Mercurial > hg
view mercurial/thirdparty/xdiff/xprepare.c @ 45830:c102b704edb5
global: use python3 in shebangs
Python 3 is the future. We want Python scripts to be using Python 3
by default.
This change updates all `#!/usr/bin/env python` shebangs to use
`python3`.
Does this mean all scripts use or require Python 3: no.
In the test environment, the `PATH` environment variable in tests is
updated to guarantee that the Python executable used to run
run-tests.py is used. Since test scripts all now use
`#!/usr/bin/env python3`, we had to update this code to install
a `python3` symlink instead of `python`.
It is possible there are some random scripts now executed with the
incorrect Python interpreter in some contexts. However, I would argue
that this was a pre-existing bug: we should almost always be executing
new Python processes using the `sys.executable` from the originating
Python script, as `python` or `python3` won't guarantee we'll use the
same interpreter.
Differential Revision: https://phab.mercurial-scm.org/D9273
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Fri, 06 Nov 2020 13:58:59 -0800 |
parents | d40b9e29c114 |
children |
line wrap: on
line source
/* * LibXDiff by Davide Libenzi ( File Differential Library ) * Copyright (C) 2003 Davide Libenzi * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, see * <http://www.gnu.org/licenses/>. * * Davide Libenzi <davidel@xmailserver.org> * */ #include "xinclude.h" #define XDL_KPDIS_RUN 4 #define XDL_MAX_EQLIMIT 1024 #define XDL_SIMSCAN_WINDOW 100 #define XDL_GUESS_NLINES1 256 typedef struct s_xdlclass { struct s_xdlclass *next; uint64_t ha; char const *line; int64_t size; int64_t idx; int64_t len1, len2; } xdlclass_t; typedef struct s_xdlclassifier { unsigned int hbits; int64_t hsize; xdlclass_t **rchash; chastore_t ncha; xdlclass_t **rcrecs; int64_t alloc; int64_t count; int64_t flags; } xdlclassifier_t; static int xdl_init_classifier(xdlclassifier_t *cf, int64_t size, int64_t flags); static void xdl_free_classifier(xdlclassifier_t *cf); static int xdl_classify_record(unsigned int pass, xdlclassifier_t *cf, xrecord_t **rhash, unsigned int hbits, xrecord_t *rec); static int xdl_prepare_ctx(unsigned int pass, mmfile_t *mf, int64_t narec, xdlclassifier_t *cf, xdfile_t *xdf); static void xdl_free_ctx(xdfile_t *xdf); static int xdl_clean_mmatch(char const *dis, int64_t i, int64_t s, int64_t e); static int xdl_cleanup_records(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xdf2); static int xdl_trim_ends(xdfile_t *xdf1, xdfile_t *xdf2); static int xdl_optimize_ctxs(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xdf2); static int xdl_init_classifier(xdlclassifier_t *cf, int64_t size, int64_t flags) { cf->flags = flags; cf->hbits = xdl_hashbits(size); cf->hsize = ((uint64_t)1) << cf->hbits; if (xdl_cha_init(&cf->ncha, sizeof(xdlclass_t), size / 4 + 1) < 0) { return -1; } if (!(cf->rchash = (xdlclass_t **) xdl_malloc(cf->hsize * sizeof(xdlclass_t *)))) { xdl_cha_free(&cf->ncha); return -1; } memset(cf->rchash, 0, cf->hsize * sizeof(xdlclass_t *)); cf->alloc = size; if (!