builtin/patch-id.c

   1 #include "builtin.h"
   2
   3 static void flush_current_id(int patchlen, unsigned char *id, unsigned char *result)
   4 {
   5         char name[50];
   6
   7         if (!patchlen)
   8                 return;
   9
  10         memcpy(name, sha1_to_hex(id), 41);
  11         printf("%s %s\n", sha1_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(unsigned char *result, git_SHA_CTX *ctx)
  57 {
  58         unsigned char hash[20];
  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 < 20; ++i) {
  66                 carry += result[i] + hash[i];
  67                 result[i] = carry;
  68                 carry >>= 8;
  69         }
  70 }
  71
  72 static int get_one_patchid(unsigned char *next_sha1, unsigned char *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         hashclr(result);
  81
  82         while (strbuf_getwholeline(line_buf, stdin, '\n') != EOF) {
  83                 char *line = line_buf->buf;
  84                 char *p = line;
  85                 int len;
  86
  87                 if (!memcmp(line, "diff-tree ", 10))
  88                         p += 10;
  89                 else if (!memcmp(line, "commit ", 7))
  90                         p += 7;
  91                 else if (!memcmp(line, "From ", 5))
  92                         p += 5;
  93                 else if (!memcmp(line, "\\ ", 2) && 12 < strlen(line))
  94                         continue;
  95
  96                 if (!get_sha1_hex(p, next_sha1)) {
  97                         found_next = 1;
  98                         break;
  99                 }
 100
 101                 /* Ignore commit comments */
 102                 if (!patchlen && memcmp(line, "diff ", 5))
 103                         continue;
 104
 105                 /* Parsing diff header?  */
 106                 if (before == -1) {
 107                         if (!memcmp(line, "index ", 6))
 108                                 continue;
 109                         else if (!memcmp(line, "--- ", 4))
 110                                 before = after = 1;
 111                         else if (!isalpha(line[0]))
 112                                 break;
 113                 }
 114
 115                 /* Looking for a valid hunk header?  */
 116                 if (before == 0 && after == 0) {
 117                         if (!memcmp(line, "@@ -", 4)) {
 118                                 /* Parse next hunk, but ignore line numbers.  */
 119                                 scan_hunk_header(line, &before, &after);
 120                                 continue;
 121                         }
 122
 123                         /* Split at the end of the patch.  */
 124                         if (memcmp(line, "diff ", 5))
 125                                 break;
 126
 127                         /* Else we're parsing another header.  */
 128                         if (stable)
 129                                 flush_one_hunk(result, &ctx);
 130                         before = after = -1;
 131                 }
 132
 133                 /* If we get here, we're inside a hunk.  */
 134                 if (line[0] == '-' || line[0] == ' ')
 135                         before--;
 136                 if (line[0] == '+' || line[0] == ' ')
 137                         after--;
 138
 139                 /* Compute the sha without whitespace */
 140                 len = remove_space(line);
 141                 patchlen += len;
 142                 git_SHA1_Update(&ctx, line, len);
 143         }
 144
 145         if (!found_next)
 146                 hashclr(next_sha1);
 147
 148         flush_one_hunk(result, &ctx);
 149
 150         return patchlen;
 151 }
 152
 153 static void generate_id_list(int stable)
 154 {
 155         unsigned char sha1[20], n[20], result[20];
 156         int patchlen;
 157         struct strbuf line_buf = STRBUF_INIT;
 158
 159         hashclr(sha1);
 160         while (!feof(stdin)) {
 161                 patchlen = get_one_patchid(n, result, &line_buf, stable);
 162                 flush_current_id(patchlen, sha1, result);
 163                 hashcpy(sha1, n);
 164         }
 165         strbuf_release(&line_buf);
 166 }
 167
 168 static const char patch_id_usage[] = "git patch-id [--stable | --unstable] < patch";
 169
 170 static int git_patch_id_config(const char *var, const char *value, void *cb)
 171 {
 172         int *stable = cb;
 173
 174         if (!strcmp(var, "patchid.stable")) {
 175                 *stable = git_config_bool(var, value);
 176                 return 0;
 177         }
 178
 179         return git_default_config(var, value, cb);
 180 }
 181
 182 int cmd_patch_id(int argc, const char **argv, const char *prefix)
 183 {
 184         int stable = -1;
 185
 186         git_config(git_patch_id_config, &stable);
 187
 188         /* If nothing is set, default to unstable. */
 189         if (stable < 0)
 190                 stable = 0;
 191
 192         if (argc == 2 && !strcmp(argv[1], "--stable"))
 193                 stable = 1;
 194         else if (argc == 2 && !strcmp(argv[1], "--unstable"))
 195                 stable = 0;
 196         else if (argc != 1)
 197                 usage(patch_id_usage);
 198
 199         generate_id_list(stable);
 200         return 0;
 201 }