Isolated emscripten in new lib

lib/emscripten/emtests/test_exceptions_convert.cpp

@@ -0,0 +1,137 @@
+// Copyright 2014 The Emscripten Authors.  All rights reserved.
+// Emscripten is available under two separate licenses, the MIT license and the
+// University of Illinois/NCSA Open Source License.  Both these licenses can be
+// found in the LICENSE file.
+
+#include <ios>
+#include <iostream>
+#include <sstream>
+#include <stdexcept>
+
+namespace
+{
+  struct TestEnum
+  {
+    enum type
+    {
+      Zero,
+      One
+    };
+  };
+
+  // An input operator a-la-boost date_time.  This input operator will catch
+  // anything and rethrow if the exception mask for the input stream is set to
+  // throw on failure.
+  std::istream& operator>>(std::istream& in, TestEnum::type& value)
+  {
+    try {
+      std::string raw;
+      if (not (in >> raw)) { return in; }
+      if (raw == "Zero")  { value = TestEnum::Zero; return in; }
+      if (raw == "One")   { value = TestEnum::One; return in; }
+
+      // The boost input operator uses it's own facet for input which can
+      // throw, so we simulate something failing by just throwing an exception
+      // directly.
+      throw std::exception();
+    }
+    catch (...) {
+      const std::ios_base::iostate exception_mask = in.exceptions();
+      if (std::ios_base::failbit & exception_mask) {
+        try { in.setstate(std::ios_base::failbit); }
+        catch(std::ios_base::failure&) {}
+        throw; // rethrow original exception
+      }
+      else {
+        in.setstate(std::ios_base::failbit);
+      }
+    }
+    return in;
+  }
+}
+
+int main()
+{
+  try {
+    // Show that the input operator works.
+    std::istringstream iss("One");
+    TestEnum::type value = TestEnum::Zero;
+
+    // We expect this to work.
+    iss >> value;
+    if (iss.fail()) {
+      std::cout
+        << "Failed to convert 'One' to TestEnum::type... fail"
+        << std::endl;
+    }
+    else {
+      std::cout
+        << "Successfully converted 'One' to TestEnum::type: " << value
+        << "... ok" << std::endl;
+    }
+  }
+  catch (...) {
+    std::cout
+      << "Unknown exception caught converting 'One' to TestEnum... fail"
+      << std::endl;
+  }
+
+  try {
+    // Show that invalid input set the fail bit on the input stream and no
+    // exception is thrown, since we did not enable them on the stream.
+    std::istringstream iss("Two");
+    TestEnum::type value = TestEnum::Zero;
+
+    // We expect this to fail.
+    iss >> value;
+    if (iss.fail()) {
+      std::cout
+        << "Failed to convert 'Two' to TestEnum::type... ok"
+        << std::endl;
+    }
+    else {
+      std::cout
+        << "Successfully converted 'Two' to TestEnum::type: " << value
+        << "... fail" << std::endl;
+    }
+  }
+  catch (...) {
+    std::cout
+      << "Unknown exception caught converting 'Two' to TestEnum... fail"
+      << std::endl;
+  }
+
+  try {
+    // Show that setting the input stream to throw on failure currently
+    // results in a JS exception being emitted.
+    std::istringstream iss("Three");
+    TestEnum::type value = TestEnum::Zero;
+
+    // Tell the stream to throw on failure.
+    iss.exceptions(std::ios_base::failbit);
+
+    // We expect this to fail.
+    iss >> value;
+    if (iss.fail()) {
+      std::cout
+        << "No exception thrown; Failed to convert 'Three' to TestEnum::type..."
+        "fail" << std::endl;
+    }
+    else {
+      std::cout
+        << "Successfully converted 'Three' to TestEnum::type: " << value
+        << "... fail" << std::endl;
+    }
+  }
+  catch(const std::ios_base::failure& ex) {
+    std::cout << "Caught exception: " << ex.what() << "... ok" << std::endl;
+  }
+  catch (...) {
+    std::cout
+      << "Unknown exception caught converting 'Three' to TestEnum... fail"
+      << std::endl;
+  }
+
+  return 0;
+}
+