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Commit | Line | Data |
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be3cfa85 JH |
1 | /* |
2 | * Copyright (C) 2005 Junio C Hamano | |
3 | */ | |
4 | #include <sys/types.h> | |
5 | #include <sys/wait.h> | |
86436c28 JH |
6 | #include "cache.h" |
7 | #include "diff.h" | |
8 | ||
be3cfa85 JH |
9 | static char *diff_cmd = "diff -L'k/%s' -L'l/%s'"; |
10 | static char *diff_opts = "-pu"; | |
86436c28 | 11 | |
be3cfa85 | 12 | static const char *external_diff(void) |
86436c28 | 13 | { |
be3cfa85 JH |
14 | static char *external_diff_cmd = NULL; |
15 | static int done_preparing = 0; | |
16 | ||
17 | if (done_preparing) | |
18 | return external_diff_cmd; | |
19 | ||
86436c28 JH |
20 | /* |
21 | * Default values above are meant to match the | |
22 | * Linux kernel development style. Examples of | |
23 | * alternative styles you can specify via environment | |
24 | * variables are: | |
25 | * | |
26 | * GIT_DIFF_CMD="diff -L '%s' -L '%s'" | |
27 | * GIT_DIFF_OPTS="-c"; | |
28 | */ | |
be3cfa85 JH |
29 | if (getenv("GIT_EXTERNAL_DIFF")) |
30 | external_diff_cmd = getenv("GIT_EXTERNAL_DIFF"); | |
31 | ||
32 | /* In case external diff fails... */ | |
86436c28 JH |
33 | diff_cmd = getenv("GIT_DIFF_CMD") ? : diff_cmd; |
34 | diff_opts = getenv("GIT_DIFF_OPTS") ? : diff_opts; | |
be3cfa85 JH |
35 | |
36 | done_preparing = 1; | |
37 | return external_diff_cmd; | |
86436c28 JH |
38 | } |
39 | ||
40 | /* Help to copy the thing properly quoted for the shell safety. | |
41 | * any single quote is replaced with '\'', and the caller is | |
42 | * expected to enclose the result within a single quote pair. | |
43 | * | |
44 | * E.g. | |
45 | * original sq_expand result | |
46 | * name ==> name ==> 'name' | |
47 | * a b ==> a b ==> 'a b' | |
48 | * a'b ==> a'\''b ==> 'a'\''b' | |
49 | */ | |
50 | static char *sq_expand(const char *src) | |
51 | { | |
52 | static char *buf = NULL; | |
53 | int cnt, c; | |
54 | const char *cp; | |
55 | char *bp; | |
56 | ||
57 | /* count bytes needed to store the quoted string. */ | |
58 | for (cnt = 1, cp = src; *cp; cnt++, cp++) | |
59 | if (*cp == '\'') | |
60 | cnt += 3; | |
61 | ||
812666c8 | 62 | buf = xmalloc(cnt); |
86436c28 JH |
63 | bp = buf; |
64 | while ((c = *src++)) { | |
65 | if (c != '\'') | |
66 | *bp++ = c; | |
67 | else { | |
68 | bp = strcpy(bp, "'\\''"); | |
69 | bp += 4; | |
70 | } | |
71 | } | |
72 | *bp = 0; | |
73 | return buf; | |
74 | } | |
75 | ||
be3cfa85 JH |
76 | static struct diff_tempfile { |
77 | const char *name; | |
78 | char hex[41]; | |
79 | char mode[10]; | |
80 | char tmp_path[50]; | |
81 | } diff_temp[2]; | |
82 | ||
83 | static void builtin_diff(const char *name, | |
84 | struct diff_tempfile *temp) | |
86436c28 | 85 | { |
be3cfa85 JH |
86 | static char *diff_arg = "'%s' '%s'"; |
87 | const char *name_1_sq = sq_expand(temp[0].name); | |
