| 1 | /* |
| 2 | * alloc.c - specialized allocator for internal objects |
| 3 | * |
| 4 | * Copyright (C) 2006 Linus Torvalds |
| 5 | * |
| 6 | * The standard malloc/free wastes too much space for objects, partly because |
| 7 | * it maintains all the allocation infrastructure, but even more because it ends |
| 8 | * up with maximal alignment because it doesn't know what the object alignment |
| 9 | * for the new allocation is. |
| 10 | */ |
| 11 | #include "git-compat-util.h" |
| 12 | #include "object.h" |
| 13 | #include "blob.h" |
| 14 | #include "tree.h" |
| 15 | #include "commit.h" |
| 16 | #include "repository.h" |
| 17 | #include "tag.h" |
| 18 | #include "alloc.h" |
| 19 | |
| 20 | #define BLOCKING 1024 |
| 21 | |
| 22 | union any_object { |
| 23 | struct object object; |
| 24 | struct blob blob; |
| 25 | struct tree tree; |
| 26 | struct commit commit; |
| 27 | struct tag tag; |
| 28 | }; |
| 29 | |
| 30 | struct alloc_state { |
| 31 | int nr; /* number of nodes left in current allocation */ |
| 32 | void *p; /* first free node in current allocation */ |
| 33 | |
| 34 | /* bookkeeping of allocations */ |
| 35 | void **slabs; |
| 36 | int slab_nr, slab_alloc; |
| 37 | }; |
| 38 | |
| 39 | struct alloc_state *alloc_state_alloc(void) |
| 40 | { |
| 41 | return xcalloc(1, sizeof(struct alloc_state)); |
| 42 | } |
| 43 | |
| 44 | void alloc_state_free_and_null(struct alloc_state **s_) |
| 45 | { |
| 46 | struct alloc_state *s = *s_; |
| 47 | |
| 48 | if (!s) |
| 49 | return; |
| 50 | |
| 51 | while (s->slab_nr > 0) { |
| 52 | s->slab_nr--; |
| 53 | free(s->slabs[s->slab_nr]); |
| 54 | } |
| 55 | |
| 56 | FREE_AND_NULL(s->slabs); |
| 57 | FREE_AND_NULL(*s_); |
| 58 | } |
| 59 | |
| 60 | static inline void *alloc_node(struct alloc_state *s, size_t node_size) |
| 61 | { |
| 62 | void *ret; |
| 63 | |
| 64 | if (!s->nr) { |
| 65 | s->nr = BLOCKING; |
| 66 | s->p = xmalloc(BLOCKING * node_size); |
| 67 | |
| 68 | ALLOC_GROW(s->slabs, s->slab_nr + 1, s->slab_alloc); |
| 69 | s->slabs[s->slab_nr++] = s->p; |
| 70 | } |
| 71 | s->nr--; |
| 72 | ret = s->p; |
| 73 | s->p = (char *)s->p + node_size; |
| 74 | memset(ret, 0, node_size); |
| 75 | |
| 76 | return ret; |
| 77 | } |
| 78 | |
| 79 | void *alloc_blob_node(struct repository *r) |
| 80 | { |
| 81 | struct blob *b = alloc_node(r->parsed_objects->blob_state, sizeof(struct blob)); |
| 82 | b->object.type = OBJ_BLOB; |
| 83 | return b; |
| 84 | } |
| 85 | |
| 86 | void *alloc_tree_node(struct repository *r) |
| 87 | { |
| 88 | struct tree *t = alloc_node(r->parsed_objects->tree_state, sizeof(struct tree)); |
| 89 | t->object.type = OBJ_TREE; |
| 90 | return t; |
| 91 | } |
| 92 | |
| 93 | void *alloc_tag_node(struct repository *r) |
| 94 | { |
| 95 | struct tag *t = alloc_node(r->parsed_objects->tag_state, sizeof(struct tag)); |
| 96 | t->object.type = OBJ_TAG; |
| 97 | return t; |
| 98 | } |
| 99 | |
| 100 | void *alloc_object_node(struct repository *r) |
| 101 | { |
| 102 | struct object *obj = alloc_node(r->parsed_objects->object_state, sizeof(union any_object)); |
| 103 | obj->type = OBJ_NONE; |
| 104 | return obj; |
| 105 | } |
| 106 | |
| 107 | /* |
| 108 | * The returned count is to be used as an index into commit slabs, |
| 109 | * that are *NOT* maintained per repository, and that is why a single |
| 110 | * global counter is used. |
| 111 | */ |
| 112 | static unsigned int alloc_commit_index(void) |
| 113 | { |
| 114 | static unsigned int parsed_commits_count; |
| 115 | return parsed_commits_count++; |
| 116 | } |
| 117 | |
| 118 | void init_commit_node(struct commit *c) |
| 119 | { |
| 120 | c->object.type = OBJ_COMMIT; |
| 121 | c->index = alloc_commit_index(); |
| 122 | } |
| 123 | |
| 124 | void *alloc_commit_node(struct repository *r) |
| 125 | { |
| 126 | struct commit *c = alloc_node(r->parsed_objects->commit_state, sizeof(struct commit)); |
| 127 | init_commit_node(c); |
| 128 | return c; |
| 129 | } |