#ifndef ODB_H #define ODB_H #include "hashmap.h" #include "object.h" #include "list.h" #include "oidset.h" #include "oidmap.h" #include "string-list.h" #include "thread-utils.h" struct oidmap; struct oidtree; struct strbuf; struct repository; struct multi_pack_index; /* * Compute the exact path an alternate is at and returns it. In case of * error NULL is returned and the human readable error is added to `err` * `path` may be relative and should point to $GIT_DIR. * `err` must not be null. */ char *compute_alternate_path(const char *path, struct strbuf *err); /* * The source is the part of the object database that stores the actual * objects. It thus encapsulates the logic to read and write the specific * on-disk format. An object database can have multiple sources: * * - The primary source, which is typically located in "$GIT_DIR/objects". * This is where new objects are usually written to. * * - Alternate sources, which are configured via "objects/info/alternates" or * via the GIT_ALTERNATE_OBJECT_DIRECTORIES environment variable. These * alternate sources are only used to read objects. */ struct odb_source { struct odb_source *next; /* Object database that owns this object source. */ struct object_database *odb; /* * 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; /* Map between object IDs for loose objects. */ struct loose_object_map *loose_map; /* * private data * * should only be accessed directly by packfile.c and midx.c */ struct multi_pack_index *midx; /* * 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 source. If this is a relative path, it is relative to * the current working directory. */ char *path; }; struct packed_git; struct cached_object_entry; /* * The object database encapsulates access to objects in a repository. It * manages one or more sources that store the actual objects which are * configured via alternates. */ struct object_database { /* Repository that owns this database. */ struct repository *repo; /* * Set of all object directories; the main directory is first (and * cannot be NULL after initialization). Subsequent directories are * alternates. */ struct odb_source *sources; struct odb_source **sources_tail; struct kh_odb_path_map *source_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 "sources" list when odb_prepare_alternates() 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 */ 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; /* * This is meant to hold a *small* number of objects that you would * want odb_read_object() to be able to return, but yet you do not want * to write them into the object store (e.g. a browse-only * application). */ struct cached_object_entry *cached_objects; size_t cached_object_nr, cached_object_alloc; /* * 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; /* * Submodule source paths that will be added as additional sources to * allow lookup of submodule objects via the main object database. */ struct string_list submodule_source_paths; }; struct object_database *odb_new(struct repository *repo); void odb_clear(struct object_database *o); /* * Find source by its object directory path. Dies in case the source couldn't * be found. */ struct odb_source *odb_find_source(struct object_database *odb, const char *obj_dir); /* * Replace the current writable object directory with the specified temporary * object directory; returns the former primary source. */ struct odb_source *odb_set_temporary_primary_source(struct object_database *odb, const char *dir, int will_destroy); /* * Restore the primary source that was previously replaced by * `odb_set_temporary_primary_source()`. */ void odb_restore_primary_source(struct object_database *odb, struct odb_source *restore_source, const char *old_path); /* * Call odb_add_submodule_source_by_path() to add the submodule at the given * path to a list. The object stores of all submodules in that list will be * added as additional sources in the object store when looking up objects. */ void odb_add_submodule_source_by_path(struct object_database *odb, const char *path); /* * Iterate through all alternates of the database and execute the provided * callback function for each of them. Stop iterating once the callback * function returns a non-zero value, in which case the value is bubbled up * from the callback. */ typedef int odb_for_each_alternate_fn(struct odb_source *, void *); int odb_for_each_alternate(struct object_database *odb, odb_for_each_alternate_fn cb, void *payload); /* * Iterate through all alternates of the database and yield their respective * references. */ typedef void odb_for_each_alternate_ref_fn(const struct object_id *oid, void *); void odb_for_each_alternate_ref(struct object_database *odb, odb_for_each_alternate_ref_fn cb, void *payload); /* * Create a temporary file rooted in the primary alternate's directory, or die * on failure. The filename is taken from "pattern", which should have the * usual "XXXXXX" trailer, and the resulting filename is written into the * "template" buffer. Returns the open descriptor. */ int odb_mkstemp(struct object_database *odb, struct strbuf *temp_filename, const char *pattern); /* * Prepare alternate object sources for the given database by reading * "objects/info/alternates" and