88 | const char *name_2_sq = sq_expand(temp[1].name); | |
89 | const char *name_sq = sq_expand(name); | |
90 | ||
91 | /* diff_cmd and diff_arg have 4 %s in total which makes | |
92 | * the sum of these strings 8 bytes larger than required. | |
93 | * we use 2 spaces around diff-opts, and we need to count | |
94 | * terminating NUL, so we subtract 5 here. | |
95 | */ | |
96 | int cmd_size = (strlen(diff_cmd) + | |
97 | strlen(name_sq) * 2 + | |
98 | strlen(diff_opts) + | |
99 | strlen(diff_arg) + | |
100 | strlen(name_1_sq) + strlen(name_2_sq) | |
101 | - 5); | |
812666c8 | 102 | char *cmd = xmalloc(cmd_size); |
be3cfa85 JH |
103 | int next_at = 0; |
104 | ||
105 | next_at += snprintf(cmd+next_at, cmd_size-next_at, | |
106 | diff_cmd, name_sq, name_sq); | |
107 | next_at += snprintf(cmd+next_at, cmd_size-next_at, | |
108 | " %s ", diff_opts); | |
109 | next_at += snprintf(cmd+next_at, cmd_size-next_at, | |
110 | diff_arg, name_1_sq, name_2_sq); | |
111 | execlp("/bin/sh","sh", "-c", cmd, NULL); | |
86436c28 JH |
112 | } |
113 | ||
be3cfa85 JH |
114 | static void prepare_temp_file(const char *name, |
115 | struct diff_tempfile *temp, | |
116 | struct diff_spec *one) | |
86436c28 | 117 | { |
be3cfa85 JH |
118 | static unsigned char null_sha1[20] = { 0, }; |
119 | ||
120 | if (!one->file_valid) { | |
121 | not_a_valid_file: | |
122 | temp->name = "/dev/null"; | |
123 | strcpy(temp->hex, "."); | |
124 | strcpy(temp->mode, "."); | |
86436c28 JH |
125 | return; |
126 | } | |
be3cfa85 JH |
127 | |
128 | if (one->sha1_valid && | |
129 | !memcmp(one->u.sha1, null_sha1, sizeof(null_sha1))) { | |
130 | one->sha1_valid = 0; | |
131 | one->u.name = name; | |
132 | } | |
133 | ||
134 | if (!one->sha1_valid) { | |
135 | struct stat st; | |
136 | temp->name = one->u.name; | |
137 | if (stat(temp->name, &st) < 0) { | |
138 | if (errno == ENOENT) | |
139 | goto not_a_valid_file; | |
140 | die("stat(%s): %s", temp->name, strerror(errno)); | |
141 | } | |
142 | strcpy(temp->hex, "."); | |
143 | sprintf(temp->mode, "%06o", | |
144 | S_IFREG |ce_permissions(st.st_mode)); | |
145 | } | |
146 | else { | |
147 | int fd; | |
148 | void *blob; | |
149 | char type[20]; | |
150 | unsigned long size; | |
151 | ||
152 | blob = read_sha1_file(one->u.sha1, type, &size); | |
153 | if (!blob || strcmp(type, "blob")) | |
154 | die("unable to read blob object for %s (%s)", | |
155 | name, sha1_to_hex(one->u.sha1)); | |
156 | ||
157 | strcpy(temp->tmp_path, ".diff_XXXXXX"); | |
158 | fd = mkstemp(temp->tmp_path); | |
159 | if (fd < 0) | |
160 | die("unable to create temp-file"); | |
161 | if (write(fd, blob, size) != size) | |
162 | die("unable to write temp-file"); | |
163 | close(fd); | |
164 | free(blob); | |
165 | temp->name = temp->tmp_path; | |
166 | strcpy(temp->hex, sha1_to_hex(one->u.sha1)); | |
167 | temp->hex[40] = 0; | |
168 | sprintf(temp->mode, "%06o", one->mode); | |
169 | } | |
