Merge branch 'rs/apply-avoid-over-reading' into maint
[git] / builtin / patch-id.c
1 #include "builtin.h"
2
3 static void flush_current_id(int patchlen, struct object_id *id, struct object_id *result)
4 {
5         char name[50];
6
7         if (!patchlen)
8                 return;
9
10         memcpy(name, oid_to_hex(id), GIT_SHA1_HEXSZ + 1);
11         printf("%s %s\n", oid_to_hex(result), name);
12 }
13
14 static int remove_space(char *line)
15 {
16         char *src = line;
17         char *dst = line;
18         unsigned char c;
19
20         while ((c = *src++) != '\0') {
21                 if (!isspace(c))
22                         *dst++ = c;
23         }
24         return dst - line;
25 }
26
27 static int scan_hunk_header(const char *p, int *p_before, int *p_after)
28 {
29         static const char digits[] = "0123456789";
30         const char *q, *r;
31         int n;
32
33         q = p + 4;
34         n = strspn(q, digits);
35         if (q[n] == ',') {
36                 q += n + 1;
37                 n = strspn(q, digits);
38         }
39         if (n == 0 || q[n] != ' ' || q[n+1] != '+')
40                 return 0;
41
42         r = q + n + 2;
43         n = strspn(r, digits);
44         if (r[n] == ',') {
45                 r += n + 1;
46                 n = strspn(r, digits);
47         }
48         if (n == 0)
49                 return 0;
50
51         *p_before = atoi(q);
52         *p_after = atoi(r);
53         return 1;
54 }
55
56 static void flush_one_hunk(struct object_id *result, git_SHA_CTX *ctx)
57 {
58         unsigned char hash[GIT_MAX_RAWSZ];
59         unsigned short carry = 0;
60         int i;
61
62         git_SHA1_Final(hash, ctx);
63         git_SHA1_Init(ctx);
64         /* 20-byte sum, with carry */
65         for (i = 0; i < GIT_SHA1_RAWSZ; ++i) {
66                 carry += result->hash[i] + hash[i];
67                 result->hash[i] = carry;
68                 carry >>= 8;
69         }
70 }
71
72 static int get_one_patchid(struct object_id *next_oid, struct object_id *result,
73                            struct strbuf *line_buf, int stable)
74 {
75         int patchlen = 0, found_next = 0;
76         int before = -1, after = -1;
77         git_SHA_CTX ctx;
78
79         git_SHA1_Init(&ctx);
80         oidclr(result);
81
82         while (strbuf_getwholeline(line_buf, stdin, '\n') != EOF) {
83                 char *line = line_buf->buf;
84                 const char *p = line;
85                 int len;
86
87                 if (!skip_prefix(line, "diff-tree ", &p) &&
88                     !skip_prefix(line, "commit ", &p) &&
89                     !skip_prefix(line, "From ", &p) &&
90                     starts_with(line, "\\ ") && 12 < strlen(line))
91                         continue;
92
93                 if (!get_oid_hex(p, next_oid)) {
94                         found_next = 1;
95                         break;
96                 }
97
98                 /* Ignore commit comments */
99                 if (!patchlen && !starts_with(line, "diff "))
100                         continue;
101
102                 /* Parsing diff header?  */
103                 if (before == -1) {
104                         if (starts_with(line, "index "))
105                                 continue;
106                         else if (starts_with(line, "--- "))
107                                 before = after = 1;
108                         else if (!isalpha(line[0]))
109                                 break;
110                 }
111
112                 /* Looking for a valid hunk header?  */
113                 if (before == 0 && after == 0) {
114                         if (starts_with(line, "@@ -")) {
115                                 /* Parse next hunk, but ignore line numbers.  */
116                                 scan_hunk_header(line, &before, &after);
117                                 continue;
118                         }
119
120                         /* Split at the end of the patch.  */
121                         if (!starts_with(line, "diff "))
122                                 break;
123
124                         /* Else we're parsing another header.  */
125                         if (stable)
126                                 flush_one_hunk(result, &ctx);
127                         before = after = -1;
128                 }
129
130                 /* If we get here, we're inside a hunk.  */
131                 if (line[0] == '-' || line[0] == ' ')
132                         before--;
133                 if (line[0] == '+' || line[0] == ' ')
134                         after--;
135
136                 /* Compute the sha without whitespace */
137                 len = remove_space(line);
138                 patchlen += len;
139                 git_SHA1_Update(&ctx, line, len);
140         }
141
142         if (!found_next)
143                 oidclr(next_oid);
144
145         flush_one_hunk(result, &ctx);
146
147         return patchlen;
148 }
149
150 static void generate_id_list(int stable)
151 {
152         struct object_id oid, n, result;
153         int patchlen;
154         struct strbuf line_buf = STRBUF_INIT;
155
156         oidclr(&oid);
157         while (!feof(stdin)) {
158                 patchlen = get_one_patchid(&n, &result, &line_buf, stable);
159                 flush_current_id(patchlen, &oid, &result);
160                 oidcpy(&oid, &n);
161         }
162         strbuf_release(&line_buf);
163 }
164
165 static const char patch_id_usage[] = "git patch-id [--stable | --unstable]";
166
167 static int git_patch_id_config(const char *var, const char *value, void *cb)
168 {
169         int *stable = cb;
170
171         if (!strcmp(var, "patchid.stable")) {
172                 *stable = git_config_bool(var, value);
173                 return 0;
174         }
175
176         return git_default_config(var, value, cb);
177 }
178
179 int cmd_patch_id(int argc, const char **argv, const char *prefix)
180 {
181         int stable = -1;
182
183         git_config(git_patch_id_config, &stable);
184
185         /* If nothing is set, default to unstable. */
186         if (stable < 0)
187                 stable = 0;
188
189         if (argc == 2 && !strcmp(argv[1], "--stable"))
190                 stable = 1;
191         else if (argc == 2 && !strcmp(argv[1], "--unstable"))
192                 stable = 0;
193         else if (argc != 1)
194                 usage(patch_id_usage);
195
196         generate_id_list(stable);
197         return 0;
198 }