Convert to fancy new visitors

6 files changed, 187 insertions, 354 deletions

diff --git a/paludis/resolver/allowed_to_remove_helper.cc b/paludis/resolver/allowed_to_remove_helper.cc
index b68eb8376..c628dfea9 100644
--- a/paludis/resolver/allowed_to_remove_helper.cc
+++ b/paludis/resolver/allowed_to_remove_helper.cc
@@ -1,7 +1,7 @@
 /* vim: set sw=4 sts=4 et foldmethod=syntax : */
 
 /*
- * Copyright (c) 2010, 2011 Ciaran McCreesh
+ * Copyright (c) 2010, 2011, 2013 Ciaran McCreesh
  *
  * This file is part of the Paludis package manager. Paludis is free software;
  * you can redistribute it and/or modify it under the terms of the GNU General
@@ -58,60 +58,29 @@ AllowedToRemoveHelper::add_allowed_to_remove_spec(const PackageDepSpec & spec)
     _imp->allowed_to_remove_specs.insert(spec);
 }
 
-namespace
-{
-    struct AllowedToRemoveVisitor
-    {
-        bool visit(const DependentReason &) const
-        {
-            return true;
-        }
-
-        bool visit(const TargetReason &) const
-        {
-            return true;
-        }
-
-        bool visit(const DependencyReason &) const
-        {
-            return false;
-        }
-
-        bool visit(const WasUsedByReason &) const
-        {
-            return true;
-        }
-
-        bool visit(const ViaBinaryReason &) const
-        {
-            return false;
-        }
-
-        bool visit(const SetReason & r) const
-        {
-            return r.reason_for_set()->accept_returning<bool>(*this);
-        }
-
-        bool visit(const LikeOtherDestinationTypeReason & r) const
-        {
-            return r.reason_for_other()->accept_returning<bool>(*this);
-        }
-
-        bool visit(const PresetReason &) const
-        {
-            return false;
-        }
-    };
-}
-
 bool
 AllowedToRemoveHelper::operator() (
         const std::shared_ptr<const Resolution> & resolution,
         const std::shared_ptr<const PackageID> & id) const
 {
+    auto v = make_visitor(
+            [&] (const DependentReason &)  { return true; },
+            [&] (const TargetReason &)     { return true; },
+            [&] (const DependencyReason &) { return false; },
+            [&] (const WasUsedByReason &)  { return true; },
+            [&] (const ViaBinaryReason &)  { return false; },
+            [&] (const PresetReason &)     { return false; },
+            [&] (const SetReason & r, const Revisit<bool, Reason> & revisit) {
+                return revisit(*r.reason_for_set());
+            },
+            [&] (const LikeOtherDestinationTypeReason & r, const Revisit<bool, Reason> & revisit) {
+                return revisit(*r.reason_for_other());
+            }
+            );
+
     for (auto c(resolution->constraints()->begin()), c_end(resolution->constraints()->end()) ;
             c != c_end ; ++c)
-        if ((*c)->reason()->accept_returning<bool>(AllowedToRemoveVisitor()))
+        if ((*c)->reason()->accept_returning<bool>(v))
             return true;
 
     return _imp->allowed_to_remove_specs.match_any(_imp->env, id, { });
@@ -121,3 +90,4 @@ namespace paludis
 {
     template class Pimp<AllowedToRemoveHelper>;
 }
+
diff --git a/paludis/resolver/confirm_helper.cc b/paludis/resolver/confirm_helper.cc
index c845f88cc..3908cff96 100644
--- a/paludis/resolver/confirm_helper.cc
+++ b/paludis/resolver/confirm_helper.cc
@@ -1,7 +1,7 @@
 /* vim: set sw=4 sts=4 et foldmethod=syntax : */
 
 /*
- * Copyright (c) 2010, 2011 Ciaran McCreesh
+ * Copyright (c) 2010, 2011, 2013 Ciaran McCreesh
  *
  * This file is part of the Paludis package manager. Paludis is free software;
  * you can redistribute it and/or modify it under the terms of the GNU General
@@ -86,72 +86,53 @@ ConfirmHelper::set_allowed_to_break_system(const bool b)
     _imp->allowed_to_break_system = b;
 }
 
