diff options
Diffstat (limited to 'cache.h')
| -rw-r--r-- | cache.h | 48 |
1 files changed, 46 insertions, 2 deletions
@@ -1072,8 +1072,9 @@ int adjust_shared_perm(const char *path); /* * Create the directory containing the named path, using care to be - * somewhat safe against races. Return one of the scld_error values - * to indicate success/failure. + * somewhat safe against races. Return one of the scld_error values to + * indicate success/failure. On error, set errno to describe the + * problem. * * SCLD_VANISHED indicates that one of the ancestor directories of the * path existed at one point during the function call and then @@ -1097,6 +1098,49 @@ enum scld_error { enum scld_error safe_create_leading_directories(char *path); enum scld_error safe_create_leading_directories_const(const char *path); +/* + * Callback function for raceproof_create_file(). This function is + * expected to do something that makes dirname(path) permanent despite + * the fact that other processes might be cleaning up empty + * directories at the same time. Usually it will create a file named + * path, but alternatively it could create another file in that + * directory, or even chdir() into that directory. The function should + * return 0 if the action was completed successfully. On error, it + * should return a nonzero result and set errno. + * raceproof_create_file() treats two errno values specially: + * + * - ENOENT -- dirname(path) does not exist. In this case, + * raceproof_create_file() tries creating dirname(path) + * (and any parent directories, if necessary) and calls + * the function again. + * + * - EISDIR -- the file already exists and is a directory. In this + * case, raceproof_create_file() removes the directory if + * it is empty (and recursively any empty directories that + * it contains) and calls the function again. + * + * Any other errno causes raceproof_create_file() to fail with the + * callback's return value and errno. + * + * Obviously, this function should be OK with being called again if it + * fails with ENOENT or EISDIR. In other scenarios it will not be + * called again. + */ +typedef int create_file_fn(const char *path, void *cb); + +/* + * Create a file in dirname(path) by calling fn, creating leading + * directories if necessary. Retry a few times in case we are racing + * with another process that is trying to clean up the directory that + * contains path. See the documentation for create_file_fn for more + * details. + * + * Return the value and set the errno that resulted from the most + * recent call of fn. fn is always called at least once, and will be + * called more than once if it returns ENOENT or EISDIR. + */ +int raceproof_create_file(const char *path, create_file_fn fn, void *cb); + int mkdir_in_gitdir(const char *path); extern char *expand_user_path(const char *path); const char *enter_repo(const char *path, int strict); |