New exception class QPDFSystemError (fixes #221)

1 files changed, 51 insertions, 0 deletions

diff --git a/libqpdf/QPDFSystemError.cc b/libqpdf/QPDFSystemError.cc
new file mode 100644
index 00000000..094341cd
--- /dev/null
+++ b/libqpdf/QPDFSystemError.cc
@@ -0,0 +1,51 @@
+#include <qpdf/QPDFSystemError.hh>
+#include <qpdf/QUtil.hh>
+#include <string.h>
+
+QPDFSystemError::QPDFSystemError(std::string const& description,
+                                 int system_errno) :
+    std::runtime_error(createWhat(description, system_errno)),
+    description(description),
+    system_errno(system_errno)
+{
+}
+
+QPDFSystemError::~QPDFSystemError() throw ()
+{
+}
+
+std::string
+QPDFSystemError::createWhat(std::string const& description,
+                            int system_errno)
+{
+    std::string message;
+#ifdef _MSC_VER
+    // "94" is mentioned in the MSVC docs, but it's still safe if the
+    // message is longer.  strerror_s is a templated function that
+    // knows the size of buf and truncates.
+    char buf[94];
+    if (strerror_s(buf, errno) != 0)
+    {
+        message = description + ": failed with an unknown error";
+    }
+    else
+    {
+        message = description + ": " + buf;
+    }
+#else
+    message = description + ": " + strerror(errno);
+#endif
+    return message;
+}
+
+std::string const&
+QPDFSystemError::getDescription() const
+{
+    return this->description;
+}
+
+int
+QPDFSystemError::getErrno() const
+{
+    return this->system_errno;
+}