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zdir (3) Linux Manual Page

ByLinux Manual Posted on Updated on

zdir – work with file-system directories

Synopsis

//  Create a new directory item that loads in the full tree of the specified
//  path, optionally located under some parent path. If parent is "-", then
//  loads only the top-level directory, and does not use parent as a path.
CZMQ_EXPORT zdir_t *
zdir_new(const char *path, const char *parent);

//  Destroy a directory tree and all children it contains.
CZMQ_EXPORT void
zdir_destroy(zdir_t **self_p);

//  Return directory path
CZMQ_EXPORT const char *
zdir_path(zdir_t *self);

//  Return last modification time for directory.
CZMQ_EXPORT time_t
zdir_modified(zdir_t *self);

//  Return total hierarchy size, in bytes of data contained in all files
//  in the directory tree.
CZMQ_EXPORT off_t
zdir_cursize(zdir_t *self);

//  Return directory count
CZMQ_EXPORT size_t
zdir_count(zdir_t *self);

//  Returns a sorted list of zfile objects; Each entry in the list is a pointer
//  to a zfile_t item already allocated in the zdir tree. Do not destroy the
//  original zdir tree until you are done with this list.
//  The caller is responsible for destroying the return value when finished with it.
CZMQ_EXPORT zlist_t *
zdir_list(zdir_t *self);

//  Remove directory, optionally including all files that it contains, at
//  all levels. If force is false, will only remove the directory if empty.
//  If force is true, will remove all files and all subdirectories.
CZMQ_EXPORT void
zdir_remove(zdir_t *self, bool force);

//  Calculate differences between two versions of a directory tree.
//  Returns a list of zdir_patch_t patches. Either older or newer may
//  be null, indicating the directory is empty/absent. If alias is set,
//  generates virtual filename (minus path, plus alias).
//  The caller is responsible for destroying the return value when finished with it.
CZMQ_EXPORT zlist_t *
zdir_diff(zdir_t *older, zdir_t *newer, const char *alias);

//  Return full contents of directory as a zdir_patch list.
//  The caller is responsible for destroying the return value when finished with it.
CZMQ_EXPORT zlist_t *
zdir_resync(zdir_t *self, const char *alias);

//  Load directory cache; returns a hash table containing the SHA-1 digests
//  of every file in the tree. The cache is saved between runs in .cache.
//  The caller is responsible for destroying the return value when finished with it.
CZMQ_EXPORT zhash_t *
zdir_cache(zdir_t *self);

//  Print contents of directory to open stream
CZMQ_EXPORT void
zdir_fprint(zdir_t *self, FILE *file, int indent);

//  Print contents of directory to stdout
CZMQ_EXPORT void
zdir_print(zdir_t *self, int indent);

//  Create a new zdir_watch actor instance:
//
//      zactor_t *watch = zactor_new (zdir_watch, NULL);
//
//  Destroy zdir_watch instance:
//
//      zactor_destroy (&watch);
//
//  Enable verbose logging of commands and activity:
//
//      zstr_send (watch, "VERBOSE");
//
//  Subscribe to changes to a directory path:
//
//      zsock_send (watch, "ss", "SUBSCRIBE", "directory_path");
//
//  Unsubscribe from changes to a directory path:
//
//      zsock_send (watch, "ss", "UNSUBSCRIBE", "directory_path");
//
//  Receive directory changes:
//      zsock_recv (watch, "sp", &path, &patches);
//
//      // Delete the received data.
//      free (path);
//      zlist_destroy (&patches);
CZMQ_EXPORT void
zdir_watch(zsock_t *pipe, void *unused);

//  Self test of this class.
CZMQ_EXPORT void
zdir_test(bool verbose);

Description

The zdir class gives access to the file system index. It will load a directory tree (a directory plus all child directories) into a zdir structure and then let you navigate that structure. It exists mainly to wrap non-portable OS functions to do this.

Please add @discuss section in ../src/zdir.c.

