i];
 535                if (col->commit == graph->commit) {
 536                        seen_this = 1;
 537                        strbuf_addf(sb, "| %*s", graph->expansion_row, "");
 538                } else if (seen_this) {
 539                        strbuf_addstr(sb, "\\ ");
 540                } else {
 541                        strbuf_addstr(sb, "| ");
 542                }
 543        }
 544
 545        graph_pad_horizontally(graph, sb);
 546
 547        /*
 548         * Increment graph->expansion_row,
 549         * and move to state GRAPH_COMMIT if necessary
 550         */
 551        graph->expansion_row++;
 552        if (graph->expansion_row >= num_expansion_rows)
 553                graph->state = GRAPH_COMMIT;
 554}
 555
 556static void graph_output_commit_char(struct git_graph *graph, struct strbuf *sb)
 557{
 558        /*
 559         * For boundary commits, print 'o'
 560         * (We should only see boundary commits when revs->boundary is set.)
 561         */
 562        if (graph->commit->object.flags & BOUNDARY) {
 563                assert(graph->revs->boundary);
 564                strbuf_addch(sb, 'o');
 565                return;
 566        }
 567
 568        /*
 569         * If revs->left_right is set, print '<' for commits that
 570         * come from the left side, and '>' for commits from the right
 571         * side.
 572         */
 573        if (graph->revs && graph->revs->left_right) {
 574                if (graph->commit->object.flags & SYMMETRIC_LEFT)
 575                        strbuf_addch(sb, '<');
 576                else
 577                        strbuf_addch(sb, '>');
 578                return;
 579        }
 580
 581        /*
 582         * Print 'M' for merge commits
 583         *
 584         * Note that we don't check graph->num_parents to determine if the
 585         * commit is a merge, since that only tracks the number of
 586         * "interesting" parents.  We want to print 'M' for merge commits
 587         * even if they have less than 2 interesting parents.
 588         */
 589        if (graph->commit->parents != NULL &&
 590            graph->commit->parents->next != NULL) {
 591                strbuf_addch(sb, 'M');
 592                return;
 593        }
 594
 595        /*
 596         * Print '*' in all other cases
 597         */
 598        strbuf_addch(sb, '*');
 599}
 600
 601void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
 602{
 603        int seen_this = 0;
 604        int i, j;
 605
 606        /*
 607         * Output the row containing this commit
 608         * Iterate up to and including graph->num_columns,
 609         * since the current commit may not be in any of the existing
 610         * columns.  (This happens when the current commit doesn't have any
 611         * children that we have already processed.)
 612         */
 613        seen_this = 0;
 614        for (i = 0; i <= graph->num_columns; i++) {
 615                struct commit *col_commit;
 616                if (i == graph->num_columns) {
 617                        if (seen_this)
 618                                break;
 619                        col_commit = graph->commit;
 620                } else {
 621                        col_commit = graph->columns[i].commit;
 622                }
 623
 624                if (col_commit == graph->commit) {
 625                        seen_this = 1;
 626                        graph_output_commit_char(graph, sb);
 627
 628                        if (graph->num_parents < 2)
 629                                strbuf_addch(sb, ' ');
 630                        else if (graph->num_parents == 2)
 631                                strbuf_addstr(sb, "  ");
 632                        else {
 633                                int num_dashes =
 634                                        ((graph->num_parents - 2) * 2) - 1;
 635                                for (j = 0; j < num_dashes; j++)
 636                                        strbuf_addch(sb, '-');
 637                                strbuf_addstr(sb, ". ");
 638                        }
 639                } else if (seen_this && (graph->num_parents > 1)) {
 640                        strbuf_addstr(sb, "\\ ");
 641                } else {
 642                        strbuf_addstr(sb, "| ");
 643                }
 644        }
 645
 646        graph_pad_horizontally(graph, sb);
 647
 648        /*
 649         * Update graph->state
 650         */
 651        if (graph->num_parents > 1)
 652                graph->state = GRAPH_POST_MERGE;
