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Diffstat (limited to 'third_party/git/diffcore-break.c')
| -rw-r--r-- | third_party/git/diffcore-break.c | 305 |
1 files changed, 0 insertions, 305 deletions
diff --git a/third_party/git/diffcore-break.c b/third_party/git/diffcore-break.c deleted file mode 100644 index 875aefd3fe..0000000000 --- a/third_party/git/diffcore-break.c +++ /dev/null @@ -1,305 +0,0 @@ -/* - * Copyright (C) 2005 Junio C Hamano - */ -#include "cache.h" -#include "diff.h" -#include "diffcore.h" - -static int should_break(struct repository *r, - struct diff_filespec *src, - struct diff_filespec *dst, - int break_score, - int *merge_score_p) -{ - /* dst is recorded as a modification of src. Are they so - * different that we are better off recording this as a pair - * of delete and create? - * - * There are two criteria used in this algorithm. For the - * purposes of helping later rename/copy, we take both delete - * and insert into account and estimate the amount of "edit". - * If the edit is very large, we break this pair so that - * rename/copy can pick the pieces up to match with other - * files. - * - * On the other hand, we would want to ignore inserts for the - * pure "complete rewrite" detection. As long as most of the - * existing contents were removed from the file, it is a - * complete rewrite, and if sizable chunk from the original - * still remains in the result, it is not a rewrite. It does - * not matter how much or how little new material is added to - * the file. - * - * The score we leave for such a broken filepair uses the - * latter definition so that later clean-up stage can find the - * pieces that should not have been broken according to the - * latter definition after rename/copy runs, and merge the - * broken pair that have a score lower than given criteria - * back together. The break operation itself happens - * according to the former definition. - * - * The minimum_edit parameter tells us when to break (the - * amount of "edit" required for us to consider breaking the - * pair). We leave the amount of deletion in *merge_score_p - * when we return. - * - * The value we return is 1 if we want the pair to be broken, - * or 0 if we do not. - */ - unsigned long delta_size, max_size; - unsigned long src_copied, literal_added, src_removed; - - *merge_score_p = 0; /* assume no deletion --- "do not break" - * is the default. - */ - - if (S_ISREG(src->mode) != S_ISREG(dst->mode)) { - *merge_score_p = (int)MAX_SCORE; - return 1; /* even their types are different */ - } - - if (src->oid_valid && dst->oid_valid && - oideq(&src->oid, &dst->oid)) - return 0; /* they are the same */ - - if (diff_populate_filespec(r, src, 0) || - diff_populate_filespec(r, dst, 0)) - return 0; /* error but caught downstream */ - - max_size = ((src->size > dst->size) ? src->size : dst->size); - if (max_size < MINIMUM_BREAK_SIZE) - return 0; /* we do not break too small filepair */ - - if (!src->size) - return 0; /* we do not let empty files get renamed */ - - if (diffcore_count_changes(r, src, dst, - &src->cnt_data, &dst->cnt_data, - &src_copied, &literal_added)) - return 0; - - /* sanity */ - if (src->size < src_copied) - src_copied = src->size; - if (dst->size < literal_added + src_copied) { - if (src_copied < dst->size) - literal_added = dst->size - src_copied; - else - literal_added = 0; - } - src_removed = src->size - src_copied; - - /* Compute merge-score, which is "how much is removed - * from the source material". The clean-up stage will - * merge the surviving pair together if the score is - * less than the minimum, after rename/copy runs. - */ - *merge_score_p = (int)(src_removed * MAX_SCORE / src->size); - if (*merge_score_p > break_score) - return 1; - - /* Extent of damage, which counts both inserts and - * deletes. - */ - delta_size = src_removed + literal_added; - if (delta_size * MAX_SCORE / max_size < break_score) - return 0; - - /* If you removed a lot without adding new material, that is - * not really a rewrite. - */ - if ((src->size * break_score < src_removed * MAX_SCORE) && - (literal_added * 20 < src_removed) && - (literal_added * 20 < src_copied)) - return 0; - - return 1; -} - -void diffcore_break(struct repository *r, int break_score) -{ - struct diff_queue_struct *q = &diff_queued_diff; - struct diff_queue_struct outq; - - /* When the filepair has this much edit (insert and delete), - * it is first considered to be a rewrite and broken into a - * create and delete filepair. This is to help breaking a - * file that had too much new stuff added, possibly from - * moving contents from another file, so that rename/copy can - * match it with the other file. - * - * int break_score; we reuse incoming parameter for this. - */ - - /* After a pair is broken according to break_score