-namespace
-{
-    struct ConfirmVisitor
-    {
-        const Environment * const env;
-        const PackageDepSpecCollection & permit_downgrade_specs;
-        const PackageDepSpecCollection & permit_old_version_specs;
-        const PackageDepSpecCollection & allowed_to_break_specs;
-        const bool allowed_to_break_system;
-        const std::shared_ptr<const PackageID> id;
-
-        bool visit(const DowngradeConfirmation &) const
-        {
-            if (id)
-                if (permit_downgrade_specs.match_any(env, id, { }))
-                    return true;
-
-            return false;
-        }
-
-        bool visit(const NotBestConfirmation &) const
-        {
-            if (id)
-                if (permit_old_version_specs.match_any(env, id, { }))
-                    return true;
-
-            return false;
-        }
-
-        bool visit(const BreakConfirmation &) const
-        {
-            if (id)
-                if (allowed_to_break_specs.match_any(env, id, { }))
-                    return true;
-
-            return false;
-        }
-
-        bool visit(const RemoveSystemPackageConfirmation &) const
-        {
-            return allowed_to_break_system;
-        }
-
-        bool visit(const MaskedConfirmation &) const
-        {
-            return false;
-        }
-
-        bool visit(const ChangedChoicesConfirmation &) const
-        {
-            return false;
-        }
-    };
-}
-
 bool
 ConfirmHelper::operator() (
         const std::shared_ptr<const Resolution> & resolution,
         const std::shared_ptr<const RequiredConfirmation> & confirmation) const
 {
     auto id(get_decided_id_or_null(resolution->decision()));
-    return confirmation->accept_returning<bool>(ConfirmVisitor{_imp->env, _imp->permit_downgrade_specs,
-            _imp->permit_old_version_specs, _imp->allowed_to_break_specs, _imp->allowed_to_break_system, id});
+    return confirmation->make_accept_returning(
+            [&] (const DowngradeConfirmation &) {
+                if (id)
+                    if (_imp->permit_downgrade_specs.match_any(_imp->env, id, { }))
+                        return true;
+
+                return false;
+            },
+
+            [&] (const NotBestConfirmation &) {
+                if (id)
+                    if (_imp->permit_old_version_specs.match_any(_imp->env, id, { }))
+                        return true;
+
+                return false;
+            },
+
+            [&] (const BreakConfirmation &) {
+                if (id)
+                    if (_imp->allowed_to_break_specs.match_any(_imp->env, id, { }))
+                        return true;
+
+                return false;
+            },
+
+            [&] (const RemoveSystemPackageConfirmation &) {
+                return _imp->allowed_to_break_system;
+            },
+
+            [&] (const MaskedConfirmation &) {
+                return false;
+            },
+
+            [&] (const ChangedChoicesConfirmation &) {
+                return false;
+            }
+        );
 }
 
 namespace paludis
 {
     template class Pimp<ConfirmHelper>;
 }
+
diff --git a/paludis/resolver/decision_utils.cc b/paludis/resolver/decision_utils.cc
index 04591e5b4..57275d6b2 100644
--- a/paludis/resolver/decision_utils.cc
+++ b/paludis/resolver/decision_utils.cc
@@ -1,7 +1,7 @@
 /* vim: set sw=4 sts=4 et foldmethod=syntax : */
 
 /*
- * Copyright (c) 2010 Ciaran McCreesh
+ * Copyright (c) 2010, 2013 Ciaran McCreesh
  *
  * This file is part of the Paludis package manager. Paludis is free software;
  * you can redistribute it and/or modify it under the terms of the GNU General
@@ -23,45 +23,16 @@
 using namespace paludis;
 using namespace paludis::resolver;
 
