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
|
/*
* GIT - The information manager from hell
*
* Copyright (C) Linus Torvalds, 2005
*/
#include "cache.h"
static int stage = 0;
static int read_one_entry(unsigned char *sha1, const char *base, int baselen, const char *pathname, unsigned mode)
{
int len = strlen(pathname);
unsigned int size = cache_entry_size(baselen + len);
struct cache_entry *ce = malloc(size);
memset(ce, 0, size);
ce->ce_mode = htonl(mode);
ce->ce_flags = create_ce_flags(baselen + len, stage);
memcpy(ce->name, base, baselen);
memcpy(ce->name + baselen, pathname, len+1);
memcpy(ce->sha1, sha1, 20);
return add_cache_entry(ce, 1);
}
static int read_tree(unsigned char *sha1, const char *base, int baselen)
{
void *buffer;
unsigned long size;
char type[20];
buffer = read_sha1_file(sha1, type, &size);
if (!buffer)
return -1;
if (strcmp(type, "tree"))
return -1;
while (size) {
int len = strlen(buffer)+1;
unsigned char *sha1 = buffer + len;
char *path = strchr(buffer, ' ')+1;
unsigned int mode;
if (size < len + 20 || sscanf(buffer, "%o", &mode) != 1)
return -1;
buffer = sha1 + 20;
size -= len + 20;
if (S_ISDIR(mode)) {
int retval;
int pathlen = strlen(path);
char *newbase = malloc(baselen + 1 + pathlen);
memcpy(newbase, base, baselen);
memcpy(newbase + baselen, path, pathlen);
newbase[baselen + pathlen] = '/';
retval = read_tree(sha1, newbase, baselen + pathlen + 1);
free(newbase);
if (retval)
return -1;
continue;
}
if (read_one_entry(sha1, base, baselen, path, mode) < 0)
return -1;
}
return 0;
}
static int remove_lock = 0;
static void remove_lock_file(void)
{
if (remove_lock)
unlink(".git/index.lock");
}
/*
* This removes all identical entries and collapses them to state 0.
*
* _Any_ other merge (even a trivial one, like both ) is left to user policy.
* That includes "both created the same file", and "both removed the same
* file" - which are trivial, but the user might still want to _note_ it.
*/
static int same_entry(struct cache_entry *a,
struct cache_entry *b,
struct cache_entry *c)
{
int len = ce_namelen(a);
return a->ce_mode == b->ce_mode &&
a->ce_mode == c->ce_mode &&
ce_namelen(b) == len &&
ce_namelen(c) == len &&
!memcmp(a->name, b->name, len) &&
!memcmp(a->name, c->name, len) &&
!memcmp(a->sha1, b->sha1, 20) &&
!memcmp(a->sha1, c->sha1, 20);
}
static void trivially_merge_cache(struct cache_entry **src, int nr)
{
struct cache_entry **dst = src;
while (nr) {
struct cache_entry *ce;
ce = src[0];
if (nr > 2 && same_entry(ce, src[1], src[2])) {
ce->ce_flags &= ~htons(CE_STAGEMASK);
src += 2;
nr -= 2;
active_nr -= 2;
}
*dst = ce;
src++;
dst++;
nr--;
}
}
int main(int argc, char **argv)
{
int i, newfd;
unsigned char sha1[20];
newfd = open(".git/index.lock", O_RDWR | O_CREAT | O_EXCL, 0600);
if (newfd < 0)
die("unable to create new cachefile");
atexit(remove_lock_file);
remove_lock = 1;
for (i = 1; i < argc; i++) {
const char *arg = argv[i];
/* "-m" stands for "merge", meaning we start in stage 1 */
if (!strcmp(arg, "-m")) {
stage = 1;
continue;
}
if (get_sha1_hex(arg, sha1) < 0)
usage("read-tree [-m] <sha1>");
if (stage > 3)
usage("can't merge more than two trees");
if (read_tree(sha1, "", 0) < 0)
die("failed to unpack tree object %s", arg);
stage++;
}
if (stage == 4)
trivially_merge_cache(active_cache, active_nr);
if (write_cache(newfd, active_cache, active_nr) ||
rename(".git/index.lock", ".git/index"))
die("unable to write new index file");
remove_lock = 0;
return 0;
}
|
