trim_common_tail: brown paper bag fix.
[git/git.git] / xdiff-interface.c
1 #include "cache.h"
2 #include "xdiff-interface.h"
3
4 static int parse_num(char **cp_p, int *num_p)
5 {
6 char *cp = *cp_p;
7 int num = 0;
8 int read_some;
9
10 while ('0' <= *cp && *cp <= '9')
11 num = num * 10 + *cp++ - '0';
12 if (!(read_some = cp - *cp_p))
13 return -1;
14 *cp_p = cp;
15 *num_p = num;
16 return 0;
17 }
18
19 int parse_hunk_header(char *line, int len,
20 int *ob, int *on,
21 int *nb, int *nn)
22 {
23 char *cp;
24 cp = line + 4;
25 if (parse_num(&cp, ob)) {
26 bad_line:
27 return error("malformed diff output: %s", line);
28 }
29 if (*cp == ',') {
30 cp++;
31 if (parse_num(&cp, on))
32 goto bad_line;
33 }
34 else
35 *on = 1;
36 if (*cp++ != ' ' || *cp++ != '+')
37 goto bad_line;
38 if (parse_num(&cp, nb))
39 goto bad_line;
40 if (*cp == ',') {
41 cp++;
42 if (parse_num(&cp, nn))
43 goto bad_line;
44 }
45 else
46 *nn = 1;
47 return -!!memcmp(cp, " @@", 3);
48 }
49
50 static void consume_one(void *priv_, char *s, unsigned long size)
51 {
52 struct xdiff_emit_state *priv = priv_;
53 char *ep;
54 while (size) {
55 unsigned long this_size;
56 ep = memchr(s, '\n', size);
57 this_size = (ep == NULL) ? size : (ep - s + 1);
58 priv->consume(priv, s, this_size);
59 size -= this_size;
60 s += this_size;
61 }
62 }
63
64 int xdiff_outf(void *priv_, mmbuffer_t *mb, int nbuf)
65 {
66 struct xdiff_emit_state *priv = priv_;
67 int i;
68
69 for (i = 0; i < nbuf; i++) {
70 if (mb[i].ptr[mb[i].size-1] != '\n') {
71 /* Incomplete line */
72 priv->remainder = xrealloc(priv->remainder,
73 priv->remainder_size +
74 mb[i].size);
75 memcpy(priv->remainder + priv->remainder_size,
76 mb[i].ptr, mb[i].size);
77 priv->remainder_size += mb[i].size;
78 continue;
79 }
80
81 /* we have a complete line */
82 if (!priv->remainder) {
83 consume_one(priv, mb[i].ptr, mb[i].size);
84 continue;
85 }
86 priv->remainder = xrealloc(priv->remainder,
87 priv->remainder_size +
88 mb[i].size);
89 memcpy(priv->remainder + priv->remainder_size,
90 mb[i].ptr, mb[i].size);
91 consume_one(priv, priv->remainder,
92 priv->remainder_size + mb[i].size);
93 free(priv->remainder);
94 priv->remainder = NULL;
95 priv->remainder_size = 0;
96 }
97 if (priv->remainder) {
98 consume_one(priv, priv->remainder, priv->remainder_size);
99 free(priv->remainder);
100 priv->remainder = NULL;
101 priv->remainder_size = 0;
102 }
103 return 0;
104 }
105
106 /*
107 * Trim down common substring at the end of the buffers,
108 * but leave at least ctx lines at the end.
