From ed44a19e5ef7c0fa056b2104aee3a195c3375b2d Mon Sep 17 00:00:00 2001
From: Pat Hickey <pat@moreproductive.org>
Date: Mon, 11 Jan 2021 18:20:57 -0800
Subject: [PATCH] wiggle: use bitflags to generate flags

more consistient with the rest of the ecosystem.
---
 crates/wiggle/generate/src/types/flags.rs | 93 +++--------------------
 crates/wiggle/tests/flags.rs              |  8 +-
 2 files changed, 15 insertions(+), 86 deletions(-)

diff --git a/crates/wiggle/generate/src/types/flags.rs b/crates/wiggle/generate/src/types/flags.rs
index f87261abca..cda13a2bfa 100644
--- a/crates/wiggle/generate/src/types/flags.rs
+++ b/crates/wiggle/generate/src/types/flags.rs
@@ -27,102 +27,31 @@ pub(super) fn define_flags(names: &Names, name: &witx::Id, f: &witx::FlagsDataty
     }
 
     quote! {
-        #[repr(transparent)]
-        #[derive(Copy, Clone, Debug, ::std::hash::Hash, Eq, PartialEq)]
-        pub struct #ident(#repr);
-
-        impl #ident {
-            #(pub const #names_: #ident = #ident(#values_);)*
-
-            #[inline]
-            pub const fn empty() -> Self {
-                #ident(0)
-            }
-
-            #[inline]
-            pub const fn all() -> Self {
-                #ident(#(#values_)|*)
-            }
-
-            #[inline]
-            pub fn contains(&self, other: &#ident) -> bool {
-                !*self & *other == Self::empty()
+        #rt::bitflags::bitflags! {
+            pub struct #ident: #repr {
+                #(const #names_ = #values_;)*
             }
         }
 
         impl ::std::fmt::Display for #ident {
             fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
-                let mut first = true;
-                #(
-                    if self.0 & #values_ == #values_ {
-                        if !first {
-                            f.write_str("|")?;
-                        }
-                        first = false;
-                        f.write_fmt(format_args!("{}", stringify!(#names_).to_lowercase()))?;
-                    }
-                )*
-                if first {
-                    f.write_str("empty")?;
-                }
-                f.write_fmt(format_args!(" ({:#x})", self.0))?;
+                f.write_str(stringify!(#ident))?;
+                f.write_str("(")?;
+                ::std::fmt::Debug::fmt(self, f)?;
+                f.write_str(" (0x")?;
+                ::std::fmt::LowerHex::fmt(&self.bits, f)?;
+                f.write_str("))")?;
                 Ok(())
             }
         }
 
-        impl ::std::ops::BitAnd for #ident {
-            type Output = Self;
-            fn bitand(self, rhs: Self) -> Self::Output {
-                #ident(self.0 & rhs.0)
-            }
-        }
-
-        impl ::std::ops::BitAndAssign for #ident {
-            fn bitand_assign(&mut self, rhs: Self) {
-                *self = *self & rhs
-            }
-        }
-
-        impl ::std::ops::BitOr for #ident {
-            type Output = Self;
-            fn bitor(self, rhs: Self) -> Self::Output {
-                #ident(self.0 | rhs.0)
-            }
-        }
-
-        impl ::std::ops::BitOrAssign for #ident {
-            fn bitor_assign(&mut self, rhs: Self) {
-                *self = *self | rhs
-            }
-        }
-
-        impl ::std::ops::BitXor for #ident {
-            type Output = Self;
-            fn bitxor(self, rhs: Self) -> Self::Output {
-                #ident(self.0 ^ rhs.0)
-            }
-        }
-
-        impl ::std::ops::BitXorAssign for #ident {
-            fn bitxor_assign(&mut self, rhs: Self) {
-                *self = *self ^ rhs
-            }
-        }
-
-        impl ::std::ops::Not for #ident {
-            type Output = Self;
-            fn not(self) -> Self::Output {
-                #ident(!self.0)
-            }
-        }
-
         impl ::std::convert::TryFrom<#repr> for #ident {
             type Error = #rt::GuestError;
             fn try_from(value: #repr) -> Result<Self, #rt::GuestError> {
                 if #repr::from(!#ident::all()) & value != 0 {
                     Err(#rt::GuestError::InvalidFlagValue(stringify!(#ident)))
                 } else {
-                    Ok(#ident(value))
+                    Ok(#ident { bits: value })
                 }
             }
         }
@@ -136,7 +65,7 @@ pub(super) fn define_flags(names: &Names, name: &witx::Id, f: &witx::FlagsDataty
 
         impl From<#ident> for #repr {
             fn from(e: #ident) -> #repr {
-                e.0
+                e.bits
             }
         }
 
diff --git a/crates/wiggle/tests/flags.rs b/crates/wiggle/tests/flags.rs
index e12b64a457..1a2bb0019f 100644
--- a/crates/wiggle/tests/flags.rs
+++ b/crates/wiggle/tests/flags.rs
@@ -103,11 +103,11 @@ proptest! {
 #[test]
 fn flags_fmt() {
     let empty = format!("{}", types::CarConfig::empty());
-    assert_eq!(empty, "empty (0x0)");
+    assert_eq!(empty, "CarConfig((empty) (0x0))");
     let one_flag = format!("{}", types::CarConfig::AWD);
-    assert_eq!(one_flag, "awd (0x2)");
+    assert_eq!(one_flag, "CarConfig(AWD (0x2))");
     let two_flags = format!("{}", types::CarConfig::AUTOMATIC | types::CarConfig::SUV);
-    assert_eq!(two_flags, "automatic|suv (0x5)");
+    assert_eq!(two_flags, "CarConfig(AUTOMATIC | SUV (0x5))");
     let all = format!("{}", types::CarConfig::all());
-    assert_eq!(all, "automatic|awd|suv (0x7)");
+    assert_eq!(all, "CarConfig(AUTOMATIC | AWD | SUV (0x7))");
 }