src/reset.c

   1 /*
   2  * Copyright (C) 2009-2012 the libgit2 contributors
   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 #include "commit.h"
  10 #include "tag.h"
  11 #include "merge.h"
  12 #include "git2/reset.h"
  13 #include "git2/checkout.h"
  14 #include "git2/merge.h"
  15
  16 #define ERROR_MSG "Cannot perform reset"
  17
  18 static int update_head(git_repository *repo, git_object *commit)
  19 {
  20         int error;
  21         git_reference *head = NULL, *target = NULL;
  22
  23         error = git_repository_head(&head, repo);
  24
  25         if (error < 0 && error != GIT_EORPHANEDHEAD)
  26                 return error;
  27
  28         if (error == GIT_EORPHANEDHEAD) {
  29                 giterr_clear();
  30
  31                 /*
  32                  * TODO: This is a bit weak as this doesn't support chained
  33                  * symbolic references. yet.
  34                  */
  35                 if ((error = git_reference_lookup(&head, repo, GIT_HEAD_FILE)) < 0)
  36                         goto cleanup;
  37
  38                 if ((error = git_reference_create(
  39                         &target,
  40                         repo,
  41                         git_reference_symbolic_target(head),
  42                         git_object_id(commit), 0)) < 0)
  43                                 goto cleanup;
  44         } else {
  45                 if ((error = git_reference_set_target(head, git_object_id(commit))) < 0)
  46                         goto cleanup;
  47         }
  48
  49         error = 0;
  50
  51 cleanup:
  52         git_reference_free(head);
  53         git_reference_free(target);
  54         return error;
  55 }
  56
  57 int git_reset(
  58         git_repository *repo,
  59         git_object *target,
  60         git_reset_t reset_type)
  61 {
  62         git_object *commit = NULL;
  63         git_index *index = NULL;
  64         git_tree *tree = NULL;
  65         int error = 0;
  66         git_checkout_opts opts = GIT_CHECKOUT_OPTS_INIT;
  67
  68         assert(repo && target);
  69
  70         if (git_object_owner(target) != repo) {
  71                 giterr_set(GITERR_OBJECT,
  72                         "%s - The given target does not belong to this repository.", ERROR_MSG);
  73                 return -1;
  74         }
  75
  76         if (reset_type != GIT_RESET_SOFT &&
  77                 (error = git_repository__ensure_not_bare(repo,
  78                         reset_type == GIT_RESET_MIXED ? "reset mixed" : "reset hard")) < 0)
  79                 return error;
  80
  81         if ((error = git_object_peel(&commit, target, GIT_OBJ_COMMIT)) < 0 ||
  82                 (error = git_repository_index(&index, repo)) < 0 ||
  83                 (error = git_commit_tree(&tree, (git_commit *)commit)) < 0)
  84                 goto cleanup;
  85
  86         if (reset_type == GIT_RESET_SOFT &&
  87                 (git_repository_state(repo) == GIT_REPOSITORY_STATE_MERGE ||
  88                  git_index_has_conflicts(index)))
  89         {
  90                 giterr_set(GITERR_OBJECT, "%s (soft) in the middle of a merge.", ERROR_MSG);
  91                 error = GIT_EUNMERGED;
  92                 goto cleanup;
  93         }
  94
  95         /* move HEAD to the new target */
  96         if ((error = update_head(repo, commit)) < 0)
  97                 goto cleanup;
  98
  99         if (reset_type == GIT_RESET_HARD) {
 100                 /* overwrite working directory with HEAD */
 101                 opts.checkout_strategy = GIT_CHECKOUT_FORCE;
 102
 103                 if ((error = git_checkout_tree(repo, (git_object *)tree, &opts)) < 0)
 104                         goto cleanup;
 105         }
 106
 107         if (reset_type > GIT_RESET_SOFT) {
 108                 /* reset index to the target content */
 109
 110                 if ((error = git_repository_index(&index, repo)) < 0 ||
 111                         (error = git_index_read_tree(index, tree)) < 0 ||
 112                         (error = git_index_write(index)) < 0)
 113                         goto cleanup;
 114
 115                 if ((error = git_repository_merge_cleanup(repo)) < 0) {
 116                         giterr_set(GITERR_INDEX, "%s - failed to clean up merge data", ERROR_MSG);
 117                         goto cleanup;
 118                 }
 119         }
 120
 121 cleanup:
 122         git_object_free(commit);
 123         git_index_free(index);
 124         git_tree_free(tree);
 125
 126         return error;
 127 }