and - * subjected to rename/copy, both of them may survive intact, - * due to lack of suitable rename/copy peer. Or, the caller - * may be calling us without using rename/copy. When that - * happens, we merge the broken pieces back into one - * modification together if the pair did not have more than - * this much delete. For this computation, we do not take - * insert into account at all. If you start from a 100-line - * file and delete 97 lines of it, it does not matter if you - * add 27 lines to it to make a new 30-line file or if you add - * 997 lines to it to make a 1000-line file. Either way what - * you did was a rewrite of 97%. On the other hand, if you - * delete 3 lines, keeping 97 lines intact, it does not matter - * if you add 3 lines to it to make a new 100-line file or if - * you add 903 lines to it to make a new 1000-line file. - * Either way you did a lot of additions and not a rewrite. - * This merge happens to catch the latter case. A merge_score - * of 80% would be a good default value (a broken pair that - * has score lower than merge_score will be merged back - * together). - */ - int merge_score; - int i; - - /* See comment on DEFAULT_BREAK_SCORE and - * DEFAULT_MERGE_SCORE in diffcore.h - */ - merge_score = (break_score >> 16) & 0xFFFF; - break_score = (break_score & 0xFFFF); - - if (!break_score) - break_score = DEFAULT_BREAK_SCORE; - if (!merge_score) - merge_score = DEFAULT_MERGE_SCORE; - - DIFF_QUEUE_CLEAR(&outq); - - for (i = 0; i < q->nr; i++) { - struct diff_filepair *p = q->queue[i]; - int score; - - /* - * We deal only with in-place edit of blobs. - * We do not break anything else. - */ - if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two) && - object_type(p->one->mode) == OBJ_BLOB && - object_type(p->two->mode) == OBJ_BLOB && - !strcmp(p->one->path, p->two->path)) { - if (should_break(r, p->one, p->two, - break_score, &score)) { - /* Split this into delete and create */ - struct diff_filespec *null_one, *null_two; - struct diff_filepair *dp; - - /* Set score to 0 for the pair that - * needs to be merged back together - * should they survive rename/copy. - * Also we do not want to break very - * small files. - */ - if (score < merge_score) - score = 0; - - /* deletion of one */ - null_one = alloc_filespec(p->one->path); - dp = diff_queue(&outq, p->one, null_one); - dp->score = score; - dp->broken_pair = 1; - - /* creation of two */ - null_two = alloc_filespec(p->two->path); - dp = diff_queue(&outq, null_two, p->two); - dp->score = score; - dp->broken_pair = 1; - - diff_free_filespec_blob(p->one); - diff_free_filespec_blob(p->two); - free(p); /* not diff_free_filepair(), we are - * reusing one and two here. - */ - continue; - } - } - diff_free_filespec_data(p->one); - diff_free_filespec_data(p->two); - diff_q(&outq, p); - } - free(q->queue); - *q = outq; - - return; -} - -static void merge_broken(struct diff_filepair *p, - struct diff_filepair *pp, - struct diff_queue_struct *outq) -{ - /* p and pp are broken pairs we want to merge */ - struct diff_filepair *c = p, *d = pp, *dp; - if (DIFF_FILE_VALID(p->one)) { - /* this must be a delete half */ - d = p; c = pp; - } - /* Sanity check */ - if (!DIFF_FILE_VALID(d->one)) - die("internal error in merge #1"); - if (DIFF_FILE_VALID(d->two)) - die("internal error in merge #2"); - if (DIFF_FILE_VALID(c->one)) - die("internal error in merge #3"); - if (!DIFF_FILE_VALID(c->two)) - die("internal error in merge #4"); - - dp = diff_queue(outq, d->one, c->two); - dp->score = p->score; - /* - * We will be one extra user of the same src side of the - * broken pair, if it was used as the rename source for other - * paths elsewhere. Increment to mark that the path stays - * in the resulting tree. - */ - d->one->rename_used++; - diff_free_filespec_data(d->two); - diff_free_filespec_data(c->one); - free(d); - free(c); -} - -void diffcore_merge_broken(void) -{ - struct diff_queue_struct *q = &diff_queued_diff; - struct diff_queue_struct outq; - int i, j; - - DIFF_QUEUE_CLEAR(&outq); - - for (i = 0; i < q->nr; i++) { - struct diff_filepair *p = q->queue[i]; - if (!p) - /* we already merged this with its peer */ - continue; - else if (p->broken_pair && - !strcmp(p->one->path, p->two->path)) { - /* If the peer also survived rename/copy, then - * we merge them back together. - */ - for (j = i + 1; j < q->nr; j++) { - struct diff_filepair *pp = q->queue[j]; - if (pp->broken_pair && - !strcmp(pp->one->path, pp->two->path) && - !strcmp(p->one->path, pp->two->path)) { - /* Peer survived. Merge them */ - merge_broken(p, pp, &outq); - q->queue[j] = NULL; - break; - } - } - if (q->nr <= j) - /* The peer did not survive, so we keep - * it in the output. - */ - diff_q(&outq, p); - } - else - diff_q(&outq, p); - } - free(q->queue); - *q = outq; - - return; -} |