Merge branch 'ee/clean-test-fixes'
[git] / xdiff / xemit.c
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
28 static long xdl_get_rec(xdfile_t *xdf, long ri, char const **rec);
29 static int xdl_emit_record(xdfile_t *xdf, long ri, char const *pre, xdemitcb_t *ecb);
30
31
32
33
34 static 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
42 static 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  */
61 xdchange_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
107 static 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
123 static int xdl_emit_common(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
124                            xdemitconf_t const *xecfg) {
125         xdfile_t *xdf = &xe->xdf2;
126         const char *rchg = xdf->rchg;
127         long ix;
128
129         for (ix = 0; ix < xdf->nrec; ix++) {
130                 if (rchg[ix])
131                         continue;
132                 if (xdl_emit_record(xdf, ix, "", ecb))
133                         return -1;
134         }
135         return 0;
136 }
137
138 struct func_line {
139         long len;
140         char buf[80];
141 };
142
143 static long get_func_line(xdfenv_t *xe, xdemitconf_t const *xecfg,
144                           struct func_line *func_line, long start, long limit)
145 {
146         find_func_t ff = xecfg->find_func ? xecfg->find_func : def_ff;
147         long l, size, step = (start > limit) ? -1 : 1;
148         char *buf, dummy[1];
149
150         buf = func_line ? func_line->buf : dummy;
151         size = func_line ? sizeof(func_line->buf) : sizeof(dummy);
152
153         for (l = start; l != limit && 0 <= l && l < xe->xdf1.nrec; l += step) {
154                 const char *rec;
155                 long reclen = xdl_get_rec(&xe->xdf1, l, &rec);
156                 long len = ff(rec, reclen, buf, size, xecfg->find_func_priv);
157                 if (len >= 0) {
158                         if (func_line)
159                                 func_line->len = len;
160                         return l;
161                 }
162         }
163         return -1;
164 }
165
166 int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
167                   xdemitconf_t const *xecfg) {
168         long s1, s2, e1, e2, lctx;
169         xdchange_t *xch, *xche;
170         long funclineprev = -1;
171         struct func_line func_line = { 0 };
172
173         if (xecfg->flags & XDL_EMIT_COMMON)
174                 return xdl_emit_common(xe, xscr, ecb, xecfg);
175
176         for (xch = xscr; xch; xch = xche->next) {
177                 xche = xdl_get_hunk(&xch, xecfg);
178                 if (!xch)
179                         break;
180
181                 s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
182                 s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
183
184                 if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
185                         long fs1 = get_func_line(xe, xecfg, NULL, xch->i1, -1);
186                         if (fs1 < 0)
187                                 fs1 = 0;
188                         if (fs1 < s1) {
189                                 s2 -= s1 - fs1;
190                                 s1 = fs1;
191                         }
192                 }
193
194  again:
195                 lctx = xecfg->ctxlen;
196                 lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1));
197                 lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2));
198
199                 e1 = xche->i1 + xche->chg1 + lctx;
200                 e2 = xche->i2 + xche->chg2 + lctx;
201
202                 if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
203                         long fe1 = get_func_line(xe, xecfg, NULL,
204                                                  xche->i1 + xche->chg1,
205                                                  xe->xdf1.nrec);
206                         if (fe1 < 0)
207                                 fe1 = xe->xdf1.nrec;
208                         if (fe1 > e1) {
209                                 e2 += fe1 - e1;
210                                 e1 = fe1;
211                         }
212
213                         /*
214                          * Overlap with next change?  Then include it
215                          * in the current hunk and start over to find
216                          * its new end.
217                          */
218                         if (xche->next) {
219                                 long l = xche->next->i1;
220                                 if (l <= e1 ||
221                                     get_func_line(xe, xecfg, NULL, l, e1) < 0) {
222                                         xche = xche->next;
223                                         goto again;
224                                 }
225                         }
226                 }
227
228                 /*
229                  * Emit current hunk header.
230                  */
231
232                 if (xecfg->flags & XDL_EMIT_FUNCNAMES) {
233                         get_func_line(xe, xecfg, &func_line,
234                                       s1 - 1, funclineprev);
235                         funclineprev = s1 - 1;
236                 }
237                 if (xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2,
238                                       func_line.buf, func_line.len, ecb) < 0)
239                         return -1;
240
241                 /*
242                  * Emit pre-context.
243                  */
244                 for (; s2 < xch->i2; s2++)
245                         if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
246                                 return -1;
247
248                 for (s1 = xch->i1, s2 = xch->i2;; xch = xch->next) {
249                         /*
250                          * Merge previous with current change atom.
251                          */
252                         for (; s1 < xch->i1 && s2 < xch->i2; s1++, s2++)
253                                 if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
254                                         return -1;
255
256                         /*
257                          * Removes lines from the first file.
258                          */
259                         for (s1 = xch->i1; s1 < xch->i1 + xch->chg1; s1++)
260                                 if (xdl_emit_record(&xe->xdf1, s1, "-", ecb) < 0)
261                                         return -1;
262
263                         /*
264                          * Adds lines from the second file.
265                          */
266                         for (s2 = xch->i2; s2 < xch->i2 + xch->chg2; s2++)
267                                 if (xdl_emit_record(&xe->xdf2, s2, "+", ecb) < 0)
268                                         return -1;
269
270                         if (xch == xche)
271                                 break;
272                         s1 = xch->i1 + xch->chg1;
273                         s2 = xch->i2 + xch->chg2;
274                 }
275
276                 /*
277                  * Emit post-context.
278                  */
279                 for (s2 = xche->i2 + xche->chg2; s2 < e2; s2++)
280                         if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
281                                 return -1;
282         }
283
284         return 0;
285 }