codegen: Constify enum constants.

Author: emilio

libbindgen/src/chooser.rs

@@ -19,7 +19,7 @@ pub trait TypeChooser: fmt::Debug {
     fn constify_enum_variant(&self,
                              _enum_name: Option<&str>,
                              _variant_name: &str,
-                             _variant_value: Option<EnumVariantValue>) -> bool {
+                             _variant_value: EnumVariantValue) -> bool {
         false
     }
 }

libbindgen/src/codegen/mod.rs

@@ -1,6 +1,5 @@
 mod helpers;
 
-
 use aster;
 
 use ir::annotations::FieldAccessorKind;
@@ -1667,7 +1666,22 @@ impl CodeGenerator for Enum {
             Some(&name)
         };
 
-        for variant in self.variants().iter() {
+        // NB: We defer the creation of constified variants, in case we find
+        // another variant with the same value (which is the common thing to
+        // do).
+        let mut constified_variants = vec![];
+
+        let mut iter = self.variants().iter().peekable();
+
+        while iter.peek().is_some() || !constified_variants.is_empty() {
+            let variant = iter.next()
+                .unwrap_or_else(|| constified_variants.remove(0));
+
+            if variant.force_constification() && iter.peek().is_some() {
+                constified_variants.push(variant);
+                continue;
+            }
+
             match seen_values.entry(variant.val()) {
                 Entry::Occupied(ref entry) => {
                     if is_rust_enum {
@@ -1707,9 +1721,11 @@ impl CodeGenerator for Enum {
 
                     let variant_name = ctx.rust_mangle(variant.name());
 
-                    // If it's an unnamed enum, we also generate a constant so
-                    // it can be properly accessed.
-                    if is_rust_enum && enum_ty.name().is_none() {
+                    // If it's an unnamed enum, or constification is enforced,
+                    // we also generate a constant so it can be properly
+                    // accessed.
+                    if (is_rust_enum && enum_ty.name().is_none()) ||
+                        variant.force_constification() {
                         let mangled_name = if is_toplevel {
                             variant_name.clone()
                         } else {

libbindgen/src/ir/annotations.rs

@@ -45,13 +45,18 @@ pub struct Annotations {
     ///
     /// ```cpp
     /// enum Foo {
-    ///     Bar = 0, //< <div rustbindgen constant></div>
+    ///     Bar = 0, /**< <div rustbindgen constant></div> */
     ///     Baz = 0,
     /// };
     /// ```
     ///
     /// In that case, bindgen will generate a constant for `Bar` instead of
     /// `Baz`.
+    ///
+    /// You can see the kind of comments that are accepted in the Doxygen
+    /// documentation:
+    ///
+    /// http://www.stack.nl/~dimitri/doxygen/manual/docblocks.html
     constify_enum_variant: bool,
 }
 

libbindgen/src/ir/enum_ty.rs

@@ -82,7 +82,7 @@ impl Enum {
                     let name = cursor.spelling();
                     let should_constify = ctx.type_chooser()
                         .map_or(false, |c| {
-                            c.constify_enum_variant(type_name, &name, value)
+                            c.constify_enum_variant(type_name, &name, val)
                         }) ||
                         Annotations::new(&cursor).map_or(false, |anno| {
                             anno.constify_enum_variant()

libbindgen/tests/expectations/tests/constify-enum.rs

@@ -0,0 +1,22 @@
+/* automatically generated by rust-bindgen */
+
+
+#![allow(non_snake_case)]
+
+
+pub const nsCSSPropertyID_eCSSProperty_COUNT_unexistingVariantValue:
+          nsCSSPropertyID =
+    nsCSSPropertyID::eCSSProperty_COUNT_unexistingVariantValue;
+pub const nsCSSPropertyID_eCSSProperty_COUNT: nsCSSPropertyID =
+    nsCSSPropertyID::eCSSPropertyAlias_aa;
+pub const nsCSSPropertyID_eCSSProperty_COUNT_DUMMY2: nsCSSPropertyID =
+    nsCSSPropertyID::eCSSProperty_b;
+#[repr(u32)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+pub enum nsCSSPropertyID {
+    eCSSProperty_a = 0,
+    eCSSProperty_b = 1,
+    eCSSPropertyAlias_aa = 2,
+    eCSSPropertyAlias_bb = 3,
+    eCSSProperty_COUNT_unexistingVariantValue = 4,
+}

libbindgen/tests/headers/constify-enum.h

@@ -0,0 +1,13 @@
+
+enum nsCSSPropertyID {
+  eCSSProperty_a,
+  eCSSProperty_b,
+
+  eCSSProperty_COUNT, /**< <div rustbindgen constant></div> */
+  eCSSProperty_COUNT_DUMMY2 = eCSSProperty_COUNT - 1, /**< <div rustbindgen constant></div> */
+
+  eCSSPropertyAlias_aa,
+  eCSSPropertyAlias_bb,
+
+  eCSSProperty_COUNT_unexistingVariantValue, /**< <div rustbindgen constant></div> */
+};