examples/blame.c

   1 /*
   2  * libgit2 "blame" example - shows how to use the blame API
   3  *
   4  * Written by the libgit2 contributors
   5  *
   6  * To the extent possible under law, the author(s) have dedicated all copyright
   7  * and related and neighboring rights to this software to the public domain
   8  * worldwide. This software is distributed without any warranty.
   9  *
  10  * You should have received a copy of the CC0 Public Domain Dedication along
  11  * with this software. If not, see
  12  * <http://creativecommons.org/publicdomain/zero/1.0/>.
  13  */
  14
  15 #include "common.h"
  16
  17 /**
  18  * This example demonstrates how to invoke the libgit2 blame API to roughly
  19  * simulate the output of `git blame` and a few of its command line arguments.
  20  */
  21
  22 struct blame_opts {
  23         char *path;
  24         char *commitspec;
  25         int C;
  26         int M;
  27         int start_line;
  28         int end_line;
  29         int F;
  30 };
  31 static void parse_opts(struct blame_opts *o, int argc, char *argv[]);
  32
  33 int lg2_blame(git_repository *repo, int argc, char *argv[])
  34 {
  35         int line, break_on_null_hunk;
  36         git_object_size_t i, rawsize;
  37         char spec[1024] = {0};
  38         struct blame_opts o = {0};
  39         const char *rawdata;
  40         git_revspec revspec = {0};
  41         git_blame_options blameopts = GIT_BLAME_OPTIONS_INIT;
  42         git_blame *blame = NULL;
  43         git_blob *blob;
  44         git_object *obj;
  45
  46         parse_opts(&o, argc, argv);
  47         if (o.M) blameopts.flags |= GIT_BLAME_TRACK_COPIES_SAME_COMMIT_MOVES;
  48         if (o.C) blameopts.flags |= GIT_BLAME_TRACK_COPIES_SAME_COMMIT_COPIES;
  49         if (o.F) blameopts.flags |= GIT_BLAME_FIRST_PARENT;
  50
  51         /**
  52          * The commit range comes in "committish" form. Use the rev-parse API to
  53          * nail down the end points.
  54          */
  55         if (o.commitspec) {
  56                 check_lg2(git_revparse(&revspec, repo, o.commitspec), "Couldn't parse commit spec", NULL);
  57                 if (revspec.flags & GIT_REVSPEC_SINGLE) {
  58                         git_oid_cpy(&blameopts.newest_commit, git_object_id(revspec.from));
  59                         git_object_free(revspec.from);
  60                 } else {
  61                         git_oid_cpy(&blameopts.oldest_commit, git_object_id(revspec.from));
  62                         git_oid_cpy(&blameopts.newest_commit, git_object_id(revspec.to));
  63                         git_object_free(revspec.from);
  64                         git_object_free(revspec.to);
  65                 }
  66         }
  67
  68         /** Run the blame. */
  69         check_lg2(git_blame_file(&blame, repo, o.path, &blameopts), "Blame error", NULL);
  70
  71         /**
  72          * Get the raw data inside the blob for output. We use the
  73          * `committish:path/to/file.txt` format to find it.