 653        else if (graph_is_mapping_correct(graph))
 654                graph->state = GRAPH_PADDING;
 655        else
 656                graph->state = GRAPH_COLLAPSING;
 657}
 658
 659void graph_output_post_merge_line(struct git_graph *graph, struct strbuf *sb)
 660{
 661        int seen_this = 0;
 662        int i, j;
 663
 664        /*
 665         * Output the post-merge row
 666         */
 667        for (i = 0; i <= graph->num_columns; i++) {
 668                struct commit *col_commit;
 669                if (i == graph->num_columns) {
 670                        if (seen_this)
 671                                break;
 672                        col_commit = graph->commit;
 673                } else {
 674                        col_commit = graph->columns[i].commit;
 675                }
 676
 677                if (col_commit == graph->commit) {
 678                        seen_this = 1;
 679                        strbuf_addch(sb, '|');
 680                        for (j = 0; j < graph->num_parents - 1; j++)
 681                                strbuf_addstr(sb, "\\ ");
 682                        if (graph->num_parents == 2)
 683                                strbuf_addch(sb, ' ');
 684                } else if (seen_this && (graph->num_parents > 2)) {
 685                        strbuf_addstr(sb, "\\ ");
 686                } else {
 687                        strbuf_addstr(sb, "| ");
 688                }
 689        }
 690
 691        graph_pad_horizontally(graph, sb);
 692
 693        /*
 694         * Update graph->state
 695         */
 696        if (graph_is_mapping_correct(graph))
 697                graph->state = GRAPH_PADDING;
 698        else
 699                graph->state = GRAPH_COLLAPSING;
 700}
 701
 702void graph_output_collapsing_line(struct git_graph *graph, struct strbuf *sb)
 703{
 704        int i;
 705        int *tmp_mapping;
 706
 707        /*
 708         * Clear out the new_mapping array
 709         */
 710        for (i = 0; i < graph->mapping_size; i++)
 711                graph->new_mapping[i] = -1;
 712
 713        for (i = 0; i < graph->mapping_size; i++) {
 714                int target = graph->mapping[i];
 715                if (target < 0)
 716                        continue;
 717
 718                /*
 719                 * Since update_columns() always inserts the leftmost
 720                 * column first, each branch's target location should
 721                 * always be either its current location or to the left of
 722                 * its current location.
 723                 *
 724                 * We never have to move branches to the right.  This makes
 725                 * the graph much more legible, since whenever branches
 726                 * cross, only one is moving directions.
 727                 */
 728                assert(target * 2 <= i);
 729
 730                if (target * 2 == i) {
 731                        /*
 732                         * This column is already in the
 733                         * correct place
 734                         */
 735                        assert(graph->new_mapping[i] == -1);
 736                        graph->new_mapping[i] = target;
 737                } else if (graph->new_mapping[i - 1] < 0) {
 738                        /*
 739                         * Nothing is to the left.
 740                         * Move to the left by one
 741                         */
 742                        graph->new_mapping[i - 1] = target;
 743                } else if (graph->new_mapping[i - 1] == target) {
 744                        /*
 745                         * There is a branch line to our left
 746                         * already, and it is our target.  We
 747                         * combine with this line, since we share
 748                         * the same parent commit.
 749                         *
 750                         * We don't have to add anything to the
 751                         * output or new_mapping, since the
 752                         * existing branch line has already taken
 753                         * care of it.
 754                         */
 755                } else {
 756                        /*
 757                         * There is a branch line to our left,
 758                         * but it isn't our target.  We need to
 759                         * cross over it.
 760                         *
 761                         * The space just to the left of this
 762                         * branch should always be empty.
