(MINOR) New module for XMP namespace constants (#53)

Removed `xmp_const` module in favor of `xmp_ns`, which contains constants for many common XMP namespaces.

Replace `xmp_const::XMP_NS_XMP` with `xmp_ns::XMP`.

README.md

@@ -28,6 +28,12 @@ Add this to your `Cargo.toml`:
 xmp_toolkit = "0.3.8"
 ```
 
+## Breaking changes in 0.x series
+
+### Upgrading to 0.4 from earlier releases
+
+The `xmp_const` module has been removed and a new `xmp_ns` module has been added, containing constants for many common XMP namespaces. Replace `xmp_const::XMP_NS_XMP` with `xmp_ns::XMP`.
+
 ## License
 
 The `xmp_toolkit` crate is distributed under the terms of both the MIT license and the Apache License (Version 2.0).

src/lib.rs

@@ -16,17 +16,11 @@
 #![doc = include_str!("../README.md")]
 
 mod ffi;
-
-mod xmp_const;
-pub use xmp_const::*;
-
 mod xmp_date_time;
-pub use xmp_date_time::XmpDateTime;
-
 mod xmp_file;
-pub use xmp_file::OpenFileOptions;
-pub use xmp_file::XmpFile;
-pub use xmp_file::XmpFileError;
-
 mod xmp_meta;
+pub mod xmp_ns;
+
+pub use xmp_date_time::XmpDateTime;
+pub use xmp_file::{OpenFileOptions, XmpFile, XmpFileError};
 pub use xmp_meta::XmpMeta;

src/xmp_file.rs

@@ -232,7 +232,7 @@ mod tests {
 
     use tempfile::tempdir;
 
-    use crate::{xmp_const::*, XmpDateTime};
+    use crate::{xmp_ns, XmpDateTime};
 
     fn fixture_path(name: &str) -> String {
         let root_dir = &env::var("CARGO_MANIFEST_DIR").unwrap();
@@ -278,9 +278,9 @@ mod tests {
             assert!(m.does_property_exist("http://purl.org/dc/terms/", "provenance"),);
             assert!(!m.does_property_exist("http://purl.org/dc/terms/", "provenancx"),);
 
-            if m.does_property_exist(XMP_NS_XMP, "MetadataDate") {
+            if m.does_property_exist(xmp_ns::XMP, "MetadataDate") {
                 let updated_time = XmpDateTime::current();
-                m.set_property_date(XMP_NS_XMP, "MetadataDate", &updated_time);
+                m.set_property_date(xmp_ns::XMP, "MetadataDate", &updated_time);
             }
 
             assert!(f.can_put_xmp(&m));

src/xmp_ns.rs

@@ -0,0 +1,78 @@
+// Copyright 2022 Adobe. All rights reserved.
+// This file is licensed to you under the Apache License,
+// Version 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
+// or the MIT license (http://opensource.org/licenses/MIT),
+// at your option.
+
+// Unless required by applicable law or agreed to in writing,
+// this software is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR REPRESENTATIONS OF ANY KIND, either express or
+// implied. See the LICENSE-MIT and LICENSE-APACHE files for the
+// specific language governing permissions and limitations under
+// each license.
+
+//! Standard XML namespace constants.
+
+/// The XML namespace for the XMP "basic" schema.
+pub const XMP: &str = "http://ns.adobe.com/xap/1.0/";
+
+/// The XML namespace for the XMP copyright schema.
+pub const XMP_RIGHTS: &str = "http://ns.adobe.com/xap/1.0/rights/";
+
+/// The XML namespace for the XMP digital asset management schema.
+pub const XMP_MM: &str = "http://ns.adobe.com/xap/1.0/mm/";
+
+/// The XML namespace for the job management schema.
+pub const XMP_BJ: &str = "http://ns.adobe.com/xap/1.0/bj/";
+
+/// The XML namespace for the PDF schema.
+pub const PDF: &str = "http://ns.adobe.com/pdf/1.3/";
+
+/// The XML namespace for the Photoshop custom schema.
+pub const PHOTOSHOP: &str = "http://ns.adobe.com/photoshop/1.0/";
+
+/// The XML namespace for Adobe's EXIF schema.
+pub const EXIF: &str = "http://ns.adobe.com/exif/1.0/";
+
+/// The XML namespace for Adobe's TIFF schema.
+pub const TIFF: &str = "http://ns.adobe.com/tiff/1.0/";
+
+// --- XML namespace constants for qualifiers and structured property fields ---
+
+/// The XML namespace for qualifiers of the `xmp:Identifier` property.
+pub const IDENTIFIER_QUAL: &str = "http://ns.adobe.com/xmp/Identifier/qual/1.0/";
+
+/// The XML namespace for fields of the `Dimensions` type.
+pub const DIMENSIONS: &str = "http://ns.adobe.com/xap/1.0/sType/Dimensions#";
+
+/// The XML namespace for fields of a graphical image. Used for the `Thumbnail` type.
+pub const IMAGE: &str = "http://ns.adobe.com/xap/1.0/g/img/";
+
+/// The XML namespace for fields of the `ResourceEvent` type.
+pub const RESOURCE_EVENT: &str = "http://ns.adobe.com/xap/1.0/sType/ResourceEvent#";
+
+/// The XML namespace for fields of the `ResourceRef` type.
+pub const RESOURCE_REF: &str = "http://ns.adobe.com/xap/1.0/sType/ResourceRef#";
+
+/// The XML namespace for fields of the `Version` type.
+pub const ST_VERSION: &str = "http://ns.adobe.com/xap/1.0/sType/Version#";
+
+/// The XML namespace for fields of the `JobRef` type.
+pub const ST_JOB: &str = "http://ns.adobe.com/xap/1.0/sType/Job#";
+
+// --- XML namespace constants from outside Adobe ---
+
+/// The XML namespace for the Dublin Core schema.
+pub const DC: &str = "http://purl.org/dc/elements/1.1/";
+
+/// The XML namespace for the IPTC Core schema.
+pub const IPTC_CORE: &str = "http://iptc.org/std/Iptc4xmpCore/1.0/xmlns/";
+
+/// The XML namespace for the IPTC Extension schema.
+pub const IPTC_EXT: &str = "http://iptc.org/std/Iptc4xmpExt/2008-02-29/";
+
+/// The XML namespace for RDF.
+pub const RDF: &str = "http://www.w3.org/1999/02/22-rdf-syntax-ns#";
+
+/// The XML namespace for XML.
+pub const XML: &str = "http://www.w3.org/XML/1998/namespace";