aboutsummaryrefslogtreecommitdiff
path: root/show-diff.c
blob: 8a66e59cf5f6e05dd5944e479f95a2a12a6ccf95 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
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
212
/*
 * GIT - The information manager from hell
 *
 * Copyright (C) Linus Torvalds, 2005
 */
#include "cache.h"

static char *diff_cmd = "diff -L '%s' -u -N  - '%s'";

/* Help to copy the thing properly quoted for the shell safety.
 * any single quote is replaced with '\'', and the caller is
 * expected to enclose the result within a single quote pair.
 *
 * E.g.
 *  original     sq_expand     result
 *  name     ==> name      ==> 'name'
 *  a b      ==> a b       ==> 'a b'
 *  a'b      ==> a'\''b    ==> 'a'\''b'
 *
 * NOTE! The returned memory belongs to this function so
 * do not free it.
 */
static char *sq_expand(char *src)
{
	static char *buf = NULL;
	static int buf_size = -1;
	int cnt, c;
	char *cp;

	/* count single quote characters */ 
	for (cnt = 0, cp = src; *cp; cnt++, cp++)
		if (*cp == '\'')
			cnt += 3;

	if (buf_size < cnt) {
		free(buf);
		buf_size = cnt;
		buf = malloc(cnt);
	}

	cp = buf;
	while ((c = *src++)) {
		if (c != '\'')
			*cp++ = c;
		else {
			cp = strcpy(cp, "'\\''");
			cp += 4;
		}
	}
	*cp = 0;
	return buf;
}

static void show_differences(char *name, void *old_contents,
			     unsigned long long old_size)
{
	FILE *f;
	static char *cmd = NULL;
	static int cmd_size = -1;

	char *name_sq = sq_expand(name);
	int cmd_required_length = strlen(name_sq) * 2 + strlen(diff_cmd);

	if (cmd_size < cmd_required_length) {
		free(cmd);
		cmd_size = cmd_required_length;
		cmd = malloc(cmd_required_length);
	}
	snprintf(cmd, cmd_size, diff_cmd, name_sq, name_sq);
	f = popen(cmd, "w");
	if (old_size)
		fwrite(old_contents, old_size, 1, f);
	pclose(f);
}

static void show_diff_empty(struct cache_entry *ce)
{
	char *old;
	unsigned long int size;
	int lines=0;
	unsigned char type[20], *p, *end;

	old = read_sha1_file(ce->sha1, type, &size);
	if (size > 0) {
		int startline = 1;
		int c = 0;

		printf("--- %s\n", ce->name);
		printf("+++ /dev/null\n");
		p = old;
		end = old + size;
		while (p < end)
			if (*p++ == '\n')
				lines ++;
		printf("@@ -1,%d +0,0 @@\n", lines);
		p = old;
		while (p < end) {
			c = *p++;
			if (startline) {
				putchar('-');
				startline = 0;
			}
			putchar(c);
			if (c == '\n')
				startline = 1;
		}
		if (c!='\n')
			printf("\n");
		fflush(stdout);
	}
}

static const char *show_diff_usage = "show-diff [-q] [-s] [-z] [paths...]";

static int matches_pathspec(struct cache_entry *ce, char **spec, int cnt)
{
	int i;
	int namelen = ce_namelen(ce);
	for (i = 0; i < cnt; i++) {
		int speclen = strlen(spec[i]);
		if (! strncmp(spec[i], ce->name, speclen) &&
		    speclen <= namelen &&
		    (ce->name[speclen] == 0 ||
		     ce->name[speclen] == '/'))
			return 1;
	}
	return 0;
}

int main(int argc, char **argv)
{
	int silent = 0;
	int silent_on_nonexisting_files = 0;
	int machine_readable = 0;
	int entries = read_cache();
	int i;

	while (1 < argc && argv[1][0] == '-') {
		if (!strcmp(argv[1], "-s"))
			silent_on_nonexisting_files = silent = 1;
		else if (!strcmp(argv[1], "-q"))
			silent_on_nonexisting_files = 1;
		else if (!strcmp(argv[1], "-z"))
			machine_readable = 1;
		else
			usage(show_diff_usage);
		argv++; argc--;
	}

	/* At this point, if argc == 1, then we are doing everything.
	 * Otherwise argv[1] .. argv[argc-1] have the explicit paths.
	 */
	if (entries < 0) {
		perror("read_cache");
		exit(1);
	}
	for (i = 0; i < entries; i++) {
		struct stat st;
		struct cache_entry *ce = active_cache[i];
		int changed;
		unsigned long size;
		char type[20];
		void *old;

		if (1 < argc &&
		    ! matches_pathspec(ce, argv+1, argc-1))
			continue;

		if (ce_stage(ce)) {
			if (machine_readable)
				printf("U %s%c", ce->name, 0);
			else
				printf("%s: Unmerged\n",
				       ce->name);
			while (i < entries &&
			       !strcmp(ce->name, active_cache[i]->name))
				i++;
			i--; /* compensate for loop control increments */
			continue;
		}
 
		if (stat(ce->name, &st) < 0) {
			if (errno == ENOENT && silent_on_nonexisting_files)
				continue;
			if (machine_readable)
				printf("X %s%c", ce->name, 0);
			else {
				printf("%s: %s\n", ce->name, strerror(errno));
				if (errno == ENOENT)
					show_diff_empty(ce);
			}
			continue;
		}
		changed = cache_match_stat(ce, &st);
		if (!changed)
			continue;
		if (!machine_readable)
			printf("%s: %s\n", ce->name, sha1_to_hex(ce->sha1));
		else {
			printf("%s %s%c", sha1_to_hex(ce->sha1), ce->name, 0);
			continue;
		}
		fflush(stdout);
		if (silent)
			continue;

		old = read_sha1_file(ce->sha1, type, &size);
		show_differences(ce->name, old, size);
		free(old);
	}
	return 0;
}