Merge branch 'uk/merge-subtree-doc-update'
[git] / patch-ids.c
1 #include "cache.h"
2 #include "diff.h"
3 #include "commit.h"
4 #include "sha1-lookup.h"
5 #include "patch-ids.h"
6
7 static int patch_id_defined(struct commit *commit)
8 {
9         /* must be 0 or 1 parents */
10         return !commit->parents || !commit->parents->next;
11 }
12
13 int commit_patch_id(struct commit *commit, struct diff_options *options,
14                     struct object_id *oid, int diff_header_only)
15 {
16         if (!patch_id_defined(commit))
17                 return -1;
18
19         if (commit->parents)
20                 diff_tree_oid(&commit->parents->item->object.oid,
21                               &commit->object.oid, "", options);
22         else
23                 diff_root_tree_oid(&commit->object.oid, "", options);
24         diffcore_std(options);
25         return diff_flush_patch_id(options, oid, diff_header_only);
26 }
27
28 /*
29  * When we cannot load the full patch-id for both commits for whatever
30  * reason, the function returns -1 (i.e. return error(...)). Despite
31  * the "neq" in the name of this function, the caller only cares about
32  * the return value being zero (a and b are equivalent) or non-zero (a
33  * and b are different), and returning non-zero would keep both in the
34  * result, even if they actually were equivalent, in order to err on
35  * the side of safety.  The actual value being negative does not have
36  * any significance; only that it is non-zero matters.
37  */
38 static int patch_id_neq(const void *cmpfn_data,
39                         const void *entry,
40                         const void *entry_or_key,
41                         const void *unused_keydata)
42 {
43         /* NEEDSWORK: const correctness? */
44         struct diff_options *opt = (void *)cmpfn_data;
45         struct patch_id *a = (void *)entry;
46         struct patch_id *b = (void *)entry_or_key;
47
48         if (is_null_oid(&a->patch_id) &&
49             commit_patch_id(a->commit, opt, &a->patch_id, 0))
50                 return error("Could not get patch ID for %s",
51                         oid_to_hex(&a->commit->object.oid));
52         if (is_null_oid(&b->patch_id) &&
53             commit_patch_id(b->commit, opt, &b->patch_id, 0))
54                 return error("Could not get patch ID for %s",
55                         oid_to_hex(&b->commit->object.oid));
56         return !oideq(&a->patch_id, &b->patch_id);
57 }
58
59 int init_patch_ids(struct repository *r, struct patch_ids *ids)
60 {
61         memset(ids, 0, sizeof(*ids));
62         repo_diff_setup(r, &ids->diffopts);
63         ids->diffopts.detect_rename = 0;
64         ids->diffopts.flags.recursive = 1;
65         diff_setup_done(&ids->diffopts);
66         hashmap_init(&ids->patches, patch_id_neq, &ids->diffopts, 256);
67         return 0;
68 }
69
70 int free_patch_ids(struct patch_ids *ids)
71 {
72         hashmap_free(&ids->patches, 1);
73         return 0;
74 }
75
76 static int init_patch_id_entry(struct patch_id *patch,
77                                struct commit *commit,
78                                struct patch_ids *ids)
79 {
80         struct object_id header_only_patch_id;
81
82         patch->commit = commit;
83         if (commit_patch_id(commit, &ids->diffopts, &header_only_patch_id, 1))
84                 return -1;
85
86         hashmap_entry_init(patch, sha1hash(header_only_patch_id.hash));
87         return 0;
88 }
89
90 struct patch_id *has_commit_patch_id(struct commit *commit,
91                                      struct patch_ids *ids)
92 {
93         struct patch_id patch;
94
95         if (!patch_id_defined(commit))
96                 return NULL;
97
98         memset(&patch, 0, sizeof(patch));
99         if (init_patch_id_entry(&patch, commit, ids))
100                 return NULL;
101
102         return hashmap_get(&ids->patches, &patch, NULL);
103 }
104
105 struct patch_id *add_commit_patch_id(struct commit *commit,
106                                      struct patch_ids *ids)
107 {
108         struct patch_id *key;
109
110         if (!patch_id_defined(commit))
111                 return NULL;
112
113         key = xcalloc(1, sizeof(*key));
114         if (init_patch_id_entry(key, commit, ids)) {
115                 free(key);
116                 return NULL;
117         }
118
119         hashmap_add(&ids->patches, key);
120         return key;
121 }