(cf->rcrecs = (xdlclass_t **) xdl_malloc(cf->alloc * sizeof(xdlclass_t *)))) { xdl_free(cf->rchash); xdl_cha_free(&cf->ncha); return -1; } cf->count = 0; return 0; } static void xdl_free_classifier(xdlclassifier_t *cf) { xdl_free(cf->rcrecs); xdl_free(cf->rchash); xdl_cha_free(&cf->ncha); } static int xdl_classify_record(unsigned int pass, xdlclassifier_t *cf, xrecord_t **rhash, unsigned int hbits, xrecord_t *rec) { int64_t hi; char const *line; xdlclass_t *rcrec; xdlclass_t **rcrecs; line = rec->ptr; hi = (long) XDL_HASHLONG(rec->ha, cf->hbits); for (rcrec = cf->rchash[hi]; rcrec; rcrec = rcrec->next) if (rcrec->ha == rec->ha && xdl_recmatch(rcrec->line, rcrec->size, rec->ptr, rec->size)) break; if (!rcrec) { if (!(rcrec = xdl_cha_alloc(&cf->ncha))) { return -1; } rcrec->idx = cf->count++; if (cf->count > cf->alloc) { cf->alloc *= 2; if (!(rcrecs = (xdlclass_t **) xdl_realloc(cf->rcrecs, cf->alloc * sizeof(xdlclass_t *)))) { return -1; } cf->rcrecs = rcrecs; } cf->rcrecs[rcrec->idx] = rcrec; rcrec->line = line; rcrec->size = rec->size; rcrec->ha = rec->ha; rcrec->len1 = rcrec->len2 = 0; rcrec->next = cf->rchash[hi]; cf->rchash[hi] = rcrec; } (pass == 1) ? rcrec->len1++ : rcrec->len2++; rec->ha = (unsigned long) rcrec->idx; hi = (long) XDL_HASHLONG(rec->ha, hbits); rec->next = rhash[hi]; rhash[hi] = rec; return 0; } /* * Trim common prefix from files. * * Note: trimming could affect hunk shifting. But the performance benefit * outweighs the shift change. A diff result with suboptimal shifting is still * valid. */ static void xdl_trim_files(mmfile_t *mf1, mmfile_t *mf2, int64_t reserved, xdfenv_t *xe, mmfile_t *out_mf1, mmfile_t *out_mf2) { mmfile_t msmall, mlarge; /* prefix lines, prefix bytes, suffix lines, suffix bytes */ int64_t plines = 0, pbytes = 0, slines = 0, sbytes = 0, i; /* prefix char pointer for msmall and mlarge */ const char *pp1, *pp2; /* suffix char pointer for msmall and mlarge */ const char *ps1, *ps2; /* reserved must >= 0 for the line boundary adjustment to work */ if (reserved < 0) reserved = 0; if (mf1->size < mf2->size) { memcpy(&msmall, mf1, sizeof(mmfile_t)); memcpy(&mlarge, mf2, sizeof(mmfile_t)); } else { memcpy(&msmall, mf2, sizeof(mmfile_t)); memcpy(&mlarge, mf1, sizeof(mmfile_t)); } pp1 = msmall.ptr, pp2 = mlarge.ptr; for (i = 0; i < msmall.size && *pp1 == *pp2; ++i) { plines += (*pp1 == '\n'); pp1++, pp2++; } ps1 = msmall.ptr + msmall.size - 1, ps2 = mlarge.ptr + mlarge.size - 1; while (ps1 > pp1 && *ps1 == *ps2) { slines += (*ps1 == '\n'); ps1--, ps2--; } /* Retract common prefix and suffix boundaries for reserved lines */ if (plines <= reserved + 1) { plines = 0; } else { i = 0; while (i <= reserved) { pp1--; i += (*pp1 == '\n'); } /* The new mmfile starts at the next char just after '\n' */ pbytes = pp1 - msmall.ptr + 1; plines -= reserved; } if (slines <= reserved + 1) { slines = 0; } else { /* Note: with compiler SIMD support (ex. -O3 -mavx2), this * might perform better than memchr. */ i = 0; while (i <= reserved) { ps1++; i += (*ps1 == '\n'); } /* The new mmfile includes this '\n' */ sbytes = msmall.ptr + msmall.size - ps1 - 1; slines -= reserved; if (msmall.ptr[msmall.size - 1] == '\n') slines -= 1; } xe->nprefix = plines; xe->nsuffix = slines; out_mf1->ptr = mf1->ptr + pbytes; out_mf1->size = mf1->size - pbytes - sbytes; out_mf2->ptr = mf2->ptr + pbytes; out_mf2->size = mf2->size - pbytes - sbytes; } static int xdl_prepare_ctx(unsigned int pass, mmfile_t *mf, int64_t narec, xdlclassifier_t *cf, xdfile_t *xdf) { unsigned int hbits; int64_t nrec, hsize, bsize; uint64_t hav; char const *blk, *cur, *top, *prev; xrecord_t *crec; xrecord_t **recs, **rrecs; xrecord_t **rhash; uint64_t *ha; char *rchg; int64_t *rindex; ha = NULL; rindex = NULL; rchg = NULL; rhash = NULL; recs = NULL; if (xdl_cha_init(&xdf->rcha, sizeof(xrecord_t), narec / 4 + 1) < 0) goto abort; if (!