From 5ce035b92001119f0ef259ae0b182bddfd064e46 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Tue, 9 Jul 2024 16:29:16 +0300
Subject: [PATCH] Add a prepare() hook to Loader

Also add an overload of finish() which is called even when an exception
occurs and receives a bool parameter to indicate if loading was
successful.
---
 source/loader.cpp | 31 ++++++++++++++++++++++---------
 source/loader.h   | 11 +++++++++++
 2 files changed, 33 insertions(+), 9 deletions(-)

diff --git a/source/loader.cpp b/source/loader.cpp
index b09fa87..5b39569 100644
--- a/source/loader.cpp
+++ b/source/loader.cpp
@@ -1,3 +1,4 @@
+#include <exception>
 #include <msp/core/algorithm.h>
 #include <msp/core/raii.h>
 #include <msp/fs/utils.h>
@@ -56,6 +57,7 @@ void Loader::load(Parser &p)
 
 	context = FS::basename(p.get_source());
 
+	Activator activate(*this);
 	while(p)
 	{
 		if(p.peek(0))
@@ -68,9 +70,6 @@ void Loader::load(Parser &p)
 				load_statement(st);
 		}
 	}
-	finish();
-	for(Loader *l: aux_loaders)
-		l->finish();
 }
 
 void Loader::load(const Statement &st)
@@ -78,11 +77,9 @@ void Loader::load(const Statement &st)
 	if(!actions)
 		throw logic_error("no actions");
 
+	Activator activate(*this);
 	for(const Statement &s: st.sub)
 		load_statement(s);
-	finish();
-	for(Loader *l: aux_loaders)
-		l->finish();
 }
 
 void Loader::load_direct(Parser &p, unsigned l)
@@ -146,10 +143,8 @@ void Loader::load_sub_with(Loader &ldr)
 {
 	if(direct)
 	{
+		Activator activate(ldr);
 		ldr.load_direct(*cur_parser, cur_level+1);
-		ldr.finish();
-		for(Loader *l: ldr.aux_loaders)
-			l->finish();
 	}
 	else if(cur_st)
 	{
@@ -258,5 +253,23 @@ const string &Loader::get_keyword() const
 	return cur_st->keyword;
 }
 
+
+Loader::Activator::Activator(Loader &l):
+	ldr(l),
+	exc_count(uncaught_exceptions())
+{
+	ldr.prepare();
+	for(Loader *a: ldr.aux_loaders)
+		a->prepare();
+}
+
+Loader::Activator::~Activator()
+{
+	bool success = (uncaught_exceptions()==exc_count);
+	ldr.finish(success);
+	for(Loader *a: ldr.aux_loaders)
+		a->finish(success);
+}
+
 } // namespace DataFile
 } // namespace Msp
diff --git a/source/loader.h b/source/loader.h
index abad2f1..c759f59 100644
--- a/source/loader.h
+++ b/source/loader.h
@@ -76,6 +76,15 @@ protected:
 	};
 
 private:
+	struct Activator
+	{
+		Loader &ldr;
+		int exc_count = 0;
+
+		Activator(Loader &);
+		~Activator();
+	};
+
 	ActionMap local_actions;
 	ActionMap *actions = nullptr;
 	std::string context;
@@ -202,7 +211,9 @@ protected:
 	implement dynamic keywords. */
 	const std::string &get_keyword() const;
 
+	virtual void prepare() { }
 	virtual void finish() { }
+	virtual void finish(bool s) { if(s) finish(); }
 };
 
 
-- 
2.45.2