Example

From zdir_test method. 

zdir_t *older = zdir_new(".", NULL);
assert(older);
if (verbose) {
    printf("
");
    zdir_dump(older, 0);
}
zdir_t *newer = zdir_new("..", NULL);
assert(newer);
zlist_t *patches = zdir_diff(older, newer, "/");
assert(patches);
while (zlist_size(patches)) {
    zdir_patch_t *patch = (zdir_patch_t *)zlist_pop(patches);
    zdir_patch_destroy(&patch);
}
zlist_destroy(&patches);
zdir_destroy(&older);
zdir_destroy(&newer);

zdir_t *nosuch = zdir_new("does-not-exist", NULL);
assert(nosuch == NULL);

// zdir_watch test:
zactor_t *watch = zactor_new(zdir_watch, NULL);
assert(watch);

if (verbose) {
    zsock_send(watch, "s", "VERBOSE");
    assert(zsock_wait(watch) == 0);
}

// need to create a file in the test directory we're watching
// in order to ensure the directory exists
zfile_t *initfile = zfile_new("./zdir-test-dir", "initial_file");
assert(initfile);
zfile_output(initfile);
fprintf(zfile_handle(initfile), "initial file
");
zfile_close(initfile);
zfile_destroy(&initfile);

zclock_sleep(1001); // wait for initial file to become 'stable'

zsock_send(watch, "si", "TIMEOUT", 100);
assert(zsock_wait(watch) == 0);

zsock_send(watch, "ss", "SUBSCRIBE", "zdir-test-dir");
assert(zsock_wait(watch) == 0);

zsock_send(watch, "ss", "UNSUBSCRIBE", "zdir-test-dir");
assert(zsock_wait(watch) == 0);

zsock_send(watch, "ss", "SUBSCRIBE", "zdir-test-dir");
assert(zsock_wait(watch) == 0);

zfile_t *newfile = zfile_new("zdir-test-dir", "test_abc");
zfile_output(newfile);
fprintf(zfile_handle(newfile), "test file
");
zfile_close(newfile);

zpoller_t *watch_poll = zpoller_new(watch, NULL);

// poll for a certain timeout before giving up and failing the test.
assert(zpoller_wait(watch_poll, 1001) == watch);

// wait for notification of the file being added
char *path;
int rc = zsock_recv(watch, "sp", &path, &patches);
assert(rc == 0);

assert(streq(path, "zdir-test-dir"));
free(path);

assert(zlist_size(patches) == 1);

zdir_patch_t *patch = (zdir_patch_t *)zlist_pop(patches);
assert(streq(zdir_patch_path(patch), "zdir-test-dir"));

zfile_t *patch_file = zdir_patch_file(patch);
assert(streq(zfile_filename(patch_file, ""), "zdir-test-dir/test_abc"));

zdir_patch_destroy(&patch);
zlist_destroy(&patches);

// remove the file
zfile_remove(newfile);
zfile_destroy(&newfile);

// poll for a certain timeout before giving up and failing the test.
assert(zpoller_wait(watch_poll, 1001) == watch);

// wait for notification of the file being removed
rc = zsock_recv(watch, "sp", &path, &patches);
assert(rc == 0);

assert(streq(path, "zdir-test-dir"));
free(path);

assert(zlist_size(patches) == 1);

patch = (zdir_patch_t *)zlist_pop(patches);
assert(streq(zdir_patch_path(patch), "zdir-test-dir"));

patch_file = zdir_patch_file(patch);
assert(streq(zfile_filename(patch_file, ""), "zdir-test-dir/test_abc"));

zdir_patch_destroy(&patch);
zlist_destroy(&patches);

zpoller_destroy(&watch_poll);
zactor_destroy(&watch);

// clean up by removing the test directory.
zdir_t *testdir = zdir_new("zdir-test-dir", NULL);
zdir_remove(testdir, true);
zdir_destroy(&testdir);

Authors

The czmq manual was written by the authors in the AUTHORS file.

Resources

Main web site: m[blue]m[]

Report bugs to the email <m[blue]zeromq-dev [at] lists.zeromq.orgm[][1]>

Copyright

Copyright (c) 1991-2012 iMatix Corporation — http://www.imatix.com Copyright other contributors as noted in the AUTHORS file. This file is part of CZMQ, the high-level C binding for 0MQ: http://czmq.zeromq.org This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0. If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/. LICENSE included with the czmq distribution.

Notes

1.

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mailto:zeromq-dev [at] lists.zeromq.org

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