Fix confusing error on trying to load a DoM project into the player (#1948).

2 files changed, 16 insertions, 4 deletions

diff --git a/src/lib/dcp_content.cc b/src/lib/dcp_content.cc
index 318e3ce52..256112eb2 100644
--- a/src/lib/dcp_content.cc
+++ b/src/lib/dcp_content.cc
@@ -186,10 +186,7 @@ DCPContent::read_directory (boost::filesystem::path p)
 		if (!have_metadata) {
 			throw DCPError ("No ASSETMAP or ASSETMAP.xml file found: is this a DCP?");
 		} else {
-			throw DCPError (
-				"This looks like a DCP-o-matic project folder, which cannot be added to a different project.  "
-				"Choose the DCP directory inside the DCP-o-matic project folder if that's what you want to import."
-				);
+			throw ProjectFolderError ();
 		}
 	}
 
diff --git a/src/lib/exceptions.h b/src/lib/exceptions.h
index 05cda9659..c64f561a8 100644
--- a/src/lib/exceptions.h
+++ b/src/lib/exceptions.h
@@ -266,6 +266,21 @@ public:
 	{}
 };
 
+
+/** @class ProjectFolderError
+ *  @brief An attempt has been made to read a DCP from a directory, but it looks
+ *  like the directory actually contains a DCP-o-matic project.
+ */
+class ProjectFolderError : public DCPError
+{
+public:
+	/* Code which catches this exception will provide their own message */
+	ProjectFolderError ()
+		: DCPError ("dummy")
+	{}
+};
+
+
 class InvalidSignerError : public std::runtime_error
 {
 public: