short circuit out of a few places where we would allocate zero bytes
[git/git.git] / diffcore-order.c
CommitLineData
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1/*
2 * Copyright (C) 2005 Junio C Hamano
3 */
4#include "cache.h"
5#include "diff.h"
6#include "diffcore.h"
7#include <fnmatch.h>
8
9static char **order;
10static int order_cnt;
11
12static void prepare_order(const char *orderfile)
13{
14 int fd, cnt, pass;
15 void *map;
16 char *cp, *endp;
17 struct stat st;
18
19 if (order)
20 return;
21
22 fd = open(orderfile, O_RDONLY);
23 if (fd < 0)
24 return;
25 if (fstat(fd, &st)) {
26 close(fd);
27 return;
28 }
29 map = mmap(NULL, st.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
30 close(fd);
e35f9824 31 if (map == MAP_FAILED)
af5323e0
JH
32 return;
33 endp = map + st.st_size;
34 for (pass = 0; pass < 2; pass++) {
35 cnt = 0;
36 cp = map;
37 while (cp < endp) {
38 char *ep;
39 for (ep = cp; ep < endp && *ep != '\n'; ep++)
40 ;
41 /* cp to ep has one line */
42 if (*cp == '\n' || *cp == '#')
43 ; /* comment */
44 else if (pass == 0)
45 cnt++;
46 else {
47 if (*ep == '\n') {
48 *ep = 0;
49 order[cnt] = cp;
50 }
51 else {
52 order[cnt] = xmalloc(ep-cp+1);
53 memcpy(order[cnt], cp, ep-cp);
54 order[cnt][ep-cp] = 0;
55 }
56 cnt++;
57 }
58 if (ep < endp)
59 ep++;
60 cp = ep;
61 }
62 if (pass == 0) {
63 order_cnt = cnt;
64 order = xmalloc(sizeof(*order) * cnt);
65 }
66 }
67}
68
69struct pair_order {
70 struct diff_filepair *pair;
71 int orig_order;
72 int order;
73};
74
75static int match_order(const char *path)
76{
77 int i;
78 char p[PATH_MAX];
79
80 for (i = 0; i < order_cnt; i++) {
81 strcpy(p, path);
82 while (p[0]) {
83 char *cp;
84 if (!fnmatch(order[i], p, 0))
85 return i;
86 cp = strrchr(p, '/');
87 if (!cp)
88 break;
89 *cp = 0;
90 }
91 }
92 return order_cnt;
93}
94
95static int compare_pair_order(const void *a_, const void *b_)
96{
97 struct pair_order const *a, *b;
98 a = (struct pair_order const *)a_;
99 b = (struct pair_order const *)b_;
100 if (a->order != b->order)
101 return a->order - b->order;
102 return a->orig_order - b->orig_order;
103}
104
105void diffcore_order(const char *orderfile)
106{
107 struct diff_queue_struct *q = &diff_queued_diff;
108 struct pair_order *o = xmalloc(sizeof(*o) * q->nr);
109 int i;
110
111 prepare_order(orderfile);
112 for (i = 0; i < q->nr; i++) {
113 o[i].pair = q->queue[i];
114 o[i].orig_order = i;
115 o[i].order = match_order(o[i].pair->two->path);
116 }
117 qsort(o, q->nr, sizeof(*o), compare_pair_order);
118 for (i = 0; i < q->nr; i++)
119 q->queue[i] = o[i].pair;
120 free(o);
121 return;
122}