object-store-ll.h: split this header out of object-store.h

The vast majority of files including object-store.h did not need dir.h
nor khash.h.  Split the header into two files, and let most just depend
upon object-store-ll.h, while letting the two callers that need it
depend on the full object-store.h.

After this patch:
    $ git grep -h include..object-store | sort | uniq -c
          2 #include "object-store.h"
        129 #include "object-store-ll.h"

Diff best viewed with `--color-moved`.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 533 insertions, 0 deletions

diff --git a/object-store-ll.h b/object-store-ll.h
new file mode 100644
index 0000000000..e8f22cdb1b
--- /dev/null
+++ b/object-store-ll.h
@@ -0,0 +1,533 @@
+#ifndef OBJECT_STORE_LL_H
+#define OBJECT_STORE_LL_H
+
+#include "hashmap.h"
+#include "object.h"
+#include "list.h"
+#include "thread-utils.h"
+#include "oidset.h"
+
+struct oidmap;
+struct oidtree;
+struct strbuf;
+
+struct object_directory {
+	struct object_directory *next;
+
+	/*
+	 * Used to store the results of readdir(3) calls when we are OK
+	 * sacrificing accuracy due to races for speed. That includes
+	 * object existence with OBJECT_INFO_QUICK, as well as
+	 * our search for unique abbreviated hashes. Don't use it for tasks
+	 * requiring greater accuracy!
+	 *
+	 * Be sure to call odb_load_loose_cache() before using.
+	 */
+	uint32_t loose_objects_subdir_seen[8]; /* 256 bits */
+	struct oidtree *loose_objects_cache;
+
+	/*
+	 * This is a temporary object store created by the tmp_objdir
+	 * facility. Disable ref updates since the objects in the store
+	 * might be discarded on rollback.
+	 */
+	int disable_ref_updates;
+
+	/*
+	 * This object store is ephemeral, so there is no need to fsync.
+	 */
+	int will_destroy;
+
+	/*
+	 * Path to the alternative object store. If this is a relative path,
+	 * it is relative to the current working directory.
+	 */
+	char *path;
+};
+
+struct input_stream {
+	const void *(*read)(struct input_stream *, unsigned long *len);
+	void *data;
+	int is_finished;
+};
+
+void prepare_alt_odb(struct repository *r);
+int has_alt_odb(struct repository *r);
+char *compute_alternate_path(const char *path, struct strbuf *err);
+struct object_directory *find_odb(struct repository *r, const char *obj_dir);
+typedef int alt_odb_fn(struct object_directory *, void *);
+int foreach_alt_odb(alt_odb_fn, void*);
+typedef void alternate_ref_fn(const struct object_id *oid, void *);
+void for_each_alternate_ref(alternate_ref_fn, void *);
+
+/*
+ * Add the directory to the on-disk alternates file; the new entry will also
+ * take effect in the current process.
+ */
+void add_to_alternates_file(const char *dir);
+
+/*
+ * Add the directory to the in-memory list of alternates (along with any
+ * recursive alternates it points to), but do not modify the on-disk alternates
+ * file.
+ */
+void add_to_alternates_memory(const char *dir);
+
+/*
+ * Replace the current writable object directory with the specified temporary
+ * object directory; returns the former primary object directory.
+ */
+struct object_directory *set_temporary_primary_odb(const char *dir, int will_destroy);
+
+/*
+ * Restore a previous ODB replaced by set_temporary_main_odb.
+ */
+void restore_primary_odb(struct object_directory *restore_odb, const char *old_path);
+
+/*
+ * Populate and return the loose object cache array corresponding to the
+ * given object ID.
