Implement the MediaPermissions dictonary

examples/video.rs

@@ -145,7 +145,7 @@ fn main() -> std::io::Result<()> {
         media_clip.data_url(Str(file_url));
     }
     media_clip.data_type(Str(b"video/mp4"));
-    media_clip.temp_file(Str(b"TEMPACCESS"));
+    media_clip.permissions().temp_file(Str(b"TEMPACCESS"));
     media_clip.finish();
 
     // Add controls for the media player.

src/lib.rs

@@ -135,7 +135,7 @@ pub mod writers {
         ExponentialFunction, PostScriptFunction, SampledFunction, StitchingFunction,
     };
     pub use object::{NameTree, NameTreeEntries, NumberTree, NumberTreeEntries};
-    pub use renditions::{Rendition, MediaClip, MediaPlayParams};
+    pub use renditions::{Rendition, MediaClip, MediaPlayParams, MediaPermissions};
     pub use structure::{
         Catalog, ClassMap, Destination, DeveloperExtension, DocumentInfo, MarkInfo,
         MarkedRef, Metadata, Names, ObjectRef, Outline, OutlineItem, Page, PageLabel,

src/renditions.rs

@@ -86,16 +86,9 @@ impl<'a> MediaClip<'a> {
         self
     }
 
-    /// Write the `/TF` attribute inside the `/P` dictionary controlling the
-    /// permissions to write a temporary file.
-    ///
-    /// The media permissions dictionary has a single entry. Thus, skip
-    /// implementing a full MediaPermissions dictionary object.
-    pub fn temp_file(&mut self, tf: Str) -> &mut Self {
-        self.insert(Name(b"P")).dict()
-                               .pair(Name(b"Type"), Name(b"MediaPermissions"))
-                               .pair(Name(b"TF"), tf);
-        self
+    /// Start writing the `/P`, i.e. media permissions, dictionary.
+    pub fn permissions(&mut self) -> MediaPermissions<'_> {
+        self.insert(Name(b"P")).start()
     }
 }
 
@@ -131,6 +124,30 @@ impl<'a> MediaPlayParams<'a> {
 deref!('a, MediaPlayParams<'a> => Dict<'a>, dict);
 
 
+/// Writer for an _media permissions dictionary_.
+///
+/// This struct is created by [`Rendition::permissions`].
+pub struct MediaPermissions<'a> {
+    dict: Dict<'a>,
+}
+
+writer!(MediaPermissions: |obj| {
+    let mut dict = obj.dict();
+    dict.pair(Name(b"Type"), Name(b"MediaPermissions"));
+    Self { dict }
+});
+
+impl<'a> MediaPermissions<'a> {
+    /// Write the `/TF` attribute to control permissions to write a temporary file.
+    pub fn temp_file(&mut self, tf: Str) -> &mut Self {
+        self.pair(Name(b"TF"), tf);
+        self
+    }
+}
+
+deref!('a, MediaPermissions<'a> => Dict<'a>, dict);
+
+
 /// Type of rendition objects.
 #[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
 pub enum RenditionType {