(recs = (xrecord_t **) xdl_malloc(narec * sizeof(xrecord_t *)))) goto abort; { hbits = xdl_hashbits(narec); hsize = ((uint64_t)1) << hbits; if (!(rhash = (xrecord_t **) xdl_malloc(hsize * sizeof(xrecord_t *)))) goto abort; memset(rhash, 0, hsize * sizeof(xrecord_t *)); } nrec = 0; if ((cur = blk = xdl_mmfile_first(mf, &bsize)) != NULL) { for (top = blk + bsize; cur < top; ) { prev = cur; hav = xdl_hash_record(&cur, top); if (nrec >= narec) { narec *= 2; if (!(rrecs = (xrecord_t **) xdl_realloc(recs, narec * sizeof(xrecord_t *)))) goto abort; recs = rrecs; } if (!(crec = xdl_cha_alloc(&xdf->rcha))) goto abort; crec->ptr = prev; crec->size = (long) (cur - prev); crec->ha = hav; recs[nrec++] = crec; if (xdl_classify_record(pass, cf, rhash, hbits, crec) < 0) goto abort; } } if (!(rchg = (char *) xdl_malloc((nrec + 2) * sizeof(char)))) goto abort; memset(rchg, 0, (nrec + 2) * sizeof(char)); if (!(rindex = (int64_t *) xdl_malloc((nrec + 1) * sizeof(int64_t)))) goto abort; if (!(ha = (uint64_t *) xdl_malloc((nrec + 1) * sizeof(uint64_t)))) goto abort; xdf->nrec = nrec; xdf->recs = recs; xdf->hbits = hbits; xdf->rhash = rhash; xdf->rchg = rchg + 1; xdf->rindex = rindex; xdf->nreff = 0; xdf->ha = ha; xdf->dstart = 0; xdf->dend = nrec - 1; return 0; abort: xdl_free(ha); xdl_free(rindex); xdl_free(rchg); xdl_free(rhash); xdl_free(recs); xdl_cha_free(&xdf->rcha); return -1; } static void xdl_free_ctx(xdfile_t *xdf) { xdl_free(xdf->rhash); xdl_free(xdf->rindex); xdl_free(xdf->rchg - 1); xdl_free(xdf->ha); xdl_free(xdf->recs); xdl_cha_free(&xdf->rcha); } /* Reserved lines for trimming, to leave room for shifting */ #define TRIM_RESERVED_LINES 100 int xdl_prepare_env(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, xdfenv_t *xe) { int64_t enl1, enl2, sample; mmfile_t tmf1, tmf2; xdlclassifier_t cf; memset(&cf, 0, sizeof(cf)); sample = XDL_GUESS_NLINES1; enl1 = xdl_guess_lines(mf1, sample) + 1; enl2 = xdl_guess_lines(mf2, sample) + 1; if (xdl_init_classifier(&cf, enl1 + enl2 + 1, xpp->flags) < 0) return -1; xdl_trim_files(mf1, mf2, TRIM_RESERVED_LINES, xe, &tmf1, &tmf2); if (xdl_prepare_ctx(1, &tmf1, enl1, &cf, &xe->xdf1) < 0) { xdl_free_classifier(&cf); return -1; } if (xdl_prepare_ctx(2, &tmf2, enl2, &cf, &xe->xdf2) < 0) { xdl_free_ctx(&xe->xdf1); xdl_free_classifier(&cf); return -1; } if (xdl_optimize_ctxs(&cf, &xe->xdf1, &xe->xdf2) < 0) { xdl_free_ctx(&xe->xdf2); xdl_free_ctx(&xe->xdf1); xdl_free_classifier(&cf); return -1; } xdl_free_classifier(&cf); return 0; } void xdl_free_env(xdfenv_t *xe) { xdl_free_ctx(&xe->xdf2); xdl_free_ctx(&xe->xdf1); } static int xdl_clean_mmatch(char const *dis, int64_t i, int64_t s, int64_t e) { int64_t r, rdis0, rpdis0, rdis1, rpdis1; /* * Limits the window the is examined during the similar-lines * scan. The loops below stops when dis[i - r] == 1 (line that * has no match), but there are corner cases where the loop * proceed all the way to the extremities by causing huge * performance penalties in case of big files. */ if (i - s > XDL_SIMSCAN_WINDOW) s = i - XDL_SIMSCAN_WINDOW; if (e - i > XDL_SIMSCAN_WINDOW) e = i + XDL_SIMSCAN_WINDOW; /* * Scans the lines before 'i' to find a run of lines that either * have no match (dis[j] == 0) or have multiple matches (dis[j] > 1). * Note that we always call this function with dis[i] > 