examples/diff.c

   1 /*
   2  * Copyright (C) the libgit2 contributors. All rights reserved.
   3  *
   4  * This file is part of libgit2, distributed under the GNU GPL v2 with
   5  * a Linking Exception. For full terms see the included COPYING file.
   6  */
   7
   8 #include "common.h"
   9
  10 /**
  11  * This example demonstrates the use of the libgit2 diff APIs to
  12  * create `git_diff` objects and display them, emulating a number of
  13  * core Git `diff` command line options.
  14  *
  15  * This covers on a portion of the core Git diff options and doesn't
  16  * have particularly good error handling, but it should show most of
  17  * the core libgit2 diff APIs, including various types of diffs and
  18  * how to do renaming detection and patch formatting.
  19  */
  20
  21 static const char *colors[] = {
  22         "\033[m", /* reset */
  23         "\033[1m", /* bold */
  24         "\033[31m", /* red */
  25         "\033[32m", /* green */
  26         "\033[36m" /* cyan */
  27 };
  28
  29 /** The 'opts' struct captures all the various parsed command line options. */
  30 struct opts {
  31         git_diff_options diffopts;
  32         git_diff_find_options findopts;
  33         int color;
  34         int cached;
  35         git_diff_format_t format;
  36         const char *treeish1;
  37         const char *treeish2;
  38         const char *dir;
  39 };
  40
  41 /** These functions are implemented at the end */
  42 static void parse_opts(struct opts *o, int argc, char *argv[]);
  43 static int color_printer(
  44         const git_diff_delta*, const git_diff_hunk*, const git_diff_line*, void*);
  45
  46 int main(int argc, char *argv[])
  47 {
  48         git_repository *repo = NULL;
  49         git_tree *t1 = NULL, *t2 = NULL;
  50         git_diff *diff;
  51         struct opts o = {
  52                 GIT_DIFF_OPTIONS_INIT, GIT_DIFF_FIND_OPTIONS_INIT,
  53                 -1, 0, GIT_DIFF_FORMAT_PATCH, NULL, NULL, "."
  54         };
  55
  56         git_threads_init();
  57
  58         parse_opts(&o, argc, argv);
  59
  60         check_lg2(git_repository_open_ext(&repo, o.dir, 0, NULL),
  61                 "Could not open repository", o.dir);
  62
  63         /**
  64          * Possible argument patterns:
  65          *
  66          *  * &lt;sha1&gt; &lt;sha2&gt;
  67          *  * &lt;sha1&gt; --cached
  68          *  * &lt;sha1&gt;
  69          *  * --cached
  70          *  * nothing
  71          *
  72          * Currently ranged arguments like &lt;sha1&gt;..&lt;sha2&gt; and &lt;sha1&gt;...&lt;sha2&gt;
  73          * are not supported in this example
  74          */
  75
  76         if (o.treeish1)
  77                 treeish_to_tree(&t1, repo, o.treeish1);
  78         if (o.treeish2)
  79                 treeish_to_tree(&t2, repo, o.treeish2);
  80
  81         if (t1 && t2)
  82                 check_lg2(
  83                         git_diff_tree_to_tree(&diff, repo, t1, t2, &o.diffopts),
  84                         "diff trees", NULL);
  85         else if (t1 && o.cached)
  86                 check_lg2(
  87                         git_diff_tree_to_index(&diff, repo, t1, NULL, &o.diffopts),
  88                         "diff tree to index", NULL);
  89         else if (t1)
  90                 check_lg2(
  91                         git_diff_tree_to_workdir_with_index(&diff, repo, t1, &o.diffopts),
  92                         "diff tree to working directory", NULL);
  93         else if (o.cached) {
  94                 treeish_to_tree(&t1, repo, "HEAD");
  95                 check_lg2(
  96                         git_diff_tree_to_index(&diff, repo, t1, NULL, &o.diffopts),
  97                         "diff tree to index", NULL);
  98         }
  99         else
 100                 check_lg2(
 101                         git_diff_index_to_workdir(&diff, repo, NULL, &o.diffopts),
 102                         "diff index to working directory", NULL);
 103
 104         /** Apply rename and copy detection if requested. */
 105
 106         if ((o.findopts.flags & GIT_DIFF_FIND_ALL) != 0)
 107                 check_lg2(
 108                         git_diff_find_similar(diff, &o.findopts),
 109                         "finding renames and copies", NULL);
 110
 111         /** Generate simple output using libgit2 display helper. */
 112
 113         if (o.color >= 0)
 114                 fputs(colors[0], stdout);
 115
 116         check_lg2(
 117                 git_diff_print(diff, o.format, color_printer, &o.color),
 118                 "displaying diff", NULL);
 119
 120         if (o.color >= 0)
 121                 fputs(colors[0], stdout);
 122
 123         /** Cleanup before exiting. */
 124
 125         git_diff_free(diff);
 126         git_tree_free(t1);
 127         git_tree_free(t2);
 128         git_repository_free(repo);
 129
 130         git_threads_shutdown();
 131
 132         return 0;
 133 }
 134
 135 static void usage(const char *message, const char *arg)
 136 {
 137         if (message && arg)
 138                 fprintf(stderr, "%s: %s\n", message, arg);
 139         else if (message)
 140                 fprintf(stderr, "%s\n", message);
 141         fprintf(stderr, "usage: diff [<tree-oid> [<tree-oid>]]\n");
 142         exit(1);
 143 }
 144
 145 /** This implements very rudimentary colorized output. */
 146 static int color_printer(
 147         const git_diff_delta *delta,
 148         const git_diff_hunk *hunk,
 149         const git_diff_line *line,
