The directory listing API is used to enumerate paths in the work tree,
optionally taking .git/info/exclude and .gitignore files per
directory into account.
Data structure
struct dir_struct structure is used to pass directory traversal
options to the library and to record the paths discovered.  A single
struct dir_struct is used regardless of whether or not the traversal
recursively descends into subdirectories.
The notable options are:
- 
exclude_per_dir
- 
The name of the file to be read in each directory for excluded files (typically .gitignore).
- 
flags
- 
A bit-field of options (the *IGNORED*flags are mutually exclusive):- 
DIR_SHOW_IGNORED
- 
Return just ignored files in entries[], not untracked files.
- 
DIR_SHOW_IGNORED_TOO
- 
Similar to DIR_SHOW_IGNORED, but return ignored files inignored[]in addition to untracked files inentries[].
- 
DIR_COLLECT_IGNORED
- 
Special mode for git-add. Return ignored files in ignored[]and untracked files inentries[]. Only returns ignored files that match pathspec exactly (no wildcards). Does not recurse into ignored directories.
- 
DIR_SHOW_OTHER_DIRECTORIES
- 
Include a directory that is not tracked. 
- 
DIR_HIDE_EMPTY_DIRECTORIES
- 
Do not include a directory that is not tracked and is empty. 
- 
DIR_NO_GITLINKS
- 
If set, recurse into a directory that looks like a Git directory. Otherwise it is shown as a directory. 
 
- 
The result of the enumeration is left in these fields:
- 
entries[]
- 
An array of struct dir_entry, each element of which describes a path.
- 
nr
- 
The number of members in entries[]array.
- 
alloc
- 
Internal use; keeps track of allocation of entries[]array.
- 
ignored[]
- 
An array of struct dir_entry, used for ignored paths with theDIR_SHOW_IGNORED_TOOandDIR_COLLECT_IGNOREDflags.
- 
ignored_nr
- 
The number of members in ignored[]array.
Calling sequence
Note: index may be looked at for .gitignore files that are CE_SKIP_WORKTREE marked. If you to exclude files, make sure you have loaded index first.
- 
Prepare struct dir_struct dirand clear it withmemset(&dir, 0, sizeof(dir)).
- 
To add single exclude pattern, call add_exclude_list()and thenadd_exclude().
- 
To add patterns from a file (e.g. .git/info/exclude), calladd_excludes_from_file(), and/or setdir.exclude_per_dir. A short-hand functionsetup_standard_excludes()can be used to set up the standard set of exclude settings.
- 
Set options described in the Data Structure section above. 
- 
Call read_directory().
- 
Use dir.entries[].
- 
Call clear_directory()when none of the contained elements are no longer in use.
(JC)