-namespace
-{
-    struct IDVisitor
-    {
-        std::shared_ptr<const PackageID> visit(const ChangesToMakeDecision & decision) const
-        {
-            return decision.origin_id();
-        }
-
-        std::shared_ptr<const PackageID> visit(const BreakDecision & decision) const
-        {
-            return decision.existing_id();
-        }
-
-        std::shared_ptr<const PackageID> visit(const ExistingNoChangeDecision & decision) const
-        {
-            return decision.existing_id();
-        }
-
-        std::shared_ptr<const PackageID> visit(const NothingNoChangeDecision &) const
-        {
-            return nullptr;
-        }
-
-        std::shared_ptr<const PackageID> visit(const RemoveDecision &) const
-        {
-            return nullptr;
-        }
-
-        std::shared_ptr<const PackageID> visit(const UnableToMakeDecision &) const
-        {
-            return nullptr;
-        }
-    };
-}
-
 const std::shared_ptr<const PackageID>
-paludis::resolver::get_decided_id_or_null(const std::shared_ptr<const Decision> & decision)
+paludis::resolver::get_decided_id_or_null(const std::shared_ptr<const Decision> & d)
 {
-    return decision->accept_returning<std::shared_ptr<const PackageID> >(IDVisitor());
+    return d->make_accept_returning(
+            [&] (const ChangesToMakeDecision & decision)    { return decision.origin_id(); },
+            [&] (const BreakDecision & decision)            { return decision.existing_id(); },
+            [&] (const ExistingNoChangeDecision & decision) { return decision.existing_id(); },
+            [&] (const NothingNoChangeDecision &)           { return nullptr; },
+            [&] (const RemoveDecision &)                    { return nullptr; },
+            [&] (const UnableToMakeDecision &)              { return nullptr; }
+        );
 }
 
diff --git a/paludis/resolver/get_destination_types_for_blocker_helper.cc b/paludis/resolver/get_destination_types_for_blocker_helper.cc
index efa9c89d1..3374f6059 100644
--- a/paludis/resolver/get_destination_types_for_blocker_helper.cc
+++ b/paludis/resolver/get_destination_types_for_blocker_helper.cc
@@ -1,7 +1,7 @@
 /* vim: set sw=4 sts=4 et foldmethod=syntax : */
 
 /*
- * Copyright (c) 2010, 2011 Ciaran McCreesh
+ * Copyright (c) 2010, 2011, 2013 Ciaran McCreesh
  *
  * This file is part of the Paludis package manager. Paludis is free software;
  * you can redistribute it and/or modify it under the terms of the GNU General
@@ -24,7 +24,6 @@
 #include <paludis/resolver/resolution.hh>
 #include <paludis/resolver/decision.hh>
 #include <paludis/util/pimp-impl.hh>
-#include <paludis/util/visitor_cast.hh>
 #include <paludis/util/make_shared_copy.hh>
 #include <paludis/util/make_named_values.hh>
 #include <paludis/util/stringify.hh>
@@ -67,63 +66,48 @@ GetDestinationTypesForBlockerHelper::set_target_destination_type(const Destinati
     _imp->target_destination_type = d;
 }
 
