diff options
Diffstat (limited to 'odb/source.h')
| -rw-r--r-- | odb/source.h | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/odb/source.h b/odb/source.h index 0e6c6abdb1..150becafe6 100644 --- a/odb/source.h +++ b/odb/source.h @@ -12,6 +12,45 @@ enum odb_source_type { ODB_SOURCE_FILES, }; +/* Flags that can be passed to `odb_read_object_info_extended()`. */ +enum object_info_flags { + /* Invoke lookup_replace_object() on the given hash. */ + OBJECT_INFO_LOOKUP_REPLACE = (1 << 0), + + /* Do not reprepare object sources when the first lookup has failed. */ + OBJECT_INFO_QUICK = (1 << 1), + + /* + * Do not attempt to fetch the object if missing (even if fetch_is_missing is + * nonzero). + */ + OBJECT_INFO_SKIP_FETCH_OBJECT = (1 << 2), + + /* Die if object corruption (not just an object being missing) was detected. */ + OBJECT_INFO_DIE_IF_CORRUPT = (1 << 3), + + /* + * We have already tried reading the object, but it couldn't be found + * via any of the attached sources, and are now doing a second read. + * This second read asks the individual sources to also evaluate + * whether any on-disk state may have changed that may have caused the + * object to appear. + * + * This flag is for internal use, only. The second read only occurs + * when `OBJECT_INFO_QUICK` was not passed. + */ + OBJECT_INFO_SECOND_READ = (1 << 4), + + /* + * This is meant for bulk prefetching of missing blobs in a partial + * clone. Implies OBJECT_INFO_SKIP_FETCH_OBJECT and OBJECT_INFO_QUICK. + */ + OBJECT_INFO_FOR_PREFETCH = (OBJECT_INFO_SKIP_FETCH_OBJECT | OBJECT_INFO_QUICK), +}; + +struct object_id; +struct object_info; + /* * 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 @@ -72,6 +111,33 @@ struct odb_source { * example just been repacked so that new objects will become visible. */ void (*reprepare)(struct odb_source *source); + + /* + * This callback is expected to read object information from the object + * database source. The object info will be partially populated with + * pointers for each bit of information that was requested by the + * caller. + * + * The flags field is a combination of `OBJECT_INFO` flags. Only the + * following fields need to be handled by the backend: + * + * - `OBJECT_INFO_QUICK` indicates it is fine to use caches without + * re-verifying the data. + * + * - `OBJECT_INFO_SECOND_READ` indicates that the initial object + * lookup has failed and that the object sources should check + * whether any of its on-disk state has changed that may have + * caused the object to appear. Sources are free to ignore the + * second read in case they know that the first read would have + * already surfaced the object without reloading any on-disk state. + * + * The callback is expected to return a negative error code in case + * reading the object has failed, 0 otherwise. + */ + int (*read_object_info)(struct odb_source *source, + const struct object_id *oid, + struct object_info *oi, + enum object_info_flags flags); }; /* @@ -131,4 +197,16 @@ static inline void odb_source_reprepare(struct odb_source *source) source->reprepare(source); } +/* + * Read an object from the object database source identified by its object ID. + * Returns 0 on success, a negative error code otherwise. + */ +static inline int odb_source_read_object_info(struct odb_source *source, + const struct object_id *oid, + struct object_info *oi, + enum object_info_flags flags) +{ + return source->read_object_info(source, oid, oi, flags); +} + #endif |