1 /**
2 * This file Copyright (c) 2015-2016 Magnolia International
3 * Ltd. (http://www.magnolia-cms.com). All rights reserved.
4 *
5 *
6 * This file is dual-licensed under both the Magnolia
7 * Network Agreement and the GNU General Public License.
8 * You may elect to use one or the other of these licenses.
9 *
10 * This file is distributed in the hope that it will be
11 * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
12 * implied warranty of MERCHANTABILITY or FITNESS FOR A
13 * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
14 * Redistribution, except as permitted by whichever of the GPL
15 * or MNA you select, is prohibited.
16 *
17 * 1. For the GPL license (GPL), you can redistribute and/or
18 * modify this file under the terms of the GNU General
19 * Public License, Version 3, as published by the Free Software
20 * Foundation. You should have received a copy of the GNU
21 * General Public License, Version 3 along with this program;
22 * if not, write to the Free Software Foundation, Inc., 51
23 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
24 *
25 * 2. For the Magnolia Network Agreement (MNA), this file
26 * and the accompanying materials are made available under the
27 * terms of the MNA which accompanies this distribution, and
28 * is available at http://www.magnolia-cms.com/mna.html
29 *
30 * Any modifications to this file must keep this entire header
31 * intact.
32 *
33 */
34 package info.magnolia.resourceloader.file;
35
36 import info.magnolia.dirwatch.WatcherCallback;
37 import info.magnolia.resourceloader.Resource;
38 import info.magnolia.resourceloader.ResourceStub;
39 import info.magnolia.resourceloader.util.PredicatedResourceVisitor;
40 import info.magnolia.resourceloader.util.ResourceTreeWalker;
41
42 import java.nio.file.Files;
43 import java.nio.file.Path;
44
45 import com.google.common.base.Function;
46 import com.google.common.base.Predicate;
47
48 /**
49 * A {@link WatcherCallback} which dispatches file system modification events via {@link Function a callback}.
50 */
51 class FileWatcherCallback implements WatcherCallback {
52 private final FileSystemResourceOrigin origin;
53 private final Predicate<Path> watchedPathFilter;
54 private final Function<Resource, Void> modificationCallback;
55
56 FileWatcherCallback(FileSystemResourceOrigin origin, Predicate<Path> watchedPathFilter, Function<Resource, Void> modificationCallback) {
57 this.origin = origin;
58 this.watchedPathFilter = watchedPathFilter;
59 this.modificationCallback = modificationCallback;
60 }
61
62 /**
63 * Contents of the added folders are recursively handled in the same fashion. This is done due to the fact
64 * that only a single event is generated by the file system when a file/folder is added.
65 *
66 * @see <a href="https://jira.magnolia-cms.com/browse/MAGNOLIA-6278">MAGNOLIA-6278</a>
67 */
68 @Override
69 public void added(Path path) {
70 dispatchResourceChange(path, true);
71 }
72
73 /**
74 * Resource modifications are handled non-recursively since:
75 * - the case of a mere file is essentially non-recursive
76 * - most of the folder modification events are generated in addition to content structure modification (file/sub-directory removed/added).
77 * and => do not need additional care (even can be ignored)
78 */
79 @Override
80 public void modified(Path path) {
81 dispatchResourceChange(path, false);
82 }
83
84 /**
85 * To be consistent with the logic of {@link #added(Path)} - contents of the removed folders have to be handled recursively as well.
86 * The bad thing is that by the time the folder deletion event is processed - its contents become non-resolvable and => cannot be easily traversed.
87 * TODO - recursive traversal strategy has to be revised (probably subscribers should do that on their own).
88 */
89 @Override
90 public void removed(Path path) {
91 dispatchResourceChange(path, false);
92 }
93
94 /**
95 * Communicate file system resource changes via {@link #modificationCallback callback}.
96 *
97 * @param handleDirectoryContents indicates whether directory contents should be communicated (recursively) as well
98 */
99 protected void dispatchResourceChange(Path changedResourcePath, boolean handleDirectoryContents) {
100 if (!watchedPathFilter.apply(changedResourcePath)) {
101 return;
102 }
103
104 final FileSystemResource resource;
105
106 if (Files.exists(changedResourcePath)) {
107 resource = origin.newResource(changedResourcePath);
108 } else {
109 // Resource has been deleted - notify the subscribers via a stub
110 modificationCallback.apply(ResourceStub.withPath(changedResourcePath.toString()));
111 return;
112 }
113
114 if (Files.isRegularFile(changedResourcePath)) {
115 modificationCallback.apply(resource);
116 } else if (handleDirectoryContents && Files.isDirectory(changedResourcePath)) {
117 // Use the same path filter for resources as for the file system paths
118 final Predicate<Resource> watchedResourceFilter = new Predicate<Resource>() {
119 @Override
120 public boolean apply(Resource res) {
121 return watchedPathFilter.apply(((FileSystemResource) res).getRealPath());
122 }
123 };
124
125 new ResourceTreeWalker(PredicatedResourceVisitor.with(watchedResourceFilter, modificationCallback)).traverse(resource);
126 }
127 }
128 }