Catch C++ xapian exceptions and raise them as scheme exceptions.

Uncaught C++ exceptions crash the guile process without providing
scheme code any opportunity to respond.

* except.i, xapian/error.scm: New files.
* xapian.i.in: Include except.i.
* Makefile.am (SOURCES): Add xapian/error.scm.
(xapian_wrap.cc xapian/wrap.scm &): Depend on except.i.

1 files changed, 50 insertions, 0 deletions

diff --git a/except.i b/except.i
new file mode 100644
index 0000000..fce1471
--- /dev/null
+++ b/except.i
@@ -0,0 +1,50 @@
+/* guile-xapian --- Guile bindings for Xapian
+ * Copyright © 2023 Arun Isaac <arunisaac@systemreboot.net>
+ *
+ * This file is part of guile-xapian.
+ *
+ * guile-xapian is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * guile-xapian is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with guile-xapian.  If not, see
+ * <https://www.gnu.org/licenses/>.
+ */
+
+%{
+void handle_exception() {
+  string msg;
+  try {
+    throw;
+  } catch (const Xapian::Error &e) {
+    // TODO: Handle each Xapian error class separately and raise
+    // different scheme conditions for each.
+    msg = e.get_description();
+  } catch (const std::exception &e) {
+    msg = "std::exception: ";
+    msg += e.what();
+  } catch (...) {
+    msg = "unknown error in Xapian";
+  }
+  scm_call_1(scm_c_public_ref("xapian error", "raise-xapian-exception"),
+             scm_from_stringn(msg.c_str(),
+                              msg.length(),
+                              "us-ascii",
+                              SCM_FAILED_CONVERSION_ESCAPE_SEQUENCE));
+}
+%}
+
+%exception {
+    try {
+	$function
+    } catch (...) {
+      handle_exception();
+    }
+}