Merge branch 'ps/odb-source-packed' into jch

The packed object source has been refactored into a proper struct
odb_source.

* ps/odb-source-packed:
  odb/source-packed: drop pointer to "files" parent source
  midx: refactor interfaces to work on "packed" source
  odb/source-packed: stub out remaining functions
  odb/source-packed: wire up `freshen_object()` callback
  odb/source-packed: wire up `find_abbrev_len()` callback
  odb/source-packed: wire up `count_objects()` callback
  odb/source-packed: wire up `for_each_object()` callback
  odb/source-packed: wire up `read_object_stream()` callback
  odb/source-packed: wire up `read_object_info()` callback
  packfile: use higher-level interface to implement `has_object_pack()`
  odb/source-packed: wire up `reprepare()` callback
  odb/source-packed: wire up `close()` callback
  odb/source-packed: start converting to a proper `struct odb_source`
  odb/source-packed: store pointer to "files" instead of generic source
  packfile: move packed source into "odb/" subsystem
  packfile: split out packfile list logic
  packfile: rename `struct packfile_store` to `odb_source_packed`

diff --cc Makefile
Simple merge

diff --cc builtin/cat-file.c
Simple merge

diff --cc builtin/grep.c
Simple merge

diff --cc builtin/pack-objects.c
Simple merge

diff --cc builtin/repack.c
Simple merge

diff --cc commit-graph.c
Simple merge

diff --cc midx-write.c
Simple merge

diff --cc odb/source-packed.h
index 0000000000000000000000000000000000000000,88994098c18e7d12ac6d57566d63ecdf5cdc35a6..f0724b204c922334d16b84447d2cef967ea76869
mode 000000,100644..100644
--- /dev/null
--- 2/odb/source-packed.h
+++ b/odb/source-packed.h
@@@ -1,0 -1,94 +1,94 @@@
 -       * This is usually desireable, but there are exceptions. One exception
+ #ifndef ODB_SOURCE_PACKED_H
+ #define ODB_SOURCE_PACKED_H
+ 
+ #include "odb/source.h"
+ #include "packfile-list.h"
+ #include "strmap.h"
+ 
+ /*
+  * A store that manages packfiles for a given object database.
+  */
+ struct odb_source_packed {
+       struct odb_source base;
+ 
+       /*
+        * The list of packfiles in the order in which they have been most
+        * recently used.
+        */
+       struct packfile_list packs;
+ 
+       /*
+        * Cache of packfiles which are marked as "kept", either because there
+        * is an on-disk ".keep" file or because they are marked as "kept" in
+        * memory.
+        *
+        * Should not be accessed directly, but via
+        * `packfile_store_get_kept_pack_cache()`. The list of packs gets
+        * invalidated when the stored flags and the flags passed to
+        * `packfile_store_get_kept_pack_cache()` mismatch.
+        */
+       struct {
+               struct packed_git **packs;
+               unsigned flags;
+       } kept_cache;
+ 
+       /* The multi-pack index that belongs to this specific packfile store. */
+       struct multi_pack_index *midx;
+ 
+       /*
+        * A map of packfile names to packed_git structs for tracking which
+        * packs have been loaded already.
+        */
+       struct strmap packs_by_path;
+ 
+       /*
+        * Whether packfiles have already been populated with this store's
+        * packs.
+        */
+       bool initialized;
+ 
+       /*
+        * Usually, packfiles will be reordered to the front of the `packs`
+        * list whenever an object is looked up via them. This has the effect
+        * that packs that contain a lot of accessed objects will be located
+        * towards the front.
+        *
++       * This is usually desirable, but there are exceptions. One exception
+        * is when the looking up multiple objects in a loop for each packfile.
+        * In that case, we may easily end up with an infinite loop as the
+        * packfiles get reordered to the front repeatedly.
+        *
+        * Setting this field to `true` thus disables these reorderings.
+        */
+       bool skip_mru_updates;
+ };
+ 
+ /*
+  * Allocate and initialize a new empty packfile store for the given object
+  * database.
+  */
+ struct odb_source_packed *odb_source_packed_new(struct object_database *odb,
+                                               const char *path,
+                                               bool local);
+ 
+ /*
+  * Cast the given object database source to the packed backend. This will cause
+  * a BUG in case the source doesn't use this backend.
+  */
+ static inline struct odb_source_packed *odb_source_packed_downcast(struct odb_source *source)
+ {
+       if (source->type != ODB_SOURCE_PACKED)
+               BUG("trying to downcast source of type '%d' to packed", source->type);
+       return container_of(source, struct odb_source_packed, base);
+ }
+ 
+ /*
+  * Prepare the source by loading packfiles and multi-pack indices for
+  * all alternates. This becomes a no-op if the source is already prepared.
+  *
+  * It shouldn't typically be necessary to call this function directly, as
+  * functions that access the source know to prepare it.
+  */
+ void odb_source_packed_prepare(struct odb_source_packed *source);
+ 
+ #endif

diff --cc odb/source.h
Simple merge

diff --cc pack-bitmap.c
Simple merge

diff --cc packfile.c
Simple merge

diff --cc packfile.h
index defb6f442cca09924bc135b770d95dc33bc078b2,71a71017ee1058443902369a181e1e7732ae0454..2329a697014a6685f4e9f7de29267c19b050ef9f
--- 1/packfile.h
--- 2/packfile.h
+++ b/packfile.h
@@@ -454,11 -292,14 +292,15 @@@ off_t nth_packed_object_offset(const st
   */
  off_t find_pack_entry_one(const struct object_id *oid, struct packed_git *);
  
+ int packfile_fill_entry(struct packed_git *p,
+                       const struct object_id *oid,
+                       struct pack_entry *e);
+ 
  int is_pack_valid(struct packed_git *);
 -void *unpack_entry(struct repository *r, struct packed_git *, off_t, enum object_type *, unsigned long *);
 +void *unpack_entry(struct repository *r, struct packed_git *, off_t,
 +                 enum object_type *, size_t *);
  unsigned long unpack_object_header_buffer(const unsigned char *buf, unsigned long len, enum object_type *type, size_t *sizep);
 -unsigned long get_size_from_delta(struct packed_git *, struct pack_window **, off_t);
 +size_t get_size_from_delta(struct packed_git *, struct pack_window **, off_t);
  int unpack_object_header(struct packed_git *, struct pack_window **, off_t *, size_t *);
  off_t get_delta_base(struct packed_git *p, struct pack_window **w_curs,
                     off_t *curpos, enum object_type type,