+ */
+struct oidtree *odb_loose_cache(struct object_directory *odb,
+				  const struct object_id *oid);
+
+/* Empty the loose object cache for the specified object directory. */
+void odb_clear_loose_cache(struct object_directory *odb);
+
+/* Clear and free the specified object directory */
+void free_object_directory(struct object_directory *odb);
+
+struct packed_git {
+	struct hashmap_entry packmap_ent;
+	struct packed_git *next;
+	struct list_head mru;
+	struct pack_window *windows;
+	off_t pack_size;
+	const void *index_data;
+	size_t index_size;
+	uint32_t num_objects;
+	uint32_t crc_offset;
+	struct oidset bad_objects;
+	int index_version;
+	time_t mtime;
+	int pack_fd;
+	int index;              /* for builtin/pack-objects.c */
+	unsigned pack_local:1,
+		 pack_keep:1,
+		 pack_keep_in_core:1,
+		 freshened:1,
+		 do_not_close:1,
+		 pack_promisor:1,
+		 multi_pack_index:1,
+		 is_cruft:1;
+	unsigned char hash[GIT_MAX_RAWSZ];
+	struct revindex_entry *revindex;
+	const uint32_t *revindex_data;
+	const uint32_t *revindex_map;
+	size_t revindex_size;
+	/*
+	 * mtimes_map points at the beginning of the memory mapped region of
+	 * this pack's corresponding .mtimes file, and mtimes_size is the size
+	 * of that .mtimes file
+	 */
+	const uint32_t *mtimes_map;
+	size_t mtimes_size;
+	/* something like ".git/objects/pack/xxxxx.pack" */
+	char pack_name[FLEX_ARRAY]; /* more */
+};
+
+struct multi_pack_index;
+
+static inline int pack_map_entry_cmp(const void *cmp_data UNUSED,
+				     const struct hashmap_entry *entry,
+				     const struct hashmap_entry *entry2,
+				     const void *keydata)
+{
+	const char *key = keydata;
+	const struct packed_git *pg1, *pg2;
+
+	pg1 = container_of(entry, const struct packed_git, packmap_ent);
+	pg2 = container_of(entry2, const struct packed_git, packmap_ent);
+
+	return strcmp(pg1->pack_name, key ? key : pg2->pack_name);
+}
+
+struct raw_object_store {
+	/*
+	 * Set of all object directories; the main directory is first (and
+	 * cannot be NULL after initialization). Subsequent directories are
+	 * alternates.
+	 */
+	struct object_directory *odb;
+	struct object_directory **odb_tail;
+	struct kh_odb_path_map *odb_by_path;
+
+	int loaded_alternates;
+
+	/*
+	 * A list of alternate object directories loaded from the environment;
+	 * this should not generally need to be accessed directly, but will
+	 * populate the "odb" list when prepare_alt_odb() is run.
+	 */
+	char *alternate_db;
+
+	/*
+	 * Objects that should be substituted by other objects
+	 * (see git-replace(1)).
+	 */
+	struct oidmap *replace_map;
+	unsigned replace_map_initialized : 1;
+	pthread_mutex_t replace_mutex; /* protect object replace functions */
+
+	struct commit_graph *commit_graph;
+	unsigned commit_graph_attempted : 1; /* if loading has been attempted */
+
+	/*
+	 * private data
+	 *
+	 * should only be accessed directly by packfile.c and midx.c
+	 */
+	struct multi_pack_index *multi_pack_index;
+
+	/*
+	 * private data
+	 *
+	 * should only be accessed directly by packfile.c
+	 */
+
+	struct packed_git *packed_git;
+	/* A most-recently-used ordered version of the packed_git list. */
+	struct list_head packed_git_mru;
+
+	struct {
+		struct packed_git **packs;
+		unsigned flags;
+	} kept_pack_cache;
+
+	/*
+	 * A map of packfiles to packed_git structs for tracking which
+	 * packs have been loaded already.
+	 */
+	struct hashmap pack_map;
+
+	/*
+	 * A fast, rough count of the number of objects in the repository.
+	 * These two fields are not meant for direct access. Use
+	 * repo_approximate_object_count() instead.
+	 */
+	unsigned long approximate_object_count;
+	unsigned approximate_object_count_valid : 1;
+
+	/*
+	 * Whether packed_git has already been populated with this repository's
+	 * packs.
