Cleanup: remove use of an exception in favour of an optional.

4 files changed, 11 insertions, 20 deletions

diff --git a/src/exceptions.cc b/src/exceptions.cc
index fce1b583..ebcd70da 100644
--- a/src/exceptions.cc
+++ b/src/exceptions.cc
@@ -179,13 +179,6 @@ MainSoundConfigurationError::MainSoundConfigurationError (std::string s)
 }
 
 
-UnknownChannelIdError::UnknownChannelIdError (std::string id)
-	: runtime_error(String::compose("Unrecognised channel ID '%1'", id))
-{
-
-}
-
-
 NoReelsError::NoReelsError ()
 	: runtime_error("Cannot write a CPL which has no reels")
 {
diff --git a/src/exceptions.h b/src/exceptions.h
index 49f5a21e..5ccd616c 100644
--- a/src/exceptions.h
+++ b/src/exceptions.h
@@ -330,13 +330,6 @@ public:
 };
 
 
-class UnknownChannelIdError : public std::runtime_error
-{
-public:
-	UnknownChannelIdError (std::string s);
-};
-
-
 class NoReelsError : public std::runtime_error
 {
 public:
diff --git a/src/main_sound_configuration.cc b/src/main_sound_configuration.cc
index c22da40b..f9bb07c1 100644
--- a/src/main_sound_configuration.cc
+++ b/src/main_sound_configuration.cc
@@ -83,9 +83,9 @@ MainSoundConfiguration::MainSoundConfiguration(string s)
 		if (i == "-") {
 			_channels.push_back(optional<Channel>());
 		} else {
-			try {
-				_channels.push_back(mca_id_to_channel(i));
-			} catch (UnknownChannelIdError&) {
+			if (auto channel = mca_id_to_channel(i)) {
+				_channels.push_back(*channel);
+			} else {
 				_valid = false;
 			}
 		}
@@ -155,7 +155,7 @@ MainSoundConfiguration::set_mapping(int index, Channel c)
 }
 
 
-Channel
+optional<Channel>
 dcp::mca_id_to_channel(string id)
 {
 	transform(id.begin(), id.end(), id.begin(), ::tolower);
@@ -192,7 +192,7 @@ dcp::mca_id_to_channel(string id)
 		return Channel::SIGN_LANGUAGE;
 	}
 
-	throw UnknownChannelIdError(id);
+	return {};
 }
 
 
diff --git a/src/main_sound_configuration.h b/src/main_sound_configuration.h
index 2c872ba2..8c4ac596 100644
--- a/src/main_sound_configuration.h
+++ b/src/main_sound_configuration.h
@@ -53,7 +53,12 @@ enum class MCASoundField
 
 
 extern std::string channel_to_mca_id(Channel c, MCASoundField field);
-extern Channel mca_id_to_channel(std::string);
+
+/** @param id MCA channel ID
+ *  @return Corresponding dcp::Channel, or empty if the id is not recognised.
+ */
+extern boost::optional<Channel> mca_id_to_channel(std::string id);
+
 extern std::string channel_to_mca_name(Channel c, MCASoundField field);
 extern ASDCP::UL channel_to_mca_universal_label(Channel c, MCASoundField field, ASDCP::Dictionary const* dict);