apply: demonstrate a problem applying svn diffs
[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 "cmp" 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_cmp(struct diff_options *opt,
39                         struct patch_id *a,
40                         struct patch_id *b,
41                         const void *unused_keydata)
42 {
43         if (is_null_oid(&a->patch_id) &&
44             commit_patch_id(a->commit, opt, &a->patch_id, 0))
45                 return error("Could not get patch ID for %s",
46                         oid_to_hex(&a->commit->object.oid));
47         if (is_null_oid(&b->patch_id) &&
48             commit_patch_id(b->commit, opt, &b->patch_id, 0))
49                 return error("Could not get patch ID for %s",
50                         oid_to_hex(&b->commit->object.oid));
51         return oidcmp(&a->patch_id, &b->patch_id);
52 }
53
54 int init_patch_ids(struct patch_ids *ids)
55 {
56         memset(ids, 0, sizeof(*ids));
57         diff_setup(&ids->diffopts);
58         ids->diffopts.detect_rename = 0;
59         DIFF_OPT_SET(&ids->diffopts, RECURSIVE);
60         diff_setup_done(&ids->diffopts);
61         hashmap_init(&ids->patches, (hashmap_cmp_fn)patch_id_cmp,
62                      &ids->diffopts, 256);
63         return 0;
64 }
65
66 int free_patch_ids(struct patch_ids *ids)
67 {
68         hashmap_free(&ids->patches, 1);
69         return 0;
70 }
71
72 static int init_patch_id_entry(struct patch_id *patch,
73                                struct commit *commit,
74                                struct patch_ids *ids)
75 {
76         struct object_id header_only_patch_id;
77
78         patch->commit = commit;
79         if (commit_patch_id(commit, &ids->diffopts, &header_only_patch_id, 1))
80                 return -1;
81
82         hashmap_entry_init(patch, sha1hash(header_only_patch_id.hash));
83         return 0;
84 }
85
86 struct patch_id *has_commit_patch_id(struct commit *commit,
87                                      struct patch_ids *ids)
88 {
89         struct patch_id patch;
90
91         if (!patch_id_defined(commit))
92                 return NULL;
93
94         memset(&patch, 0, sizeof(patch));
95         if (init_patch_id_entry(&patch, commit, ids))
96                 return NULL;
97
98         return hashmap_get(&ids->patches, &patch, NULL);
99 }
100
101 struct patch_id *add_commit_patch_id(struct commit *commit,
102                                      struct patch_ids *ids)
103 {
104         struct patch_id *key;
105
106         if (!patch_id_defined(commit))
107                 return NULL;
108
109         key = xcalloc(1, sizeof(*key));
110         if (init_patch_id_entry(key, commit, ids)) {
111                 free(key);
112                 return NULL;
113         }
114
115         hashmap_add(&ids->patches, key);
116         return key;
117 }