bpf_dsl: Move {Bool,Result}ExprImpl definition into separate header

sandbox/linux/bpf_dsl/bpf_dsl.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef SANDBOX_LINUX_BPF_DSL_BPF_DSL_H_
 #define SANDBOX_LINUX_BPF_DSL_BPF_DSL_H_
 
 #include <stdint.h>
 
 #include <utility>
@@ skipping 264 matching lines @@
     const __typeof__(value) bpf_dsl_cases_values[] = {value, __VA_ARGS__}; \
     std::vector<__typeof__(value)>(                                        \
         bpf_dsl_cases_values,                                              \
         bpf_dsl_cases_values + arraysize(bpf_dsl_cases_values));           \
   })
 
 // =====================================================================
 // Official API ends here.
 // =====================================================================
 
-// Definitions below are necessary here only for C++03 compatibility.
-// Once C++11 is available, they should be moved into bpf_dsl.cc via extern
-// templates.
 namespace internal {
 
 // Make argument-dependent lookup work.  This is necessary because although
 // BoolExpr is defined in bpf_dsl, since it's merely a typedef for
 // scoped_refptr<const internal::BoolExplImpl>, argument-dependent lookup only
 // searches the "internal" nested namespace.
 using bpf_dsl::operator!;
 using bpf_dsl::operator||;
 using bpf_dsl::operator&&;
 
 // Returns a boolean expression that represents whether system call
 // argument |num| of size |size| is equal to |val|, when masked
 // according to |mask|.  Users should use the Arg template class below
 // instead of using this API directly.
 SANDBOX_EXPORT BoolExpr
     ArgEq(int num, size_t size, uint64_t mask, uint64_t val);
 
 // Returns the default mask for a system call argument of the specified size.
 SANDBOX_EXPORT uint64_t DefaultMask(size_t size);
 
-// Internal interface implemented by BoolExpr implementations.
-class SANDBOX_EXPORT BoolExprImpl : public base::RefCounted<BoolExprImpl> {
- public:
-  BoolExprImpl() {}
-  virtual ErrorCode Compile(SandboxBPF* sb,
-                            ErrorCode true_ec,
-                            ErrorCode false_ec) const = 0;
-
- protected:
-  virtual ~BoolExprImpl() {}
-
- private:
-  friend class base::RefCounted<BoolExprImpl>;
-  DISALLOW_COPY_AND_ASSIGN(BoolExprImpl);
-};
-
-// Internal interface implemented by ResultExpr implementations.
-class SANDBOX_EXPORT ResultExprImpl : public base::RefCounted<ResultExprImpl> {
- public:
-  ResultExprImpl() {}
-  virtual ErrorCode Compile(SandboxBPF* sb) const = 0;
-  virtual bool HasUnsafeTraps() const;
-
- protected:
-  virtual ~ResultExprImpl() {}
-
- private:
-  friend class base::RefCounted<ResultExprImpl>;
-  DISALLOW_COPY_AND_ASSIGN(ResultExprImpl);
-};
-
 }  // namespace internal
 
 template <typename T>
 Arg<T>::Arg(int num)
     : num_(num), mask_(internal::DefaultMask(sizeof(T))) {
 }
 
 // Definition requires ArgEq to have been declared.  Moved out-of-line
 // to minimize how much internal clutter users have to ignore while
 // reading the header documentation.
@@ skipping 32 matching lines @@
 }
 
 template <typename T>
 ResultExpr Caser<T>::Default(ResultExpr result) const {
   return elser_.Else(result);
 }
 
 }  // namespace bpf_dsl
 }  // namespace sandbox
 
+extern template class SANDBOX_EXPORT
+    scoped_refptr<const sandbox::bpf_dsl::internal::BoolExprImpl>;
+extern template class SANDBOX_EXPORT
+    scoped_refptr<const sandbox::bpf_dsl::internal::ResultExprImpl>;
+
 #endif  // SANDBOX_LINUX_BPF_DSL_BPF_DSL_H_