Add toggle for prepending enum name to variant

Currently the name of a enum is always prepended to the beginning of a const or bitfield like variant. This can result in some quite unintuivite naming, if the library already prefixes its variants. For example hundreds of variants are named like this `cs_arch_CS_ARCH_ARM` when binding to the capstone library.

This commit introduces a toggle for prepending the `cs_arch_` part. By default it is enabled to preserve current behaviour. It can be toggled with the `prepend_enum_name` function on the Builder.

2 files changed, 17 insertions, 3 deletions

diff --git a/src/codegen/mod.rs b/src/codegen/mod.rs
index 46b0a3e7..120acefa 100644
--- a/src/codegen/mod.rs
+++ b/src/codegen/mod.rs
@@ -1993,10 +1993,14 @@ impl CodeGenerator for Enum {
             Some(item.parent_id().canonical_name(ctx))
         };
 
-        let constant_mangling_prefix = if enum_ty.name().is_none() {
-            parent_canonical_name.as_ref().map(|n| &*n)
+        let constant_mangling_prefix = if ctx.options().prepend_enum_name {
+            if enum_ty.name().is_none() {
+                parent_canonical_name.as_ref().map(|n| &*n)
+            } else {
+                Some(&name)
+            }
         } else {
-            Some(&name)
+            None
         };
 
         // NB: We defer the creation of constified variants, in case we find
diff --git a/src/lib.rs b/src/lib.rs
index 94a13c61..5e14d81e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -458,6 +458,12 @@ impl Builder {
         self
     }
 
+    /// Prepend the enum name to constant or bitfield variants.
+    pub fn prepend_enum_name(mut self, doit: bool) -> Self {
+        self.options.prepend_enum_name = doit;
+        self
+    }
+
     /// Generate the Rust bindings using the options built up thus far.
     pub fn generate<'ctx>(self) -> Result<Bindings<'ctx>, ()> {
         Bindings::generate(self.options, None)
@@ -593,6 +599,9 @@ pub struct BindgenOptions {
     ///
     /// [1]: https://github.com/servo/rust-bindgen/issues/528
     pub enable_mangling: bool,
+
+    /// Whether to prepend the enum name to bitfield or constant variants.
+    pub prepend_enum_name: bool,
 }
 
 /// TODO(emilio): This is sort of a lie (see the error message that results from
@@ -648,6 +657,7 @@ impl Default for BindgenOptions {
             whitelist_recursively: true,
             objc_extern_crate: false,
             enable_mangling: true,
+            prepend_enum_name: true,
         }
     }
 }