git/object.h, branch v2.1.2

add object_as_type helper for casting objects

2014-07-14T01:59:05Z

When we call lookup_commit, lookup_tree, etc, the logic goes something like: 1. Look for an existing object struct. If we don't have one, allocate and return a new one. 2. Double check that any object we have is the expected type (and complain and return NULL otherwise). 3. Convert an object with type OBJ_NONE (from a prior call to lookup_unknown_object) to the expected type. We can encapsulate steps 2 and 3 in a helper function which checks whether we have the expected object type, converts OBJ_NONE as appropriate, and returns the object. Not only does this shorten the code, but it also provides one central location for converting OBJ_NONE objects into objects of other types. Future patches will use that to enforce type-specific invariants. Since this is a refactoring, we would want it to behave exactly as the current code. It takes a little reasoning to see that this is the case: - for lookup_{commit,tree,etc} functions, we are just pulling steps 2 and 3 into a function that does the same thing. - for the call in peel_object, we currently only do step 3 (but we want to consolidate it with the others, as mentioned above). However, step 2 is a noop here, as the surrounding conditional makes sure we have OBJ_NONE (which we want to keep to avoid an extraneous call to sha1_object_info). - for the call in lookup_commit_reference_gently, we are currently doing step 2 but not step 3. However, step 3 is a noop here. The object we got will have just come from deref_tag, which must have figured out the type for each object in order to know when to stop peeling. Therefore the type will never be OBJ_NONE. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

move setting of object->type to alloc_* functions

2014-07-14T01:59:05Z

The "struct object" type implements basic object polymorphism. Individual instances are allocated as concrete types (or as a union type that can store any object), and a "struct object *" can be cast into its real type after examining its "type" enum. This means it is dangerous to have a type field that does not match the allocation (e.g., setting the type field of a "struct blob" to "OBJ_COMMIT" would mean that a reader might read past the allocated memory). In most of the current code this is not a problem; the first thing we do after allocating an object is usually to set its type field by passing it to create_object. However, the virtual commits we create in merge-recursive.c do not ever get their type set. This does not seem to have caused problems in practice, though (presumably because we always pass around a "struct commit" pointer and never even look at the type). We can fix this oversight and also make it harder for future code to get it wrong by setting the type directly in the object allocation functions. This will also make it easier to fix problems with commit index allocation, as we know that any object allocated by alloc_commit_node will meet the invariant that an object with an OBJ_COMMIT type field will have a unique index number. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

Merge branch 'nd/log-show-linear-break'

2014-04-03T19:38:11Z

Attempts to show where a single-strand-of-pearls break in "git log" output. * nd/log-show-linear-break: log: add --show-linear-break to help see non-linear history object.h: centralize object flag allocation

log: add --show-linear-break to help see non-linear history

2014-03-25T22:09:49Z

Option explanation is in rev-list-options.txt. The interaction with -z is left undecided. Signed-off-by: Nguyễn Thái Ngọc Duy Signed-off-by: Junio C Hamano

object.h: centralize object flag allocation

2014-03-25T22:09:24Z

While the field "flags" is mainly used by the revision walker, it is also used in many other places. Centralize the whole flag allocation to one place for a better overview (and easier to move flags if we have too). Signed-off-by: Nguyễn Thái Ngọc Duy Signed-off-by: Junio C Hamano

Document some functions defined in object.c

2014-02-28T21:18:09Z

Signed-off-by: Michael Haggerty Acked-by: Nicolas Pitre Signed-off-by: Junio C Hamano

Merge branch 'mg/more-textconv'

2013-10-23T20:21:31Z

Make "git grep" and "git show" pay attention to --textconv when dealing with blob objects. * mg/more-textconv: grep: honor --textconv for the case rev:path grep: allow to use textconv filters t7008: demonstrate behavior of grep with textconv cat-file: do not die on --textconv without textconv filters show: honor --textconv for blobs diff_opt: track whether flags have been set explicitly t4030: demonstrate behavior of show with textconv

object_array_entry: fix memory handling of the name field

2013-06-02T22:28:46Z

Previously, the memory management of the object_array_entry::name field was inconsistent and undocumented. object_array_entries are ultimately created by a single function, add_object_array_with_mode(), which has an argument "const char *name". This function used to simply set the name field to reference the string pointed to by the name parameter, and nobody on the object_array side ever freed the memory. Thus, it assumed that the memory for the name field would be managed by the caller, and that the lifetime of that string would be at least as long as the lifetime of the object_array_entry. But callers were inconsistent: * Some passed pointers to constant strings or argv entries, which was OK. * Some passed pointers to newly-allocated memory, but didn't arrange for the memory ever to be freed. * Some passed the return value of sha1_to_hex(), which is a pointer to a statically-allocated buffer that can be overwritten at any time. * Some passed pointers to refnames that they received from a for_each_ref()-type iteration, but the lifetimes of such refnames is not guaranteed by the refs API. Bring consistency to this mess by changing object_array to make its own copy for the object_array_entry::name field and free this memory when an object_array_entry is deleted from the array. Many callers were passing the empty string as the name parameter, so as a performance optimization, treat the empty string specially. Instead of making a copy, store a pointer to a statically-allocated empty string to object_array_entry::name. When deleting such an entry, skip the free(). Change the callers that were already passing copies to add_object_array_with_mode() to either skip the copy, or (if the memory needed to be allocated anyway) freeing the memory itself. A part of this commit effectively reverts 70d26c6e76 read_revisions_from_stdin: make copies for handle_revision_arg because the copying introduced by that commit (which is still necessary) is now done at a deeper level. Signed-off-by: Michael Haggerty Signed-off-by: Junio C Hamano

object_array_remove_duplicates(): rewrite to reduce copying

2013-05-28T16:25:01Z

The old version copied one entry to its destination position, then deleted any matching entries from the tail of the array. This required the tail of the array to be copied multiple times. It didn't affect the complexity of the algorithm because the whole tail has to be searched through anyway. But all the copying was unnecessary. Instead, check for the existence of an entry with the same name in the *head* of the list before copying an entry to its final position. This way each entry has to be copied at most one time. Extract a helper function contains_name() to do a bit of the work. Signed-off-by: Michael Haggerty Signed-off-by: Junio C Hamano

object_array: add function object_array_filter()

2013-05-28T16:25:01Z

Add a function that allows unwanted entries in an object_array to be removed. This encapsulation is a step towards giving object_array ownership of its entries' name memory. Signed-off-by: Michael Haggerty Signed-off-by: Junio C Hamano