1, so the * current line (i) is already a multimatch line. */ for (r = 1, rdis0 = 0, rpdis0 = 1; (i - r) >= s; r++) { if (!dis[i - r]) rdis0++; else if (dis[i - r] == 2) rpdis0++; else break; } /* * If the run before the line 'i' found only multimatch lines, we * return 0 and hence we don't make the current line (i) discarded. * We want to discard multimatch lines only when they appear in the * middle of runs with nomatch lines (dis[j] == 0). */ if (rdis0 == 0) return 0; for (r = 1, rdis1 = 0, rpdis1 = 1; (i + r) <= e; r++) { if (!dis[i + r]) rdis1++; else if (dis[i + r] == 2) rpdis1++; else break; } /* * If the run after the line 'i' found only multimatch lines, we * return 0 and hence we don't make the current line (i) discarded. */ if (rdis1 == 0) return 0; rdis1 += rdis0; rpdis1 += rpdis0; return rpdis1 * XDL_KPDIS_RUN < (rpdis1 + rdis1); } /* * Try to reduce the problem complexity, discard records that have no * matches on the other file. Also, lines that have multiple matches * might be potentially discarded if they happear in a run of discardable. */ static int xdl_cleanup_records(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xdf2) { int64_t i, nm, nreff, mlim; xrecord_t **recs; xdlclass_t *rcrec; char *dis, *dis1, *dis2; if (!(dis = (char *) xdl_malloc(xdf1->nrec + xdf2->nrec + 2))) { return -1; } memset(dis, 0, xdf1->nrec + xdf2->nrec + 2); dis1 = dis; dis2 = dis1 + xdf1->nrec + 1; if ((mlim = xdl_bogosqrt(xdf1->nrec)) > XDL_MAX_EQLIMIT) mlim = XDL_MAX_EQLIMIT; for (i = xdf1->dstart, recs = &xdf1->recs[xdf1->dstart]; i <= xdf1->dend; i++, recs++) { rcrec = cf->rcrecs[(*recs)->ha]; nm = rcrec ? rcrec->len2 : 0; dis1[i] = (nm == 0) ? 0: (nm >= mlim) ? 2: 1; } if ((mlim = xdl_bogosqrt(xdf2->nrec)) > XDL_MAX_EQLIMIT) mlim = XDL_MAX_EQLIMIT; for (i = xdf2->dstart, recs = &xdf2->recs[xdf2->dstart]; i <= xdf2->dend; i++, recs++) { rcrec = cf->rcrecs[(*recs)->ha]; nm = rcrec ? rcrec->len1 : 0; dis2[i] = (nm == 0) ? 0: (nm >= mlim) ? 2: 1; } for (nreff = 0, i = xdf1->dstart, recs = &xdf1->recs[xdf1->dstart]; i <= xdf1->dend; i++, recs++) { if (dis1[i] == 1 || (dis1[i] == 2 && !xdl_clean_mmatch(dis1, i, xdf1->dstart, xdf1->dend))) { xdf1->rindex[nreff] = i; xdf1->ha[nreff] = (*recs)->ha; nreff++; } else xdf1->rchg[i] = 1; } xdf1->nreff = nreff; for (nreff = 0, i = xdf2->dstart, recs = &xdf2->recs[xdf2->dstart]; i <= xdf2->dend; i++, recs++) { if (dis2[i] == 1 || (dis2[i] == 2 && !xdl_clean_mmatch(dis2, i, xdf2->dstart, xdf2->dend))) { xdf2->rindex[nreff] = i; xdf2->ha[nreff] = (*recs)->ha; nreff++; } else xdf2->rchg[i] = 1; } xdf2->nreff = nreff; xdl_free(dis); return 0; } /* * Early trim initial and terminal matching records. */ static int xdl_trim_ends(xdfile_t *xdf1, xdfile_t *xdf2) { int64_t i, lim; xrecord_t **recs1, **recs2; recs1 = xdf1->recs; recs2 = xdf2->recs; for (i = 0, lim = XDL_MIN(xdf1->nrec, xdf2->nrec); i < lim; i++, recs1++, recs2++) if ((*recs1)->ha != (*recs2)->ha) break; xdf1->dstart = xdf2->dstart = i; recs1 = xdf1->recs + xdf1->nrec - 1; recs2 = xdf2->recs + xdf2->nrec - 1; for (lim -= i, i = 0; i < lim; i++, recs1--, recs2--) if ((*recs1)->ha != (*recs2)->ha) break; xdf1->dend = xdf1->nrec - i - 1; xdf2->dend = xdf2->nrec - i - 1; return 0; } static int xdl_optimize_ctxs(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xdf2) { if (xdl_trim_ends(xdf1, xdf2) < 0 || xdl_cleanup_records(cf, xdf1, xdf2) < 0) { return -1; } return 0; }