109 */
110 static void trim_common_tail(mmfile_t *a, mmfile_t *b, long ctx)
111 {
112 const int blk = 1024;
113 long trimmed = 0, recovered = 0;
114 char *ap = a->ptr + a->size;
115 char *bp = b->ptr + b->size;
116 long smaller = (a->size < b->size) ? a->size : b->size;
117
118 while (blk + trimmed <= smaller && !memcmp(ap - blk, bp - blk, blk)) {
119 trimmed += blk;
120 ap -= blk;
121 bp -= blk;
122 }
123
124 while (recovered < trimmed && ctx)
125 if (ap[recovered++] == '\n')
126 ctx--;
127 a->size -= (trimmed - recovered);
128 b->size -= (trimmed - recovered);
129 }
130
131 int xdi_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, xdemitconf_t const *xecfg, xdemitcb_t *xecb)
132 {
133 mmfile_t a = *mf1;
134 mmfile_t b = *mf2;
135
136 trim_common_tail(&a, &b, xecfg->ctxlen);
137
138 return xdl_diff(&a, &b, xpp, xecfg, xecb);
139 }
140
141 int read_mmfile(mmfile_t *ptr, const char *filename)
142 {
143 struct stat st;
144 FILE *f;
145 size_t sz;
146
147 if (stat(filename, &st))
148 return error("Could not stat %s", filename);
149 if ((f = fopen(filename, "rb")) == NULL)
150 return error("Could not open %s", filename);
151 sz = xsize_t(st.st_size);
152 ptr->ptr = xmalloc(sz);
153 if (fread(ptr->ptr, sz, 1, f) != 1)
154 return error("Could not read %s", filename);
155 fclose(f);
156 ptr->size = sz;
157 return 0;
158 }
159
160 #define FIRST_FEW_BYTES 8000
161 int buffer_is_binary(const char *ptr, unsigned long size)
162 {
163 if (FIRST_FEW_BYTES < size)
164 size = FIRST_FEW_BYTES;
165 return !!memchr(ptr, 0, size);
166 }
167
168 struct ff_regs {
169 int nr;
170 struct ff_reg {
171 regex_t re;
172 int negate;
173 } *array;
174 };
175
176 static long ff_regexp(const char *line, long len,
177 char *buffer, long buffer_size, void *priv)
178 {
179 char *line_buffer = xstrndup(line, len); /* make NUL terminated */
180 struct ff_regs *regs = priv;
181 regmatch_t pmatch[2];
182 int result = 0, i;
183
184 for (i = 0; i < regs->nr; i++) {
185 struct ff_reg *reg = regs->array + i;
186 if (reg->negate ^ !!regexec(&reg->re,
187 line_buffer, 2, pmatch, 0)) {
188 free(line_buffer);
189 return -1;
190 }
191 }
192 i = pmatch[1].rm_so >= 0 ? 1 : 0;
193 line += pmatch[i].rm_so;
194 result = pmatch[i].rm_eo - pmatch[i].rm_so;
195 if (result > buffer_size)
196 result = buffer_size;
197 else
198 while (result > 0 && (isspace(line[result - 1]) ||
199 line[result - 1] == '\n'))
200 result--;
201 memcpy(buffer, line, result);
202 free(line_buffer);
203 return result;
204 }
205
206 void xdiff_set_find_func(xdemitconf_t *xecfg, const char *value)
207 {
208 int i;
209 struct ff_regs *regs;
210
211 xecfg->find_func = ff_regexp;
212 regs = xecfg->find_func_priv = xmalloc(sizeof(struct ff_regs));
213 for (i = 0, regs->nr = 1; value[i]; i++)
214 if (value[i] == '\n')
215 regs->nr++;
216 regs->array = xmalloc(regs->nr * sizeof(struct ff_reg));
217 for (i = 0; i < regs->nr; i++) {
218 struct ff_reg *reg = regs->array + i;
219 const char *ep = strchr(value, '\n'), *expression;
220 char *buffer = NULL;
221
222 reg->negate = (*value == '!');
223 if (reg->negate && i == regs->nr - 1)
224 die("Last expression must not be negated: %s", value);
225 if (*value == '!')
226 value++;
227 if (ep)
228 expression = buffer = xstrndup(value, ep - value);
229 else
230 expression = value;
231 if (regcomp(&reg->re, expression, 0))
232 die("Invalid regexp to look for hunk header: %s", expression);
233 if (buffer)
234 free(buffer);
235 value = ep + 1;
236 }
237 }