Andrew's git - gitweb.git/blob

   1/*
   2 *  LibXDiff by Davide Libenzi ( File Differential Library )
   3 *  Copyright (C) 2003  Davide Libenzi
   4 *
   5 *  This library is free software; you can redistribute it and/or
   6 *  modify it under the terms of the GNU Lesser General Public
   7 *  License as published by the Free Software Foundation; either
   8 *  version 2.1 of the License, or (at your option) any later version.
   9 *
  10 *  This library is distributed in the hope that it will be useful,
  11 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 *  Lesser General Public License for more details.
  14 *
  15 *  You should have received a copy of the GNU Lesser General Public
  16 *  License along with this library; if not, write to the Free Software
  17 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18 *
  19 *  Davide Libenzi <davidel@xmailserver.org>
  20 *
  21 */
  22
  23#include "xinclude.h"
  24
  25
  26
  27
  28static long xdl_get_rec(xdfile_t *xdf, long ri, char const **rec);
  29static int xdl_emit_record(xdfile_t *xdf, long ri, char const *pre, xdemitcb_t *ecb);
  30
  31
  32
  33
  34static long xdl_get_rec(xdfile_t *xdf, long ri, char const **rec) {
  35
  36        *rec = xdf->recs[ri]->ptr;
  37
  38        return xdf->recs[ri]->size;
  39}
  40
  41
  42static int xdl_emit_record(xdfile_t *xdf, long ri, char const *pre, xdemitcb_t *ecb) {
  43        long size, psize = strlen(pre);
  44        char const *rec;
  45
  46        size = xdl_get_rec(xdf, ri, &rec);
  47        if (xdl_emit_diffrec(rec, size, pre, psize, ecb) < 0) {
  48
  49                return -1;
  50        }
  51
  52        return 0;
  53}
  54
  55
  56/*
  57 * Starting at the passed change atom, find the latest change atom to be included
  58 * inside the differential hunk according to the specified configuration.
  59 * Also advance xscr if the first changes must be discarded.
  60 */
  61xdchange_t *xdl_get_hunk(xdchange_t **xscr, xdemitconf_t const *xecfg)
  62{
  63        xdchange_t *xch, *xchp, *lxch;
  64        long max_common = 2 * xecfg->ctxlen + xecfg->interhunkctxlen;
  65        long max_ignorable = xecfg->ctxlen;
  66        unsigned long ignored = 0; /* number of ignored blank lines */
  67
  68        /* remove ignorable changes that are too far before other changes */
  69        for (xchp = *xscr; xchp && xchp->ignore; xchp = xchp->next) {
  70                xch = xchp->next;
  71
  72                if (xch == NULL ||
  73                    xch->i1 - (xchp->i1 + xchp->chg1) >= max_ignorable)
  74                        *xscr = xch;
  75        }
  76
  77        if (*xscr == NULL)
  78                return NULL;
  79
  80        lxch = *xscr;
  81
  82        for (xchp = *xscr, xch = xchp->next; xch; xchp = xch, xch = xch->next) {
  83                long distance = xch->i1 - (xchp->i1 + xchp->chg1);
  84                if (distance > max_common)
  85                        break;
  86
  87                if (distance < max_ignorable && (!xch->ignore || lxch == xchp)) {
  88                        lxch = xch;
  89                        ignored = 0;
  90                } else if (distance < max_ignorable && xch->ignore) {
  91                        ignored += xch->chg2;
  92                } else if (lxch != xchp &&
  93                           xch->i1 + ignored - (lxch->i1 + lxch->chg1) > max_common) {
  94                        break;
  95                } else if (!xch->ignore) {
  96                        lxch = xch;
  97                        ignored = 0;
  98                } else {
  99                        ignored += xch->chg2;
 100                }
 101        }
 102
 103        return lxch;
 104}
 105
 106
 107static long def_ff(const char *rec, long len, char *buf, long sz, void *priv)
 108{
 109        if (len > 0 &&
 110                        (isalpha((unsigned char)*rec) || /* identifier? */
 111                         *rec == '_' || /* also identifier? */
 112                         *rec == '$')) { /* identifiers from VMS and other esoterico */
 113                if (len > sz)
 114                        len = sz;
 115                while (0 < len && isspace((unsigned char)rec[len - 1]))
 116                        len--;
 117                memcpy(buf, rec, len);
 118                return len;
 119        }
 120        return -1;
 121}
 122
 123static long match_func_rec(xdfile_t *xdf, xdemitconf_t const *xecfg, long ri,
 124                           char *buf, long sz)
 125{
 126        const char *rec;
 127        long len = xdl_get_rec(xdf, ri, &rec);
 128        if (!xecfg->find_func)
 129                return def_ff(rec, len, buf, sz, xecfg->find_func_priv);
 130        return xecfg->find_func(rec, len, buf, sz, xecfg->find_func_priv);
 131}
 132
 133struct func_line {
 134        long len;
 135        char buf[80];
 136};
 137
 138static long get_func_line(xdfenv_t *xe, xdemitconf_t const *xecfg,
 139                          struct func_line *func_line, long start, long limit)
 140{
 141        long l, size, step = (start > limit) ? -1 : 1;
 142        char *buf, dummy[1];
 143
 144        buf = func_line ? func_line->buf : dummy;
 145        size = func_line ? sizeof(func_line->buf) : sizeof(dummy);
 146
 147        for (l = start; l != limit && 0 <= l && l < xe->xdf1.nrec; l += step) {
 148                long len = match_func_rec(&xe->xdf1, xecfg, l, buf, size);
 149                if (len >= 0) {
 150                        if (func_line)
 151                                func_line->len = len;
 152                        return l;
 153                }
 154        }
 155        return -1;
 156}
 157
 158static int is_empty_rec(xdfile_t *xdf, long ri)
 159{
 160        const char *rec;
 161        long len = xdl_get_rec(xdf, ri, &rec);
 162
 163        while (len > 0 && XDL_ISSPACE(*rec)) {
 164                rec++;
 165                len--;
 166        }
 167        return !len;
 168}
 169
 170int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
 171                  xdemitconf_t const *xecfg) {
 172        long s1, s2, e1, e2, lctx;
 173        xdchange_t *xch, *xche;
 174        long funclineprev = -1;
 175        struct func_line func_line = { 0 };
 176
 177        for (xch = xscr; xch; xch = xche->next) {
 178                xche = xdl_get_hunk(&xch, xecfg);
 179                if (!xch)
 180                        break;
 181
 182                s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
 183                s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
 184
 185                if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
 186                        long fs1, i1 = xch->i1;
 187
 188                        /* Appended chunk? */
 189                        if (i1 >= xe->xdf1.nrec) {
 190                                char dummy[1];
 191                                long i2 = xch->i2;
 192
 193                                /*
 194                                 * We don't need additional context if
 195                                 * a whole function was added, possibly
 196                                 * starting with empty lines.
