cherry-pick/revert: make usage say '<commit-ish>...'
[git] / builtin / patch-id.c
1 #include "builtin.h"
2
3 static void flush_current_id(int patchlen, unsigned char *id, git_SHA_CTX *c)
4 {
5         unsigned char result[20];
6         char name[50];
7
8         if (!patchlen)
9                 return;
10
11         git_SHA1_Final(result, c);
12         memcpy(name, sha1_to_hex(id), 41);
13         printf("%s %s\n", sha1_to_hex(result), name);
14         git_SHA1_Init(c);
15 }
16
17 static int remove_space(char *line)
18 {
19         char *src = line;
20         char *dst = line;
21         unsigned char c;
22
23         while ((c = *src++) != '\0') {
24                 if (!isspace(c))
25                         *dst++ = c;
26         }
27         return dst - line;
28 }
29
30 static int scan_hunk_header(const char *p, int *p_before, int *p_after)
31 {
32         static const char digits[] = "0123456789";
33         const char *q, *r;
34         int n;
35
36         q = p + 4;
37         n = strspn(q, digits);
38         if (q[n] == ',') {
39                 q += n + 1;
40                 n = strspn(q, digits);
41         }
42         if (n == 0 || q[n] != ' ' || q[n+1] != '+')
43                 return 0;
44
45         r = q + n + 2;
46         n = strspn(r, digits);
47         if (r[n] == ',') {
48                 r += n + 1;
49                 n = strspn(r, digits);
50         }
51         if (n == 0)
52                 return 0;
53
54         *p_before = atoi(q);
55         *p_after = atoi(r);
56         return 1;
57 }
58
59 static int get_one_patchid(unsigned char *next_sha1, git_SHA_CTX *ctx, struct strbuf *line_buf)
60 {
61         int patchlen = 0, found_next = 0;
62         int before = -1, after = -1;
63
64         while (strbuf_getwholeline(line_buf, stdin, '\n') != EOF) {
65                 char *line = line_buf->buf;
66                 char *p = line;
67                 int len;
68
69                 if (!memcmp(line, "diff-tree ", 10))
70                         p += 10;
71                 else if (!memcmp(line, "commit ", 7))
72                         p += 7;
73                 else if (!memcmp(line, "From ", 5))
74                         p += 5;
75                 else if (!memcmp(line, "\\ ", 2) && 12 < strlen(line))
76                         continue;
77
78                 if (!get_sha1_hex(p, next_sha1)) {
79                         found_next = 1;
80                         break;
81                 }
82
83                 /* Ignore commit comments */
84                 if (!patchlen && memcmp(line, "diff ", 5))
85                         continue;
86
87                 /* Parsing diff header?  */
88                 if (before == -1) {
89                         if (!memcmp(line, "index ", 6))
90                                 continue;
91                         else if (!memcmp(line, "--- ", 4))
92                                 before = after = 1;
93                         else if (!isalpha(line[0]))
94                                 break;
95                 }
96
97                 /* Looking for a valid hunk header?  */
98                 if (before == 0 && after == 0) {
99                         if (!memcmp(line, "@@ -", 4)) {
100                                 /* Parse next hunk, but ignore line numbers.  */
101                                 scan_hunk_header(line, &before, &after);
102                                 continue;
103                         }
104
105                         /* Split at the end of the patch.  */
106                         if (memcmp(line, "diff ", 5))
107                                 break;
108
109                         /* Else we're parsing another header.  */
110                         before = after = -1;
111                 }
112
113                 /* If we get here, we're inside a hunk.  */
114                 if (line[0] == '-' || line[0] == ' ')
115                         before--;
116                 if (line[0] == '+' || line[0] == ' ')
117                         after--;
118
119                 /* Compute the sha without whitespace */
120                 len = remove_space(line);
121                 patchlen += len;
122                 git_SHA1_Update(ctx, line, len);
123         }
124
125         if (!found_next)
126                 hashclr(next_sha1);
127
128         return patchlen;
129 }
130
131 static void generate_id_list(void)
132 {
133         unsigned char sha1[20], n[20];
134         git_SHA_CTX ctx;
135         int patchlen;
136         struct strbuf line_buf = STRBUF_INIT;
137
138         git_SHA1_Init(&ctx);
139         hashclr(sha1);
140         while (!feof(stdin)) {
141                 patchlen = get_one_patchid(n, &ctx, &line_buf);
142                 flush_current_id(patchlen, sha1, &ctx);
143                 hashcpy(sha1, n);
144         }
145         strbuf_release(&line_buf);
146 }
147
148 static const char patch_id_usage[] = "git patch-id < patch";
149
150 int cmd_patch_id(int argc, const char **argv, const char *prefix)
151 {
152         if (argc != 1)
153                 usage(patch_id_usage);
154
155         generate_id_list();
156         return 0;
157 }