Bug 1874035 - Add custom Debug derives for bitflags with custom derives. r=gfx-reviewers,emilio,ErichDonGubler

bitflags 2 has a shortcoming with using custom derives: you can't use
custom derives (for e.g. MallocSizeOf) at the same time as bitflags's for
the derives it supports.
See bitflags/bitflags#395

Differential Revision: https://phabricator.services.mozilla.com/D199941

[ghsync] From https://hg.mozilla.org/mozilla-central/rev/45bd6cc1bf7490f80630afce7550706e9b064f81

Author: glandium

webrender/src/clip.rs

@@ -894,7 +894,7 @@ impl From<ClipItemKey> for ClipNode {
 // Flags that are attached to instances of clip nodes.
 #[cfg_attr(feature = "capture", derive(Serialize))]
 #[cfg_attr(feature = "replay", derive(Deserialize))]
-#[derive(Debug, Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash, MallocSizeOf)]
+#[derive(Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash, MallocSizeOf)]
 pub struct ClipNodeFlags(u8);
 
 bitflags! {
@@ -905,6 +905,16 @@ bitflags! {
     }
 }
 
+impl core::fmt::Debug for ClipNodeFlags {
+    fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
+        if self.is_empty() {
+            write!(f, "{:#x}", Self::empty().bits())
+        } else {
+            bitflags::parser::to_writer(self, f)
+        }
+    }
+}
+
 // When a clip node is found to be valid for a
 // clip chain instance, it's stored in an index
 // buffer style structure. This struct contains

webrender/src/gpu_types.rs

@@ -612,7 +612,7 @@ pub struct MaskInstance {
 /// code should process this instance.
 #[cfg_attr(feature = "capture", derive(Serialize))]
 #[cfg_attr(feature = "replay", derive(Deserialize))]
-#[derive(Debug, Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash, MallocSizeOf)]
+#[derive(Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash, MallocSizeOf)]
 pub struct BrushFlags(u16);
 
 bitflags! {
@@ -646,6 +646,16 @@ bitflags! {
     }
 }
 
+impl core::fmt::Debug for BrushFlags {
+    fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
+        if self.is_empty() {
+            write!(f, "{:#x}", Self::empty().bits())
+        } else {
+            bitflags::parser::to_writer(self, f)
+        }
+    }
+}
+
 /// Convenience structure to encode into PrimitiveInstanceData.
 pub struct BrushInstance {
     pub prim_header_index: PrimitiveHeaderIndex,

webrender/src/segment.rs

@@ -70,7 +70,7 @@ const MAX_SEGMENTS: usize = 64;
 /// `write_transform_vertex()` function.
 #[cfg_attr(feature = "capture", derive(Serialize))]
 #[cfg_attr(feature = "replay", derive(Deserialize))]
-#[derive(Debug, Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash, MallocSizeOf)]
+#[derive(Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash, MallocSizeOf)]
 pub struct EdgeAaSegmentMask(u8);
 
 bitflags! {
@@ -86,6 +86,16 @@ bitflags! {
     }
 }
 
+impl core::fmt::Debug for EdgeAaSegmentMask {
+    fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
+        if self.is_empty() {
+            write!(f, "{:#x}", Self::empty().bits())
+        } else {
+            bitflags::parser::to_writer(self, f)
+        }
+    }
+}
+
 bitflags! {
     #[derive(Debug, Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash)]
     pub struct ItemFlags: u8 {

webrender_api/src/display_item.rs

@@ -35,7 +35,7 @@ pub type ItemTag = (u64, u16);
 pub type ItemKey = u16;
 