 763                         */
 764                        assert(graph->new_mapping[i - 1] > target);
 765                        assert(graph->new_mapping[i - 2] < 0);
 766                        graph->new_mapping[i - 2] = target;
 767                }
 768        }
 769
 770        /*
 771         * The new mapping may be 1 smaller than the old mapping
 772         */
 773        if (graph->new_mapping[graph->mapping_size - 1] < 0)
 774                graph->mapping_size--;
 775
 776        /*
 777         * Output out a line based on the new mapping info
 778         */
 779        for (i = 0; i < graph->mapping_size; i++) {
 780                int target = graph->new_mapping[i];
 781                if (target < 0)
 782                        strbuf_addch(sb, ' ');
 783                else if (target * 2 == i)
 784                        strbuf_addch(sb, '|');
 785                else
 786                        strbuf_addch(sb, '/');
 787        }
 788
 789        graph_pad_horizontally(graph, sb);
 790
 791        /*
 792         * Swap mapping and new_mapping
 793         */
 794        tmp_mapping = graph->mapping;
 795        graph->mapping = graph->new_mapping;
 796        graph->new_mapping = tmp_mapping;
 797
 798        /*
 799         * If graph->mapping indicates that all of the branch lines
 800         * are already in the correct positions, we are done.
 801         * Otherwise, we need to collapse some branch lines together.
 802         */
 803        if (graph_is_mapping_correct(graph))
 804                graph->state = GRAPH_PADDING;
 805}
 806
 807int graph_next_line(struct git_graph *graph, struct strbuf *sb)
 808{
 809        switch (graph->state) {
 810        case GRAPH_PADDING:
 811                graph_output_padding_line(graph, sb);
 812                return 0;
 813        case GRAPH_SKIP:
 814                graph_output_skip_line(graph, sb);
 815                return 0;
 816        case GRAPH_PRE_COMMIT:
 817                graph_output_pre_commit_line(graph, sb);
 818                return 0;
 819        case GRAPH_COMMIT:
 820                graph_output_commit_line(graph, sb);
 821                return 1;
 822        case GRAPH_POST_MERGE:
 823                graph_output_post_merge_line(graph, sb);
 824                return 0;
 825        case GRAPH_COLLAPSING:
 826                graph_output_collapsing_line(graph, sb);
 827                return 0;
 828        }
 829
 830        assert(0);
 831        return 0;
 832}
 833
 834void graph_padding_line(struct git_graph *graph, struct strbuf *sb)
 835{
 836        int i, j;
 837
 838        if (graph->state != GRAPH_COMMIT) {
 839                graph_next_line(graph, sb);
 840                return;
 841        }
 842
 843        /*
 844         * Output the row containing this commit
 845         * Iterate up to and including graph->num_columns,
 846         * since the current commit may not be in any of the existing
 847         * columns.  (This happens when the current commit doesn't have any
 848         * children that we have already processed.)
 849         */
 850        for (i = 0; i < graph->num_columns; i++) {
 851                struct commit *col_commit = graph->columns[i].commit;
 852                if (col_commit == graph->commit) {
 853                        strbuf_addch(sb, '|');
 854
 855                        if (graph->num_parents < 3)
 856                                strbuf_addch(sb, ' ');
 857                        else {
 858                                int num_spaces = ((graph->num_parents - 2) * 2);
 859                                for (j = 0; j < num_spaces; j++)
 860                                        strbuf_addch(sb, ' ');
 861                        }
 862                } else {
 863                        strbuf_addstr(sb, "| ");
 864                }
 865        }
 866
 867        graph_pad_horizontally(graph, sb);
 868}
 869
 870int graph_is_commit_finished(struct git_graph const *graph)
 871{
 872        return (graph->state == GRAPH_PADDING);
 873}
 874
 875void graph_show_commit(struct git_graph *graph)
 876{
 877        struct strbuf msgbuf;
 878        int shown_commit_line = 0;
 879
 880        if (!graph)
 881                return;
 882
 883        strbuf_init(&msgbuf, 0);
 884
 885        while (!shown_commit_line) {
 886                shown_commit_line = graph_next_line(graph, &msgbuf);
