xemit.c 7.99 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
/*
 *  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
16 17
 *  License along with this library; if not, see
 *  <http://www.gnu.org/licenses/>.
18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33
 *
 *  Davide Libenzi <davidel@xmailserver.org>
 *
 */

#include "xinclude.h"

static long xdl_get_rec(xdfile_t *xdf, long ri, char const **rec) {

	*rec = xdf->recs[ri]->ptr;

	return xdf->recs[ri]->size;
}


static int xdl_emit_record(xdfile_t *xdf, long ri, char const *pre, xdemitcb_t *ecb) {
34
	long size, psize = strlen(pre);
35 36 37 38 39 40 41 42 43 44 45 46 47 48 49
	char const *rec;

	size = xdl_get_rec(xdf, ri, &rec);
	if (xdl_emit_diffrec(rec, size, pre, psize, ecb) < 0) {

		return -1;
	}

	return 0;
}


/*
 * Starting at the passed change atom, find the latest change atom to be included
 * inside the differential hunk according to the specified configuration.
50
 * Also advance xscr if the first changes must be discarded.
51
 */
52 53 54
xdchange_t *xdl_get_hunk(xdchange_t **xscr, xdemitconf_t const *xecfg)
{
	xdchange_t *xch, *xchp, *lxch;
55
	long max_common = 2 * xecfg->ctxlen + xecfg->interhunkctxlen;
56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
	long max_ignorable = xecfg->ctxlen;
	unsigned long ignored = 0; /* number of ignored blank lines */

	/* remove ignorable changes that are too far before other changes */
	for (xchp = *xscr; xchp && xchp->ignore; xchp = xchp->next) {
		xch = xchp->next;

		if (xch == NULL ||
		    xch->i1 - (xchp->i1 + xchp->chg1) >= max_ignorable)
			*xscr = xch;
	}

	if (*xscr == NULL)
		return NULL;

	lxch = *xscr;
72

73 74 75
	for (xchp = *xscr, xch = xchp->next; xch; xchp = xch, xch = xch->next) {
		long distance = xch->i1 - (xchp->i1 + xchp->chg1);
		if (distance > max_common)
76 77
			break;

78 79 80 81 82 83
		if (distance < max_ignorable && (!xch->ignore || lxch == xchp)) {
			lxch = xch;
			ignored = 0;
		} else if (distance < max_ignorable && xch->ignore) {
			ignored += xch->chg2;
		} else if (lxch != xchp &&
84
			   xch->i1 + ignored - (lxch->i1 + lxch->chg1) > max_common) {
85 86 87 88 89 90 91 92 93 94
			break;
		} else if (!xch->ignore) {
			lxch = xch;
			ignored = 0;
		} else {
			ignored += xch->chg2;
		}
	}

	return lxch;
95 96 97 98 99 100 101
}


static long def_ff(const char *rec, long len, char *buf, long sz, void *priv)
{
	if (len > 0 &&
			(isalpha((unsigned char)*rec) || /* identifier? */
102
			 *rec == '_' || /* also identifier? */
103 104 105 106 107 108 109 110 111 112 113
			 *rec == '$')) { /* identifiers from VMS and other esoterico */
		if (len > sz)
			len = sz;
		while (0 < len && isspace((unsigned char)rec[len - 1]))
			len--;
		memcpy(buf, rec, len);
		return len;
	}
	return -1;
}

114 115 116 117 118 119 120 121 122
static long match_func_rec(xdfile_t *xdf, xdemitconf_t const *xecfg, long ri,
			   char *buf, long sz)
{
	const char *rec;
	long len = xdl_get_rec(xdf, ri, &rec);
	if (!xecfg->find_func)
		return def_ff(rec, len, buf, sz, xecfg->find_func_priv);
	return xecfg->find_func(rec, len, buf, sz, xecfg->find_func_priv);
}
123

124 125 126 127
static int is_func_rec(xdfile_t *xdf, xdemitconf_t const *xecfg, long ri)
{
	char dummy[1];
	return match_func_rec(xdf, xecfg, ri, dummy, sizeof(dummy)) >= 0;
128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144
}

struct func_line {
	long len;
	char buf[80];
};

static long get_func_line(xdfenv_t *xe, xdemitconf_t const *xecfg,
			  struct func_line *func_line, long start, long limit)
{
	long l, size, step = (start > limit) ? -1 : 1;
	char *buf, dummy[1];

	buf = func_line ? func_line->buf : dummy;
	size = func_line ? sizeof(func_line->buf) : sizeof(dummy);

	for (l = start; l != limit && 0 <= l && l < xe->xdf1.nrec; l += step) {
145
		long len = match_func_rec(&xe->xdf1, xecfg, l, buf, size);
146 147 148 149 150 151 152 153 154
		if (len >= 0) {
			if (func_line)
				func_line->len = len;
			return l;
		}
	}
	return -1;
}