+	 */
+	unsigned packed_git_initialized : 1;
+};
+
+struct raw_object_store *raw_object_store_new(void);
+void raw_object_store_clear(struct raw_object_store *o);
+
+/*
+ * Put in `buf` the name of the file in the local object database that
+ * would be used to store a loose object with the specified oid.
+ */
+const char *loose_object_path(struct repository *r, struct strbuf *buf,
+			      const struct object_id *oid);
+
+void *map_loose_object(struct repository *r, const struct object_id *oid,
+		       unsigned long *size);
+
+void *repo_read_object_file(struct repository *r,
+			    const struct object_id *oid,
+			    enum object_type *type,
+			    unsigned long *size);
+
+/* Read and unpack an object file into memory, write memory to an object file */
+int oid_object_info(struct repository *r, const struct object_id *, unsigned long *);
+
+void hash_object_file(const struct git_hash_algo *algo, const void *buf,
+		      unsigned long len, enum object_type type,
+		      struct object_id *oid);
+
+int write_object_file_flags(const void *buf, unsigned long len,
+			    enum object_type type, struct object_id *oid,
+			    unsigned flags);
+static inline int write_object_file(const void *buf, unsigned long len,
+				    enum object_type type, struct object_id *oid)
+{
+	return write_object_file_flags(buf, len, type, oid, 0);
+}
+
+int write_object_file_literally(const void *buf, unsigned long len,
+				const char *type, struct object_id *oid,
+				unsigned flags);
+int stream_loose_object(struct input_stream *in_stream, size_t len,
+			struct object_id *oid);
+
+/*
+ * Add an object file to the in-memory object store, without writing it
+ * to disk.
+ *
+ * Callers are responsible for calling write_object_file to record the
+ * object in persistent storage before writing any other new objects
+ * that reference it.
+ */
+int pretend_object_file(void *, unsigned long, enum object_type,
+			struct object_id *oid);
+
+int force_object_loose(const struct object_id *oid, time_t mtime);
+
+struct object_info {
+	/* Request */
+	enum object_type *typep;
+	unsigned long *sizep;
+	off_t *disk_sizep;
+	struct object_id *delta_base_oid;
+	struct strbuf *type_name;
+	void **contentp;
+
+	/* Response */
+	enum {
+		OI_CACHED,
+		OI_LOOSE,
+		OI_PACKED,
+		OI_DBCACHED
+	} whence;
+	union {
+		/*
+		 * struct {
+		 * 	... Nothing to expose in this case
+		 * } cached;
+		 * struct {
+		 * 	... Nothing to expose in this case
+		 * } loose;
+		 */
+		struct {
+			struct packed_git *pack;
+			off_t offset;
+			unsigned int is_delta;
+		} packed;
+	} u;
+};
+
+/*
+ * Initializer for a "struct object_info" that wants no items. You may
+ * also memset() the memory to all-zeroes.
+ */
+#define OBJECT_INFO_INIT { 0 }
+
+/* Invoke lookup_replace_object() on the given hash */
+#define OBJECT_INFO_LOOKUP_REPLACE 1
+/* Allow reading from a loose object file of unknown/bogus type */
+#define OBJECT_INFO_ALLOW_UNKNOWN_TYPE 2
+/* Do not retry packed storage after checking packed and loose storage */
+#define OBJECT_INFO_QUICK 8
+/*
+ * Do not attempt to fetch the object if missing (even if fetch_is_missing is
+ * nonzero).
