The tree walking API is used to traverse and inspect trees.
Data Structures
-
struct name_entry -
An entry in a tree. Each entry has a sha1 identifier, pathname, and mode.
-
struct tree_desc -
A semi-opaque data structure used to maintain the current state of the walk.
-
bufferis a pointer into the memory representation of the tree. It always points at the current entry being visited. -
sizecounts the number of bytes left in thebuffer. -
entrypoints to the current entry being visited.
-
-
struct traverse_info -
A structure used to maintain the state of a traversal.
-
prevpoints to the traverse_info which was used to descend into the current tree. If this is the top-level treeprevwill point to a dummy traverse_info. -
nameis the entry for the current tree (if the tree is a subtree). -
pathlenis the length of the full path for the current tree. -
conflictscan be used by callbacks to maintain directory-file conflicts. -
fnis a callback called for each entry in the tree. See Traversing for more information. -
datacan be anything thefncallback would want to use. -
show_all_errorstells whether to stop at the first error or not.
-
Initializing
-
init_tree_desc -
Initialize a
tree_descand decode its first entry. The buffer and size parameters are assumed to be the same as the buffer and size members ofstruct tree. -
fill_tree_descriptor -
Initialize a
tree_descand decode its first entry given the object ID of a tree. Returns thebuffermember if the latter is a valid tree identifier and NULL otherwise. -
setup_traverse_info -
Initialize a
traverse_infogiven the pathname of the tree to start traversing from. Thebaseargument is assumed to be thepathmember of thename_entrybeing recursed into unless the tree is a top-level tree in which case the empty string ("") is used.
Walking
-
tree_entry -
Visit the next entry in a tree. Returns 1 when there are more entries left to visit and 0 when all entries have been visited. This is commonly used in the test of a while loop.
-
tree_entry_len -
Calculate the length of a tree entry’s pathname. This utilizes the memory structure of a tree entry to avoid the overhead of using a generic strlen().
-
update_tree_entry -
Walk to the next entry in a tree. This is commonly used in conjunction with
tree_entry_extractto inspect the current entry. -
tree_entry_extract -
Decode the entry currently being visited (the one pointed to by
tree_desc'sentrymember) and return the sha1 of the entry. Thepathpandmodeparguments are set to the entry’s pathname and mode respectively. -
get_tree_entry -
Find an entry in a tree given a pathname and the sha1 of a tree to search. Returns 0 if the entry is found and -1 otherwise. The third and fourth parameters are set to the entry’s sha1 and mode respectively.
Traversing
-
traverse_trees -
Traverse
nnumber of trees in parallel. Thefncallback member oftraverse_infois called once for each tree entry. -
traverse_callback_t -
The arguments passed to the traverse callback are as follows:
-
ncounts the number of trees being traversed. -
maskhas its nth bit set if something exists in the nth entry. -
dirmaskhas its nth bit set if the nth tree’s entry is a directory. -
entryis an array of sizenwhere the nth entry is from the nth tree. -
infomaintains the state of the traversal.
Returning a negative value will terminate the traversal. Otherwise the return value is treated as an update mask. If the nth bit is set the nth tree will be updated and if the bit is not set the nth tree entry will be the same in the next callback invocation.
-
-
make_traverse_path -
Generate the full pathname of a tree entry based from the root of the traversal. For example, if the traversal has recursed into another tree named "bar" the pathname of an entry "baz" in the "bar" tree would be "bar/baz".
-
traverse_path_len -
Calculate the length of a pathname returned by
make_traverse_path. This utilizes the memory structure of a tree entry to avoid the overhead of using a generic strlen().
Authors
Written by Junio C Hamano <gitster@pobox.com> and Linus Torvalds <torvalds@linux-foundation.org>