gitweb: A couple of page title tweaking
[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 static xdchange_t *xdl_get_hunk(xdchange_t *xscr, xdemitconf_t const *xecfg);
31
32
33
34
35 static long xdl_get_rec(xdfile_t *xdf, long ri, char const **rec) {
36
37         *rec = xdf->recs[ri]->ptr;
38
39         return xdf->recs[ri]->size;
40 }
41
42
43 static int xdl_emit_record(xdfile_t *xdf, long ri, char const *pre, xdemitcb_t *ecb) {
44         long size, psize = strlen(pre);
45         char const *rec;
46
47         size = xdl_get_rec(xdf, ri, &rec);
48         if (xdl_emit_diffrec(rec, size, pre, psize, ecb) < 0) {
49
50                 return -1;
51         }
52
53         return 0;
54 }
55
56
57 /*
58  * Starting at the passed change atom, find the latest change atom to be included
59  * inside the differential hunk according to the specified configuration.
60  */
61 static xdchange_t *xdl_get_hunk(xdchange_t *xscr, xdemitconf_t const *xecfg) {
62         xdchange_t *xch, *xchp;
63
64         for (xchp = xscr, xch = xscr->next; xch; xchp = xch, xch = xch->next)
65                 if (xch->i1 - (xchp->i1 + xchp->chg1) > 2 * xecfg->ctxlen)
66                         break;
67
68         return xchp;
69 }
70
71
72 static void xdl_find_func(xdfile_t *xf, long i, char *buf, long sz, long *ll) {
73
74         /*
75          * Be quite stupid about this for now.  Find a line in the old file
76          * before the start of the hunk (and context) which starts with a
77          * plausible character.
78          */
79
80         const char *rec;
81         long len;
82
83         *ll = 0;
84         while (i-- > 0) {
85                 len = xdl_get_rec(xf, i, &rec);
86                 if (len > 0 &&
87                     (isalpha((unsigned char)*rec) || /* identifier? */
88                      *rec == '_' ||     /* also identifier? */
89                      *rec == '(' ||     /* lisp defun? */
90                      *rec == '#')) {    /* #define? */
91                         if (len > sz)
92                                 len = sz;
93                         if (len && rec[len - 1] == '\n')
94                                 len--;
95                         memcpy(buf, rec, len);
96                         *ll = len;
97                         return;
98                 }
99         }
100 }
101
102
103 int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
104                   xdemitconf_t const *xecfg) {
105         long s1, s2, e1, e2, lctx;
106         xdchange_t *xch, *xche;
107         char funcbuf[40];
108         long funclen = 0;
109
110         for (xch = xche = xscr; xch; xch = xche->next) {
111                 xche = xdl_get_hunk(xch, xecfg);
112
113                 s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
114                 s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
115
116                 lctx = xecfg->ctxlen;
117                 lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1));
118                 lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2));
119
120                 e1 = xche->i1 + xche->chg1 + lctx;
121                 e2 = xche->i2 + xche->chg2 + lctx;
122
123                 /*
124                  * Emit current hunk header.
125                  */
126
127                 if (xecfg->flags & XDL_EMIT_FUNCNAMES) {
128                         xdl_find_func(&xe->xdf1, s1, funcbuf,
129                                       sizeof(funcbuf), &funclen);
130                 }
131                 if (xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2,
132                                       funcbuf, funclen, ecb) < 0)
133                         return -1;
134
135                 /*
136                  * Emit pre-context.
137                  */
138                 for (; s1 < xch->i1; s1++)
139                         if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
140                                 return -1;
141
142                 for (s1 = xch->i1, s2 = xch->i2;; xch = xch->next) {
143                         /*
144                          * Merge previous with current change atom.
145                          */
146                         for (; s1 < xch->i1 && s2 < xch->i2; s1++, s2++)
147                                 if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
148                                         return -1;
149
150                         /*
151                          * Removes lines from the first file.
152                          */
153                         for (s1 = xch->i1; s1 < xch->i1 + xch->chg1; s1++)
154                                 if (xdl_emit_record(&xe->xdf1, s1, "-", ecb) < 0)
155                                         return -1;
156
157                         /*
158                          * Adds lines from the second file.
159                          */
160                         for (s2 = xch->i2; s2 < xch->i2 + xch->chg2; s2++)
161                                 if (xdl_emit_record(&xe->xdf2, s2, "+", ecb) < 0)
162                                         return -1;
163
164                         if (xch == xche)
165                                 break;
166                         s1 = xch->i1 + xch->chg1;
167                         s2 = xch->i2 + xch->chg2;
168                 }
169
170                 /*
171                  * Emit post-context.
172                  */
173                 for (s1 = xche->i1 + xche->chg1; s1 < e1; s1++)
174                         if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
175                                 return -1;
176         }
177
178         return 0;
179 }
180