swf: Use bitflags for FileAttributes

ruffle-rs · May 22, 2021 · 8960414 · 8960414
1 parent aacdcc4
commit 8960414
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Showing 6 changed files with 33 additions and 41 deletions.
diff --git a/core/src/display_object/movie_clip.rs b/core/src/display_object/movie_clip.rs
@@ -249,7 +249,7 @@ impl<'gc> MovieClip<'gc> {
         let tag_callback = |reader: &mut SwfStream<'_>, tag_code, tag_len| match tag_code {
             TagCode::FileAttributes => {
                 let attributes = reader.read_file_attributes()?;
-                let avm_type = if attributes.is_action_script_3 {
+                let avm_type = if attributes.contains(swf::FileAttributes::IS_ACTION_SCRIPT_3) {
                     log::warn!("This SWF contains ActionScript 3 which is not yet supported by Ruffle. The movie may not work as intended.");
                     AvmType::Avm2
                 } else {

diff --git a/core/src/library.rs b/core/src/library.rs
@@ -424,7 +424,11 @@ impl<'gc> Library<'gc> {
                         if TagCode::from_u16(tag_code) == Some(TagCode::FileAttributes) =>
                     {
                         match reader.read_file_attributes() {
-                            Ok(attributes) if attributes.is_action_script_3 => AvmType::Avm2,
+                            Ok(attributes)
+                                if attributes.contains(swf::FileAttributes::IS_ACTION_SCRIPT_3) =>
+                            {
+                                AvmType::Avm2
+                            }
                             Ok(_) => AvmType::Avm1,
                             Err(e) => {
                                 log::error!("Got {} when reading FileAttributes", e);

diff --git a/swf/src/read.rs b/swf/src/read.rs
@@ -1848,13 +1848,7 @@ impl<'a> Reader<'a> {
 
     pub fn read_file_attributes(&mut self) -> Result<FileAttributes> {
         let flags = self.read_u32()?;
-        Ok(FileAttributes {
-            use_direct_blit: (flags & 0b01000000) != 0,
-            use_gpu: (flags & 0b00100000) != 0,
-            has_metadata: (flags & 0b00010000) != 0,
-            is_action_script_3: (flags & 0b00001000) != 0,
-            use_network_sandbox: (flags & 0b00000001) != 0,
-        })
+        Ok(FileAttributes::from_bits_truncate(flags as u8))
     }
 
     pub fn read_export_assets(&mut self) -> Result<ExportAssets<'a>> {

diff --git a/swf/src/test_data.rs b/swf/src/test_data.rs
@@ -1974,13 +1974,7 @@ pub fn tag_tests() -> Vec<TagTestData> {
         ),
         (
             8,
-            Tag::FileAttributes(FileAttributes {
-                use_direct_blit: false,
-                use_gpu: true,
-                has_metadata: false,
-                is_action_script_3: true,
-                use_network_sandbox: false,
-            }),
+            Tag::FileAttributes(FileAttributes::USE_GPU | FileAttributes::IS_ACTION_SCRIPT_3),
             vec![0b01_000100, 0b00010001, 0b00101000, 0, 0, 0],
         ),
         (

diff --git a/swf/src/types.rs b/swf/src/types.rs
@@ -368,13 +368,29 @@ pub enum Language {
     TraditionalChinese,
 }
 
-#[derive(Debug, PartialEq)]
-pub struct FileAttributes {
-    pub use_direct_blit: bool,
-    pub use_gpu: bool,
-    pub has_metadata: bool,
-    pub is_action_script_3: bool,
-    pub use_network_sandbox: bool,
+bitflags! {
+    /// Flags that define various characteristic of an SWF file.
+    ///
+    /// [SWF19 pp.57-58 ClipEvent](https://www.adobe.com/content/dam/acom/en/devnet/pdf/swf-file-format-spec.pdf#page=47)
+    pub struct FileAttributes: u8 {
+        /// Whether this SWF requests hardware acceleration to blit to the screen.
+        const USE_DIRECT_BLIT = 1 << 6;
+
+        /// Whether this SWF requests hardware acceleration for compositing.
+        const USE_GPU = 1 << 5;
+
+        /// Whether this SWF contains XMP metadata in a Metadata tag.
+        const HAS_METADATA = 1 << 4;
+
+        /// Whether this SWF uses ActionScript 3 (AVM2).
+        const IS_ACTION_SCRIPT_3 = 1 << 3;
+
+        /// Whether this SWF should be placed in the network sandbox when run locally.
+        ///
+        /// SWFs in the network sandbox can only access network resources,  not local resources.
+        /// SWFs in the local sandbox can only access local resources, not network resources.
+        const USE_NETWORK_SANDBOX = 1 << 0;
+    }
 }
 
 #[derive(Debug, PartialEq)]

diff --git a/swf/src/write.rs b/swf/src/write.rs
@@ -979,25 +979,9 @@ impl<W: Write> Writer<W> {
                 self.output.write_all(&frame.data)?;
             }
 
-            Tag::FileAttributes(ref attributes) => {
+            Tag::FileAttributes(attributes) => {
                 self.write_tag_header(TagCode::FileAttributes, 4)?;
-                let mut flags = 0u32;
-                if attributes.use_direct_blit {
-                    flags |= 0b01000000;
-                }
-                if attributes.use_gpu {
-                    flags |= 0b00100000;
-                }
-                if attributes.has_metadata {
-                    flags |= 0b00010000;
-                }
-                if attributes.is_action_script_3 {
-                    flags |= 0b00001000;
-                }
-                if attributes.use_network_sandbox {
-                    flags |= 0b00000001;
-                }
-                self.write_u32(flags)?;
+                self.write_u32(attributes.bits() as u32)?;
             }
 
             Tag::FrameLabel(FrameLabel { label, is_anchor }) => {