codegen: Constify enum variants.

6 files changed, 62 insertions, 9 deletions

diff --git a/libbindgen/src/chooser.rs b/libbindgen/src/chooser.rs
index f28b32f1..660f423c 100644
--- a/libbindgen/src/chooser.rs
+++ b/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
     }
 }
diff --git a/libbindgen/src/codegen/mod.rs b/libbindgen/src/codegen/mod.rs
index 24b862be..e4dbbd8f 100644
--- a/libbindgen/src/codegen/mod.rs
+++ b/libbindgen/src/codegen/mod.rs
@@ -1,6 +1,5 @@
 mod helpers;
 
-
 use aster;
 
 use ir::annotations::FieldAccessorKind;
@@ -21,7 +20,7 @@ use self::helpers::{BlobTyBuilder, attributes};
 
 use std::borrow::Cow;
 use std::cell::Cell;
-use std::collections::HashSet;
+use std::collections::{HashSet, VecDeque};
 use std::collections::hash_map::{Entry, HashMap};
 use std::fmt::Write;
 use std::iter;
@@ -1667,7 +1666,19 @@ 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 = VecDeque::new();
+
+        let mut iter = self.variants().iter().peekable();
+        while let Some(variant) = iter.next().or_else(|| constified_variants.pop_front()) {
+
+            if variant.force_constification() && iter.peek().is_some() {
+                constified_variants.push_back(variant);
+                continue;
+            }
+
             match seen_values.entry(variant.val()) {
                 Entry::Occupied(ref entry) => {
                     if is_rust_enum {
@@ -1707,9 +1718,11 @@ 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 {
diff --git a/libbindgen/src/ir/annotations.rs b/libbindgen/src/ir/annotations.rs
index 70f66051..6ae350cb 100644
--- a/libbindgen/src/ir/annotations.rs
+++ b/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,
 }
 
diff --git a/libbindgen/src/ir/enum_ty.rs b/libbindgen/src/ir/enum_ty.rs
index 0c20b266..7d6d1a6e 100644
--- a/libbindgen/src/ir/enum_ty.rs
+++ b/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()
diff --git a/libbindgen/tests/expectations/tests/constify-enum.rs b/libbindgen/tests/expectations/tests/constify-enum.rs
new file mode 100644
index 00000000..356aaa05
--- /dev/null
+++ b/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,
+}
diff --git a/libbindgen/tests/headers/constify-enum.h b/libbindgen/tests/headers/constify-enum.h
new file mode 100644
index 00000000..f2771e59
--- /dev/null
+++ b/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> */
+};