summaryrefslogtreecommitdiff
path: root/diff-cache.c
blob: 899e37361e5d34a38e4746b3cd290d9b96a6c8f8 (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
#include "cache.h"
#include "diff.h"
 
static int cached_only = 0;
static int generate_patch = 0;
static int line_termination = '\n';
 
/* A file entry went away or appeared */
static void show_file(const char *prefix, struct cache_entry *ce, unsigned char *sha1, unsigned int mode)
{
	if (generate_patch)
		diff_addremove(prefix[0], ntohl(mode), sha1, ce->name, NULL);
	else
		printf("%s%06o\tblob\t%s\t%s%c", prefix, ntohl(mode),
		       sha1_to_hex(sha1), ce->name, line_termination);
}
 
static int get_stat_data(struct cache_entry *ce, unsigned char **sha1p, unsigned int *modep)
{
	unsigned char *sha1 = ce->sha1;
	unsigned int mode = ce->ce_mode;
 
	if (!cached_only) {
		static unsigned char no_sha1[20];
		int changed;
		struct stat st;
		if (stat(ce->name, &st) < 0)
			return -1;
		changed = cache_match_stat(ce, &st);
		if (changed) {
			mode = create_ce_mode(st.st_mode);
			sha1 = no_sha1;
		}
	}
 
	*sha1p = sha1;
	*modep = mode;
	return 0;
}
 
static void show_new_file(struct cache_entry *new)
{
	unsigned char *sha1;
	unsigned int mode;
 
	/* New file in the index: it might actually be different in the working copy */
	if (get_stat_data(new, &sha1, &mode) < 0)
		return;
 
	show_file("+", new, sha1, mode);
}
 
static int show_modified(struct cache_entry *old, struct cache_entry *new)
{
	unsigned int mode, oldmode;
	unsigned char *sha1;
	unsigned char old_sha1_hex[60];
 
	if (get_stat_data(new, &sha1, &mode) < 0) {
		show_file("-", old, old->sha1, old->ce_mode);
		return -1;
	}
 
	oldmode = old->ce_mode;
	if (mode == oldmode && !memcmp(sha1, old->sha1, 20))
		return 0;
 
	mode = ntohl(mode);
	oldmode = ntohl(oldmode);
 
	if (generate_patch)
		diff_change(oldmode, mode,
			    old->sha1, sha1, old->name, NULL);
	else {
		strcpy(old_sha1_hex, sha1_to_hex(old->sha1));
		printf("*%06o->%06o\tblob\t%s->%s\t%s%c", oldmode, mode,
		       old_sha1_hex, sha1_to_hex(sha1),
		       old->name, line_termination);
	}
	return 0;
}
 
static int diff_cache(struct cache_entry **ac, int entries)
{
	while (entries) {
		struct cache_entry *ce = *ac;
		int same = (entries > 1) && same_name(ce, ac[1]);
 
		switch (ce_stage(ce)) {
		case 0:
			/* No stage 1 entry? That means it's a new file */
			if (!same) {
				show_new_file(ce);
				break;
			}
			/* Show difference between old and new */
			show_modified(ac[1], ce);
			break;
		case 1:
			/* No stage 3 (merge) entry? That means it's been deleted */
			if (!same) {
				show_file("-", ce, ce->sha1, ce->ce_mode);
				break;
			}
			/* Otherwise we fall through to the "unmerged" case */
		case 3:
			if (generate_patch)
				diff_unmerge(ce->name);
			else
				printf("U %s%c", ce->name, line_termination);
			break;
 
		default:
			die("impossible cache entry stage");
		}
 
		/*
		 * Ignore all the different stages for this file,
		 * we've handled the relevant cases now.
		 */
		do {
			ac++;
			entries--;
		} while (entries && same_name(ce, ac[0]));
	}
	return 0;
}
 
/*
 * This turns all merge entries into "stage 3". That guarantees that
 * when we read in the new tree (into "stage 1"), we won't lose sight
 * of the fact that we had unmerged entries.
 */
static void mark_merge_entries(void)
{
	int i;
	for (i = 0; i < active_nr; i++) {
		struct cache_entry *ce = active_cache[i];
		if (!ce_stage(ce))
			continue;
		ce->ce_flags |= htons(CE_STAGEMASK);
	}
}
 
static char *diff_cache_usage =
"diff-cache [-r] [-z] [-p] [--cached] <tree sha1>";
 
int main(int argc, char **argv)
{
	unsigned char tree_sha1[20];
	void *tree;
	unsigned long size;
 
	read_cache();
	while (argc > 2) {
		char *arg = argv[1];
		argv++;
		argc--;
		if (!strcmp(arg, "-r")) {
			/* We accept the -r flag just to look like diff-tree */
			continue;
		}
		if (!strcmp(arg, "-p")) {
			generate_patch = 1;
			continue;
		}
		if (!strcmp(arg, "-z")) {
			line_termination = '\0';
			continue;
		}
		if (!strcmp(arg, "--cached")) {
			cached_only = 1;
			continue;
		}
		usage(diff_cache_usage);
	}
 
	if (argc != 2 || get_sha1_hex(argv[1], tree_sha1))
		usage(diff_cache_usage);
 
	mark_merge_entries();
 
	tree = read_object_with_reference(tree_sha1, "tree", &size, 0);
	if (!tree)
		die("bad tree object %s", argv[1]);
	if (read_tree(tree, size, 1))
		die("unable to read tree object %s", argv[1]);
 
	return diff_cache(active_cache, active_nr);
}