opening the respective sources. */ void odb_prepare_alternates(struct object_database *odb); /* * Check whether the object database has any alternates. The primary object * source does not count as alternate. */ int odb_has_alternates(struct object_database *odb); /* * Add the directory to the on-disk alternates file; the new entry will also * take effect in the current process. */ void odb_add_to_alternates_file(struct object_database *odb, const char *dir); /* * Add the directory to the in-memory list of alternate sources (along with any * recursive alternates it points to), but do not modify the on-disk alternates * file. */ void odb_add_to_alternates_memory(struct object_database *odb, const char *dir); /* * Read an object from the database. Returns the object data and assigns object * type and size to the `type` and `size` pointers, if these pointers are * non-NULL. Returns a `NULL` pointer in case the object does not exist. * * This function dies on corrupt objects; the callers who want to deal with * them should arrange to call odb_read_object_info_extended() and give error * messages themselves. */ void *odb_read_object(struct object_database *odb, const struct object_id *oid, enum object_type *type, unsigned long *size); void *odb_read_object_peeled(struct object_database *odb, const struct object_id *oid, enum object_type required_type, unsigned long *size, struct object_id *oid_ret); /* * 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 odb_pretend_object(struct object_database *odb, void *buf, unsigned long len, enum object_type type, struct object_id *oid); struct object_info { /* Request */ enum object_type *typep; unsigned long *sizep; off_t *disk_sizep; struct object_id *delta_base_oid; 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 /* 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 /* * Read object info from the object database and populate the `object_info` * structure. Returns 0 on success, a negative error code otherwise. */ int odb_read_object_info_extended(struct object_database *odb, const struct object_id *oid, struct object_info *oi, unsigned flags); /* * Read a subset of object info for the given object ID. Returns an `enum * object_type` on success, a negative error code otherwise. If successful and * `sizep` is non-NULL, then the size of the object will be written to the * pointer. */ int odb_read_object_info(struct object_database *odb, const struct object_id *oid, unsigned long *sizep); enum { /* Retry packed storage after checking packed and loose storage */ HAS_OBJECT_RECHECK_PACKED = (1 << 0), /* Allow fetching the object in case the repository has a promisor remote. */ HAS_OBJECT_FETCH_PROMISOR = (1 << 1), }; /* * Returns 1 if the object exists. This function will not lazily fetch objects * in a partial clone by default. */ int odb_has_object(struct object_database *odb, const struct object_id *oid, unsigned flags); void odb_assert_oid_type(struct object_database *odb, 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: odb_read_object(), * odb_read_object_peeled(), odb_read_object_info() and odb(). * * 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: odb_read_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); } /* Flags for for_each_*_object(). */ 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), }; enum { /* * By default, `odb_write_object()` does not actually write anything * into the object store, but only computes the object ID. This flag * changes that so that the object will be written as a loose object * and persisted. */ WRITE_OBJECT_PERSIST = (1 << 0), /* * Do not print an error in case something goes wrong. */ WRITE_OBJECT_SILENT = (1 << 1), }; /* * Write an object into the object database. The object is being written into * the local alternate of the repository. If provided, the converted object ID * as well as the compatibility object ID are written to the respective * pointers. * * Returns 0 on success, a negative error code otherwise. */ int odb_write_object_ext(struct object_database *odb, const void *buf, unsigned long len, enum object_type type, struct object_id *oid, struct object_id *compat_oid, unsigned flags); static inline int odb_write_object(struct object_database *odb, const void *buf, unsigned long len, enum object_type type, struct object_id *oid) { return odb_write_object_ext(odb, buf, len, type, oid, NULL, 0); } /* Compatibility wrappers, to be removed once Git 2.51 has been released. */ #include "repository.h" static inline int oid_object_info_extended(struct repository *r, const struct object_id *oid, struct object_info *oi, unsigned flags) { return odb_read_object_info_extended(r->objects, oid, oi, flags); } static inline int oid_object_info(struct repository *r, const struct object_id *oid, unsigned long *sizep) { return odb_read_object_info(r->objects, oid, sizep); } static inline void *repo_read_object_file(struct repository *r, const struct object_id *oid, enum object_type *type, unsigned long *size) { return odb_read_object(r->objects, oid, type, size); } static inline int has_object(struct repository *r, const struct object_id *oid, unsigned flags) { return odb_has_object(r->objects, oid, flags); } #endif /* ODB_H */