patch-ids.con commit t/lib-diff-alternative: abstract away SHA-1-specific constants (d29d500)
   1#include "cache.h"
   2#include "diff.h"
   3#include "commit.h"
   4#include "sha1-lookup.h"
   5#include "patch-ids.h"
   6
   7static int patch_id_defined(struct commit *commit)
   8{
   9        /* must be 0 or 1 parents */
  10        return !commit->parents || !commit->parents->next;
  11}
  12
  13int 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 */
  38static int patch_id_cmp(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 oidcmp(&a->patch_id, &b->patch_id);
  57}
  58
  59int init_patch_ids(struct patch_ids *ids)
  60{
  61        memset(ids, 0, sizeof(*ids));
  62        diff_setup(&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_cmp, &ids->diffopts, 256);
  67        return 0;
  68}
  69
  70int free_patch_ids(struct patch_ids *ids)
  71{
  72        hashmap_free(&ids->patches, 1);
  73        return 0;
  74}
  75
  76static 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
  90struct 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
 105struct 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}