-namespace
-{
-    struct DestinationTypesFinder
-    {
-        const DestinationType target_destination_type;
-
-        DestinationTypes visit(const TargetReason &) const
-        {
-            return { target_destination_type };
-        }
-
-        DestinationTypes visit(const DependentReason &) const
-        {
-            return { dt_install_to_slash };
-        }
-
-        DestinationTypes visit(const ViaBinaryReason &) const
-        {
-            return { };
-        }
-
-        DestinationTypes visit(const WasUsedByReason &) const
-        {
-            return { dt_install_to_slash };
-        }
-
-        DestinationTypes visit(const DependencyReason &) const
-        {
-            return { dt_install_to_slash };
-        }
-
-        DestinationTypes visit(const PresetReason &) const
-        {
-            return { };
-        }
-
-        DestinationTypes visit(const LikeOtherDestinationTypeReason & r) const
-        {
-            return r.reason_for_other()->accept_returning<DestinationTypes>(*this);
-        }
-
-        DestinationTypes visit(const SetReason & r) const
-        {
-            return r.reason_for_set()->accept_returning<DestinationTypes>(*this);
-        }
-    };
-}
-
 DestinationTypes
 GetDestinationTypesForBlockerHelper::operator() (
         const BlockDepSpec &,
         const std::shared_ptr<const Reason> & reason) const
 {
-    return reason->accept_returning<DestinationTypes>(DestinationTypesFinder{_imp->target_destination_type});
+    return reason->make_accept_returning(
+            [&] (const TargetReason &) {
+                return DestinationTypes{ _imp->target_destination_type };
+            },
+
+            [&] (const DependentReason &) {
+                return DestinationTypes{ dt_install_to_slash };
+            },
+
+            [&] (const ViaBinaryReason &) {
+                return DestinationTypes{ };
+            },
+
+            [&] (const WasUsedByReason &) {
+                return DestinationTypes{ dt_install_to_slash };
+            },
+
+            [&] (const DependencyReason &) {
+                return DestinationTypes{ dt_install_to_slash };
+            },
+
+            [&] (const PresetReason &) {
+                return DestinationTypes{ };
+            },
+
+            [&] (const LikeOtherDestinationTypeReason & r, const Revisit<DestinationTypes, Reason> & revisit) {
+                return revisit(*r.reason_for_other());
+            },
+
+            [&] (const SetReason & r, const Revisit<DestinationTypes, Reason> & revisit) {
+                return revisit(*r.reason_for_set());
+            }
+            );
 }
 
 namespace paludis
 {
     template class Pimp<GetDestinationTypesForBlockerHelper>;
 }
+
diff --git a/paludis/resolver/get_destination_types_for_error_helper.cc b/paludis/resolver/get_destination_types_for_error_helper.cc
index d63d276fb..bdac67d27 100644
--- a/paludis/resolver/get_destination_types_for_error_helper.cc
+++ b/paludis/resolver/get_destination_types_for_error_helper.cc
@@ -66,60 +66,25 @@ GetDestinationTypesForErrorHelper::set_target_destination_type(const Destination
     _imp->target_destination_type = d;
 }
 
-namespace
-{
-    struct DestinationTypesFinder
-    {
-        const DestinationType target_destination_type;
-
-        DestinationTypes visit(const TargetReason &) const
-        {
-            return { target_destination_type };
-        }
-
-        DestinationTypes visit(const DependentReason &) const
-        {
-            return { dt_install_to_slash };
-        }
-
-        DestinationTypes visit(const ViaBinaryReason &) const
-        {
-            return { };
-        }
-
-        DestinationTypes visit(const WasUsedByReason &) const
-        {
-            return { dt_install_to_slash };
-        }
-
-        DestinationTypes visit(const DependencyReason &) const
-        {
-            return { dt_install_to_slash };
-        }
-
-        DestinationTypes visit(const PresetReason &) const
-        {
-            return { };
-        }
-
-        DestinationTypes visit(const LikeOtherDestinationTypeReason & r) const
-        {
-            return r.reason_for_other()->accept_returning<DestinationTypes>(*this);
-        }
-
-        DestinationTypes visit(const SetReason & r) const
-        {
-            return r.reason_for_set()->accept_returning<DestinationTypes>(*this);
-        }
-    };
-}
-
 DestinationTypes
 GetDestinationTypesForErrorHelper::operator() (
         const PackageDepSpec &,
         const std::shared_ptr<const Reason> & reason) const
 {
-    return reason->accept_returning<DestinationTypes>(DestinationTypesFinder{_imp->target_destination_type});
+    return reason->make_accept_returning(
+            [&] (const TargetReason &)     { return DestinationTypes{ _imp->target_destination_type }; },
+            [&] (const DependentReason &)  { return DestinationTypes{ dt_install_to_slash }; },
+            [&] (const ViaBinaryReason &)  { return DestinationTypes{ }; },
+            [&] (const WasUsedByReason &)  { return DestinationTypes{ dt_install_to_slash }; },
+            [&] (const DependencyReason &) { return DestinationTypes{ dt_install_to_slash }; },
+            [&] (const PresetReason &)     { return DestinationTypes{ }; },
+            [&] (const LikeOtherDestinationTypeReason & r, const Revisit<DestinationTypes, Reason> & revisit) {
+                return revisit(*r.reason_for_other());
+            },
+            [&] (const SetReason & r, const Revisit<DestinationTypes, Reason> & revisit) {
+                return revisit(*r.reason_for_set());
+            }
+        );
 }
 
