]> git.ipfire.org Git - thirdparty/git.git/blobdiff - pack-objects.h
Merge remote-tracking branch 'git-po/maint'
[thirdparty/git.git] / pack-objects.h
index b4a83a6123941cd512298eed5e221e6c0f03a822..edf74dabddfdb2b67bad803d1c898e93a3af4d8b 100644 (file)
@@ -1,7 +1,39 @@
 #ifndef PACK_OBJECTS_H
 #define PACK_OBJECTS_H
 
+#include "object-store.h"
+
+#define DEFAULT_DELTA_CACHE_SIZE (256 * 1024 * 1024)
+
+#define OE_DFS_STATE_BITS      2
+#define OE_DEPTH_BITS          12
+#define OE_IN_PACK_BITS                10
+#define OE_Z_DELTA_BITS                20
+/*
+ * Note that oe_set_size() becomes expensive when the given size is
+ * above this limit. Don't lower it too much.
+ */
+#define OE_SIZE_BITS           31
+#define OE_DELTA_SIZE_BITS     20
+
+/*
+ * State flags for depth-first search used for analyzing delta cycles.
+ *
+ * The depth is measured in delta-links to the base (so if A is a delta
+ * against B, then A has a depth of 1, and B a depth of 0).
+ */
+enum dfs_state {
+       DFS_NONE = 0,
+       DFS_ACTIVE,
+       DFS_DONE,
+       DFS_NUM_STATES
+};
+
 /*
+ * The size of struct nearly determines pack-objects's memory
+ * consumption. This struct is packed tight for that reason. When you
+ * add or reorder something in this struct, think a bit about this.
+ *
  * basic object info
  * -----------------
  * idx.oid is filled up before delta searching starts. idx.crc32 is
@@ -12,7 +44,9 @@
  *
  * "size" is the uncompressed object size. Compressed size of the raw
  * data for an object in a pack is not stored anywhere but is computed
- * and made available when reverse .idx is made.
+ * and made available when reverse .idx is made. Note that when a
+ * delta is reused, "size" is the uncompressed _delta_ size, not the
+ * canonical one after the delta has been applied.
  *
  * "hash" contains a path name hash which is used for sorting the
  * delta list and also during delta searching. Once prepare_pack()
  */
 struct object_entry {
        struct pack_idx_entry idx;
-       unsigned long size;     /* uncompressed size */
-       struct packed_git *in_pack;     /* already in pack */
-       off_t in_pack_offset;
-       struct object_entry *delta;     /* delta base object */
-       struct object_entry *delta_child; /* deltified objects who bases me */
-       struct object_entry *delta_sibling; /* other deltified objects who
-                                            * uses the same base as me
-                                            */
        void *delta_data;       /* cached delta (uncompressed) */
-       unsigned long delta_size;       /* delta data size (uncompressed) */
-       unsigned long z_delta_size;     /* delta data size (compressed) */
+       off_t in_pack_offset;
+       uint32_t hash;                  /* name hint hash */
+       unsigned size_:OE_SIZE_BITS;
+       unsigned size_valid:1;
+       uint32_t delta_idx;     /* delta base object */
+       uint32_t delta_child_idx; /* deltified objects who bases me */
+       uint32_t delta_sibling_idx; /* other deltified objects who
+                                    * uses the same base as me
+                                    */
+       unsigned delta_size_:OE_DELTA_SIZE_BITS; /* delta data size (uncompressed) */
+       unsigned delta_size_valid:1;
+       unsigned in_pack_idx:OE_IN_PACK_BITS;   /* already in pack */
+       unsigned z_delta_size:OE_Z_DELTA_BITS;
+       unsigned type_valid:1;
        unsigned type_:TYPE_BITS;
+       unsigned no_try_delta:1;
        unsigned in_pack_type:TYPE_BITS; /* could be delta */
-       unsigned type_valid:1;
-       uint32_t hash;                  /* name hint hash */
-       unsigned int in_pack_pos;
-       unsigned char in_pack_header_size;
        unsigned preferred_base:1; /*
                                    * we do not pack this, but is available
                                    * to be used as the base object to delta
                                    * objects against.
                                    */
-       unsigned no_try_delta:1;
        unsigned tagged:1; /* near the very tip of refs */
        unsigned filled:1; /* assigned write-order */
+       unsigned dfs_state:OE_DFS_STATE_BITS;
+       unsigned char in_pack_header_size;
+       unsigned depth:OE_DEPTH_BITS;
 
        /*
-        * State flags for depth-first search used for analyzing delta cycles.
+        * pahole results on 64-bit linux (gcc and clang)
+        *
+        *   size: 80, bit_padding: 20 bits, holes: 8 bits
+        *
+        * and on 32-bit (gcc)
         *
-        * The depth is measured in delta-links to the base (so if A is a delta
-        * against B, then A has a depth of 1, and B a depth of 0).
+        *   size: 76, bit_padding: 20 bits, holes: 8 bits
         */
-       enum {
-               DFS_NONE = 0,
-               DFS_ACTIVE,
-               DFS_DONE
-       } dfs_state;
-       int depth;
 };
 
 struct packing_data {
@@ -94,8 +128,22 @@ struct packing_data {
 
        int32_t *index;
        uint32_t index_size;
+
+       unsigned int *in_pack_pos;
+
+       /*
+        * Only one of these can be non-NULL and they have different
+        * sizes. if in_pack_by_idx is allocated, oe_in_pack() returns
+        * the pack of an object using in_pack_idx field. If not,
+        * in_pack[] array is used the same way as in_pack_pos[]
+        */
+       struct packed_git **in_pack_by_idx;
+       struct packed_git **in_pack;
+
+       uintmax_t oe_size_limit;
 };
 
