examples/diff.c

   1 /*
   2  * libgit2 "diff" example - shows how to use the diff 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 the use of the libgit2 diff APIs to
  19  * create `git_diff` objects and display them, emulating a number of
  20  * core Git `diff` command line options.
  21  *
  22  * This covers on a portion of the core Git diff options and doesn't
  23  * have particularly good error handling, but it should show most of
  24  * the core libgit2 diff APIs, including various types of diffs and
  25  * how to do renaming detection and patch formatting.
  26  */
  27
  28 static const char *colors[] = {
  29         "\033[m", /* reset */
  30         "\033[1m", /* bold */
  31         "\033[31m", /* red */
  32         "\033[32m", /* green */
  33         "\033[36m" /* cyan */
  34 };
  35
  36 /** The 'opts' struct captures all the various parsed command line options. */
  37 struct opts {
  38         git_diff_options diffopts;
  39         git_diff_find_options findopts;
  40         int color;
  41         int cached;
  42         git_diff_format_t format;
  43         const char *treeish1;
  44         const char *treeish2;
  45         const char *dir;
  46 };
  47
  48 /** These functions are implemented at the end */
  49 static void parse_opts(struct opts *o, int argc, char *argv[]);
  50 static int color_printer(
  51         const git_diff_delta*, const git_diff_hunk*, const git_diff_line*, void*);
  52
  53 int main(int argc, char *argv[])
  54 {
  55         git_repository *repo = NULL;
  56         git_tree *t1 = NULL, *t2 = NULL;
  57         git_diff *diff;
  58         struct opts o = {
  59                 GIT_DIFF_OPTIONS_INIT, GIT_DIFF_FIND_OPTIONS_INIT,
  60                 -1, 0, GIT_DIFF_FORMAT_PATCH, NULL, NULL, "."
  61         };
  62
  63         git_threads_init();
  64
  65         parse_opts(&o, argc, argv);
  66
  67         check_lg2(git_repository_open_ext(&repo, o.dir, 0, NULL),
  68                 "Could not open repository", o.dir);
  69
  70         /**
  71          * Possible argument patterns:
  72          *
  73          *  * &lt;sha1&gt; &lt;sha2&gt;
  74          *  * &lt;sha1&gt; --cached
  75          *  * &lt;sha1&gt;
  76          *  * --cached
  77          *  * nothing
  78          *
  79          * Currently ranged arguments like &lt;sha1&gt;..&lt;sha2&gt; and &lt;sha1&gt;...&lt;sha2&gt;
  80          * are not supported in this example
  81          */
  82
  83         if (o.treeish1)
  84                 treeish_to_tree(&t1, repo, o.treeish1);
  85         if (o.treeish2)
  86                 treeish_to_tree(&t2, repo, o.treeish2);
  87
  88         if (t1 && t2)
  89                 check_lg2(
  90                         git_diff_tree_to_tree(&diff, repo, t1, t2, &o.diffopts),
  91                         "diff trees", NULL);
  92         else if (t1 && o.cached)
  93                 check_lg2(
  94                         git_diff_tree_to_index(&diff, repo, t1, NULL, &o.diffopts),
  95                         "diff tree to index", NULL);
  96         else if (t1)
  97                 check_lg2(
  98                         git_diff_tree_to_workdir_with_index(&diff, repo, t1, &o.diffopts),
  99                         "diff tree to working directory", NULL);
 100         else if (o.cached) {
 101                 treeish_to_tree(&t1, repo, "HEAD");
 102                 check_lg2(
 103                         git_diff_tree_to_index(&diff, repo, t1, NULL, &o.diffopts),
 104                         "diff tree to index", NULL);
 105         }
 106         else
 107                 check_lg2(
 108                         git_diff_index_to_workdir(&diff, repo, NULL, &o.diffopts),
 109                         "diff index to working directory", NULL);
 110
 111         /** Apply rename and copy detection if requested. */
 112
 113         if ((o.findopts.flags & GIT_DIFF_FIND_ALL) != 0)
 114                 check_lg2(
 115                         git_diff_find_similar(diff, &o.findopts),
 116                         "finding renames and copies", NULL);
 117
 118         /** Generate simple output using libgit2 display helper. */
 119
 120         if (o.color >= 0)
 121                 fputs(colors[0], stdout);
 122
 123         check_lg2(
 124                 git_diff_print(diff, o.format, color_printer, &o.color),
 125                 "displaying diff", NULL);
 126
 127         if (o.color >= 0)
 128                 fputs(colors[0], stdout);
 129
 130         /** Cleanup before exiting. */
 131
 132         git_diff_free(diff);
 133         git_tree_free(t1);
 134         git_tree_free(t2);
 135         git_repository_free(repo);
 136
 137         git_threads_shutdown();
 138
 139         return 0;
 140 }
 141
 142 static void usage(const char *message, const char *arg)
 143 {
 144         if (message && arg)
 145                 fprintf(stderr, "%s: %s\n", message, arg);
 146         else if (message)
 147                 fprintf(stderr, "%s\n", message);
 148         fprintf(stderr, "usage: diff [<tree-oid> [<tree-oid>]]\n");
 149         exit(1);
 150 }
 151
 152 /** This implements very rudimentary colorized output. */
 153 static int color_printer(
 154         const git_diff_delta *delta,
 155         const git_diff_hunk *hunk,
 156         const git_diff_line *line,
 157         void *data)
 158 {
 159         int *last_color = data, color = 0;
 160