 namespace paludis
diff --git a/paludis/resolver/get_resolvents_for_helper.cc b/paludis/resolver/get_resolvents_for_helper.cc
index 3f255246b..f9e431972 100644
--- a/paludis/resolver/get_resolvents_for_helper.cc
+++ b/paludis/resolver/get_resolvents_for_helper.cc
@@ -160,112 +160,6 @@ GetResolventsForHelper::set_target_slots(const bool best, const bool installed,
 
 namespace
 {
-    struct DestinationTypesFinder
-    {
-        const Environment * const env;
-        const DestinationType target_destination_type;
-        const bool want_target_dependencies;
-        const bool want_target_runtime_dependencies;
-        const bool want_dependencies_on_slash;
-        const bool want_runtime_dependencies_on_slash;
-        const std::shared_ptr<const PackageID> package_id;
-
-        DestinationTypes visit(const TargetReason &) const
-        {
-            return { target_destination_type };
-        }
-
-        DestinationTypes visit(const DependentReason &) const
-        {
-            return { dt_install_to_slash };
-        }
-
-        DestinationTypes visit(const ViaBinaryReason &) const
-        {
-            return { };
-        }
-
-        DestinationTypes visit(const WasUsedByReason &) const
-        {
-            return { dt_install_to_slash };
-        }
-
-        DestinationTypes visit(const DependencyReason & dep) const
-        {
-            DestinationTypes extras, slash;
-
-            switch (target_destination_type)
-            {
-                case dt_create_binary:
-                    {
-                        bool binary_if_possible(false);
-                        if (want_target_dependencies)
-                            binary_if_possible = true;
-                        else if (want_target_runtime_dependencies)
-                        {
-                            /* this will track run deps of build deps, which isn't
-                             * really right... */
-                            if (is_run_or_post_dep(env, package_id, dep.sanitised_dependency()))
-                                binary_if_possible = true;
-                        }
-
-                        if (binary_if_possible && can_make_binary_for(package_id))
-                            extras += dt_create_binary;
-                    }
-                    break;
-
-                case dt_install_to_chroot:
-                    {
-                        bool chroot_if_possible(false);
-                        if (want_target_dependencies)
-                            chroot_if_possible = true;
-                        else if (want_target_runtime_dependencies)
-                        {
-                            if (is_run_or_post_dep(env, package_id, dep.sanitised_dependency()))
-                                chroot_if_possible = true;
-                        }
-
-                        if (chroot_if_possible && can_chroot(package_id))
-                            extras += dt_install_to_chroot;
-                    }
-                    break;
-
-                case dt_install_to_slash:
-                    break;
-
-                case last_dt:
-                    throw InternalError(PALUDIS_HERE, "unhandled dt");
-            }
-
-            if (want_runtime_dependencies_on_slash ^ want_dependencies_on_slash)
-            {
-                if (want_dependencies_on_slash && ! is_run_or_post_dep(env, package_id, dep.sanitised_dependency()))
-                    slash += dt_install_to_slash;
-                if (want_runtime_dependencies_on_slash && is_run_or_post_dep(env, package_id, dep.sanitised_dependency()))
-                    slash += dt_install_to_slash;
-            }
-            else if (want_runtime_dependencies_on_slash || want_dependencies_on_slash)
-                slash += dt_install_to_slash;
-
-            return extras | slash;
-        }
-
-        DestinationTypes visit(const PresetReason &) const
-        {
-            return { };
-        }
-
-        DestinationTypes visit(const LikeOtherDestinationTypeReason & r) const
-        {
-            return r.reason_for_other()->accept_returning<DestinationTypes>(*this);
-        }
-
-        DestinationTypes visit(const SetReason & r) const
-        {
-            return r.reason_for_set()->accept_returning<DestinationTypes>(*this);
-        }
-    };
-
     DestinationTypes get_destination_types_for_fn(