 #[repr(C)]
-#[derive(Debug, Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash, Deserialize, MallocSizeOf, Serialize, PeekPoke)]
+#[derive(Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash, Deserialize, MallocSizeOf, Serialize, PeekPoke)]
 pub struct PrimitiveFlags(u8);
 
 bitflags! {
@@ -59,6 +59,16 @@ bitflags! {
     }
 }
 
+impl core::fmt::Debug for PrimitiveFlags {
+    fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
+        if self.is_empty() {
+            write!(f, "{:#x}", Self::empty().bits())
+        } else {
+            bitflags::parser::to_writer(self, f)
+        }
+    }
+}
+
 impl Default for PrimitiveFlags {
     fn default() -> Self {
         PrimitiveFlags::IS_BACKFACE_VISIBLE
@@ -933,7 +943,7 @@ impl Hash for RasterSpace {
 }
 
 #[repr(C)]
-#[derive(Debug, Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash, Deserialize, MallocSizeOf, Serialize, PeekPoke)]
+#[derive(Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash, Deserialize, MallocSizeOf, Serialize, PeekPoke)]
 pub struct StackingContextFlags(u8);
 
 bitflags! {
@@ -948,6 +958,16 @@ bitflags! {
     }
 }
 
+impl core::fmt::Debug for StackingContextFlags {
+    fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
+        if self.is_empty() {
+            write!(f, "{:#x}", Self::empty().bits())
+        } else {
+            bitflags::parser::to_writer(self, f)
+        }
+    }
+}
+
 impl Default for StackingContextFlags {
     fn default() -> Self {
         StackingContextFlags::empty()

webrender_api/src/font.rs

@@ -182,7 +182,7 @@ impl Default for GlyphOptions {
 }
 
 #[repr(C)]
-#[derive(Debug, Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash, Deserialize, MallocSizeOf, Serialize, PeekPoke)]
+#[derive(Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash, Deserialize, MallocSizeOf, Serialize, PeekPoke)]
 pub struct FontInstanceFlags(u32);
 
 bitflags! {
@@ -220,6 +220,16 @@ bitflags! {
     }
 }
 
+impl core::fmt::Debug for FontInstanceFlags {
+    fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
+        if self.is_empty() {
+            write!(f, "{:#x}", Self::empty().bits())
+        } else {
+            bitflags::parser::to_writer(self, f)
+        }
+    }
+}
+
 impl Default for FontInstanceFlags {
     #[cfg(target_os = "windows")]
     fn default() -> FontInstanceFlags {

webrender_api/src/lib.rs

@@ -595,7 +595,7 @@ pub enum IntParameter {
 
 /// Flags to track why we are rendering.
 #[repr(C)]
-#[derive(Debug, Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash, Default, Deserialize, MallocSizeOf, Serialize)]
+#[derive(Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash, Default, Deserialize, MallocSizeOf, Serialize)]
 pub struct RenderReasons(u32);
 
 bitflags! {
@@ -633,13 +633,23 @@ bitflags! {
     }
 }
 
+impl core::fmt::Debug for RenderReasons {
+    fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
+        if self.is_empty() {
+            write!(f, "{:#x}", Self::empty().bits())
+        } else {
+            bitflags::parser::to_writer(self, f)
+        }
+    }
+}
+
 impl RenderReasons {
     pub const NUM_BITS: u32 = 17;
 }
 
 /// Flags to enable/disable various builtin debugging tools.
 #[repr(C)]
-#[derive(Debug, Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash, Default, Deserialize, MallocSizeOf, Serialize)]
+#[derive(Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash, Default, Deserialize, MallocSizeOf, Serialize)]
 pub struct DebugFlags(u32);
 
 bitflags! {
@@ -713,6 +723,16 @@ bitflags! {
     }
 }
 
+impl core::fmt::Debug for DebugFlags {
+    fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
+        if self.is_empty() {
+            write!(f, "{:#x}", Self::empty().bits())
+        } else {
+            bitflags::parser::to_writer(self, f)
+        }
+    }
+}
+
 /// Information specific to a primitive type that
 /// uniquely identifies a primitive template by key.
 #[derive(Debug, Clone, Eq, MallocSizeOf, PartialEq, Hash, Serialize, Deserialize)]