Add TemplateDeclaration::all_template_parameters

The all_template_parameters method gets the complete set of template parameters
that can affect a given item.

Note that this item doesn't need to be a template declaration itself for `Some`
to be returned from this method (in contrast to `self_template_params`). If this
item is a member of a template declaration, then the parent's template
parameters are included here. See the example in TemplateDeclaration's doc
comment for details.

1 files changed, 65 insertions, 2 deletions

diff --git a/src/ir/ty.rs b/src/ir/ty.rs
index 66136828..1b5ecc3c 100644
--- a/src/ir/ty.rs
+++ b/src/ir/ty.rs
@@ -7,7 +7,7 @@ use super::dot::DotAttributes;
 use super::enum_ty::Enum;
 use super::function::FunctionSig;
 use super::int::IntKind;
-use super::item::Item;
+use super::item::{Item, ItemAncestors};
 use super::layout::Layout;
 use super::objc::ObjCInterface;
 use super::traversal::{Trace, Tracer};
@@ -16,7 +16,40 @@ use parse::{ClangItemParser, ParseError, ParseResult};
 use std::io;
 use std::mem;
 
-/// Template declaration related methods.
+/// Template declaration (and such declaration's template parameters) related
+/// methods.
+///
+/// Consider this example:
+///
+/// ```c++
+/// template <typename T, typename U>
+/// class Foo {
+///     template <typename V>
+///     using Bar = V*;
+///
+///     class Inner {
+///         T        x;
+///         U        y;
+///         Bar<int> z;
+///     };
+/// };
+///
+/// class Qux {
+///     int y;
+/// };
+/// ```
+///
+/// The following table depicts the results of each trait method when invoked on
+/// `Foo`, `Bar`, and `Qux`.
+///
+/// +------+----------------------+--------------------------+------------------------+
+/// |Decl. | self_template_params | num_self_template_params | all_template_parameters|
+/// +------+----------------------+--------------------------+------------------------+
+/// |Foo   | Some([T, U])         | Some(2)                  | Some([T, U])           |
+/// |Bar   | Some([V])            | Some(1)                  | Some([T, U, V])        |
+/// |Inner | None                 | None                     | Some([T, U])           |
+/// |Qux   | None                 | None                     | None                   |
+/// +------+----------------------+--------------------------+------------------------+
 pub trait TemplateDeclaration {
     /// Get the set of `ItemId`s that make up this template declaration's free
     /// template parameters.
@@ -38,6 +71,36 @@ pub trait TemplateDeclaration {
     fn num_self_template_params(&self, ctx: &BindgenContext) -> Option<usize> {
         self.self_template_params(ctx).map(|params| params.len())
     }
+
+    /// Get the complete set of template parameters that can affect this
+    /// declaration.
+    ///
+    /// Note that this item doesn't need to be a template declaration itself for
+    /// `Some` to be returned here (in contrast to `self_template_params`). If
+    /// this item is a member of a template declaration, then the parent's
+    /// template parameters are included here.
+    ///
+    /// In the example above, `Inner` depends on both of the `T` and `U` type
+    /// parameters, even though it is not itself a template declaration and
+    /// therefore has no type parameters itself. Perhaps it helps to think about
+    /// how we would fully reference such a member type in C++:
+    /// `Foo<int,char>::Inner`. `Foo` *must* be instantiated with template
+    /// arguments before we can gain access to the `Inner` member type.
+    fn all_template_params(&self, ctx: &BindgenContext) -> Option<Vec<ItemId>>
+        where Self: ItemAncestors
+    {
+        let each_self_params: Vec<Vec<_>> = self.ancestors(ctx)
+            .filter_map(|id| id.self_template_params(ctx))
+            .collect();
+        if each_self_params.is_empty() {
+            None
+        } else {
+            Some(each_self_params.into_iter()
+                 .rev()
+                 .flat_map(|params| params)
+                 .collect())
+        }
+    }
 }
 
 /// The base representation of a type in bindgen.