 161         (void)delta; (void)hunk;
 162
 163         if (*last_color >= 0) {
 164                 switch (line->origin) {
 165                 case GIT_DIFF_LINE_ADDITION:  color = 3; break;
 166                 case GIT_DIFF_LINE_DELETION:  color = 2; break;
 167                 case GIT_DIFF_LINE_ADD_EOFNL: color = 3; break;
 168                 case GIT_DIFF_LINE_DEL_EOFNL: color = 2; break;
 169                 case GIT_DIFF_LINE_FILE_HDR:  color = 1; break;
 170                 case GIT_DIFF_LINE_HUNK_HDR:  color = 4; break;
 171                 default: break;
 172                 }
 173
 174                 if (color != *last_color) {
 175                         if (*last_color == 1 || color == 1)
 176                                 fputs(colors[0], stdout);
 177                         fputs(colors[color], stdout);
 178                         *last_color = color;
 179                 }
 180         }
 181
 182         return diff_output(delta, hunk, line, stdout);
 183 }
 184
 185 /** Parse arguments as copied from git-diff. */
 186 static void parse_opts(struct opts *o, int argc, char *argv[])
 187 {
 188         struct args_info args = ARGS_INFO_INIT;
 189
 190
 191         for (args.pos = 1; args.pos < argc; ++args.pos) {
 192                 const char *a = argv[args.pos];
 193
 194                 if (a[0] != '-') {
 195                         if (o->treeish1 == NULL)
 196                                 o->treeish1 = a;
 197                         else if (o->treeish2 == NULL)
 198                                 o->treeish2 = a;
 199                         else
 200                                 usage("Only one or two tree identifiers can be provided", NULL);
 201                 }
 202                 else if (!strcmp(a, "-p") || !strcmp(a, "-u") ||
 203                         !strcmp(a, "--patch"))
 204                         o->format = GIT_DIFF_FORMAT_PATCH;
 205                 else if (!strcmp(a, "--cached"))
 206                         o->cached = 1;
 207                 else if (!strcmp(a, "--name-only"))
 208                         o->format = GIT_DIFF_FORMAT_NAME_ONLY;
 209                 else if (!strcmp(a, "--name-status"))
 210                         o->format = GIT_DIFF_FORMAT_NAME_STATUS;
 211                 else if (!strcmp(a, "--raw"))
 212                         o->format = GIT_DIFF_FORMAT_RAW;
 213                 else if (!strcmp(a, "--color"))
 214                         o->color = 0;
 215                 else if (!strcmp(a, "--no-color"))
 216                         o->color = -1;
 217                 else if (!strcmp(a, "-R"))
 218                         o->diffopts.flags |= GIT_DIFF_REVERSE;
 219                 else if (!strcmp(a, "-a") || !strcmp(a, "--text"))
 220                         o->diffopts.flags |= GIT_DIFF_FORCE_TEXT;
 221                 else if (!strcmp(a, "--ignore-space-at-eol"))
 222                         o->diffopts.flags |= GIT_DIFF_IGNORE_WHITESPACE_EOL;
 223                 else if (!strcmp(a, "-b") || !strcmp(a, "--ignore-space-change"))
 224                         o->diffopts.flags |= GIT_DIFF_IGNORE_WHITESPACE_CHANGE;
 225                 else if (!strcmp(a, "-w") || !strcmp(a, "--ignore-all-space"))
 226                         o->diffopts.flags |= GIT_DIFF_IGNORE_WHITESPACE;
 227                 else if (!strcmp(a, "--ignored"))
 228                         o->diffopts.flags |= GIT_DIFF_INCLUDE_IGNORED;
 229                 else if (!strcmp(a, "--untracked"))
 230                         o->diffopts.flags |= GIT_DIFF_INCLUDE_UNTRACKED;
 231                 else if (match_uint16_arg(
 232                                 &o->findopts.rename_threshold, &args, "-M") ||
 233                         match_uint16_arg(
 234                                 &o->findopts.rename_threshold, &args, "--find-renames"))
 235                         o->findopts.flags |= GIT_DIFF_FIND_RENAMES;
 236                 else if (match_uint16_arg(
 237                                 &o->findopts.copy_threshold, &args, "-C") ||
 238                         match_uint16_arg(
 239                                 &o->findopts.copy_threshold, &args, "--find-copies"))
 240                         o->findopts.flags |= GIT_DIFF_FIND_COPIES;
 241                 else if (!strcmp(a, "--find-copies-harder"))
 242                         o->findopts.flags |= GIT_DIFF_FIND_COPIES_FROM_UNMODIFIED;
 243                 else if (is_prefixed(a, "-B") || is_prefixed(a, "--break-rewrites"))
 244                         /* TODO: parse thresholds */
 245                         o->findopts.flags |= GIT_DIFF_FIND_REWRITES;
 246                 else if (!match_uint16_arg(
 247                                 &o->diffopts.context_lines, &args, "-U") &&
 248                         !match_uint16_arg(
 249                                 &o->diffopts.context_lines, &args, "--unified") &&
 250                         !match_uint16_arg(
 251                                 &o->diffopts.interhunk_lines, &args, "--inter-hunk-context") &&
 252                         !match_str_arg(&o->diffopts.old_prefix, &args, "--src-prefix") &&
 253                         !match_str_arg(&o->diffopts.new_prefix, &args, "--dst-prefix") &&
 254                         !match_str_arg(&o->dir, &args, "--git-dir"))
 255                         usage("Unknown command line argument", a);
 256         }
 257 }