  74          */
  75         if (git_oid_is_zero(&blameopts.newest_commit))
  76                 strcpy(spec, "HEAD");
  77         else
  78                 git_oid_tostr(spec, sizeof(spec), &blameopts.newest_commit);
  79         strcat(spec, ":");
  80         strcat(spec, o.path);
  81
  82         check_lg2(git_revparse_single(&obj, repo, spec), "Object lookup error", NULL);
  83         check_lg2(git_blob_lookup(&blob, repo, git_object_id(obj)), "Blob lookup error", NULL);
  84         git_object_free(obj);
  85
  86         rawdata = git_blob_rawcontent(blob);
  87         rawsize = git_blob_rawsize(blob);
  88
  89         /** Produce the output. */
  90         line = 1;
  91         i = 0;
  92         break_on_null_hunk = 0;
  93         while (i < rawsize) {
  94                 const char *eol = memchr(rawdata + i, '\n', (size_t)(rawsize - i));
  95                 char oid[10] = {0};
  96                 const git_blame_hunk *hunk = git_blame_get_hunk_byline(blame, line);
  97
  98                 if (break_on_null_hunk && !hunk)
  99                         break;
 100
 101                 if (hunk) {
 102                         char sig[128] = {0};
 103                         break_on_null_hunk = 1;
 104
 105                         git_oid_tostr(oid, 10, &hunk->final_commit_id);
 106                         snprintf(sig, 30, "%s <%s>", hunk->final_signature->name, hunk->final_signature->email);
 107
 108                         printf("%s ( %-30s %3d) %.*s\n",
 109                                         oid,
 110                                         sig,
 111                                         line,
 112                                         (int)(eol - rawdata - i),
 113                                         rawdata + i);
 114                 }
 115
 116                 i = (int)(eol - rawdata + 1);
 117                 line++;
 118         }
 119
 120         /** Cleanup. */
 121         git_blob_free(blob);
 122         git_blame_free(blame);
 123
 124         return 0;
 125 }
 126
 127 /** Tell the user how to make this thing work. */
 128 static void usage(const char *msg, const char *arg)
 129 {
 130         if (msg && arg)
 131                 fprintf(stderr, "%s: %s\n", msg, arg);
 132         else if (msg)
 133                 fprintf(stderr, "%s\n", msg);
 134         fprintf(stderr, "usage: blame [options] [<commit range>] <path>\n");
 135         fprintf(stderr, "\n");
 136         fprintf(stderr, "   <commit range>      example: `HEAD~10..HEAD`, or `1234abcd`\n");
 137         fprintf(stderr, "   -L <n,m>            process only line range n-m, counting from 1\n");
 138         fprintf(stderr, "   -M                  find line moves within and across files\n");
 139         fprintf(stderr, "   -C                  find line copies within and across files\n");
 140         fprintf(stderr, "   -F                  follow only the first parent commits\n");
 141         fprintf(stderr, "\n");
 142         exit(1);
 143 }
 144
 145 /** Parse the arguments. */
 146 static void parse_opts(struct blame_opts *o, int argc, char *argv[])
 147 {
 148         int i;
 149         char *bare_args[3] = {0};
 150
 151         if (argc < 2) usage(NULL, NULL);
 152
 153         for (i=1; i<argc; i++) {
 154                 char *a = argv[i];
 155
 156                 if (a[0] != '-') {
 157                         int i=0;
 158                         while (bare_args[i] && i < 3) ++i;
 159                         if (i >= 3)
 160                                 usage("Invalid argument set", NULL);
 161                         bare_args[i] = a;
 162                 }
 163                 else if (!strcmp(a, "--"))
 164                         continue;
 165                 else if (!strcasecmp(a, "-M"))
 166                         o->M = 1;
 167                 else if (!strcasecmp(a, "-C"))
 168                         o->C = 1;
 169                 else if (!strcasecmp(a, "-F"))
 170                         o->F = 1;
 171                 else if (!strcasecmp(a, "-L")) {
 172                         i++; a = argv[i];
 173                         if (i >= argc) fatal("Not enough arguments to -L", NULL);
 174                         check_lg2(sscanf(a, "%d,%d", &o->start_line, &o->end_line)-2, "-L format error", NULL);
 175                 }
 176                 else {
 177                         /* commit range */
 178                         if (o->commitspec) fatal("Only one commit spec allowed", NULL);
 179                         o->commitspec = a;
 180                 }
 181         }
 182
 183         /* Handle the bare arguments */
 184         if (!bare_args[0]) usage("Please specify a path", NULL);
 185         o->path = bare_args[0];
 186         if (bare_args[1]) {
 187                 /* <commitspec> <path> */
 188                 o->path = bare_args[1];
 189                 o->commitspec = bare_args[0];
 190         }
 191         if (bare_args[2]) {
 192                 /* <oldcommit> <newcommit> <path> */
 193                 char spec[128] = {0};
 194                 o->path = bare_args[2];
 195                 sprintf(spec, "%s..%s", bare_args[0], bare_args[1]);
 196                 o->commitspec = spec;
 197         }
 198 }