- Add feature flag for XML metadata

- Introduce XmlBox enum instead of two separate fields

Author: Adrian

mp4parse/Cargo.toml

@@ -42,6 +42,7 @@ criterion = "0.3"
 
 [features]
 3gpp = []
+meta-xml = []
 
 [[bench]]
 name = "avif_benchmark"

mp4parse/src/boxes.rs

@@ -176,7 +176,9 @@ box_database!(
     MetadataItemListEntry             0x696c_7374, // "ilst"
     MetadataItemDataEntry             0x6461_7461, // "data"
     MetadataItemNameBox               0x6e61_6d65, // "name"
+    #[cfg(feature = "meta-xml")]
     MetadataXMLBox                    0x786d_6c20, // "xml "
+    #[cfg(feature = "meta-xml")]
     MetadataBXMLBox                   0x6278_6d6c, // "bxml"
     UserdataBox                       0x7564_7461, // "udta"
     AlbumEntry                        0xa961_6c62, // "©alb"

mp4parse/src/lib.rs

@@ -752,10 +752,19 @@ pub struct MetadataBox {
     pub sort_album_artist: Option<TryString>,
     /// The name of the composer to sort by 'soco'
     pub sort_composer: Option<TryString>,
+    /// Metadata
+    #[cfg(feature = "meta-xml")]
+    pub xml: Option<XmlBox>,
+}
+
+/// See ISOBMFF (ISO 14496-12:2015) § 8.11.2.1
+#[cfg(feature = "meta-xml")]
+#[derive(Debug)]
+pub enum XmlBox {
     /// XML metadata
-    pub xml: Option<TryString>,
+    StringXmlBox(TryString),
     /// Binary XML metadata
-    pub bxml: Option<TryVec<u8>>,
+    BinaryXmlBox(TryVec<u8>),
 }
 
 /// Internal data structures.
@@ -4062,15 +4071,18 @@ fn read_udta<T: Read>(src: &mut BMFFBox<T>) -> Result<UserdataBox> {
     Ok(udta)
 }
 
-/// Parse a metadata box inside a udta box
+/// Parse the meta box
+/// See ISOBMFF (ISO 14496-12:2015) § 8.111.
 fn read_meta<T: Read>(src: &mut BMFFBox<T>) -> Result<MetadataBox> {
     let (_, _) = read_fullbox_extra(src)?;
     let mut iter = src.box_iter();
     let mut meta = MetadataBox::default();
     while let Some(mut b) = iter.next_box()? {
         match b.head.name {
             BoxType::MetadataItemListEntry => read_ilst(&mut b, &mut meta)?,
+            #[cfg(feature = "meta-xml")]
             BoxType::MetadataXMLBox => read_xml_(&mut b, &mut meta)?,
+            #[cfg(feature = "meta-xml")]
             BoxType::MetadataBXMLBox => read_bxml(&mut b, &mut meta)?,
             _ => skip_box_content(&mut b)?,
         };
@@ -4080,18 +4092,24 @@ fn read_meta<T: Read>(src: &mut BMFFBox<T>) -> Result<MetadataBox> {
 }
 
 /// Parse a XML box inside a meta box
+/// See ISOBMFF (ISO 14496-12:2015) § 8.11.2
+#[cfg(feature = "meta-xml")]
 fn read_xml_<T: Read>(src: &mut BMFFBox<T>, meta: &mut MetadataBox) -> Result<()> {
-    let (_, _) = read_fullbox_extra(src)?;
-    let size = src.content.limit();
-    meta.xml = Some(read_buf(&mut src.content, size)?);
+    if read_fullbox_version_no_flags(src)? != 0 {
+        return Err(Error::Unsupported("unsupported XmlBox version"));
+    }
+    meta.xml = Some(XmlBox::StringXmlBox(src.read_into_try_vec()?));
     Ok(())
 }
 
 /// Parse a Binary XML box inside a meta box
+/// See ISOBMFF (ISO 14496-12:2015) § 8.11.2
+#[cfg(feature = "meta-xml")]
 fn read_bxml<T: Read>(src: &mut BMFFBox<T>, meta: &mut MetadataBox) -> Result<()> {
-    let (_, _) = read_fullbox_extra(src)?;
-    let size = src.content.limit();
-    meta.bxml = Some(read_buf(&mut src.content, size)?);
+    if read_fullbox_version_no_flags(src)? != 0 {
+        return Err(Error::Unsupported("unsupported XmlBox version"));
+    }
+    meta.xml = Some(XmlBox::BinaryXmlBox(src.read_into_try_vec()?));
     Ok(())
 }
 

mp4parse_capi/Cargo.toml

@@ -35,3 +35,4 @@ env_logger = "0.8"
 
 [features]
 3gpp = ["mp4parse/3gpp"]
+meta-xml = ["mp4parse/meta-xml"]

mp4parse_capi/cbindgen.toml

@@ -18,3 +18,4 @@ rename_variants = "QualifiedScreamingSnakeCase"
 
 [defines]
 "feature = 3gpp" = "MP4PARSE_FEATURE_3GPP"
+"feature = meta-xml" = "MP4PARSE_FEATURE_META_XML"