+ */
+#define OBJECT_INFO_SKIP_FETCH_OBJECT 16
+/*
+ * This is meant for bulk prefetching of missing blobs in a partial
+ * clone. Implies OBJECT_INFO_SKIP_FETCH_OBJECT and OBJECT_INFO_QUICK
+ */
+#define OBJECT_INFO_FOR_PREFETCH (OBJECT_INFO_SKIP_FETCH_OBJECT | OBJECT_INFO_QUICK)
+
+/* Die if object corruption (not just an object being missing) was detected. */
+#define OBJECT_INFO_DIE_IF_CORRUPT 32
+
+int oid_object_info_extended(struct repository *r,
+			     const struct object_id *,
+			     struct object_info *, unsigned flags);
+
+/*
+ * Open the loose object at path, check its hash, and return the contents,
+ * use the "oi" argument to assert things about the object, or e.g. populate its
+ * type, and size. If the object is a blob, then "contents" may return NULL,
+ * to allow streaming of large blobs.
+ *
+ * Returns 0 on success, negative on error (details may be written to stderr).
+ */
+int read_loose_object(const char *path,
+		      const struct object_id *expected_oid,
+		      struct object_id *real_oid,
+		      void **contents,
+		      struct object_info *oi);
+
+/* Retry packed storage after checking packed and loose storage */
+#define HAS_OBJECT_RECHECK_PACKED 1
+
+/*
+ * Returns 1 if the object exists. This function will not lazily fetch objects
+ * in a partial clone.
+ */
+int has_object(struct repository *r, const struct object_id *oid,
+	       unsigned flags);
+
+/*
+ * These macros and functions are deprecated. If checking existence for an
+ * object that is likely to be missing and/or whose absence is relatively
+ * inconsequential (or is consequential but the caller is prepared to handle
+ * it), use has_object(), which has better defaults (no lazy fetch in a partial
+ * clone and no rechecking of packed storage). In the unlikely event that a
+ * caller needs to assert existence of an object that it fully expects to
+ * exist, and wants to trigger a lazy fetch in a partial clone, use
+ * oid_object_info_extended() with a NULL struct object_info.
+ *
+ * These functions can be removed once all callers have migrated to
+ * has_object() and/or oid_object_info_extended().
+ */
+int repo_has_object_file(struct repository *r, const struct object_id *oid);
+int repo_has_object_file_with_flags(struct repository *r,
+				    const struct object_id *oid, int flags);
+
+/*
+ * Return true iff an alternate object database has a loose object
+ * with the specified name.  This function does not respect replace
+ * references.
+ */
+int has_loose_object_nonlocal(const struct object_id *);
+
+int has_loose_object(const struct object_id *);
+
+/**
+ * format_object_header() is a thin wrapper around s xsnprintf() that
+ * writes the initial "<type> <obj-len>" part of the loose object
+ * header. It returns the size that snprintf() returns + 1.
+ */
+int format_object_header(char *str, size_t size, enum object_type type,
+			 size_t objsize);
+
+void assert_oid_type(const struct object_id *oid, enum object_type expect);
+
+/*
+ * Enabling the object read lock allows multiple threads to safely call the
+ * following functions in parallel: repo_read_object_file(),
+ * read_object_with_reference(), oid_object_info() and oid_object_info_extended().
+ *
+ * obj_read_lock() and obj_read_unlock() may also be used to protect other
+ * section which cannot execute in parallel with object reading. Since the used
+ * lock is a recursive mutex, these sections can even contain calls to object
+ * reading functions. However, beware that in these cases zlib inflation won't
+ * be performed in parallel, losing performance.
+ *
+ * TODO: oid_object_info_extended()'s call stack has a recursive behavior. If
+ * any of its callees end up calling it, this recursive call won't benefit from
+ * parallel inflation.
+ */
+void enable_obj_read_lock(void);
+void disable_obj_read_lock(void);
+
+extern int obj_read_use_lock;
+extern pthread_mutex_t obj_read_mutex;
+
+static inline void obj_read_lock(void)
+{
+	if(obj_read_use_lock)
+		pthread_mutex_lock(&obj_read_mutex);
+}
+
+static inline void obj_read_unlock(void)
+{
+	if(obj_read_use_lock)
+		pthread_mutex_unlock(&obj_read_mutex);
+}
+
+/*
+ * Iterate over the files in the loose-object parts of the object
+ * directory "path", triggering the following callbacks:
+ *
+ *  - loose_object is called for each loose object we find.
