From 77da1ae28c6e0dfbbd1c5b989d1c5c6f95b0728a Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Wed, 6 Sep 2023 15:05:42 +0300
Subject: [PATCH] Refactor handling of actions in Loader

Auxiliary loaders now work with the binary format and the flow control
structures are more clear in general.
---
 source/loader.cpp     | 45 ++++++++++++++++++++++++++++---------------
 source/loader.h       |  4 +++-
 source/loaderaction.h |  9 +++++++++
 3 files changed, 41 insertions(+), 17 deletions(-)

diff --git a/source/loader.cpp b/source/loader.cpp
index 7e910b8..8f443c3 100644
--- a/source/loader.cpp
+++ b/source/loader.cpp
@@ -1,3 +1,4 @@
+#include <msp/core/algorithm.h>
 #include <msp/core/raii.h>
 #include <msp/strings/format.h>
 #include "except.h"
@@ -92,15 +93,16 @@ void Loader::load_direct(Parser &p, unsigned l)
 		if(!key)
 			break;
 
-		LoaderAction *act = find_action(*key);
-		if(act)
+		if(LoaderAction *act = find_action(*key))
 		{
 			SetFlag set_direct(direct);
 			if(!p.parse_and_load(l, *this, *act))
 				throw logic_error("direct load failed");
 		}
+		else if(Loader *ldr = find_auxiliary_loader(*key))
+			ldr->load_direct(p, l);
 		else
-			load_statement(p.parse());
+			unrecognized(*key);
 	}
 }
 
@@ -112,21 +114,17 @@ void Loader::load_statement(const Statement &st)
 	{
 		StatementKey key(st.keyword, st.get_signature());
 
-		if(!aux_loaders.empty() && !has_action(key))
-		{
-			for(Loader *l: aux_loaders)
-				if(l->has_action(key))
-					return l->load_statement(st);
-		}
-
-		LoaderAction *act = find_action(key);
-		if(act)
+		if(LoaderAction *act = find_action(key))
 		{
 			sub_loaded = false;
 			act->execute(*this, st);
 			if(check_sub_loads && !st.sub.empty() && !sub_loaded)
 				throw logic_error("substatements ignored");
 		}
+		else if(Loader *ldr = find_auxiliary_loader(key))
+			ldr->load_statement(st);
+		else
+			unrecognized(key);
 	}
 	catch(const data_error &e)
 	{
@@ -174,7 +172,7 @@ void Loader::add(const string &kwd, LoaderAction *act)
 	if(!actions)
 		actions = &local_actions;
 
-	StatementKey key(kwd, (act ? act->get_signature() : "*"));
+	StatementKey key(kwd, act->get_signature());
 	ActionMap::iterator i = actions->find(key);
 	if(i!=actions->end())
 	{
@@ -211,7 +209,7 @@ LoaderAction *Loader::find_action(const StatementKey &key) const
 	auto end = actions->upper_bound(StatementKey(key.keyword, "~"));
 
 	if(begin==end)
-		throw unknown_keyword(key.keyword);
+		return nullptr;
 
 	LoaderAction *act = nullptr;
 	int match = 0;
@@ -225,10 +223,25 @@ LoaderAction *Loader::find_action(const StatementKey &key) const
 		}
 	}
 
-	if(!match)
+	return act;
+}
+
+Loader *Loader::find_auxiliary_loader(const StatementKey &key) const
+{
+	auto i = find_if(aux_loaders, [&key](Loader *l){ return l->has_action(key); });
+	return (i!=aux_loaders.end() ? *i : nullptr);
+}
+
+void Loader::unrecognized(const StatementKey &key) const
+{
+	if(!actions)
+		throw logic_error("no actions");
+
+	auto i = actions->lower_bound(StatementKey(key.keyword, string()));
+	if(i!=actions->end() && i->first.keyword==key.keyword)
 		throw invalid_signature(key.keyword, key.signature);
 
-	return act;
+	throw unknown_keyword(key.keyword);
 }
 
 const string &Loader::get_source() const
diff --git a/source/loader.h b/source/loader.h
index 5b96cb0..59ebc23 100644
--- a/source/loader.h
+++ b/source/loader.h
@@ -135,7 +135,7 @@ protected:
 
 	/** Adds a keyword that is recognized but ignored. */
 	void add(const std::string &k)
-	{ add(k, nullptr); }
+	{ add(k, new LoaderDiscard); }
 
 private:
 	void add(const std::string &, LoaderAction *);
@@ -146,6 +146,8 @@ protected:
 private:
 	bool has_action(const StatementKey &) const;
 	LoaderAction *find_action(const StatementKey &) const;
+	Loader *find_auxiliary_loader(const StatementKey &) const;
+	void unrecognized(const StatementKey &) const;
 
 protected:
 	/** Returns the source of the statement being processed.  This can be used
diff --git a/source/loaderaction.h b/source/loaderaction.h
index 9e08dac..0c56eab 100644
--- a/source/loaderaction.h
+++ b/source/loaderaction.h
@@ -37,6 +37,15 @@ public:
 };
 
 
+class LoaderDiscard: public LoaderAction
+{
+public:
+	void execute(Loader &, const Statement &) const override { }
+	void execute(Loader &, const ArgumentStore &) const override { }
+	std::string get_signature() const override { return "*"; };
+};
+
+
 /**
 Loads a statement by calling a function that takes no arguments.
 */
-- 
2.45.2