1 files changed, 196 insertions, 0 deletions
diff --git a/src/errors.c b/src/errors.c
new file mode 100644
index 0000000..b3e6aa3
--- /dev/null
+++ b/src/errors.c
@@ -0,0 +1,196 @@
+/***********************************************************
+Copyright 1991 by Stichting Mathematisch Centrum, Amsterdam, The
+Netherlands.
+
+ All Rights Reserved
+
+Permission to use, copy, modify, and distribute this software and its
+documentation for any purpose and without fee is hereby granted,
+provided that the above copyright notice appear in all copies and that
+both that copyright notice and this permission notice appear in
+supporting documentation, and that the names of Stichting Mathematisch
+Centrum or CWI not be used in advertising or publicity pertaining to
+distribution of the software without specific, written prior permission.
+
+STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO
+THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE
+FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
+OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+******************************************************************/
+
+/* Error handling -- see also run.c */
+
+/* New error handling interface.
+
+ The following problem exists (existed): methods of built-in modules
+ are called with 'self' and 'args' arguments, but without a context
+ argument, so they have no way to raise a specific exception.
+ The same is true for the object implementations: no context argument.
+ The old convention was to set 'errno' and to return NULL.
+ The caller (usually call_function() in eval.c) detects the NULL
+ return value and then calls puterrno(ctx) to turn the errno value
+ into a true exception. Problems with this approach are:
+ - it used standard errno values to indicate Python-specific errors,
+ but this means that when such an error code is reported by a system
+ call (e.g., in module posix), the user gets a confusing message
+ - errno is a global variable, which makes extensions to a multi-
+ threading environment difficult; e.g., in IRIX, multi-threaded
+ programs must use the function oserror() instead of looking in errno
+ - there is no portable way to add new error numbers for specic
+ situations -- the value space for errno is reserved to the OS, yet
+ the way to turn module-specific errors into a module-specific
+ exception requires module-specific values for errno
+ - there is no way to add a more situation-specific message to an
+ error.
+
+ The new interface solves all these problems. To return an error, a
+ built-in function calls err_set(exception), err_setval(exception,
+ value) or err_setstr(exception, string), and returns NULL. These
+ functions save the value for later use by puterrno(). To adapt this
+ scheme to a multi-threaded environment, only the implementation of
+ err_setval() has to be changed.
+*/
+
+#include "allobjects.h"
+
+#include <errno.h>
+#ifndef errno
+extern int errno;
+#endif
+
+#include "errcode.h"
+
+extern char *strerror PROTO((int));
+
+/* Last exception stored by err_setval() */
+
+static object *last_exception;
+static object *last_exc_val;
+
+void
+err_setval(exception, value)
+ object *exception;
+ object *value;
+{
+ XDECREF(last_exception);
+ XINCREF(exception);
+ last_exception = exception;
+
+ XDECREF(last_exc_val);
+ XINCREF(value);
+ last_exc_val = value;
+}
+
+void
+err_set(exception)
+ object *exception;
+{
+ err_setval(exception, (object *)NULL);
+}
+
+void
+err_setstr(exception, string)
+ object *exception;
+ char *string;
+{
+ object *value = newstringobject(string);
+ err_setval(exception, value);
+ XDECREF(value);
+}
+
+int
+err_occurred()
+{
+ return last_exception != NULL;
+}
+
+void
+err_get(p_exc, p_val)
+ object **p_exc;
+ object **p_val;
+{
+ *p_exc = last_exception;
+ last_exception = NULL;
+ *p_val = last_exc_val;
+ last_exc_val = NULL;
+}
+
+void
+err_clear()
+{
+ XDECREF(last_exception);
+ last_exception = NULL;
+ XDECREF(last_exc_val);
+ last_exc_val = NULL;
+}
+
+/* Convenience functions to set a type error exception and return 0 */
+
+int
+err_badarg()
+{
+ err_setstr(TypeError, "illegal argument type for built-in operation");
+ return 0;
+}
+
+object *
+err_nomem()
+{
+ err_set(MemoryError);
+ return NULL;
+}
+
+object *
+err_errno(exc)
+ object *exc;
+{
+ object *v = newtupleobject(2);
+ if (v != NULL) {
+ settupleitem(v, 0, newintobject((long)errno));
+ settupleitem(v, 1, newstringobject(strerror(errno)));
+ }
+ err_setval(exc, v);
+ XDECREF(v);
+ return NULL;
+}
+
+void
+err_badcall()
+{
+ err_setstr(SystemError, "bad argument to internal function");
+}
+
+/* Set the error appropriate to the given input error code (see errcode.h) */
+
+void
+err_input(err)
+ int err;
+{
+ switch (err) {
+ case E_DONE:
+ case E_OK:
+ break;
+ case E_SYNTAX:
+ err_setstr(RuntimeError, "syntax error");
+ break;
+ case E_TOKEN:
+ err_setstr(RuntimeError, "illegal token");
+ break;
+ case E_INTR:
+ err_set(KeyboardInterrupt);
+ break;
+ case E_NOMEM:
+ err_nomem();
+ break;
+ case E_EOF:
+ err_set(EOFError);
+ break;
+ default:
+ err_setstr(RuntimeError, "unknown input error");
+ break;
+ }
+}