 150         void *data)
 151 {
 152         int *last_color = data, color = 0;
 153
 154         (void)delta; (void)hunk;
 155
 156         if (*last_color >= 0) {
 157                 switch (line->origin) {
 158                 case GIT_DIFF_LINE_ADDITION:  color = 3; break;
 159                 case GIT_DIFF_LINE_DELETION:  color = 2; break;
 160                 case GIT_DIFF_LINE_ADD_EOFNL: color = 3; break;
 161                 case GIT_DIFF_LINE_DEL_EOFNL: color = 2; break;
 162                 case GIT_DIFF_LINE_FILE_HDR:  color = 1; break;
 163                 case GIT_DIFF_LINE_HUNK_HDR:  color = 4; break;
 164                 default: break;
 165                 }
 166
 167                 if (color != *last_color) {
 168                         if (*last_color == 1 || color == 1)
 169                                 fputs(colors[0], stdout);
 170                         fputs(colors[color], stdout);
 171                         *last_color = color;
 172                 }
 173         }
 174
 175         return diff_output(delta, hunk, line, stdout);
 176 }
 177
 178 /** Parse arguments as copied from git-diff. */
 179 static void parse_opts(struct opts *o, int argc, char *argv[])
 180 {
 181         struct args_info args = ARGS_INFO_INIT;
 182
 183
 184         for (args.pos = 1; args.pos < argc; ++args.pos) {
 185                 const char *a = argv[args.pos];
 186
 187                 if (a[0] != '-') {
 188                         if (o->treeish1 == NULL)
 189                                 o->treeish1 = a;
 190                         else if (o->treeish2 == NULL)
 191                                 o->treeish2 = a;
 192                         else
 193                                 usage("Only one or two tree identifiers can be provided", NULL);
 194                 }
 195                 else if (!strcmp(a, "-p") || !strcmp(a, "-u") ||
 196                         !strcmp(a, "--patch"))
 197                         o->format = GIT_DIFF_FORMAT_PATCH;
 198                 else if (!strcmp(a, "--cached"))
 199                         o->cached = 1;
 200                 else if (!strcmp(a, "--name-only"))
 201                         o->format = GIT_DIFF_FORMAT_NAME_ONLY;
 202                 else if (!strcmp(a, "--name-status"))
 203                         o->format = GIT_DIFF_FORMAT_NAME_STATUS;
 204                 else if (!strcmp(a, "--raw"))
 205                         o->format = GIT_DIFF_FORMAT_RAW;
 206                 else if (!strcmp(a, "--color"))
 207                         o->color = 0;
 208                 else if (!strcmp(a, "--no-color"))
 209                         o->color = -1;
 210                 else if (!strcmp(a, "-R"))
 211                         o->diffopts.flags |= GIT_DIFF_REVERSE;
 212                 else if (!strcmp(a, "-a") || !strcmp(a, "--text"))
 213                         o->diffopts.flags |= GIT_DIFF_FORCE_TEXT;
 214                 else if (!strcmp(a, "--ignore-space-at-eol"))
 215                         o->diffopts.flags |= GIT_DIFF_IGNORE_WHITESPACE_EOL;
 216                 else if (!strcmp(a, "-b") || !strcmp(a, "--ignore-space-change"))
 217                         o->diffopts.flags |= GIT_DIFF_IGNORE_WHITESPACE_CHANGE;
 218                 else if (!strcmp(a, "-w") || !strcmp(a, "--ignore-all-space"))
 219                         o->diffopts.flags |= GIT_DIFF_IGNORE_WHITESPACE;
 220                 else if (!strcmp(a, "--ignored"))
 221                         o->diffopts.flags |= GIT_DIFF_INCLUDE_IGNORED;
 222                 else if (!strcmp(a, "--untracked"))
 223                         o->diffopts.flags |= GIT_DIFF_INCLUDE_UNTRACKED;
 224                 else if (match_uint16_arg(
 225                                 &o->findopts.rename_threshold, &args, "-M") ||
 226                         match_uint16_arg(
 227                                 &o->findopts.rename_threshold, &args, "--find-renames"))
 228                         o->findopts.flags |= GIT_DIFF_FIND_RENAMES;
 229                 else if (match_uint16_arg(
 230                                 &o->findopts.copy_threshold, &args, "-C") ||
 231                         match_uint16_arg(
 232                                 &o->findopts.copy_threshold, &args, "--find-copies"))
 233                         o->findopts.flags |= GIT_DIFF_FIND_COPIES;
 234                 else if (!strcmp(a, "--find-copies-harder"))
 235                         o->findopts.flags |= GIT_DIFF_FIND_COPIES_FROM_UNMODIFIED;
 236                 else if (is_prefixed(a, "-B") || is_prefixed(a, "--break-rewrites"))
 237                         /* TODO: parse thresholds */
 238                         o->findopts.flags |= GIT_DIFF_FIND_REWRITES;
 239                 else if (!match_uint16_arg(
 240                                 &o->diffopts.context_lines, &args, "-U") &&
 241                         !match_uint16_arg(
 242                                 &o->diffopts.context_lines, &args, "--unified") &&
 243                         !match_uint16_arg(
 244                                 &o->diffopts.interhunk_lines, &args, "--inter-hunk-context") &&
 245                         !match_str_arg(&o->diffopts.old_prefix, &args, "--src-prefix") &&
 246                         !match_str_arg(&o->diffopts.new_prefix, &args, "--dst-prefix") &&
 247                         !match_str_arg(&o->dir, &args, "--git-dir"))
 248                         usage("Unknown command line argument", a);
 249         }
 250 }