170 | } | |
171 | ||
172 | static void remove_tempfile(void) | |
173 | { | |
174 | int i; | |
175 | ||
176 | for (i = 0; i < 2; i++) | |
177 | if (diff_temp[i].name == diff_temp[i].tmp_path) { | |
178 | unlink(diff_temp[i].name); | |
179 | diff_temp[i].name = NULL; | |
180 | } | |
181 | } | |
182 | ||
183 | /* An external diff command takes: | |
184 | * | |
185 | * diff-cmd name infile1 infile1-sha1 infile1-mode \ | |
186 | * infile2 infile2-sha1 infile2-mode. | |
187 | * | |
188 | */ | |
189 | void run_external_diff(const char *name, | |
190 | struct diff_spec *one, | |
191 | struct diff_spec *two) | |
192 | { | |
193 | struct diff_tempfile *temp = diff_temp; | |
194 | int pid, status; | |
195 | static int atexit_asked = 0; | |
196 | ||
197 | prepare_temp_file(name, &temp[0], one); | |
198 | prepare_temp_file(name, &temp[1], two); | |
199 | if (! atexit_asked && | |
200 | (temp[0].name == temp[0].tmp_path || | |
201 | temp[1].name == temp[1].tmp_path)) { | |
202 | atexit_asked = 1; | |
203 | atexit(remove_tempfile); | |
204 | } | |
205 | ||
206 | fflush(NULL); | |
207 | pid = fork(); | |
208 | if (pid < 0) | |
209 | die("unable to fork"); | |
210 | if (!pid) { | |
211 | const char *pgm = external_diff(); | |
212 | if (pgm) | |
213 | execlp(pgm, pgm, | |
214 | name, | |
215 | temp[0].name, temp[0].hex, temp[0].mode, | |
216 | temp[1].name, temp[1].hex, temp[1].mode, | |
217 | NULL); | |
218 | /* | |
219 | * otherwise we use the built-in one. | |
220 | */ | |
221 | builtin_diff(name, temp); | |
222 | exit(0); | |
223 | } | |
224 | if (waitpid(pid, &status, 0) < 0 || !WIFEXITED(status)) | |
225 | die("diff program failed"); | |
226 | ||
227 | remove_tempfile(); | |
228 | } | |
229 | ||
230 | void show_diff_empty(const struct cache_entry *ce, int reverse) | |
231 | { | |
232 | struct diff_spec spec[2], *one, *two; | |
233 | ||
234 | memcpy(spec[0].u.sha1, ce->sha1, 20); | |
235 | spec[0].mode = ntohl(ce->ce_mode); | |
236 | spec[0].sha1_valid = spec[0].file_valid = 1; | |
237 | spec[1].file_valid = 0; | |
238 | ||
239 | if (reverse) { | |
240 | one = spec + 1; two = spec; | |
241 | } else { | |
242 | one = spec; two = one + 1; | |
243 | } | |
244 | ||
245 | run_external_diff(ce->name, one, two); | |
246 | } | |
247 | ||
248 | void show_differences(const struct cache_entry *ce, int reverse) | |
249 | { | |
250 | struct diff_spec spec[2], *one, *two; | |
251 | ||
252 | memcpy(spec[0].u.sha1, ce->sha1, 20); | |
253 | spec[0].mode = ntohl(ce->ce_mode); | |
254 | spec[0].sha1_valid = spec[0].file_valid = 1; | |
255 | ||
256 | spec[1].u.name = ce->name; /* the name we stated */ | |
257 | spec[1].sha1_valid = 0; | |
258 | spec[1].file_valid = 1; | |
259 | ||
260 | if (reverse) { | |
261 | one = spec + 1; two = spec; | |
262 | } else { | |
263 | one = spec; two = one + 1; | |
264 | } | |
265 | ||
266 | run_external_diff(ce->name, one, two); | |
86436c28 | 267 | } |