+ *
+ *  - loose_cruft is called for any files that do not appear to be
+ *    loose objects. Note that we only look in the loose object
+ *    directories "objects/[0-9a-f]{2}/", so we will not report
+ *    "objects/foobar" as cruft.
+ *
+ *  - loose_subdir is called for each top-level hashed subdirectory
+ *    of the object directory (e.g., "$OBJDIR/f0"). It is called
+ *    after the objects in the directory are processed.
+ *
+ * Any callback that is NULL will be ignored. Callbacks returning non-zero
+ * will end the iteration.
+ *
+ * In the "buf" variant, "path" is a strbuf which will also be used as a
+ * scratch buffer, but restored to its original contents before
+ * the function returns.
+ */
+typedef int each_loose_object_fn(const struct object_id *oid,
+				 const char *path,
+				 void *data);
+typedef int each_loose_cruft_fn(const char *basename,
+				const char *path,
+				void *data);
+typedef int each_loose_subdir_fn(unsigned int nr,
+				 const char *path,
+				 void *data);
+int for_each_file_in_obj_subdir(unsigned int subdir_nr,
+				struct strbuf *path,
+				each_loose_object_fn obj_cb,
+				each_loose_cruft_fn cruft_cb,
+				each_loose_subdir_fn subdir_cb,
+				void *data);
+int for_each_loose_file_in_objdir(const char *path,
+				  each_loose_object_fn obj_cb,
+				  each_loose_cruft_fn cruft_cb,
+				  each_loose_subdir_fn subdir_cb,
+				  void *data);
+int for_each_loose_file_in_objdir_buf(struct strbuf *path,
+				      each_loose_object_fn obj_cb,
+				      each_loose_cruft_fn cruft_cb,
+				      each_loose_subdir_fn subdir_cb,
+				      void *data);
+
+/* Flags for for_each_*_object() below. */
+enum for_each_object_flags {
+	/* Iterate only over local objects, not alternates. */
+	FOR_EACH_OBJECT_LOCAL_ONLY = (1<<0),
+
+	/* Only iterate over packs obtained from the promisor remote. */
+	FOR_EACH_OBJECT_PROMISOR_ONLY = (1<<1),
+
+	/*
+	 * Visit objects within a pack in packfile order rather than .idx order
+	 */
+	FOR_EACH_OBJECT_PACK_ORDER = (1<<2),
+
+	/* Only iterate over packs that are not marked as kept in-core. */
+	FOR_EACH_OBJECT_SKIP_IN_CORE_KEPT_PACKS = (1<<3),
+
+	/* Only iterate over packs that do not have .keep files. */
+	FOR_EACH_OBJECT_SKIP_ON_DISK_KEPT_PACKS = (1<<4),
+};
+
+/*
+ * Iterate over all accessible loose objects without respect to
+ * reachability. By default, this includes both local and alternate objects.
+ * The order in which objects are visited is unspecified.
+ *
+ * Any flags specific to packs are ignored.
+ */
+int for_each_loose_object(each_loose_object_fn, void *,
+			  enum for_each_object_flags flags);
+
+/*
+ * Iterate over all accessible packed objects without respect to reachability.
+ * By default, this includes both local and alternate packs.
+ *
+ * Note that some objects may appear twice if they are found in multiple packs.
+ * Each pack is visited in an unspecified order. By default, objects within a
+ * pack are visited in pack-idx order (i.e., sorted by oid).
+ */
+typedef int each_packed_object_fn(const struct object_id *oid,
+				  struct packed_git *pack,
+				  uint32_t pos,
+				  void *data);
+int for_each_object_in_pack(struct packed_git *p,
+			    each_packed_object_fn, void *data,
+			    enum for_each_object_flags flags);
+int for_each_packed_object(each_packed_object_fn, void *,
+			   enum for_each_object_flags flags);
+
+#endif /* OBJECT_STORE_LL_H */