155 156 157 158 159 160 161 162 163 164 165 166
static int is_empty_rec(xdfile_t *xdf, long ri)
{
	const char *rec;
	long len = xdl_get_rec(xdf, ri, &rec);

	while (len > 0 && XDL_ISSPACE(*rec)) {
		rec++;
		len--;
	}
	return !len;
}

167 168 169 170 171 172 173 174
int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
		  xdemitconf_t const *xecfg) {
	long s1, s2, e1, e2, lctx;
	xdchange_t *xch, *xche;
	long funclineprev = -1;
	struct func_line func_line = { 0 };

	for (xch = xscr; xch; xch = xche->next) {
175
		xdchange_t *xchp = xch;
176 177 178
		xche = xdl_get_hunk(&xch, xecfg);
		if (!xch)
			break;
179

180
pre_context_calculation:
181 182 183 184
		s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
		s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);

		if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211
			long fs1, i1 = xch->i1;

			/* Appended chunk? */
			if (i1 >= xe->xdf1.nrec) {
				long i2 = xch->i2;

				/*
				 * We don't need additional context if
				 * a whole function was added.
				 */
				while (i2 < xe->xdf2.nrec) {
					if (is_func_rec(&xe->xdf2, xecfg, i2))
						goto post_context_calculation;
					i2++;
				}

				/*
				 * Otherwise get more context from the
				 * pre-image.
				 */
				i1 = xe->xdf1.nrec - 1;
			}

			fs1 = get_func_line(xe, xecfg, NULL, i1, -1);
			while (fs1 > 0 && !is_empty_rec(&xe->xdf1, fs1 - 1) &&
			       !is_func_rec(&xe->xdf1, xecfg, fs1 - 1))
				fs1--;
212 213 214
			if (fs1 < 0)
				fs1 = 0;
			if (fs1 < s1) {
215
				s2 = XDL_MAX(s2 - (s1 - fs1), 0);
216
				s1 = fs1;
217 218 219 220 221 222 223 224 225 226 227 228 229 230 231

				/*
				 * Did we extend context upwards into an
				 * ignored change?
				 */
				while (xchp != xch &&
				       xchp->i1 + xchp->chg1 <= s1 &&
				       xchp->i2 + xchp->chg2 <= s2)
					xchp = xchp->next;

				/* If so, show it after all. */
				if (xchp != xch) {
					xch = xchp;
					goto pre_context_calculation;
				}
232 233 234
			}
		}

235
 post_context_calculation:
236 237 238 239 240 241 242 243 244 245 246
		lctx = xecfg->ctxlen;
		lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1));
		lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2));

		e1 = xche->i1 + xche->chg1 + lctx;
		e2 = xche->i2 + xche->chg2 + lctx;

		if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
			long fe1 = get_func_line(xe, xecfg, NULL,
						 xche->i1 + xche->chg1,
						 xe->xdf1.nrec);
247 248
			while (fe1 > 0 && is_empty_rec(&xe->xdf1, fe1 - 1))
				fe1--;
249 250 251
			if (fe1 < 0)
				fe1 = xe->xdf1.nrec;
			if (fe1 > e1) {
252
				e2 = XDL_MIN(e2 + (fe1 - e1), xe->xdf2.nrec);
253 254 255 256 257 258 259 260 261
				e1 = fe1;
			}

			/*
			 * Overlap with next change?  Then include it
			 * in the current hunk and start over to find
			 * its new end.
			 */
			if (xche->next) {
262 263 264
				long l = XDL_MIN(xche->next->i1,
						 xe->xdf1.nrec - 1);
				if (l - xecfg->ctxlen <= e1 ||
265 266
				    get_func_line(xe, xecfg, NULL, l, e1) < 0) {
					xche = xche->next;
267
					goto post_context_calculation;
268 269 270 271 272 273 274 275 276 277 278 279 280
				}
			}
		}

		/*
		 * Emit current hunk header.
		 */

		if (xecfg->flags & XDL_EMIT_FUNCNAMES) {
			get_func_line(xe, xecfg, &func_line,
				      s1 - 1, funclineprev);
			funclineprev = s1 - 1;
		}
281 282
		if (!(xecfg->flags & XDL_EMIT_NO_HUNK_HDR) &&
		    xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2,
283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330
				      func_line.buf, func_line.len, ecb) < 0)
			return -1;

		/*
		 * Emit pre-context.
		 */
		for (; s2 < xch->i2; s2++)
			if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
				return -1;

		for (s1 = xch->i1, s2 = xch->i2;; xch = xch->next) {
			/*
			 * Merge previous with current change atom.
			 */
			for (; s1 < xch->i1 && s2 < xch->i2; s1++, s2++)
				if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
					return -1;

			/*
			 * Removes lines from the first file.
			 */
			for (s1 = xch->i1; s1 < xch->i1 + xch->chg1; s1++)
				if (xdl_emit_record(&xe->xdf1, s1, "-", ecb) < 0)
					return -1;

			/*
			 * Adds lines from the second file.
			 */
			for (s2 = xch->i2; s2 < xch->i2 + xch->chg2; s2++)
				if (xdl_emit_record(&xe->xdf2, s2, "+", ecb) < 0)
					return -1;

			if (xch == xche)
				break;
			s1 = xch->i1 + xch->chg1;
			s2 = xch->i2 + xch->chg2;
		}

		/*
		 * Emit post-context.
		 */
		for (s2 = xche->i2 + xche->chg2; s2 < e2; s2++)
			if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
				return -1;
	}

	return 0;
}