 887                fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
 888                if (!shown_commit_line)
 889                        putchar('\n');
 890                strbuf_setlen(&msgbuf, 0);
 891        }
 892
 893        strbuf_release(&msgbuf);
 894}
 895
 896void graph_show_oneline(struct git_graph *graph)
 897{
 898        struct strbuf msgbuf;
 899
 900        if (!graph)
 901                return;
 902
 903        strbuf_init(&msgbuf, 0);
 904        graph_next_line(graph, &msgbuf);
 905        fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
 906        strbuf_release(&msgbuf);
 907}
 908
 909void graph_show_padding(struct git_graph *graph)
 910{
 911        struct strbuf msgbuf;
 912
 913        if (!graph)
 914                return;
 915
 916        strbuf_init(&msgbuf, 0);
 917        graph_padding_line(graph, &msgbuf);
 918        fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
 919        strbuf_release(&msgbuf);
 920}
 921
 922int graph_show_remainder(struct git_graph *graph)
 923{
 924        struct strbuf msgbuf;
 925        int shown = 0;
 926
 927        if (!graph)
 928                return 0;
 929
 930        if (graph_is_commit_finished(graph))
 931                return 0;
 932
 933        strbuf_init(&msgbuf, 0);
 934        for (;;) {
 935                graph_next_line(graph, &msgbuf);
 936                fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
 937                strbuf_setlen(&msgbuf, 0);
 938                shown = 1;
 939
 940                if (!graph_is_commit_finished(graph))
 941                        putchar('\n');
 942                else
 943                        break;
 944        }
 945        strbuf_release(&msgbuf);
 946
 947        return shown;
 948}
 949
 950
 951void graph_show_strbuf(struct git_graph *graph, struct strbuf const *sb)
 952{
 953        char *p;
 954
 955        if (!graph) {
 956                fwrite(sb->buf, sizeof(char), sb->len, stdout);
 957                return;
 958        }
 959
 960        /*
 961         * Print the strbuf line by line,
 962         * and display the graph info before each line but the first.
 963         */
 964        p = sb->buf;
 965        while (p) {
 966                size_t len;
 967                char *next_p = strchr(p, '\n');
 968                if (next_p) {
 969                        next_p++;
 970                        len = next_p - p;
 971                } else {
 972                        len = (sb->buf + sb->len) - p;
 973                }
 974                fwrite(p, sizeof(char), len, stdout);
 975                if (next_p && *next_p != '\0')
 976                        graph_show_oneline(graph);
 977                p = next_p;
 978        }
 979}
 980
 981void graph_show_commit_msg(struct git_graph *graph,
 982                           struct strbuf const *sb)
 983{
 984        int newline_terminated;
 985
 986        if (!graph) {
 987                /*
 988                 * If there's no graph, just print the message buffer.
 989                 *
 990                 * The message buffer for CMIT_FMT_ONELINE and
 991                 * CMIT_FMT_USERFORMAT are already missing a terminating
 992                 * newline.  All of the other formats should have it.
 993                 */
 994                fwrite(sb->buf, sizeof(char), sb->len, stdout);
 995                return;
 996        }
 997
 998        newline_terminated = (sb->len && sb->buf[sb->len - 1] == '\n');
 999
1000        /*
1001         * Show the commit message
1002         */
1003        graph_show_strbuf(graph, sb);
1004
1005        /*
1006         * If there is more output needed for this commit, show it now
1007         */
1008        if (!graph_is_commit_finished(graph)) {
1009                /*
1010                 * If sb doesn't have a terminating newline, print one now,
1011                 * so we can start the remainder of the graph output on a
1012                 * new line.
1013                 */
1014                if (!newline_terminated)
1015                        putchar('\n');
1016
1017                graph_show_remainder(graph);
1018
1019                /*
1020                 * If sb ends with a newline, our output should too.
1021                 */
1022                if (newline_terminated)
1023                        putchar('\n');
1024        }
1025}