+void prepare_packing_data(struct packing_data *pdata);
 struct object_entry *packlist_alloc(struct packing_data *pdata,
                                    const unsigned char *sha1,
                                    uint32_t index_pos);
@@ -139,4 +187,163 @@ static inline void oe_set_type(struct object_entry *e,
        e->type_ = (unsigned)type;
 }
 
+static inline unsigned int oe_in_pack_pos(const struct packing_data *pack,
+                                         const struct object_entry *e)
+{
+       return pack->in_pack_pos[e - pack->objects];
+}
+
+static inline void oe_set_in_pack_pos(const struct packing_data *pack,
+                                     const struct object_entry *e,
+                                     unsigned int pos)
+{
+       pack->in_pack_pos[e - pack->objects] = pos;
+}
+
+static inline struct packed_git *oe_in_pack(const struct packing_data *pack,
+                                           const struct object_entry *e)
+{
+       if (pack->in_pack_by_idx)
+               return pack->in_pack_by_idx[e->in_pack_idx];
+       else
+               return pack->in_pack[e - pack->objects];
+}
+
+void oe_map_new_pack(struct packing_data *pack,
+                    struct packed_git *p);
+static inline void oe_set_in_pack(struct packing_data *pack,
+                                 struct object_entry *e,
+                                 struct packed_git *p)
+{
+       if (!p->index)
+               oe_map_new_pack(pack, p);
+       if (pack->in_pack_by_idx)
+               e->in_pack_idx = p->index;
+       else
+               pack->in_pack[e - pack->objects] = p;
+}
+
+static inline struct object_entry *oe_delta(
+               const struct packing_data *pack,
+               const struct object_entry *e)
+{
+       if (e->delta_idx)
+               return &pack->objects[e->delta_idx - 1];
+       return NULL;
+}
+
+static inline void oe_set_delta(struct packing_data *pack,
+                               struct object_entry *e,
+                               struct object_entry *delta)
+{
+       if (delta)
+               e->delta_idx = (delta - pack->objects) + 1;
+       else
+               e->delta_idx = 0;
+}
+
+static inline struct object_entry *oe_delta_child(
+               const struct packing_data *pack,
+               const struct object_entry *e)
+{
+       if (e->delta_child_idx)
+               return &pack->objects[e->delta_child_idx - 1];
+       return NULL;
+}
+
+static inline void oe_set_delta_child(struct packing_data *pack,
+                                     struct object_entry *e,
+                                     struct object_entry *delta)
+{
+       if (delta)
+               e->delta_child_idx = (delta - pack->objects) + 1;
+       else
+               e->delta_child_idx = 0;
+}
+
+static inline struct object_entry *oe_delta_sibling(
+               const struct packing_data *pack,
+               const struct object_entry *e)
+{
+       if (e->delta_sibling_idx)
+               return &pack->objects[e->delta_sibling_idx - 1];
+       return NULL;
+}
+
+static inline void oe_set_delta_sibling(struct packing_data *pack,
+                                       struct object_entry *e,
+                                       struct object_entry *delta)
+{
+       if (delta)
+               e->delta_sibling_idx = (delta - pack->objects) + 1;
+       else
+               e->delta_sibling_idx = 0;
+}
+
+unsigned long oe_get_size_slow(struct packing_data *pack,
+                              const struct object_entry *e);
+static inline unsigned long oe_size(struct packing_data *pack,
+                                   const struct object_entry *e)
+{
+       if (e->size_valid)
+               return e->size_;
+
+       return oe_get_size_slow(pack, e);
+}
+
+static inline int oe_size_less_than(struct packing_data *pack,
+                                   const struct object_entry *lhs,
+                                   unsigned long rhs)
+{
+       if (lhs->size_valid)
+               return lhs->size_ < rhs;
+       if (rhs < pack->oe_size_limit) /* rhs < 2^x <= lhs ? */
+               return 0;
+       return oe_get_size_slow(pack, lhs) < rhs;
+}
+
+static inline int oe_size_greater_than(struct packing_data *pack,
+                                      const struct object_entry *lhs,
+                                      unsigned long rhs)
+{
+       if (lhs->size_valid)
+               return lhs->size_ > rhs;
+       if (rhs < pack->oe_size_limit) /* rhs < 2^x <= lhs ? */
+               return 1;
+       return oe_get_size_slow(pack, lhs) > rhs;
+}
+
+static inline void oe_set_size(struct packing_data *pack,
+                              struct object_entry *e,
+                              unsigned long size)
+{
+       if (size < pack->oe_size_limit) {
+               e->size_ = size;
+               e->size_valid = 1;
+       } else {
+               e->size_valid = 0;
+               if (oe_get_size_slow(pack, e) != size)
+                       BUG("'size' is supposed to be the object size!");
+       }
+}
+
+static inline unsigned long oe_delta_size(struct packing_data *pack,
+                                         const struct object_entry *e)
+{
+       if (e->delta_size_valid)
+               return e->delta_size_;
+       return oe_size(pack, e);
+}
+
+static inline void oe_set_delta_size(struct packing_data *pack,
+                                    struct object_entry *e,
+                                    unsigned long size)
+{
+       e->delta_size_ = size;
+       e->delta_size_valid = e->delta_size_ == size;
+       if (!e->delta_size_valid && size != oe_size(pack, e))
+               BUG("this can only happen in check_object() "
+                   "where delta size is the same as entry size");
+}
+
 #endif