             const Environment * const env,
             const PackageDepSpec &,
@@ -277,9 +171,77 @@ namespace
             const std::shared_ptr<const PackageID> & package_id,
             const std::shared_ptr<const Reason> & reason)
     {
-        DestinationTypesFinder f{env, target_destination_type, want_target_dependencies, want_target_runtime_dependencies,
-            want_dependencies_on_slash, want_runtime_dependencies_on_slash, package_id};
-        return reason->accept_returning<DestinationTypes>(f);
+        return reason->make_accept_returning(
+                [&] (const TargetReason &)    { return DestinationTypes{ target_destination_type }; },
+                [&] (const DependentReason &) { return DestinationTypes{ dt_install_to_slash }; },
+                [&] (const ViaBinaryReason &) { return DestinationTypes{ }; },
+                [&] (const WasUsedByReason &) { return DestinationTypes{ dt_install_to_slash }; },
+                [&] (const PresetReason &)    { return DestinationTypes{ }; },
+                [&] (const LikeOtherDestinationTypeReason & r, const Revisit<DestinationTypes, Reason> & revisit) {
+                    return revisit(*r.reason_for_other());
+                },
+                [&] (const SetReason & r, const Revisit<DestinationTypes, Reason> & revisit) {
+                    return revisit(*r.reason_for_set());
+                },
+                [&] (const DependencyReason & dep) {
+                    DestinationTypes extras, slash;
+
+                    switch (target_destination_type)
+                    {
+                        case dt_create_binary:
+                            {
+                                bool binary_if_possible(false);
+                                if (want_target_dependencies)
+                                    binary_if_possible = true;
+                                else if (want_target_runtime_dependencies)
+                                {
+                                    /* this will track run deps of build deps, which isn't
+                                     * really right... */
+                                    if (is_run_or_post_dep(env, package_id, dep.sanitised_dependency()))
+                                        binary_if_possible = true;
+                                }
+
+                                if (binary_if_possible && can_make_binary_for(package_id))
+                                    extras += dt_create_binary;
+                            }
+                            break;
+
+                        case dt_install_to_chroot:
+                            {
+                                bool chroot_if_possible(false);
+                                if (want_target_dependencies)
+                                    chroot_if_possible = true;
+                                else if (want_target_runtime_dependencies)
+                                {
+                                    if (is_run_or_post_dep(env, package_id, dep.sanitised_dependency()))
+                                        chroot_if_possible = true;
+                                }
+
+                                if (chroot_if_possible && can_chroot(package_id))
+                                    extras += dt_install_to_chroot;
+                            }
+                            break;
+
+                        case dt_install_to_slash:
+                            break;
+
+                        case last_dt:
+                            throw InternalError(PALUDIS_HERE, "unhandled dt");
+                    }
+
+                    if (want_runtime_dependencies_on_slash ^ want_dependencies_on_slash)
+                    {
+                        if (want_dependencies_on_slash && ! is_run_or_post_dep(env, package_id, dep.sanitised_dependency()))
+                            slash += dt_install_to_slash;
+                        if (want_runtime_dependencies_on_slash && is_run_or_post_dep(env, package_id, dep.sanitised_dependency()))
+                            slash += dt_install_to_slash;
+                    }
+                    else if (want_runtime_dependencies_on_slash || want_dependencies_on_slash)
+                        slash += dt_install_to_slash;
+
+                    return extras | slash;
+                }
+            );
     }
 
     bool can_use_cache(const PackageDepSpec & spec)