Merge branch 'tb/reverse-midx'

An on-disk reverse-index to map the in-pack location of an object
back to its object name across multiple packfiles is introduced.

* tb/reverse-midx:
  midx.c: improve cache locality in midx_pack_order_cmp()
  pack-revindex: write multi-pack reverse indexes
  pack-write.c: extract 'write_rev_file_order'
  pack-revindex: read multi-pack reverse indexes
  Documentation/technical: describe multi-pack reverse indexes
  midx: make some functions non-static
  midx: keep track of the checksum
  midx: don't free midx_name early
  midx: allow marking a pack as preferred
  t/helper/test-read-midx.c: add '--show-objects'
  builtin/multi-pack-index.c: display usage on unrecognized command
  builtin/multi-pack-index.c: don't enter bogus cmd_mode
  builtin/multi-pack-index.c: split sub-commands
  builtin/multi-pack-index.c: define common usage with a macro
  builtin/multi-pack-index.c: don't handle 'progress' separately
  builtin/multi-pack-index.c: inline 'flags' with options

1 files changed, 10 insertions, 1 deletions

diff --git a/midx.h b/midx.h
index b18cf53bc4..8684cf0fef 100644
--- a/midx.h
+++ b/midx.h
@@ -15,6 +15,10 @@ struct multi_pack_index {
 	const unsigned char *data;
 	size_t data_len;
 
+	const uint32_t *revindex_data;
+	const uint32_t *revindex_map;
+	size_t revindex_len;
+
 	uint32_t signature;
 	unsigned char version;
 	unsigned char hash_len;
@@ -36,10 +40,15 @@ struct multi_pack_index {
 };
 
 #define MIDX_PROGRESS     (1 << 0)
+#define MIDX_WRITE_REV_INDEX (1 << 1)
+
+char *get_midx_rev_filename(struct multi_pack_index *m);
 
 struct multi_pack_index *load_multi_pack_index(const char *object_dir, int local);
 int prepare_midx_pack(struct repository *r, struct multi_pack_index *m, uint32_t pack_int_id);
 int bsearch_midx(const struct object_id *oid, struct multi_pack_index *m, uint32_t *result);
+off_t nth_midxed_offset(struct multi_pack_index *m, uint32_t pos);
+uint32_t nth_midxed_pack_int_id(struct multi_pack_index *m, uint32_t pos);
 struct object_id *nth_midxed_object_oid(struct object_id *oid,
 					struct multi_pack_index *m,
 					uint32_t n);
@@ -47,7 +56,7 @@ int fill_midx_entry(struct repository *r, const struct object_id *oid, struct pa
 int midx_contains_pack(struct multi_pack_index *m, const char *idx_or_pack_name);
 int prepare_multi_pack_index_one(struct repository *r, const char *object_dir, int local);
 
-int write_midx_file(const char *object_dir, unsigned flags);
+int write_midx_file(const char *object_dir, const char *preferred_pack_name, unsigned flags);
 void clear_midx_file(struct repository *r);
 int verify_midx_file(struct repository *r, const char *object_dir, unsigned flags);
 int expire_midx_packs(struct repository *r, const char *object_dir, unsigned flags);