 197                                 */
 198                                while (i2 < xe->xdf2.nrec &&
 199                                       is_empty_rec(&xe->xdf2, i2))
 200                                        i2++;
 201                                if (i2 < xe->xdf2.nrec &&
 202                                    match_func_rec(&xe->xdf2, xecfg, i2,
 203                                                   dummy, sizeof(dummy)) >= 0)
 204                                        goto post_context_calculation;
 205
 206                                /*
 207                                 * Otherwise get more context from the
 208                                 * pre-image.
 209                                 */
 210                                i1 = xe->xdf1.nrec - 1;
 211                        }
 212
 213                        fs1 = get_func_line(xe, xecfg, NULL, i1, -1);
 214                        if (fs1 < 0)
 215                                fs1 = 0;
 216                        if (fs1 < s1) {
 217                                s2 -= s1 - fs1;
 218                                s1 = fs1;
 219                        }
 220                }
 221
 222 post_context_calculation:
 223                lctx = xecfg->ctxlen;
 224                lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1));
 225                lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2));
 226
 227                e1 = xche->i1 + xche->chg1 + lctx;
 228                e2 = xche->i2 + xche->chg2 + lctx;
 229
 230                if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
 231                        long fe1 = get_func_line(xe, xecfg, NULL,
 232                                                 xche->i1 + xche->chg1,
 233                                                 xe->xdf1.nrec);
 234                        while (fe1 > 0 && is_empty_rec(&xe->xdf1, fe1 - 1))
 235                                fe1--;
 236                        if (fe1 < 0)
 237                                fe1 = xe->xdf1.nrec;
 238                        if (fe1 > e1) {
 239                                e2 += fe1 - e1;
 240                                e1 = fe1;
 241                        }
 242
 243                        /*
 244                         * Overlap with next change?  Then include it
 245                         * in the current hunk and start over to find
 246                         * its new end.
 247                         */
 248                        if (xche->next) {
 249                                long l = XDL_MIN(xche->next->i1,
 250                                                 xe->xdf1.nrec - 1);
 251                                if (l - xecfg->ctxlen <= e1 ||
 252                                    get_func_line(xe, xecfg, NULL, l, e1) < 0) {
 253                                        xche = xche->next;
 254                                        goto post_context_calculation;
 255                                }
 256                        }
 257                }
 258
 259                /*
 260                 * Emit current hunk header.
 261                 */
 262
 263                if (xecfg->flags & XDL_EMIT_FUNCNAMES) {
 264                        get_func_line(xe, xecfg, &func_line,
 265                                      s1 - 1, funclineprev);
 266                        funclineprev = s1 - 1;
 267                }
 268                if (xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2,
 269                                      func_line.buf, func_line.len, ecb) < 0)
 270                        return -1;
 271
 272                /*
 273                 * Emit pre-context.
 274                 */
 275                for (; s2 < xch->i2; s2++)
 276                        if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
 277                                return -1;
 278
 279                for (s1 = xch->i1, s2 = xch->i2;; xch = xch->next) {
 280                        /*
 281                         * Merge previous with current change atom.
 282                         */
 283                        for (; s1 < xch->i1 && s2 < xch->i2; s1++, s2++)
 284                                if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
 285                                        return -1;
 286
 287                        /*
 288                         * Removes lines from the first file.
 289                         */
 290                        for (s1 = xch->i1; s1 < xch->i1 + xch->chg1; s1++)
 291                                if (xdl_emit_record(&xe->xdf1, s1, "-", ecb) < 0)
 292                                        return -1;
 293
 294                        /*
 295                         * Adds lines from the second file.
 296                         */
 297                        for (s2 = xch->i2; s2 < xch->i2 + xch->chg2; s2++)
 298                                if (xdl_emit_record(&xe->xdf2, s2, "+", ecb) < 0)
 299                                        return -1;
 300
 301                        if (xch == xche)
 302                                break;
 303                        s1 = xch->i1 + xch->chg1;
 304                        s2 = xch->i2 + xch->chg2;
 305                }
 306
 307                /*
 308                 * Emit post-context.
 309                 */
 310                for (s2 = xche->i2 + xche->chg2; s2 < e2; s2++)
 311                        if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
 312                                return -1;
 313        }
 314
 315        return 0;
 316}